Wallonthefloor

I got the detroit bikes e sparrow, Im around 180 pounds and with the hills I live on Im worried I could burn out the motor. I try not to put too much strain on it im always pedaling as hard as I can but uphill and in full assist I can hear the motor, Im not sure but I think it shut off on me at the top of a hill. Ive rode it once cant wait to get back out again, but what I want to do with it is get a trailer and haul my big pitbull to the park, this will increase the weight 60 or 80 pounds but only for a short distance of a mile and only a small hill. Is the motor going to be okay?

cat0020

There are some steep hills in Pitt, it would be better if the bike has multiple speeds; but I'd imagine if you're not sustaining the PAS operation for extended amount of time.. maybe 10-15 min. of continuous, sustained high power output.
You can always get off the bike and take a temperature check when you get tired of climbing, check battery, wiring, controller and motor.

2old

The bike could have some sort of temperature shut off, and stopped for that reason. Your bike has a geared motor (look at the tutorial on ebikesca for definition) which means there are reduction gears inside, and inherently louder than direct drive motors which have basically one moving part, the hub. A rule of thumb cited by many (works for me) is to put your hand on the motor; if you can't hold it there for 10 seconds, the motor is too hot. Bottom line, keep pedaling with your dog and IMO you'll be fine. Just watch the hills.

surveyor6

When I was in the USMC, vehicles, equipment and aircraft had a “Normal” (continuous) power rating and “Military” (temporary) power ratings.
- Military power was time limited. Normal engine redline is 4,000 rpm. Military power setting allows you to rev to 5,000 for a maximum of 15 minutes.
- Motor makers should provide safe power settings for continuous operation AND power settings to be used for only a limited time period, such as when climbing a hill.
- You may create such an “operating envelope” yourself, and then adjust it using the methods mentioned in the posts above.

Doc_Wui

Pittsburgh has some huge hills. You cannot expect to throttle up them without helping the bike out with pedalling and being in low gear. But the E-sparrow is single speed bike with a 250W Bafang. I think you're close to a meltdown riding alone. It's not enough bike with a trailer and dog.

hydrocarbon

For sure.

The slower a hub motor spins under its optimal range, the less efficient it gets; energy used for propelling the bike decreases and energy turned into waste heat waste heat increases, which is very hard on the battery and motor. Trying to haul a heavy load up a steep hill will easily overload a 250W hub motor unless it has ridiculously low internal gearing.

2old

Did anyone read the question? He asked if he could pull his dog (on a trailer so the amount of energy required is lessened) ONE mile with one small hill. I say that as long as he pedals, yes, and he can check the motor's temperature half way up the hill with his hand. Obviously he realizes there is a problem with steep hills, but his system may have a temp cut off. I had a 350w Dillenger front hub conversion that was used to ascend pretty steep hills off road and would cut out occasionally in hot (100 degree) weather. Never burned out the motor though.

kayakindude

We pull a dog too on a tandem, combined weight is probably 380 pounds. Only a few larger hills and most rides average 1500 of climbing or less. Our motor has never cut off but we frequently leave it on the lowest setting, which I think is 25% output. I assume most systems have adjustable power settings so if you get concerned you could always lower the output.

hydrocarbon

2old
You can absolutely damage a hub motor on a 1-mile climb if it’s overloaded at low RPM, but a more immediate problem is that a 250W one is going to simply stall out on a steep climb with a flatland-geared singlespeed pulling a trailer.

2old

The first post says the terrain is flat with one small hill. That's what I was responding to. I used to haul my daughter on a "tag along bike" behind me (didn't find out for awhile that she thought she was a passenger); similar 70 - 80 pound weight, and we went up and down hills off road all over the place, 10 - 15 mile rides on a pedal bike. I'm old, but bet that ride is easy without the motor.

hydrocarbon

Fair enough. Should be fine if the hill isn't too steep.

2old

OP; The other rule of thumb for ascending is not to let your speed drop below half of the top speed of your bike (9 - 10 mph) since too much energy will be turned into heat. If your system doesn't have a speedometer, a stand alone one will do.

MNebiker

I'm really inclined to agree with Doc Wui - a 250W single speed flatland bike is not enough bike for the proposed use. The OP indicates that he has some reservations even without the trailer and dog added, and is already pedaling "pedaling as hard as I can" to make the hill. Only a mile can become a long distance.

But the OP already owns the bike - the only thing he can do is give it a shot and see what happens.

Note also that the battery management system might shut it down if the battery voltage drops too low under heavy load. This is only a 250W motor, but it is not a large battery. Make sure that the battery is at full charge for the trip.

2old

There should be a rule that individuals read the OP's statements before commenting or at least say they didn't read anything and just "shooting from the hip". The OP is talking about a one mile ride on a flat trail with his dog in a trailer. Wish I had a chance to bet some money on whether it'll be easy or not. Easy peasy!

Doc_Wui

Okay. Flat road with a trailer? Better get a mirror and point it right at the dogger. He won't feel the load, and will worry that the trailer fell off,

MNebiker

In reading the OP's post I seem to see the words "hill," "hills," and "uphill." He also seems to be concerned about making it up one of those hills and thinks that the motor may have cut out on that hill. I don't read that as a simple one mile ride on a flat trail. Now he may be OK - if so, fine, but I still have reservations.