Wiring batteries in series-parallel

[dtrask]

Hi, I'd like to increase the capacity of my current 24v system which is currently comprised of 2 12v bigbattery OWL 170ah wired in series. If I buy a 24 v battery 100ah and wire it in parallel with what's currently installed, what problems will I have (if any). If the amp hours are mismatched will this create a problem? Is there another way without scrapping the batteries I currently have?

 

[DIYrich]

What chemistry is the bigbattery? Should be ok if lifepo4.

 

[sunshine_eggo]

Hi, I'd like to increase the capacity of my current 24v system which is currently comprised of 2 12v bigbattery OWL 170ah wired in series. If I buy a 24 v battery 100ah and wire it in parallel with what's currently installed, what problems will I have (if any). If the amp hours are mismatched will this create a problem? Is there another way without scrapping the batteries I currently have?

The official answer is "same everything" but many successfully parallel different brands, ages and capacities.

Consult link #6 in my signature for best practices on paralleling batteries. Once complete, you should test that currents are within limits with a clamp DC ammeter under heavy load and charge conditions.

 

[HighDesertOffgrid]

The only issue is see is the larger 170ah bank will be moving more energy to maintain equal voltage thus will cycle out faster. Not a deal breaker in my book.

 

[dtrask]

The only issue is see is the larger 170ah bank will be moving more energy to maintain equal voltage thus will cycle out faster. Not a deal breaker in my book.

If I can afford it, would I be better to get a 200ah 24 v battery as the new one? Closer to 170?

 

[dtrask]

What chemistry is the bigbattery? Should be ok if lifepo4.

Everything is lifepoe

 

[dtrask]

The official answer is "same everything" but many successfully parallel different brands, ages and capacities.

Consult link #6 in my signature for best practices on paralleling batteries. Once complete, you should test that currents are within limits with a clamp DC ammeter under heavy load and charge conditions.

Ok...dumb question, but how do I get to your signature to see the link?

 

[timselectric]

Ok...dumb question, but how do I get to your signature to see the link?

At the bottom of every one of his posts.

 

[HighDesertOffgrid]

If I can afford it, would I be better to get a 200ah 24 v battery as the new one? Closer to 170?

Everything is relative. It also depends on the internal resistance of the cells and their sums in each bank... the age of the original bank... blah, blah, blah...
Better? Probably. Enough to be concerned about? Probably not.

 

[dtrask]

Ok...dumb question, but how do I get to your signature to see the link?

Nm...found it