Why MHs should have Digital Voltmeter's in the Cab

This is a recent development...



...Ah...better fix that...one of these days..

Ps. This voltmeter is junk, it's 150mV high of calibration, no passive filtering so makes the radio ring, and takes up my only cig. lighter port in the cab. Not as bad as it looks then..only ~15.5v at the battery
Still though this is useful information. Think of it like a temperature gauge never does much but when you need it you need it.

Aidan_M_M

Thing is though Liam, the majority of MH owners drive Ducatos , and alternator failure is almost unheard of , unless they get jump started and the jump leads get connected wrong.

Aidan_M_M

What's yer secret I get about one a year.
People not loading them to 80% max rating?

Hrmm let me check my problem solving flow-chart.

Aidan_M_M wrote: »

unless they get jump started and the jump leads get connected wrong.

I would've expected 24v to fry the ECU long before the alternator. Too many diodes see.

Given the amount of blown head gaskets you see wouldya remove the temp. guage?

Aidan_M_M

Just good quality alternators from Magneti Marelli or Bosch, with proper multi V belts on most since 94. And with a good output.
If you're doing one a year there has to be a weak link in the chain... Either poor quality parts when rebuilding, improper reassembly, something wrong with the way the batteries are pulling from it, or bad wiring. And knowing yourself I'm assuming it's none of those... So which suggests you need a higher output alternator.

I've never had a Ducato blow a head gasket.

Aidan_M_M

Aidan_M_M wrote: »

which suggests you need a higher output alternator.

Or two ...I reckon it'd save fuel...less coil resistance.

Bosch 55A.

Reconditioned last year by professional after slip rings wore out, tested in house to flash full output. Brushes every year. V-belt 6 month's old, new tensioner. Contacts all shiney. Seasonal regulator rotation.
Had a brush pop out and run short circuit for 50 miles there a few month's back that blew a track off the regulator PCB. Fixed since but not tested. Obviously that regulator in photo is toast, already swapped.

Aidan_M_M wrote: »

...something wrong with the way the batteries are pulling from it

Alternator -> battery -> auto-electrics & solar controller -> more batteries -> loadsov loads...eh..maybe.

Point being if I hadn't spent €3 on this gizmo in a matter of month's I'd have no electrolyte in my starter battery. No battery warning light illumination for this condition. Dunno how those modern machines do things though. Plus I like to know cranking voltage drop and parallel loading drop.

moodrater

Sir Liamalot wrote: »

Or two ...I reckon it'd save fuel...less coil resistance.

Bosch 55A.

Reconditioned last year by professional after slip rings wore out, tested in house to flash full output. Brushes every year. V-belt 6 month's old, new tensioner. Contacts all shiney. Seasonal regulator rotation.
Had a brush pop out and run short circuit for 50 miles there a few month's back that blew a track off the regulator PCB. Fixed since but not tested. Obviously that regulator in photo is toast, already swapped.



Alternator -> battery -> auto-electrics & solar controller -> more batteries -> loadsov loads...eh..maybe.

55A theres the explaination

If its eating brushes at that rate I'd wonder did your professional mill the commutator.

Every car I've ever owned has been driven to at least 120k miles in my ownership, wifes passat has nearly 220k miles and I've never changed or touched an alternator. Put a bullet in that yoke.

It only eats one brush at a time and it's a different one this time since last recon.
By professional I mean a person who is paid to do a thing...I think most people assume they're experts. :pac:

Yeah you're right I should put it down but don't fancy making a new loom tbh.
I've a list as long as my arm on how things should be in that machine, priorities M.

Three days now fighting with a starter motor, had another "professional" recondition it, then made him re-recondition it because it was still fecked.
Alternator can wait til the weather improves...when I'll not be bothered cos the PV will be kicking bottom.
Next job is the fuel sender and tank...haveta go in from underneath too...some smart chap put a conversion on top of the access hatch. :rolleyes:

moodrater

Sir Liamalot wrote: »

..some smart chap put a conversion on top of the access hatch. :rolleyes:

hard to make a camper without covering something

Best rule of thumb is design it to remove it again. My kitchen unit is a nightmare, nothing modular about it.

I may be reconsidering shooting that alternator...except it does make running it through a 45A solar controller more difficult.

I've another regulator in now and when the battery is charged and unloaded it's still kicking out 15.5V. Any ideas what it might be? I'm going to splash out on a new reg. before I autopsy it. Recently replaced the battery so it's possible the symptom is old but the older battery was never "fully charged" to be an issue.

What are the potential hazards of driving with the brushes shorted? I thought no excitation = no problem.
Just wondering if the coil packs might be damaged.

It lifted a track between a transistor collector (datasheet) and a diode on the regulator. See the jumper bodge below.

It only seems to be over-voltage when the engine idles.

Aidan_M_M

Sir Liamalot wrote: »

It only seems to be over-voltage when the engine idles.

Would an Audi A4 ALT be any use to you?

Anything like this?

Part no. 0120 489 331 332

Nekarsulm

Sir Liamalot, I have just spotted your problem solving flow chart. I particularly like the closed loop between "Can you blame someone else" and "You poor Bastard" !!

gctest50

Sir Liamalot wrote: »

Anything like this?
....

a better alternator instead maybe ? ( see attached salesy stuff )

little trucks have ones with two internal fans and external regulator

https://www.google.ie/search?q=mitsubishi+isuzu+12v+truck+alternator

Aidan_M_M

Sir Liamalot wrote: »

Anything like this?

Part no. 0120 489 331 332

Sorry Liam, no. How about a mk2 Golf one?

Ah think I'll be alright for a bit T. thanks though. May get back to you if I can't fix this.
It's fine if I turn the dipped lights on. I have a selection of alternators myself although none of them are a straight swap.

gctest50

gctest50 wrote: »

a better alternator instead maybe ? ( see attached salesy stuff )

little trucks have ones with two internal fans and external regulator

Oops I skipped a page didn't see this.
Yeah thought about it but it's a big job, may still to it although I'm tempted to put a second one in there if I'm going to that sortov bother.

The wires off my present will only take about 60A through a house....not through an engine bay so they'll have to be upgraded; not a massive job but finicky. Then I also have to current limit the input to my solar controller or go back to CV charging for my deep cycles.
I've been relying on it's crapness to self-regulate really.

moodrater

Sir Liamalot wrote: »

Anything like this?

Part no. 0120 489 331 332

That looks like the same dimensions as the old eclass, it should be really easy to find a 120A alternator, pulley might be a slightly different diamter. Some of those had 180A or more, a second battery, 220V power and a natty split charge system with a colossal relay. So if you're lucky enough to find an exec spec model in the scrap yard you mightend up bringing home more toys :pac:


edit:

115A one here:
http://www.ebay.co.uk/itm/Mercedes-W210-E280-98-96-02-ALTERNATOR-70-115A-0101543202-/400334317954?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3AMercedes-Benz&hash=item5d35c8e982



£20 + parcel motel although I'd spend more than the 2 minutes I spent looking to find a younger cleaner one.

edit:
Looks like the 190A ones were watercooled, not worth the bother.

Water cooled three phase! :pac:
What could possibly go wrong?

moodrater

moodrater wrote: »

That looks like the same dimensions as the old eclass

Doesnay fit though. My pulley shaft is 13mm longer.
Don't fancy making a frankenator...even though I haven't ruled it out.

So what causes overvoltage?
Any way of checking the phases without getting into the diode pack?

It's a no-load condition with 0A (clamp meter) to the starter battery
New starter battery.
Soon as I put a >25W load on it behaves.

Internal short?

I'm starting to wonder if I've just made the electrical system too clean and having a starter battery that actually is 100% charged most of the time is reducing it's ability to voltage clamp the alternator.

3 different regulators now one of them new (spurious, 14.7v rated).
Alternator & battery contacts shiney. +ive bus needs a going over iirc but it's a tad buried.

moodrater

Sir Liamalot wrote: »

Doesnay fit though. My pulley shaft is 23mm longer.

Shafts are different for solid and freewheel pulleys, freewheel screw onto the shaft solid is bolted on. Is the overall pulley position not the same though unless the drawing are wrong 36+56 = 92.

If your d+ is overloaded e.g. driving a relay if so disconnect it and see if it behaves, if it does you can drive the relay via a transistor to unload the d+

25W load is no problem just fit some d+ activated DRLs not naff led one on your era van though

moodrater

Armchair lectricks :pac:
I'll check the D+ & slip ring line resistance and B+ to ground continuity one of these days...

Nah D+ is stock. I'm not a fan of the trad. split charge setup, I think a manual relay is preferable.

Already have 220W DRL on two 110W splits. My headlamps are what's holding my grille together so it was easier install new one's rather than wash the old.
I did eventually get around to cleaning the lenses and restoring the covers the 4th grille rebuild.

Auto-loading it off an ignition switched live is easy enough but just seems like the wrong way to fix it tbh. I know they can go to mental voltages is you run them without a battery to clamp them so maybe it's a design stipulation.

moodrater wrote: »

Shafts are different for solid and freewheel pulleys, freewheel screw onto the shaft solid is bolted on.

What's the difference between a bolt and a screw then? Mine's nutted on I think and if I was to guess I'd say solid.

moodrater wrote: »

Is the overall pulley position not the same though unless the drawing are wrong 36+56 = 92.

Seems so, had a digital callipers run from the back of the bolt-hole to the roughly displaced centre of the pulley on mine and it's 105mm give or take...no amount of eyeballing was taking 13mm all the same, and that's running true to the crank pulley.

For £20 it'd make a good bicycle dynamo worst case scenario but if it's a wiring issue I'd rather suss it first.

moodrater

RE: overvoltage
There'd be a zener in there for overvoltage protection probably. They would be the hottest and first to go.

Re: alternator
Ahh the tinternet looks like the drawing you linked was wrong alright.


I assumed the 20 quid one had a freewheel pulley on it because it was newer fangled is it solid? You can get all different offsets on the pulleys if it is 101mm then something like this fella might do the trick you'd obviously want to do some careful measuring.

http://www.ebay.co.uk/itm/6-GROOVE-SOLID-METAL-ALTERNATOR-PULLEY-60MM-17MM-HOLE-/251538007620?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3a90d56644

moodrater

moodrater wrote: »

RE: overvoltage
There'd be a zener in there for overvoltage protection probably. They would be the hottest and first to go.

I reckon you're onto something there.
That brush short that burnt my reg track coulda popped a zener no probs.
Hrmmm, wouldn't be difficult bodge an external one in somewhere. More elegant than a constant load too.

Wheredya get those schematics? I was having trouble finding them earlier, my google tracker bots need training.

moodrater wrote: »

I assumed the 20 quid one had a freewheel pulley on it because it was newer fangled is it solid?

Dunno, I didn't buy it, the vents look a little charred methinks...might go for the £30 model instead.

moodrater wrote: »

...something like this fella might do the trick

:eek: £17...areya mad!!? Sher ya can get an almost entire alternator fer that!! :eek:

Thanks M.
Plenty there to ponder.

May try a €2 zener, transistor and a 30Watt resistor sortov arrangement possibly first. Hrmm not much to trigger the base with though.

Sir Liamalot wrote: »

No battery warning light illumination for this condition.

PS. the battery light will glow at the 16V mark.

moodrater

moodrater wrote: »

Ahh the tinternet looks like the drawing you linked was wrong alright.

0123 510 066

moodrater

Sir Liamalot wrote: »

0123 510 066

Looks like a decent offset alright. You'd definitely need to get out out the calipers and measure properly. The magnetti marelli drawing for you alternator says 101mm too but the valeo one says 92mm. Maybe be measuring to the first vee rather than center line.

moodrater

Just thinking with your engine does the B measurement even matter does the nut just go directly on the backof the b part?

I'm not sure M. I've yet to see a diagram clearly indicate what B is. I need the full 101mm alright, the boltholes are mated on both sides.

So sticking a petrol alternator in a diesel with a diesel pulley are the gear ratios going to be ok for lower RPM?

moodrater

Sir Liamalot wrote: »

I'm not sure M. I've yet to see a diagram clearly indicate what B is. I need the full 101mm alright, the boltholes are mated on both sides.

So sticking a petrol alternator in a diesel with a diesel pulley are the gear ratios going to be ok for lower RPM?

Theres loads of diesel ones measuring 101mm too 190d, 200d, e200, c200, vito v230, old sprinter all came with the om601 good chance one or more will have similar dimensions.

Too late took a punt on a petrol model before it occurred to me. I imagine the gearing is on the pulley size and seems there's a lot of vehicles running similar alternators on different fuels.

The thick plottens.

Which dya reckon are better? OEM bearings with a few hundred thou miles on or new cheap and nasty Chinese ones? :pac: