Re: (ET) Re: How to drive my shredder?

["John B Reinhard" <reinharj frontiernet net>]

Hi Chris & All,

I guess I don't understand Chris' math:

My various 6 Volt  batteries are all approximately 200 amp hour.
So 6 of them in series, Elec-Trak gives me 36 volts at 200 amp hours.
If I added another 2 of the 6 volts batteries at 200 Amp hours, in series, 
I
would have 48 volts at 200 amp hours.

If instead, I added a 12volt gel cell / agm / etc type battery, (which is
typically around 100 amp hour in the same size case as the 6 volt Trojan 
and
others,) in series with the 36 volt Elec-Trak pack, I would have 48 volts 
at
ONLY 100 amp hours.

Then I would have a dead 12v battery, and my main electrak pack still half
charged (with 36 v output), with another 100 ah worth of energy.

Did I miss something (like a rear battery box with 6 more 6v trojan
batteries, AND a huge 200 pound, 12 volt @ 400 ah AGM battery in your
system, or was this (your 400 ah number) a typo?

John (battery 'farmer', who recently watered & charged all 43 of his
batteries, in various electric cars & tractors, etc)

----- Original Message ----- 
From: "Christopher Zach" <czach computer org>
To: <ev listproc sjsu edu>
Cc: <elec-trak cosmos phy tufts edu>
Sent: Monday, November 15, 2004 3:44 PM
Subject: (ET) Re: How to drive my shredder?


An APC Smart-UPS 2400 is what you want. They can power just about anything.

The issue though is they typically have 4 12 volt 17ah batteries, so not
much capacity. I typically just toss mine in the back of the Elec-Trak
in the weight box and go with it for heavy chainsaw work.

When I need longer term power I do something "bad". I take a 100ah AGM
battery, put it in *series* with the Elec-Trak's 36 volts of floodeds,
and run it all into the 48 volt input on the 2400. I charge the
batteries seperately, and I watch for spread using my battery monitors,
but it gives you basically 400ah at 48 volts to play with.

Chris