Can You Wire 12 v Batteries Starting in Series then go to Parallel??

I'm getting scared with these Marsian faces on top of the pumps. Just tell maybe what voltages you want in both positions. You will need a good combination switch to avoid mistakes. With those batteries you can weld already a thick piece of metal. Your circuit should have some fool proof heavy duty contactors (relays) that are mechanically securing against wrong switching. Some old forklifts used to work that way. Tell us what you want and someone will be able to help you out I guess.

http://www.pjldiesel.com.au/docs/47.pdf

you'll find also the diagram here and the hardware

Yeah. It is possible. If you connect like this you can get an output of 12V voltage and the current eq. to the sum of all the current from the separate sources. If the voltages of diffrent value then the parrellel connection is not possible.

Hi

Off course it doesn't look right

With a diagram like this you're indeed permanently grounded

First of all: How the hell are you going to recharge your batteries equally?

2) you didn't show any neutral wiring because you don't really want to tell me you connect those ends all together ?

Never mind, give us some ratings of the pumps and the batteries ,

reason for connecting this sort of way and

ratings for operation (permanent/ backup/ occasionally)

Then we can build something.

RGDS T L.

It doesn't look right because it isn't right. The current in the red wire to the front pump must be the same as the current the black wire at the bottom (linking the left and right stacks of batteries).

I assume that the pump motors all return to a common earth.

Thanks guys for the responses. I have VERY limited knowledge when it comes to this stuff so please bear with me. LOL they do look like little Martians. They are supposed to be solenoids.

I'm trying to run 36v to the rear pumps and 72v to the front pump. 3 batts in parallel for more "reserve." The pumps do have a common ground (linked to same ground point as batts, I forgot to add that) and will be occasionally used. I don't have the ratings on the pumps in front of me but are capable of 108v and over 6000a. The batts are 12v, 1260cc.

I wasn't sure if the first 3 batts in the bank are better to be in parallel then go in series. As far as charging them, that was my next question. They will not be on a "constant" charging source. They will be charged with this charger. Charging the batts one by one is not a problem but not preferable.

http://www.batteryservice.com/products_final.aspx?Manufacturer=Schumacher&ModelNumber=SE-1072

BTW the diagram (I know poor) was more of a placement diagram… It is one batt "bank" of 8 batts with 3 in parallel.

Thanks again!!!

BTW I'm a pilot, I hope I dont get permanently grounded. lol

Forget the parallel set at the top end, you must have near equal cell capacity at each junction.

Maybe it would be better to use 2 banks of four batteries, 48V and 96V this makes it easier to series and parallel them.

It makes charging them as 2 banks simple, and you say the pumps will take 108V OK.

With the high current that they take a changeover switch is going to be expensive a small switch controlling larger DC contactors should work.

Electric fork truck type contactors can handle lots of current, I have used them with quite high voltages and found that a large value capacitor across the contacts snubbed the opening arc very well.

Equalizing charges will not be a problem since they work either series or parallel and so will drain equally, except when they run in series, the coil current will be drained from the bank it is wired to. Even this minor imbalance can be removed by using a 48V coil for parallel operation and a 96V coil for the full series voltage.