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General => General Discussion => Topic started by: dor123 on May 22, 2015, 07:32:35 AM



Title: American emergency lighting, versus non-american emergency lighting
Post by: dor123 on May 22, 2015, 07:32:35 AM
I've noticed that american emergency lighting, is totally not what we have here, and outside North America.
While here (And I think every country outside North America), our emergency lighting, are either portable lanterns, wall mounted or ceiling fixtures with fluorescents or LEDs, (Sometimes with diffusers) that spread the light evenly, in North America, it is usually sealed beam incandescent or halogen PAR floods, that produces a concentrated light.
What is the reason for the huge difference between the american and the non american emergency lighting?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 22, 2015, 07:53:55 AM
the emergency lighting at my middle and high school are mostly small batttery powered LED exit signs, and we also have a generator. the troffers in the elementary school im pretty sure had red cased bodine back up ballasts. we also had the battery operated halogen wall spotlight fixtures but they were replaced with LED systems.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 22, 2015, 08:09:11 AM
I understand the question as to ask about the lanterns providing just illumination, so not the exit guide signs or so.

I guess it is a combination of few aspects:
- It was the first counry with huge buildings, what meant quite strong potential for a high number of fatalities in case something bad happens, just because there are many people present with quite lengthy eacuation time, so the strong need for the emergency equipment. The small buildings in the rest of the world meand way less people involved in the incident and event when it happened, the small building means very fast evacuation. So no such strong need for the emergency equipment in general.
- They were first able to make such decentralized battery powered emergency lighting systems (again given by the fact the wiring was one of the first thing to get damaged in the huge buildings), but at that time just incandescents were available as the only light source with sufficient reliability suitable for battery operation. In order to limit the energy eed, the designs have utilizedquite strong focusing by the use of reflectors. In other parts of the world the centralized battery system were still in use. And when the need for such decentralized system arrived, the more efficient fluorescent technology became available.
- The general prefference of the integrated lamps with their reflectors (it was mastered by their factories and it allowed the design of the fixtures to not be sensitive for any accuracy or so, so cheap to produce, yet still with guaranteed performance). The rest of the world preffered more elaborate fixtures (with all the optics,...), but plain simple universal use lamps. So for the emergency they just used the nondirected diffuse style illumination. And that then find the way into the reated standards: The US ones are designed more with the focused light in mind, the other world with the diffuse light in mind. So design the installation according to the US standards with diffuse light becomes quite problematic and vice versa.

- Then the other is the mindset of not changig something proven, reliable, mainly when so many people safety depend on it, mainly when there is not much reason for it (that lighting does not cosume any significant power anyway, regardless how efficient or inefficient it is; the only difference is the battery size). That is not that special, but when other parts become accustomed with the fluorescents (and their advantage of better illumination covering more area with the same power), they just keep using that technology as the "proven" one. The shift towards LED's is then quite common, but as in the US people become accustomed to the focused lights, while the others to the diffused ones, the LED's allow simpler construction of the diffused (you do not need as dense arrangement), the LED's made according to the non-US style arrived first. And it get accepted faster, because one of the fluorescent drawback is the need of the rather high voltage for ignition, what becomes a problem once water gets into the light, affecting the reliability in some situations. With LED it will light for some time even when all the unprotected internal installation of the fixture becomes completely wet. It won't survive it long term, but at that moment it will still work. Plus for such low power levels the LED's are the most efficient light source for quite some time, so suffice with really small, so cheap battery.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: dor123 on May 22, 2015, 08:25:08 AM
Thanks Medved.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: nicksfans on May 22, 2015, 04:36:39 PM
The newest emergency lights in the US are LED, but are based on the design of the older ones. The low voltage incandescent lamps are typically only found in installations older than 5-10 years, but incandescent fixtures and lamps are still available for purchase. In many larger commercial buildings, some of the overhead linear fluorescent or CFL fixtures have emergency ballasts.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 22, 2015, 11:49:29 PM
Now that LEDisease is spreading rapidly, we could expect to see little to no halojen emergency lights. They have new requirements to retrofit exit signs to LED.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 23, 2015, 12:38:21 AM
That is nuts, whats wrong with the existing ones that are already installed and work ?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 23, 2015, 06:26:36 AM
That is nuts, whats wrong with the existing ones that are already installed and work ?

Usually the battery fails after some time, so needs to be replaced.
Many makers require the battery (and after some time even the complete fixture) to be replaced at certain intervals even regardless how they appear - just because the endurance tests have shown increasing rate of hard failures as it gets older. It is about the type of failures, when the capacity seems to be still OK during the periodic test, but it just suddenly stops working at all. But with this type of equipment you just can not afford such failures at all.
And I guess even when not the manufacturer itself, the fire code does require the complete fixture to be replaced after some period of time, otherwise it treat it legally the same as not installed.

There is no need for the LED efficiency in terms of the power consumption of the fixture, but because the safety standard requires certain light output for certain time (and it is very strict on this), the high LED efficacy means way capacity battery is sufficient. And that lower capacity means the complete fixture gets way smaller, cheaper and e.g. easier to have more margin in the battery capacity, so at the end it's longer life.




And the LED types look the same, because their performance are just exactly the same as for the older incandescents, the fir code does not care what technology is inside, it asks just for certain performance criteria...


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 23, 2015, 08:28:45 AM
Over here battery replacement is in the required maintenance, but no requirement is made to replace the lantern. It is assumed to be intact "forever", as a properly made lantern should in fact be


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 23, 2015, 08:51:05 AM
Over here battery replacement is in the required maintenance, but no requirement is made to replace the lantern. It is assumed to be intact "forever", as a properly made lantern should in fact be

The thing is, after you took it down and disassemble it few times to replace the battery (and do the inspection), it cracks somewhere and therefore it has to be replaceddue to that reason.
And some components in the control electronic (electrolytic capacitors) tend to age and get unreliable over time, so e.g. the charging control may stop working properly, compromising the runtime.
Plus dirt uses to gather inside and compromises the light output, but it is difficult to remove it without damaging the lantern.

It is true, it was on an optical smoke detector, where the complete device replacement (10 years after the date of manufacture) was required by the manual (and I think it comes from the fire code), so it could be it is not the case for the emergency lanterns, but if there would be such limit, I don't think it will be shorter than similar 10 years period.
And that uses to be the time, when all the installation usually get replaced anyway...


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 24, 2015, 08:57:40 PM
I have also seen these red lights glowing within the fluorescent troffers at school, even when the light is off. Is that indicating of an emerjency ballast or circuit breaker that is still on?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: nicksfans on May 24, 2015, 09:03:15 PM
The red light indicates the presence of an emergency ballast.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 25, 2015, 01:10:26 AM
I have quite a few fluorescent exit signs and emergency lights

All of them are built sturdy enough to last many times of opening for battery and lamp replacements. I opened each one just for looking and playing with it probably many times more than the number of times it is opened in real use, and there are no signs of wear on the structure

I have to see yet one that does not work due to a bad capacitor. Due to them being powered by 50 Hz transformer in normal (charging) mode, the capacitors see very low ripple and stay at ambient temperature. The ambient temperature is either room temperature, or a bit higher from a 8W T5 lamp on Swtich Start warming the atmosphere inside the same enclosure, but it does not give a lot of temperature rise. Also, i suspect that the circuit itself is not really sensitive to the capacitor parameters. I have to try some day to desolder the capacitor completely or solder in a "defective" one (lower capacity in series with resistor) and see what happens

The exit signs are often IP40 and up so there is no problem of dirt ingress. In others nothing prevent you from wiping the diffuser clean when you are up there to change a battery....



In the ones i have here, the red LED is parallel to the charging diode+resistor pair, so it indicate that current is going into the battery. Unfortunately EOL batteries go short circuit or high impedance so the LED keep lighting even when the battery is EOL. To really test it, for a quick test some lights have a test button, for a full test you flip the breaker off and let them go for the rated time

They get 2 incoming hot wires, one from the switch that goes to all lights, and one from before the switch (so permanent on) that goes to the emergency pack

See here how thy are constructed :
http://www.lighting-gallery.net/gallery/displayimage.php?album=2158&pos=80&pid=60414
http://www.lighting-gallery.net/gallery/displayimage.php?album=2158&pos=31&pid=108206
http://www.lighting-gallery.net/gallery/displayimage.php?album=2158&pos=44&pid=107417

And i have some more which i have not yet uploaded, they will come soon


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 25, 2015, 02:16:23 PM
Thank you, nick.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 25, 2015, 02:23:32 PM
Interesting, I've never seen anything like the barak, which is actually good on lamps. Most inverters are he** on tubes, especially since they are underdriven and/or cold cathode start.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: dor123 on May 26, 2015, 02:45:13 AM
The inverter inside the Gaash Barak II, also underdrives the lamps, but it is rapidstart (Cathodes heating), and not instant start. Thats why it is good for the lamps.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 26, 2015, 10:53:37 PM
With emergency lights the tube life is practically never any problem, even when the tubes are cold started and underdriven. You barely need more than few 10's of hours with 20 starts from them over the complete installation life...


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 27, 2015, 12:13:21 AM
The lamps fail already after a couple of battery depletion runs. The ballast can keep powering the EOL lamp at cold cathode and it works (in my home i move EOL lamps from normal ballasts to continue use in an emergency light), but the light output is much lower than intended

If the same lamp is switched between normal and emergency ballasts then it is a problem, the emergency kills the lamp and after a while more it fails on the normal ballast


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 27, 2015, 09:38:54 AM
Then the emergency units have other problem:
Missing battery undervoltage shut down. This should at first prevent really deep battery depletion, so prevent damaging the battery (after 2'nd or 3'rd complete discharge the runtime with the undervoltage present would be larger than without that feature, even when it will look like it will cut out part of the runtime) but as second it prevent the inverter to operate the lamp on the really low power, when the inverter has no chance to warm up the filaments.
And if the undervoltage is missing, then the long lamp life does not make much sense either, when you have to service the unit due to dead battery anyway...


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 27, 2015, 09:52:02 AM
Those emergency inverters get about 120Lm out of an intact 8W T5. The inverters for 36W lamp get about 480Lm (data taken from Gaash, a lantern manufacturer). That mean power input on the order of 2W to the 8W lamp, and 8W to the 36W lamp. It have no chance to warm up the cathodes anyway

The long lamp life does make sense - Why should a lamp be wasted (pollution, cost etc). Even if the maintenance worker is right now up on the ladder, the lamp is still not "free"....


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 27, 2015, 06:37:01 PM
I didn't realize how under driven those are. In theory, could you run the f8 on a f36 emergency inverter since the f36 puts out only 8w?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 27, 2015, 07:06:54 PM
I can try. I think it will put less than 8W into the 8W lamp due to its lower arc voltage


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 27, 2015, 07:10:00 PM
Ok. Just get back to me when you can, thanks.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 28, 2015, 01:24:15 AM
The 20..25% of the rated current is still able to warm up the filaments, but it means it should be delivered even in the cold cathode state. And that is the main problem: The power will become temporarily larger during the cold cathode mode (because of the higher voltage drop) and that is the problem with many ballasts: They are just not able to deliver that higher power for the warmup (or better to say the weaker batteries are not able to deliver that power; that is the importance of the undervoltage cutout).

And for the lamp replacements: The problem is, the lamps degrade on their own when not in use (mercury settling, atmosphere poisonning,...; all that is normally supressed by the lamp operation), so it is not able to work correctly after the long sitting time, mainly when the lower power is involved. The main reason to replace the lamps with the battery comes from there...
And the reason for underdriving the lamps is just the efficacy and consequently the environment load as well: For the required 130lm, you may use either a 4W lamp at full power lasting all the 10 years of the fixture life (or even longer), or an 8W one at 2W replaced every 3..4 years. Obviously the later suffices with half of the battery size for the same runtime, so half of the lead or cadmium waste with each battery replacement. So for the environment the extra tube is way less load than the larger battery size...


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 28, 2015, 09:50:37 AM
And then the batteries end up going EOL and ruining the charge circuit due to the lack of under voltage cut out.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 28, 2015, 12:16:07 PM
With lead acid, the battery EOL is usually either loss of the water due to the constant float charging (mainly when the charging voltage is not made with proper temperature dependence (it should have slightly negative temperature coefficient, so decreasing with increasing temperature). Less likely form of the battery EOL is the electrode sulfatation, but that is usually linked with long time with missing power (a seasonal facility not used off season, with the power switched off completely,...)
Similar problems are with NiCd's.
But the missing water can not cause the charger circuit to overheat or any other condition leading to it's malfunction. For that many products suffice with their own design (e.g. "2W" resistor loaded by the full 2W power dissipation or so; there I do not understand, why for a 2.4V battery they use 9V transformer and dissipate the 7.5V on that resistor).

Only the NiCd may end up short circuit (after cell reversal; but that exactly is supposed to be prevented by the undervoltage cut out), but there just one shortened cell can not cause the charger to overheat, if designed at least reasonably.



Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 28, 2015, 03:38:47 PM
I see. Thank you for the explanation. Now do they still use lead and NiCd batteries or have they started using LiPo or Li ion?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 28, 2015, 11:10:11 PM
The Lion/LiPo are completely unsuitable for such duty, their lifetime would be way shorter than usual for the lead acid or NiCd's.
Although I do believe, many cheepeese makers will use them even there - for the ~1Wh capacities they are becoming the cheapest choice and their cell voltage pretty well matches the LED forward voltage, so even simple linear current regulator means high efficiency, so they look very attractive for someone who wants good runtime of brigh light when showing off at low cost, but don't care that much on the lifetime.

The Lithioum ion based cell performance lies in applications, where they are all the time completely charged/discharged, there they really outperform all other usual chemistries, but not in those stand-by applications.

These Lithium based cells have completely different dominant aging mechanism than all the "classic" chemistries.
With the classic batteries the charging/discharging means the electrodes change their physical size, what leads to fatique cracks, so the dominant aging of the electrodes is cycling.
Then with lead-acid the crystallization of the PbS causes the degradation when discharged, with Ni-based the dendride growth when electrodes are reversed (= cell deep discharged below about 0.6V means one electrode gets already reversed)

But with Lithium similar effects are nearly nonexistent (= they are hidden behind the other degradation effects), maybe except the electrode polarity reversal (deep discharge way below 2.5V).
The dominant wear mechanism is a thin layer growth associated with higher voltage and of course temperature.
This has quite severe consequence for reading the "performance" data:
A classical secondary cell "endurance" test is repetitively charging/discharging the cell, till it looses capacity to certain level. When an NiXX shows 500cycle life, it mean with one cycle/week about 10 year life.
But the fact the LiIon is showing 10k+ cycles in a 3year lasting test does not mean the battery will last 200 years, in reality it will die within the same 3 years period as the test have lasted or even shorter. That is, because the dominant aging mechanism is, how long (accumulatively) the cell hat spend at each given voltage and that was the same with the tests with 10k cycles, as in the real life. And the "shorter" comes from a situation, when the battery stays most of the time fully charged.

So with the emergency lights the batteries are practically 100% of the time fully charged, what means LiIon life shorter than about 2 years...



Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 29, 2015, 01:22:02 AM
Provided that i have 8 year laptops which batteries still work (with ~1/2 original capacity), i do think a Li Ion may be a good choice for emergency lighting

If the problem is 100% charged state, why not put a 1.5x capacity battery and keep it charged to 2/3 ?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 29, 2015, 08:08:48 AM
Plus that would put tons of stress on the lithium batteries. They are prone to explosive failure when overcharged or overheated, which could happen in an emergency fixture.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 29, 2015, 11:06:27 AM
No stress, its way lighter duty than what the same battery would get in a laptop

Proper charging circuit (and not "higher V through big resistor" as used with NiCd) is essential for Li-xx batteries, and that prevents overcharging

Overheating can only happen in tight lanterns in which there is a working lamp at normal time. A lantern with some more air space around the gear does not get very hot, definitely less than some laptops out there. If you place the battery away from the ballast or lamp cathodes itll only be marginally warmer than room temperature. In an emergency-only lantern there is no problem, it is at room temperature at all times anyway


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 30, 2015, 04:52:17 AM
Controlling the charging of the LiIon batteries belongs to the easier tasks, it just means reduce or switch off, once the voltage reach certain level. The only trouble is the required accuracy. However once you overcharge it, it really tends to end up in flames.

Their aging goes mainly with cell voltages exceeding 3.9V and (as nearly every chemical reaction) is highly accelerated by the heat.
Of course, using just the ~3.8V as the float voltage will improve the lifetime to about the same as  SLA's, but then the usable energy density would become comparable to the NiCd or NiMH (when the NiMH is supposed to handle the constant overcharging, the attainable capacity is about the same as the NiCd) or more expensive than SLA.

Plus the fact you have seen a piece that have lasted unusually long does not mean the life is sufficient (well, maybe if you want to "compete" by quality with the most cheepeese makers, then it could be assumed as sufficient). It would have to be 99% of the produced batteries lasting that long, when you want to state certain period as a life rating to count on.


The sealed NiCd/NiMh are the most difficult cell to control without overcharging: Their voltage is very strongly temperature dependent, what when combined with the heat generated during the overcharge (with NiMh even with normal charging) causes the normally rising voltage as the charge level increases is reduced by the cell self heating, so e.g. simple floating voltage regulation as a means of automatic charge termination (working with lead acid, LiIon, as well as wet NiCd's) does not work (unless there is accurate cell temperature sensing coupled to the voltage regulation). This behavior was the primary reason to design the cells so, they will be able to handle long term overcharging (recover the water from the gassing overcharging reaction) and in the electrical part use just that simple charging resistor, without any charge termination at all and completely relying on the internal water recovery mechanism.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 30, 2015, 05:16:57 AM
If tyhe battery voltage goes up as it charges AND up as it heats, then a simple on/off charging control with high level, low level and hysteresis would suffice.... Somehing along the lines of that 555-timer charger i designed a couple years back

How long would a battery last on that vs on float ?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 30, 2015, 05:47:57 AM
If tyhe battery voltage goes up as it charges AND up as it heats, then a simple on/off charging control with high level, low level and hysteresis would suffice.... Somehing along the lines of that 555-timer charger i designed a couple years back

How long would a battery last on that vs on float ?

It goes up as it charges, but DOWN as it heats. That is then responsible for the famous "negative dV/dt" at the end of the charging: When the cell gets fully charged, the voltage related to the charging stops rising, but the heat generated by the overcharging causes the temperature to rise, so the overall voltage starts to decrease.
But that could be usable only for fast charge termination (and even that is not that much reliable), but not for the permanent maintenance - there it tends to make the setup rather unstable: Once the cell starts to overcharge a bit, it heats up, decreasing it's voltage, so drawing more current and so on.

With the maintenance charging you need ideally to keep the cell voltage just below the gassing level, but stil above the electrochemical voltage, so you keep the cell really charged. That voltage window is really small (low 10's of mV), so in order to really work, the charger voltage (regardless if it is formed by a linear regulator or a comparator switching ON and OFF the charging current - the type you present) has to track that window.
The lead acid are quite temperature stable and the charging (nor overcharging) does not generate any significant heat, so just a constant voltage is sufficient to keep them charged.
But with the NiXX you have to track the internal cell temperature, what means tightly coupled temperature sensor and very limited charging current, so the temperature difference between the core and surface is small enough. Quite complicated arrangement, mainly the battery pack itself. The constant overcharging is way easier and when supported by the cell design (so that means not exceeding the rated maintenance charge current; that means for standard cells about 50mA for AA size or ~100mA for a subC size cell; regardless if it is NiCd or NiMH - really given just by the cell size), way more reliable and leading to the longest life.

The LiXX are different mainly, because the overcharging there is extremely damaging - therefore these can never be run that far, that's why the extreme requirements for the charger termination voltage accuracy (better than 20mV on 4.2V to keep the capacity and life within the rated limits).


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 30, 2015, 05:58:34 AM
Then, as the battery charges initially dV/dt is positive, as it starts to heat dV/dt is negative. Between them dV/dt is zero. How about a charger that cuts out on dV/dt = 0 ?


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 30, 2015, 08:01:58 AM
The "dV/dt=0" point is, when the overcharging already takes the full current and the battery is already pressurized. In fact the overcharging itself does not directly heat up the battery, it "just" decomposes water to the separate hydrogen and oxygen. But it is the water recovery reaction, where these are combined back into the water, what generates the heat. And this sequence means, the heat generation always lags the actual overcharging (first the gasses get generated, then they have to pass to the extra electrode area, pressurize there a bit to gain some momentum and only then recombine back to the water and generate the heat.)
And in fact passing the "dV/dt=0" is the point, recommended to terminate the NiMH charging. The reason is, even the main charging reaction of the NiMH generates some heat (together with the Joule losses), so they get already preheated, so have less thermal margin, so the need to stop that earlier. And that generated heat means, once you want to use really fast charging, the temperature during normal charging will reach the maximum allowed, so there would be no room for the detection via the voltage. The only method used for that rapid charging is to detect the increasing pressure. Either via a strain sensor within the cell plastic sleeve, or using a pressure actuated disconnect contact inside of the cell (the "15 minute charging" cells).

With NiCd's the charging reaction actually absorbs heat, so they stay cool even beside rather high Joule losses with really very fast charge rate; therefore the tolerance of the NiCd towards that high charging currents (the only thing deteriorating the cells at high currents is the heat; no heat means no degradation). The same means, the dV/dt is way more pronounced, so it could be sensed even by just an analog circuit when high enough charging currents are involved (NiMH needs digital signal processing, as the currents can not be that high, so the slopes are way slower, so become too slow for time constants feasible only in an analog circuit). And because they get colder during the fast charging, just sensing the temperature to exceed e.g. 35degC threshold becomes the simplest fast charging control for them, when the temperature could be sensed (most battery power tools use this method, either by part of the cell being naked to be touched by the charger sensor, or a thermal switch being integrated inside of the pack)

And by the way pretty ingenious way was used in the Toyota Prius: The NiMH cells are made as wet designs, pack of few of them sealed within one pack, with the water regeneration place (serving that group of cells) being separated from the main cell's body (and attached to external cooling system). That means the heat from the overcharging is generated outside of the cells, not threatening any sensitive parts, could easily operate at very high temperatures, while the cells itself remain rather cold, while dissipating a lot of overcharge energy. That arrangements makes the regeneration dynamic breaking pretty simple: No need for extra overcharge control, dissipate all the energy required by the driver, always fully charging all the cells before redirecting the energy into a power dump (in fact not needing any separate power dump in the car at all, the cells can pretty well serve that purpose)


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 30, 2015, 08:20:23 AM
In a working emergency lantern the battery may be located next to a working lamp or its ballast (the mains powered one). Then it means that the battery will reach the temperature/pressure of dv/dt reverse in earlier stage

In an emergency-only lantern on outer wall under rain or snow (water proof lantern), temperatures will be low, and the battery may keep charging....

What happens in those cases ?

What happens in the event of change ? - Say the weather proof lantern is a small plastic "melt light" with high power PL or 2D, it was switched on and hot inside, and reached full charge under that temperature. Then it is switched off and starts cooling down to ambient temperature (say near 0C)


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: hannahs lights on May 30, 2015, 11:18:35 AM
What you say about battery life seems to be true our housephone has 2 triple A Lion battery they have only lasted about 2 years because the phone spends most of its life on its charging bed. They do seem to get rather warm even when they've been on charge for days


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 30, 2015, 01:43:02 PM
Li-Ion cell voltage is three times that of other cell types, it mean that the user swapping it with any other type of battery will either have a phone that does not work (supplied with 2.4V instead of 7.2V), or blow up other stuff that he put the Li-Ion battery into

I really doubt any sensible manufacturer will make a home appliance that use Li-Ion batteries in a size interchangeable with other batteries. Most likely the phone uses NiMH or NiCd


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 30, 2015, 02:20:41 PM
Some batteries take constant charjing better than others. This issue of batteries malfunctioning due to constant charge could be fixed by a circuit that detects battery level. Some of those lanterns had those charge detection circuit damaged due to EOL batteries.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on May 30, 2015, 02:43:42 PM
I have yet to see a lantern with an on/off charge controller.... All the ones i have are just the resistor that limit the current

And those fail just as well :

The resistor takes the voltage difference between the supply and the battery. In a charging after a power outage, in the beginnning the battery voltage is low, and high voltage fall on the resistor, then as the battery voltage goes up the resistor voltage drop comes down

In lanterns in which the resistor is marginal in power rating, it is designed so the resistor is on the edge when the battery is empty, and assuming that it does not take very long to charge, the resistor is not overloaded like that for long. But when a NiCd battery EOLs it goes shorted, then all the available voltage fall on the resistor, it heats up and burns out or damages the PCB


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 30, 2015, 09:00:13 PM
The new led lanterns have the battery level cutout so that it won't overcharje. I think that the portable battery powered lantern I found at a thrift store had a charge cutout for the NiCd batteries that you could install. You could use regular batteries, just don't charge them.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 31, 2015, 03:15:57 AM
@Ash: Well, if the resistor is not properly rated, it indeed fails sooner. The thing is, normally the low voltage state should not happen in the first place (because of the undervoltage cutout) and even when it happens, normally it takes few minutes for a healthy battery to recover to the 0.9..1V/cell level and that the resistor should stand well, even when overloaded. The problem is indeed, when the battery fails short circuit, then the overloading is not time limited anymore and then it really may fail. The thing is, many of these fixtures are not designed for anything being really replaced over the complete fixture life. Quality NiCd's with proper undrvoltage protection tend to last there 10 years (with one discharge cycle per month in average) and that is the expected fixture life as well (plastic degradation,...)...
You may ask why not replace just the batteries? Well, if the new battery pack costs the same or even more than exactly the same fixture, plus it is rather hard to get, it does not make much sense...

@Solanaceae:
There is significant difference if the fixture is a certified emergency illumination device, or portable lantern (even when it has "emergency" feature). The first are always fixed mount lights
Depends on the battery chemistry. With the NiXX there is no need for any cutout at all, but those are not used in portable lanterns (the Cadmium is anyway banned in consumer products).
In older models were used SLA batteries, but mainly with the newer consumer products you meet nearly in 100% the LiIon, as with the portable lantern the expected use regularly on batteries.
And both SLA and LiIon require the voltage charge control (cut out or regulation).
And the LED voltage matches the LiIon's, those are really getting popular in those portable lanterns and there the voltage control is really a must...

The situation with the emergency illumination is a bit different, there the light operates nearly 100% time on the charger, whose only function is to keep the battery ready to deliver the rated illumination time at any moment. For that the 3x NiCd's are the best performance to go with LED's. The LED itself prevents the overdischarge, so no need for any special circuit, for the charging you suffice with just that resistor (well, I more like an incandescent, as at first it dissipates the power way easier, and seconds it provides very simple diagnostic about the battery state - dark => no power, dimmer glow => charged, barely red => battery EOL, bright => battery empty or when long time battery EOL; and you even do not need any ladder to check it).


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: hannahs lights on May 31, 2015, 06:17:37 AM
In an earlier post someone put that the red LED indicators in emergency lights are in parralel with the charge resistor is this still done with newer EM lights? The reason I ask is there are some on a public building I see and the green LEDs seem very bright even though thebattsrys have been on constant charge for maybe 6 months or even longer we are lucky here powercuts are very few and farbetween


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 31, 2015, 07:08:49 AM
What I've seen on the "just a resistor" chargers, the LED was indeed just parallel to the charging resistor (with it's own series small resistor, of course). The intention is to allow at least some indication of the battery state (similar as the incandescent would provide).

However when the charger uses some more advanced charger circuit, the LED could be supplied separately, turned ON or OFF by the diagnostic output of the charger electronic.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on May 31, 2015, 08:24:42 AM
Or you could use a more sophisticated circuit and have one of the color changing LEDs (red for lo/no charge or charging, and green for full).


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on May 31, 2015, 12:17:21 PM
Or you could use a more sophisticated circuit and have one of the color changing LEDs (red for lo/no charge or charging, and green for full).

Way better is to keep these LEDs separated: With quick look, you may misinterpret the color, but you will see pretty well, if there is just one or two LED's ON, even when you would be color blind...

And it becomes a standard (dunno how official, but most emergency fixtures behave that way):
Control light ON => Input charging mains connected, fixture working (but does not mean the battery being really charged)
Only main lamp ON, control OFF => Input power missing
Both main and control OFF => fixture faulty or main power OFF too long (as inspections are usually done when the power is running, it likely means input power fault)
Control flashing (only in some fixtures) => Battery running flat; if the main lamp is OFF, it was shut down by the undervoltage protection

Except the flashing (flat battery) signal, all is ensured by just the LED (or the incandescent) in the charging path and normal lamp control (LED is ON only when the charger is running and the battery is connected, what means mainly all fuses are OK, wiring gets power, batteries are not dried out so open circuit,...).


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on June 01, 2015, 05:53:12 PM
Why 10 years for the life of the luminaire ? They can easily last many times that - Good plastic does not degrade noticably in 10 years, neither do any of the other components except battery


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on June 01, 2015, 08:01:16 PM
You can't expect new lanterns to last that long with cheap manufacturing and crappy parts.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on June 01, 2015, 10:53:40 PM
In big part the 10 years come from the fact the user wants to just refurbish the whole site and with everything (carpet, arrangement, furniture,...) new, he will use even new light fixtures, so the old ones would be scrapped (not much workers would spent any extra time to take too much care when removing old things, except those, which could be sold still at high enough price)


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on June 03, 2015, 12:44:58 AM
Now this is wastefull

Here the time between "refurbs" is getting shorter over time as well, places built in the 50s..70s were still original up to at least 90s and sometimes early 2000s - so 30..40 years average, but now places built in the 80..90s are mostly the target of refurbsihmants so 20..30 years. I cannot say i like this trend. But we are mostly not in the 10 year mark yet

In part, the original construction feature and quality is often far greater then what they put in nowadays anyway (cheapest grid ceilings, abandonment of building features like windows and vents, lowering of ceilings... turning great places into yet another low-ceiling boring cubicle space)


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Solanaceae on June 03, 2015, 04:19:59 PM
I hate when perfectly working fixtures and bulbs are thrown out or scrapped out, that grinds my gears.  >:(
The people who do remodels and donate the old stuff to habitat are the backbone of habitat and us collectors. On the other hand, this modern society is wasteful and all about doing things fast and effectively, so the trips to habitat will put a "damper" on the project.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on June 03, 2015, 05:33:26 PM
I noticed some tendedncy...

In the original construction (of 90s and earlier), normally the best quality of original material available at the time is used. That mean all electrical, but also structural elements, doors, windows etc

In old refurbishments (done in the "old days", so 80s and before), the refurb planners did recognize that the stuff is good and a lot of it stayed, they changed what they see right and put effort to match it with the original design and make it fit with what is left untouched

In new refurbishments they tend to tear out everything that stands in the way, and if the refurbishment is only partial, you can tell straigth away where the composition does not look right. Also with money spent on tearing down everything, everything (of the new stuff put in) is cheaper in both appearance and actual quality


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on June 06, 2015, 10:51:43 AM
The main motivator for the "10 year period" is, with public places all the furniture, carpets, floors, etc are highly worn out, so really needs replacement. The lighting just goes with it.


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Ash on June 06, 2015, 11:48:12 AM
Each of the items can be replaced at its own time. There is no relation betwee lighting and furniture or carpets.....

Indoors public place (reception rooms etc) furniture here is mostly made of metal with synthetic sheatings/pillows, and there are few very common models from some manufacturers. It is not uncommon to replace it in spot replacement (when one unit breaks or tears) since the exact same model is still available from the manufacturer, so the replaced unit does not stand out from the others

How common are carpets in public places in the outer world ? Here most public places have stone floors that last pretty much forever, carpets are present mostly in places like theater halls, libraries etc


Title: Re: American emergency lighting, versus non-american emergency lighting
Post by: Medved on June 07, 2015, 06:44:42 AM
There is one aspect forming quite strong relation: Once one of these is refurbished, the facility can offer either very limited or no service at all. That means quite high loss (either directly profit, or just the fact they have to pay the all the rents, but are not able to provide the service they are supposed to), so good management looks for ways to eliminate that.

When all the equipment is replaced at once, there is just one shut down and then all equipment becomes new, so no such disruption should be necessary for the next 10 years.
That means quite significant savings, way higher than the remaining value of the still usable equipment.