<div dir="ltr">This chart from Trojan is very customer good education. Battery electrolyte is very close to water at low SOC.<div><a href="http://www.trojanbattery.com/pdf/WP_DeepCycleBatteryStorage_0512.pdf">http://www.trojanbattery.com/pdf/WP_DeepCycleBatteryStorage_0512.pdf</a><br></div><div><br></div><div>Also, note that many MPPT charge controllers won't "wake up" and start charging, even on a sunny day, if battery voltage is below 9.5V +/-, unlike some older PWM units without the fancy computer inside which will wake up with the sun. So the solution is to "jump start" the voltage, even if you have to center tap charge for a few minutes to raise voltage before the controller wakes up and the sun can take over (photo, center tapped 24v battery bank with 12v wakeup call).</div><div><br></div><div>I'd give saving the battery bank a shot unless you can see physical damage inside or out from the freezing. In any case, you'll know very quickly when you start charging if it has caused an internal short. In my experience, good batteries can take 0%+/- SOC a few times--they have certainly lost a lot of capacity but might still have some life in them. If physical damage occurred, send them to recycle center.</div><div><br></div><div>Good luck!</div><div><br></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><span style="font-size:12.8000001907349px">Dan Fink</span><div style="font-size:12.8000001907349px">Adjunct Professor, Ecotech Institute</div><div style="font-size:12.8000001907349px">IREC Certified Instructor™ for: </div><div style="font-size:12.8000001907349px">~ PV Installation Professional</div><div style="font-size:12.8000001907349px">~ Small Wind Installer</div><div style="font-size:12.8000001907349px">Executive Director, Buckville Energy</div><div style="font-size:12.8000001907349px">NABCEP Accredited Continuing Education Providers™<br><a href="tel:970.672.4342" value="+19706724342" style="color:rgb(17,85,204)" target="_blank">970.672.4342</a></div><br> </div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Thu, Dec 3, 2015 at 7:00 AM, Feather River Solar Electric <span dir="ltr"><<a href="mailto:info@frenergy.net" target="_blank">info@frenergy.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Hey Folks,<br>
<br>
I came across an off-gridder yesterday whom was getting zero
support from the dealer he had purchased his small system from, self
installed, batteries in a lightly insulated box outside. When I
inspected the electrolyte levels I discovered it was frozen in some
cells, the voltage of the 48 volt pack was ~8 volts, I didn't check
individual batteries due to these facts...I'd seen "enough".
Recently temps have been in the high teens, though we are back up to
low 30's.<br>
<br>
He does not have a genny or battery charger! I have a DC
genny which I could use to charge these batteries but should I waste
my time and his money trying to save them? Others' experience with
this situation?<br>
<br>
TIA,<br>
<br>
Bill<br>
<img alt="" src="cid:part1.08010806.07030708@frenergy.net" height="103" width="306"><span class="HOEnZb"><font color="#888888"><br>
<pre cols="72">--
Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
<a href="tel:530.284.7849" value="+15302847849" target="_blank">530.284.7849</a>
CA Lic 874049
<a href="http://www.frenergy.net" target="_blank">www.frenergy.net</a>
</pre>
</font></span></div>
<br>_______________________________________________<br>
List sponsored by Redwood Alliance<br>
<br>
List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br>
<br>
Change listserver email address & settings:<br>
<a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" rel="noreferrer" target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br>
<br>
List-Archive: <a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" rel="noreferrer" target="_blank">http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html</a><br>
<br>
List rules & etiquette:<br>
<a href="http://www.re-wrenches.org/etiquette.htm" rel="noreferrer" target="_blank">www.re-wrenches.org/etiquette.htm</a><br>
<br>
Check out or update participant bios:<br>
<a href="http://www.members.re-wrenches.org" rel="noreferrer" target="_blank">www.members.re-wrenches.org</a><br>
<br>
<br></blockquote></div><br></div></div>