[null]

My Mahindra Centuro bike was idle during this covid period. Wanted to bring back to running state - tried to start it a couple of days back, but the neutral indicator or blinkers were not working (after a brief glow) due to battery gone weak without using. As expected, gave the battery for charging last evening & got it back a while ago. Battery was a bit warm when I collected it.

Came home and hooked up the battery, turned on the ignition and pluck the 15A fuse blew off. Had 2 spares n both gave away the moment I put them in.

Bike was working fine i.e. running well 4-5 weeks back. Had got a new battery 2 months back. The bike was not running much and the new battery got discharged quicker than usual (my assumption - coz it was new n was not fully charged).

So, What could be the reason? Over charged battery?

Any tips on diagnosing & fixing it? (Not really game to push the bike to the battery shop).

Thanks.

[srini1785]

Originally Posted by null

So, What could be the reason? Over charged battery?

It looks like you have a short somewhere in the circuit. IMO, The battery should not be a problem. I suggest that you check the ignition key itself as the fuse goes phut the moment it is turned ON. Its rather difficult to trace such faults by yourself. It may a very simple matter to more complex faults.

If you have a multimeter then connect one end ( red ) to the outgoing of the fuse holder and black to the negative ( frame) and set the multi meter to continuity tab. Now turn on the ignition switch. if you have a beep sound then the switch is getting shorted somewhere.

[saket77]

There’s definitely a short in the circuit somewhere. Battery isn’t the issue.

Check the positive wire if it’s outer insulation has worn off or bitten by rats and it may be shorting with the body/ chassis metal parts.

Regards.

[Jeroen]

Originally Posted by saket77

There’s definitely a short in the circuit somewhere. Battery isn’t the issue.
.

Fully agree, you need a healthy battery to blow a 15A fuse. So you have a very big short somewhere!

Good luck

Jeroen

[nagr22]

Have you checked whether you have connected with correct polarity? If the + and - terminals have been interchanged then also this can happen.

[deep_bang]

It's very common for rats to chew up wires and cause shorts. Very carefully look at wiring if there is any evidence of the insulation being removed - I bet there is a short due to the rats chewing away the wiring.

[ArizonaJim]

Rats eating the wiring insulation is a good possibility.
Another good possibility is, when the battery was being recharged, some cover needed to be removed.
There is a chance that when the cover was replaced, one of the wires was pinched between the cover and the frame, or another wire.
The problem might not be immediate. For instance, a pinched wire's insulation could take some time and vibration to finally wear thru causing the short circuit.

When a mechanic (or yourself) has worked on something and shortly after it was done, a problem suddenly arises, the area where the work was being done is the first place to look for the cause of the problem.

[null]

I could not look into the problem further - could not find the multi meter then, festive holidays happened & the lazy me ruled over me. I had disconnected the leads & closed the side cover then itself. I hope I can check on the points mentioned above this weekend.

I got an update from my nephew, who had used it for a while earlier, that the 10A fuse (it has 2 fuses - 10A & 15A) had blown out and was replaced 3-4 months ago along with a new battery and it was all fine.

But now, for me, the 15A fuse is giving away the moment I connect the leads to the battery & the interesting thing is, it happens even when the ignition key is not even inserted in the key hole. The bike was safe from rains & the rats (I think) & I did connect the battery leads to their correct polarities (we cannot mix it up as sits facing outwards without any mix up & +ve lead comes with a red cap).

Let me check once again over the weekend hopefully after sourcing some more 15A fuses & doing a continuity check with a multi meter as suggested. I guess it is going to be a job for a professional next. BTW I am wary of local workshop guys doing this electrical work since they are not familiar and hence wanted to check if I can do something.

BTW I am surprised that a low end bike like this has an electronic ignition system (does not start - even with kicking unlike other such bikes - without a live battery) and comes with multiple fuses.

[ArizonaJim]

From your description, the problem is the wire between the 15 amp fuse and the ignition switch has some area of it where the insulation has failed. This wire is the main power supply for everything else and it usually does not have a branch wire connecting to it. A possible exception might be, the wire that supplies battery charging from the rectifier/regulator may be connected to it.

This kind of failure might have been caused by a rat but, more likely the problem was caused by a sharp bracket or support that the wiring harness is attached to or the wiring is routed very close to it.

Starting at the 15 amp fuse, first notice the color of the wire. Then, follow it as far as possible to see if the insulation is chaffed, cut or otherwise damaged.
If you find such an area, it can be taped with a good plastic electrical tape to re-insulate it.
If the wire goes into a multi-wire harness, follow the harness, again looking for something that may have cut thru it and the power supply wire that is inside of it.
Again, if the harness has been cut, taping it up with electrical tape should solve the problem.