Anything new in batteries for solar

OldSmokey wrote:

BFL13 wrote:

N8GS wrote:

OldSmokey wrote:

N8GS wrote:
Just got more info from Battle Born. There batteries are designed for and the BMS permits charging down to 25 deg F. Below that they will not charge but can be discharged without damage.
Saw an post today on Facebook for a Chinese 12 volt, 300 Ah LiFePO4 battery in 8D size for about $1300. The prices are coming down. I have no idea what the quality of that battery might be.
I like my Battle Born batteries, no more issues with low voltage going to the inverter.

nothing really new for the solar market.. the FLA is still the best bang for your buck..

oh, and low voltage issues are mainly due to incorrect battery sizing..:B

That wasn't the case for me. I had 600 Ah of Trojan batteries. Installed in Jan 2012, in Jan of this year I could not use the microwave, the voltage drop was just too great. When I got home, (we had been in Quartzsite, AZ) I found that 2 of the batteries were shot and the other 2 were not performing very well. Switching to LFP batteries has saved me 215# and when running the microwave the voltage doesn't drop below 12.6 volts even when the batteries are 80% depleted. When running the microwave the inverter is drawing 124 amps. I am disappointed in how the Trojan batteries performed, they should have lasted a lot longer than 5 years considering the care that I took to keep them happy.

As you know, it is the number of cycles, and how deep the cycles, that matters- not years of service. However, given that you know that, it is curious they failed. Anything to do with how tall they are? ISTR Mena was always on about that for making sure he got his stirred up often enough.

I am using a set of two 6v Exide 135s from 2011 in parallel with two used T-1275s in parallel, also from 2011--but they did two years in golf cars first then I got them in 2013) - with about 435 AH total at last test for that, and get about 0.6v drop when using the microwave that pulls about 120 amps on the MSW inverter.

It was more like 1.0 volt drop, but I found a loose wire connection and also fattened a wire a bit to get it down to that now 0.6. The batts are not that new at six hard working years, but so far so good.

Anyway, I am interested in what went wrong more than what was stated.
N8GS is no fool, so anything he has to say about all this is worth paying attention to.

I wonder how often the batteries were equalized ?

one of the biggest problems with off grid/RV solar is equalization.
a proper cycle will take 12 to 24 hours. no solar system can do this without generator help.

on a remote solar design many moons ago I overheard the customer complaining why they needed a generator on site, this was supposed to be a solar powered installation ! LOL

First off I want to say thank you for the complement BFL13.
During the summer we only take the FW out 3 or 4 times for a long weekend, so the batteries get a good solid recharge between uses. I usually gave then an equalization charge in the late fall before going to AZ in Janurary. We boondock for 4 to 8 weeks then hit a couple campgrounds as we do some site seeing on the way home. When we get back home I set out the panels and let the batteries recharge for a week or two then equalize them for a few hours. Hydrometer readings always looked acceptable and I like to do individual cell voltage test to look for anything out of the norm.
This spring when we got home I ordered the LFP batteries and pulled the Trojans out. Took each of the Trojans and put then on a CC/CV 30 amp power supply, 2 of them were reading 6.something and would not accept a charge at all. The other 2 took a charge but their capacity is definitely not what it should be. I figure I put about 60 to 100 partial cycles on them each year. and only 1 or 2 cycles would be to 50% the rest were only 20 to 25% DOD.
For the equalization I followed the guidelines on the Trojan web site.

With my new batteries the battery monitor controls the charging. I have the Xantrex Link lite monitor and it has a set of contacts that can be set to operate at whatever SOC I choose. These contacts control a relay that turns the charger on. I have been tinkering with this and currently have it set to start charging at 50% SOC and stop at 95% SOC or 14.4 volts which ever comes first.