LFP Cell or BMS Failure

[CharlieJ]

Does anyone have knowledge, with citation, of LFP cell failure or BMS failure in a marine house bank or propulsion bank application?

[CharlieJ]

Anybody?

[neelie]

Seems like they're more robust than a lot of people give them credit for.

[T1 Terry]

One BMS failure I can think of in a marine house battery bank, one that failed to protect the cells adequately but the cells may have survived, no actual cell failures in any house battery application, but a few tortured to death. BMS failures in EV's, heaps and heaps.
Here is one event http://www.cruisersforum.com/forums/...es-105071.html, the other was on Ebaugh's system causing an imbalance in the bank. If the bank had been smaller it could have created quite a problem and possible cell damage. This is what causes most of the problems with EV's, they have very small capacity cells, just lots of them in series, they rely on high voltage, a house system relys on high capacity and low voltage.

T1 Terry

[CharlieJ]

Its been a couple of months since I last refreshed this query. The question still stands.

[T1 Terry]

I think the problem with reporting BMS failures may result from the battery owner not understanding how it all works in the first place, something seems wrong, so they go back to the installer. If ot was a BMS mini board failure the installer/BMS system builder is not likely to say "our product failed" but rather replace the faulty item and send the system back out to the owner and give them some gobbledegook explanation that goes in one ear and out the other of the non understanding owner, ‘no idea what you just said except for "fix" so if it is I'm happy’. The result is virtually zero reporting of BMS failures.
If the system owner is also the system builder he understands a lot more about it or asks question as to why something happened, as in Ebaugh's case, he tested and discovered the failed board himself and replaced it, then there was a report of it. Others who fully understand before they even start to build their system move away from the automatic self balancing BMS system to a monitoring and alarm or switching BMS system, no mini boards to fail, so the system relies on either the owner hearing the alarm and reacting in the required way or the auto switching turning off what ever was required. If this system has ever failed would be very interesting statistics, then why it failed so that part of the system could be improved, but I haven't heard of an automated switch only system failing in any house system yet, not just in a marine house or propulsion system.
As for cell failures, only failures of one of the above systems resulting in the final death of a cell seems to be the only records any where so far.

T1 Terry

[CharlieJ]

Time to refresh this question to see if anything pops up.

[senormechanico]

Charlie,

Are you a Lead Acid dealer?
Just asking.

[Maine Sail]

Charlie,

I know Chris Witzgall (sp?) damaged some cells by not turning off temp compensation (with solar IIRC) and the temps dropped. When the temps dropped the voltage compensated up and bulged a cell or two.. While not a BMS or cell failure it is a mishap that was over looked.

Not heard of any damaged cells in house banks on boats that were caused by a BMS..

[CharlieJ]

Senormechanico=

Are you a Lead Acid dealer?
Just asking.

I am a dealer for Northstar TPPL AGMs. That said, I am on my fourth design (three designed and two installed with very satisfied clients) of LFP house banks and currently have 164 100Ahr cells in my shop for installation in project #3.

I keep refreshing this question because there is a lot of BS and innuendo down in the noise about LFP/BMS failures. I am trying to identify any failures so the root cause of the failure can be determined and the state of the art is advanced, not retarded.

Thanks RC. Points out, once again, that temperature compensation on a charging source of any type must be disabled when charging LFPs.

[Colin A]

The only failure I know of was on Mala Conducta a custom built cat. The report I received was that the boat had a direct lighting strike which took out most of it's electronics etc. When the DC system was recommissioned a fire stated in the compartment with the batteries (one of the techs on the boat at the time talking to someone here at work stated the explosion when the fire started nearly knocked him out) . There is speculation whether it was an internal fault on the batteries or some of the attached equipment that was damaged that caused the issue. I'm not sure if the exact cause was ever found.

The damage was also discussed on this forum
Lithium - the future [Archive] - Multihulls4us Forums

[hellosailor]

Considering that a lightning strike can cause all sorts of collateral damage (surge, flashover, inductive voltages and heat) that will not necessarily be visible to the eye, and that lithium batteries rely on the integrity of very thin plastic internal membranes that are easily heat damaged...Perhaps it might be considered prudent to condemn and replace any that were at all involved in a lightning strike. After all, there is literally no way to inspect them.

[Singleprop]

Here is a boat that had a near strike or possible a direct hit based on the reported damage.

The Lithium bank survived, but the leads were dead:

Lightning Reflection | Tahina Expedition

[Wraith_Mac]

CharlieJ,
You might want to contact this unhappy fellow,
Natural High Adventures - Warren's Blog
The constant overheating of his cells stands out, maybe he or his BMS was temp compensating when it's not needed?
He blames his BMS failure, and chucked out his cells and the BMS, maybe he could have just ditched the BMS.
He also confuses/conflates LiFePo4 Batteries with LiCo on a B787, so obviously doesn't know much about them or the technology.
Cheers,
Mac

[witzgall]

Spelled perfectly. The below is true, but the chargins source was the alternator. An additional issue was that one of the battery cables had a loose lug. It was between two groups of cells, and one of those groups was the two that bulged.
Chris

Originally Posted by Maine Sail

Charlie,

I know Chris Witzgall (sp?) damaged some cells by not turning off temp compensation (with solar IIRC) and the temps dropped. When the temps dropped the voltage compensated up and bulged a cell or two.. While not a BMS or cell failure it is a mishap that was over looked.

Not heard of any damaged cells in house banks on boats that were caused by a BMS..