[RE-wrenches] High specific gravity

[Dan Fink]

I generally use specific gravity as a way to measure the differences
between individual cells, batteries and strings, not relying on the exact
reading, to get an idea if there are problems (usually connections) in part
of the battery bank. You also said SG readings were all over the place.

I'd first pull put my old temperature compensated float hydrometer and
check it against the refractometer for a few readings.


Dan Fink
Buckville Energy
Otherpower
NABCEP / IREC / ISPQ accredited Continuing Education Providers
970.672.4342




On Tue, Aug 12, 2014 at 7:54 PM, Mac Lewis <maclewis1 at gmail.com> wrote:

> Hello wrenches,
>
> I just went on a service call for a new client.  He had a bank of 4 year
> old Interstate L16HCL batteries, 2 strings of 8, 48V system, 840Ahr.  We
> went through the batteries and got specific gravity on all of the cells
> post-equalization.  I was a bit surprised to see some very high numbers ie
> over 1.32 for the specific gravities (higher than my refractometer goes).
>  The specific gravities were all over the place, but I haven't seen numbers
> this high.  I don't have a great explanation.  He has a stacked 3648 VFX
> Outback system, and the set-points were 58.8V Absorb for 2 hours, and 62V
> Equalize for 2 hours.  He has a decent amount of solar (about 3400W) and a
> 1000W wind generator.
>
> Any ideas why the specific gravity is so high on some cells?  Also, is
> there anything wrong with having SG this high, post-equalization?  For this
> very standard battery, what settings do you go with (Bulk, Absorb, Float,
> Eq, and times for Abs and Equalization).
>
> Thanks in advance
>
>
>
> --
>
>
>
> Mac Lewis
>
> *"Yo solo sé que no sé nada." -Sócrates *
>
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