1000W, 48V, 20Amp battery, motor, bike) for < $900

[davidg11]

Hi,

I lot of people who read this forum, like me, are noobs and simply want to know the cheapest, easiest way to create a powerful ebike. So I thought I'd share.

Basically I'm a Electric bike noob, living in the USA, and wanted to buy a bike, battery, and motor for less than $900 that I didn't have to be a professional bike mechanic, electrical engineer, hobbyist, etc to build. I simply want a cheap, powerful, electric bike to ride. This complete setup cost me $879.

I have the bike and the battery, and the motor setup is arriving tomorrow. Here are the links to my setup:

Bike: $130.00 US http://www.walmart.com/ip/26-Hyper-Havoc-MTB-Men-s-Bike-Black/16531397
This bike has an aluminum frame. The front and back dropouts are steel. So I did not need to purchase additional torque arms for the rear dropout.

Motor and Controller: $290.00 US http://www.ebay.com/itm/231132763662?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Rear Wheel motor and controller.

Battery: $459.00 US http://www.ebay.com/itm/48v-20ah-LiFePO4-Battery-BMS-5A-Charger-Electric-Scooter-Ebike-Bicycle-7-8-Weeks-/141141611139?pt=US_Rechargeable_Batteries&hash=item20dcb21283
LifePO4 48V 20A, includes a 5A charger. Looks like a Ping but cheaper and better charger. However, listen to the description. It DOES take 7 weeks to ship. So if you need it quicker than that, this is not the way to go. However it is the CHEAPEST way to go.

Now I'd love advice what to add, if anything. I will most likely purchase a cheap bike computer to figure out my speed. But other than that, I can't think of anything. A big thanks to wesnewell for helping me on my quest!

 

[mlt34]

Generally looks good, but a couple things to note about the battery:

Battery: $459.00 US http://www.ebay.com/itm/48v-20ah-LiFePO4-Battery-BMS-5A-Charger-Electric-Scooter-Ebike-Bicycle-7-8-Weeks-/141141611139?pt=US_Rechargeable_Batteries&hash=item20dcb21283
Looks like a Ping but cheaper and better charger.

1) That's not a better charger than Ping's. It's ok, but worse than Pings.

and 2) the fact that the battery has only two leads is worrying to me. So it charges through its discharge leads? Doesn't sound like a healthy or safe way to charge a lithium pack, even LiFePO4. The BMS should have a dedicated negative pad for charging.

 

[ambroseliao]

I would be surprised if that battery actually had a BMS. It doesn't look like it in the photos. If there is one, you should be able to see the LEDs as the battery balances. How else can you tell when the balancing is done?

 

[mlt34]

I would be surprised if that battery actually had a BMS. It doesn't look like it in the photos. If there is one, you should be able to see the LEDs as the battery balances. How else can you tell when the balancing is done?

Well like all the aluminum case and non-ping heat shrink batteries, they have a simple, cheap BMS without LEDs to indicate balance state.

But the important part is that they at least have a BMS.

If this battery he bought doesn't have a BMS, then I wouldn't be comfortable using it...

 

[mateusleo]

Don't go for any eBay battery seller... always try to buy from sellers that have good reputation on es. I and couple more members have had good experience buying from sun-thing28. Price is good, so is quality... mostly ships by sea, so might take a while

 

[imorton]

From what I can tell, the battery is coming from another "SunThing28" copycat, as it uses the same photos and specs. Other people have taken the time to see the BMS in the pouch LifePo4 packs, and apparently it doesn't have LED's but is still fully functional and provides a good blend of performance, capacity, and value.

I happen to think that he has gotten himself a good selection of parts and a starter bike with a 20Ah LifePo4 pack. Sounds like a good deal for a quick to assemble eBike.

Not everyone has tons of money, tools, or a workshop/machine shop available in order to get started into electric bicycles.

Keep us posted with photos, and performance reviews as you get the kit all put together.

I'm happy for you, IAN.

 

[mlt34]

Most ebay battery sellers are a crapshoot. Maybe they are good, maybe they aren't. Sun-thing28 is one of the few that are known to be good.

The problem with this guy's battery is that it appears to charge through the discharge leads - an unhealthy and potentially dangerous way to do it. It's a cheap solution that went out of style years ago with modern, inexpensive BMS units. Hopefully it doesn't cause him problems down the road. Future noobs to happen upon this thread, just stick with sun-thing28...

 

[imorton]

Maybe you are confused about the battery, but the "sunthing28" LifePo4 battery charges and discharges thru the same leads.

 

[Dauntless]

So you're saying that these identical looking batteries that come with the same charger are possibly not the same battery from the same manufacturer? The biggest difference I can see is the photographic background, which I don't think will affect reliability.

 

[mateusleo]

Maybe you are confused about the battery, but the "sunthing28" LifePo4 battery charges and discharges thru the same leads.

Not my battery, in this picture you can see that there are 2 red wires coming from the battery inside and theres blue/black wires (can't remamber which one is to charge and which one to discharge).

 

[imorton]

Is it possible that your battery is from the 1st generation SunThing28 (since it is duck tape), versus that SunThing28 now sells them with blue shrink and only one discharge/charge lead?

Just taking a guess… IAN

 

[wesnewell]

Redo the power connections and fuse to the controller from the battery pack. I'd add a precharge resistor too to keep the sprk down when connecting the battery to the controller. But this can be done later when the fuse blows or you get tired of the spark when connecting the battery pack.

 

[dnmun]

the BMS on the sun-thing 28 guy pack has a switch on the BMS to turn off the battery so you don't have the spark when you connect to the controller.

 

[mateusleo]

Is it possible that your battery is from the 1st generation SunThing28 (since it is duck tape), versus that SunThing28 now sells them with blue shrink and only one discharge/charge lead?

Just taking a guess… IAN

That's possible, since i noticed it now comes in blue shrink plastic

 

[mountain biker]

omg I was looking at the same bike on Walmart.com....that's funny..im totally new so how did this bike work out for you. I was thinking of uxing the double speed xiogdang motor...350watts 8 to1 first 4 to 1 second gear front hub motor on a 36 volt of some kind.....but that biked looked cool and it only cost like 129 bucks or something....but how did you know it was steel drop outs ....I can't find that info on Walmart.com

 

[2old]

omg I was looking at the same bike on Walmart.com....that's funny..im totally new so how did this bike work out for you. I was thinking of uxing the double speed xiogdang motor...350watts 8 to1 first 4 to 1 second gear front hub motor on a 36 volt of some kind.....but that biked looked cool and it only cost like 129 bucks or something....but how did you know it was steel drop outs ....I can't find that info on Walmart.com

Take a look at the small diameter tubing in the "swingarm"; I'm pretty sure the entire rear end is steel, but if you have a local Walmart, you could determine this yourself.

 

[Voltron]

Having done a few cheap bike builds now....having the derailleur that bolts onto the frame and axle is a giant pain compared to a frame the has a derailleur hanger on the dropout independent of the axle. Also, the smaller 1" headset really limits your choice of an upgrade fork later, most of the decent ones have 1 1/8" headset.

 

[dnmun]

Is it possible that your battery is from the 1st generation SunThing28 (since it is duck tape), versus that SunThing28 now sells them with blue shrink and only one discharge/charge lead?

Just taking a guess… IAN

That's possible, since i noticed it now comes in blue shrink plastic

this is the last sunthing pack on ebay now:
http://www.ebay.com/itm/NEW-48v-20ah-LiFePO4-Battery-5A-Charger-BMS-For-Ebike-Powerful-Sea-8-Weeks-Gift/141296286054?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D27538%26meid%3D81c1bc2b1f754e4d9805d0ee00cc82df%26pid%3D100005%26prg%3D11353%26rk%3D3%26rkt%3D6%26mehot%3Dlo%26sd%3D131344869561&rt=nc

yep that is a sunthing pack. it is no problem to add a second set of wires to the BMS to charge and you can add a switch on that BMS in the circuit current to turn the battery on and off. that guy who did the trashing thread got a 25Ah pack from sunthing and i thought this 20Ah pack was the biggest that sunthing made. that is why i thought that guys pack was not made by sunthing. i think sunthing bought it from a third person and put his own BMS on it.

 

[tomjasz]

What does this mean in his, sun thing, listings? "Sea 8 Weeks Gift" Iget the 8 week ship time but why "gift". That's how it's declared? Does that work?

 

[999zip999]

There a few back door tricks they like to use. Why ?

 

[dnmun]

never look a gift horse in the mouth.

i just wish we had learned more about that 25Ah pack. that was such a waste.