Cheap E-bike conversion

[senoritoriver]

Before i get started here are my parameters:
speed: 15-20mph (without pedaling)
Type: front wheel drive hub motor
distance: 20miles
Hills: downhill for the first 10mi and uphill for the last 10mi
My weight: 150lbs
Budget: $600
Legal constraints: 750watt max (but i'll risk 1000watt)
My bike: Trek 3500, disc brakes, 19.5" frame, 26" wheels
Ability: basic but have access to help from an electrical engineer

I want this to be part of my summer work out, but the biking trips would be just too much for me without some help. i can do solely pedaling for the first 10 miles, but the 10 miles of uphill coming home are fairly tough. I saw the cheap Chinese 48v1000w kits on ebay for $270 but i would also need a 48 volt battery with probably atleast 10ah. plus im not sure how reliable those cheap chinese kits are. I really only need it to be assisting, not completely taking the load. so hopefully the cost can be reduced somewhat. and i'm completely open to building mounts for SLA batteries. Let me know what kits, batteries, and chargers you would buy. Thanks!

 

[wesnewell]

Almost all kits come from china. And if they don't, your budget wouldn't come close to them. And don't even consider sla batteries unless you can get them free. I wouldn't even use them for free, but I'm not on a budget either. I built 3 bikes using kits from yescomusa.com (ordered off ebay because they're cheaper heir than form their website.) and they're all still going after more than a year and probably >8k miles total. I've got about 4k miles on my 48v 1000W motor without a problem. $600 would cover cost of kit and lipo battery pack easily.
http://www.ebay.com/itm/48V1000W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/390406595360
http://www.ebay.com/itm/48V-500W-E-BIKE-ENGINE-CYCLING-REAR-MOTOR-BICYCLE-KIT-/300575755917

 

[amberwolf]

Is the legal limit 750W delivered to the road, or pulled from the battery? Will result in very different performance.

Skip the SLA, especially since you need it for hill climbing--with SLA you're hauling a lot of dead weight for little performance.

 

[dogman dan]

Simple requirements for most kits, assuming this hill isn't a vertical wall. The disk brake requirement eliminates some kits in front hub though. Got posts on your front fork so you could use V brakes on the front? Or a fork you could swap in the garage?

The 600 buck budget just covers the battery though, unfortunately. You could sla, but 10 miles is pushing the range for an sla setup. There are cheaper currie motor kits, but peeeyeeew. Noisy suckers.

If you told us what continent you are on in another thread, I forgot it. We really can't recomend vendors ouside of china till we know if you are in australia or austria. Talking in miles makes me assume USA though.

Yes com usa has good kits cheap that ship from a usa address. Under a different name, you see those kits on ebay. Look for ships from City of Industry CA.

Emissions Free shipping from China is another good value. The muxus direct drive kit for lowest cost 750w.

 

[senoritoriver]

the limit is 750watt to the road. so heres my list of parts:
Trek bike (may have to get the disk brakes changed out)
48v1000w rear wheel ebike kit
4x 5ah 22.2v lipo packs from hobbyking
premade series and parallel connections
tips for the controller to make it match the pack
a 6s charger/balancer
and a meanwell power supply.

any suggestions on the charger and power supply?

 

[wesnewell]

Standard LVC for 48V controllers is 42V. That's about as good as it gets for using a 12s lipo pack. The controller LVC will cut in when you get to 5-10% charge left. As for charger and psu, anything will work. Hyperion 1420i and 24V 25A psu would charge a 12s 10ah pack in ~30 minutes at max 20A charge rate. Or you could use a cheap 50W 6s charger and take about 8 hours to charge from empty. Either will work fine. Just depends on how fast you want to balance charge, and how much money you want to spend. A 6s imax ac/dc charger can be had for about $30 shipped if you don't need a fast charge.

 

[snellemin]

I'm with Wesnewell. That Ebay kit with lipo and cheapo charger will be around 600.

 

[senoritoriver]

i found an iMax B6 on amazon that can take AC power supply. Its only $28 plus a $7 12volt 5 amp cord. I'll be charging over night most likely so it's no problem if it takes a while. that may even put me below $600 if shipping from hobbyking isn't too much. i hope the starting project works. if it does i'll start putting more money into battery packs and chargers when i save up more.

 

[Pure]

RC LiPo is not a battery that you should be comfortable with setting it to charge and then going to bed. You don't have to physically watch it but you should not be sleeping.

If you plan to "set it, and forget it" then you need to be looking at LiFePo4 or other "safe" batteries. This will blow your budget tho.

 

[neptronix]

Yeah RC lipo is going to require some research and care to deal with. It is cheap but the equipment to balance it is not. It makes financial sense when you want the lowest weight and highest power per dollar. But it is the most dangerous of them all.

I started out with a $150 cell_man MXUS kit and 10AH/10S of lipo. It did 18mph, was pretty light, and i thought it rocked at the time.. Put about $700 into the build and had a >20 mile range. I can't help but think of why i can buy all this stuff at retail cost and my finished product still costs 1/2 of what a commercial unit would.

Eventually i graduated up to the MAC motors, which are rather powerful and torquey for their weight. The MXUS kit definitely got me into the door of the eBike world though and started the addiction

Forget the iMax. It is not a quality piece, lots of them have blown. Lots of them have been innacurate. Just like all of the cheap chargers.. Start with an iCharger 1010b+ or hyperion 1420i. It can charge your full pack without you having to constantly swap connections etc. Trust me when i say that eventually leads to a mistake.. It is also cool to charge your entire pack with one plug and no hassles when doing bulk charging

http://www.hobbyking.com/hobbyking/store/__6609__iCharger_1010B_300W_10s_Balance_Charger.html

The iCharger 1010b+ is a quality piece of equipment that comes well calibrated, chock full of features, and can last quite a long time. It does 10s.

http://www.amazon.com/Hyperion-EOS-1420i-Net3-Charger/dp/B004E7MQ3Y

For a bit more $, you can pick up this bad boy and run 10s now, 14s later. This puts out almost double the power.


You will not regret spending more $ on a charger down the line. One that prevents you from doing dumb things, tells you what's going on, and doesn't overcharge/undercharge your cells etc.

 

[motomech]

I'm a Lipo noob, and started with the Hyperion 1420i and it's awsome :lol:

I know enough now to know that if I had started off with a cheapo charger, that I would have been doing a lot of head banging.

I'm lucky that I started with Lipo at the same time the Hyperion come out and that I took the advice of guys like Neptronix and skipped over the junk saving me $$$ in the long run, and headaches.

One thing about Lipo though, figure on budgeting 25% of what you spend on the bricks on connectors, wires, tape, padding, etc. It adds up.
It's been somewhat time consuming, but I like it. Right now I'm happy sitting and watching the charger charge, but I'm easily amused

If you are unsure about Lipo in the slightest and don't mind waiting a while, think about Li-on from BMS Battery. They have some larger packs on sale.

 

[amberwolf]

The irony of RC chargers is that the cheap ones that can only charge a decent pack over several hours (minimum) cannot be trusted to do so unattended. Only a few of the more expensive ones *might* be trusted to do that, but they usually can charge at much higher rates and thus do not *have* to be trusted to do it.

Though personally I haven't had any dramatic failures (yet), I still wouldn't recommend charging RC LiPo unattended, regardless of charger, unless you have a fireproof room or container to do so in, preferably outside away from any habitations. Even if the charger operates perfectly, if you have a bad cell (which are not rare by any means), it is easily possible to end up with a fire during charging, for various reasons.

While it is unlikely that you would have such a fire, it is not impossible, and it would suck to wake up in the middle of it engulfing your home.

 

[wesnewell]

I don't think I've ever seen or heard of a fire caused by properly charging lipo. I've seen plenty of ires from lipo that were started on purpose, and some that wouldn't burn even when trying to get them to. Lipo is all I use and I wouldn't change to lifepo4 for anything. It's just too restrictive for me.

 

[senoritoriver]

I hadnt thought about the fire issue... plus that 30 minute charge time from the hyperion EOS 1420i NET3 charger is quite appealing. is there are decently cheap power supply on the market that can put out the power the hyperion is capable of? haha

 

[Pure]

Most use Meanwell or Meanwell clones. You can find them on ebay.

 

[snellemin]

If you don't mind tinkering a bit, you can get two HP server power supplies and hook them up in series for a solid 26V@47A. Those PSU can be found for 20 bucks shipped on Ebay.

 

[wesnewell]

Well, I lucked out and got a used 24V 25A PSU off ebay for $21 shipped. You can use old PC PSU's tied together too as mentioned above. Just a little more hassle to set up.

 

[senoritoriver]

http://www.ebay.com/itm/24V-25A-600W-Power-Supply-110V-Input-Mega-Power-Hyperion-Charger-imax-icharger-/160773080055?pt=Radio_Control_Parts_Accessories&hash=item256ed283f7
any thoughts on this power supply? i like have a 110VAC input since thats the most common plug. i wouldnt have to find a 220VAC if i had to charge in town

 

[wesnewell]

Same one 5 bucks cheaper.
http://www.ebay.com/itm/24V-25A-600W-Power-Supply-Mega-Power-Hyperion-Charger-imax-icharger-/160724102290
It has the right specs.