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Re: Fwd: battery management and power distribution system design 2 (message got trunc

gulabrao ingle wrote:
> What kind of battery management system or power distribution system
> has be constructed in order to meet the following criteria?
>
> 1. Instead of all batteries discharging equally together, can there be
> a system in which small sets of 2-3 batteries discharge more than
> the rest of the pack without the overall pack voltage becoming down?

As a rule, you *want* all batteries to discharge equally, because this
maximizes your range and battery life. What is the reason that you want
to discharge them by different amounts?

> 2. These small sets, once discharged, are disconnected and then are
> charged by an external means like an alternator or solar panels.

This is possible. But the normal method would be to leave the batteries
connected, and simply charge them in place with an isolated charger or
equivalent device.

> 3. Once fully charged, they are again connected to the main pack, and
> another small set which has become discharged takes their place
> at the charging port.

Again, it's possible. I tend to think you wind up with a large number of
high-current switches, which makes such an approach more expensive and
less reliable than using isolated chargers.

> 4. For this setup which battery technology is more suitable li-ion
> ni-mh pb-acid?

It's hard to tell. Any method that results in deeper discharges for each
battery tends to shorten that battery's life, regardless of the chemistry.

> Also, what cost will be incurred in it and can it be made at home?

You would have to design and build the system before such a question
could be answered. The best way to experiment to see if such a system
would actually work would be to build one using switches, and manually
operate it to achieve your desired result. Then compare the results to a
"control" system that doesn't do it to see if you method is any better.

If it proves better, then set out to automate the process.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
 
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