Apologies for yet another noob question. Should we go single 10kw or 2 x 5kw batteries. Is there any particular item to be worried about on either setup?

2 minutes ago, Geiger said:

Apologies for yet another noob question. Should we go single 10kw or 2 x 5kw batteries. Is there any particular item to be worried about on either setup?

If i could do it again id go for a single higher capacity battery - reduces the amount of wiring and complexity in balancing (ensuring the multiple smaller ones charge and discharge relatively uniformly 

Thank you mzezman, most appreciated.

Just know that you have to phone a friend to lift a 10kWh battery.

1 hour ago, Geiger said:

Apologies for yet another noob question. Should we go single 10kw or 2 x 5kw batteries. Is there any particular item to be worried about on either setup?

Think of Redundancy, you want to have back up when your battery fails. If you go for a 10kw and the battery fail for some reason and has to be sent in for repairs or warranty swap, you are doomed. If you go for two 5kw, one fails and you still have one to fall on or use while waiting for the repairs. Also, for trouble shooting, if you have an issue and suspect the battery has a problem, you can always test by using one battery at a time to isolate the issue. If you have only one battery then you will have to pay someone to come and assist you. Two is always better than one, no matter how you look at it and do not worry about any ''complexity in balancing'' leave that to BMS. You are not planning on DIY battery, right? Also, amount of wiring is nothing to worry about as the wiring linking the batteries come included when you purchase them. I'm talking based on Pylontech, not sure about other brands 

5 minutes ago, hoohloc said:

Think of Redundancy, you want to have back up when your battery fails. If you go for a 10kw and the battery fail for some reason and has to be sent in for repairs or warranty swap, you are doomed. If you go for two 5kw, one fails and you still have one to fall on or use while waiting for the repairs. Also, for trouble shooting, if you have an issue and suspect the battery has a problem, you can always test by using one battery at a time to isolate the issue. If you have only one battery then you will have to pay someone to come and assist you. Two is always better than one, no matter how you look at it and do not worry about any ''complexity in balancing'' leave that to BMS. You are not planning on DIY battery, right? Also, amount of wiring is nothing to worry about as the wiring linking the batteries come included when you purchase them. I'm talking based on Pylontech, not sure about other brands 

Redundancy is a good point to consider. Another point i guess is that should you need to upgrade - with a 5kw you'd only need another 5kw but with a 10kw you'd need one of those - its pricier

Again, thank you all for the responses. @hoohloc, yeah, will not DIY, thanks again.

I agree with the point about redundancy. I've always had a single 10kWh battery, first Revov, now Freedom Won. There was a query about the Revov. They wanted to put it on their test bed. Not an unreasonable requirement, but it left me with no battery at all for a couple of days. This is the exact scenario that @hoohloc describes.

As regards extending the battery, you can go from two 5kWh batteries to three. You can upgrade in smaller, more affordable increments. If you go for 10kWh then you have to extend to 20.

Downside: 2x5 usually costs more than 1x10 of the same range, and you may need to buy some extra cables to interconnect the batteries. 

My system is what it is now, but if I were starting afresh, I'd give serious thought to 2x5. So well done on asking a good question. 

Dual as redundancy is the key.

Hey there have to agree that redundancy is much more important than less cables - cables can be tidied up -  as noted for redundancy, swap out or expansion, all are valuable to consider - the only time one larger battery becomes a consideration is when there is an unavoidable space consideration and one large battery is your only option, but then buy big and well known which equals very expensive - think LG Chem.

Thank you to all again. 

I have to agree on 2 smaller lithium than one bigger one .

But for me in the beginning it was more the cost I could not afford one big one and so bought a small lithium and later another one but on the long run this method is more expensive . 

But also but not the main reason having 2 smaller helps if one fails and has to be sent in there's still anothere so the system can still run .

Enjoy 

Edited June 18, 20232 yr by GMAC