Help! E-Plus Mantra Electrical Issue - Help Please !

[chris301up]

Hi guys. I have owned a E-Plus Mantra electric bike for just under twelve months. I purchased this , second hand, as a replacement for my electric mountain bike which was getting a little heavy for me. This is not the best bike in the world but it suits my needs for the moment. I had need to use it yesterday after being stored in the shed for a few weeks. I fully charged the battery prior to use, but during the first mile or so the displayer, first of all went dim, then down to one light and finally went off. I switched the battery off and on and all was well for a short time and then the same happened again. This continued to happen during my return journey home.

I have just had a quick look at this and notice whilst the bike is stationary the displayer unit dims every few seconds or so and finally returns to full brightness. This continues to happen whilst the power is on. I have taken it for a brief spin around the block and the displayer goes straight from all lights showing to just one. Before I investigate further I just wondered if anyone has had similar issues and may point me in the right direction? Cheers guys.

 

[cyclebuddy]

...after being stored in the shed for a few weeks.

Perhaps damp in the electrics? As a first step, I would take the bike into the house for a day or two and let it dry out thoroughly. Beyond that, check the ability of your battery to hold a decent charge: An aging one can appear to be fit as a fiddle, die as soon as you need to draw power, and recover when rested again.

 

[Nealh]

Damp may be an issue a shed is not the best place to keep ebikes unless insulated.

I would first look at the battery take some readings before charging during and after, check out the charger to insure it is also outputting the correct voltage of 29.4v.

For 24v one should see 29.4v when fully charged , if it falls way short then there is an imbalance within .

 

[chris301up]

Perhaps damp in the electrics? As a first step, I would take the bike into the house for a day or two and let it dry out thoroughly. Beyond that, check the ability of your battery to hold a decent charge: An aging one can appear to be fit as a fiddle, die as soon as you need to draw power, and recover when rested again.

Unfortunately, I do not have room in the house for the bike. The only thing I was thinking of doing was perhaps using an hairdryer to see if I can dry it out a bit? Just a thought of course.

 

[chris301up]

Damp may be an issue a shed is not the best place to keep ebikes unless insulated.

I would first look at the battery take some readings before charging during and after, check out the charger to insure it is also outputting the correct voltage of 29.4v.

For 24v one should see 29.4v when fully charged , if it falls way short then there is an imbalance within .

The battery is fully charged and, using a multimeter the battery reads a steady 27.2 volts. Don't know if this helps?

 

[Nealh]

If damp is suspected, highly likely with a metal bike in shed try covering the bike with old duvet or a sleeping bag. Ideally the battery needs storing inside somewhere or a nice dry place out of the damp.

 

[Nealh]

Some displays if lcd and have clock have an internal watch battery, just worth a mention.

 

[chris301up]

Some displays if lcd and have clock have an internal watch battery, just worth a mention.

Display is nothing special. Take a look at image. Maybe I've described it incorrectly?

 

[Nealh]

An led 3 spd no back up battery there then, so looks likely the issue is with the main battery or if damp is affecting the led's pcb .

 

[chris301up]

An led 3 spd no back up battery there then, so looks likely the issue is with the main battery or if damp is affecting the led's pcb .

Could well be? I've just pulled the battery from the bike and put it in the house to warm it through and remove any residual damp present. I'll run the hair dryer over the LED display a little later and also check the output from the battery as also advised.

 

[chris301up]

I've just been taking a quick look at the battery and it as connector with five integral terminals that slide onto corresponding pins. I'm assuming these could be for the different speed controls? Although I could be mistaken of course. Can anyone confirm this and maybe what terminals I should be checking for voltage etc.?

 

[Nealh]

It's a cheapo 24v folding bike, the battery will be a generic dumb two wire set up the two outer pins will be wired. Sometime they have =/-- marked, any speed control occurs between the display and the main controller box.

 

[AndyBike]

Unfortunately, I do not have room in the house for the bike. The only thing I was thinking of doing was perhaps using an hairdryer to see if I can dry it out a bit? Just a thought of course.

If you dont have room i suggest you either make room, get used to walking around it to get into whichever room/area its blocking or look to insulating your shed.
Any dampness isnt going to be on the surface and could well be deep in the wiring where the heat of a hairdryer isnt going to reach. Ebikes as suggested really need be kept in a warm dry environment.

 

[chris301up]

It's a cheapo 24v folding bike, the battery will be a generic dumb two wire set up the two outer pins will be wired. Sometime they have =/-- marked, any speed control occurs between the display and the main controller box.

Its not the most expensive bike, by far, but certainly not cheap compared to some others. Its not a folding bike either. The main power is, as you mentioned, from the two outer pins, but there is also power of around 2.5 volt from one of the other centre pins. Without stripping it down completely, which I'm not going to do unless I need to, then I have no idea what this connection wold be?

 

[chris301up]

If you dont have room i suggest you either make room, get used to walking around it to get into whichever room/area its blocking or look to insulating your shed.
Any dampness isnt going to be on the surface and could well be deep in the wiring where the heat of a hairdryer isnt going to reach. Ebikes as suggested really need be kept in a warm dry environment.

I cannot find room anywhere in the house but I never had any issues with my previous e-bike being stored in exactly the same place. I appreciate your comments and will, when I have time, investigate further. It may mean that I will have to strip down the electrical items, such as the handlebar displayer and battery pack, to get at the controller so that I can use the hairdryer deep into the electrics.

 

[Nealh]

We haven't had any voltage readings yet !!!

 

[chris301up]

We haven't had any voltage readings yet !!!

Yes I have posted voltage. Fully charged 27.2 volts.

 

[Nealh]

27.2v fully charged means the battery is knackered or has a very bad cell group, no wonder the bike doesn't work and the screen turns off. The voltage is sagging horribly or simply collapsing.

27.2v = 3.88v max per cell group, this equates to approx. 70% or a knackered battery.

 

[chris301up]

27.2v fully charged means the battery is knackered or has a very bad cell group, no wonder the bike doesn't work and the screen turns off. The voltage is sagging horribly or simply collapsing.

27.2v = 3.88v max per cell group, this equates to approx. 70% or a knackered battery.

How do you arrive at this? It's a 24 volt bike. My old 36 volt bike used to return a reading of around 40 volts on the multi-meter.

 

[Nealh]

It's simple maths, 36v has more voltage then 24v but the maths are exactly the same, one divides the voltage by the cell group numbers.

24v is 7 cell groups in series aka as 7s/24v, each cell group has max voltage of 4.2v. A max charge is 29.4v so a max charge of 27.2v divided by 7 = 3.88v = a defective or knackered battery.
I would be concerned if a 24v battery didn't charge to 28.7v let alone a poorly 27.2v.

36v is 10 cell groups in series so 10s, again each cell group is 4.2v max.
44v is 12 cell groups, 48v is 13 cell groups etc,etc.