Re: Battery Boxes...What One Company Designed

[John Beardmore <wookie@xxxxxxxxxxxxxxxxxx>]

In message <1126911322.406213.125620@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Too_Many_Tools <too_many_tools@xxxxxxxxx> writes

>I ask what voltage because I can wire it in different arrangments...it
>was wired for 12v.
>
>I am asking because as you point out there are different inverters out
>there.

But only you know what they cost YOU.

Personally I have done a lot of mobile stuff on 24 volts because that's
what trucks use.  I don't like 12 because the current requires huge
wires, though I've done a bit of that.  If it was for home / stationary
use I'd expect to see some efficiency advantages by going to higher
voltages, but if you charge from PV for example, will you be able to get
say a 96V OPT regulator off the shelf ?  And what if one battery or PV
in a string fails ? Probability goes up as strings get longer.  Lots to
consider.


>I have a number of surplus UPS inverters that I may use...I am still in
>the design stage on this subject.

Good...


>The APC Smart/Matrix UPSes are sine wave, are CHEAP and large enough to
>be worth using. The downside is that UPS inverters usually have higher
>idle current requirements that dedicated inverters available on the
>market now. I have yet to do the tradeoffs with a market survey. Any
>suggestions you can offer will be appreciated.

None really.  The inverters we have used have been cheap, modern, fairly
efficient, fragile, small, switching technology, square wave out and
nasty, or have been hugely heavy, inefficient thyristor fired 50Hz 1960s
technology with massive transformers and sin wave output.  All down to
what has come out way.

We also have a huge, and I suspect fairly inefficient 7kW UPS inverter
lurking around but there isn't much point in telling you about that.
One day it will come in handy though.

But given the price of modern inverters, is it worth your just going out
and buying what you need when you know what you need ?


Cheers, J/.
--
John Beardmore