First post so be gentle

[YamaRDLC]

If this is in the wrong part of the forum please feel free to move it

I have a question about a bike i just bought off ebay, its a Carrera Vengeance E Spec mountain bike.
It is in very good condition overall but was advertised as having a dead battery and no key to remove it but does have a charger.
Got it for a cheeky bid of £175 and it was fairly local.
Got a key from replacementkeys.co.uk, highly recommended, got it the next day and only about £9
Even with the key the battery did not like coming out but got there in the end.
Watched a few youtube videos on how to check your battery and measured the voltage at just 2.26v so assumed it was unrecoverable, the charger would not charge it at all.
Took the battery cover off and connected my bench power supply, gave it 42v at 0.9a and it gradually started to charge and after 4 hours it reached 36v and i then plugged in the charger which then worked and took another 5 hours to fully charge the battery.
Measured it at 41.9v last night and it was still 41.7v this morning, what should a healthy battery measure?
Haven't reinstalled it yet as i wanted to measure it a few times.
Before i did this and assuming the battery was dead i made another cheeky bid on ebay and got another battery on the way for £60 which the seller claims is in good condition.
Cant believe the cost of new batteries or some second hand ones which can be 300 - 400 so more than the bike is worth, hopefully i will be able to recover this second battery as well.
The bike has been fitted with a throttle which i don't understand, bearing in mind i have not connected the battery back up can some one explain how this works as i thought these bikes were supposed to be pedal assist so does that not work now?
Never had an E bike before so assume i know nothing

 

[matthewslack]

Those fully charged voltages are fine, and the battery didn't catch fire, so balance may also be fine. Worth checking since you have opened it up, if you can get access to the cell group balance wires or connector.

The risk of the first part of your recovery charge is that the BMS is not doing balancing, and if cell groups are out of balance, one or more get pushed to a voltage where they fail in a fiery way. But nothing bad happened so you got away with it!

The battery has 10 cell groups, and each should measure 1/10 of the full voltage, to within a few hundreds of a volt. Verify that if you can.

If that is all in order, then the next test is to ride the bike. Sitting flat longterm can seriously affect capacity and so range. But if it works, it works.

It would be interesting to hear what happens next!

 

[YamaRDLC]

What about the throttle? how does this work and does it affect the pedal assist?
I did the first part of the charge with my bench power supply in the middle of the garden because i was wary of a battery fire.

 

[matthewslack]

I didn't know a Carrera Vengeance had a throttle!

The UK rules on throttles for EAPC ebikes allow throttle alone from a standing start to 6km/h without pedalling. Above that speed throttle is only allowed to be active if rider is pedalling, but can propel you to the full 25km/h.

Throttle only to 25km/h is allowed if you put the bike through SVA (DVLA single vehicle approval).

 

[YamaRDLC]

The bike was modded i guess, i just wondered if this removes the pedal assist.
I guess i will re attach the battery and try it.

 

[Nealh]

41.5v - 42v is that which one should see for a fully charged 36v lion battery.

 

[saneagle]

The bike was modded i guess, i just wondered if this removes the pedal assist.
I guess i will re attach the battery and try it.

Does the bike have an LCD? If it does, please show a photo. I'm pretty sure that the Vengeance E never had a throttle. Is your a normal vengeance with a kit added? Please show some photos of what's on the handlebars, the area around the bottom bracket where the sensor is and the motor.

 

[YamaRDLC]

 

[saneagle]

View attachment 63315View attachment 63316View attachment 63317

That's the original Suntour HESC system AFAICS. I've never seen a throttle on one before. There's no connection for one. I'd be interested to know how it's been done. The controller needs two signals to give power. The torque sensor arrangement gives a pulsing pedal rotation signal and a 0-5v analogue signal for how how hard the pedal is pressed. A normal throttle gives a 1v to 4v analogue signal, which would work as long as you were able to spoof the pedal speed signal. I posted about how to do that a month or so ago.