Lofrans Windlasses NOT Compatible with Lithium Batteries

[Johnb]

Actually the Lofrans statement in their FAQ is

"Li-ion or LiFePO4 batteries will cause rapid deterioration of the Lofrans’ equipment (electric motor, control box, transmission, etc) if they are not specified correctly."

and there you have the rest of the story.

 

[marcham]

But what does that mean ? LOL..... that's like saying, don't use the wrong 91 octane gas or your car's engine fuel system will develop issues... What's the required specification ?

 

[dlochner]

The UP power lead is shorted to ground inside of the motor.

Were you able to physically locate the short, i.e., can you see the short? If so do you have a photo of the place it is shorting?

 

[dLj]

Ok, but the BMS shutting down won't weld the terminals together inside the OP's motor..... (their original complaint) 100 Amps is nothing for a Lifepo4. My 5 year old 100A (12V) pack can do 170A continuous... and they were cheap / mid range packs.

Without the actual parts and doing a real root cause analysis, we are all really simply speculating. Also, your statement above is a worst case scenario, not a longer term wear issue.

The analogy I would use that I think everyone understands more easily are the long term damages that occur in electrical devices due to low voltage. If you run at low voltage for a bit, nothing serious happens. But when you do this repeatedly over time then you observe damage. The same could happen with less than some specified amount of current. I don't think it requires that the BMS shuts down only that the required current draw is insufficient - repeatedly.

The real question that seems unanswered is what are the specific requirements needed for these devices to not be negatively affected. I suspect, given the limited information from Lofrans at this point, if they may only recently be becoming aware of this when their windlasses are being driven by LFP batteries.

I don't know what the output current looks like coming out of LA batteries compared to LFP batteries in these applications. I've never seen data showing it. I have a pretty good handle on voltage because I've measured it. But I certainly haven't done that for current. I suspect there could be short transient spikes that won't shut off a BMS, but would not be supported by the LFP battery which could easily be supported by a LA battery. But without data - it's just a guess ...

dj