Can anybody give an idiots guide to alternators?

[Knucklehead]

Hi all, hoping somebody can explain the xmas light show I got after fitting a new alternator today.

Got new alternator from RoughTrax who normally supply decent kit.

First thing I noticed after starting for the first time was all the dash lights lighting up as shown below which I am fairly sure never happened with the previous alternator or they turned off real quick. These now stay on until I give it a bit of a rev and the lights disappear until next time it is started.


I checked the connections to make sure I hadn't forgot to tighten something up.

Using limited knowledge of this stuff, I used a multi-meter that showed both batteries are around 12.7v with engine off. Then with engine at tick over with no load shows about 14.2v which drops down to 12.6v with lights on and 12.23v with lights, heater, radio etc.. on.

Revving up to 1200rpm ish the alternator seems to be doing the right thing kicking out 14.05v loaded.

Surely the alternator under load at tick over needs to be kicking out more than the normal 12.7v battery voltage shown with engine off ? The batteries are getting on a bit but the old alternator didn't have the new dash light show so don't think its them.

Any thoughts much appreciated before I point my finger at the new alternator.

Cheers
Dave.

 

[stumog]

Bend the connectors a bit as they may well not be a good enough connection.

 

[StarCruiser]

As Stu says, make sure the multiplug on the back of the alternator is connecting well. Clean it up if you can and if possible (and it may be too difficult to get at them) give the contacts a very light squeeze. You could try wiggling the plug with the meter connected. Somehow I suspect this may not cure the problem as it looks like the regulator isn't regulating properly, which can of course be a result of bad connections on the multiplug.

 

[Knucklehead]

Yeah had tried giving the plug a wiggle and push but seems fairly well connected.
I'll pull it off again tomorrow and double check it again.

Seems odd only shows dash warning lights on start up.
Went for a long drive with all electrics blasting and all warning lights were off as normal with the volt gauge in it's usual spot. You would think with a plug connection issue it would show up more than just start up.

Might just fit the old one back on as gave me less grief apart from noisy bearings!

Dave.

 

[StarCruiser]

You could always replace the bearings Dave, they're not difficult to do.

Robson and Francis would possibly help on the problem with the replacement alternator. I would have pointed you their way for the new unit but I expect RT will be nothing but spot on with their customer service.

 

[Knucklehead]

I am planning to rebuild the unit that came off as is Toyo part, can't imagine its the original one but who knows.

Bought the roughtrax one as are fairly cheap and needed to keep the car on the road.
My great plan might just bite me on the arse. Hopefully find something simple in the light of day but reckon its a dodgy unit i've been sent.

 

[Towpack]

As has been said, your issue is typical of a bad connection. Take the plug off and clean the contacts best you can and use some Servisol switch cleaner or similar. The female contacts can be tightened with careful use of some needle nose pliers.

 

[Knucklehead]

Thanks. Will grab some contact cleaner today and give the connections a good going over as suggested.

Baffled how it seems to be charging fine when driving but dies a death at tick over. Then again electrical stuff has always baffled my little brain.

 

[frank rabbets]

It's fiddly but you can take the plug to pieces and clean the contacts. if you look at the opening of the plug you'll see a 3 slots at the edges of the 3 openings and if you put a needle in each one in turn and pull the wires in turn they easily slide out. Each wire has a rubber seal on it which slides in to the plug body when you push it back in.

I would think if you've already wiggled the plug it may well be a faulty unit.

 

[flint]

Deoxit D5 has worked well for me as a contact cleaner / restorer. It's a bit pricey, but it goes a long way.

 

[Knucklehead]

Cheers for pointers. Patiently waiting outside motor factors for them to open for spray. Will make sure all contacts are spotless and tight and try again.

If still issues I’m going to pull the new alternator and put the old one back on. If no Xmas tree lights as I suspect will be the case, the supplier can expect a very angry call in the morning.

 

[frank rabbets]

Lets hope they don't say as you've used it it will have to go back under warranty for inspection. That's happened to me before. Your argument must be that it was supplied faulty out of the box therefore you're entitled to money back or replacement. That's UK law anyway. Other than that I hope Brexit doesn't queer your pitch lol.

 

[uHu]

There is one more possibilty, the grounding cable from engine to chassis/body. If it is anything like on the hdj100, there is one just under the alternator, on the engine mount. Otherwise, all seems to be covered in this thread.

 

[Knucklehead]

Can anybody recommend a good replacement alternator supplier?

Bit of a wasted trip this morning. Connections now spotlessly clean and tight fitting but still xmas light display.
Can't see there being earthing problems and had no issues like this with the old alternator that came off yesterday.

Managed to borrow one of those traffic light battery/alternator meters. Not high tech kit but shows well enough at tick over with lights, heater etc.. the alternator is doing nowt and my batteries are happily discharging themselves. Give it some rev and it kicks into life.

Bout to email roughtrax and see what they suggest regarding replacement or refund.
Not really sure that keen to try another one.

Anyhow thanks for advice. I'll be a wizz at changing out alternators when finished.

Dave.

 

[StarCruiser]

Can anybody recommend a good replacement alternator supplier?

Bit of a wasted trip this morning. Connections now spotlessly clean and tight fitting but still xmas light display.
Can't see there being earthing problems and had no issues like this with the old alternator that came off yesterday.

Managed to borrow one of those traffic light battery/alternator meters. Not high tech kit but shows well enough at tick over with lights, heater etc.. the alternator is doing nowt and my batteries are happily discharging themselves. Give it some rev and it kicks into life.

Bout to email roughtrax and see what they suggest regarding replacement or refund.
Not really sure that keen to try another one.

Anyhow thanks for advice. I'll be a wizz at changing out alternators when finished.

Dave.

Give Mike at Robson and Francis a call re a replacement unit or possibly parts to re Con your old unit. 0207 733 2353 Not sure what time Mike gets in, may be later on a Monday as he does a collection round. You won't get better service or knowledge, they are the remanufacturers for many of the suppliers. They also source new units.

 

[Knucklehead]

Many thanks for the contact.

I’ve emailed roughtrax to see options regard replacement or refund. Refund would be better as don’t have great confidence in these units but only fair give them chance to rectify.

Cheers
Dave.

 

[frank rabbets]

You are entitled to full refund. It's not their decision to make. They may act ignorantly but they will defo be aware of this as it won't be the first time it's happened and I expect they go on training courses if they are a good firm. I've talked to Robson and Francis in the past and they really Knew their "stuff".

 

[t1pper]

My understanding is that an alternator has to spin at a set minimum speed before it starts charging had it several times before with different vehicles a quick blip on the throttle turns it on once it's charging the RPM can get very low before the light comes back on.
Is your tickover very low or the new alternator pulley slightly larger meaning the RPM of the alternator are a bit slow.

 

[Towpack]

An alternator will charge the battery at tick over by delivering full, or close to, full voltage with no other load but applying a load such as lights, heaters etc will drag the voltage down until it spins faster. This seems to be what's happening here.

 

[Knucklehead]

Bit baffled by all this. None of the issues I am having now where present with the old alternator. No dash light warnings on start up or discharging batteries under load at tick over. The tick over for my 1HDT motor seems correct and hasn't changed in all the years I've owned it so don't think that is an issue.

I have forwarded some images to the manufacturer of the alternator sleeping at tick over when there is a load present and my batteries discharging themselves. For my thinking even at tick over the alternator should be stepping up when there is a load or the batteries take the hit.

Was not a pleasant feeling this morning in traffic jams not wishing to use any heaters and the likes.
The images below show the output at tick over with lights, heater, radio. Not the greatest alternator meter around but shows good enough the batteries are in melt down.