Another question about batteries

[Rasman]

Further to my previous post, I threw this diagram in (that I knocked up with MS paint that afternoon) hoping someone would either verify or rubbish it.

http://oi55.tinypic.com/34g4oky.jpg

I'm not sure it'll give what I expect and it will be a VERY expensive mistake if It's wrong.

[seadogg]

Assuming you have a meter why not replicate this series,parallel arrangement using torch batteries to check it out. Nice and cheap if you make an error.

[Rasman]

Yeah, I read what you type Seadogg and I appreciate this is something I ought to be able to sort out without recourse for internet forums.

I was hoping someone would be able to help out though, someone might look at that and say yes or no, save me the stress of experimenting and buying superfluous test gear I'd only use once.

[Rasman]

I would have thought it was an easy question for those that know

[beso]

You have two, 12 volt, nine amphour batteries in parallel making 12 volts 18 amphours. Then you have two sets in series adding to 48 volts 18 amphours.

It is better if you can use a single string of cells with none in parallel. Any imbalance in the paralleled battery performance can lead to greater losses especially if one cell becomes weak.

It can be helpful for balance to connect the pairs at the halfway point (12 volt) if it is available.

Whatever you do don't connect any loads part way up the battery. For example extracting twelve or 24 volts for lights from part of the battery is a really bad idea. If you need lower voltages use a switch mode voltage converter.