Adding batteries to bank

[timthrifty]

I have two Discover 42-48-6650 batteries that are about 4 years old. I also have 6 EG4-LL batteries. These batteries used to be on different inverter systems (House and shop), but I've since extended the house AC circuit out to the shop and eliminated the second inverter. The problem is that I now have these two 42-48-6650 batteries, totalling 11KwH of storage, and I don't know how (Or if I even should) connect them to the EG4 bank. I guess my questions are:

1. Can I add these older batteries to my bank? If so, is there anything I should keep in mind?

2. Assuming I can connect them, the two batteries list slightly different charging parameters in their documentation. Knowing the two model numbers I have, what should I use for bulk, float, min, and max?

Thanks in advance!

 

[Supervstech]

Of you tie the different batteries to the same bank, you need to adjust the charging parameters to never exceed the lower parameters of the set...
So, one set will never reach full charge.

Generally it is a bad idea to attach different chemistry batteries to the same bank.

 

[SignatureSolarJames]

If you have 2x 18kpv you can AC balance them over ethernet and even keep the banks in separate places

 

[timthrifty]

Of you tie the different batteries to the same bank, you need to adjust the charging parameters to never exceed the lower parameters of the set...
So, one set will never reach full charge.

Generally it is a bad idea to attach different chemistry batteries to the same bank.

The batteries are the same chemistry. They're both Lifepo4s. Both batteries have a max voltage of 58.4. Doesn't that mean they top out at the same exact spot, theoretically?

If you have 2x 18kpv you can AC balance them over ethernet and even keep the banks in separate places

Sorry, not sure what you're suggesting here. I have two 6500EX inverters and 13kw of PV. The batteries are in the same place currently.

 

[BobK53]

If you have 2x 18kpv you can AC balance them over ethernet and even keep the banks in separate places

Interesting reply from Signature Solar James (SSJ). When I call SS on the phone to learn whether I could use their LiFePO4 batteries along with Discover AES 42-48-6650 LiFePO4 batteries I got a firm NO. That was in spite of the batterie’s having the same chemistry, both being 48V and now I hear that both types of batteries have the same max voltage of 58.4V. Interesting.