i need more speed - which way do i go?

[dylan]

Hi
I'm a new member to this fantastic ES forum. I love the heaps of intresting information from very helpfull people.
I currently have one of the cheap Chinese 36v electric bicycles. I purchased it as a non-runner on ebay for £40, got a replacement controller from ecrazyman & a set of 3 x 12v 7ah SLA's from an internet battery supplier. Satnav clocks me at around 14 mph on the flat no peadling. I'm not too worried about range as i never go further than 5 miles (that's why i opted for the cheap 7ah SLA'S). However i would like to be able to do 25 - 30 mph on the flat no peadling. So as i see it i have a couple of options:

1. Just add another 12v SLA to give me 48v & hope the ecrazyman controller can handle the extra volts. This would (i hope) give me a little more speed but possible not the gains i would like. Also i would need to charge the additional battery seperatly as i don't have a 48v charger. Ecrazyman thinks i have a Bafang 250w motor in this bike.

2. purchase a new kit from ebay (48v 1000w - no batteries £203 delivered to UK) from http://www.conhismotor.com in China. I have an old non suspension mountain bike i could use or i could purchase a new cheap mountain bike with suspension. Has anyone used this type of kit before? what kind of speed should i expect with a 26" wheel? With 4 x SLA's on a rear rack am i better off going for a front hub motor to balance the bike, or a rear hub motor so all the weight is over the rear tyre?

Selling my current bike would go a long way to funding the new build if that is the best way to go.
I have included a picture of my current bike & the proposed new kit.
Many thanks & I look forward to reading your replies
Best regards to you all
Dylan

 

[spinningmagnets]

If the motor is wound for 36V, then you could up the volts to 48V to get more speed, but only about 1/3 more at best, so 15-MPH at 36V might equal 20-MPH at 48V. More voltage than 48V might overheat the motor.

Using a controller that allows you to feed the motor more amps at max throttle will help accelleration, but creates heaps more heat in both the controller and motor. You can get them very warm on occasion when accellerating or hill-climbing for a few minutes, but like parachuting, you can only do it wrong once.

A bigger motor can swallow more volts and amps without overheating. Look for a motor thats rated for continuous duty providing 25-MPH at 36V, and then feed it 48V, that "should" provide 30-MPH.

 

[Anonymous]

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[philf]

I'm a little leery of "conhismotor.com"... Check out this other thread: http://www.endless-sphere.com/forums/viewtopic.php?f=1&t=12555&p=190147&hilit=conhismotor#p190147

 

[Drunkskunk]

con-his-motor . com? Sounds like an invitation to be Conned.

your bafang could do 20, maybe, under the right conditions and with Lithium 48v batteries, but thats it's upper limit. They are great motors, but small.


Avoid Ebay for motors. there are a couple reputable Ebike sellers out thwere, but most are junk.

if you want 30mph, I would recomend a Nine continents motor and a 48V lithium battery. No idea who sells them in the UK, but Ebikekits.com and Ebikes.ca sell them in the west, and Ping could provide the 48V battery

 

[dogman dan]

Fast costs money, but medium fast is not so bad.

The 9 continents is a good example of a middle to low price motor that's fast enough. Wilderness Energy kits, using the aotema are another. Both can be bought in 48v versions, or have 36v controllers than run 48v sla's no problems. These example should do 25 mph or more at 48v even with sla's. For rides in the 5- 10 mile length, sla's or nicads still work great. Lithium is needed for long ranges, or big voltage packs that get too heavy with lead.

Your current bike is so slow because it's designed to be that way for legal reasons. It's likely to have a motor wound for slow, so the better controller still couldn't pep it up. You need a motor with a lower winding count, like a crystalyte 407, or 406, Aotema, or 9 continents. The controller you have might be ok, even at 48v if it has 63v caps inside. Look inside for little cans with numbers on them, and see if any are less than 60v. If the controller is no good for 48v, get a new one in the motor kit, or another for 48v from ecrazyman. Look for at least 20-30 amps, 48v.

 

[dylan]

Thanks for the info Guys
'Con my motor' is a very suspect company name indeed...!!!
i will email a couple of ebay users that have purchased the kits & let you know their replies
i think i will leave my slow existing bike as it is because upgrading to 48v on it's own is not going to get me the speed i require
i can use the slow bike as it is for now & sell it after my new build to help fund the project

in your experiance am i better off going with front or rear hub motor (with 4 x SLA's on the rear rack)?
also should i use a cheap new mountain bike with suspension or i also have an old non-suspension bike
best regards
Dylan

 

[chet]

conn's web site is a cheap ripoff of Goldenmotor.com. Also check golden motors forum. Get a kit from ebike-kit.com or equivalent UK dealer. Customer service is worth the little extra money. I get 25 mph on flat with 500W and 36V lifepro. I am 210 lbs.

 

[dogman dan]

Ebikes.ca ships worldwide. Quality stuff from canadian dealer.