Battery charges… just not enough

Hey all, when I bought my 99 VFR800, the battery wasn’t charging at all. Starter relay was fried so bike wouldn’t start, replaced it, notice the battery is not charging. Go hunting for new R/R’s.. $160!? I’m a broke high school student, so I scour eBay for a bit and find one for $19. Receive it, throw it on the bike, and now my battery charges, but not fast enough. I want to say the stator is bad, since I haven’t messed with it, but I read 60VAC across all 3 pins @ ~5000 RPM. Any other tests I can do for my stator and/or R/R? should I replace the stator and/or R/R (again)?
Some additional info: battery charge is lowest at idle, around 3000 (-/+ 500) RPM is when my voltmeter seems to peak when im at a light. If I’m going to get a new R/R I think I’m going to go MOSFET, any good kits for a 99 VFR? Whatever the answers are to all of the above questions, whats the best budget stuff I can get? I am a high schooler who spends all day at school and hardly have any time to put in any hours at my job, so my budget is tight. Thanks Y’all!

 

Hi Connah.
When you measured your 60vac were you back probing the connector with it connected to the R/R. Or measured open circuit voltage, plug disconnected from the R/R? If you were simply back probing those voltages sound pretty good. The only other stator check is to confirm you read infinite resistance of each of the three phase wires to Ground. Low resistance to ground = dead stator. However with 60vac per phase I doubt you have a dead stator.

It's very important that you have confidence in your multimeter that it's reasonably accurate, I've certainly dealt with guys chasing moonbeams all due to a faulty meter!

You haven't mentioned the all important DC voltage at the battery, measure this at idle and 5000rpm both cold and hot engine. If you are seeing around 13.2 to 14.5vdc then your charging system should be ok.
It's vitally important to confirm that the three wire stator connector at the R/R is in good shape, no sign of burning or heat stress AND that the R/R output connector is also in good shape. And make sure your battery connections are clean and tight.

Also what is the status of the bikes battery? Is it at or near the end of its life? Possibility of a shorted cell or sulphated cells? If you have any doubts about the state of your battery, charge it then take it to any good automotive store and have the battery Load Checked for free. Remember, battery terminal voltage is Not a true indication of its ability to deliver heaps of amps when cranking the engine.

The MOSFET shunt type FH020AA R/R seems to be a popular and reliable choice for both 5th and 6gens.

 

Thanks for the reply. The test i ran was testing each phase connected to each other while the stator was unplugged from the bike. As for battery volts, it never, ever, ever goes past ~13V. It might hover around there at the start but once youve been riding, it’ll be anywhere from 11.7-12.6. I’ll check resistance tomorrow, but I do know there’s no continuity between the phases. R/R wires don’t look burnt. AFAIA, the battery is good, the previous owner did a battery test when he sold it.

 

anyone seen these? https://tenpeaksmotorsports.com/pro...-1999-honda-vfr-800-interceptor-31600-kv0-008

 

11.7 to 12.6 is definitely no good!

Umm Ahh you better hope you DO have continuity between Phases! Should read between 0.1 to 1.0ohm.

You want No continuity between Phase to Ground.

Can only suggest go with a quality genuine FA020AA MOSFET R/R. Cheap and nasty is just not worth the risk. YMMV!

 

No continuity between phase and ground— that’s what I meant, my bad. (I’m sick and running on like 4 Tylenol, so forgive me if I’m a little incoherent).
If I recall correctly, I attempted to test for resistance between the three phases and got 0.0. I have my multimeter set to ohms, should I be testing in continuity mode instead? I know the continuity meter on my multimeter comes up with a number that I’m assuming is resistance when continuity is made. I’ll double check everything tomorrow

 

No worries mate I appreciate your situation, my own health situation is not a good one either, to the point where sadly, I can't ride my beloved 8gen!

A standard multimeter is not the best for very low ohms readings and lead resistance needs to be taken into account, just set the meter to the lowest ohms range. Suffice to say, if you had a dead short phase you would not see the AC voltages you've measured on each phase. And that pretty well also applies to a phase/ground short.

 

Just reading through all this..... adding to what Grum says, the first thing to do is make sure the battery is fully charged and in good condition... it can suck down the charging voltage if failing or partly sulphated...... perhaps try another fully charged battery and take your readings again.

The stator sounds OK, I think, however on this bike the regulator wiring goes through a few connections including the starter relay... all potential locations for heat and oxidation of connections..... the Roadster Cycle harness for example, bypasses all that and takes it straight to battery, eliminating the bike's wiring. However, that means upgrading to a mofset with those connectors, e.g., FH020AA.

Anyway...... back to the beginning..... your battery must be known to be OK first thing.

 

Just taken a cont test. Getting continuity to ground on all phases. What now?

 

Sorry!............You clearly stated previously that you had.....
"No continuity between phase and ground— that’s what I meant, my bad."

If you have the Stator 3 wire plug disconnected from the R/R, one meter lead on Ground and the other probing the stator output wires (not the R/R side!) and you're seeing continuity (virtually zero ohms to ground), then your Stator is toast, shorted to ground!

How is it possible you are seeing 60vac coming out of it?

What happens to this 60vac if the connector is plugged back into the R/R? Does the voltage die? Back probe the connector while plugged into the R/R, what happens to the AC voltage?

1. As has been mentioned by two of us. You MUST establish you are working with a healthy battery.
2. Cheap and nasty, or second hand condition unknown R/R's are bad news.
3. The interconecting wiring and plugs from stator through R/R to battery need to be very closely looked at.
4. Stator checks are simple and clearly explained in the Service Manual. Perhaps other 5gen owners can advise on your Stator best option, be that new if available, or rewind, or non oem equivalent.

Also the R/R feeds the battery via Main Fuse B 30amp located next to the Starter Relay (not the one in it). What is the condition of this fuse AND its wiring? This fuse can suffer badly from overheated high resistance connections, burnt wiring etc.

Good luck with everything.

 

I think I'm going to replace R/R first, then stator, then battery. Need opinions for the MOSFET, Rick's or Roadster Cycle? I hear a lot of positive things about RC, but Rick's is cheaper, 100% plug and play, and they're both MOSFET. Thoughts?

 

Couldn't seem to find a USED one, only aftermarket ones, which while cheap ($30!), are of questionable quality and probably aren't even MOSFET. Roadster Cycle it is... Time to clock into work!

 

I installed a Rick's VFR MOSFET on a 5th gen two years ago when the bike had 50,000 miles on the odometer. The stator plug was half gone, so I direct soldered up the high voltage wires. That VFR is today at 76,000 miles and has had no charging system issues since the install.

 

Damn, wish I had held out for this... Already spent the $200 at Roadster Cycle

 

One thing I noticed; when I'm moving and it's cooler out, the battery stays charged around 12.8-13.2V, but when I'm sitting in traffic it drops down to 12.2 (-/+)0.2V. If I fast idle it the voltage will go up a bit. If I've been sitting in traffic a lot and the engine is running on the hotter side, the voltage will be lower.

 

Did you ever get battery checked.

How old is it ?

Symptoms you describe are commonly associated with a dying battery that the R/R is struggling to charge.

 

The money spend at Roadster Cycle is not wasted, you needed to do that anyway.......