Regulator Woes

[Kiwi_Roy]

Well I finally got the regulator back together, hooked it up and it works great. The battery came straight up to 13.8 Volts from around 11 and it puts out over 10 Amps at 1000 RPM, no sign of any hot spots.

I will test it for a few days then pot it with some sort of epoxy or silicone.

It was a bit of an exercise but I learned a lot in the process, hopefully I will be able to pass on some of what I learned.

Time to celebrate

 

[The Monkey]

Excellent Roy! as I mentioned before we had great luck with Sikaflex 241,291? on the boats keeping the electrics dry below the waterline in the salt water environment. Real curious on how the new reg works. Congrats and good luck!

[raz]

an 250 enduro on which a feller in his 60's did stop and ask if all was well. Nice to see a human out here.

He just hoped you were about to open that Tequila bottle

 

@Roy: Great! You saved a hundred bucks there. I need to check out my old one, I never tried measuring for diodes between red and yellows, for a starter.

[Kiwi_Roy]

Excellent Roy! as I mentioned before we had great luck with Sikaflex 241,291? on the boats keeping the electrics dry below the waterline in the salt water environment. Real curious on how the new reg works. Congrats and good luck!

Thanks, the 291 sounds ideal, I'll pick a tube up. I will try to stay out of salt water though, I get into enough trouble on the road.

 

Update May 31,

The regulator seems to be fine now, I will re-pot it this week.

Before I fixed it I had ordered a bunch of heavy duty parts to build my own regulator so I will carry on with that project as time permits. I think the Ducati one is quite good but some of the parts seem a little weak. I tested the alternator and found it puts out over 25 Amps although I suspect it would soon burn out but I figure the regulator should at least be capable of handling whatever the alternator can throw at it.

My regulator will use similar components (diodes & Silicon Controlled Rectifiers) only higher rated and arranged differently.

 

Update June 16th

 

After fixing the regulator I was still having battery problems. It turned out the battery I bought new last November was faulty and replaced under warranty.

Now with the repaired regulator and replacement battery my problems hopefully are a thing of the past.

As time permits I will carry on with my regulator design project using one of the old housings Slavomir so kindly sent and 50 Amp main components.

[raz]

I need to check out my old one, I never tried measuring for diodes between red and yellows, for a starter.

OK, today I started working on my old one as there is a fellow needing it. Sure enough, I could measure a 400mV drop diode between one yellow and red, but not from the other yellow. This is just what was expected given the sympthoms (too weak at low revs).

 

I definitely needed to heat the potting, it was like cheramics! I heated using a hot air gun set at 200°C for more than half an hour (I think the resulting temp was less than 100°C, it didn't hurt much touching it). This made the potting soft enough I could cut it and pry it away.

 

Funny enough, now it measures out good. Possibly all the heating made things better. I won't trust that of course, I need to inspect the diodes.

 

Now leads are unsoldered but I'm gonna study your PDF's before I proceed. Can I really pry the PCB out without damaging components? I think I need to heat it for an hour again before trying that. Or put the cooling fins in boiled water.

[Kiwi_Roy]

Can I really pry the PCB out without damaging components? I think I need to heat it for an hour again before trying that. Or put the cooling fins in boiled water.

I scratched around under the board as best I could before prying off, I assume you also have the SCRs unsoldered, the transistor in the middle of the board is not fixed to the case but it usually stays behind,

The other thing is a jumper wire that goes corner to corner, (yellow wire to diode) it will stay behind if you unsolder it.

One of your diodes has let go for sure, heating it up must have made it touch again, won't stay that way. They are like a little hockey puck with two leads soldered on. Once you have the leads unsoldered from the circuit board see if one is free to move.

If you don't think it's going to come out the other option is external diodes, I would use one of those potted bridge rectifiers and bolt it to something.

If you need any parts let me know I have salvaged some you can have no cost.

 

Perhaps instead of taking the whole circuit board out you could break the corner out and just connect back to the diodes with short jumpers, might save some time.

Roy

[raz]

Thanks, I'll give it a try tonight. Cutting that corner of the PCB may be a very good idea. There's no tracks on the other side, right?

 

I definitely needed to heat the potting, it was like cheramics! I heated using a hot air gun set at 200°C for more than half an hour (I think the resulting temp was less than 100°C, it didn't hurt much touching it). This made the potting soft enough I could cut it and pry it away.

OK, now I've also got two busted ones with that green rubber-like potting. Much easier. There is no way I can lift the PCB from the one with black potting without breaking it to very small pieces of debris but I should be able to get to the diodes or fit one diode externally.

 

Another question as I'm a bit rusty (or just plain stupid): The charging system is 350W, or "14V 25A". That means I can use 25A diodes, right? (ignoring margins for the sake of discussion)?

 

Edit:

All three busted regulators I have has the same part no, 343637. Except for the potting there is no difference I can see except the voltage trim resistor happened to be 2K7 on both newer ones while the oldest one had a 2K4. That one was damaged so I'm replacing it with a 2K7 too, hoping for a slight voltage boost.

[Kiwi_Roy]

Thanks, I'll give it a try tonight. Cutting that corner of the PCB may be a very good idea. There's no tracks on the other side, right?

 

I definitely needed to heat the potting, it was like cheramics! I heated using a hot air gun set at 200°C for more than half an hour (I think the resulting temp was less than 100°C, it didn't hurt much touching it). This made the potting soft enough I could cut it and pry it away.

OK, now I've also got two busted ones with that green rubber-like potting. Much easier. There is no way I can lift the PCB from the one with black potting without breaking it to very small pieces of debris but I should be able to get to the diodes or fit one diode externally.

 

Another question as I'm a bit rusty (or just plain stupid): The charging system is 350W, or "14V 25A". That means I can use 25A diodes, right? (ignoring margins for the sake of discussion)?

 

Edit:

All three busted regulators I have has the same part no, 343637. Except for the potting there is no difference I can see except the voltage trim resistor happened to be 2K7 on both newer ones while the oldest one had a 2K4. That one was damaged so I'm replacing it with a 2K7 too, hoping for a slight voltage boost.

Update....

I had a look at the circuit board, there are several components that would be destroyed by cutting the board, i think the only option you have if you can't get the board out is to add external diodes. I think a 25 amp diode is more than enough, the normal current is much less. the problem is keeping the diode cool thats why I like the square potted bridge you can just bolt that on to a chunk of metal somewhere and not have to worry about insulating it from the chassis. Adding external diodes also eliminates the possibility of screwing up the board.

Re the trim resistor, I used a trim pot in series with a resistor but I wound up having to turn it opposite to the way I figured so i either screwed up on the wiring or miss-understood how it works. I measured the resistance tonight and it works out More resistance = More battery voltage

Regulator External Diodes.pdf

[raz]

Thanks. Is there an easy way to measure an SCR for good/bad? I don't see normal diode test readings on any of them (not even ones known good). Two of my busted regulators had the alleged fault of giving 17-18 volts of charge but I can't see anything wrong and all resistor/diode/path tests show good. I would have guessed a busted SCR would measure out like a four inch nail but they don't seem to do that. Maybe I need to connect AC to those regulators and do an active test.

[Kiwi_Roy]

Thanks. Is there an easy way to measure an SCR for good/bad? I don't see normal diode test readings on any of them (not even ones known good). Two of my busted regulators had the alleged fault of giving 17-18 volts of charge but I can't see anything wrong and all resistor/diode/path tests show good. I would have guessed a busted SCR would measure out like a four inch nail but they don't seem to do that. Maybe I need to connect AC to those regulators and do an active test.

Yes the ones I have seen are usually shorted out but I haven't found a bad one in the regulator yet, they are a pretty rugged device.

I test SCRs out using my bench DC power supply set at about 1 amp but you need them out for that. I think you should be able to see the Cathode Gate junction with a diode tester, I will try that tomorrow.

Yes an active test using a transformer is an excellent idea, you could put it in place of the alternator and let it charge a battery that should work 12 - 16 Volt or even a transformer 12 - 24 V with a lamp in series to limit the current, The lamp would start to dim approaching the set voltage as the regulator skips half cycles.

I couldn't find one the right voltage in my junk. Come to think of it a simple battery charger might do it. connect it one way to check one Diode SCR pair then flip the leads to check the other pair. Or you could open it up and connect to the transformer, even better.

Roy

[luhbo]

... Two of my busted regulators had the alleged fault of giving 17-18 volts of charge but I can't see anything wrong and all resistor/diode/path tests show good....

 

That's reasonable. If you get 18V then all components work as they should, besides the regulator circuit wich obviously fails to open the rectifier at 14/15V. The internals get damp after some years, salt and other nasty things get in as well and as a result migration often starts bridging parts and even wires.

 

Putting mine into the kitchen oven at 120°C for some hours cured the 17V problem. Probably temporarily, but for this summer it works.

 

Hubert

[raz]

... Two of my busted regulators had the alleged fault of giving 17-18 volts of charge but I can't see anything wrong and all resistor/diode/path tests show good....

 

That's reasonable. If you get 18V then all components work as they should, besides the regulator circuit wich obviously fails to open the rectifier at 14/15V. The internals get damp after some years, salt and other nasty things get in as well and as a result migration often starts bridging parts and even wires.

 

Putting mine into the kitchen oven at 120°C for some hours cured the 17V problem. Probably temporarily, but for this summer it works.

 

Hubert

I can't see how the potting could fail to keep moisture out (looked really tight everywhere and no cracks), but maybe you are right. I'll aim for some active tests.

 

BTW I tried re-soldering most components on the PCB's in case there was hard-to-spot soldering faults. My 40W Weller iron is far too weak for the diodes and external wire solders. I need to buy a cheap-ish heavier iron for them. Not sure how much power is needed. I remember my dad had a huge soldering iron that was probably capable of soldering tin cans, that one would have come handy

[raz]

Come to think of it a simple battery charger might do it. connect it one way to check one Diode SCR pair then flip the leads to check the other pair.

Do you mean I connect 15VDC should give nothing? And then reverse poles on the input. I guess that should work. With a variable supply I could even spot the switch point. No wait, I could put the reference wire to a voltage divider potentiometer! And use a 15VDC or higher source. This might be a plan.

 

Maybe it's better just hooking it up properly to my bike though. This will test all of it at once. It's just that I would need to pull fairing and tank - and then mount the tank again for a test run, and then remove it again, and...

[docc]

. . . I remember my dad had a huge soldering iron that was probably capable of soldering tin cans, that one would have come handy

 

Hey! Who's bike you callin' a "tin can?"

[raz]

Just my own... cause your bikes don't even have a metal tank!