January 28, 20206 yr Hello is there any one that had a problem with his ebike... The issue is that my ebike goes off sometimes when i use it... When i turned it on it shows all that power are full while i move on the power assist looks like goes down gradually as far as i pedal when i stop pedaling the power assist comes full again..thanks in advance
January 28, 20206 yr More details needed like battery age, cells make/type and controller ampage. What you describe could be an ageing battery that can't handle the load demand asked of it, typically know as voltage sag. Sag is a result of cells with high IR (internal resistance/capacity loss ) due to ageing or abuse to due to too high a load asked of the cells according to the spec sheet. With a ageing /tired battery it shows a full charge and often high/normal voltage for it nominal value, when a load is applied the drops suddenly to cause a cut out. Once the load is removed the voltage has time to recover and after a few seconds it bounces back to quite full again, this is until a load is applied again and the cycle begins over again. Edited January 28, 20206 yr by Nealh
January 28, 20206 yr Author You need to say what type of bike, in particular what type of controller. Hello its roodog chic e bike. Its a 250watt rear wheel hub brushless motor. The battery is a 36 volt 10Ah, lithium-ion.
January 28, 20206 yr Author The battery has 2 years abd and 5 months.. Not sure about what type of controller.
January 28, 20206 yr What assist level do you riding in and under what circumstances does the battery/bike cut out ?
January 28, 20206 yr Author I put the third level even if its in the first level it cuts out.. When i turn the throttle also it cuts out. So no light in the display i have to turn the key so as to start again
January 28, 20206 yr Battery needs replacing, but to be sure connect a volt meter to the two wires between battery and controller. Lift the wheel off the ground and use the PAS/throttle and watch the voltage if it collapses then the battery is scrap.
January 28, 20206 yr Author Battery needs replacing, but to be sure connect a volt meter to the two wires between battery and controller. Lift the wheel off the ground and use the PAS/throttle and watch the voltage if it collapses then the battery is scrap. I tried the voltmeter is not accurate it shows 1 and when i hold the bike up turning the throttle nothing changes. It shows 1
January 28, 20206 yr I tried the voltmeter is not accurate it shows 1 and when i hold the bike up turning the throttle nothing changes. It shows 1 You likely haven't set the volt meter up correctly as it should at least show the battery voltage before you do anything, it should read between 32v and 42v depending on the SOC (State of charge). The dial should be set to DC range or V and on the 200v setting and not AC range or A.
January 29, 20206 yr Author Hello i have bought another voltmeter and it shows 39.4 v when i hold it up and turn the throttle it shows 39.9 v
January 29, 20206 yr Hello i have bought another voltmeter and it shows 39.4 v when i hold it up and turn the throttle it shows 39.9 v Ok now you need to create some load and demand the battery to output some power, so whilst using the throttle gently use the brake so that the wheel still turns. This will draw higher amps from the controller which will demand the battery to work harder, see what the voltage does.
January 29, 20206 yr I tried the voltmeter is not accurate it shows 1 and when i hold the bike up turning the throttle nothing changes. It shows 1 Probably just needs a new 9v battery.
January 29, 20206 yr Author Hello putting load means that i have to sit on it or put weight amd hold it up??
January 29, 20206 yr Hello putting load means that i have to sit on it or put weight amd hold it up?? No, whilst you hold the wheel off the ground and turn the throttle get someone to apply the break gently to put pressure on the wheel without stopping it turning.
January 29, 20206 yr Hello putting load means that i have to sit on it or put weight amd hold it up?? The load required is theoretical power load by means of amps drawn and not a physical weight load. Putting a load on means making the electrical system work harder, the battery is the power source (the weak link), the controller is what provides the load by means of powering the hub. By gently applying the brake it will make the wheel harder to turn, the controller will try and draw more watts from the battery to supply the amp load. If the battery is at fault the voltage will sag/collapse dramatically causing a cut out. Edited January 29, 20206 yr by Nealh
January 29, 20206 yr Author Yes that's what i tried.. I hold it up and drop it down to touch the floor while i turn the throttle.. I can see that voltage get down to 34, 35 v and it collapses
January 29, 20206 yr Right your battery has had it then, the cells will have high to very high internal resistance which is assign of ageing and is detrimental to cell capacity. It is time to send the battery to a recycling centre or possibly use them for a torch.
January 29, 20206 yr Can't repair de battery?? Putting other new cells yes if you have a spot welder and nickle/copper strips.
January 29, 20206 yr Author yes if you have a spot welder and nickle/copper strips. And what kind of batteries i have to purchase?
January 29, 20206 yr It's not economical on an old failing battery. A good capable spot welder is about £130 and then needs a £40 or £50 lipo battery to power it, add on the price of cells about £3 - £5 each, nickle strip and a few other bits . The cost starts mounting up to that of a new battery or simply send it off to ebikebatteries .co.uk to be re-celled for about £300.
January 29, 20206 yr Can't repair de battery?? Putting other new cells Only viable if it was quite a new battery, then as above you need the knowledge and capable equipment to carry out a good lasting repair.
January 29, 20206 yr And what kind of batteries i have to purchase? https://bga-reworking.co.uk/product/have-one-to-sell-sell-it-yourself-2-x-samsung-inr-18650-30q-3000mah-20a/ they can recell the batt for you
January 29, 20206 yr The battery has 2 years abd and 5 months.. Not sure about what type of controller. How have you looked after/charged the battery ? Do you charge to full all the time and let it sit all the time at 42v?
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