On 19/10/2010 1:52 PM, Arby bernt wrote:
> Brian at Thunderstruck has been using a cool balancer for some time.
> He uses a
> Zener diode connected in series to a 12v automotive lamp across each
> battery in
> the string. When a battery reaches voltage before the others, the lamp
> will glow
> and shunt some of the energy from over-charging the high cell. It also
> provides
> a nice indicator of a weak cell in a string.
G'day All
I've not been following this thread properly, just skimming it, but a
little correction, they are a shunt regulator invented by Lee Hart (or
at least a version of them), more information can be found here:
http://www.evdl.org/pages/hartregs.html
The lamp is a low voltage lamp, as a 12V lamp would never see enough
voltage to light up properly. The zeners are two, set up as per the
instructions http://www.evdl.org/docs/zenerregs.pdf .
They soft-clamp the top voltage that the battery sees, so that in a
series string the battery that hits full first gets some bypassing so
that it doesn't get hurt by over-voltage (not needed with wet cell
batteries, as the gassing performs the same function, but necessary with
sealed batteries).
If you charge a series string of batteries, somehow you need to make
sure that you do not over-charge the good ones that reach full first,
either by individual chargers or individual regulators. Individual
chargers are best, but ONLY if you have means to tell if one has stopped
working, because if that happens one battery has not been charged, and
the rest were, so the under-charged one gets killed very quickly if you
try and use the series group of batteries. If you do not have means to
tell if an individual charger doesn't work, then best to use a
whole-pack charger with individual regulators (since the probability if
a regulator fails is that the individual battery is hurt a little by
over-charging, rather than hurt a lot by reverse-voltage).
Hope this helps
Regards
[Technik] James
No comments:
Post a Comment