[Elecraft] [OT] Lead-acid battery question

[Fred Townsend]

Vic let me clarify a few issues.
1.	At 665 AH your sealed battery is almost certainly a wet battery
(i.e. not a gel).
2.	A charging voltage between 13.5 and 14.2 is normal. 14.5 is a bit
high unless the charger is temperature compensated and the weather is very
cold (in the area of your generator). Another cause would be if you measured
the charging voltage without a battery attached (i.e. no load). In any event
your real problem does not appear to be too high a charging voltage.
3.	A measured voltage of 11.5 is a fully discharged battery. A 1 A
trickle charger would need 665 hours (actually even more because of
inefficiencies) to fully recharge that battery.
4.	Why did you replace the old battery after 10 years? In your almost
ideal circumstances it could easily last 25 years. The nature of lead acid
batteries is they fail when fully discharged. That can kill even a new
battery which may be the case now.
5.	Logically I must ask: Have you fixed the original problem? Battery
failure is likely a secondary problem. Ruling out two bad batteries (the old
and new batteries) has the generator become hard starting or else is there
another drain on the battery?

To find your problem you need to get a fully charged battery and monitor the
operation of the generator. Have you cleaned all the terminals and otherwise
verified the cables? Does it start hard? Does the started solenoid get warm
when not in use?  Is there 13.5 to 14.2 volts on the battery posts (don't
measure the cable terminals) when the generator is running? When the
generator is off is there a battery drain? It may take a milliamp meter to
tell but be careful not to use it while charging or you may smoke the meter.
Remember ammeters are always placed in series, never in parallel (instant
smoke).  

Try these procedures and get back to us.
73
Fred, AE6QL


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Vic K2VCO
Sent: Monday, April 08, 2013 10:13 AM
To: Elecraft Reflector
Subject: Re: [Elecraft] [OT] Lead-acid battery question

I see that my original post was not clear. I should have said that after the
first instance of a dead battery, after the battery was tested and
pronounced good, I replaced the VOLTAGE REGULATOR.

I'm not sure about the type of electrolyte, whether it's gel or liquid, but
I think it is liquid. The battery is sealed, though. The capacity is 665 AH
with "540 CCA."

I've received several responses to check if the battery is draining when the
generator is not running. I should have mentioned that I did this the first
time it died, and there was no current drain when it wasn't running.

On 4/8/2013 9:15 AM, Vic K2VCO wrote:
> I know there are those on this list who can help me.
>
> I have a 5 kW generator at my house. It runs automatically once a week 
> for a half hour to charge the (sealed) battery. The first battery 
> lasted for about 10 years! The present battery is about 2 years old.
>
> Some months ago, I noticed that it wasn't running. I found the battery 
> dead. I took the battery back to Batteries Plus where I got it; they 
> charged it overnight and tested it under load. They said the battery 
> was OK. When I started the generator and checked the charging voltage, it
was 13.8V which I thought was marginal, so I replaced it.
>
> Yesterday the generator would not start. The battery voltage with no 
> load was 11.5V. I left it on the charger all day. Then this morning I 
> checked the voltage and it was 13.5V. The generator started up and the
charging voltage was 14.5V.
>
> Do I have a bad battery?
>
>
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
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