[RE-wrenches] Testing new batteries

Rob Shappell rob at nwes.com
Fri Mar 25 06:35:32 PDT 2011


With all due respect Larry, you must add acid, not water, if you know acid
has been lost. Otherwise you can charge, charge, charge and never reach full
SG.

 

Rob Shappell

Northwest Energy Storage

Solar-One Batteries

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Starlight
Solar, Larry Crutcher
Sent: Thursday, March 24, 2011 8:12 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Testing new batteries

 

Benn,

 

First off, there is never a reason to add acid. The acid/water mixture is
very specific and should not be changed.

 

>From the moment a battery has been activated (electrolyte added), it is in a
discharge mode. The sulfuric acid in the electrolyte starts to be absorbed
into the plates (electrochemical process) creating lead sulfate. All new
batteries need to be initially charged to reverse this. Only then can you
get an accurate SG base reading to record in the log book.

 

New flooded battery charging process:

Start by charging the new battery at a relatively high voltage, about
2.47vpc @ 77 degrees, until the current drops to about 0.5 amps per 100AH
capacity. As long as the plates are covered, you do not need to add any
water during this process. Turn the voltage up to about 2.6 volts per cell
for at least a couple hours. You will notice heavy gassing so make sure they
are vented well. Let batteries rest a while and take your SG reading. Only
if necessary, add water to the proper level. Long battery life note: Do not
discharge new batteries very deep until they have been cycled about 10 to 15
times.

 

About battery manufacture dates: 

Too often we have received batteries that have set for many months after
manufacturing. We return these because the amorphous lead sulfate ions may
have formed bonds to the plate that are (or may be) irreversible. This same
effect is caused by undercharging a battery for long periods and it usually
leads to premature failure. Any flooded battery setting for over 30 days
should be fully recharged.

 

To answer your question about liquid volume, the plates are absorbent. They
absorb acid while discharging and the acid is recombined with water when
charging. So the level is in constant flux. That is why you should not add
water to a discharged battery except to cover the plates; charge it first.

 

Much more than 2 cents but that's just me.

 

Larry Crutcher
Starlight Solar Power Systems
www.starlightsolar.com
928-342-9103

 

----- Original Message ----- 

From: benn kilburn <mailto:benn at daystarsolar.ca>  

To: Wrenches <mailto:re-wrenches at lists.re-wrenches.org>  

Sent: Thursday, March 24, 2011 11:12 AM

Subject: Re: [RE-wrenches] Testing new batteries

 

Mick n' Nick, 

Thanks guys.  I shoulda mentioned that the date code says they were mfgrd
the 7th week of 2011 and the one exception, the 8th week.  So they haven't
been sitting too long.

 

I have been in contact with the mfgr, and of course i will take their advice
over anyone else's (gotta keep the warranty valid), but you cannot deny the
value of the hands-on experience and insight from this list.  They said to
add distilled water after the initial charge, which is why i was only
"considering" adding acid.  I have asked about adding acid rather than
water.  Waiting for reply.....

 

Mick, you mentioned that the electrolyte levels may level once all batteries
are at equal SOC.  Can you elaborate?  Do the plates become more or less
'absorbent' or does the chemical reaction change the volume of the liquid.
I will watch this closely.

 

cheers,

benn

DayStar Renewable Energy Inc.  

benn at daystarsolar.ca

780-906-7807 

HAVE A SUNNY DAY 

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