Is this parallel battery wired wrong

[orridge]

I have been changing out our solar pvm for a mppt charger and may move to lithium so I measured the battery space and am I correct the extra battery is not correctly wired in parallel ?.

I thought you connected the positive on the first battery (to motorhome) to positive of second battery but the negative terminal on the second battery has the connection back to the system not the negative of the first battery.

Would I only be getting use out of the first battery and not the second which might explain some of the issues with low battery off grid after one or two days.

 

[Bessy765]

It would be better to put the negative to one battery and the positive to the other to provide a more equal charge.

 

[Lenny HB]

Doesn't matter when it's only two batteries close to each other.

 

[David and Sally]

I think one of the take off wires should come off the other end of the battery.
You have them both from the same battery

 

[10tenmen]

Have a look at the picture yours is wrong in that the positive should be on the other battery.
This will ensure even charge and discharge

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[Nigel Crompton]

You have the van connections made to one battery; that battery will bear the brunt of the load and prevent the second battery charging properly. It would be better for the connections to the van to be to different batteries. Doesn't matter so much with just two batteries but if you had more that that it would certainly make a difference.

 

[Lenny HB]

I think one of the take off wires should come off the other end of the battery.
You have them both from the same battery

Have a look at the picture yours is wrong in that the positive should be on the other battery.
This will ensure even charge and discharge

You have the van connections made to one battery; that battery will bear the brunt of the load and prevent the second battery charging properly. It would be better for the connections to the van to be to different batteries. Doesn't matter so much with just two batteries but if you had more that that it would certainly make a difference.

It doesn't matter when its only two batteries next to each other.

 

[orridge]

You have the van connections made to one battery; that battery will bear the brunt of the load and prevent the second battery charging properly. It would be better for the connections to the van to be to different batteries. Doesn't matter so much with just two batteries but if you had more that that it would certainly make a difference.

It's how it came as its second hand and now starting to make some changes so I thought it should not be just to the one battery for both van connections.

 

[Pausim]

The cables linking the batteries look far more substantial than the motorhome supply cables, I would be surprised if there was a significant additional voltage drop between the batteries.

 

[IRHP]

The set up is fine. Whether you connected your earth to the bottom battery or 12 inches along the connecting cable to the top battery makes very little or no difference. The way they are wired it just acts as one battery.

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[steve69]

Have you made sure all the connections are clean and oxide-free?....One (or more) of those connections may be poor compared to the others.

 

[Sandancers]

How old are the batteries ? Might be near the end of their useful life.

 

[orridge]

How old are the batteries ? Might be near the end of their useful life.

Not sure I assume they are probably the originals so likely to be end of life around 6/7 years.

 

[Jimbohorlicks]

I would also wind some red pvc tape over the black wire between the two positive terminals just to make it clear that it's a positive connection.

 

[almichie]

Have a look at the picture yours is wrong in that the positive should be on the other battery.
This will ensure even charge and discharge

In the world of fluid dynamics that is called reverse return - it ensures correct and balanced flow through each machine (battery), with the first way you have to install a balancing valve to ensure flow (voltage and current) is set correctly.

Amazing how fluid and electrics are so similar

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