I rarely pedal. I'm working up to it. I have a lot of stop lights on my commute. I may need to look at my speedo settings too, I did change to a bigger tire. But it shouldn't matter what type of battery since the watt meter is just measuring what power goes into the controller. I did pedal more this morning and only used 1.44ah over 4 miles, so that would be a little better.

I have 11 lights, 2 stop signs.

That explains it. Once you start pedaling more, you'll see a big jump in the number of miles you can travel per AH. Per the logs I keep with my CellLog 8, I'm getting anywhere from 4.58-5.89 miles per AH on my TS LIFEPO4 pack, but I'm pedaling all the time (and often grateful for the granny gears on my bike when trying to climb the steeper hills here).

You aren't using a direct drive hub, right? So you have the ability to use the gears to your advantage. I run flat out at 19-21 mph and I don't have much pedal left at that speed. I think I need a bigger front sprocket.

You're right, I've got the Currie conversion kit installed on my 21-speed mountain bike.

I only get 1.6 to 1 mile per 1AH because I got a motor that takes a lot of energy and I weigh about 250lbs.

But keep in mind that a stock Currie or Currie kit does not use the gearing system at all. So your improved mileage per AH is 100% due to your own personal efforts peddling and the speed you travel. Lets face it your peddling with your motor assisting, whereas. yopappamon is motoring with a only very little peddle assist. This is totally different and can not be compared for AH usage. So no matter what motor setup he/she has it will not change unless they put in the work or just except the high AHs usage per mile. It's a fact of life (ebiking). Nether way is a wrong way I am only stating that they are not the same way to use an ebike.

Shouldn't we be talking about miles per wH, not AH anyways? 1 ah on a 48v pack is totally different than 1 ah on a 24v pack.

True, but most marketing on ready-made e-bikes and conversion kits use mileage numbers that include rider input via the pedals. Truthfully, I would hope that the majority of e-bike owners are pedaling and not simply using the motor only.

Geekybiker,

You're right, the general method used to determine efficiency is to calculate WH/M, which will vary depending on terrain and riding patterns as well as the e-bike's motor and controller. Clearly the Watt Hours available varies by the size of the battery (I believe you calculate WH by multiplying V x AH). To calculate WH/M, you need to ride to a safe DOD to determine the number of miles you can get in any particular terrain (clearly, weather, especially wind, can have an affect, too). My battery pack is still in break-mode so I've not taken it down to safe DOD levels yet to calculate my WH/M. I've got to order a Turnigy watt meter/power analyzer for my handlebars. However, given the levels of power consumption I've seen in my rides to date, I would guesstimate that Ill be able to ride 27 miles and still be at a safe DOD (yes, that's with pedaling--I always pedal). Using that figure to plug in to the calculation, I get 17.7 as WH/M (V x AH ÷ M).

So by that formula we are not that different.

The longer, not too many stops, some pedalling:
8.78AH / 22.5M = 0.390 AH/M x 40V = 15.6 WH/M (40volts being that actual voltage of the 36v cells)

The work run with lots of stops and minimal pedaling:
1.88AH / 4M = 0.47 AH/M X 40V = 18.8 WH/M

I just did a 10 AH ride. My weak cell was 3.28v when I got back so I guess it's not that weak.

On my bike, I can either use 1AH per 1 mile or I can do 1 AH per 2 miles. It just depends on hard I floor the throttle. Not sure if your bikes are the same way or not and that's without pedaling at all. Also, headwinds play a lot bigger role than you realize. I can burn an extra 1AH per mile just on a headwind.

They just delivered my Cell log 8's and my second battery medic. The cell logs are a log smaller than I expected. Especially next to the medics. I might have time to hook them up tonight.

Horrible day to ride a bike today in my city. Wind was like 20 or 30 mph and the damn lawn sprinklers were blowing water in my face.

It's windy today here too. and it rained night before last. I had to get up at 4am to cover the bike (i have no garage). Then later that day I looked at the bike, and my battery box was falling apart. Apparently the cd case I was using is only pressed together and the bumps have been working it apart. I pressed it back together and now have a leather belt wrapped around it keeping it together. So much for my bright idea.

The longer term plan is to make it so I don't have to open the box much. Charging connectors on the side. Either a window to see the watt meter, or mount it on top. Same for the cell logs.

If you don't want to use a ready-made, waterproof case (like the Pelican cases), I would suggest you look at marine starboard. Even though it's a plastic, you can cut, drill and route it without worry about ruining saw blades and bits. It you don't have tools, you can buy pre-cut starboard at fairly reasonable prices on e-bay. I have my CellLog mounted to the outside of my case, in a metal box that has a see-through window. Just make sure to waterproof everything.

or just get a bag on the back. My topeak bag has been holding up pretty well so far. Going on 2 years with it.

Got the cell logs wired. I think I might wire the alarm outputs to a buzzer outside the box and leave the monitors inside.

If you haven't done it already, just remember to modify the CellLog to avoid having it draw all its power from cells 7 and 8. I linked to a photo showing where to solder a small copper wire to fix this issue in the thread on CellLogs. This fix is courtesy of SpeedEBiker, who was an early adopter of the CellLog 8S.

https://www.bikeforums.net/showthread...log-8s-monitor

I'm only using 6 cells per celllog. So I have nothing connected to 7 or 8. I was wondering where it got its power since I was wanting to add a switch to turn them off without unplugging them.

I tried to start using them on the way into work. I didn't create the log file to start with so it didn't log for the 4 miles in. I took off the afternoon and went for a 20 mile trek. These are the logs from it.






So I did 24 miles on the charge 10.7ah. The winds were very high today.

Check out the table view, too. You'll see exact information on each cell and overall voltage. I really think the CellLog is a wonderful piece of equipment and very affordable.

After the ride today, I noticed the battery box was falling apart. The corners were broken, no salvaging it. So I picked up this Avenir case from Dicks sporting goods. The batteries fit exactly.

wow, that looks pretty good. How did you keep your voltages so flat? Did you let off the throttle if it got around 2.8v or did it never get to that point? I'm using probably twice as much current on my controller as you so maybe that's the difference. Actually, I do remember that my batteries only sag to about 3.05v under 20 amps so maybe if you only use 1C, it looks like that.

Were you flooring the throttle the whole time? What would happen if you floored the throttle for say 15 minutes straight? or have you tried that?

My controller never puts out more than 15 amps that I've seen. The area on the chart after 50 minutes is up hill full throttle. Not a big hill, but a long grade. I don't floor it off a stop, I tend to gradually give it throttle and pedal.

My new battery arrangement.

I bolted a piece of wood through the bag to the bike rack. Wrapped ties around it to anchor the batteries.


Battery bundle




Battery bundle strapped down to the board.




Watt meter in the side pocket, controller in the other side pocket.




It's much more stealthly now. But I've found that the board in the bag seems to amplify the motor chatter quite a bit. I should have put some rubber in between them.