1. For paralleling battery packs (which I have done for long-term maintenance charging, and which I have done for adding a second string of six batts on a "back porch" on my snow-throwing set-up), put in fuses. I put fuses in most every circuit I build because I am such a puddin' head and I do things like (though not exactly this one yet) short the pins of double-male connectors by dropping them against a conductor. I have to protect me from ME, y'know. 200A electric vehicle fuses are my protection of choice.
2. and for the point about different capacities of different packs, for both the sake of charge and discharge, I have always relied on the fact that packs, as long as they are in shape to provide service, will give (doing work) and get (for charging) current according to their voltages, and so I have never worried about different packs' ages or the resulting difference in capacities. They go up and come down together, and if one pack is weaker than another, it just winds up delivering less electrical work than the other. (I do pay attention to different charging; sometimes I have to separate the strings to top up the lagger.)
It's snowing like crazy here west of Boston. Fluffy stuff. Mmmmmm.
On 12/13/07,
David Roden (Akron OH USA) <etpost drmm net> wrote:On 13 Dec 2007 at 11:01, Thompson, Geof wrote:
> Thoughts?
Whether your barn has a separate service or is a subfeed from the house
main, I'm not sure there are any code-approved ways to backfeed your main
house service through the barn service. In order to do this safely and to
code, you may have to trench in a separate line to a transfer switch ahead
of the main house panel (or the sub you're using to feed the loads you want
on backup power).
Regardless, with all the ETs you have, you should have literally DAYS' worth
of backp power there. However, connecting them all in parallel might be
troublesome because they differ in capacity and condition.
I definitely would recommend against doing this with double-end dryer
cables. Much too easy to accidentally short the pins on the free end after
the other end is plugged in. The result could be a real disaster.
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