Anything new in batteries for solar

BFL13,

What went wrong for N8GS may be that you always fully recover the battery bank after a trip. Not many folks are as dedicated to that effort as you are.

More likely vibration caused one of the trojans to fail, and the constant charging from solar can "hide" the problem until there is a large load. So the other three "good" jars fell on their swords trying to charge that one bad cell. It was not a catastrophic failure.

That happened to me with my bank of 3 twelve volts. I was at a campground and the Magnum inverter one morning was pouring 64 amps of charge into the banks. I separated them--the bank of four was still functional, but the bank of three within a few moments of being disconnected started producing H2S gas. It drove me and a guest out of the RV in about ten minutes. Fortunately there were no other campers in the sites on either side of us.

I decided that discretion was the better part of valor and called a mobile RV repair person who disconnected and took away all of the bank of three.

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.

It also only does 50 amps maximum discharge rate. I'd need four of them in parallel to meet my power hungry needs.

Re: 400ah lithium battery

MrWizard wrote:
it has a 20amp charge current, according to the specs, and a max discharge of 50amps

Oh.. I didn't even notice that. That's terrible!! USA 12v 100ah Li's can charge at a tremendously high rate.. 80a. If you have the charger to do that.

time2roll wrote:
IMO lithium wins hands down in ALL categories except up front cash.

Still going to be lower cost in the full life cycle. Even then they can rest at any voltage so if it degrades to half capacity in 6,000 cycles (15 years?) you just add a second in parallel. They will not fight each other.

you're right about cost.. currently about 400% more expensive but
6000 cycles, hmm.. not in the commercial world.. where did you dream up that number ?

brulaz wrote:

time2roll wrote:
So get a battery warmer.

That is the solution.

As these batts are usually installed in the warmed part of an RV anyway, it shouldn't be much of an issue when boondocking and propane heat is available.

It's when travelling in sub-zero weather that had me wondering. N8GS's solution sounds right: insulated battery box with 12V heater run off the truck's alternator or something similar.

And when putting the trailer in cold storage with no heat, just isolate the batts from any charging source, or loads.

It does make things more complicated ...

I have a schematic (ladder logic) of the wiring for my batteries, Converter, battery monitor, inverter, battery heater and the dual coil latching relay that shuts everything off remotely.
I have pasted a copy of it to the bulkhead in the battery bay in case I ever need to troubleshoot something.

it has a 20amp charge current, according to the specs, and a max discharge of 50amps

that would never work for me, too limited for my max load, and too slow to recharge for generator run time

bob_nestor wrote:
Did some more poking around and found this one: 400Ah

Yes, that's good too. I'd advise caution as batteries sold in the good 'ol USA are around that price for 100ah. Looks like with alibaba you'd be dealing with Chinese firms.

Not that the batteries you buy here aren't made in China, it's that there are no local distributors should you need warranty service. Yes, that site says "2 years", but who fulfills that? How long would it take? I also can't find its weight.

bob_nestor wrote:

time2roll wrote:
So get a battery warmer.

I wonder why the LiIon companies building these batteries for uses where they could face cold temps don't do the same thing they do for military applications. There they build in warmers and the micro controller in the battery determines when to apply heat and modifies the charge rate accordingly.

Pretty sure that's how the Li batteries in cars are handled. Rather sophisticated battery temperature management in the newer ones. Heating and Cooling too.

Apparently the Nissan Leaf got bit by high temperature issues in their early models; while the Chevy Volt and Bolts have more sophisticated temperature management and haven't had any problems.

But then cars are often plugged into shorepower when not driving, so it's easier to manage temperatures.


As for long term storage under freezing (or hot) conditions (3 months, pianotuna's scenario), the darn things are so light I would just remove them from the trailer and keep them in a temperature controlled environment and on some sort of maintenance charge.

Unfortunately, some LI makers require a refresh charge to be done every three months (iirc). My brother ruined an LI by ignoring this suggestion.

That means there has to be some way to warm the batteries in storage, and then charge them up. It is all too complicated.

I do think LI is a great idea for anywhere that it stays above freezing year round.

brulaz wrote:


And when putting the trailer in cold storage with no heat, just isolate the batts from any charging source, or loads.

It does make things more complicated ...