Just wanted to know if it would be possible to pull a 500 pound bike plus 165 pound rider down the road at 55 to 65 mph with a brushed electric 48 volt, 7hp continuous, 4200 rpm, 133 amp motor?? was thinking about gearing it 4 to 1 with a 24in. tall rear tire, any thoughts?? I'll be using four large lead acid deep cycle batteries that put out about 225 amps/hr and have 100 amps in reserve. Any ideas on how long the silly thing might last at say 40mph in stop and go traffic??

Its very doubtful that you could get upto that speed at 48V with a 7hp motor. Even with an etek/perm132 type motor, you'll need a higher voltage, and taller grear ratio. I'm running a 4:1, but I also have a 18+Hp 72V motor.

Is the 133A max? what is the max horsepower? do you have a KV rating on the motor? (volts per RPM).

If you are wanting to go, more like 45 or so, that's doable, with a taller ratio. If you build a low rolling resistance bike, and don't gun it, and can average about 100Wh/mile, then lets do the math.

I don't think those bats are 225Ah... those would be huge. That might be max, but what is the standard AH rating? 55? 75? What is the 20hr rate.

Here's how you calculate:

Take the Ah of the batteries (lets say 100), and the voltage of the battery pack (48V) ... 48*100 = 4800Wh. If you can only go to 80%, thats 3840Wh usable. Take another 10% out for efficiency... thats 3456 Wh or so. Now, say you can do 100Wh/mile... and you have 3456 Wh.... 3456/100= about 34 miles. not bad for 48V.

Take your numbers and retry the calcs.

Sorry, I meant to say that my batteries are 12V deep cycle batteries that have 205 amp hours in reserve and another some thing ....some thing to ad to that??? they weigh about 60 lbs. each. Any way the only other info I can read on my motor is FR 49, AMB 40 C and nothing else. It's a GE motor MOD 5BC49JB1127, havent been able to look up to much info in it though. Was wondering if I geared the thing with 5 to 1 would it help the range any??? Thanks

well, the motor is 48 volt, 7hp continuous, 4200 rpm, 133 amp motor....Continuous sounds decent. How heavy is it? You don't have to use 48V, I'd go with 72 to get the speed you want, but its already 4200RPM at 48V...

I need more info on the batteries, like part number.... because I want the AH rading. Not the reserve, CCA or CA. Just how they sell it, 12V XXXAH. 60lbs sounds like a 50-60Ah battery.

5:1 would help with the range, but would hurt top speed.

I am running on an Etek at 48V, my bike is geared 3.6 : 1 with a 24 inch wheel and it tops out at about 58 MPH and has fair acceleration. 200lb rider 200lbs of batteries and the bike has to be over 200lbs so I should be pushing pretty close to the same weight as you. My batteries are 115AH and weigh 50lbs on the nose. I haven't had my bike out to test its range yet.

The part number of the batteries is Maxx 29, they're a Maxx Marine Battery and don't know if there worth getting, battery is the most expensive you can buy at my wal-mart . I'm just starting this electric bike stuff and don't know a lot, I've heard of lithium sulfur batteries to be promising and also the nano technology stuff that seems promising as well but why hasn't any of this stuff come to be?? An etech motor that can push a 500 lb plus bike to 55 mph or more, sounds good to me. Has any of you seen the mileage contests, at least back in the early 80's, where they were pushing 300 and 400 mpg with aerodynamic bodies and all the other good stuff. Any way I was thinking of making a body for the bike to help out with top speed, any thoughts???? Thanks for the help

frodus, I think the batteries have 125ah, don't know for sure but wasing reading about how good these batteries are on another post, any way that means by your calculations the bike should be able to go 43 miles but.... have a feeling I'll never be able to do that I live 17 miles from work so it's a 34 mile round trip and I'd want to go 55 or 60 for the first part and then 40 or 45 or so for the rest. Know of any cheap NiCd, NiMh, or Lipo batteries

how much do those things weigh? sheesh......

As far as fairings, I got a bike that had a full fairing to start with. We might fill in some of the fiberglass.

pics.evfr.net (we're really close).


As far as Lithium Sulfur and Nano... these are things that have only recently been developed, its going to take a couple years until we see them on the shelf. The scientists are still developing the technology. Now they have to scale it up for production.

500lbs+ and an etek seems a little underpowered to me... is that weight with rider? or without?

you don't want to use nicd, they aren't that great for what you get out of them, and they degrade....

Nimh are hard to find, and expensive

Lipo batteries:
there are several flavors...

Lithium Cobalt: Bad, stay away from these, they catch fire.
Lithium Polymer: Volitile
Lithium Iron Phosphate: In its infancy, and rather expensive...

stick with lead, you aren't going to get a pack of 72V worth of lifepo for under $5 at 100Ah and 22 cells to get you around 40 miles or so.