This is an old thread but has had some recent posts. When we built, far remote, deep forest and off grid with ZERO services, I planned solar from the beginning. 48vdc system with 8 Trojan REb blocks. I went through 2 banks in 11 years. When the 2nd bank was at end of life I went with LifeP04 blocks, actually 3ea SimpliPhi 3.8. Within the first month I was so astounded by their performance that I thought forward and if one of them failed I would not want to get by on 2 blocks. So I bought a 4th and configured them into a 2x2 bank. This upgrade is coming up on four years.
From the beginning I sought to have as close as could be a system that would be reasonably hands off in case something happened to me and the Wife had to step into operation and maintain the system. Batteries were the main demand on maintenance. 2nd would be generator operation and maintenance during low light season (PNW). The wife has the ability to undertake specific gravity, connection service, fuel and oil, etc but she would curse my memory having to do so. Generators, sigh.
The LFP04 batteries were a major game changer. They are in the 'crouch space' instead of the outside life the Trojans. I do ZERO maintenance on the batteries except to do a balancing charge each month - or maybe every other month - or (wink). We are coming up on the 4th year of service from the LFP04 conversion. There is little no measurable difference in their performance since they were commissioned. I have done a few things to the solar over the years and nothing made the change in operation that the new batteries contributed. But the upgrade was a hit to the budget. Would I do it again? In a heartbeat.
Here are a few things:
- No real physical maintenance;
- Safer than lead. Don't fall victim of the horror stories of exploding batteries. BS. Some cheap Chinesium batteries maybe but you get what you pay.
- Capacity: the rated amp hours ARE usable. Lead batteries with the rated storage WILL be degraded if you use them more than 50%. LFP04 could give a flip. Just don't kill them dead.
- Energy savings: We run 3 months more than less on generator power. The generator has to recharge the batteries because of lack of sunlight. The LFP04 batteries charge AND discharge with very little loss in efficiency. Over the course of the winter this amounts to many gallons of fuel not burned. Think on that.
- Oversized battery bank: We have 15 kWh of storage. We use barely half of that so we have most of a 2nd day if I bonk my head and am down. Oversizing your bank means you don't have to charge them full (a wear and tear thing) and they rarely get below 50%. LFP04 has virtually no usage memory. So not charging them full and not substantially depleting them means little to no change in performance. So you stay below a full top end voltage hit and don't go too deep. They are warranted (for what that is worth) at 80% depth of discharge for 10,000 cycles. We run around 35 to 40%.
I am new here and this is about the first time I've been able to comment on something worth writing. You can McGivor whatever but if you aren't available SOMEONE has to follow up behind you. Don't put this on other people. Build, as best you can, something that is manageable, by those behind you. If you love them you won't saddle them with a complex system that no one can operate in your absence.