[OZAPRS] SOT : Lead Acid battery reconditioning

[Terry Collins]

Chris Hill wrote:
> Hi Guys,
> 
>  
> 
> Sorry for the slightly off topic (SOT) question, but a 240VAC outage
> yesterday took my satgate down.  so it's time to service the UPS!
> 
>  
> 
> The UPS is a fairly large one (a 1300W unit made by On-Line Power, Inc.,
> similar to the unit at http://www.onlinepower.com/products/tbs.html),
fitted
> with six 12V 50AH lead acid batteries.  The existing batteries are
> PRC-1250XL made by Power Battery Company, Inc, NJ, USA.  (A data sheet
for
> the series is available at
http://www.powerbattery.com/pdf/prc-1250s.pdf).
> 
>  
> 
> It's going to cost approx $1300 to get a brand new set of batteries, 

HUH! I buy 100AmpHr Trojan (US) deep discharge batteries for $200 each. 
You can also get Century (AUS) 75AmpHr for about $125 (Super CheapAuto) 
These are only lead acid. You must be paying double the price because 
they are glass matt.

> so it may be worth investing in a decent battery refurbishment /
reconditioning.

Test them yourself
Do you have a garage/workshop/backyard?
Can you read a voltmeter?
Do these batteries need distilled water top up?

There is a Battery FAQ here.
http://www.uuhome.de/william.darden/
Sometimes it is a little confusing between car batteries (rubbish) and 
deep discharge..

Basically, buy yourself a 12v battery charger. I just use the Arlec 6 
from Big W.

Check fluid level and top up if needed (no idea about glass matt)
Charge each battery up to what the FAQ says. 14.?V
Let them sit for a day after charge.
See if any is below 13.2*(?)V as recommended in FAQ.

Ideally run them through a discharge test down to 50%  (?, 11.5V)
They recommend only discharging lead acid to 50% for longer life.
But you have glass matt, which may go lower.


You could try asking on usenet:sci.chem.electrochem.battery for 
information on the performance of glassmat. At least it will be 
entertaining as the theorists argue withthe practical guys

Your glass matt is rated for max C/4 or 50/4=12.5Amps, whereas DD Lead 
Acid is rated at C/10 (for longest life), so that is part of the extra 
$$$. You can do DDLA at C/5 no problemsat some life cost.

So you really need something that can give your batteries a work out at 
the needed discharge rate. I have a cactus/fscked 130AmpHr DDLA that 
charges an floats at correct voltage but is extremely hard pressed to 
run a 50W halogen.

How are these batteries wired? I am hoping that the six are in series 
and your inverter is just an oscillator. If all six are in parallel, get 
a new ups.


Basically, give it a go yourself. There is lots of voodoo about 3, 4, 5 
stage chargers for deep discharge lead acid batteries, which frankly I 
do not understand. Peeps seem keen to charge you for something they do 
not want to fully explain. When I purchased my first 130AmpHr DDLA for 
~$AUS300, I was recommend a multi-stage charger for $AUS500.

If one of the batteries is cactus, then I'd be tempted to replace the 
whole string with higher capacity lead acid. The only gotcha is in the 
charging the UPS applies as it is probably designed for glass matt.

Have fun.


For something completely different, Would you care to list exactly what 
you want to run on a UPS? and power requirements. e.g. I hope you do not 
have any screens plugged into it.






> 
>  
> 
> Thanks in advance,
> 
>  
> 
>  
> 
>  
> 
> Chris
> 
> vk6kch
> 
>  
> 
> p.s  Yes, I also have a small SLA 12V battery on the 12V rail that feeds
my
> TNC and 2m radio, but the PC running UI-VIEW still needs the UPS.
> 
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> Ozaprs at aprs.net.au
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> 


-- 
Terry Collins {:-)}}}}}
Email: terryc200605 at woa.com.au Web: http://www.woa.com.au/terryc
Bicycles, GIS, Technology, Natural Environment.
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