Update on my investigation:
I visited the customer's house yesterday to set up a pulse charger. Much to
my surprise the three batteries that originally registered negative voltage
are now reading positive. Does this make sense - are batteries able to
shift between negative and positive voltages at
If a battery gets discharged to far it goes into what's called reversal The
positive actually becomes negative and vice versa
When you start charging them it will go back to normal
Bob Ellison
> On Dec 19, 2014, at 9:48 AM, Corey Shalanski
> wrote:
>
> Update on my investigation:
> I visite
First time I ever saw one of the bank of 80 cells are just about put me in a
panic
Had no idea they could do that either
Bob Ellison
> On Dec 19, 2014, at 9:48 AM, Corey Shalanski
> wrote:
>
> Update on my investigation:
> I visited the customer's house yesterday to set up a pulse charger.
Keep and eye on the batteries... when they allow this far of a discharge and go
into cell reversal often they are much weaker than the rest of the batteries.
I would have the customer cycle them once or twice a week to the 85-90% SOC,
just to test how healthy the battery bank is.
To do so, di
Corey,
The reason a cell or a battery in series will reverse polarity is due to
that cell having a lower capacity than other cells. For example, you
have a string of 100AH cells. One cell only has a capacity 70AH. If you
discharge the string more than 70Ah, in order for that cell to continue
Here's a drawing to illustrate. When the 70AH is drained, the string
voltage will drop because that cell will go to 0 volts. Continued
discharge will reverse the cell voltage. When charging, the 70AH will
get full first and be overcharged.
On 12/19/14 9:44 AM, Larry wrote:
Corey,
The reason
Hi:
This cell reversal ability of lead acid batteries gives good perspective
on just how much you can mistreat them and beat them up and still have an
expectation of "recovery".
Lithium cells on the other hand without a full range of protections would
have long since filled the home with all k
When I had batteries reverse polarity they quickly turned around but
never had their capacity after.
2nd, that is a clear indication of a DC drain that can kept draining all
the way to zero. The strongest batteries keep giving voltage, while
weaker batteries give all they have and become resist
I find it really curious.
I've been dealing with batteries for almost 20 yrs. I've seen so many dead,
flat batteries, systems etc I can't count them all.
But I've yet to find a reversed one.
I understand the process.
I'm trying to understand how he could get multiple reversed batteries at one
I have only seen this in cases with DC loads and no LVD. Inverter
systems without DC loads would never exhibit this behavior, unless there
was a short in the battery cabling or bad cells.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design E
I have installed/serviced thousands of battery based systems, I have not
seen any reversed cells either, but I know how it happens.
Here's a thought on what could cause multiple lower capacity cells in a
bank. From the moment a battery is not being charged, including newly
assembled batteries,
That's the reason it is so essential to get as fresh a batch as possible and
make sure all are fully charged before installation.
Bill Dorsett
Manhattan, KS
From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Larry
Sent: Friday, December 19, 2014 7:07 PM
To:
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