Lofrans Windlasses NOT Compatible with Lithium Batteries
- Thread starter geoffschultz
- Start date
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 ?
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 ?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?
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
It means that the title of this thread is not entirely true.But what does that mean ?
It means that this is a problem that needs to be solved by having all the facts, and properly understanding what you are talking about.
Bit of an overstatement seems to me... There's a difference between speculation and educated guess...
There's another thread same exact subject - I'm guessing same OP - over on cruisers. There are other windlass manufacturers that also say you have to use the correct LFP set-up or they cause problems - better to use LA. Still no answer as to exactly what "correct" is...
This one just seems to be well beyond anything I've had to deal with before. And I haven't seen anyone even remotely give an explanation that makes any sense at all... Doesn't help the manufacturers are saying LFP not so good, LA good, but no explanation...
dj
Here's a reply from Lofrans that I received yesterday:
The problem of the lithium batteries is that they can supply higher voltage than the motors standard 22-24V need and up to 36-42V.
With that being said, we have many end uses in our community, who are using lithium supply to our standard windlasses by specifying the lithium battery and BMS accordingly, in order to handle the discharge rate of the windlass and regulate the voltage with the help of a DC/DC converter. This solution seems to work with some occasional hiccups from the BMS and control box.
So please contact our representative in South Africa to replace your motor but make sure you supply the requested 24V as the motor is designed for this power.`
The problem of the lithium batteries is that they can supply higher voltage than the motors standard 22-24V need and up to 36-42V.
With that being said, we have many end uses in our community, who are using lithium supply to our standard windlasses by specifying the lithium battery and BMS accordingly, in order to handle the discharge rate of the windlass and regulate the voltage with the help of a DC/DC converter. This solution seems to work with some occasional hiccups from the BMS and control box.
So please contact our representative in South Africa to replace your motor but make sure you supply the requested 24V as the motor is designed for this power.`
I don’t care for that answer very much. A lead acid bank, when being maintained by an alternator or charger, would still easily exceed 24V. And what 24V lithium bank would provide 36+ volts? Certainly a lithium bank can provide a voltages toward the higher range of what lead can, but it should just consistently remain in the upper part of that range rather than sagging the way lead does.
24v LFP is really 26.4v. Which is only a volt or so above the recommended 22-24v. It seems the motors are not as tolerant of voltage variations as we might expect. I suppose one way of dealing with this is to increase the wire length or down size the wire to drop the voltage. The current draw might be excessive to use a DC-DC converter.
I'm sure scratching my head on this one.
@geoffschultz - can you please send the actual response from Lofrans you got? Also, can you please send photos of your motor?
This makes absolutely no sense to me.
dj
At this point, I think @Davidasailor26 had the correct response from the get go....
They are looking for a reason to not honor the warranty. Nothing else makes sense.
dj
Lofrans is full of it on this. There is no lead battery that will operate the windlass between 22-24V because that battery would be almost dead and not have enough left to run the windlass.
Fully charged to the limit LFP batteries would supply 29V. A fully charged FLA battery would supply 30V. The only difference I can see between the two is that when the windlass was operating, the LFP would be at 29V, while the FLA would likely sag to 26V or so.
There is no BMS that I'm aware of that regulates voltage or current. They just shut off charging or load when programmed voltage or current limits are reached.
I suspect the OP has either a bad windlass, or a problem with the installation causing a voltage drop.
Mark
Fully charged to the limit LFP batteries would supply 29V. A fully charged FLA battery would supply 30V. The only difference I can see between the two is that when the windlass was operating, the LFP would be at 29V, while the FLA would likely sag to 26V or so.
There is no BMS that I'm aware of that regulates voltage or current. They just shut off charging or load when programmed voltage or current limits are reached.
I suspect the OP has either a bad windlass, or a problem with the installation causing a voltage drop.
Mark
Just like the FAQ, a non-answer from Lofrans.....
a nominal 24V lifepo4 bank voltage charges at 28V, a nominal 24 V AGM bank voltage charges at 28.8V-29V. Both chemistries will have voltage drop, depending on many factors (wiring size, length, battery age, etc...).Who would use a 24V windlass on a 42V system???
I suspect there's more to the OP's failure than a voltage incompatibility.
WHat is the fuse rating? What brand/model? Were the motor terminals torqued to spec ? (loose terminals will cause heat and melting, overloading the motor will cause heat and melting).
The only thing I can think of that might fuse / melt terminals on the motor is overloading and the fuse not tripping. Cheap amazon thermal breakers are known to have inconsistent trip current (lots of testing on YouTube).
Can we see photos of the failure ?