From: damon henry
<I have been quite happy until now with using a 14 volt house battery
and no DC/DC<
There are some good points to your set up ,, The smaller you
traction pack the more sense a house battery makes and your set up
lets you have the extra voltage to keep light bright.
> 19 - 20 volts which is too high for the hairball input, >
That is high ,, You could have a relay that would cut out the house
battery when charging . if the house charger is in the car and runs
off the ac use a relay powered by the ac input . Could even use the
key to switch the relay but that would be a bit tricky as you need
power to run the relay.
>so I need some way to make sure the hairball never sees my full charging
>voltage or too high of a surface voltage after charge.<
This would be a bit easier as the total load ( with contactor) is only
a few amps . A diode will drop .7 v so 3 or 4 in series on the wire
going to the inputs would drop you voltage enough .
> I really like my higher voltage battery as it means my lights are bright and
> wipers run briskly, but so far I have not thought of a solution that I really
> like to make sure the hairball doesn't see too high of voltage while
> continuing to use my extra cell setup.
Any great ideas out there? I am looking for something that is low to
no cost, and fairly fool proof. I'm not sure what the actual upper
limit is, but for safety sake I would like to set 15 volts as the
absolute upper limit.<
You'd need to use diodes that could handle the amps and maybe a heat
sink. Another way might be to power the hair ball and contactor with a
small dc to dc like the lab top computer power supply you see for 10
to 20 dollars that are marked 100 to 240 v input . Your key would have
to turn it on so you'll need a relay to do that but you would have
steady controller power . If you do it this way you might want to
test the lab top supply to make sure it dosen't over shoot the voltage
when starting up as the load may be to low when first powering up .
>Some ideas I've considered.
Fully disconnect the hairball when the key is off and don't charge
house battery with key on... Not very fool proof plus I still may have
an initial surface voltage issue and I don't know if the hairball
likes to be completely disconnected or not.<
I've wonder about this also as the hair ball uses a few millamps and a
car sitting for a few weeks could have its house battery drained.
>Connect my fuse box to only 10 Nicad cells and wire a separate circuit for my
>head lights and wipers with extra cells in series. This idea is not bad, it
>could lead to some house battery imbalance, but I think that would be fairly
>easy to manage. Many times I do not use my headlights or wipers.<
I would go this way to easy to imbalance the house battery
> some kind of voltage regulator in the circuits going into the hairball.
Yes with a zenor diode and power transistor and you have a voltage regulator ,
Steve Clunn
Merging the best of the past with
the best of the future.
www.Greenshedconversions.com
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