I just picked up a used e-bike recently that I am very happy with. I was just wondering how the battery indicator works on it since it just has full or empty. Does it light up empty when you should stop riding or does it have a reserve?
Also, to run at 48v (will upgrade to a ping battery eventually, how do you contact him outside of ebay,) do you just have to wire in a resistor in series to keep the indicator lights working?
My top speed with a 700c X 32 wheel (bike shop reccomended that size and not skinnier which stinks b/c they carry a 28c that is half the weight,) is 22.5 mph and it seems to even do that when pulling 100lbs of dog/trailer (reason I got it to begin with.) It spins to 25mph with the wheel in the air. So my assumption is that 22.5mph is the max with the current batteries and I just have to pedal harder with more weight. Because of that I let off the throttle going downhill to save energy and thinking it may even act as a brake at higher speeds.
You are very perceptive. Indeed, the cogging effect of the motor does slow down the top speed down hills, but it won't of course stop you. Alas, it doesn't charge the battery even though the cogging effect is making electricity.
The battery indicators will light up about 2 miles after you should have stopped riding. Opinions vary when you should stop, but it seemed to me like the lights go on when you are at least 90% discharged, which just about all agree is too much. Stopping when it lights up, at least avoids the dreaded 100% discharge. Some say never go past a 50% discharge, and they are right, for a maximum battery lifetime. I find a 75% discharge to be a good compromise. Figure out how far you can go before the light goes on, and try to ride a few miles less than that. A speedo helps a lot for keeping track of how far you have left. The wireless speedo's I tried worked sporadicly, but the wired ones I use now work fine.
Ping posts his email on the auctions, but by the time you buy he may have a website up. Once you go lifepo4, forget about the trottle lights, there won't be enough voltage sag happening to make em work in a meaningfull way. Anyway, you will still be wise to be only using about 50-75% of the capacity, and can track that roughly by mileage, and a fudge factor for wind.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
I find that with my BD-36 (which draws more amps then the BL-36)the light will begin to turn yellow when the motor is under load, like when accelerating or going up a hill, at something like 50% to 60% charge remaining in the batteries. It's at about the same point where you can start to feel the power start to decrease. The light is turning yellow due to the volatge sag under high amp draw on the batteries. This would be less effective on the BL-36, which draws about 30% less amps.
If you run it until the light stays yellow even when not under load, you've gone well past 50% discharge, meaning you're shortening the life of the battery pack somewhat. If you're paying attention, you can feel the power start to wane when climbing hills and that is usually a good indication as to when to stop riding if you want to maximize battery life.
If you've got a volt meter, the resting voltage (after the battery has been off the charger or not used for a half hour or so) will give you a good indication of the state of charge. I've got a table of battery voltage vs percent charge that I will post later.
Your yellow light must go on much earlier than mine. Mine doesn't light up till you are way below 30 volts on a BD36. Pretty well past where I want to stop for me. Imagine that! The throttle lights aren't accurate. Who woulda thought that from WE stuff? I consider mine pretty much an on or off indicator with the lifepo4. When I talk about the light being on, I mean on continuous.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
So does it help to let off the throttle when going down hill? And does it limit my top speed when I do? Not that it matters just curious because I can get going faster on some hills on a heavier bike without even pedaling, but the average speed on the ebike is still alot better.
That seems silly, can a resistor be added inline with one of the wires to make the gauge actually useful? I'll have to see how much is involved in building a voltage gauge with 4 or 5 leds to give a better idea.
I'd just like to figure out how far I can go safely. Is the discharge pretty linear? Like if it took 25% to go 7 miles then would it take 50% to go 14? I'm timing how long it takes to recharge and guess 85% efficiency with the 1 amp charger (read that from someone else that was guessing too.) I measure the voltage too but don't know how that drops off, that chart would be neat to see.
I also don't know if I would notice a loss in power since I pedal along with it. I also do not know yet if pulling an extra 100lbs of trailer/dog affects the range much or if I just pedal harder to equal it out, I do know I pedal harder, just not if it's hard enough to make up the difference, especially uphill.
Help with what specificly, letting off throttle downhill? If you leave it on, you will go down the hill faster, but you won't use too much juice if you can roll nearly the same speed without throttle. Throttle off on downhills will slow you noticeably. Just a tiny bit of throttle should let the motor roll without the cogging resistance at slow speeds, but to remove cogging at higher speeds will take more throttle.
When you peadle the bike on flat ground with the throttle off, you can't go as fast as you could before you put the motor on. Part of that is weight, but most of it is the cogging force. I can't maintain much more than 10 mph with the throttle off on my bike. When I am low on battery a long way from home, I give the throttle a tiny tiny bit, just enough to ease the cogging resistance and then I can goe miles using very little battery, but can stand to peadle home without the cogging.
discharge will be as linear as your riding is, IE if you ride full throttle at all times like I do, range varys little. But if the ride out is wind at back, and the ride home is wind at face, then the ride home will take much more power.
You should get the hang of it pretty quick, and soon you will feel it when you cross the line at about 70% discharge, and start going a lot slower at full throttle. Like I said, a speedo really helps with this, so you can compare rides better. Charge time is a good indicator of how empty the batts were once you know how long it takes for a charge after a standard ride you do often.
Packing weight will definitely cost you speed and range, but towing and hills is what ebikes are for. Really steep long hills can melt a motor though, so if you can't keep some speed up, maybe find a different route with the dogs.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
Thanks once again, that makes sense. I'll have to play around with the throttle going downhill to see how much to give it. If my speedo is somewhat accurate my top speed is 22.5mph and uphill I slow down to 19 or 20. I don't know about downhill yet since I have been riding in the dark to work and save my helmet mounted flashlight batteries in case my main light goes out. I'll ride it again in the day this weekend (didn't have speedo on last time.)
That's a great tip on a little throttle to remove cogging, I had no idea it would slow me down that much. The wired speedo was a great tip too, I had a wireless one on my other bike and I would look down sometimes as it was reading 0mph and would be missing up to a mile on the trip. I went with a Sigma 1606L with backlight and cadence for $35 and I love that one. Also got a 2nd bike kit for $16 and it keeps track of them separately. I've got the cheap wireless on the ebike atm though.
I guess I'll just have to try pushing it just a bit farther every weekend and check the batteries/charge time. Once I get up to speed the motor doesn't feel like it's doing much even uphill, but I know that must be really deceptive because it also doesn't feel like I'm still going 19mph uphill, more like 12.
One more additional question I couldn't find by searching. I switched to road tires but in a wide enough tire for the front all they had weighed 660g for the front so I got that. If I ordered a Panaracer tire that weighed half that would it make much difference? I know rotational weight makes a difference of at least 3 times what stationary weight does (on cars they say 10 times,) but when your already talking 32lbs of bike+60lbs? of motor I don't know. Although the front tire weight is what the motor is turning.
Sorry for all the detailed questions though, I'm a curious person at times.
Once you are motorized most issues of weight become meaningless untill the motor stops working. Then you get to peadle home with a 75 pound bike and a motor that drags like a flat tire. Uphill for me too since I live up high. The motor hub is so heavy that I doubt tire weight matters much. Weight of yourself, and weight of the batteries makes a difference though, especially if hills are steep.
Rolling resistance of tires makes a huge difference, so a lot of long range riders use high pressure, slicks and such to get that as low as possible. Speed affects range more than anything, range at full throttle will be half that of 10-12 mph. For me though, I didn't spend $1500 to go 12 mph! I like 25 mph a lot, and get a little worried doing much more unless on perfect road.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
Here's a voltage chart I use for my 36v SLA battery pack. It is 10% higher than the "factory" spec for SLA batteries to account for the slightly higher resting voltage that my WE packs sit at when fully charged. I really haven't tested the bottom end of it thoroughly because I rarely run my pack below 50%.
Voltage Percent Charge
39.46 100%
39.12 90%
38.75 80%
38.35 70%
37.94 60%
37.51 50%
37.08 40%
36.61 30%
36.15 20%
35.68 10%
35.19 0