Lofrans Windlasses NOT Compatible with Lithium Batteries

Davidasailor26 · 2026-01-08T02:25:09-0800

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?

dlochner · 2026-01-08T04:40:39-0800

As @Davidasailor26 says, it shouldn't matter where the electrons are coming from. What would matter with LFP is the max discharge rate and max pulse (10 sec) discharge rate. Depending on how which batteries you have and how they are wired they may not be able to supply sufficient current. Some of the NG batteries have a max discharge rate as low as 100a.

Lofrans probably doesn't want to deal with the nuances of installing a LFP system suitable for use with their windlasses and has taken the tried and true route of only using LA batteries. A LA battery could be installed near the windlass and kept charged with a DC-DC charger. A group 27 or 31 AGM and a ~20a charger would work.

colemj · 2026-01-08T05:32:22-0800

We have a lofrans that has been operating on LFP for 7 years now.

rgranger · 2026-01-08T08:07:28-0800

colemj said:
We have a lofrans that has been operating on LFP for 7 years now.

How far is your run from the batteries? I wonder if @geoffschultz has a longer run?

jssailem · 2026-01-08T08:23:48-0800

The location of the notice in the FAQ section sounds like Lofrans recently discovered this issue with their Falcon windlass. Discovery of the issue without notification to the current users sounds like a negligent action on their part. Sounds like there is a problem, and we will hide it on the website.

Not a fun time to have to challenge the company. Did you install the windlass, or was it installed for you? If the latter, then you may have a claim against the business that installed the windlass.

Is there a Warranty period?

marcham · 2026-01-08T09:27:16-0800

I can't imagine that being the root cause (lifepo4 cells) as AGM can also be charged to 28.8 V..... What are the charge settings for your lithium batteries? Maybe they didn't spec a component correctly and components die prematurely with the higher under load voltage. Use a controller from a different manufacturer?

marcham · 2026-01-08T09:34:12-0800

Nothing in the spec sheet either.....

I'm super happy with the quality of my lofrans windlass, but documentation/ packaging QC is lacking. My install manual came with missing pages and the remote shipped with a European wago connector, but no instructions on how to open the clamps...(Wago makes a $0.30 tool).

dLj · 2026-01-08T10:36:05-0800

marcham said:
Nothing in the spec sheet either.....

I'm super happy with the quality of my lofrans windlass, but documentation/ packaging QC is lacking. My install manual came with missing pages and the remote shipped with a European wago connector, but no instructions on how to open the clamps...(Wago makes a $0.30 tool).

Actually look more closely in that spec sheet and read where it says working load in amps. The systems they build, as I understand it, are more sensitive to correct current loads which may not be supported by the BMS of the LFP batteries. If you do have LFP batteries with a BMS that supports the required current flow that shouldn't be a problem. But looking at the 12V requirement - that's 160 amps. A lot of BMS may not support that. Even if they don't shut down, they may throttle back to a lower current flow which appears could be the issue.

dj

yelkenli · 2026-01-08T10:52:55-0800

Does anyone pair super-capacitors with the Lithium batteries and its BMS to provide the needed in-rush and working amps?

rgranger · 2026-01-08T13:11:49-0800

yelkenli said:
Does anyone pair super-capacitors with the Lithium batteries and its BMS to provide the needed in-rush and working amps?

Creative "potential" solution...

BarryL · 2026-01-08T14:10:38-0800

Hello,

It's pretty easy to find a lithium battery that can provide 200 amps continuously. Why bother trying to design a system with super - caps when the battery manufacturer does it for you?

Wattcycle makes a small 314AH 12VDC battery for $450 or so that is small and light and provides 200AH

[Bluetooth-Free Version] Wattcycle 12V 314Ah Mini LiFePO4 Deep Cycle B

Reliable deep-cycle lithium battery with long runtime and 10-year lifespan. Perfect for RVs, solar systems, and off-grid power.

www.wattcycle.com

Note that I have never used one of those batteries but they do have good reviews.

I plan on moving to Lithium batteries next year.

Last comment: How does the windlass know what kind of battery is providing the energy? It doesn't. As long as it gets sufficient power it should work. Now if your battery can't provide sufficient power it seems to me that the windlass should stop working but it should not be damaged. But I am not an EE.

Barry

yelkenli said:
Does anyone pair super-capacitors with the Lithium batteries and its BMS to provide the needed in-rush and working amps?

dlochner · 2026-01-08T14:24:45-0800

BarryL said:
Now if your battery can't provide sufficient power it seems to me that the windlass should stop working but it should not be damaged.

The problem is resistance. It takes a lot of initial power to get the motor to spin. If there is not enough voltage and current the winding heat up and damage the windings. The unloaded the windlass may work, however as soon as a load is applied the resistance goes up and if there is not enough current and voltage the motor bogs down and the windings heat up potentially damaging them.

Davidasailor26 · 2026-01-08T16:44:45-0800

dlochner said:
The problem is resistance. It takes a lot of initial power to get the motor to spin. If there is not enough voltage and current the winding heat up and damage the windings. The unloaded the windlass may work, however as soon as a load is applied the resistance goes up and if there is not enough current and voltage the motor bogs down and the windings heat up potentially damaging them.

I agree, but with lithium I thought the failures usually happened on the BMS side, not the appliance side. My understanding was that if an appliance tries to draw more than the BMS can provide the BMS either cuts off all output or fries. Is there a failure mode where a BMS would provide an intermediate voltage that could burn the windings without running the motor?

JoeWhite · 2026-01-08T17:33:46-0800

I am EE and Barry is right. When voltage drops the current will increase, this could drive higher current in the windings. But isn't there a fuse in this line to stop the current before the motor is becomes damaged. It may not have been installed properly. The type of battery has nothing to do to cause the failure.

Jan_H · 2026-01-08T17:38:08-0800

I think the answer is along the lines of what @dlochner noted - the power drawn from the battery (voltage x current) must be transformed into mechanical power (speed x torque) and/or heat in the motor (or wiring). If the motor isn't turning, it's all heat, which quickly fries the motor windings.

marcham · 2026-01-08T17:43:34-0800

dLj said:
Actually look more closely in that spec sheet and read where it says working load in amps. The systems they build, as I understand it, are more sensitive to correct current loads which may not be supported by the BMS of the LFP batteries. If you do have LFP batteries with a BMS that supports the required current flow that shouldn't be a problem. But looking at the 12V requirement - that's 160 amps. A lot of BMS may not support that. Even if they don't shut down, they may throttle back to a lower current flow which appears could be the issue.

dj

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.

marcham · 2026-01-08T17:46:21-0800

Jan_H said:
I think the answer is along the lines of what @dlochner noted - the power drawn from the battery (voltage x current) must be transformed into mechanical power (speed x torque) and/or heat in the motor (or wiring). If the motor isn't turning, it's all heat, which quickly fries the motor windings.

If the motor stalls, the current goes through the roof. The breaker should kick in. The thermal breaker delay decreases quickly as the load goes past the rated current. I've seen windlasses on boats that are 20+ year , they stall once it a while and nothing burns down. Corrosion from leaky seals (gearbox) is what gets them in my experience, or the up/down relay box.... but the motors usually last forever...

I hope the OP can get more info from Lofrans...

marcham · 2026-01-08T17:46:50-0800

geoffschultz said:
I'm in the process of commissioning my Knysna 550 catamaran, and my 24V Lofrans Falcon 2000W windlass died after maybe 6 anchoring sessions. The UP power lead is shorted to ground inside of the motor. I contacted Lofrans support, and here's what they told me:

We would like to inform you that the unit is not compatible with lithium supply and in order to avoid rapid deterioatation of the electrical and mechanical equipment we strongly suggest to install lead acid batteries.

I've searched their product web site as well as their install manuals, and no where does it say this. I did find it in their FAQ section, but one shouldn't have to read the FAQ to determine this. It should be on every web page and in the install manual!

I can only surmise that Lofrans will be going out of the windlass business if this is true, as virtually every new boat being built utilizes lithium.

What thermal breaker was installed ? (ie: rating and model)

Lofrans Windlasses NOT Compatible with Lithium Batteries

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SBO Weather and Forecasting Forum Jim & John

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