Re: Device to open a circuit when a voltage is released?

From: Bruce W.1 (no_at_email.com)
Date: 03/19/05 

Date: Sat, 19 Mar 2005 00:43:19 GMT

mike wrote:

> All you need is a comparator and a relay.
> Only you know your application.
>
> BUT.
> Think about better than half volt resolution.
> Half a volt at 1V is BIG.
> Even on a 10-cell pack, half a volt can mean the difference between OK
> and smoked battery. Then you need to figure out the value to set.
>
> FWIW, I've been plotting charge curves on various kinds of batteries.
> Depending on age, history, size, type, the peak voltage of the charge
> curve varies all over the map. The only cells I've had terminate charge
> on overvoltage were those seriously worn out.
>
> It's much safer and less stressful on the cells if you use some kind of
> slope termination with a secondary safety based on temperature.
> mike
>
===================================================

A voltage comparator and a relay. I like that idea. Off the same
regulated power supply that's running the charge or discharge circuit I
could make a voltage divider with a rheostat.

But what if the voltage is going up (charge) or down (discharge)? Guess
I should read-up on voltage comparators.

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