Africa Twin - MOSFET conversion.

[Loggy]

I have finally got round to fitting the MOSFET rectifier I bought onto my bike. I did the job on Friday. It took me all afternoon to do and I'm fairly happy with the result.

The crimping tool I borrowed from work did a pretty good job at crimping the three yellow wires to their terminals, however it wasn't as good as I'd hoped as the terminals supplied were slightly too big for the gauge of wire. So I had to use some grip pliars to finish the job off and make sure that it was gripping the wire tight. The battery terminals were fine and these didn't need any additional squeezing. I used a hair dryer to shrink the shrink tube to the pos and neg terminals.

I took the old rectifier off the bike and cut the wires off of the round plug at the base. This way, I can leave the plug in the round connector to stop any crap getting in. I re-routed some wires and a bit of jiggling around to get the job all nice and tidy.

The old rec was putting out roughly 13v at tickover, 13.5 at 3,000rpm and 14 at 5,000 rpm (lights off). The MOSFET is putting out about 14.7v at tickover and more or less the same through the rev range. When you switch the lights on it drops to about 14.15v on tickover. This was just a very quick measure with the volt meter and not a proper study of output voltage.

The MOSFET is running virtually cold to the touch, I can't believe how cool this thing runs compared to the (aftermarket) original one fitted. The only thing I have noticed is that the three yellow wires are still getting warm when the bike is running. They aren't scolding hot as they were before where they were very hot, but they are still warmer than I was hoping. I haven't had the bike out for a long ride yet to check how hot they will get, but I had it on tickover for about 20 mins and the heat was luke warm to the touch.

For those of you that have a MOSFET fitted, can you tell me if your yellow wires still get warm, or are they cold? If yours are running cold then I may have to take another look at the terminals and possibly soldier them (don't have a soldiering iron)

I will soldier the terminals when I can get my hands on a soldiering iron to make the terminals as close to resistance free as possible.

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Parts for the job. FH020AA MOSFET reg/rec and Eastern Beaver wiring loom.

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MOSFET Reg/Rec...

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Burnt out connector.

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Old setup.

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That middle plug is the offending little sod. This joins the three phase yellow stator wires to the OEM Reg/Rec. These are notorious for melting on Africa Twins, and mine wasn't any different. Hopefully now that's the job done for the rest of the bikes life!

[Loggy]

Here is the new setup!!

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MOSFET fitted, no modification required to the fitment of this.

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Delphi waterproof connectors throughout. This is the 30Amp fuse holder.

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The round plug is now redundant. I cut the wires at the base so I could leave the plug insitue, this will stop the crud. The MOSFET is wired directly to the battery via the fuse holder.

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Setup done.

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Voltage on tickover, lights off.

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Voltage on tickover, lights on.

[Zenarchy]

I wired one of these into my last bike (an RD04) when the original regulator broke. Was one of the best mods I did to it. Mosfets are way better.

I used a slightly different regulator with pigtails rather than connectors on the top, and in my first attempt I wired the three yellows through a block connector like the bikes original connector.

Found the wires were heating up quite a lot on either side of that connector, so I cut out the connector and soldered the wires instead and this sorted the problem.

The yellow wires did still get warm even then but I was putting it down to simply heat travelling up from the alternator and those wires running close to the engine as they weren't getting anywhere near as hot and the heat was more uniform across the whole wire rather than concentrated in one spot around the connector. Other people seemed to be reporting the same thing when I searched online so I didn't worry about it and it was fine (until some theiving git stole the bike that is - so now I'm on the lookout for another mosfet for the new one - but I have every confidence it would have been remained OK for years to come as I did some long trips with it like that and it never caused any problem).

If you're finding the wires are heating up in one particular spot and getting very hot, then I'd investigate whatever is close to that point as it could be a bad connection causing resistance (which generates heat).

The connectors you're using look much better than the standard connectors on the RD04 though and they look new, so I'm guessing they'll be OK and what you're noticing is just the whole wire getting warm which seems normal.

When there's a point of resistance you can tell because when you start the bike from cold, that particular point tends to heat up quite quickly then you can feel the heat spreading out away from it down the wires.

I think this is actually what the problem is with a lot of the Africa twin regulators. Rather than the regulators themselves being the problem my guess is that it's the shitty connector honda have used as standard for those three wires that's causing resistance and heat to travel up the wire causing the regulator problems.

[Loggy]

Hello Zenarchy,

Thanks for the detailed reply.

Yes the connectors, wiring loom and rectifier are all brand new. The wires are heating up, but are just luke warm not overly hot and they do seem to be uniformly warm. The plug is cooler than the wires so I assume the connections are okay, but I'm going to soldier them at some point anyway. The voltage is rock solid. I'm sure it will provide years of trouble free service. We live in hope lol...

[fella1176]

could this be used on a varadero....

[Zenarchy]

could this be used on a varadero....

If it uses the same type of three phase alternator (I'm guessing it does) then I'd guess so. The same mosfet regulators are used as an upgrade on a ton of other bikes too.

You might want to check the power output of the varadero alternator to make sure you get one with a high enough power rating though. The one I used on mine was an FH008 (I think that's what loggy might have used too?), but there's an FH0012 one that people also commonly use that's rated a bit higher so that might be more suitable if the FH008 isn't up to the job (I'm not sure as I don't know much about the varadero but I'm guessing its a bit better than the africa twin power output wise - then again even the FH008 is more than enough for an africa twin so it's possible it'll be fine - but I'd check to be on the safe side).

There are some other mosfet models too but I don't know so much about those. The FH0011 seems quite popular, but it's really big with a massive heatsink so you might have trouble mounting it in the same position as the original (that's worth bearing in mind whichever one you get infact - apart from the FH008 with pigtails they all seem a bit bigger than the originals or consume more space - might not be such an issue on the varadero depending where it's mounted as the old africa twins though).

Something else to be careful of, is that some of these mosfet regulators have an extra wire (6 instead of 5 wire). That extra wire in some cases is an input wire to be connected to a switched live that the regulator uses to monitor voltage I think, and in other cases it's an output wire used for something else (running lights in some cases I think). The exact mosfet regulator code or checking it with a multimeter will probably tell you what's what if you end up with a 6 wire one, but I'd aim for one with 5 wires ideally then you don't need to worry about what the extra wire is for.

Of the 6 wire variety if it's an output wire, then I think it can just be left disconnected, but the ones where it's an input might need that connected for the regulator to do its job properly.

You should bear in mind this is only what I read when researching doing mine a few years ago, my memory is a little hazy now and I didn't go into a lot of depth about the ones with extra wires (I think this is correct but best to double check particularly if you get a 6 wire one).

[Zenarchy]

P.S.

Just did a quick google and this thread:

http://www.apriliaforum.com/forums/show ... Mod/page27

a post suggests that the FH0012 is used on the varadero. Perhaps its possible newer varaderos use that regulator as standard? If thats the case you might be able to get one that'll plug into your existing wiring and not have to worry about re-wiring it.

Though on the africa twin at least, bypassing those weedy doubled up power wires that run into the loom, and going direct to the battery trough a 30amp inline fuse and some thick gauge wire seems to be helpful to get better and more stable voltage, so if the varadero is wired up the same way then there's a chance doing your own wiring might be better than the standard plugs anyway.