Hi. In general, are there any pros and cons to having 1 larger battery (say 10kw) or to having a few smaller batteries totaling the same capacity (2 x 5kw in this case)? Assuming space isn't an issue and the batteries' other specs and price per kw are the same?

Edited August 28, 20232 yr by yusuf.o

More batteries-pros

Backup in case one or more dies

Load is shared so less stress on one battery incl fewer cycles (potentially)

Upgrades are less investment as smaller capacities are cheaper

Cons

More cabling and complexity

Larger install footprint

More points of failure (could be a pro as well)

Added effort to balance (?)

 

One battery-pros

Smaller install footprint

Less cabling and associated complexity 

Cons

Single point of failure 

Greater stress on the single battery

Upgrades may be a larger investment as often you can’t mix sizes

Edited August 28, 20232 yr by mzezman

What @mzezman said. To me the main benefit is that if my single 10kWh battery gives trouble, they take the whole battery away. But if I had 2x5kWh batteries, I'd likely be left with 5kWh and would still be able to get through a load shed. But there are also the complexities he notes, and 2x5 usually costs a bit more than 1x10.

@mzezman summarized it very nicely, personally I like the idea of multiple batteries a bit more. The redundancy of extra batteries is always great and the load is split between the batteries so the cells may not be charge / discharged as quickly (ie. If your inverter can charge at 100A max, then in theory each battery would get 50A as opposed to a single larger battery getting the 100A).

 

So personal preference can come into play here, you should also consider what you might need or do in the future. If you might have a need for say 20KWH of batteries than going for a single 10KWH and adding another 10KWH later on might make more sense than ending up with 4x 5KWH batteries.

Thanks @mzezman@Bobster. @PsyCLown thought the multiple batteries would be the better option but was hoping there was something I was missing to save a bit on the setup. Hopefully taking the plunge this week, prices have come down nicely recently