Upgraded my Bolt Pro to 48 volts and I cant find anyone that has these problems and now the 48v battery cuts off with nearly a full charge.

[djwikkid]

Hello everyone and thanks for any help or advise you can give me to help solve what's going on. Here's the full rundown in detail....

I bought a Jetson Bolt Pro in summer of 2020 and absolutely loved it and still do in many aspects. Outside of having to buy way too many innertubes this bike has been nearly problem free and a joy to own. At the end of October I saw on Amazon a 48v and what they claimed to be 30000aH battery. I knew that was BS right away, but I ordered it anyways for the price of $86 shipping included. When I put 48 volts into my bike it was a whole new bike once again and the added acceleration was almost too fast. One problem though with the 48v, from a dead stop I had to baby the throttle until it got to about 8 MPH or the motor would stop accelerating and sound like a dull grinding sound. Once I let off the throttle this too stopped. Someone said that the hall sensor was bad, but I didn't fix or find the problem then. I kept on riding and got used to using the bottom half of the throttle gently until I got past that point and could turn the throttle to max. At first I could ride around 6 miles before it cut off. I think that the BMS is what's killing the power, but when I switched to the 36 volt battery and before it could get back up to speed, it too would cut off. But on the 36 volt I just had to turn the key off and back on to get power back to the motor. The 48v would require me to stop and unplug the battery and reconnect to get power flowing from that pack. So fast fwd to today and the 48v pack ran as long as I babied it, but once I went to full throttle, it cutoff with 50.4 volts showing on the voltmeter so I pulled over to swap connections back to the 36v pack, just like before the 36v pack would cut off being this was it's first use of this battery today. I cycled the keyswitch and ran it super gentle and that 36v pack would slowly come back to normal. I've been into ebikes for a few years now so I have several hunches. Maybe the battery is to blame since it was one of those over stated Chinese take out.​

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My hunches say one of the hall sensors, a break in one of the motor cables or a very not funny way God is causing this to happen and having a time with it. I welcome all suggestions, advise and criticism's.​

What I need is what is happening to the bike when that plastic grinding sound is happening on the ramp up way and why is the 48v pack cutting off so soon. I did open it up and make sure the cells are in balance and they were. So I'm stumped.​

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I appreciate any and all info sent.​

Sincerely​

Dan W​

 

[Tom@WashDC]

Send us a link to the battery you purchased?

 

[Slaphappygamer]

Assuming the original battery is 36v. The new battery is 48v. Your controller is probably rated for 36v, which may have an "overcharge limit" of 42v. It's likely that you are hitting "overcharge limit" when the 48v battery is in. The 48v battery will be at around 54v when fully charged. To successfully use the 48v battery, you'd have to discharge it to about 42v. That will be on the cusp of a "low voltage cutoff" alarm and is unhealthy to maintain. The "cheap" fix would be to get a 48v controller and display combo. Then you'll just need to rewire your bike.

 

[keithj69]

"I knew that was BS right away, but I ordered it anyways for the price of $86 shipping included"

How many ebikes did you have before this one? What is your understanding of batteries/voltages/watts and controllers?

 

[Tom@WashDC]

...At the end of October I saw on Amazon a 48v and what they claimed to be 30000aH battery. I knew that was BS right away, but I ordered it anyways for the price of $86...

That line above is the very definition of Cognitive Dissonance!

It sounds like the bike gave you a few good years of use, and now you want a bike with more power. More power necessitates better wheels, tires, frame, motor, brakes, etc. than the Bolt Pro has to offer. The bogus battery that you purchased equals 21% of what that bike cost new, and you have problems. Do not throw good money after bad.

You like riding ebikes? You want more speed? Cut your losses, don't spend any money fixing it, and very little time. Assuming you have the funds, I recommend you step up and get a bike that will give you better performance/speed.

 

[harryS]

The Jetson Bolt Pro is supposed to have pedal assist. How did it work on pedal assist with either battery?

My first response is weak battery. Bike runs when you feed it power slowly. Hit the throttle for a burst of current and it shuts down. That's usually weak cells that sag in voltage and shut off either the battery or the controller. Easy to believe the cheapo 48V battery has weak cells. With the same thing happening on the 36V pack, I would say maybe that battery is worn out too.

The complaint about motor noises is what does';t fit. On my ebikes that crapped out, I've only heard motor growling and funny sounds when the controller was dying. I've had two go bad kike that after they had taken in water.. So you could have a controller issue. MAybe it was aggravated by overvolting, Some 36V only controllers only have 50V compinents inside, and they will fail over time.

So how much you want to spend? Obviously, it would be nice to not toss away the bike, but you'll have to buy a new controller from Jetson, or retrofit to a third party controller/display. Either will cost around $100. And then you could replace the controller to find out one or both batteries are worn out too,