too many things

deacon · #1 (**permalink**) 11-21-2009, 08:15 AM

I guess I have tried so many things, that I have lost my way. There are so many issues with ebikes that my poor old brain can not comprehend them all. For instance, I have been riding my bike a couple of miles to the mall and it does great. I am running 600watt 24 volt system on 36v battery pack. It is only two miles there and two miles back total 4 miles. I always come in with a lot of reserve juice.

So yesterday I decided to ride to the marina. The round trip is only 6 miles. It is up and down hill and those hills are steep. Even with the gasoline bikes, there was risk of stall. The ebike didn't get to that point, until I had exhausted the batteries. They just did not have enough reserve to handle all those steep hills. I was running the equivalent of 19ahs but couldn't even get 6miles without the batteries getting flat. The bike did not shut down at all. It didn't even appear to want to shut down. What happened was that it just went flat. After five and 3/4 miles I actually had to get off and push it up the last hill, but once it got to the level ground again, it took right off at a snails pace.

I am really disappointed in the battery performance. I prefer this drive system over any gasoline powered bike that I have ever ridden. The batteries are making me crazy though. Today I am going to test the bike back on 24v as it is supposed to be. Maybe the 36volt is causing the batteries to drain more quickly, since I can climb big hills with lots of power. It is hard to get the bike slow enough so that I can pedal along. That might be the real problem with the quick drain. It might be that I am relying too much on the motor and not doing any helping at all with the battery stress situations.

I also have a bike set up with a 36v controller. After I get this 24v checked out for range, I will try the 36v over the same distance and see how it fairs.

**Bikeguy Joe** · #2 (**permalink**) 11-21-2009, 09:29 AM

I will comment that with my battery powered planes, the higher the voltage, the less run time I get. Even if I reduce throttle, the higher volt pack don't last as long as the lower volt packs.

**BarelyAWake** · #3 (**permalink**) 11-21-2009, 10:07 AM

hmm... not that this is my area of expertise or anythin' lol - but when I was lookin' into electric/hybrid boats I noticed that many of the "rheostat" style throttles reduce voltage to the engine through resistance, which doesn't conserve power as it wastes it through heat generation. There's no real significant difference between say 1/2 throttle and WOT as far as battery drain is concerned.

Early designs worked around this wastage by stepping the voltage, tapping one battery for say 12v, two for 24, etc. this caused uneven power drain on the batteries in the bank ofc, but that was dealt with by periodically rotating the batteries so the same ones didn't always get all the load.

Newer throttle controls offer a pulse width modulated control signal which is far more efficient, conserving power at lower speeds but still using all the batteries uniformly - but they're expensive and as a result, not terribly common.

I have no idea if this is common knowledge for you guys lol, most of the electric boat designs I was researching were the late 1800s to early 1900s

**Bikeguy Joe** · #4 (**permalink**) 11-21-2009, 10:59 AM

All my speed controllers are digital.
One of my few submissions to the 21st century.

deacon · #5 (**permalink**) 11-21-2009, 11:51 AM

These throttles I use supposedly have the hall effect. Which is no more than a sensor to tell the controller where the throttle is. At least that is my weak understanding of it. I am pretty sure that the throttle is not continuous but is in phases. like 1/3 throttle ect... However I have heard that you can use a 5k pot with the controller so maybe it is a resistance type

I rode the 24 bike to the mall and got pretty much the same results but with me pedaling more. I think I also need to increase the tension a bit. The bike seems to speed up for a non throttle reason. I think it needs just a little more tension.