"Cheap" LiFePO4 drop-in update

[bouncycastle]

Originally Posted by sailorboy1

Just an info update:

I have now had my $306 100Ah LFP drop-in Power Queen batteries 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

Your charging 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

[Pete7]

Originally Posted by bouncycastle

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

Close, but its the other way around. The lead-acid (LA) just sits there twiddling its thumbs. The LifePO4 (LFP) does all the work unless you use it all or the BMS disconnects for some reason. Only then will LA really do much and keep the lights on as you enter a strange harbour at night. WE also have another use for the LA. When not on board the LFP is isolated but the LA still live so the bilge pumps will run, LA being charged with solar to 100% plus float each day. After our 3rd season it works well. However, it relies on the LA being a good quality and good condition battery. You cannot expect LFP to work with a knackered LA and restore the boats domestic bank.

We are at a similar latitude and don't worry about charging during the winter, though we stay in the water. Charging temperature is also controlled by the Solar MPPT and the DC>DC charger.

There are 3 main ways to control alternator charging with an ordinary manufacturers alternator.

1. Long 25mm cable between alternator and LFP.

2. DC>DC charger.

3. External alternator regulator.

1 being the cheapest and 3 the most expensive.

Interesting to see Will Prowse on YT recently torture a cheap LFP battery by leaving it in full sun and under charge for 2 years. Think he is in LA so lots of heat every day. He tested the capacity and it was still 100%. He put it back and plans to check again in another 2 years. Therefore will believes that the idea of charging to 100% frequently reduces the capacity may not be true, but come from charging other lithium chemistries not applicable to most boats. Thought this interesting but its only one bloke with one battery.

Pete

[sailorboy1]

Originally Posted by Pete7

Interesting to see Will Prowse on YT recently torture a cheap LFP battery by leaving it in full sun and under charge for 2 years. Think he is in LA so lots of heat every day. He tested the capacity and it was still 100%. He put it back and plans to check again in another 2 years. Therefore will believes that the idea of charging to 100% frequently reduces the capacity may not be true, but come from charging other lithium chemistries not applicable to most boats. Thought this interesting but its only one bloke with one battery.

Pete

I have put the challenge out there for someone to post a link to a real test of whether leaving a LFP at 100% really reduces the capacity. Not a statement but a real science type test and so far no one has. People post post things they "think" are tests, but which are just repeated statements.

So answers from a few posts ago
1 - Alternator I have a Balmar 100 amp alternator with a ARS-5 regulator set to a B-4 belt load to reduce capacity, 90C temp setpoint, 14.1 absorption and 13.4 float

2 - Low temp protection. My LFP don't have that and I an not concerned. But there are now sub $300 100ah drop in with BMS, low temp , and bluetooth

This lithium thing turned out to be be easy once you stop reading the science project installation posts

[donradcliffe]

If your boat came with a Beneteau stock charging setup, the wire size between the alternator and the battery is probably small enough to limit the maximum charging current below alternator burnout levels. Before you spend a lot of money, put the LFP batteries in, and check the alternator output. The worst case would be to run the boat and the batteries until they are down to 20% SOC before starting the engine.

The LiTime folks are switching to BMS with low temperature protection, and are selling their old stock of batteries at significant discounts. A bargain for those who don't live in cold climates.

[shimari]

Originally Posted by sailorboy1

2 - Low temp protection. My LFP don't have that and I an not concerned. But there are now sub $300 100ah drop in with BMS, low temp , and bluetooth

The Mastervolt lithiums have an integrated heat pad that uses the charger to heat the battery while charging:

"integrated thermal heat-pad and sophisticated low-temperature control to ensure maximum charging performance at freezing temperatures. In cold weathers it uses the connected charger to power the heat-pad and keep the battery cell temperatures above freezing point. This assures the fastest possible charging and full power capabilities even on the coldest days."

The batteries certainly aren't cheap by any standard. A new 24/6000 (230Ah) runs about $12K USD believe. For some, it will be worth it. For others, it won't be. No need to judge either selection - we all pick what is best for us.

Sailorboy1 is also correct about the standards bodies meaning of "should". A control is only mandatory when "must" is used. "Should" means it is highly encouraged, but is not mandatory.

[rslifkin]

One of the big things I wonder about the LFP batteries with integrated heating is what happens in a winter storage scenario. Boat is sitting without input power, minimal power draw, etc. Batteries are below freezing, and now you connect a charging source.

How do the batteries accept power from the charger to run the heater but not actually allow the batteries to charge until they're warm enough? Do those BMSes account for that properly, or do they assume that you'll be charging frequently enough that the heaters can just keep the batteries from dropping below freezing?

[shimari]

Originally Posted by rslifkin

One of the big things I wonder about the LFP batteries with integrated heating is what happens in a winter storage scenario. Boat is sitting without input power, minimal power draw, etc. Batteries are below freezing, and now you connect a charging source.

How do the batteries accept power from the charger to run the heater but not actually allow the batteries to charge until they're warm enough? Do those BMSes account for that properly, or do they assume that you'll be charging frequently enough that the heaters can just keep the batteries from dropping below freezing?

Good question, and it illustrates (as do other questions in this thread) how much is still not known about long term use of these batteries.

[wholybee]

Originally Posted by rslifkin

One of the big things I wonder about the LFP batteries with integrated heating is what happens in a winter storage scenario. Boat is sitting without input power, minimal power draw, etc. Batteries are below freezing, and now you connect a charging source.

How do the batteries accept power from the charger to run the heater but not actually allow the batteries to charge until they're warm enough? Do those BMSes account for that properly, or do they assume that you'll be charging frequently enough that the heaters can just keep the batteries from dropping below freezing?

Yes, that has all been thought of. Charing current will run the heater, and the BMS will prevent the battery from charging until the battery comes to temperature. Will Prowse has tested this on several batteries. On the cheap batteries has found issues like temp probes missing or non-functional. But where the battery is of decent enough quality that it works at all, the heater heats the battery before the BMS allows charging.

[newhaul]

Originally Posted by rslifkin

One of the big things I wonder about the LFP batteries with integrated heating is what happens in a winter storage scenario. Boat is sitting without input power, minimal power draw, etc. Batteries are below freezing, and now you connect a charging source.

How do the batteries accept power from the charger to run the heater but not actually allow the batteries to charge until they're warm enough? Do those BMSes account for that properly, or do they assume that you'll be charging frequently enough that the heaters can just keep the batteries from dropping below freezing?

Simple most of the Drop in batteries BMSs have low temperature charging cut out. ( check the literature) . Shouldn't cost much to add 9ne. But for us liveaboards low temp is not an issue at all.

[rslifkin]

Originally Posted by wholybee

Yes, that has all been thought of. Charing current will run the heater, and the BMS will prevent the battery from charging until the battery comes to temperature. Will Prowse has tested this on several batteries. On the cheap batteries has found issues like temp probes missing or non-functional. But where the battery is of decent enough quality that it works at all, the heater heats the battery before the BMS allows charging.

That's good to know. I hadn't seen the testing of that feature.

[sailorboy1]

How many of you northern people go to work on your boats while it below freezing inside the boat? I know I never did as the snow kept me from even getting on the boat.

Just wondering. To me it is Freezing if it is less than 60F outside.

[rslifkin]

Originally Posted by sailorboy1

How many of you northern people go to work on your boats while it below freezing inside the boat? I know I never did as the snow kept me from even getting on the boat.

Just wondering. To me it is Freezing if it is less than 60F outside.

I do on a frequent basis. Working on the boat as much as I can over the winter minimizes the amount of intrusive work I have to do during the summer, plus it means I have less to do as the weather warms up in the spring and we can launch earlier (as I only have to do things like bottom paint that are temperature sensitive and where I can't just heat things up enough to work on it).

We have been storing inside (unheated) for the last few years though, which makes winter work easier. Plus the boat is less than 10 minutes from home, so it's easy to just stop by for an hour or 2 of work at a time in the winter (when it's really cold I have no desire to sit there working until I'm frozen solid).

Generally I keep the boat unplugged in the winter and there's no sun for the solar panels inside. Only things drawing power while I'm not there are the tiny draws for the smartshunt and stereo memory. When I get to the boat to work on it, I plug it in, power it up electrically and turn on some heaters. I'm generally there at least once a week to do something from the to-do list.

[Boatguy30]

Thanks for the post. Maybe replacing batteries in a friend's RV soon and will have a look at these.

[sailorboy1]

Originally Posted by Pete7

Perhaps have a read of what I said which I think you will find answers your question.

I read it. He says this whole don't leave at 100% everyone parrots may be BS

[4arch]

Everyone parrots the absolutely no charging below freezing thing and it’s not exactly true either. LFP cell manufacturer spec sheets typically allow charging down to -10 or -15 deg C at decreasing C rates as the temperature drops.

Many buyers of batteries with low temp cutoff and/or internal heating don’t really need either feature. For the majority who don’t use their boats when it’s below freezing it’s quite easy to disconnect the batteries from a charging source as part of winterization. Even if this gets neglected, outside of someone with a bilge pump that runs way too often, it’s hard to think of many winter layup scenarios where batteries would get discharged deeply enough to trigger charging above the recommended C rates.