Lithium mini batteries

[SV Confianza]

Originally Posted by CaptainRivet

Problem with this small batteries and its even cheaper and basic BMS is that non of them alone can support any of the critical loads as backup to starter. It will die instantly if you try to start the engine with it or bring up the anchor...neither the BMS nor the pooch cells are capable of that.
The current especially surge and peaks are not distributed evenly between the batteries and the first in row will get much more wear then the other throwing that 6 parallel more off with every cycle.
Ok if you have a very small vessel with a 6" chain and a 10hp thats acceptable but eveything else you gotbthe wrong ones. Get 3 of the 200A with 1p4S and a 200A BMS or better 2x300AH if the have instead 6x100A as each single battery is capable of driving the critical loads on your boat.

The theory that all parallel are equal and equally discharged/charged is a theory, real world looks different.
These 100AH are good for cheap,lightweight and small service on an RV as a lot have a load capacity problem to drive smaller inverters and energy needed of a smaller RV. Wrong for any bluewater vessel, a small daysailor ok.

Well a 304AH battery with EVE from sunfunkits with 304AH cells is cheaper, smaller, weight less and much better quality then 3x100AH of these.
You could take 1 of these 304AH ones and add the 100AH additionally to capacity you want if you really want or eg due to insurance need drop ins. But i would simply take 2 of these EVE/sunfunkits then 6x100AH li-time

I am running our lewmar v5 windlass off these things about 10x per week for 4 months now.

Don’t get me wrong I’m not saying that someone should string all these cheap batteries in parallel like I have. I’m just testing it to see how it performs over a year. I’m going to do a capacity test after a year and see how they have aged and if they have any other problems. We use about 600-700Ah per day out of the 1000ah bank, and generally recharge to full with solar.

If they have come down in price enough to just be replaceable, and proper fusing can protect the boat, it really doesn’t make much sense to buy more expensive batteries. Just keep a spare or two… But too early to draw any conclusions.

[slippy]

My AmpereTime battery in my RV has been great (200ah 12v). These are skimpy as far as BMS, and don't do temp cutoff (unless you pay for it), but are made with new cells (unlike some cheaper LPFs).

If you ever watch an uncasing video, you'll see that these LPF batteries have a TON of airspace inside, with foam cushioning. I don't think it's required, and I think they simply want the battery to appear "big and robust". I keep waiting for someone to market the smaller size.

[CaptainRivet]

Originally Posted by slippy

My AmpereTime battery in my RV has been great (200ah 12v). These are skimpy as far as BMS, and don't do temp cutoff (unless you pay for it), but are made with new cells (unlike some cheaper LPFs).

If you ever watch an uncasing video, you'll see that these LPF batteries have a TON of airspace inside, with foam cushioning. I don't think it's required, and I think they simply want the battery to appear "big and robust". I keep waiting for someone to market the smaller size.

They use standard size casing from lead batteries in the budget price class. The 200A li time if made out of 200AH cells are a good value for money.
Stay away from the ones that are made of parallel cells inside as they will drift apart over time, in this price class its impossible they are metricously matched cells who will keep this over a long part of the lifespan and its impossible for the BMS to detect that and balance.

[CaptainRivet]

Originally Posted by SV Confianza

I am running our lewmar v5 windlass off these things about 10x per week for 4 months now.

Don’t get me wrong I’m not saying that someone should string all these cheap batteries in parallel like I have. I’m just testing it to see how it performs over a year. I’m going to do a capacity test after a year and see how they have aged and if they have any other problems. We use about 600-700Ah per day out of the 1000ah bank, and generally recharge to full with solar.

If they have come down in price enough to just be replaceable, and proper fusing can protect the boat, it really doesn’t make much sense to buy more expensive batteries. Just keep a spare or two… But too early to draw any conclusions.

Thats a great approach.
How many watts does it have 700 or 1000W?
Normal opperation of rhe windlass 6 in parallel yes but was the anchor stuck during one of these pulls?
My 1000W showes also draw of around 100A but i saw 300A on the BMS stats and surge was for sure double when my anchor was stuck underneath a rock.
yes 6 in parallel will handle that, its a question of as i described of the mosfets of the BMS.

[rabbi]

I watched four teardown videos of what should have been identical 100Ah LiTime batteries.
Not two of them were truly identical. Different cell orientation, busbar were either screw or welded, only one had a separator between cell bodies. The BMS has a 3.75v charge cutoff which IMO is far too high.


What I don't like about LiTime (and most other drop-ins that I watched teardown videos of):
None of these uses truly flexible busbars but at the same time cells are not properly clamped. So the cells will swell significantly over time and the busbars won't allow the poles to adjust.
Eve LF280K product spec is the only credible source I found for swelling & pole forces: swelling force 40.000-50.000N and max tolerable force on the poles 700N.

The German akkudoktor.net forum recently had a case where a cell caught fire when the owner adjusted clamping force without removing the busbars first.



Not what I want on my boat.

[s/v Jedi]

Originally Posted by rabbi

I watched four teardown videos of what should have been identical 100Ah LiTime batteries.
Not two of them were truly identical. Different cell orientation, busbar were either screw or welded, only one had a separator between cell bodies. The BMS has a 3.75v charge cutoff which IMO is far too high.


What I don't like about LiTime (and most other drop-ins that I watched teardown videos of):
None of these uses truly flexible busbars but at the same time cells are not properly clamped. So the cells will swell significantly over time and the busbars won't allow the poles to adjust.
Eve LF280K product spec is the only credible source I found for swelling & pole forces: swelling force 40.000-50.000N and max tolerable force on the poles 700N.

The German akkudoktor.net forum recently had a case where a cell caught fire when the owner adjusted clamping force without removing the busbars first.

Not what I want on my boat.

BS. Show the video. The person could have caused an electrical fire by shorting or by high resistance at contact surfaces, but the cell didn’t combust unless it wasn’t LFP.

[carstenb]

Originally Posted by CaptainRivet

Problem with this small batteries and its even cheaper and basic BMS is that non of them alone can support any of the critical loads as backup to starter. It will die instantly if you try to start the engine with it or bring up the anchor...neither the BMS nor the pooch cells are capable of that.
The current especially surge and peaks are not distributed evenly between the batteries and the first in row will get much more wear then the other throwing that 6 parallel more off with every cycle.
Ok if you have a very small vessel with a 6" chain and a 10hp thats acceptable but eveything else you gotbthe wrong ones. Get 3 of the 200A with 1p4S and a 200A BMS or better 2x300AH if the have instead 6x100A as each single battery is capable of driving the critical loads on your boat.

The theory that all parallel are equal and equally discharged/charged is a theory, real world looks different.
These 100AH are good for cheap,lightweight and small service on an RV as a lot have a load capacity problem to drive smaller inverters and energy needed of a smaller RV. Wrong for any bluewater vessel, a small daysailor ok.

Well a 304AH battery with EVE from sunfunkits with 304AH cells is cheaper, smaller, weight less and much better quality then 3x100AH of these.
You could take 1 of these 304AH ones and add the 100AH additionally to capacity you want if you really want or eg due to insurance need drop ins. But i would simply take 2 of these EVE/sunfunkits then 6x100AH li-time

Not sure how your boat is set up, but on ours we can't run the anchor winch unless the engine is running so there is no real strain on the batteries. We do have a bow thruster, but use it so rarely that I simply can't see that this should be a problem.

Again - LiTime warranties the batteries for 4000 cycles so that is over 10 years. More than enough for us

[rabbi]

Originally Posted by s/v Jedi

BS. Show the video. The person could have caused an electrical fire by shorting or by high resistance at contact surfaces, but the cell didn’t combust unless it wasn’t LFP.

BS? Nope

No video but a first hand story of a fellow cruiser including some pictures, followed by a discussion about the most likely cause:
https://www.akkudoktor.net/forum/akk...ne-erklaerung/

Photos are only visible for registered users so find a screenshot of the thumbnails below.


Short summary: The user used tension straps with ratchets and flexible isolation layers between cells, combined with non-flexible busbars.
He changed strap tension with the busbars firmly attached causing a battery in the middle to start boiling. While he removed the cell it started to burn violently.


Thats not the only genuine story in that forum about LFP safety issues. Want to read about a Basen Tech 48v drop-in LFP that totalled a brick house (partly collapsed after explosion). According to the owner the VRM logs show no abnormal values up to the point where communication was lost.

I am not bashing LFP (we use LFP onboard and at home) but I don't consider it 100% safe. Just like LA is not 100% safe

[rabbi]

The thumbnails I forgot to attach:

[s/v Jedi]

None of that show a cell combusting. Experiments have shown they will only combust in laboratory conditions when charged with very high voltages, i.e. more than 100V while being heated in an oven.

What I see is a burned cell. It’s easy to burn cells, just throw them in a fire.

A LFP cell is about as safe as a piece of 2x4 lumber. It will burn but not by self combustion. A little pressure is nothing compared to what they tested incl. shooting it, putting it in hydraulic presses etc.

[rabbi]

Originally Posted by s/v Jedi

None of that show a cell combusting. Experiments have shown they will only combust in laboratory conditions when charged with very high voltages, i.e. more than 100V while being heated in an oven.

What I see is a burned cell. It’s easy to burn cells, just throw them in a fire.

A LFP cell is about as safe as a piece of 2x4 lumber. It will burn but not by self combustion. A little pressure is nothing compared to what they tested incl. shooting it, putting it in hydraulic presses etc.

Its a first hand report of a cell that started to boil and then burnt down without an external short or other source of fire. You think he faked it?



My understanding is that the Lifepo4 chemistry does not allow a thermal runaway to a point where it will self ignite due to heat. But once ignited a Lifepo cell can and will burn.

Will Prose mentioned that a spark from a short is enough to ignite a punctured cell. He stresses that this isn't a true thermal runaway but merely an ordinary fire.


BTW: do you think this is fake?
https://youtu.be/07BS6QY3wI8?t=186



I think a Lifepo fire is a very rare event but not impossible.

[smac999]

It’s not that these batteries are snall for 100ah. It that’s many others are simply too big. But made same size per ah as lead for marketing reasons.

[s/v Jedi]

Originally Posted by rabbi

Its a first hand report of a cell that started to boil and then burnt down without an external short or other source of fire. You think he faked it?

My understanding is that the Lifepo4 chemistry does not allow a thermal runaway to a point where it will self ignite due to heat. But once ignited a Lifepo cell can and will burn.

Will Prose mentioned that a spark from a short is enough to ignite a punctured cell. He stresses that this isn't a true thermal runaway but merely an ordinary fire.

BTW: do you think this is fake?
https://youtu.be/07BS6QY3wI8?t=186

I think a Lifepo fire is a very rare event but not impossible.

They can burn, almost anything will burn. The video shows a cell being shorted internally by poking holes in it. The short current is very high and when more holes are poked to get oxygen in, an electrical fire starts. But that isn’t self combustion. LFP doesn’t self combust, you have to set it on fire from an external heat source, like an electrical short.

In real life, even if an internal short developed, it wouldn’t burn because of lack of oxygen.

[rabbi]

Originally Posted by s/v Jedi

They can burn, almost anything will burn. The video shows a cell being shorted internally by poking holes in it. The short current is very high and when more holes are poked to get oxygen in, an electrical fire starts. But that isn’t self combustion. LFP doesn’t self combust, you have to set it on fire from an external heat source, like an electrical short.

In real life, even if an internal short developed, it wouldn’t burn because of lack of oxygen.

Electrical shorts are not unheard of in batteries so while not exactly self-combustion the end result is the same: A burning battery.

I have no reason to believe that the cruiser with the burned cell faked the story. But with no video evidence others may choose to consider this fake or whatever.



Same for the other story I mentioned: Homeowners were alerted by an ordinary smoke detector in the basement, found one of their drop-in batteries was smoking heavily. Minutes later an explosion caused the building to partly collapse.

The owner was prettty open about the findings of insurance investigations:
One of three 48v drop-ins with pouch cells started to gas during normal operation, according to the VRM logs at around 60% SoC with charge current below 0.3c and no obvious voltage spike.
The gas exploded due to some electrical spark. They could not identify the reason why the cell started to gas.
Plenty of news coverage, forum entries, etc so I have no reason to believe this is fake.
https://youtu.be/SrLdBvcheqg?t=18



All I'm saying: While LFP has a good safety record it is not 100% safe. It is powerful and sometimes sh*t happens.

[s/v Jedi]

Originally Posted by rabbi

Electrical shorts are not unheard of in batteries so while not exactly self-combustion the end result is the same: A burning battery.

I have no reason to believe that the cruiser with the burned cell faked the story. But with no video evidence others may choose to consider this fake or whatever.



Same for the other story I mentioned: Homeowners were alerted by an ordinary smoke detector in the basement, found one of their drop-in batteries was smoking heavily. Minutes later an explosion caused the building to partly collapse.

The owner was prettty open about the findings of insurance investigations:
One of three 48v drop-ins with pouch cells started to gas during normal operation, according to the VRM logs at around 60% SoC with charge current below 0.3c and no obvious voltage spike.
The gas exploded due to some electrical spark. They could not identify the reason why the cell started to gas.
Plenty of news coverage, forum entries, etc so I have no reason to believe this is fake.
https://youtu.be/SrLdBvcheqg?t=18



All I'm saying: While LFP has a good safety record it is not 100% safe. It is powerful and sometimes sh*t happens.

You ignore the crucial details including laboratory tests and also ABYC tests showing that they will not burn under real life conditions aboard a boat. By doing that, you end normal discussion.