# Batteries in parallel

Discussion in 'Power Electronics' started by pidja105, Apr 12, 2016.

1. ### pidja105

106
1
Oct 16, 2015
Hello,
If I have two batteries 1.5V and first has maximum current(NOT CAPACITY) of 1 Amp and other has maximum current of 2 Amps, If I connect them to parallel will I get maximum current of 3Amps?

2. ### Gryd3

4,098
875
Jun 25, 2014
Perhaps. I'm inclined to believe so but only to a certain extent. You may end up causing damage to the 1Amp capable cell.
When in parallel, the voltage across the batteries will be the same. When you pull a lot of current from a battery, it's *internal resistance* will determine how far the voltage drops while under load. It's this voltage drop characteristic that may end up causing a higher than desired current draw in the less capable battery.
If I didn't care about the batteries, I would do it... or if I was keeping current draw less than 2A .
Otherwise, find a datasheet on the discharge characteristics for the cell and see if you can match them up. If this can't be done, then use the same type of cells throughout a pack.

*Please note, the 1Amp and 2Amp capable batteries are not what they 'put out' , but simply what they are capable of handling when under load.

3. ### Colin Mitchell

1,417
312
Aug 31, 2014
Gryd3:

You forgot to mention if the cells are they same type.
One may be Leclanche and the other may be Lithium.

Arouse1973 and Gryd3 like this.
4. ### Gryd3

4,098
875
Jun 25, 2014
I forgot to state that in my example and forgot to ask. Good catch.
Parallel of different chemistries would be a bad idea without understanding their charge/discharge characteristics... and even then, I would most certainly not do it to increase current capacity, but may take advantage of it to increase total mAh of a make-shift battery pack if I were severely limited in supplies.

I would certainly never re-charge this pack once it ran low though!

5. ### cjdelphi

1,096
104
Oct 26, 2011
What are the batteries?