[sdiy] inverter

[Roy J. Tellason]

On Wednesday 12 July 2006 01:09 pm, bill bigrig wrote:
> howdy,
>
>  Come to think of it, get yourself a BIG dumptruck or Caterpillar battery.
> If the cell connectors are not exposed, you can drill one hole EXACTLY
> halfway between the posts on the opposite side of them. About 1/8" to 1/4"
> down, you will hit lead or some other metal. Put in a screw and there is
> your 6 volt tap. Now, on the post side you will find 2 cell connectors about
> 1/3 of the length from each post. these are your 2 and 10 volt taps. Go back
> to the side with the screw in the center of the length of the battery and
> measure out 1/3 of the length and this is where you'll find your 4 and 8
> volt taps. If you draw 6 equal cells on the top of the battery this will be
> easier to see. If you don't find the cell connectors, just seal the hole
> back up with silicone. 9 volt stuff will do fine with either 8 or 10 volts.
> Casio and Yamaha at 7.5 should do fine on the 8 volt post. A car stereo
> amplifer will give you your volume. As I said before, for bipolar, use 2
> batteries. Anything that runs 15 volt bipolar should do OK with 12V. After
> your done, unhook the batteries, wire them in parallel and AFTER you start
> your vehicle, hook them up to the vehicle battery. They will charge merrily
> all the way home.

Not recommended,  for a couple of reasons...

First,  you don't want to discharge portions of a battery to different levels, 
they'll never charge up equally afterwards.

Second,  newer batteries (most of them anyhow) won't have cell-to-cell 
connectors that you can get to,  they go _through_ the cell walls because the 
shortest connections give the lowest resistance,  and are therefore below the 
level of the electrolyte.  You drill a hole that has the effect of allowing 
connection between two cells and you've just effectively removed one whole 
set of plates from the battery,  losing a cell in the process,  and trashed 
it.

Not to mention this voiding any warranty you might have.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
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