On 2014-03-01, wrote:
On Sat, 01 Mar 2014 09:53:39 -0800, Gunner Asch
wrote:

On Sat, 1 Mar 2014 11:13:56 -0600, "RogerN" wrote:

[ ... ]

Also, something I was interested in for boat batteries. Get a gasoline
small engine and mount an automotive alternator, then you can have a
portable battery charger that should be capable of some fairly high current.
For Gunner's 8V batteries, I read about modifying the voltage regulators for
alternators (the kind that have external regulators). IIRC, the basic idea
was to control the output by controlling the power going to the rotor. That
way the alternator, with the right voltage regulator, could be used to
charge 8V batteries on up to 48V golf cart or fork truck batteries.

http://www.smartgauge.co.uk/alt_mod.html
http://www.madelectrical.com/electri...witworks.shtml

RogerN


Thanks for the links!!

Gunner
Inserting a few diodes in the "sense" lead to the regulator will
raise the charging voltage 3 silicone diodes will raise the voltage by
aprox 2.1 volts - close enough to charge an 8 volt battery with a 6
volt regulator.

Hmm ... if an 8V battery were a *true* 8V -- yes. However,
since the 8V lead-acidej battery is four nominal 2.2V cells, that will
really be 8.8V charged, and closer to 9.6V under charge, depending on
temperature, so you want to boost that regulator's output by 3.6V --
about five diodes total.

And it would be nice to have a current limit in the regulator
chip too, just to be safe. :-)

Enjoy,
DoN.

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