[RE-wrenches] DC Fusing/Breakers for Battery Circuits
Ray Walters
ray at solarray.com
Fri Feb 7 11:39:09 PST 2014
I started using automotive SAE rated resettable circuit breakers like these:
http://www.delcity.net/store/Hi!Amp-Surface-Mount-!-%3Cbr%3EManual-Reset-%28Switchable%29/p_193073
I'm only using these on smaller stand alone (non NEC) off grid systems,
but they are sealed, and allow protection right at the battery. Price
is decent too.
If used as supplementary protection, (in addition to a listed DC
breaker) the inspector might let you use these, since the batteries
aren't usually UL listed either.
I've seen folks use Class T fuses right at the battery terminal, which
in some ways offers superior protection, but seeing corrosion eating up
around the outside of your expensive fuse is concerning.
I also agree with Dan on battery box construction, plywood isn't so
good, steel corrodes..... it seems both battery box construction and OCP
at the box for flooded cells is just not really there.
Plenty of good choices (Outback, Midnite) for sealed batteries.
We really could use a battery that had integrated OCP that was sealed
against corrosion. It could just be a class T fuse with an anti
-corrosive seal with a holder integrated into the positive terminal.
(the things I dream of at night....)
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 2/7/2014 10:26 AM, Dan Fink wrote:
> Does anyone have any elegant solutions to this? It's really time
> consuming and ugly to run big parallel battery string wires *out* of
> the battery enclosure to class T fuses, then back into the battery
> box. It looks very ugly and DIY, and in conduit adds a few hundred to
> the install cost just for labor. The Class T fuses and blocks
> themselves are not particularly expensive.
> I have been recommending parallel fusing on battery banks of 2x8 L16s
> and over now, after a nearly tragic incident with a bad cell that
> shorted. The (perfectly legal) wooden battery box made the fire much
> worse. A pet peeve of mine.
>
>
> Dan Fink,
> Executive Director;
> Otherpower
> Buckville Energy Consulting
> Buckville Publications LLC
> NABCEP / IREC accredited Continuing Education Providers
> 970.672.4342
>
>
>
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