Did this customer check the voltage of the individual batteries/cells?
Maybe there is a weak cell developing. Sometimes EQing can take a long
time. I do not "buy" that batteries need to be cycled to stay healthy.
Todd
jay peltz wrote:
Hi Robert,
When you mention cycling batteries, are you saying that batteries in a
offgrid system that are being cycled 15-25% a day should be cycled
even deeper than that?
Thanks,
jay
peltz power
On Aug 1, 2008, at 8:36 PM, robert ellison wrote:
A couple things that I haver noticed in the past, sometimes batteries
like to be cycled, shut off the controllers and run them down, then
charge them up fully and then give them an eq charge till it comes up
the peak voltage and hold it there as it (sometimes) slowly rises.
Any of these thoughts are superseded by Jamie if he has any thoughts.
Also, if you have not given them an eq in a while it might take
longer than the available solar time has to get them to the top and
hold them there..
Have the controllers settings changed?
Bob
On Fri, Aug 1, 2008 at 10:18 PM, Allan Sindelar
<[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Wrenches,
In late 2003 we installed a 24V set of Rolls-Surrette 4-KS-21PS
6V 1104 A/hr batteries in the off-grid system of a long-time
client. The client's system had a democracy array of around 800
watts of tracked PV. In early 2005 we added 1,280 watts of
additional PV, and the client hasn't run the generator since; the
system rarely drops below 80% and fills to 100% most days in
sunny New Mexico. Batteries are located in a basement, so
temperatures stay relatively constant, although it will vary
slightly seasonally. MX60 controller is temperature compensated,
with 29.6 VDC bulk and 31.4 VDC EQ set points.
The problem is that the client reports being unable to achieve
previous EQ voltages, and this inability appears to be a new
development. The system is otherwise performing well. As the
client is sharp and pays close attention to the system's
operation, I'm not ready to blame user ignorance (with one
possible exception; read on). This may be an issue of seasonally
warm temperatures, but I'm not sure this would explain the full
0.4 VDC reduction in voltage. I told him that I would post his
problem to this list, and also request advice from Surrette Battery.
Here is the client's description of the symptoms:
I'm concerned that I am unable to equalize batteries at this
time. Up
until June of this year the Tri-Metric readings during equalizing
indicated
holding voltage at 31.1, with maximum amps gain of around 52.
Three weeks
ago, when set on equalize, the maximum voltage reading was 30.7,
with
maximum amps of 46; this was reached around noon, and by around
1:30 pm
voltage/amps began its typical afternoon drop-off. I attempted
equalizing
on two other occasions since then--the last time this past
Saturday, with
clear skies up until mid-afternoon--but having the same results.
So, the
question is: are my batteries beginning their decline? We've had
this set
for 4 1/2 years, so it would seem a bit too early for this, given
that these
batteries are expected to last 7-10 years.
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