Front hub kit overheating and waterproofing questions

[LM2855OR]

I installed a Bafang 48V 500W front hub motor, 48V 17.5ah Hailong battery and a controller that can supply 18 amps (https://www.amazon.com/gp/product/B07N3V6PM8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1&psc=1). Bike has steel fork, torque arms and disc brakes for safety.  The kit came with almost no documentation and I don't want to damage the motor through my own ignorance!  So I've got a few questions:

1) How to prevent overheating on hills: I realize that the motor rating isn't totally accurate because it can output much more than 500W, but I'm still concerned about tackling long or steep hills without overheating the motor.  I've read about electric motors performing poorly at low RPMs, so just going slowly sounds like it might be counterproductive.  Aside from touching the motor periodically to see if it's hot, can you tell if you're overtaxing a hub motor?

2) Waterproofing: I have to commute a long distance to an outdoor research site in all weather, and I have read that thumb throttles are vulnerable to water getting inside and shorting out the controller.  Has anyone experienced problems with water entering batteries, displays, controllers or anywhere else with this type of kit?  

3) Weight issues: Total weight of me and the bike with my work equipment is 175lb, and so far I've had no problems with the performance of the motor. My husband is thinking of getting the same kit, but his total weight would be about 235lb.  If you have experience with using a similar 500W motor at this weight, did you feel that its performance on hills was adequate?

Thanks very much for any advice you can share with me. I have been car-less for 10+ years but I'm new to e-bikes.  It's made a huge difference in the time and effort it takes to get to work and back home.

*Edit: Added location to profile and link to conversion kit

 

[Drunkskunk]

Welcome to the forum.

What type of kit do you have, and what brand? The type of motor you have makes a big difference, but in general, there are two types of hub motors: Geared, and Direct drive. Both will make some noise when they have to work harder, such as climbing a hill. The louder the noise, the harder they are working.
Geared motors make more torque, so protest less, but they will overheat faster. Direct drive make less torque but also can take a huge amount more abuse easily and will overheat much slower. In both cases, listen for the sounds, and if they sound like they are struggling, and your speed has dropped significantly, stop, check their temp, and adjust your path if they are getting too hot. The magnets in both types of motor are safe up to 80°C. They will be too hot to touch long before that.

Your stated weights don't sound like much problem for most conditions, but that's subjective. One man's hill is another man's mountain. 10% grade is should be fine, for most motors.

The biggest risk in rain isn't the throttle, but since you asked:
A 3 wire throttle is fairly low risk. I've never had one harm the controller by getting wet, but they can stop working until dry. Mine had to go under water when I slipped in a river before it was wet enough to stop working. They are 5 volt only and with enough internal resistance that a water short does no damage... usually. it also takes a lot of water, with most designs, before enough can get in to short out anything.
Those controllers that have more than 3 wires, indicator lights, or power switches often have full 48v battery voltage in them. Water getting in here can short out the controller, killing it. I just this week blew up a controller like that after my bike got caught by a storm.

There are a few things you can do to prevent this. First, make sure that all wires that enter the throttle, the controller, motor, and the battery do so from below. Having a low spot in the wire before it enters a device is called a drip loop. it prevents water from running along the outside of the wire and entering past any gap in the seal. See pics bellow.
Second, pop the throttle apart and add some RTV silicon gasket maker to all the seams.
Third, while it's apart cover all the connections with Conformall, a water proofing agent meant for electronics. You can also usually use clear nail polish, but there are a few types that aren't waterproof or that are conductive.

the 2 biggest risks from rain are water entering the motor, shorting out the halls, and water getting into the controller. In both cases the best prevention is to make sure the wire enters from below, as with this pic:

 

[motomech]

I've read about electric motors performing poorly at low RPMs, so just going slowly sounds like it might be counterproductive.

Very perceptive as this is the crux of the matter w/ hub motors.
A common mis-understanding is when folks equate an electric motor w/ a gasoline engine. The way the two produce "torque" is quite different and any assumption of what is ok for a ICE is ok for a motor should be avoided.
W/out going into the technical details (Of which I'm somewhat foggy), I will state the 1st Law of hub motors;
When the motor rpm falls below half the max rpm, the motor starts to produce more heat than locomotion.
So when tackling challenging hills, it's all about conserving momentum. So the idea of going up slowly or running a low power controller (or setting) is exactly what one doesn't want to do.

Although you haven't filled out your profile and we don't know what ambient temps you might be dealing with, your concern about overheating the motor is probably needless on a 48V/15A system. My experience w/ geared hub motors when over-exerted has been, in order of failure;
1) the phase connectors melt.
2)the phase wires melt.
3)The controller gets too hot and fails.
4)One or more of the motor's Hall sensor fails.
I've never had a geared hub motor "overheat, and the ones I use are smaller than yours and the rider is a lot larger.
The way to protect them is the hill strategy. If, on the way up, you get a sense the bike is going to "lug" to a stop, you are probably in violation of the first law and it's time to jump off and push.
I suppose very long hills on a hot day could heat a geared hubbie to the point of cooking it, but I've never experienced that, even in Az.
I do know that over-volting will destroy a geared motor, folks here have done it, but you are a long way from that. And remember, your frt. mounted motor is in the air-stream.

As far as the ingress of water is concerned, if you ride in water levels at or near the axles, it's going to happen. But it drains out and the internal heat evaporates what's left. Of more concern is winter riding where salt and grit can get inside, but since you haven't filled out your profile I don't know if this concerns you. If so, an end-of-season dis-assembly and cleaning is in order.
As for the rest of the system getting wet, well, there are systems that use "water resistant" connectors, but I doubt any ebike can be truely water-proof.
On the few times I have caught is the rain, I had a lg. poncho that I could drape over most of the bike (and me).

 

[LM2855OR]

Thanks so much, drunkskunk and motomech, for your thorough replies. I live in western Oregon, so it's rainy here from Oct.-May, but it rarely gets excessively hot. I added a link to the kit to my post. There's not much information about the type of hub it is, but I believe it's a geared hub.

I'm going to take your suggestions for waterproofing, and appreciate your reassurance about the potential for overheating!

 

[Drunkskunk]

I followed that link, and good news. Your motor is a Bafang geared motor, and the seller is Bafang themselves. Bafang is one of the better Ebike motor manufacturers, and sell most of their product to big companies to build ebikes with.

There is a lot of information out there on the Bafang 500w motor. It's a well known, well used motor.

 

[john61ct]

Ideally the motor has a temperature sensor embedded.

Some controllers will de-rate / limit current as the motor internals start to heat up.

If not adding a CAv3 will do so, along with dozens of other features.

Also, investigate if your motor can work with statorade.

 

[dogman dan]

First of all, the way you overheat motors is not low rpm, creep all you want on flatter ground. What kills your motor fast, is overloading it till all it can give is too low rpm. You are both fine on weight load, which should be kept under 300 pounds for bike, battery, yourself, and gear. 300 or less, you will be able to climb long hills up to 8%, while keeping rpm up. Aim for 15 mph up really long hills.

Mount your controller in as dry a place as possible, but do not smother it in a bag. I liked controller behind and sort of under my ass, and the plugs under the seat, with non waterproof kits. Riding in the rain, a half throttle allows your hand to cover the crack, keeping rain out of the throttle. Bag the seat and the throttle when parking in rain. Drip loop is all the motor needs