Battery Charge

[foxy54]

This one is frustrating me. I recently replaced the battery on my max, but it goes flat real quick when I don't use the bike. I charged it today and went straight out, I got home and went to start it an hour later and no dice. Charge seems ok with 12v at idle and 13.5 to 14.0v at 3000 rpm. Do I have a duff battery anyone? :damn angry:

 

[DMAN999]

I'd take it to an auto parts store and have it load tested.
Also run through this Trouble shooting guide to be sure your R/R and Stator are working properly:
http://www.vmaxforum.net/showthread.php?t=19108

 

[foxy54]

Thanks for your reply. The whole charging system has been replaced just recently, and as I said the voltage outputs at the battery look fine or am I wrong?

 

[DMAN999]

Like I said have the battery load tested almost any auto parts store will do it for free.
And 12V at idle is about 1 Volt lower than it should be and indicates a charging problem.
Read that guide I linked to.
You should also make sure your ground wires from the battery have good clean connections.

 

[foxy54]

I will get the battery checked out as you suggested. Then based on the outcome can determine my next steps. Although I have checked the output again and was wrong on my original statement, the voltage at idle went between 12.7 and 13.0v.

 

[Miles Long]

Not unusual for a brand new battery to be a dud, but if it turns out to not be the problem, something may be draining the battery while the bike is off. Easy to check with a meter. Enter "parasitic battery drain" into a search engine, and oodles of step by step instructions will come up, many with videos
Cheers!

 

[foxy54]

Thanks Miles, all advice gratefully received.unk:

 

[thor_eyerdhal]

How many RPM at idle?, 12V seem a bit low, i have 13.8V at 1100 RPM and 12.5 at 900 RPM...

 

[foxy54]

I got the reading wrong, 12.7v to 13.0v at just over 1000rpm, and around 14v at 3000rpm.

 

[Miles Long]

I got the reading wrong, 12.7v to 13.0v at just over 1000rpm, and around 14v at 3000rpm.

Not bad, Foxy. Should be "good to go"
An on-board voltmeter is an inexpensive and valuable addition to the V-max, given the history of charging-related problems with the bike. Many folks on this forum have already done this mod.
If your bike is totally stock, the maximum continuous draw on the battery will be when the high beam, radiator fan,and brake light are all on. If battery post (or voltmeter) reading is above 12.4 or so (at idle), the charging system and battery are fine.
There are a couple simple modifications that can be done to maximize the potential of the stock charging system, but with your present readings they are not needed.
Cheers!

 

[foxy54]

UH OH Miles. Checked the bike more extensively earlier. On start up beautiful voltage output at 1000 RPM of 13.4v but after about 5 minutes at idle the volts dropped to 11.4 and totally wiped the battery WTF is going on? I'm beginning to think the reg/rec. What do you think? :-(

 

[Miles Long]

UH OH Miles. Checked the bike more extensively earlier. On start up beautiful voltage output at 1000 RPM of 13.4v but after about 5 minutes at idle the volts dropped to 11.4 and totally wiped the battery WTF is going on? I'm beginning to think the reg/rec. What do you think? :-(

I think that you will have to check the charging system from stem to stern, as per Mr. Dman999's suggestion in the second reply.
RaWarriors's original thread is very thorough, and contains many other hints and suggestions from other people. Post #10 of the thread is a link to the Electrosport fault-finding chart - excellent, but generic. You have to sift through the info for things that apply only to our bikes.
Yes, your problem could very well be the RR, but it could also be related to the stator itself. Sometimes, they perform great when cold, but after heating up, they develop internal shorts, and fail to put out wattage.
By disconnecting the three-wire stator connector, you can check for this condition, both hot and cold.
Good luck, keep us posted!

 

[foxy54]

My bike threw me a curve ball. It showed 13.4v at 1000rpm and then within two minutes dropped to between 10.8 and 11.4 volts. WTF is going on?

 

[foxy54]

Sorry Miles I posted before I read your response, the site has been playing up my end. Where do I check the stator output, is at the connections to the RR?

 

[Bill Seward]

Check output voltage - it will be AC, remember, by measuring voltage across any two of the 3 white wires emerging from the cases. This is 3 phase AC, so you want to check every combination of two wires (1-2, 1-3, 2-3). If you notice any defect in the 3 connector plug, that looks like it may have partially melted, or gotten really hot - you should remove the plug completely, just cut the wires off both ends. The remaining wires can be soldered together. Being AC, it does not matter which stator wire you solder to which R/R wire - just be sure to do a good job, and insulate them well.. From each other, as well as ground!

Lots of these plugs fail due to corrosion causing increased resistance in the plug. This causes excess heat at the point of resistance, and can lead to a hot, melted, or even burning connector. Mine smoked, and has been soldered for the last 20 years. I had to replace a couple R/R units over the time, just a bit of soldering and heat shrink tubing, and it's as good as new...

Output voltages across any two of the stator wires should be about 50 (there is a wide variance here that still is considered OK), but should be within a few volts of each other. You can also measure resistance of the stator coils, and measure for shorted phases of the stator. I don't remember what the resistance of the stator coils is supposed to be, something like .5 ohms seems right. If you have zero ohms between any white wire and ground, the stator is shorted to ground and is kaput. Others have posted info on how to test these functions.

 

[foxy54]

Thanks Bill. I will give it a go.