Help! Stealth bomber dead!

[OlliAllen]

Hi,
I have a 12,000w stealth bomber bike (Chinese copy) that worked great when I bought it (used) about a week ago

However I went out on it yesterday and it got down to about 3 bars of battery and then when I applied full throttle it died at around 45mph. However if I do not apply full throttle it will work great.

The screen completely turns off and all the buttons stop working. If you try to turn the bike back on it does not turn on until you take off the side panel, disconnect and reconnect the battery. It will then turn on and the problem repeats.

Any advice would be greatly appreciated
Thanks in advance
Olli

 

[matthewslack]

Hi,
I have a 12,000w stealth bomber bike (Chinese copy) that worked great when I bought it (used) about a week ago

However I went out on it yesterday and it got down to about 3 bars of battery and then when I applied full throttle it died at around 45mph. However if I do not apply full throttle it will work great.

The screen completely turns off and all the buttons stop working. If you try to turn the bike back on it does not turn on until you take off the side panel, disconnect and reconnect the battery. It will then turn on and the problem repeats.

Any advice would be greatly appreciated
Thanks in advance
Olli

12kW? Is that manufacturer's exaggeration, or an accidental extra 0?

Almost certainly the battery cannot cope with high current demands of the motor. If you provide details of motor and battery, including pics of any labels or markings, analysis can go from there.

 

[OlliAllen]

12kW? Is that manufacturer's exaggeration, or an accidental extra 0?

Almost certainly the battery cannot cope with high current demands of the motor. If you provide details of motor and battery, including pics of any labels or markings, analysis can go from there.

Yes, 12Kw

Reaches up to about 90-100mph (when I had it working)

I’ve attached a photo of the bike for reference

The battery is (with label on the side of it) 72V Panasonic 40AH, which matches the 72V 12kw motor

Thank you again for your help it really is appreciated

 

[soundwave]

it is called voltage sag ie when you use the throttle the batt cant cope with the load anymore and goes below the voltage that the motor needs and thus shuts down.

simple answer is you need a new batt with decent cells in the first place and at that size wont be cheap.

eBike Batteries

ebikebatteries.co.uk

id say your looking at around £1000 for a custom batt to be built.

 

[OlliAllen]

it is called voltage sag ie when you use the throttle the batt cant cope with the load anymore and goes below the voltage that the motor needs and thus shuts down.

simple answer is you need a new batt with decent cells in the first place and at that size wont be cheap.

eBike Batteries

ebikebatteries.co.uk

id say your looking at around £1000 for a custom batt to be built.

Thanks for the advice
Would it be possible to re-cell the battery instead of completely replacing it?

 

[soundwave]

all the cells will need to be replaced in the case/bms what you have just cells atm are not cheap there around £10 each.

 

[wheeliepete]

The battery is (with label on the side of it) 72V Panasonic 40AH, which matches the 72V 12kw motor

The battery needs to mach the controller max. amperage output, not the motor. What controller are you running?

 

[soundwave]

i think it is one of these.

Stealth bomber 12000w 72v 150A dirt E-bike 2021 | eBay

Stealth ebomber 12kw electric bike. Used as a test bike. Less than 60 miles 2 battery cycles. A serious machine. It will want to flip you off the back before you know what's happened. Kick stand.

www.ebay.co.uk

 

[wheeliepete]

i think it is one of these.

Stealth bomber 12000w 72v 150A dirt E-bike 2021 | eBay

Stealth ebomber 12kw electric bike. Used as a test bike. Less than 60 miles 2 battery cycles. A serious machine. It will want to flip you off the back before you know what's happened. Kick stand.

www.ebay.co.uk

I think you're right SW, it's running a 150 amp Sabvoton controller. Seller emailed me a photo of the battery pack, it's huge, looks like 20P20S, but can't say which cells, so likely 2000mah Chinese jobs. Running at 7.5 amps on full chuff, they are not gonna last well. If the OP turns the controller down a bit, it would help, but the damage may already be done. A nice pack of 10P20S Samsung 21700 40T's would get it flying again, but a cool £1800 for the cells from Fogstar.

 

[soundwave]

yeah those batts are massive and expensive but id not trust it even turned down as not like you can remove it fast and all it takes is for 1 cell to pop and the hole lot will explode.

 

[wheeliepete]

Just hope your on the canal tow path if the worse happens.

 

[soundwave]

i have never seen a bosch batt catch fire lol but dont go down the cannel much these days as rammed with ppl since they paved it pita.

 

[sjpt]

i think it is one of these.

Stealth bomber 12000w 72v 150A dirt E-bike 2021 | eBay

Stealth ebomber 12kw electric bike. Used as a test bike. Less than 60 miles 2 battery cycles. A serious machine. It will want to flip you off the back before you know what's happened. Kick stand.

www.ebay.co.uk

Looks quite like the on in https://www.pedelecs.co.uk/forum/threads/e-bike-terrorist.42844/
though the handlebar grips are a different colour.

Hunt for e-bike rider who's been 'terrorising' prom walkers in Rhos-on-Sea

Police seized the bike after the owner fell off and fled while officers gave chase

www.dailypost.co.uk

 

[soundwave]

yeah id not crush that with the batt inside it pmsl

it does not look like it crashed tho, prob ran out of batt and had to dump it

 

[Nealh]

12kw is a motorbike one has to expect motorbike prices for a proper battery one would want one at least 225a rating if not more to lessen voltage sag.

 

[Nealh]

200 x 40T's is £821 via Foggy,

 

[wheeliepete]

200 x 40T's is £821 via Foggy,

That's better!! I was looking on the wrong part of the website.

 

[Nealh]

That's better!! I was looking on the wrong part of the website.

However you are pretty much correct I expect with the cost of a battery pack for said motorbike, a commercial 20s pack with pucker cells is going to be the thick end of 2k.

 

[wheeliepete]

However you are pretty much correct I expect with the cost of a battery pack for said motorbike, a commercial 20s pack with pucker cells is going to be the thick end of 2k.

Agreed, I think Jimmy would charge that kind of price at least.

 

[Nealh]

So few people have any idea of the cost of lion cells and batteries for high performance/high current draw usage.