Not holding charge...Seadoo gti 1999

[Blaked70]

Hey everyone I'm new to this forum so I'm sorry if I'm not upto scratch with the layout etc!

I'm having some trouble with my 1999 gti seadoo 720cc I bought a new battery and plugs yesterday as my other ones were stuffed anyway...however when the ski is running and I take the negative terminal off the battery it shuts down right away! From my common sense (might not be common ) the ski should keep running, correct?? So i chucked a volt meter on the two yellow wires coming off the rectifier at idle and had 11-12 coming through and increased if I rev it but that seems really low. I have 12.7v coming through the red and black out of the rectifier which I believe should sit around 14volts would this mean my regulator/ rectifier is causing the problem. Constant 12.5volt coming off battery terminals at idle

Any help or opinions would be hugely appreciated!

Regards, Blake

 

[mikidymac]

The yellow wires put out AC voltage not DC. The red and black put out DC voltage and should have over 12 volts at idle and about 13.5 volts at 4,000 rpm. Unhooking the battery could cause you to loose connections in the complete circuit. I have never tried to run one with a battery completely disconnected even a dead one.

 

[Blaked70]

Just did a re test yellow wires showed up 0.00- 00.1 for some reason and black and red showed up to 14 I don't have rev gauge but was there abouts at 4500rpm...any ideas on what it could be?

Does that test sound a little bit more correct with yellow wires

Cheers for the reply

 

[mikidymac]

Well if it is running and puts out over 12.5 volts then everything is working.

I wouldn't put anything into the fact pulling the negative battery cable other than you are breaking the electrical circuit.

Now if it eventually runs the battery down and stops running you have a problem but since yours is putting out good voltage it should be fine. These are NOT like a car's alternator and do not put out much power but they will keep it running and the battery topped up.

 

[Chester]

Why are you taking the battery cable off while it's running?

Chester

 

[IDoSeaDoo]

It should be noted that the electrical systems, especially the MPEM (main computer) are very sensitive electronics. Never jump it off another running vehicle, and never reverse the terminals. Many people have cooked their MPEMs doing so. Everyone is correct to say that your voltage should be closer to 13.5 while running. I would also recommend to NOT disconnect the battery while it's running. The battery acts as a voltage dampener. This is pure theory on my part, but I fear that suddenly disconnecting it could send a surge through the charging system and possibly affect the MPEM. Now I do know that you CAN disconnect the red wire on the voltage regulator to test it. Your voltage at the battery should drop and continue dropping as the ski continues running. Sometimes, these rectifiers go bad and cause all sorts of issues with performance, This is a common diagnostic to test for that. The thread says you're not holding a charge. Have you tested for a short? You can do this by using an Ammeter. Basically, you put the two leads in-line with one of your battery cables and the battery. After some time (less than 1min) there should be very little draw. Do not try to start it like this, as it'll blow your ammeter fuse. They're typically rated for only 20A and your starter draws something like 90A.