Lifeline AGM bank of four w/ 2 older than the new ones

Do
Not
Recharge
AGM
Batteries
With
Less
Than
20% amp hour capacity recharge amperage

If the battery has been discharged more than 60% remaining capacity.

i.e. 200 ampere hours bank capacity. Equals 40 ampere MINIMUM recharge rate.

There is a time constant which seems to kick off after say 10 days of sub minimum recharge. Weekend warriors need not worry. Long-term off-grid, worry.

How many total amps will you have? Will you have enough solar?
Typical 4x6 volt = 400+ amps
1 watt per amp rule of thumb.

Good suggestions guys. I can always count on great feedback from you all

Why not prove it to yourself? Charge fully then disconnect all 4. The following morning take voltage readings across each battery. What do you see ? :)

I agree. If you still have some concerns, I'd give Lifeline a call and talk to one of their technical experts. I had an issue with a bank of 6 new lifelines and after talking to one of their engineers, I got a ton of great information on my issue and the problem I had been having as well as getting my problem solved. If you talk to them, ask them how to set up your battery bank mix. Do you put the 2 new in series together, or do you split the bank with a new and old each in their own series. I don't know if it would make a difference, but it's worth the question to an expert.

time2roll wrote:
14 months and well cared for? I would combine with the new and not worry one bit.

x2

Lifelines are very good quality, and at 14 months I think you'll be fine. Make sure all 4 are FULLY charged before connecting up. You should also monitor individual voltages to ensure things are staying in balance. Both sitting and under load.

I just yanked a set 8 4-yo 12 volters from my coach, and they're all sitting at around 12.8 with very little variation.

14 months and well cared for? I would combine with the new and not worry one bit.