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Connecting 2v Lead Crystal Batteries Correctly

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I have purchased 24 CNFJ-1000 Lead Crystal batteries (See)

to be connected in series to give 48 volts for a 15Kw Microcare inverter. A single battery has 4 neg and 4 pos terminals. The configuration is such that it appears that internally the battery is split into two 500AH batteries. I thus get a 2V reading over the LHS two terminals or over the RHS two terminals. There is no reading over the furthest LHS to the furthest RHS terminal.

As I need 48V the batteries need to be in series. Two options exist to do this and advice or hopefully some technical information could be shared with me. Your help will be appreciated. Regards Mark you can mail me

Method One: Connect each one of the cells from one battery to the next in series for all 24 batteries and put a "bus bar" over the final row of negative and the final row of positive cells with one lead going to the positive input on the inverter and one to the negative.

Method Two: Connected the two center terminals, negative together and positive together of a single battery and then the two outer terminals negative to positive of the following battery. This would make each battery firstly connected in parallel and then in series.

I have been given many opinions by "experts", but nobody has any technical backing. I quite frankly do not have the ability to decide. Can somebody please help.

At a guess you need to bus all 4 terminals positive and negative on each cell, so that the current flow is shared between the terminals equally. Then connect the batteries all in series with jumpers.  The 2 terminals per cell is there likely to keep the current per terminal down,  The max rating of 10kA per battery indicates the terminals are rated only for 5kA each, so the internal bus bars likely are limited to that as well.

Connecting like that also reduces the risk of terminals shorting together.

Thanks so much for the response. I do not understand why all in series and the last in parallel will not serve the same function. Could you perhaps elaborate.

No real difference, just that there is more risk of you making a mistake in connecting them together. There you have to have a diagonal jumper per cell block, and there is a great risk of incidentally connecting a cell in reverse doing that.  A battery capable of 10kZ will at a minimum cause a blast of acid to vent if it is shorted, and can explode with great violence. Something best watched from afar. As well placing each block in parallel means you can easily take out individual cells to service them, and no jumper wires interfering with the filling holes.

Dear Sean,
Thanks again for your response. I have already done the connections and am running the system in a series fashion with a bus bar on the ends. The batteries feed into a 15Kw microcare inverter and works perfectly. My question arose because I was told by an installer that I should have connected each battery in parrallel before going in series. He could give no reason. Your practical point of view for maintenance purposes makes a lot sense. Thanks again. Regards Mark


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