Odd battery problem

Hello everyone - hope some of you knowledgeable people can shed some light on this; -

I had the battery of my 2014 Oxygen eMate re-celled by the near-legendary Jimmy back last October and until recently the performance has been better than ever. But now after I have done 6 or 7 miles, the next time I turn the key the battery indicator shows 1 bar and continuously flickers, delivering no power whatsoever. The last time this happened I took off the battery and when I replaced it the following morning (without adding further charge) the battery came fully back to life as if nothing had ever been wrong. Clearly the problem isn’t the battery itself and Jimmy was utterly baffled, so I wonder if any of you experienced people might be able to offer an explanation. Thanks in advance.

Resolder the wires on the back of the key-switch. Use plenty of heat because there's a lot of metal in the terminals.

If it's not that, it's a simple connection issue. You just have to find it. Maybe check the bullet connectors at the controller first.

Other than that, you have to get the meter out and follow the voltage from the battery until you find the point where it drops. Start with the bullet connectors on the controller when you have the problem. No point in checking if everything is working. If you have full voltage there, the problem lies between the Controller and LCD's PCB. If you don't have the full voltage there, work back to the battery.

Resolder the wires on the back of the key-switch. Use plenty of heat because there's a lot of metal in the terminals.

 

If it's not that, it's a simple connection issue. You just have to find it. Maybe check the bullet connectors at the controller first.

 

Other than that, you have to get the meter out and follow the voltage from the battery until you find the point where it drops. Start with the bullet connectors on the controller when you have the problem. No point in checking if everything is working. If you have full voltage there, the problem lies between the Controller and LCD's PCB. If you don't have the full voltage there, work back to the battery.

Many thanks for this vfr400, I am not at all ept (opposite of inept) in matters electronic, but during lockdown I changed the pickups on my guitar, just to see if I could do it really, so I do have some practical experience of using a soldering iron. Diagnosis is always the key in these situations since if I prove too incompetent to solve the problem myself then at least I can direct someone with greater skill and experience. Once again, I am most grateful.

I had an E Mate City for 5 years and also had a larger battery made up by Jimmy. It was a 20Ah and I never had a problem but on a periodic check of the controller box I found that some of the wires were beginning to fuse together, presumably with the heat generated in that confined space. I have had similar problems on other bikes with the Phase wires fusing and this caused intermittent power loss like you describe.

If yours is the the City my first check would be to remove the side plates of the controller box and see if everything is ok in there.

You don't need any special skill to fix these sort of problems. determination and advice from here is enough. Like Steven said, start with that controller compartment. The motor phase wires are the thick blue yellow and green wires that have crappy bullet connectors, which can cause the wires to get hot and melt. When it happens, any numbskull should be able to see it if they look.

also in that compartment are the thick red and black battery wires with bullet connectors, it's always a good idea to pull them apart, crimp down the outers a bit, then reinsert all the way to make sure that they're tight.

The keyswitch is also very easy. You undo the 4 screws that hold the top plastic part of the battery, lift it off, then remove the two screws that hold the key-switch. You have to wiggle the key-switch out by pulling it forward to get more clearance at the back. Once out, you can check the two solder joints with a magnifying glass for cracks, though sometimes they look like they're soldered, but there's a dry joint, which you might see when the whole soldered bit moves when you wiggle the wire. In any case, it doesn't do any harm to re-heat it until it melts and keep it like that for about 5 seconds to make sure that all the solder is properly fused.