Removing Ammeter

[little_pete]

When I bought my car it came with a load of dials, I don't like them. Temp and oil are useful yes but I want my glove box back. I'm combining them into one below the dash. They are easy enough to remove. The problem is the Ammeter It has nice thick wires going to it (4: one terminal has one red and one brown with a blue streak, the other has 2 red) Now as I know there's alot of current going through these cables I'm not sure how happy I'd be just connecting them together and calling it a day. They've been taped into the wiring loom and I don't want to undo it all to end up with a mess of wires. Any ideas where to begin with removing the Ammeter? I have an alternator and never had a problem with charge.

My other thought would be to put a battery kill switch in it's place (hidden) and then I can hopefully use this as a sort of immobiliser device? From what I've read the ammeter would be between everything (except the starter) and the battery.

Am I best seeing a auto electrician with all this electricity flying around?

[bmcecosse]

I advise you to keep the ammeter - yes, below the dash is good. Just disconnect the battery while moving it and then reconnect it all as before in the new location. And yes -add a kill switch there too.

[little_pete]

Pretty sure the ammeters wired the wrong way anyway... with the engine off switching on the heater fan and lights only swings the needle a little to the + side I would thought it would go to the negative side? turning on the engine makes no difference. (touch wood the charge on the battery has been fine and it has an alternator fitted and charges fine from almost flat)

[bmcecosse]

So just swap the wires over on the back of the ammeter when you move it!

[little_pete]

Turning on the engine though (and alternator) does not result in a negative flow on the ammeter (wired backwards) so it's somehow not measuring the alternator charge, I thought that was the whole point?

[MarkyB]

That sounds OK, it will only show a charge when the battery needs one.

[IslipMinor]

The wire(s) from back of the alternator should go directly to the ammeter and from the other side of the ammeter to the starter solenoid or pull switch. The large brown wire that was connected to the starter solenoid/switch, and feeds all the car electrics, has to be moved to the same side of the ammeter as the alternator connection. If there are other wires connected to this terminal that have been added to supply 'extras', these must be moved to the ammeter as well. As a check, any additional wires must be fused as soon as practical after the connection to the ammeter, or the original solenoid/switch terminal if no ammeter is fitted.

With the connections made in this way the ammeter sees all the load being taken from the battery, except the starter motor, and with the engine not running will show a discharge equivalent to the total load switched on. With the engine running, as speed builds up to cover the 'switched on' load (assuming that the alternator is big enough as well), the ammeter will move from it's 'non-running' level of discharge through to a charge that the state of the battery requires to charge it. After a long trip, this should be very close to zero. If it is not it will usually indicate the battery is failing.

The diagram below shows the alternator charging circuit with an ammeter as well:
[frame][/frame]
The wires used for connecting the alternator and ammeter must be capable of taking the full ammeter output current. With the Lucas ACR range there are 2 large output terminals and for anything more than an ACR17 (38A) it is easier to run 2 smaller cables, one from each alternator connection, that together give the total capacity required. As a guide:
[frame][/frame]

[bmcecosse]

Put the headlamps on for a couple of minutes and THEN start the engine - does it now show a charge (or discharge if connected wrong way round ) for a few seconds ??

[little_pete]

Wow, very thorough explanation! I'm going to remove it for now I see the benefits but I just want to keep an eye on oil pressure and occasionally temperature. I feel these are more critical and don't want too much going on. I still find the Morris takes a little more brain power to drive than my modern car. I have got a 35 amp 6mm2 gauges 'commoning' block which is well insulated. For now I'll join these wires together and remove the ammeter from the occasion. When I've got more time I'll track the wires back and remove them as they are a potential hazard. (the previous owner has put two fuse boxes in and removed the old regulator, one fuse box is inside the car the other is where it should be)

[little_pete]

Well I can identify one wire goes to the fuse box Heavy gauge red One wire is brown and blue (medium size)

There are two other wires which I don't know what they are

There are two red wires coming from the alternator into the (home made loom) I guess these are the wires from the alternator (two wires to spread the load as you described)

Should I connect the two wires directly to the start solenoid (battery side) just as a way of connecting to the battery, then run a wire from there to the live of the fuse box? and connect the brown/blue wire to the solenoid (battery side) also?

Or should i just do my bodged method of joining all 4 wires together in a safe terminal block and then using half a roll of electrical tape?

[bmcecosse]

I would do as you suggest - direct to the solenoid block battery side. Is there also a smaller wire running to the alternator - to power up the (so called) Ignition light ?

[little_pete]

Success I think. Ammetter removed, oil pressure gauge moved down to below the main dash to the right of the wheel (should be a dual gauge but the damn water plug won't fit need to get a horrendously expensive adapter and pay postage on it because I can't find any locally.

Thanks for your help with the wiring

Oh I found the brown and blue were for the headlamps is there any reason why I shouldn't fuse them? I've put them on the Fused side of the fuse box and they work well for now?

[bmcecosse]

The feed wire to the fused side of the fuse box won't be large enough to handle the headlamp current......It should be supplied from the brown wire - normally via the regulator which I assume has been removed on your car. If you insist on fusing headlamps - do each filament independently - so you are not suddenly plunged into complete darkness...... Happened to me on my rally Mini in the middle of a night special stage - not funny. I hadn't wired the car - and hadn't appreciated ALL the lighting relays went through one control fuse......

[little_pete]

what is the concern here the thinner wire to the fuse box may breakdown it's insulation if the amps of the headlamps are used? The feed wire to the fuse box (From the battery side of the solenoid) is the 35amp cable, thicker than the headlamp cable. or have I done something wrong? The live of the fuse box now has a direct route via 35amp cable to the battery and alternator.

Has anyone calculated the amps of heater, wiper and fuel pump? does the second fuse need to be quite so high?

[little_pete]

Yes fusing them independently makes sense, also wiring them independently wherever possible like a modern car instead of splitting them as late as possible.

[bmcecosse]

Your wiring has been changed then - if the 'main' cable goes to the fuse box -although it is always a brown wire - but originally from the Regulator. If it's thick then that will be fine. The 35 amp fuse is excessive - but it's low enough to blow in event of a short circuit, but without letting go just because all are switched on together -which happens if all are left ON - and then the Ignition is switched on - especially if the wipers are asked to drag over a dry screen!

[little_pete]

Yes the regulator had been removed already when I got the car. I have presumed that the alternator has a built in regulator or equivalent and now used the solenoid battery side as my main source of power. The previous owner has done the wiring himself and wrapped the loom in 50 rolls on insulation tape, making alterations a sticky mess.

I'll independently fuse the lights at another time it's a good idea.

[IslipMinor]

I would not use the fusebox fuse for the headlights as the actual 'continuous rating' of the glass 35A fuse is 17.5A - they are design to 'blow' at 35A.

Depending on the bulbs fitted, the headlight load (including sidelights and panel lights) is around 11/13A on dip and 12/14A on main - so it does not leave much for the standard items already connected to the fuse. Which fuse have you connected the headlights to?

The 'live' fuse has the horn(s), which take 3/4A each and the interior light (0.5A!) and the 'ignition' fuse has heater (3A), wipers (3/5A wet/dry) and brake lights 3/4A) - all these are normal running loads and all have a higher 'inrush' current draw when they are initially switched on.

[little_pete]

I have it on the permanently on side. Halogen bulbs, so what will I be running off that? brake lights? and horn

14A+3A ok potentially brake lights will push it over the 17.5A running with main beam and horn all the same time. So don't brake and use the horn at the same time in the dark ;-)

Perhaps I should move it back, the more fused wires I have the happier I feel that the car won't spontaneously combust

[bmcecosse]

Brake lights (in UK) are normally on the IGN controlled circuit. But I do know that USA cars in general do (sometimes?) have the brake lights on the constant ON circuit. But you are not putting the headlights through the fuse - so don't worry!