Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!think!eplunix!raoul
From: raoul@eplunix.UUCP (Otero)
Newsgroups: sci.electronics
Subject: Re: Electric cars?  Start with wheelchairs.
Message-ID: <774@eplunix.UUCP>
Date: 22 Aug 89 16:42:37 GMT
References: <3659@internal.Apple.COM> <5481@ttidca.TTI.COM> <21503@cup.portal.com>
Distribution: usa
Organization: Eaton-Peabody Lab, Boston, MA
Lines: 30

In article <21503@cup.portal.com>, wordy@cup.portal.com (Steven K Roberts) writes:
> I can't help but wonder why nobody ever mentions solar power in 
> discussions like this.  

Sudden images of Cutter John and the crew of the Star Chair Enterprise,
wheeling actoss Bloom County at Warp 87.... In real life, though, wheel
chairs are unwieldy enough without solar panel umbrellas. The point of the
problem is to make things easier to handle and portable, not make it larger
and more unwieldy. 

I liked the one gentleman's idea about different connectors for use and
recharging, linking them in parallel persus series. But didn't the original
poster mention that the user had little upper body strength or mobility?
It's kind o' awkward to pull apart good sealed connectors.

So, why not put in a DPDT relay at the recharge circuit that switches the
poles of one of the batteries? The relay only goes on if there is 12 V
recharge voltage. And maybe another relay at a 110 volt source, to connect
that converter/recharger instead. 

And there is a very good reason not to recharge one battery at a time: A
deeply discharged lead-acid in series with a fully charged one can have a
reverse charge put on it by the charged one. This is very bad for
lead-acids.... Manufacturers *laugh* at warranties if you try this.

-- 
			Nico Garcia
			Engineer, CIRL 
			Mass. Eye and Ear Infirmary
			eplunix!cirl!raoul@eddie.mit.edu