FH020AA Overcharging after 2.5 months of use

As if there weren't enough threads about charging systems and how to fix em and so on.

Well, Beginning of the year I had my second factory R/R kick the bucket so i came here, read for a day and bought a new FH020AA Yamaha R1 R/R.
Installed it, ran tests and it was working exactly as intended without issues. I made a new wire harness with 10ga wire going to battery and stator wires. On the pos. side I put a 30A fuse inline and the ground was straight to battery.

Well today after about 4 hours of riding I look down and my bikes running but the gauges are down as if the bike were off. Pull the clutch and the bike dies. Yep. Dead battery. Sheit...

Well, the inline fuse was melted. I mean, it didnt blow, it just straight up melted and the water proof fuse holder melted with it to where there was bad contact.

I put a spare 20A in just to see if perhaps it would work and I bump started the bike and it starts! Well, I keep the revs up and I let it recharge the batt some and then let it idle while calling my friend to let him know i havnt moved and its idling. I get off the phone and the gauges are off again but the bike is running with super low idle. I turn it off, look at fuse and its popped. Stuffed the bike in a truck bed, just got home and pulled the battery and onto the charger it goes.

The R/R was not hot. The wiring was not hot. Everything is soldered and heat shrunk. The battery though. WOO! she was a wee bit warmer than normal. But of course, poor thing was being fed too much for god knows how long.

So, Anyhoo; Anyone had this issue before? Because honestly here... this is craycray man. Tomorrow ill do voltage testing again but I think I saw over 16v to the battery before I pulled it again while in the garage. That was at idle too.

I mean, it was a brand new unit but I honestly cant remember if it was in the original box or what.

I did look at other forums first and some dude had an issue of undercharging but his issue was that he soldered the 10ga wire to the stator leads and after hooking them up dry without any solder, it worked. That sounds like a bad solder job and not hardware. It happens. My solder joints are fine as noted by 14v idle and 14.5v at roughly 5k rpm when i initially installed the new FH020AA.

 

You obviously haven't fitted a voltmeter, that would have told you right away there was an issue with the charging, way before you ended up stranded and damaged your battery which the overcharging may have already done

 

Well yeah. that one is obvious. Which is why while waiting, I bought a volt meter with audible warning. But again the question was about the FH020AA unit and the failure rates. Looking to see if anyone else has had the issue.

I probably should also note that the previous owner had swapped the second OEM R/R. I wired in the FH020AA after that second one died. But that one wasnt charging and had an open in the internal circuit.

 

My guess is you had a bad connection at the fuse, or else it wouldn't have melted like that.
Higher voltage will not make a hot joint, boil the battery yes but not melt your fuse.
The R&R might be toast.
Haven't heard of too many FH020's failing, but bad connections can do all sort of damage.

 

OZ is correct, it is the CURRENT not the VOLTAGE that is causing the heat problems, current through resistance of a poor connection generates heat.

 

Next we will be soldering the wires to the fuse legs!

 

Yeah, I understand the amperage with any resistance creates heat as a biproduct. What gets me thinking more into it is if it was generating enough current where it was bordering the 30A max load and thus creating a hot fuse. However I would think thats wrong as the fuse should be thermally stable until 30A cross and it pops. My thought is there was a break but small enough to allow an arc. I am about to do more testing on it.

Kind of odd that I have read everywhere else, or most other sites, and no one seems to have this issue. I was trying to look up how to check for actual authenticity of the R/R just to be fully sure. Color and stamp matched but these days, its not hard to clone things, ya know.

And as for the soldering the wires to fuse legs, I pretty much did that since I soldered the waterproof fuse holder to the power wire to batt and that fuse has a tight fit. I need pliers or a fuse puller to yank that fuse out (even before it got toasty)

 

Bad connection somewhere is the cause of heat, these things run such a fine line that the slightest problem causes big problems. I am assuming you used one of those mini blade fuses? they may not be up to the current draw even though they are rated 30 amp

 

NormK, I seriously logged in just to confirm that myself.

Put the battery back in and first tested the R/R which all came out with flying colors. Started it and let it warm up. So here is where I need to correct myself and so on...

My initial post said I tested the R/R when running and it was hitting way over voltage numbers. Pretty sure I might have read the meter wrong by a long shot as the batt. voltage on cold start running is 13.97 and hovering around there. It actually moved a good bit. Remember that.

Once bike was warmed up a decent amount and idling for 3 min. I slowly revved to 3K and voltage read around 14.04. Again, moving around a good amount.
Rev it to 5k and voltage never exceeded 14.55V

So, by that time, I was watching the mini 30a fuse and in the beginning it looking kind of like it discolored but i couldnt remember what the before look was. After running for a total of maybe 4 minutes the fuse leg started melting the plastic fuse body (same leg that got crusty the first time. I shut the bike off and checked voltage to each part of the fuse holder and the toasty leg was seeing .8V and the other side was seeing 13.1V (bike off) Tested the fuse and it had no resistance so I am now looking at switching to an auto resetting breaker and its associated holder.

That wandering type of voltage was what got me thinking about the fuse first. My initial testing back when I installed the unit, showed a steady voltage signal every time.
So, Because I might have been pretty tired and a little hungry, I might have read the multimeter wrong yesterday. This happens from time to time...

 

Sounds like your R/R is ok, problem is after cranking the bike over to start, or running with your headlights on, the R/R pumps pretty hard to replenish the battery which sounds like too much power is trying to go through the mini blade fuse, the bigger type blade fuse should handle it but if it doesn't there is another problem somewhere. Sitting at the lights, headlight on, holding the brake so stop light is on and fans running draw a lot of power through that fuse all at one time

 

Yep. I am going to be wiring in a new fuse holder but for the maxi fuse.

 

I have had my FH020AA reg/rect for over 3 years with zero issues and have not heard of any failures either. I would go with what NormK said.

 

Yeah. Last night I wired in an ATC 30A fuse. Either today or tomorrow I will test it again.

 

Just to seal this thread off, I rode the bike for 2 hours last weekend with no issues. I had to see the newly open tool store near me and bought a temp gun as well.
the ATC style 30A fuse sees 91 Deg. F when bike runs. never got much warmer. So, To anyone that finds this thread later on, My mistake was using the wrong style 30A fuse along with the wrong rated fuse holder. Don't do that or you're gonna have a bad time.
Honestly im impressed it lasted from march until June like that with almost 1000 miles.

 

Scoots, good to hear