Alternator conversion consequences

[anotheralan]

Hi

I'm converting to an alternator and am interested in the views of members on the point of an Ammeter or Voltmeter. Purists need not respond on the blasphemy I have just uttered

The only benefits I can think of are that if the alternator fails I could watch my battery die, provided I happen to notice before the lights dim or I come to a standstill. Also I guess if I fit a voltmeter instead I could see the battery condition when I switch on before listening to the starter labouring, or I could check the battery condition the night before a planned trip.

Would a clock be more use?

Discuss

Alan

[BlueTR3A-5EKT]

For the non purist who has added a cigarette lighter socket to power their accessories.

 

Buy this or similar and plug it into the accessory socket and find out your battery/system voltage. It saved me when my alternator went duff, I noted the drop in voltage compared to what I had always observed. Test it in your Eurobox to find out what voltage your alternator ought to be giving.

 

http://www.ebay.co.uk/itm/Hakkin-2-in1-Car-12V-Cigarette-Lighter-Plug-LED-Dual-Digital-Voltmeter-Tester-/112266184734?hash=item1a2396081e:g:uX8AAOSw241Ydwg-

 

Keep the ammeter in place. I ran an additional fat electricity wire from the alternator to the battery terminal side of the starter solenoid, which does cause odd readings on the ammeter. ie no 'charge' in regular use.

 

Peter W

Edited May 17, 2017 by BlueTR3A-5EKT

[anotheralan]

Thanks Peter

I suppose when and if the alternator fails you would see a big negative on the Ammeter if it is still in place.

 

What happens if the ammeter fails or disconnects while the Alt still running? Good argument for your more direct connection from Alt to Battery and the voltage warning gadget as backup.

 

I like the gadget. I too have a cig lighter outlet which i put in for TomTom. When I looked at your link there were some alternatives on offer including one with a USB socket as well.

 

http://www.ebay.co.uk/itm/3-in1-Car-Digital-Voltmeter-Thermometer-12-24V-Cigarette-Lighter-USB-Car-Charger/302269605359?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D43781%26meid%3Dbfde116baa2f4ccb94ca8e37919156a2%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D112266184734

 

Alan

[peejay4A]

There's next to nothing in an ammeter to fail. Even if the single turn winding got hot enough to melt the solder I reckon the rest of the loom would be on fire already.

[Lebro]

In my humble opinion, to change to alternator use you only need to change the following:

 

If +ve earth, change to -ve (reverse ammeter connections, battery connections, & coil connections)

 

Add a second heavy wire from Alternator ouput to connections mentioned below (or change existing one for a heavier guage)

 

Replace regulator with some new connections (details can be provided, but have been on the forum before - many times)

or modify the regulator to give these required connections.

 

That's it. Existing ammeter will be fine.

 

Bob.

Edited May 18, 2017 by Lebro

[Guest]

Voltmeter - all the way.

 

First: a modern alternator, often a Nippon Denso, doesn't fail. It's Suzuki/Kubota first choice. These companies know what they pick from the shelf. You don't need an A-meter for that.

Second: when using an A-meter, there's a lot of current running within an inch distance away from all sorts of metal parts... Granted, the current going through the wires of a V-meter is enough to melt the cables as well, but it's less 'disturbing'

 

I opted for a V-meter (thanks to Stuart I found a period correct one for my 59 3A) and never looked back.

 

Menno

[littlejim]

For the non purist who has added a cigarette lighter socket to power their accessories.

 

Buy this or similar and plug it into the accessory socket and find out your battery/system voltage. It saved me when my alternator went duff, I noted the drop in voltage compared to what I had always observed. Test it in your Eurobox to find out what voltage your alternator ought to be giving.

 

http://www.ebay.co.uk/itm/Hakkin-2-in1-Car-12V-Cigarette-Lighter-Plug-LED-Dual-Digital-Voltmeter-Tester-/112266184734?hash=item1a2396081e:g:uX8AAOSw241Ydwg-

 

Keep the ammeter in place. I ran an additional fat electricity wire from the alternator to the battery terminal side of the starter solenoid, which does cause odd readings on the ammeter. ie no 'charge' in regular use.

 

Peter W

Good one Peter!

Must see if you can buy them over/down here.

[anotheralan]

Voltmeter - all the way.

 

First: a modern alternator, often a Nippon Denso, doesn't fail. It's Suzuki/Kubota first choice. These companies know what they pick from the shelf. You don't need an A-meter for that.

Second: when using an A-meter, there's a lot of current running within an inch distance away from all sorts of metal parts... Granted, the current going through the wires of a V-meter is enough to melt the cables as well, but it's less 'disturbing'

 

I opted for a V-meter (thanks to Stuart I found a period correct one for my 59 3A) and never looked back.

 

Menno

I can see the Vmeter gives you battery condition and surely the voltmeter is a high resistance device and therefore passes very little current, in its favour, but it is still necessary to take a current supply to the potentially constant draws, i.e. lights/wipers/coil/fan, via the ignition, which is also near the metal bits of the dash.

 

Don't mind me, i'm only displaying my indecision.

 

Thanks to all for comments. Make my mind up time.

 

Alan

[ianc]

Alan is correct – the current flow to a voltmeter is miniscule.

 

With an alternator installed, the only occasions when there will be a large current flow through the ammeter will be:

1 – immediately after starting the engine and, unless the engine was proving a pig to start, this high current will last a very short time (usually down to almost zero by the time I have driven a mile).

2 – if the engine is NOT running and ALL the electrics are switched on (lights, wipers, fan, heater, refrigerator, cooker, toaster, heated seats etc).

 

I have an alternator rated at a modest 35 amps, but even just after starting the engine, I have never seen the ammeter show a charge of 30 amps.

 

In TR Action 296 (March 2017), I suggested modifications to the wiring which would both increase the potency of the headlamps and reduce the current flow through the ammeter and the lighting switch.

 

In TR Action 118, I described fitment of an alternator to my car, and this article can be found in Section J4 of the Technicalities CD. More recently, in TR Action 248 (March 2011), James Christie and I described fitment of an alternator from a Moss kit, and we illustrated ed the use of ammeter or voltmeter.

 

Ian Cornish

[anotheralan]

Alan is correct – the current flow to a voltmeter is miniscule.

 

With an alternator installed, the only occasions when there will be a large current flow through the ammeter will be:

1 – immediately after starting the engine and, unless the engine was proving a pig to start, this high current will last a very short time (usually down to almost zero by the time I have driven a mile).

2 – if the engine is NOT running and ALL the electrics are switched on (lights, wipers, fan, heater, refrigerator, cooker, toaster, heated seats etc).

 

I have an alternator rated at a modest 35 amps, but even just after starting the engine, I have never seen the ammeter show a charge of 30 amps.

 

In TR Action 296 (March 2017), I suggested modifications to the wiring which would both increase the potency of the headlamps and reduce the current flow through the ammeter and the lighting switch.

 

In TR Action 118, I described fitment of an alternator to my car, and this article can be found in Section J4 of the Technicalities CD. More recently, in TR Action 248 (March 2011), James Christie and I described fitment of an alternator from a Moss kit, and we illustrated ed the use of ammeter or voltmeter.

 

Ian Cornish

Thanks Ian. I have read J4 and very helpful it has been. Is there an accessible archive of back issues of TR Action? I have the March 2017 copy but am interested in TR Action 248.

 

At the moment I am trying to establish how the adjuster strap is provided to my new L/H LRA101. I am getting the alternative mounting bracket from Revington and will look at their strap also. Just looking at the initial offering up of the alternator on the pillar the plane of the front of the alt does not obviously line up with anything on the engine, and certainly not the tapping for the dynamo strap. The lower bolt on the pump casing looks the best angle but is not in plane. Where/how did you solve this.

 

Alan

[jean]

On my 3 I have done the same as mentioned by Peter W... a big fat extra wire from the alternator to the solenoid, if it's the same size as the Original it will divide the current by 2.

 

On my 6 I have fitted a shunt on the A meter as I have fitted a more powerfull alternator for the EFI.

But on the other side I fully agree with the V meter modification.

[ianc]

Alan, My LRA101 uses Revington's bottom bracket (a modified version of the original and the first one he had made), but at the top, it uses the original dynamo adjustment bracket which, as far as I can recall, has not been modified and is mounted as usual. I think that when you have the bottom bracket installed, everything should work out - call Neil, if not!

From what Wayne has posted recently, I believe that ALL TR Actions are now available on-line through the club's website, but I haven't tried this.

I loaded the CD, containing numbers 1-200, onto my hard disc, which saves hunting for the CD (small, and easily mislaid)!

If you want the article from 248, PM me with your home email address and I'll send an MS-Word copy.

Ian Cornish

Edited May 19, 2017 by ianc

[iain]

.......Or use the "Members Section" to search for Issue 248 or March 2011 of TRaction...its there in all its glory. (Search term March 2011 brought it up easily)

 

Iain

[anotheralan]

On my 3 I have done the same as mentioned by Peter W... a big fat extra wire from the alternator to the solenoid, if it's the same size as the Original it will divide the current by 2.

 

On my 6 I have fitted a shunt on the A meter as I have fitted a more powerfull alternator for the EFI.

But on the other side I fully agree with the V meter modification.

Thanks Jean. I too had considered a direct connection to battery in parallel with A meter, but then I thought each should be able to cope, in terms of current capacity, on their own (in case of accidental disconnection of one). Even so the current will not be halved in each unless the resistance of each parallel circuit is equal to the other. Same guage but different lengths of wire will give differing resistances pro-rata the lengths of each parallel circuit. If as I would expect the A meter circuit is much longer of the two then relatively little current would choose to flow via the ammeter.

All things considered I have decided to dispense with the A meter altogether and substitute a V meter in the hole to give me condition. Alternator directly connected to the battery and the light and ign switches using new 39amp wire.

Unless of course someone cuts my legs off

[anotheralan]

Alan, My LRA101 uses Revington's bottom bracket (a modified version of the original and the first one he had made), but at the top, it uses the original dynamo adjustment bracket which, as far as I can recall, has not been modified and is mounted as usual. I think that when you have the bottom bracket installed, everything should work out - call Neil, if not!

From what Wayne has posted recently, I believe that ALL TR Actions are now available on-line through the club's website, but I haven't tried this.

I loaded the CD, containing numbers 1-200, onto my hard disc, which saves hunting for the CD (small, and easily mislaid)!

If you want the article from 248, PM me with your home email address and I'll send an MS-Word copy.

Ian Cornish

Thanks Ian

Just bought a revington bracket and his adjustment strap. I don't live far from Middlezoy so was able to check it out visually and dimensionally. A TR2 in the workshop had the adjuster mounting set up, which requires replacing one of the pump casing bolts with a stud to facilitate a slightly forward plane. The attachment tapping for the Dynamo really is not in the right place to tension the belt.

Also found TR248 article. Not the most intuitive structure of web pages for this crucial resource. Could do with a more visible link nearer te surface of the site rather than burying it.

Cheers

[anotheralan]

.......Or use the "Members Section" to search for Issue 248 or March 2011 of TRaction...its there in all its glory. (Search term March 2011 brought it up easily)

 

Iain

Got it. Thanks

[tthomson]

Alternators have three stator windings that supply the electrical output. The chance of all three failing is extremely remote. The Stator windings do not go through a commutator or carbon brushes, so they can supply a lot more current than a dynamo.

 

So the Ammeter will be redundant, but because alternators have voltage regulating diodes that can fail, a voltmeter will be very useful to let you know that the correct voltage is being supplied. A voltmeter is connected across the battery, and only needs thin wires.

 

As mentioned in one of the earlier posts getting a suitable voltmeter is relatively easy - Speedy Cables have a whole range of meters in a compatible form.

 

Good luck

 

TT

[RobH]

Sorry TT but I beg to differ. An ammeter is never redundant as unlike a voltmeter it actually tells you where the current is going. A voltmeter will tell you that a voltage is there but it won't tell you whether it is charging the battery. Similarly it won't tell you what is being pulled from the battery in the way of discharge.

[DaveR]

1+ RobH.

 

The whole point of the ammeter was to allow you to manage the electrical system. i.e If you were stuck in traffic with all the electrical kit on and the engine on tick over the ammeter showed a large discharge from the battery. This basically pointed out that you should switch a few things off otherwise the battery would soon be flat.

 

A voltmeter will show a voltage increase if the battery is being charged, but not the charge rate.

 

Dave

[tthomson]

Point taken Rob.

 

I was working on the basis of making a selection between the two meters, but it is preferable to have both. They do two different things and both are of value.

 

TT

[anotheralan]

I accept all your views as having validity. However, I have to come back to the reality that I am converting so that I can generate sufficient current to cope with the maximum demand and not be trying to manage an excess demand of circumstance by turning stuff off. So if I still had a problem after conversion it would be that I had not provided a large enough alternator - or it had failed in which case I would be in trouble and need a new one.

My personal take is that I value knowing the battery condition at startup without having to get the multimeter out, if there were a current leak for instance, and when running there should not be a problem, but if there were I would see the voltage dropping off below normal. Surely in that scenario I can still turn off demand where safe but it may not be the fix needed.

I guess we have all said our piece and I know I have found it helpful, but this thread has probably run its course. Thanks to all, think positive and may the charge be with you.

Alan