old wires new smoke

[scott]

a bit of a melt down behind the dash. the 2 heavy gauged wires going in/out of the ampmeter melted down. this is what happenned. i go by to pick up my rove from badvibes who has been babysitting it for the past seven months. find him in his drive checking and topping off all the fluids. he tells me it hasn't run for about a week or so. he suspects fuel dilivery problem and we diagnose and fix it. backing out of his drive to reward ourselves with burgers and beer discover no cluth no brakes. check the duel hauldrolic resivoirs and twist the m/c feed line cause the resi twist with the cap. get new lines the next day and fix it. drive to the carwash to clean it up a bit. drives great, ampmeter was reading about +10 for the short drive. i leave it with badvibes and the next day it makes it about a block from his house and dies. he puts it back in his drive. i go over today and figure it to be an electrical issue because the glass fuel filter just before the carb has petro in it. now here comes the smokey part. trying to start it smoke starts coming from the dash. we inspect and the melted wires to the ampmeter are the only problem. cut away the burnt parts put on new clips rehook every thing up and still no start and the back of the ampmeter starts smoking and the wires are hot. look in the engine bay for problems and find a loose (very) altenator wire.

could this loose alt wire damage the ampmeter? has anyone every had an ampmeter melt down?

[Tim Smith]

Never had an amp meter melt down but my advice is to get that thing away from badvibes asap! He's obviously been draining the Lucas smoke out of it while you weren't looking.

Sorry, no good advice here. Haven't experienced that one. Yet...

[jopa]

smoke

What alternator are you using...now if you are running the juice through the amp meter is the amperage of the alternator more then the amp guage can handle?...ie GM AC/Delco 60 or 100 amp alternator will fry the lucas 15 amp meter.
Not sure what the amps of a lucas ser 3 type alt produce, but IIRC somewhere around 30 amps...still enough to fry it.
Bypass the amp guage, rewire any melted wires...John

[TedW]

You might need some of this....

Always go with genuine.

[Leslie]

FWIW, the Lucas ACR16 alternator, what was stock on my '72 SIII, produces 34 amps. (I've swapped it for a Delco 10si, now have 63 amps)

Do you have yours as a 3-wire setup? Are you using the sense wire to send to the ampere gauge? Or do you have a 1-wire alternator setup, and are taking the feed to the gauge off of the main line?


I'm suspecting you're getting your alternator to feed way to much power through the gauge instead of just taking a trickle off of it to view.

[greenmeanie]

Ditch the ammeter and replace it with a voltmeter. Its far safer, generally more reliable and tells you more useful information about your charge system.

Cheers
Gregor

[scott]

thanks dudes. especially the advice regarding badvibes. just kidding badvibes, there's no one else i would rather have driving my rover when the dash flames out of control, than you.

the po did the dynamo to alternator conversion using a lucas 35 amp alt. all the wires goining to the now gone voltage regulator are wired together. last year i installed an delco 10si 80 amp and dual batteries. the delco is a 3 wire with the little skinny wire going to the idiot light on the dash, then a short 10 gauge jumping to the main wire, also a 10 gauge that goes to the battery side of the starter relay. my main battery goes just to the starter selenoid with the ground going to the motor. aux battery positive goes to a continuous run selenoid with the negative going to the frame and at this point another ground goes to where the main battery is grounded on the motor. the clump of wires from the now gone voltage regulator go to the continuous run selenoid opposit the secondary battery with the trigger wire going to the fuse that's hot only when the ignition is on. i know with this set up i should put in a toggle switch so that i can manually turn on the continuous run selenoid after the main battery has had a chance to charge after starting, i figure about 10 to 15 minutes. this or one of those exspensive battery isolators do this so that the altenator's internal regulator doesn't sence the need for high ouput and fry old wires.

so i'm guessing the heavy gauge wires going to the ampmeter carry the full output of the 80 amp alt when its internal regulator sences the two batteries needing charged. this is what melted down the old ampmeter, right?

if i go to autozone today and by a volt meter do i just hook it to those two wires that where on the ampmeter?

and i'm guessing i should install a toggle switch for the trigger wire that closes the connection in the continuous run relay, right?

[Terrys]

It doesn't matter if the alternator is rated to put out more than the range of the ammeter UNLESS you are drawing more current than the ammeter range. The Alternator can be rated at 200 amps, but only delivers what the ACTUAL LOAD is. If you're cookibg wires, it's because you have a low resistance short to ground somewhere in that wire, and likely very close to the melted section. All that said, I also agree that the voltmeter in a alternator charging system is more usefull.

[greenmeanie]

if i go to autozone today and by a volt meter do i just hook it to those two wires that where on the ampmeter?

and i'm guessing i should install a toggle switch for the trigger wire that closes the connection in the continuous run relay, right?

Two things:
1. If you convert to a voltmeter install it in parallel with your main electric feed. That way if the meter fails you still have power. It is one of the big advantages of a voltmeter. Rather than typing lots here is a good site with info on alternators and gauges.

http://madelectrical.com/electrical-tech.shtml

2. If you are running dual batteries make sure you have at least some isolator diodes on there with that switch. Using a toggle switch without diode protection can result in a fire. If one battery is drained and you throw the switch the charged battery will drain into the depleted unit until they are equalized. This means an extremely high current which can and will melt wires. It is also bad for the batteries.

I picked up a dual battery controller from Hellroaring and it has been good controlling two Odyssey PC1500s in my 101.

Cheers
Gregor

[scott]

ok, here's my plan to get the rove back on the road today.

-disconnect ampmeter
-find which ampmeter wire goes to the bat and which goes to the alt
-connect the ampmeter to bat wire to a volt meter
-ground voltmeter
-insulate ampmeter to alt wire
-disconnect aux bat selenoid trigger wire (basically go back to a one bat system)
-start shopping for a real aux bat isolator

will this work or cook?

[I Leak Oil]

Just disconnect the two wires from the ammeter and connect them together as the ammeter is wired in series. Wire your new volt meter according to the instructions that come with the new meter.
Jason T.

[badvibes]

Never had an amp meter melt down but my advice is to get that thing away from badvibes asap! He's obviously been draining the Lucas smoke out of it while you weren't looking.

Sorry, no good advice here. Haven't experienced that one. Yet...

Hey I represent that remark! If Lucas is the Prince of Darkness, lately I have been one of his underlings or minions or something. I am become death to Rovers. Guess I'll have to lighten up on that Jack guy.

Jeff

[Tim Smith]

Hey I represent that remark! If Lucas is the Prince of Darkness, lately I have been one of his underlings or minions or something. I am become death to Rovers. Guess I'll have to lighten up on that Jack guy.

Jeff

Well, I may be your antithesis as of late. I now have all the indicators and side lights working... Oh heck! I shouldn't have said that. Mr. Murphy listens in to this forum, doesn't he.

The gauges are still broke! The gauges are still broke! Please don't come to visit Mr. Murphy!!!

[Eric W S]

http://madelectrical.com/electrical-tech.shtml

Great Link! Thanks for posting.

EwS