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

 

[Johnb]

But what does that mean ?

It means that the title of this thread is not entirely true.
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.

 

[marcham]

anytime we try to help a fellow forum member we are speculating.... if i'm not in the boat, with my eyes and test equipment, I'm making an educated guess, we all are. If educated guesses are going out of favor, then the daily post count should go down significantly : )

 

[dLj]

anytime we try to help a fellow forum member we are speculating.... if i'm not in the boat, with my eyes and test equipment, I'm making an educated guess, we all are. If educated guesses are going out of favor, then the daily post count should go down significantly : )

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

 

[geoffschultz]

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.`

 

[Davidasailor26]

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.`

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.

 

[dlochner]

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.

 

[dLj]

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.`

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

 

[dLj]

I suspect they’re looking for a reason to not honor the warranty more than a technical issue. Some lithium BMS’s can’t provide the high currents that a windlass requires, but with the proper BMS the electrons that come from a lithium battery should be indistinguishable from those that come from lead. What brand of lithium did you have?

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

 

[colemj]

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

 

[marcham]

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.`

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 ?

 

[geoffschultz]

Here's the latest response from Lofrans. Please note, I'm trying to be as level headed as possible, despite their responses:

Please mind that the windlass is equipped with a brushed S2 motor, which is designed to operate at 22 - 24V (max).

This operation point (22 - 24V) was set due to the expected voltage drop of the lead acid batteries, this operation point is common for all windlass manufacturers in the market.

Lithium supply does not have this voltage drop, on the contrary it provides a higher stable nominal voltage, which causes the RPM of the motor to increase proportially and so the heat accumulation leading to increased wear in the windings of the motor.

To avoid any issue with the new motor the voltage to the motor must be regulated by a DC/DC converter to the indicated 22-24V range. The BMS (battery management system) of the battery bank that supply the windlass must be able to handle the continuous discharge rate of the windlass onboard during operation. Please measure the actual amperage consumption of the windlass during operation onboard, in order to set up the BMS accordingly.

 

[dlochner]

Their explanation makes sense, I'm not so sure about their solution. It seems odd the motor has such a narrow voltage range. Checking the voltage at the motor while the motor is operating under load seems to be the right path, are you indeed operating at too high a voltage? I don't know if the DC-DC converter could handle the inrush current when the windlass is started under load.

 

[dLj]

Here's the latest response from Lofrans. Please note, I'm trying to be as level headed as possible, despite their responses:

Here's my take on the following from my less than expert opinion with these motors.

Please mind that the windlass is equipped with a brushed S2 motor, which is designed to operate at 22 - 24V (max).

That seems to be a pretty narrow voltage range.

Brushed DC motors are typically used where the supplied voltage can be changed to allow an inexpensive way to control speed.

My thought is that the published values of the winch are tied to that voltage range. Operate outside that range - the published values of the winch don't apply.

This operation point (22 - 24V) was set due to the expected voltage drop of the lead acid batteries, this operation point is common for all windlass manufacturers in the market.

If this is really the case, then that lower voltage would need to be lower. Or they could easily make a case of not honoring their warranty due to low voltage with the use of LA batteries. At least when I've put my volt meter on starter motors and watched the voltage drop, I've been quite surprised how low it goes. I wish I had actual number for you but I seem to recall something like 8 to 10 volts on a 12 V system. That would pretty much double on a 24V system so something like 16 to 20 volts at the terminals... Only dropping to 22V seems higher than realistically expected.

Now I've never measured on LFP, but I would not be surprised if that is significantly higher. As in very little voltage drop using LFP.

Lithium

supply does not have this voltage drop, on the contrary it provides a higher stable nominal voltage, which causes the RPM of the motor to increase proportially and so the heat accumulation leading to increased wear in the windings of the motor.

Higher RPMs will cause faster wear of the brushes - but in the range we are talking about, this does not seem reasonable. There will be more heat on the commutator for sure - but not so much in the windings. There are two competing things happening there - more current, more heat, but also higher RPMs which cause the cooling fan to be running faster so you get greater cooling. I don't know which one wins on this one... But I do know if you are running these motors at consistently lower RPM than designed for, you get heating problems due to the lower cooling effect from the fan....

To avoid any issue with the new motor the voltage to the motor must be regulated by a DC/DC converter to the indicated 22-24V range. The BMS (battery management system) of the battery bank that supply the windlass must be able to handle the continuous discharge rate of the windlass onboard during operation. Please measure the actual amperage consumption of the windlass during operation onboard, in order to set up the BMS accordingly.

Yeah... the BMS must be able to handle the current requirements - everyone agrees with that statement....

Now them telling you to measure the actual amperage - that's complete bull - that motor was designed to consume a specified amount of current. It has a running current and a peak current. They know both. They need to give you that information.

They need to tell you what DC/DC converter is required for their motor. That's not your responsibility.

I'm still back with @Davidasailor26 - they are simply trying to not honor their warranty.

I really want to know exactly who it is within Lofrans feeding you this "info" - Name and position in the company please.

dj

 

[colemj]

Lower voltage = higher current = more winding heat. Higher voltage = lower current = less winding heat.

The motor is specified by wattage, not voltage. I doubt it was specially wound for a very narrow range of voltage expecting lead batteries only (and what type of LA? Thin wound plate LA are going to have significantly less voltage drop in operation than deep cycle LA, and would exceed Lofrans specs).

The breaker used to protect it means that it is expected to operate at a certain current regardless of the source. Current is what causes heat - not voltage.

Lofrans is wrong on this. These are simple and very common motors OEM'd by several manufacturers. Our Lofran motor is the same one used on our previous Maxwell windlass, and many others. Any difference is only in the terminal stud placement and mounting ears.

Frankly, I'd send it back to either Lofrans or Knysna as unsuitably spec'd for the boat (I don't know who spec'd the windlass for the new build) and get a windlass from a better company that doesn't lie to you.

Mark

 

[Davidasailor26]

So what happens when someone with a 250A alternator running full out is charging the lead acid bank at 28+ volts and runs the windlass? What happens when someone specs their wiring to minimize voltage drop and uses an oversized lead acid bank with many CCA’s, maybe with starter batteries so they don’t sag as much? Did Lofrans really spec everything to not handle such ideal installations? If so, how do they not have more warranty claims; are all installations so borderline?

 

[marcham]

Here's the latest response from Lofrans. Please note, I'm trying to be as level headed as possible, despite their responses:

Please mind that the windlass is equipped with a brushed S2 motor, which is designed to operate at 22 - 24V (max).

This operation point (22 - 24V) was set due to the expected voltage drop of the lead acid batteries, this operation point is common for all windlass manufacturers in the market.

Lithium supply does not have this voltage drop, on the contrary it provides a higher stable nominal voltage, which causes the RPM of the motor to increase proportially and so the heat accumulation leading to increased wear in the windings of the motor.

To avoid any issue with the new motor the voltage to the motor must be regulated by a DC/DC converter to the indicated 22-24V range. The BMS (battery management system) of the battery bank that supply the windlass must be able to handle the continuous discharge rate of the windlass onboard during operation. Please measure the actual amperage consumption of the windlass during operation onboard, in order to set up the BMS accordingly.

I'd ask for a full refund from your dealer, as the product's specification are misrepresented in the literature.... A 28V windlass should not have a 24V motor. It will work, but it will burn out rather quickly. This should be advertised as a 20V windlass.