Posted by RamRod Sword of Baal on August 30, 2008, 3:59 pm
I have 4 x T105 trojan batteries in series giving me a 24 volt system
They are currently just sitting there in case of a power failure and then
the will generate 240 volts AC via my inverter.
I feed them from a 40 amp basic battery charger, you know just a transformer
and a rectifier.
I put them on charge once a week or so and charge them at around 29.5 volts
and once then have been on for say 12 hours the current drops down to under
one amp, at the moment .7 of an amp, leave them on longer and the current
drops futher. BTW outside temperature now (Night time here 5 AM) is 24 c or
75 f. In the day it will be around 30 c or 86 f.
I usually leave them on charge for about 24 hours at a time.
Now as I want the batteries to have the longest life possible, is there any
out there who have experienced keeping these batteries alive for a long
period, and do they have any advice.
No, I do not wish to spend a lot of money on an automatic charger. A 40 amp
automatic charger cost over $AUS 1500.00
So any advise on keeping these batteries healthy for a long time? They are
curently about a year old and never been cycled, as I do have other power
back up system.
Before charging they usually are around 25.2 volts, and they never go below
that as that is when I put them on charge.
Posted by Vaughn Simon on August 30, 2008, 4:37 pm
> So any advise on keeping these batteries healthy for a long time? They are
> curently about a year old and never been cycled, as I do have other power back
> up system.
Since the batteries are apparently connected to nothing, I see no reason to
charge them more often than monthly. With a little monitoring, you may even be
able to get by with quarterly. I don't think it is a good idea to leave them on
that dumb charger for a full 24 hours. That would be like giving them an
equalizer charge monthly. You need to leave them on until they reach whatever
voltage the manufacturer recommends, and no longer. Constant overcharging will
reduce their lifetime.
If you value your batteries, I highly recommend an automatic float charger.
You could still use your present charger for bulk charging.
--
Vaughn
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Vaughn
Posted by Ken Maltby on August 31, 2008, 6:22 am
>> So any advise on keeping these batteries healthy for a long time? They
>> are curently about a year old and never been cycled, as I do have other
>> power back up system.
> Since the batteries are apparently connected to nothing, I see no reason
> to charge them more often than monthly. With a little monitoring, you may
> even be able to get by with quarterly. I don't think it is a good idea to
> leave them on that dumb charger for a full 24 hours. That would be like
> giving them an equalizer charge monthly. You need to leave them on until
> they reach whatever voltage the manufacturer recommends, and no longer.
> Constant overcharging will reduce their lifetime.
> If you value your batteries, I highly recommend an automatic float
> charger. You could still use your present charger for bulk charging.
Yes, a modern float charging circuit/device is actually a cheap
bit of labor saving insurance. That said, none of the gadgetry should
be taken to mean that you can ignore a consistent, if simple,
preventive maintenance schedule. Just get a clip board, & hydrometer,
and pick a day of the week to spend 10-20 min. on the task. Follow
the manufacturer's recommendations, for your specific batteries.
This should give you the general idea:
http://thesolar.biz:80/Battery_charging_article.htm
With your strictly "backup" use of this bank, you might get away
making it the minimum monthly routine, mentioned in the link
provided.
Luck;
Ken
Posted by You on August 31, 2008, 1:09 pm
> I have 4 x T105 trojan batteries in series giving me a 24 volt system
>
> They are currently just sitting there in case of a power failure and then
> the will generate 240 volts AC via my inverter.
>
> I feed them from a 40 amp basic battery charger, you know just a transformer
> and a rectifier.
>
> I put them on charge once a week or so and charge them at around 29.5 volts
> and once then have been on for say 12 hours the current drops down to under
> one amp, at the moment .7 of an amp, leave them on longer and the current
> drops futher. BTW outside temperature now (Night time here 5 AM) is 24 c or
> 75 f. In the day it will be around 30 c or 86 f.
>
> I usually leave them on charge for about 24 hours at a time.
>
> Now as I want the batteries to have the longest life possible, is there any
> out there who have experienced keeping these batteries alive for a long
> period, and do they have any advice.
>
> No, I do not wish to spend a lot of money on an automatic charger. A 40 amp
> automatic charger cost over $AUS 1500.00
>
> So any advise on keeping these batteries healthy for a long time? They are
> curently about a year old and never been cycled, as I do have other power
> back up system.
>
> Before charging they usually are around 25.2 volts, and they never go below
> that as that is when I put them on charge.
Your Killing your batteries when charging them to 29.5 Vdc on a weekly
basis. Once you get up to 28.8 Vdc your just boiling off H2. How often
are you adding water, to your cells?
Posted by m II on August 31, 2008, 1:34 pm
You wrote:
> Your Killing your batteries when charging them to 29.5 Vdc on a weekly
> basis. Once you get up to 28.8 Vdc your just boiling off H2. How often
> are you adding water, to your cells?
It's the current that makes batteries bubble. At that voltage, he is
putting in under one amp. It's nothing to worry about.
I have a small solar setup that keeps my batteries charged. With no load
on them for a couple of days, I see 15.1 volts quite regularly on the 12
volt battery bank. I fill up the electrolyte once every three of four
months. When I need power, I get a lot of work out of them before I see
a drop to 12.4 volts. I use the stereo, grinder, lights, drill and small
welder (60-70 amps output).
That high voltage is like a surface charge. If I turn on a small light
for a few minutes, the voltage will drop to the normal 13+ range. In
fact I HAVE to turn on a small light first, as the inverter won't work
at any voltage above roughly 14.9
Some people get a small 15 watt panel just to put and maintain that
levelling charge on the batteries. It saves the charger being used for
something that takes a long time.
mike
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> curently about a year old and never been cycled, as I do have other power back
> up system.