Watt output diminished when it rains

onespeed

100 mW
Joined
Feb 5, 2021
Messages
37
I have 2 ebullits with conversion kits. They are both running Crystalyte hub motors one is a front hub and the other is a rear hub motor. They are both running off the same 2 60v batteries that I swap out in rotation. I use them to deliver beer, so I am carrying a lot of weight through my shifts.

The one with the front hub kicks out 2200 watts fully charged off the line - when it isnt raining. As soon as it is a sustained rain for an hour or so, wattage kicked out drops down to 50%. I can barely get it over 1100 full throttle. When it happens I switch to the rear hub bullitt and ignore the problem until the next day.

The next day there are no issues. The front hub bullitt kicks out as it is supposed to. I am running CAs on both of the bullitts, so I can see the numbers on the screen.
 
If there is no slippage of the front hub because of the wet conditions (which will reduce power usage limit to the point at which traction breaks, which may be at a lower point uphill than down), then the next possibility could be water on the shunt connections (usually the actual shunt measureing wires) to the CA, causing an incorrect current reading which then causes incorrect power calculation and display. The actual power used will be correct, assuming there are no CA limits being engaged that change this (indicated by capital letters on the diagnostic screen's lower left), it's just the displayed info that is wrong.

The latter can be tested by wetting the shunt and it's connections, one at a time, to find the leaky / faulty area. The same can be done with all the wiring within the system if necessary.

The former can be tested by wetting the road to be travelled on just enough to cause traction loss without wetting the system or wiring.

There may be other possible causes, but those two I've experienced myself on the old long cargo bike CrazyBike2 in various conditions.
 
Insightful comments, Amberwolf. Thanks for sharing your experiences and ideas.

OneSpeed, does it FEEL like the bike is only giving you half the power when it’s wet out? Or are you hiding by only the screen. The difference in acceleration under 1100 and 2200 watts should be stark.
 
amberwolf said:
If there is no slippage of the front hub because of the wet conditions (which will reduce power usage limit to the point at which traction breaks, which may be at a lower point uphill than down), then the next possibility could be water on the shunt connections (usually the actual shunt measureing wires) to the CA, causing an incorrect current reading which then causes incorrect power calculation and display. The actual power used will be correct, assuming there are no CA limits being engaged that change this (indicated by capital letters on the diagnostic screen's lower left), it's just the displayed info that is wrong.

The latter can be tested by wetting the shunt and it's connections, one at a time, to find the leaky / faulty area. The same can be done with all the wiring within the system if necessary.

The former can be tested by wetting the road to be travelled on just enough to cause traction loss without wetting the system or wiring.

There may be other possible causes, but those two I've experienced myself on the old long cargo bike CrazyBike2 in various conditions.
From-A-To-B said:
Insightful comments, Amberwolf. Thanks for sharing your experiences and ideas.

OneSpeed, does it FEEL like the bike is only giving you half the power when it’s wet out? Or are you hiding by only the screen. The difference in acceleration under 1100 and 2200 watts should be stark.

It definitely is less power. I know what my rate of acceleration is off the line and I know the numbers that should be there with a fully charged battery. When it starts raining, torque off the line is cut in half - and it is not the front wheel spinning, which is a real danger on a bullitt. So switching bikes is not a hard decision, to get performance back and to be safer.

At first I thought it was a quirk and a one-off. I completed my shift running at half power. The next rainy shift I paid attention. It started off fine, but after riding in the rain for a while, riding off a delivery stop, the throttle delivered only half of what was expected. I went home and swapped bikes to be more efficient with my time and to spend as little time as possible in the rain.

So the behavior can be replicated under the same conditions. The rain is the linking factor.

Running Crystalyte 2535 front hub tied to a phaserunner. Where is the shunt you are talking about?
 
Do both bikes have the same battery? or is one battery weaker/smaller than the other?

I would suggest you try swapping throttles because one of the throttles may be sensitive to humidity.
 
neptronix said:
Do both bikes have the same battery? or is one battery weaker/smaller than the other?

I would suggest you try swapping throttles because one of the throttles may be sensitive to humidity.

I use the same batteries for both bikes.

When I swapped bikes I just moved the battery over.

The throttle thing is interesting to consider. 1 is thumb and the other is twist. I might have another thumb or twist sitting around.
 
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