battery

[abdullahseba]

why do some battery's state that you should not connect them in parallel

[Torrentula]

The batteries might not discharge all evenly/at the same rate because of the internal/ionic resistance or aren't charged all exactly to the same level when you buy them, hence when you connect them up in parallel you one battery will 'attempt' to charge the other battery if it's not at the same cell voltage.

So the non rechargeable primary cells tell you not to connect them in parallel.

Dave did a video on battery ionic resistance:

[abdullahseba]

The batteries might not discharge all evenly/at the same rate because of the internal/ionic resistance or aren't charged all exactly to the same level when you buy them, hence when you connect them up in parallel you one battery will 'attempt' to charge the other battery if it's not at the same cell voltage.

So the non rechargeable primary cells tell you not to connect them in parallel.

Dave did a video on battery ionic resistance:

it was a rechargeable form the rs catalogue

[IanB]

NiMH rechargeable batteries should not be connected in parallel for charging if using a fast/smart charger. Parallel NiMH cells are not self balancing and there will be a tendency for one battery to take more current than the other. The result at best will be uneven charging, at worst battery damage.