Sealed Lead Acid Batteries and heat

[nhfire77]

Does anyone have technical info regarding battery life. I have a customer that does not understand why their fire alarm batteries fail load testing every year. The panels are in a utility room that is routinely 85-90 F 24/7/365. (the panels are rated 32-100F)


I know this is killing them but need to show technical reasoning.

 

[satcom]

Does anyone have technical info regarding battery life. I have a customer that does not understand why their fire alarm batteries fail load testing every year. The panels are in a utility room that is routinely 85-90 F 24/7/365. (the panels are rated 32-100F)


I know this is killing them but need to show technical reasoning.

http://www.batteryuniversity.com/parttwo-35.htm

The way the charge rate is adjusted can make all the difference in battery life

 

[Robert Martin]

Battery Life

Battery Life

As satcom related the charge rate must be adjusted for the elevated temp or the batteries will be over charged and ruined.
I would go to the battery manufacturers website. They usually provide a chart to what the charge voltage should be at differant temps.

 

[nhfire77]

http://www.batteryuniversity.com/parttwo-35.htm

The way the charge rate is adjusted can make all the difference in battery life

What FACP allows you to change the rate? None that I am aware of.

 

[Robert Martin]

Sealed lead acid Batteries and heat

Sealed lead acid Batteries and heat

If they are not adjustable then they need to have temp comensation built into the charger.
You might need to contact the manufacturer to find out the adjustabilitiy. Simplex are adjustable or temp compensated.

 

[satcom]

What FACP allows you to change the rate? None that I am aware of.

What fire system? all of them before the 60's

The power supply in a fire panel has a set rate, it also has a recommended battery and depending on your load calcs, the charge cycles will differ, and that can create a problem.

We had some real cycle problems on a takeover system, the installer did the proper calcs, but another guy added strobes and it changed the load above, the supply limit, batteries life went down the drain.

 

[nhfire77]

What fire system? all of them before the 60's

The power supply in a fire panel has a set rate, it also has a recommended battery and depending on your load calcs, the charge cycles will differ, and that can create a problem.

We had some real cycle problems on a takeover system, the installer did the proper calcs, but another guy added strobes and it changed the load above, the supply limit, batteries life went down the drain.

My parents hadn't met yet in the 60's

The panels I am dealing with require about 4 ah, so they've got 7's. It's cheap money to replace annually, as long as I can make them understand the physics. For the company if you can reason it out, it doesn't get questioned.

 

[petersonra]

Battery life can often be extended by putting a fan on it to help dissipate heat.

However, you might lose the yearly battery replacement business.

 

[ELA]

The Power Sonic manual states this:

"While raising ambient temperature increases capacity, it also decreases useful service life. It is estimated that battery
life is halved for each 10?C (18?F) above normal room temperature."

As others have said I would be more concerned about how they are being charged. I have worked on a few systems that were killing batteries due to improper charging.

 

[Robert Martin]

Sealed lead acid Batteries and heat

Sealed lead acid Batteries and heat

As I previously stated. a lower charge rate or temp compensation is necessary. See below.
And for the wise comments I was working on FA systems in the
1970s and that is about the time many manufacturers started using battery back up.I have worked on hundreds of FA panels and I do know many are adjustable.
If you provide the manufacturer and model I may be able to find the battery charger adjustment process.

FYI Read carefully:roll:
Temperature Compensation
Power-Sonic batteries perform well both at low and high
temperatures. At low temperatures, however, charge efficiency
is reduced; at temperatures above 45?C, charge
efficiency increases so rapidly that there is a danger of
thermal runaway if temperature compensation is not precise.
The effect of temperature on charge voltage is less critical
in float applications, than in cyclic use where relatively
high charge currents are applied for the purpose of
short recharge times.
Temperature effects should definitely be considered
when designing or selecting a charging system. As a rule
of thumb, temperature compensation is desirable in the
charging circuit when operating outside the range of
41?F to 95?F (5?C to 35?C) prevailing ambient. The temperature
coefficient is -2mV/cell/?C below 20?C in
standby service and -6mV/cell/?C below 20?C in cyclic
use. For higher temperatures the charge voltage should
be correspondingly decreased.
The table in Figure 23 lists recommended charge voltages
for different temperatures.
AMBIENT CHARGE VOLTAGE PER CELL
TEMPERATURE Cyclic use Float Use
-4?F(-20?C) 2.67-2.77V 2.34-2.39V
14?F(-10?C) 2.61-2.71V 2.32-2.37V
32?F( 0?C) 2.55-2.65V 2.30-2.35V
50?F(+10?C) 2.49-2.59V 2.28-2.33V
68?F(+20?C) 2.43-2.53V 2.26-2.31V
77?F(+25?C) 2.40-2.50V 2.25-2.30V
86?F(+30?C) 2.37-2.47V 2.24-2.29V
104?F(+40?C) 2.31-2.41V 2.22-2.27V
122?F(+50?C) 2.25-2.35V 2.20-2.25V
Figure 23: Temperature Compensated Charge Voltage

 

[nhfire77]

You won't find an open source FACP with adjustable battery charging, eg. Silent knight, firelite etc.

Some older FCI and mircom addressable had hi/lo settings, nothing more.

I know of no currently available ones that do, except maybe simplex.

 

[gadfly56]

You won't find an open source FACP with adjustable battery charging, eg. Silent knight, firelite etc.

Some older FCI and mircom addressable had hi/lo settings, nothing more.

I know of no currently available ones that do, except maybe simplex.

None of the major product offerings from Siemens (System 3, MXL, XLS) allow for adjustable battery charging. The PSC-12 power supply for the XLS does incorporate a thermistor which monitors battery charging.

 

[MichaelGP3]

You won't find an open source FACP with adjustable battery charging, eg. Silent knight, firelite etc.

Some older FCI and mircom addressable had hi/lo settings, nothing more.

I know of no currently available ones that do, except maybe simplex.

I recall that the hi/lo charge rate settings you're referring to were provided so that one could adjust the charging voltage for either sealed lead acid (low) or Ni-Cad (high) batteries.

 

[nhfire77]

I recall that the hi/lo charge rate settings you're referring to were provided so that one could adjust the charging voltage for either sealed lead acid (low) or Ni-Cad (high) batteries.

I did not know that.


I appreciate any other info anyone else may have on SLA batteries and their installation environment.

 

[MisterCMK]

What kind of panels are they?

 

[nhfire77]

What kind of panels are they?

notifier FSP-400 older 4 zone conventional panels.

 

[MisterCMK]

Hmm

What is the charging current with AC on and fresh batteries?

 

[Besoeker]

Does anyone have technical info regarding battery life. I have a customer that does not understand why their fire alarm batteries fail load testing every year. The panels are in a utility room that is routinely 85-90 F 24/7/365. (the panels are rated 32-100F)


I know this is killing them but need to show technical reasoning.

FWIW, we used to make chargers (and sometimes still do for specialist applications). They have temperature compensation that follows this:

0C=32F
45C=113F

 

[nhfire77]

Hmm

What is the charging current with AC on and fresh batteries?

Last year was the last time I measured it, i think it was 100-200mA initially, but quickly levels off to a float charge.

There is eight of them, and I checked them all against the manual last year, they were within spec.

As a note: The batteries are not dying they are failing their simulated load/capacity testing.

 

[MisterCMK]

How are you doing your testing?