Two Batteries in Parallel?

[Fithawk]

Is it possible to wire two batteries in parallel? If so, how is it done? What is required? Thanks

 

[WoodlandsCamper]

This has been discussed recently. 🙂
See this thread

 

[ProfJohnL]

Is it possible to wire two batteries in parallel? If so, how is it done? What is required? Thanks

It can be done, but why would you want to? Perhaps more detail on what you are trying to achieve might help us give a more relevant answer.

 

[Fithawk]

I'm weighing up extra battery v solar. If I go battery, I don't really want the hassle of changing a battery in the middle of the night etc. I would rather have some sort of ability to switch between battery's.

 

[ProfJohnL]

I'm not trying to be awkward, but what makes you think you will need more battery capacity, How long do you intend to be off grid, and what 12V items do you want to use? There may be other strategies that would just as effective without the weight and associated equipment of two batteries.

 

[bertieboy1]

Yes two,batteries can be connected in parallel to double the Ah capacity (provided both batteries have the same Ah rated capacity and the same voltage).
But from your operational description it seems you want to use one battery to supply the load then the second battery after the first battery has depleted.
With parallel connected batteries you will be using both batteries simultaneously.
But beware if the two batteries are at different states of charge then the battery with the higher Ah state of charge will discharge into the battery with the lower Ah capacity until they equalise in capacity.
eg 2 batteries rated at 100Ah connected in parallel.
One battery at 60% of rated capacity and one battery at 20% of rated capacity - 60% + 20%/2 = 40%
So your two batteries connected in parallel will provide 40Ah only.

 

[bertieboy1]

Re my previous reply,I should have also said that to connect batteries in parallel you connect +ve to +ve and -ve to -ve then take off the load from one of the batteries.