HGLTECH 100Kv Test and Comparison

After a little bit of a bumpy road when first joining the efoil.builders forum and a bit of a postage issue with Felix, HGL reached out to me and asked me if I was prepared to review their one motors for them and chat about it here. They are really keen to build some trust with the efoil forum (this would obviously lead to sales for them) and improve their product offerings.
I’ll state upfront that I have no vested interest in this and don’t stand to gain anything as I can access the motor manufacture directly anyway if I want cheap motors. This is going to be a candid review of the whole process…

The motor is the one at the following link: https://www.gd-hgl.com/products/65162-100kv-120kv-motor and can currently be bought with 10% discount if you use discount code OFF10.

I requested a 100Kv motor as I already have the Maytech 120Kv which I have been using with the FR prop for over a year now. This would allow me to do a solid comparison between the 2 units and different KV ratings. I wasn’t sent a prop with the review unit, so I went out and got my own prop. I chose the 8" pitch version as I have previously run an 8" pitch 3D printed prop on the 120Kv and it handled it alright. Here is a link to the prop I chose: https://www.banggood.com/7-12x8-BA-Aluminum-Outboard-Propeller-For-Yamaha-Mariner-4-6HP-6E0-45941-01-EL-p-1334472.html?rmmds=detail-left-hotproducts__1&cur_warehouse=CN

After ordering, HGL sent the motor with Fedex and it arrived in 3 days. Here are some pics of the packaging and unboxing:

Package came taped to within an inch of its life and box was undamaged.

Once first box was open, as you can see there is loads of foam padding.

The motor box was also fully wrapped in bubble wrap

As Felix has already pointed out, it appears they have improved the padding inside the main motor box so that the motor can not longer shift and push the shaft through the box.
This packaging is a lot better than the old packaging that was used a year ago and should hopefully avoid any motor damage during shipping.

The motor has the spline shaft and the ceramic seal.

Next I will be opening the motor and adding some corrosion X so that it has extra protection should any water happen to get inside and also cutting the prop down somewhere between 140-150mm.
I have a decent size pool in my back garden so will also do some static tests which should give me a good indication of what speeds I can expect from the combination…

Update 1:
The first test for this motor was to establish the actual KV (what the motor spins at) the motor has. This was done with nothing attached and nothing added to the motor. I found that the motor spun at 95kv. This ties in pretty similarly to the 120Kv motor where i also had a loss of 5kv and had it spinning at 115kv.

I have now modified the prop to 150mm. It now looks as follows:

Next step testing in the pool…

Update 2:
I am using a 12S battery and the ARC200 ESC. No corrosion X in motor yet…

100KV motor:
Unloaded RPM is 4375
In the pool, the motor managed to get the prop speed to 1850 RPM. Plugged into the mercury prop slip calculator this would translate to a speed of 13mph (it would be higher in a non-static environment).

120KV motor:
In the pool, the motor managed to get the FR prop to 2540 RPM. Plugged into the prop slip calculator, this results in a similar speed as above. But it should be noted that the This combo had way more thrust and moved way more water in the pool.

Next up is taking the 8" pitch prop down to 130mm to see if I can get more rpm out of it. I’ll probably take the 8" pitch prop down to 120mm eventually before I introduce the FR prop to the 100Kv motor.

What sense does it make to compare a 100kv motor with a 120kv motor?
Same speed would be the first approach, use the same prop and then see what the measuring device and the board show.
Greetings Frank

To see if the minimal difference in Torque makes any difference or not in reality with a lower KV unit. I have identical FR props to test them with as well.

The motors are made by the same manufacturer, so the same KV ratings from different resellers will be near identical. Therefore there’s no reason to test identical KV motors against each other.

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I don’t know about this motor, but for mine 90kV vs 110kV was like 1Nm difference, so might not be so minimal.

The precise reason I got a different KV motor to see how it translates…


I have also 100 and 120kv available, both form Flipsky. But I had to buy both, lucky you.

Looks good, however if you should make an review of the motor, why don’t you simply leave it be and try it. I mean not everyone wants to open the motor then and fill it with corrosion x and also cutting the prop. They have shown a graph how well the motor performs, so simply test it without any Modifications and tell us how it went please.


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I have to agree with Felix on his point. HgLtech says the remote and engine together with propeller is plug and play and do not need any modifications.
It would make More sense to try their stuff as it is sold and not modify The motor with oil and open it after half year running to see how they look like inside.
I totaly understand why you not run it without oil and cuting down the propeller because we know it will not work good :slight_smile:

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It’s a 1-2 punch, right?
-17% lower current will be needed for same torque with the 100kV motor, equals 31% lower ri2 losses in esc at same torque.

But maybe more important: Max rpm will be 100/120=83%

Motor torque needed to drive a propeller is squared with rpm —> Motor torque needed at max rpm will be 31% lower for the 100kV motor as it cannot achieve same rpm. Some of this will be regained as loaded rpm drop will be less for the 100kV motor, don’t know how much.

These differencies has to be taken into account when comparing with same prop.

Question is, do hgltech claim any improvements in their motor compared to the others?

  • I know that if I just leave it and try it, it will perform just like everyone else that left it and tried it. I don’t desire to replace the bearings if water does happen to get in. There’s always a slight chance of a mild defect on any product therefore it makes sense to add a precautionary measure just in case. I bet you add a casr to your smartphone just in case you drop it…
  • The graphs they have do not show any data from the prop. That is other test data from the factory. In addition the prop I have is higher pitch than the one they sell so it needs slight modification. This then enables me to recommend better props and modifications for them to make for future products.

This has nothing to do with the remote. I have not mentioned it anywhere…

We already know what the results of this will be from countless other forum members that have bought the same motor with different branding. Adding mineral oil or corrosion X is a super simple addition to the motor and helps the longevity of the motor hugely.

Adding oil makes pretty much zero difference on performance, it just lengthens the lifespan of the motor.
Cutting down the prop is done because this prop is much higher pitch than the one offered with the motor and I am going to match it better and make recommendations off it.

No they have not claimed theirs is better than anyone else to me. They merely asked me to review it and make recommendations on how they can improve their product offerings.

This means you already recommend to them that they should add corrisionX and another prob?

That would progress the current status of the motors. A 100% matched prop and factory corrosion protection would give hgltech the upper hand for a while.

Please keep us updated how they reacted to your recommendation. Because as you wrote, at the performance part there is no difference to the other motors.

I think if they put corosion x in the motor can at manufacturing then they need to change export and import due to liquid and it adds to the price. Could be wrong here but ive had same at work with electric motors from China into EU.

Exactly this. In addition it’s such a simple mod to take on yourself and will cost way less to do it yourself.
The prop on the other hand will be a definite recommendation. Whoever is responsible for the boat props needs a better solution. I think it may be the manufacturer that’s selling the kits to the resellers though as I know they do the 300a ESC as well.

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Whats about warranty if you open the motor by yourself?

Really? I’d guess a coating of the insides of the motor is all that’s needed for protection.

Can’t see it changing transport regulations. Then a greased geared hub motor would also be stopped as well as any cordless drill with greased planetaries.

The good thing would be that the manufacturer cannot claim void warranty due to opening of motor and there would be no risk for the more brutal users damaging seals and bearings when opening.

As i said, could be wrong but it happens we at work a good bit

What are you shipping at your work?

Coating only provides a bit of resistance and eventually dilutes. That’s why you want to fill it up. Many of the gears that ship out of China actually aren’t greased and you end up greasing them after purchase.

They wouldn’t really know if you opened it or not. Check screws for loctite, if they do have it, replace a bit and they’ll never know.