Jesse,
Don't waste your time on those batteries; they are all toast. Don't
replace them with the same; four strings is poor design. Read the
article about off-grid batteries in the current Home Power, and then
sell the customer a set of 12 (or 24; either one string or two is
OK) 2V industrial cells, such as HUPs from Northwest Energy Storage
or K-series Surrettes. Size unknown. The existing full bank was 1400
A/hr if the cell cases had black covers, 1600 A/hr if the tops are
blue, to give you an idea.
BP modules from 1998 would have most likely been 12V 75W or 85W,
meaning 900-1000 watts; too small an array for that size battery
bank if the home is used full-time; OK for a seasonal or weekend
cabin.
Only with new batteries can you even tell what the inverters are
doing. My hunch is that the inverters aren't at fault. However,
given the poor quality of the original installation, they likely are
set to default setpoints, which can charge at a very high rate
(about 220A at 28.8V for two if the gennie is big enough) but won't
get batteries full (and can't equalize them), as the default
setpoints are too low. And I'll bet dollars to doughnuts the default
setpoints are in place, as the inverters have been shut down
sometime in the last 12 years, losing any original programming
settings.
You might see about getting an experienced off-gridder in your
frozen region to work with you. Maybe Darryl could consult now, then
make one trip out to set up the system once the new batteries are
in. This was the classic late-90s system with a later charge
controller upgrade, but if you have never worked with this
equipment, you're likely to set it up for a repeat failure years
down the road.
Just read Jamie's post - while his advice is spot on, of course, you
need to decide if it's worth your while. I'd be more inclined to try
his approach if the battery bank was three years old, not 12. That's
a huge amount of time spent, working with acid and an unknown set of
hazards, with at best the possibility of a few years' use. I'd
suggest that unless it's your father-in-law's cabin, and you value
the chance to hang out there for a week, it's not worth your time or
the customer's, especially given that you acknowledge having little
off-grid experience.
Allan
On 12/29/2010 6:34 AM, Jesse Dahl wrote:
Wrenches,
There is a MX60 charge controller with the system, 2 trace
inverters, and ten BP modules. Not sure the wattage of the
modules.... There was no way to get to the roof and and check.
I have only been there once, it was in October. The array was
partially shaded at 1:45pm......
The batteries (rolls 6V) are the original batteries (12 years
old....) some have visibly bulged from the freezing. There are
16 batteries, 4 sets of 4.(24 volts).
The cables were a problem in my opinion. When I was there,
only 8 batteries were being used. So there were disconnected
cables in the battery room. Cable lengths varied from bank to
bank, and they were just run across the floor.
I will post some photos that I took later today. And more
generator information, I'm in my fish house right now and don't
have my camera!!!!
Thanks for the help,
Jesse
Sent from my iPad!!!
Jesse,
It looks like you said the
battery was replaced with Rolls. If so, good choice.
Without extensive regular testing, keeping a log book,
and possessing the knowledge to do it right, you will not
really know if you are fully charging the battery to 100%
SOC. From the information in your post, it leads me to
think that this is the case.
IMO, the single most
important thing you can do for this customer is install a
battery monitor system. I recommend the trimetric. While
this will not take the place of skilled battery testing,
it will give you far more information than you have ever
had. This is where to start. You will then know how high
and low the voltage got each day. You will see how many AH
are removed and replaced each day. You will have eyes to
see your battery health like never before.
Please post the size of the
battery bank, the cables and length used to connect the
inverter and all the generator information. Perhaps we can
help more.
Larry
----- Original Message -----
Sent: Tuesday,
December 28, 2010 11:04 AM
Subject: [RE-wrenches]
Trace inverters undercharging batteries.
Wrenches,
I have been in contact with a person living off-grid in
Northern MN. She had some problems with her system and
called me. I teach a solar class at a local community
college and have been helping her in my free time (free of
course!).
Some of her batteries froze last winter and she said
she dumped out the electrolyte and put new in........ (6 V
Rolls)
Her main concern was the batteries never fully
charging. She has a very nice Kohler gen, but from what I
have been told, the Trace inverters may be part of the
problem with the batteries undercharging. I have limited
experience with off grid applications and any help would
be greatly appreciated.
Jesse
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
|
