battery wont hold charge

[taffo]

hi,
please help! i am new to biking, only been on two wheels for 5 months now. so based on all of the great reviews i found, i bought myself a k1 sv650 as my first bike. (low milage, looks great fully faired)

all has been great, until i let the bike get a little wet! the bike just wouldn't start. after reading other posts on the forum i decided that it was just an old battery not holding is charge, and the wet thing was a coincidence.
So step one - bought a trickle charger. unfortunately even after a good charging, the bike failed to start. relay, starter motor etc checked, all runing fine, just not enough juice to flash the spark plugs.
Step two- bought a new battery. woo hoo! she runs. over the following few days did about 50 miles, no worries. weekend before christmas decided to ride home to my parents in south wales from my home near southhampton (aprox 150 miles). great run no problems, parked up in southwales, in came the rain. just two hours after my long run, and the bugger wont start!

i put the bike in a friends garage over night to dry out, still wont start. i charge the battery for a few hours. its like nothing was ever wrong.
I ride the bike for 20 mins, park up, its raining a little, she fails to start.

so here we are. i know riding in the rain is not always fun, but its is sometimes required, any one have any idea why this is happening? i have 2 days until i have to ride back to southampton, i dont fancy riding for 3 hours without a single stop, just in case the bike wont start again!

cheers in advance!
taffo

[neio79]

Alternator/ Regulator or rectifier are likley to be the problems, not charging the battery while running.

[jambo]

search for charging circuit and you can test if the alternator and reg/rec are doing their job (Alternator generates electricity at ~80V AC, regulator/rectifier turns it into a nice 14V DC or there abouts)

If this comes back fine check for loose connections to the battery or starter motor relay and see if any part of the loom seems to be getting wet and shorting out.

[Stig]

Something else that I learnt recently.

If you have a meter that checks Ohms. Disconnect your battery. Switch the meter to Ohms and connect the meter to the leads that go on the battery. If you have a reading around the 1000 Ohms mark this suggests that you do not have a voltage leak on the bike. The lower the Ohms reading the bigger the voltage leak/short.

This will at the least either confirm or negate a voltage leak on the bike and will give you a positive direction to go or not.

[taffo]

thanks for the quick responses. i have a new development.
i took the battery off with the intention of charging it tonight, only to test its output before beginging.
At this point i was suprised to find that my battery is actually still giving out morethan 12 volts! i had only assumed that the battery had lost its charge again becuse i was not getting a spark but was getting the relay click and starter whirr. (the sprak plugs are less than a week old and are a good colour)
im not at home with the bike yet, so my tools are limited. the voltmeter i am using is as old as i am (27) and isn't very accurate (swinging arm display). i can get a rough idea of output(s) but i don't trust it enough to spend £80 on a new rectifier. any one know of any other test i can do/ posible areas of weakness that would cause shorting?

[neio79]

a battery will still show the right voltage even if its not holding its charge. as charge is in Amps. a good way to see what its charge is to do a load test on it.

[taffo]

looks like you are right. i bit the bullet and bought a better multimeter. as a reslt i can say that there is no leak.
my battery is still not fully charged, so i did the rectifier diode test that i found in the FAQ section. most of the values came back as expected, but the last two ,(b/w+ to y1- and b/w+ to y2-) came back as 0 V. based on this i am going to get a new rectifier.
however i also tested the generator coil resistance this came back at 1 ohm rather than the 0.2 -0.55 that was sugested. does that mean it needs replacing aswell or not?

As you can tell i know jack sh*t about electrics!

[yorkie_chris]

Yellow wires?

Are you on about the test done with the engine running, where the yellow wires are supposed to be showing 50V (AC!!) when checked against ground.

If these are showing zero then its the generator thats faulty, not the rectifier.

[taffo]

no, i cant get the battery to take a charge! ahhhhhhhh!
this test a to disconect the rectifier and to do a diode test accross it. this test is described in the downloadable user mannual thats in the FAQ section.

i am supposed to be riding it home to southampton today. i think i am going to have to take it over to thunder road suzuki to get some proper tests done. i just dont have the tools or knowhow to get this done quickly enough. Thanks for your help though. ;)

[Alpinestarhero]

The regulator/rectifier issue is a common problem and many people on here have had to change theirs; its most likley that if all the other tests have shown everything to be ok then the reg/rec is dead. If you get a haynes manual, it'll tell you how to test the other electrical components and thusly arrive a conclusion that thereg/rec is dead. I dont think water will be an issue, as this would leave to shorting and nothing ever starting (possibly blwn fuses?)

Sid Squid is the man with the knowledge, he might be able to prescribe a test and a solution for you! search for him an send him a private message?

[fatneck]

I know Jack Schitt about electronics too, but try charging with an Optimate SP III charger - sorted out all my battery issues in one fell swoop. Awesome. This was after a cheapy trickle charger had failed to do anything. Well worth buying, because whenever your battery is replaced/sorted/whatever you'll still need an Optimate to keep it tip top anyway.

Worked for me!

[yorkie_chris]

you'll still need an Optimate to keep it tip top anyway.

Or you could actually ride your bike, this works pretty well for mine :-P

[fatneck]

Damn right! Sometimes I just gotta take the car though, so its good to know the Optimate will sort any issues that might be trying to creep up (cold and immobilizer mostly) and stop me starting it...

[taffo]

thanks for the responces, but time was of the essence! i took the bike to a well known suzuki dealer in south wales, who did me a deal on a 'spare' rectiefier that he had lying about (still in the box)! one of the mechanics had a look at the old rectifier did allof the tests that i couldn't to find that the rectifier was kicking out 19 volts into the battery at 5,000 revs, so on my tripdown to wales i had boiled the battery (again!) It looked like a football squashed into a letterbox! i made it back to soutampton tonight with no problems.
I would like to recomend 'thunder road' suzuki bridgend any time. i turnned up with my bike in the back of a van, no appointment and a mood, they were got me back on the road withing a couple of hours, and i was smiling form ear to ear because they had only charged me £125'ish for a r/r, a new battery and the labour. cheers guys. :)

[Stig]

Blimey that is a good result. Well done you. :thumbsup: