off grid power supply question, batteries, etc.

CamperMan

OK,

I have 10 x 6v 160 amp batteries, 1 x 24v 1400 watt inverter / charger, 2 x 140 watt 12 v solar panels and a diesel generator,

to get maximum juice from the batteries, it would be better to have them connected up as 12v, is it possible to use a 12v to 24v stepper between the 12v battery bank layout and the 24v inverter?,

if I use the batteries in the 24v system I can only use 8, this will only give me 320 a/h, if I connect the batteries up as a 12v system I can use all 10 of them giving me 800 a/h hence the question about the 12v to 24v stepper, would this work?

Thanks

drunken_munky52

The inverter is rated for 24V input. Is there any particular need to use the a 24V inverter? You said "it would be better to use 12V", so why not use a 12V inverter instead?

You understand that connecting batteries in series increases voltage and in parallel increases current. So 2 strings of 4 gives you 320Ah @ 24V while 4 strings of of 2 gives you 640Ah @ 12V. You still are left with 2 un-used batteries, am I correct?

In regards the stepper, that would be a DC to DC converter. I dont see how this would cause any issue when inputting into your inverter. All the inverter "sees" is DC current, and does not discriminate weather this is from a battery or via a power supply.

CamperMan

I got the 24v inverter / charger cheap, it's a quality one, not like the cheap Chinese rubbish, the equivalent 12v inverter chargers would have cost me 5 times the amount.

quentingargan

CamperMan wrote: »

OK,

I have 10 x 6v 160 amp batteries, 1 x 24v 1400 watt inverter / charger, 2 x 140 watt 12 v solar panels and a diesel generator,

to get maximum juice from the batteries, it would be better to have them connected up as 12v, is it possible to use a 12v to 24v stepper between the 12v battery bank layout and the 24v inverter?,

if I use the batteries in the 24v system I can only use 8, this will only give me 320 a/h, if I connect the batteries up as a 12v system I can use all 10 of them giving me 800 a/h hence the question about the 12v to 24v stepper, would this work?

Thanks

If you are taking 1400 Watts into our out of the inverter charger, at 12V, that is going to be over 100A. Finding a cheap DC DC converter rated to this sort of current isn't going to be easy.

I would prefer to go with a 24V system in any event - for the power used, your current is halved, and your cable size can be a quarter of what it needs to be for 12V, unless the wire distances are so small as to be insignificant. You will need to use stranded wire on all DC circuits, rather than solid copper.

As regards the two left-over cells, you could possibly get a smaller DC DC converter to charge these as a 12V set from the 24V circuit and use this for some lighting applications etc., within the house, but the charging of these batteries won't be so well managed as the other cells.

freddyuk

CamperMan wrote: »

I got the 24v inverter / charger cheap, it's a quality one, not like the cheap Chinese rubbish, the equivalent 12v inverter chargers would have cost me 5 times the amount.

Can you please confirm how many cheap Chinese inverters have let you down - just for the record?

CamperMan

freddyuk wrote: »

Can you please confirm how many cheap Chinese inverters have let you down - just for the record?

I have had 2 smaller 300 watt chinese inverters fail on me when used in the car running a laptop etc.