Electric Bike: Distance Problem

physic.dude

physic.dude

New Member
Hi all,
I recently finished my electric bike a few months back. It is built from a razor e300. It is a friction drive, so no modifications to the bike itself,

Anyway, I have given it 2 full test runs (full charge to no charge) and according to a digital speedometer AND a GPS I got about 10 miles at 20 mph with ZERO (that’s 0) pedaling. But since I thought I would like to take this to places in public I wanted to put in a key switch, so I did. (6A from digikey) and after I wired it all up, I plug in the batteries, flip on the switch and... nothing. What happened is that I fried the motor controller due to a crossed wire on the switch. So then I buy a new motor controller and rewired the switch properly. Later I fully charge it and take it for a full test run. I got it to 20 mph but only went less than 5 miles. So I figure it is the batteries, there pretty old so I got some new ones, I installed them, then test and still only get < 5 miles. So now I think it could be the motor controller once more since this one isn’t razor brand, (it sais electric bicycle controller on the side) so I get a new motor controller (same brand as above) and with it I got a new throttle. I pop both in and still I get < 5 miles at 20 mph. next I figured it was the wires to the switch, I had 18 gauge so I replaced them with 14 gauge (same as the original switch used.) but still I get < 5 miles.

Now I am stumped, all I can think it could be is the motor, charger, or a loose connection (least possible)

Does anyone have an idea what I can do?

Please.
:-||
 

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You could always install a HT motor and get 100 - 150 miles for about $2.60 worth of gas and a few ounces of 2 cycle oil. :)
 
Actually, I live in a gated community and little gas vehicles like that are not exactly legal due to the town’s "noise abatement laws".

Electric ones are perfectly fine.
 
Don't know what your battery size is but, 5 to 10 miles at full throttle 36V 12 amp SLA wt 35lbs is normal. SLA batteries weaken with each use and even faster when completly drained 200 to 300 charges is about it. More amp's will run longer but, add weight. To extend the SLA's battery life never completly drain and place on charger whenever you can. Try half throttle and your range will increase. NIHM's will increase range can't remember how much and 1,000 or more charges. Lithium polymer or ion batteries will give the most 3,000 charges but cost around $700 or more for 36V 15 to 20 amp wt 10lbs. Another point brushed motors drain batteries faster than brushless. There's links to electric motors and a electric motor forum on my website check them out you might find some interesting stuff.
 
I tried the best electric bike money can buy in Canada--1500 dollars without the bike --good only for 15-20 miles then you have to charge it -heck with that i might as well pedal so now have gas bikes.
 
nsideus said:
Don't know what your battery size is but, 5 to 10 miles at full throttle 36V 12 amp SLA wt 35lbs is normal. SLA batteries weaken with each use and even faster when completly drained 200 to 300 charges is about it. More amp's will run longer but, add weight. To extend the SLA's battery life never completly drain and place on charger whenever you can. Try half throttle and your range will increase. NIHM's will increase range can't remember how much and 1,000 or more charges. Lithium polymer or ion batteries will give the most 3,000 charges but cost around $700 or more for 36V 15 to 20 amp wt 10lbs. Another point brushed motors drain batteries faster than brushless. There's links to electric motors and a electric motor forum on my website check them out you might find some interesting stuff.
Click to expand...


The batteries are 2, 7Ahr 12v sealed lead acid batteries. (24v)

When they were in the scooter they gave me 10miles at 20mph (full). Exact same with the bike before I put in this switch. Now I get half the distance.

Ps. the bike originally took 8-12hrs to charge, now it takes about 4hrs
 
This is what I would do in your place- completely bypass the controller with a toggle switch somewhere that you can reach quickly. Who knows if that is killing the range or if it is the batterys.
I use a similar scooter motor (250w) on my home made e-bike and only use a toggle- it is geared to only go about 13 mph though, and with the batterys I got, only goes about 5 miles before it slows down significantly.
 
Its the batterys,i had a elctric bike (24v 2 7ah batterys 250watt) and after 75 charges the batterys went from 8hours charging (15mph @ 5 miles) to 4 hours charging (12-15mph @ 1 mile).

Go get new batterys, lots of them and buy em cheap cause they wont last long.

I scraped and sold off the elctric bike and got a gas one now he he 30 mph @ 180 mpg.
There not legal here either.
 
ohhh man i got no advice as far as electric bikes go but i can tell you im frustrated for you buddy what about a quiet 4 stroke a even a quiet 2 stroke with the stock exhaust without gutting it as long as its not leaking anywehere you can hardy hear them either that or im goin deaf at 21 wich would really suck
 
Could be batteries, switch or controller. You'd need to do process of elimination. Easiest is jumpering or temporarily eliminating the switch. A 6 amp switch is way too small for most electric motors unless you are using it with a relay BTW. Next you could try replacing the controller with a relay (rated at least 20 amps) and momentary switch. Would probably run you around $10 at Radio Shack or equivalent. Use that to bypass your controller and throttle. Pedal to start from a dead stop and pulse it to maintain speed. If you get your range back, the new controller is the problem. Get a digital voltmeter and check the voltage of each battery individually after use and when charged. Try to never fully discharge SLAs, and never let them sit without recharging if they are more than 1/2 discharged. OTOH, you SHOULD fully discharge NiCads. NiMH don't care either way and Lithium require special care until they're broken in - jd
 
Friction drive setups are very inefficient for electrics due to excessive drag. Your motor is also marginal for the load that it's under and after 10 miles it was probably super hot along with the controller. Finally the 7ah lead acid batteries should really only give you about five miles under normal conditions unless you were providing lots of pedal assist.

Have you checked out Electric Bike & Electric Bike Kits
Their systems are way more robust than your current arrangement and they are extremely efficient and super quiet. The one below is my brothers 48v Phoenix and it easily gets 10 miles per charge with a top speed approaching 40 mph, it pulls hills with ease. It has almost 4000 miles on it now and just got a new batch of 12ah lead acid batteries.

Marksphoenix.jpg
 
Tell me did you by chance change the tension on the rear wheel. I have recently found that the only tension you need is the weight of the motor pressing down. If you use a spring or a tension bar you might have increased your drag enough to kill your mileage. Mine work best when i just have the tires resting on the wheel.

As for friction drive, I also tried a hub motor and found the range no better at all. Is your wheel the eight inch model. I just got one of those in the mail and am about to build a frame and wire it up but with a 600 watt motor running at 36volts.

Bye the way I am 210 pounds and live in a area with a lot of hills and I probably get about eight or nine miles on a charge but I run at 36 volts. I don't use a switch at all. if i did it would be a simple on off switch hidden under the seat. I do agree 7ah is way too small. I run 17ah pulled by a trailer.

most of my batteries never get down to 12v before I charge them. They say below 11.75 volts will damage them. They say that after that they will not hold a charge long. If you ran them all the way down that might be your problem as well. You must live in a very flat area to have gotten that much range to begin with. You might also want to check your bike for pedal ease. If it is harder to pedal find out why that will also kill your range. A dragging brake ect will get youi.
 
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Guys... I’m sure I told you this before but the problem lies between the charger, motor controller, and batteries. This is why, normally it takes about 8 Hrs to charge, but for some reason it takes only 3-4 Hrs.

I think the problem is the motor controller, because when I replaced it after it fried from the new switch is when the problem started. The motor controller that came with the scooter was some unlabeled and unspecified controller, the new ones look completely different form the old. I wasn’t able to by a motor controller form the razor store because they were sold out, but now I just checked and there back in. so, I’ll try that...
 
Use 10 gauge wire and switch to lifepo4. You can get 12v20AH packs at elitepowersolutions.com for $104. You just need to educate yourself on how to use lithium because it's slightly different from lead acid. Once you do that, you will have mega - distance. I recently switched to lifepo4....and oh my God.. I'm doing things on just 1/4th of the pack that I couldn't do using my entire SLA pack. Lifepo4 is insane. And I haven't even found out the max distance yet on my pack. I normally come inside before the pack is done. I figured out that I can go 18 miles on 10AH of lifepo4. Whereas I had a 9AH of SLA and I barely got 3 miles out of it so it's a huge difference...I'm getting 15 miles more range at least and that's with only using half of my 36v20AH Thundersky lifepo4 pack. If I use 15AH , I could go 30 miles. The problem with lead acid is that whatever AH rating it is, you pretty much need to divide that in half and that's what your usuable AH will be so if you have a 36v17AH SLA pack, you will only get about 8 or 9AH out of it.
 
SLA's are done. LIthium is only $100 more for the same watt hours. Time for everyone to switch to lithium.

Anyway, if you were charging 8 hours and now only charge 3 hours, that means your batteries are probably finished. If you are using a 2 amp charger, that means you were putting 16 AH back into your pack, thus the 8 hours and are now only putting 6 AH back into your pack. 2 *3hrs = 6AH.
 
Hey I Have the SLA ticket. i the local craigs or call locally you will find a better grade of battery and may even get them free for hauling them away.They are used for power emergency back-up on main frame computers. A drawer of series wired 12v 9 amp batteries can protect data or emergency lighting in Health Care or Command Posts etc. where there must be continuous altternating current.
It is amazing to realize the cost of preparedness every sla in these baks is rated Hospital or Medical quality. If youtried to buy them new the price for two would be $80..
So it pays to be on the lookout for APC Type SLA wholesalers and Medical contractors who are not allowed to take them to the trash. I have four together on my 48 volt three phase front hub motor (no one in america even knows about these)
You may have purchased the junky chinese low lead, low acid replacements, that are really rated 4.5 amps but sold as seven amp
Your motor looks like the typical scooter motor, and they never wear out .unless they are over amped up a hill at over 100+ degree day,
The way to gauge your batteries is to separate them back to 12 volts and charge at 2 amps.
If you happen to touch metal to one it will weld instantly.. I learned that at a junk yard battery area,, touch the red to black and if you can't get it away fast enough its Hot

Also I send a picture of a duel pack ,,2 sets of APC SLA's,, taped up and jumped to suit my needs
Your measly 7 ampers would only be capable of a sissy spark
scooter motors have gotten better too.Yours looks old it is maybe 250 watt but can run 3 twelve volt batteries easily ..Your new controller as well... they can take on 3 12 vol 7 amp batteries and increase speed, distance ,and scare you sometimes.. You will never want to pedal again.. is rocks
You have needed to Pay for a controller, throttle, and batteries, already... Why? cause you didnt read the forums Dude
So you got shafted on the batteries, 40 bucks I bet ,you must never over amp them during charge 2 amps only... You have sulfated them. the chemical reaction inside is weak
Solution? Yes use three together it is safe, charge each battery at 12 volt slowly.. Trickle them You may notice the charge light gos on too soon, that means sulfate
I read there are two new battery's jump in one of the older ones to upgrade to 36 volts it also increases the size of your fuel capacity by 33 1/3 or two more miles at 5 miles faster and dont cost anything
 
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