Flat Battery Caused By Water

[metalguru]

Went to start my bike the other day, switched the key on and....nothing. The battery was completely flat with not even a glimmer.
I put the bike on the mainstand (this is very relevant) and started the fault finding.
Nothing obvious showed so stuck the battery on charge. Gave the battery a drop test and it passed, recharged to full again.
After a while on the charger the engine came to life, checked the charging and that was good too.
Switched it off and dropped it off the mainstand to return later for a ride, still a bit mystified.
Came back after a while and the battery was dead flat again and rather warm!! The battery is a recent (2yr) Motobatt and has been great with no false starts or problems.
Connected up the jump leads thinking with this loss in a short time the fault would show or the loom would melt!!
Sure enough when I connected the leads, I saw a small spark at the battery terminal and the headlamps came on, bearing in mind the keyswitch was off??? Disconnected the jump leads and put the bike on the mainstand for additional fault finding, connected the jump leads back up and no spark or headlamps??????

Working through the findings, the only way this could happen is a faulty relay.
Started checking the relays and got to the lowest relay (they are at the front of the tank on the left hand side behind the fairing) finding the cover was wet and evidence of rust stains. Not all bikes will have the lower relay.

Pulled the lowest relay and found discolouration.



When the cover of the relay was removed found the cause,



The corrosion stains traverse the coil feed and the +ve feed so energising the relay, lighting the lamps and hence a flat battery.

The relevance of the bike on the mainstand was, the water in the relay case went to the front of the case uncovering the feeds and hence no fault as the rear of the bike is higher. With the bike on the sidestand the water came towards the connectors and diagonally traversed the two feeds, hence on came the lamps 2X100W.

May be worth a check next time you are near your bikes as it is possible to check by removing the left hand indicator and only takes a few minutes. The 5 pin relays are fitted to all modern cars and are plentiful in breakers yards.

Hope this will help some keep their hair as it was a bit tricky to find.

[Bixxer Bob]

I love faults like these, as long as it's not my bike    There's a lot of satisfaction to be had when you finally crack it