From: ems@michael.apple.com (E. Michael Smith)
Newsgroups: sci.energy
Subject: Re: Where to get Electric Car kits?
Date: 5 Nov 92 20:04:22 GMT
Article-I.D.: michael.1992Nov5.200422.5865
Organization: Apple Computer Inc, Cupertino, CA

In article <1992Nov5.023050.17713@adobe.com> pngai@adobe.com (Phil Ngai) writes:
>In article <1992Nov5.002722.3309@michael.apple.com> ems@michael.apple.com (E. Michael Smith) writes:
>>I was thinking that when (if?) my Honda ever has the engine die, I 
>>might convert it to electric.  (It is almost exclusively used for
>>less than 50 miles/day).
>
>There was an article in the current EE Times about a guy selling electric
>cars. He didn't want to rely on new batter technology so he went low tech.
                                                          ^^^^^^^^^^^^^^^^
I wonder if this means he used 'automotive batteries' ...

>He had enough of a challenge with the power electronics.

Shouldn't have.  It isn't THAT complicated  (I've looked in the 
guts of several Ecars.  Nothing even came close to the tuner section
of a decent SW radio or an IF strip ... not to mention the switching
power supplies and motherboard of a PC ...  I've built or fixed  one 
or more of each.)

>Anyway, he claims a set of batteries lasts 3500 miles. That's not per
>charge, that's it. Period. 

Let's see ... 100 mile range, 35 cycles, ... yup, sounds like he used
automotive batteries.  They would be dead meat after 35 deep cycles.

Ni-Cds should be good for 1000 cycles, or 100,000 miles, if handled
well.  Deepcycle cart batteries (NOT RV batteries) should be somewhere
in between the two ... figure about 30,000 miles.  Or three years at
my present rate of usage for the Honda (about 10-12k miles/yr).

I'm willing to buy a set of 'golfcart' batteries and replace them in
the year 1996 with Ni-hydrides ...  Then again, my Honda may not have
it's IC engine die until 1996 ...  At 230k miles on the odometer, it
still doesn't use oil between oil changes and has no detectable problems.
Maybe I'll buy a junker ;-)

>That would be about two or three months for you.
>Of course, it's always possible someone dropped a digit or two.

I suspect that they either dropped a zero from 35,000 miles OR that the
guy just used the wrong kind of battery when he went 'low tech'.  Even
'deep cycle' RV batteries don't stand up to the kind of usage a car
has.  You need the 'golf cart' batteries...

>>If it was 'only' a couple of grand to bolt in a {motor,batteries, controller,
>>etc.} I'd be willing to try it ... 
>
>You're talking about a lot of fancy expensive power electronics. Cost may go
>down eventually but right now a couple of grand seems very very low.

BIG power electronics, yes.  But fancy?  A 120 VDC battery stack could 
be charged from a large bridge rectifier and a resistor (with a LOT of 
personal monitoring!).  The 'power electronics' CAN be as simple as a set of 
relays to cut in more or less of the battery stack.  (DUMB way to do it,
I know, but it does work for a 'toy' system...).  I've seen a system
that used old solenoid relays to give a (8 or 10?) position 'gas pedal' 
by various combinations of parallel and serial battery connections.  
Coupled with a 4 speed transmission it gave all the speed control needed. 

Not everything needs to be a SunRaycer ...

(I know, nice complicated SCR rich motor control circuits with micro
processor control are much more efficient ... but I'm talking about
building a 'garage mechanic delight' toy car ...).

-- 

E. Michael Smith  ems@apple.COM

'Whatever you can do, or dream you can, begin it.  Boldness has
 genius, power and magic in it.'  -  Goethe

I am not responsible nor is anyone else.  Everything is disclaimed.