Battery Upgrade on Detroit Bikes E-Sparrow

mjk1217

New Member
Hello,
I am considering purchasing an additional battery for my Detroit Bikes E-Sparrow to extend my rides. I attached a photo of the controller specs. The battery i have now is a 36v 7.8 AH, the motor is a 250w type. I would like to purchase a battery that would give me a bit longer range (possibly 13 AH). This battery is a 4-Pin style and it has been a bit difficult to find. Detroit Bikes actually has the original battery I was just looking at something that's a little better, providing a bit more range. Any thoughts on using a larger AH battery with this configuration ? Given the specs on the controller maybe I cannot use a battery with a 13 ? I am just getting into e-bikes so I appreciate any feedback.
 

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harryS

Well-Known Member
From the picture, looks like a Hailong style battery. Must be a small bike. That battery looks huge on it!

Yes, you can install a 36V battery with a higher AH rating. You could find a 36V15AH and double the range.

The kicker is there are several styles. As in this photo. You probably have the one at the top, but that comes with either 4 pins or 5 pins, and sometimes the pins are round vs flat. And I believe there there some slight differences in the cradles too. So good luck,
hailongz.jpg

 

mjk1217

New Member
I really like the bike, it’s light and, despite the big battery, it’s a great looking bike. Range isn’t bad I’d just like to go a bit further. It’s a 4 pin and I’ve noticed the different styles in the cradle. Likely, I’ll just get another battery from Detroit bikes. Thank you for your feedback.
 

harryS

Well-Known Member
Probably safest move, if they're not asking $600. A 7.8Ah battery must be 75% air inside that case.
 

mjk1217

New Member
I believe they have batteries for a bit more than $200. Got a question about controllers. On my bike, the battery controller is in the cradle. Is that the same for the cradles in the pics you sent ? Just thinking if I bought the larger battery, maybe I mount the new on the frame and put the old on a rack. Not sure what connectors/adapters are needed if I wanted to share each battery independently.
 

harryS

Well-Known Member
They can and do put the controller in the battery cradle on some Hailongs, specifically the cradles at the top of the picture. But a new battery will still fit and use the controller.

There are some problems with your idea of alternating two batteries, if the original battery has the controller is in the base, First the wiring is in the base, so you have to go in there. If you do a hard Y-connection to the alternate battery, the first battery has to come out before connecting the second, and vice versa because they will be at different voltages. You can get around this with switches, but if you flip them wrong, you could connect a depleted battery to a fully charged one. They do sell smart y-connectors for this purpose, but life would be simpler if you find a bigger 13Ah battery that fits.

With a bigger battery, you'll use the small one for short rides and the big one for the log rides.

Or you could buy a bigger battery, and if it doesn't fit, you move the controller to the new battery cradle. Put that on your bike, and sell the little pack to another Sparrow owner.