Originally Posted by sailorboy1
Just an info update:
I have now had my $306 100Ah LFP drop-in Power
11 months (they are cheaper now). They are still babies really for LFP batteries
and I have 4 of these for a 400ah house bank. These batteries have mostly only been charged by solar
. They of course charge via the alternator
while motoring and once in a while they get charged via battery charger
either using shore power
or my Honda
EU2200. For the most part they operate in the range of 60-100% state of charge. So far the biggest problem turned out to be the idiot that installed them (me) not tightening all the terminals.
Since it has been cloudy for 4 days it seemed a good time to test them for the first time before heading out again in couple of months. So I just let them run down a couple days and then hurried the discharge along today by turning on every DC load I could. I finally stopped after -342Ah, which works out to be 14.5% charged by the math and was 19.6% by the battery monitor
that has a PF of 1.05 programed into it. Voltage after a 10 minute wait with all DC power
off was 12.67V, which works out pretty much to be about 15% SOC on most curves.
So my cheap
batteries look good!!! they may have gone up in voltage more, but I wanted to turn the lights back on. In normal operation I never would have let my batteries get so low and the only time would be if I was gone a long time and solar
failed or it was cloudy 4 days.
And to note I made NO changes to my electrical system
at all changing from acid batteries to the LFPs. I had a "cruiser" type system already and all I did was change the various setpoints. Right now the charger
is running on an AGM
setting that will charge back o 14.1V and then float at 13.4V. That probably wouldn't be 100%, but who cares and I probably will turn it off once batteries are back in the 90% range.
Now I will say this, the same great things could have been written about my last set of FireFly carbon foam acid batteries at this time of use. Those lasted 2.5 years and then died a death that exactly matched partial state of charge problems they were not suppose to have.
Thanks for the real world info
I see your located in warm waters but for us in northern regions we have other issues with LFP or Li-ION batteries at low temp and BMS systems
I did not see if your LFP batteries had a low temperature switch off EG if the temperature drops below 0C degrees (32F) the switch will cut off any charger power to enter as charging
below 0C (32F ) will severely risk to damage the LFP battery .
There does it seems fo much more costly price
exist some class of LFP or Li -Ion from memory that can be charged down to minus -20 C
Most LFP batteries can discharge eg be used down to minus 20C
It is possible to buy a a solution for to cut off charger power if the temperature is too low but adds to complexity and costs .
Those prices are very good based on price
to buy LFP type cells separately make your own battery packs and buy BMS
However here for us mere mortals in this communist controlled EU we pay severe tax costs for these LFP imports
system seems to look good lots of chargers advise charge up to 95% option rather than 100% on a LFP and Li_ion charger to increase cycle life of LFP batteries and reduces risks of fire risks especially it seems for Li-Ion types us sailors rarely use except for electric
scooter or EV bikes or for some EV cars like Tesla .
For others who have deep pockets there exist 30,000 cycle
(Yes you die first the battery goes to grand children
) titanium type Lithium
batteries which can be charged at temperatures down to -20C but are not 3.7 volt cells they are 2.5 volt which means extra cells are needed
I came across a system where Lead acid battery combined with LFP can work
together in the power bank . Haven't got the info in front for me so working from memory so excuse me if I got the principle wrong
The advantage it seems is a standard 12 volt alternator
for Lead acid systems can charge the LFP through a bak of Lead acid so it claims
The alternator kits 12volt or 24 volt to convert alternators for marine
inboard engines to charge LFP are costly it seems
The logic if I recall
is the Lead acid will be charged up to higher voltages and LFP will kick in to take the load when voltage of Lead accidents drops to near dead at something like 12 volts thereby saving the necessity to have for example a costly high capacity LFP system but it probably needs a spark guy that really knows his numbers to get that solution to work
Interesting your problems with lead Foam battery short cycle life span
For now I will stay with Lead and candles to reduce the need to have batteries and buy LFP when I Finally go blue water
next year had too many expensive but not too serious health
problems last few years to be able to get away .
I have still to figure a good solution where I can throw the LFP over the side of the boat
rapidly if LFP battery or batteries ever ignites as when they ignite they are very large fires with a near impossible to stop fire until they burn themselves out something to do with Oxogen is part of the chemicals inside them and water
and foams won't stop the fire if it ever starts .
If I travel with fold up li_ ION battery stand up scooter I shall remove packs to easy able to eject over the side as those batteries are more prone to catch fire and often contain Cobalt a very toxic metal to breath in similar to mercury
metal which give a bad impact for long term life invalidity problems .
I can't wait for the Sulfer version lithium
battery to come as its seems to be a lot safer from fire risks if the Blurb is true juries out on that Unobtanuim version Battery
Is your LFP battery bank charged from Engine
or solar or wind
or some combination of these and what charger do you use to control batter charge discharge solution probably require a separate thread for that issue if you haven't got that thread already