New battery on son in laws max

[josephjhaney]

So, the son in laws lithium ion battery finally bit the dust (He's riding my 85 max, and I had this battery installed so that's the one I bought again. https://a.co/d/3AdpLQG
He was riding in to work today, and the lights started flickering, the volt meter went up to 20, and then he stopped for gas since the low fuel light came on. The bike wouldn't start after that, was just clicking, I went to help, it started fine on a jump pack, but as soon as we took the pack off, more flickering neutral light, jumping tach, etc. I'm thinking loose connection to the battery, but he had to get to work so the troubleshooting continues tonight. Just wanted to get some other thoughts here while we wait for our respective workdays to be over and go try to get her running.

Joe

 

[MaxMidnight]

Assuming the voltmeter is telling the truth then it would suggest the r/r has failed and cooked the battery.
You need to check what is the battery voltage with everything off and what is the charging voltage with the engine running.

 

[Radioguylogs]

I'm sure you will check the Rectifier Regulator charging voltage if you can start it. The 20V reading on the voltmeter makes me think the R/R was headed for the graveyard.

The battery will be dead after the R/R fails, so no surprise if the bike won't run with no battery and no charging power.

However, the flickering lights don't seem consistent with an R/R failure.

 

[josephjhaney]

Ok, I upgraded the Regulator/Rectifier to a new version, I want to say in 2014 or so, I suppose it's completely possible it bit the dust. I'll snag one of those just to be safe and if it doesn't need it, it can sit on the shelf till it does.

Joe

 

[josephjhaney]

Update, it was a fried regulator, replacing it resolved the issues. Thanks all!

Joe