Re: (ET) Power Inverters

[Markus Lorch <ev lorch net>]

Hi Bill,

Max made the suggestion to use a 12V inverter and I would like to second 
that. Given that it is only for emergency use I would go with an 
relatively inexpensive 12V -> 110V AC inverter, some even come with a 
charger built in. They typically have a low voltage shut off at 10.5V, 
so you could just hook it up to two 6V blocks (tap the pack) then run 
them until the inverter shuts off on its own, move the taps and hook up 
to the next two and finally the front two.

Only things to watch out for are
1) do never hook it to one full and one empty block
2) make sure you charge the blocks in pairs again with a 12V charger (or 
the built in) before you use your tractor. Otherwise you have a 
seriously unbalanced pack and the empty batteries will suffer greatly.

The UPS ideas are good, but a 36V model is very hard (if not impossible) 
to find. I myself have a big UPS with 100V battery voltage that I use 
with my electric car. I can power my heating, lights and computers for 
several days with the batteries from the electric car with the flick of 
a switch. Unfortunately we never had a big outage yet that would justify 
the investment (well the old UPS was cheap, but the wiring was quite a 
bit of work).

I would not recommend the rotary inverters that used to be original 
elec-trak accessories. I have one with 900W peak output, it could not 
start a small table saw motor and they are not very efficient. However 
they are very rugged and probably last forever, I use it to power a 
string trimmer and a small chain saw.

A completely different thing to do would be to see if you can power the 
blower with 36V DC by attaching a different motor. Your motor seems to 
be eating a whole lot of power and may be an outdated and inefficient 
way of moving the air. Maybe there are newer bldc type motors available 
that would reduce the power consumption and may even run with dc.

For example I need about 100W (less than 1/10th of your blower motor 
alone) for all heating water  and solar collector pumps plus controls so 
maybe you could switch to a more efficient furnace or blower (I am 
thinking of replacing my pumps with new ones that take only 1/5th the 
energy of the 15 year old ones, they pay themselves in 4 years by 
electricity savings alone). To put it in perspective - with 1kw 
continuous I can almost heat half my house (I currently need about 60 
kwh in gas and firewood /day plus about 2kwh for the fans and pumps/day 
- more when it gets colder).


Happy tracking

Markus


> 3. use a 12v inverter off the lead acid (a power buffer in this case) to 
> deliver 110VAC to your furnace as if the household current were available