Kelum Posted July 11, 2011 Share Posted July 11, 2011 Week ago I bought a new battery for my xv125, filled sulfuric acid to upper level and let settle overnight..and installed it and last night I the headlight was flickering..dimming and brightening So I removed the battery to find out all the acid levels in 6 cells to have gone down terrible, no didnt get rotten egg stink. I think my previous battery was ruined by the same case, it too had fluid level running down issue frequently..now that I have placed a good battery so I think regulator not doing its job properly. I checked the bike circuit and found 3 white wires coming from AC Magneto connecting to regultor/rectifier and all the wires are presently connected as per the diagram below. Uploaded with ImageShack.us I have to make a special note, right after few days I bought the bike, rectifier died, so I bought a new one with the similar code, it was a one disassembled from a virago..code is SH6400D-12...I wonder if the guy who installed the second rectifier messed the wire connections in the socket, I would really appreciate if someone could post his wire connection configuration to the rectifier here. Seems the rectifier I bought was a faulty one. It kills batteries..am scared if my new battery has been ruined already..please someone help..thank you.. P.S. in my previous battery I had light flickering, fluid run-down issues plus in worst cases, SO2 formation..sulfuric goes away as sulfur dioxide...rotten egg under my seat.. Link to comment Share on other sites More sharing options...
Kelum Posted July 12, 2011 Author Share Posted July 12, 2011 anyone please? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 12, 2011 Moderator Share Posted July 12, 2011 kelum top up your cells with de-ionised (distilled) water. With a multimeter on the battery terminals measure the voltage when the engine is revved to around 5000 rpm's and report back. Link to comment Share on other sites More sharing options...
Kelum Posted July 12, 2011 Author Share Posted July 12, 2011 ok bt since bike doesnt have a rev counter how can I check revs at 5000? regulator not doing its job for sure mate..will see.. Link to comment Share on other sites More sharing options...
Kelum Posted July 12, 2011 Author Share Posted July 12, 2011 Rectifier. When a coil produces electricity, it sends it out in plus or minus waves. The battery can only charge on one of these waves. A rectifier has silicon diodes that only allow half the wave to get through. Back in the 60s and 70s a lot of the little bikes had these single wave rectifiers. Now most bikes have full wave rectifiers that have four diodes. All this rectifies the AC current to DC to charge the battery. To test the rectifier, hook up the ohmmeter leads to one of the wires and to the ground (mounting) stud. Note the reading you get. Now reverse the leads from the ohmmeter and note the reading again. The exact reading is not all that important, but there should be a big difference between the two if the diode is working right. Test each of the wires this way. If any wire is very close in the two readings then the diode is leaking and no good. If there is no continuity, then the diode is shorted out and no good. Be careful not to turn the bolt holding all the diodes together. This can short them out. It is possible to test the rectifier with a circuit tester by adding a D flashlight battery in line with the circuit tester. You want to see the light, light in one direction and not in the other. If all of a sudden you start blowing the main fuse, it's possible one of your rectifier diodes has failed, letting current, from the battery flow back to ground. Voltage Regulator. All the current from the charge coils would over charge the battery if we let it, so we need a voltage regulator to keep the battery charged at 12 volts. Your ohmmeter should have a DC volt scale. Set it at 20 volts and connect the positive and negative leads to the right battery terminals. Make sure the battery is fully charged, so we get a correct reading. Start the bike and rev it up. The volts should go up to 13.8-14.5 volts and then stay there. Much more, and it will over charge the battery. Much less, and the battery will never charge up. Some voltage regulators can be adjusted and some cannot. If you can't get it's cover off or if it is all sealed up, it's non adjustable. If you can get the cover off, you can clean the little contact points and adjust it with a screw driver till you get the right charging rate. Most, nowadays, are not adjustable. Most of the newer bikes have the Rectifier and Voltage Regulator as one unit. If either one goes you have to replace both. AC current will light the headlight and everything else. Light bulbs don't care if it's DC or AC current. If you have a dirt bike and don't need a battery you can get an after market voltage regulator for $30-40 and it will keep you from blowing bulbs. A number of the older, smaller, bikes had no voltage regulator. I guess they thought the battery would soak up the extra current... they were wrong, so put one in. There also is a cheap after market rectifier/voltage regulator unit you can put on, if you need a battery. It will also work on some street bikes too, but you have to make sure it matches the charging system. Link to comment Share on other sites More sharing options...
Kelum Posted July 15, 2011 Author Share Posted July 15, 2011 kelum top up your cells with de-ionised (distilled) water. With a multimeter on the battery terminals measure the voltage when the engine is revved to around 5000 rpm's and report back. Mulitimeter gave an 18.1 voltage reading at medium revs on battery terminals. Bad rectifier/regulator... Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 15, 2011 Moderator Share Posted July 15, 2011 Mulitimeter gave an 18.1 voltage reading at medium revs on battery terminals. Bad rectifier/regulator... yes it seems so but check it has a good clean earth before you buy a new one Link to comment Share on other sites More sharing options...
Kelum Posted July 15, 2011 Author Share Posted July 15, 2011 yes it seems so but check it has a good clean earth before you buy a new one Please explain how can I check the earth buddy? U mean the earth lead connecting from battery to crank case? or are you referring to the earth lead connected to the heat sink of rectifier/regulator? please advise! Link to comment Share on other sites More sharing options...
Paulwhite Posted July 15, 2011 Share Posted July 15, 2011 both lol the one on the battery and the one on the reg/rect, they should be clean and the one on the reg/rect should attach to the frame (where there is no paint as ur frame acts as an earth) Link to comment Share on other sites More sharing options...
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