My 1st ebike

[cosmicman]

This is my 1st ebike, 36v 750 watt rear motor with 3 x 12v 12ah SLA's

I will probably upgrade to the more expensive LiFePo4 batteries a few months down the line, but for now I'm getting 28mph for 15+ miles on the straights with no pedaling and a 2-3 hour charge time so I'm content for the time being.

The rear rack had to be supported with some small welding and 2 extra steel bars, but it worked perfect.

UPDATE
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The bike has now had a respray - some cables were molded into the frame before painting along with the power meter.

 

[dumbass]

This is my 1st ebike, 36v 750 watt rear motor with 3 x 12v 12ah SLA's

I will probably upgrade to the more expensive LiFePo4 batteries a few months down the line, but for now I'm getting 28mph for 15+ miles on the straights with no pedaling and a 2-3 hour charge time so I'm content for the time being.

The rear rack had to be supported with some small welding and 2 extra steel bars, but it worked perfect.

Not to be a kill-joy but remember to let us know how long those small SLA batteries last at that load and charging rate. The max recommended charge rate for a 12ah SLA battery is only 3a and I'm guessing your exceeding that to recharge in 2 -3 hours after a 15 mile ride at 28mph. Do you know how many ah your consuming during those rides? I'll bet those batteries are gasping when they hit the charger and I hope your charging ASAP after your ride and if you keep treating them that way you've already started saving money for your new pack.

 

[Kepler]

Always good to get your first project under your belt. Good first build. Content for the time being. The "time being" might be shorter then you think. This E-bike hobby is very addictive.

I couldn't see any torque arms fitted. Be very careful if this is the case. Most important safety feature (after brakes of course) in my opinion.

 

[morph999]

looks good. I like your battery box. And I'm impressed that your bike goes 28 mph at 36v. That's what my 5303 hub motor does. I didn't think any other other motors went that fast at 36v. Maybe you are a thin guy?

 

[dogman dan]

Could be a 5303. It looks pretty big.

My first bike with sla's I did the same thing, ride full speed till the light on the throttle said the batteries were done. That yellow throttle light is a you just killed your battery light, and should have turned color much sooner. About 50 cycles later I had lost 1/2 the range. But, if it gets you to lithium that much sooner, maybe its a good thing in the long haul.

While the rack looks well built, I'd rethink the thing. You are just adding weight that is not shock cushioned to the rear wheel, and will still have the disadvantages of hard tail in a way. The spokes and rim get pounded, and the battery and electronics shook up. Please don't get the impression I'm ragging on you, I just went through the bent wheels thing on a couple bikes that carried sla's or heavy nicads. But of course, I was beating the crap out of em often off road. If your ride is on good pavement, you'll be fine.

Check out the axxiom seatpost racks. Then you reinforce it to handle 50+ pounds. A broomstick or piece of aluminum pipe up the seatpost to strengthen it, and then a brace from the rack to the bottom of the seatpost mount. Works great, and then the pricy lithium rides on the suspension, and the back wheel doesn't get bent.

 

[cosmicman]

That's a good idea dogman with the battery being off the rear wheel and riding on the suspension instead.

These SLAs just have to last me about 4 months and then I'm ordering a LiFepo4, I will probably get a few steel bars welded on the bottom of the seatpost upto a rack like you meantioned. It seems a great idea. I'd rather wait for the lighter battery, as I wouldn't trust the weight of 3 SLAs hanging from the seatpost + with me sat on it also.

 

[dumbass]

That's a good idea dogman with the battery being off the rear wheel and riding on the suspension instead.

These SLAs just have to last me about 4 months and then I'm ordering a LiFepo4, I will probably get a few steel bars welded on the bottom of the seatpost upto a rack like you meantioned. It seems a great idea. I'd rather wait for the lighter battery, as I wouldn't trust the weight of 3 SLAs hanging from the seatpost + with me sat on it also.

If your interested in Thunder Sky cells (20ah) they are on a great sale right now at Elite Power http://elitepowersolutions.com/products/product_info.php?cPath=16&products_id=74 Only $104 for a PACK OF 4 INDIVIDUAL cells. Great pack at an even greater price. I have 4 of these 12v pack already. But I paid $16 for 2 and $128 for the other 2.