[RE-wrenches] Info On 2 V batteries Please

[bob ellison]

These batteries can take a 2000 or so cycles to 20% dod before they are worn
out.
Both numbers could be the 6 hour rate, it varies with electrolyte strength.
Somewhere between 1.265 and 1.285 SG, some hi acid cells are 1.325 SG.
The 24 means 24 cells, the 85 is the 85 AH plates and the 13 means 13
positive plates. Those will weigh 90 - 100# for each cell.
Can send you more info if you want.

Got to run,
Bob Ellison

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Parrish,
Peter
Sent: Tuesday, November 27, 2012 4:31 PM
To: RE-wrenches
Subject: [RE-wrenches] Info On 2 V batteries Please

We recently purchased a battery powered forklift, with 24 ea. 2V batteries.
Approximate dimensions: W=5", L=6-3/16", H=~21" (hard to tell). Enersys is
stamped on the top.

The battery supplier claims the batteries are "24-85-13" but this refers to
a 24V battery as far as I can tell. He also claims that the batteries are
rated at 510-550 A-hr. I am assuming that the lower number is for 6 hours
discharge.

I would like to know more about the batteries. Also, how to discharge /
charge them. Should they be run down to 20% SOC and then fully charged? What
if we don't use the forklift for a week at a time?

Based on my experience of using AGM batteries, it would seem that the Bulk
charging rate should be some percentage (e.g. 20%) of the 6-hour ampacity,
then there is a constant voltage absorption charge (e.g. Vabs=2.385 V), and
a switch to Float when the charging current drops to some low percentage
(e.g. 0.5% of capacity), and the Float voltage being 2.125 V. Again
everything at 25 deg C. It seems like the forklift guys like to refer
everything to a 6 hour capacity, which may be related to the maximum typical
daily usage.

What is the relationship between Voc and SOC after resting the battery for 6
hours at 25 deg C?

Thanks in advance for your help, guys.

- Peter Parrish

Alternative Energy Department
College of the Canyons
peter.parrish at canyons.edu
O: (661) 362-3888 C: (323) 839-6108
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