possible dying battery pack?

[ToVo]

Very new to this ebike lark, so please be gentle!

I recently bought a s/hand Ancheer ebike locally [although it has the Myatu logo on it- it's the Ancheer power plus mountain bike. - 36v 8AH bottle battery pack marked 2017

The guy I bought it off had it from new and reckoned it had been used lightly, but fairly regularly. [He was thinking of upgrading and wanted rid] So I've had it for a week or so and am trying to get to grips with it's foibles.

The problem is that although it's fully charged - showing 3 green, once I've ridden it for a couple of minutes- even in low PAS mode, it just dies and all the the lights on the display go out. [the 3 green still light up though]. Reset on the battery on/off and I'm good for a couple more minutes before tha same thing happens again. Given that I live in a very hilly area, this is not good.

Before I start panicking and go out and spend a load more dosh on a new battery I thought I'd ask you good folk here what the possible problems might be:
an intermittent connection fault? a dead/dying cell in the battery pack? an electronic glitch? something else entirely?

Bear in mind that this is my first ebike so I'm still 'testing the waters' as it were and I'm not yet ready to go out and spend a grand or more on something new and shiny.

 

[Nealh]

If it is the battery sounds like cells or some are knackered tbh, might only be a bad cell or two causing a severe voltage drop or current draw to be low.
What you need to do is measure/check the voltage with a meter after it is charged to see if there is a problem, like wise when out on a run also check the voltage when it cuts out. For a couple of quid you can buy a very basic led type two wire small meter to rig up for checking, they give voltage reading, % reading and a capacity bar/indicator.
If the voltage under use doesn't collapse then the controller is likely to be at fault, the only way to know is see what occurs to the voltage by monitoring it .

 

[mike killay]

If it is the battery, do not rush out and buy another one but send your old battery to Inmarsat. They will open and check it, as said above, might be just a faulty cell. In any case it will be cheaper to get the case re-celled.

 

[ToVo]

Inmarsat? the only company I know of called that deals with high end Satellite phones [with prices to match]

 

[mike killay]

Sorry, forget Inmarsat
goto
http://www.bga-reworking.co.uk/

 

[soundwave]

this is his battery web site https://ebikebatteries.co.uk/

 

[ToVo]

Thanks guys. will check out battery when I get my multimeter back off the guy I loaned it to.
I'll report back and see where we go from there. If the battery is ok, then it might be the controller. I note that they are'nt that pricey.

 

[artspeck]

I had a similar problem once and it was the key barrel. I had that replaced and it’s been good ever since.

 

[ToVo]

I had a similar problem once and it was the key barrel. I had that replaced and it’s been good ever since.

cannot think that it is that, since all the key does is lock/unlock the battery into the carrier.

 

[D C]

cannot think that it is that, since all the key does is lock/unlock the battery into the carrier.

Some battery lock keys also switch the battery on, I had one that worked like that but it was a rack battery so probably not applicable to your bottle battery.
Dave.

 

[Nealh]

Most bottle/down tube batteries only have a lock to secure it to the dock cradle, most have a separate on/off switch that switches via the BMS.

 

[Nealh]

I had a pair of batteries that did a similar thing a few years ago, both near full charge and both only working for matter of yards before no power, after checking out the batteries the fault was found to be an issue with the main controller.

 

[ToVo]

Ok. guy who has my multimeter has gone on his hols, so I bought one of those led voltmeter things off the bay, and checked the voltage- 100% ok, and this is after I'd been round the block a couple of times and had a half dozen resets. Plan now is to wire said voltmeter into the battery 'spikes' on the holder so I can monitor what happens on the move. Good idea- or not? Might experience a bit of a voltage drop if I have more than a foot or so of wire, but it should give a decent indication of what's going on.
Gut feeling? it's the controller, but is it an electronics issue or a loose conection somewhere in the system?

 

[Deleted member 25121]

Ok. guy who has my multimeter has gone on his hols, so I bought one of those led voltmeter things off the bay, and checked the voltage- 100% ok, and this is after I'd been round the block a couple of times and had a half dozen resets. Plan now is to wire said voltmeter into the battery 'spikes' on the holder so I can monitor what happens on the move. Good idea- or not? Might experience a bit of a voltage drop if I have more than a foot or so of wire, but it should give a decent indication of what's going on.
Gut feeling? it's the controller, but is it an electronics issue or a loose conection somewhere in the system?

There won't be any voltage drop along the wires going to your voltmeter since it will draw negligible current.
Use it to monitor the signals going into your display as close to the display as you can.

 

[ToVo]

so........... I hardwired the voltage indicator into the battery connections and powered up the system. The battery showed 3 green. The led indicator showed a full battery. The controller gave a full bar of lights.

I selected mid-range and off I went. The controller indicator lights almost immediately dropped to 3 lights, the led showed 100%.

10 seconds later the controller dropped to 2 lights and then switched the motor off and went dark. The led voltmeter showed 100% for a couple more seconds and went dark.

I reset everything and repeated the experiment with exactly the same results.

So, learned gentlemen [and ladies] WTF is going on.

duff Controller?

iffy Battery?

Both?

 

[Deleted member 25121]

That shows that the battery is probably OK and the problem could be with the display (ie the thing you call the controller), the controller (with the power electronics which I think is the box on your down tube) or the wiring / connections.

 

[ToVo]

so it looks like I'll be replacing the controller. There's a lot to choose from out there, but since this is a cheapo bike, I'm not minded to splash out for a top end bit of kit. On the other hand I don't want to replace my crapped out controller with another cheap'n nasty one.

so recommendations please for something compatible that will do the job without my spending more than the bike's worth.

Ancheer bike - 36v/8.6A/ battery ; 250 W motor

 

[Nealh]

Show us a pic of the controller with label and the connectors.

 

[ToVo]

Show us a pic of the controller with label and the connectors.

will do when I get back home later in the week.

 

[ToVo]

there you go. looks like a generic cheapo controller
the usual jumble of cables