Battery power to the ammeter gauge on an old tractor?

rasman57 · Jan 3, 2011

When wiring up an ammeter with battery supply, I see some of the wiring diagrams in the archives show the ammeter wire source coming from the starter power stud up to the ammeter. Is 8-10 gauge wire ok for that run of less than 3 feet? My battery is under a floorboard and getting power to the ammeter direct from a battery post will not work. I will not have any other wire on that side of the ammeter other than supply. The power for lights, the alternator (63 amp) output and ignition switch power will all be on the other side of the ammeter. This sound reasonable. I hate the smell of burning insulation and smoke always surprises me in a very bad way. Thanks

Mike in Mn. · Jan 3, 2011

10 ga. should be ok for that short run. Grab the hot battery cable wire off the starter solenoid and run to the amp meter for supply. Lights, alt, and ign. on the other side as you stated should be correct. I use bare crimp connectors and then solder and shrink tube them, but use only rosin core solder on elec. wires. Auto parts store has small dia. low temp rosin core solder that is real east to use.

36 Coupe · Jan 4, 2011

Small terminals and wires connected to a battery terminal will be eaten up by acid.

John T · Jan 4, 2011

Id probably use 8 Gauge from the alternator output to the ammeters LOAD TERMINAL and from the ammeters other SUPPLY TERMINAL to the battery. Theres only one wire on the SUPPLY thats to the battery while the LOAd is where the alternators output wires along with feeds to loads like lights and ignition.

Often when lay persons consult a wire gauges ampacity chart they look at enclosed conductor ratings versus single conductors in free air which can carry more current. A person could even run 6 gauge while 10 probably still wouldnt overheat so bad the insulation is damaged. It dont hurt to use overkill in bigger wire as it reduces voltage drop.

A typical place for attaCHMENT IS WHERE THE BIG BATTERY CABLE ATATCHES TO A STARTER SWITCH OR SOLENOID as a huge cables goes from there right to the battery.

The alternators output is where the highest current flows so Id run 8 gauge from the alternator output to the Load (NOT battery) side of the ammeter and then from the Supply side of the ammeter to the starter post.

John T

buickanddeere · Jan 4, 2011

Put a fuse between the ammeter and it's connection
to battery.
Surprising how many people forget that. Handy
place to pull a fuse and keep tinkerers from
borrowing your tractor or running the battery down.

rasman57 · Jan 4, 2011

(quoted from post at 14:49:44 01/04/11) Put a fuse between the ammeter and it's connection
to battery.
Surprising how many people forget that. Handy
place to pull a fuse and keep tinkerers from
borrowing your tractor or running the battery down.

All good advice and thanks to you guys. How big of an inline fuse would go on that supply line from the battery. It has a 10si delco 63 amp alternator and only a set of old school headlights. It is on my property and never roaded so no other lighting and no cab etc. I like the safety and security idea.

buickanddeere · Jan 4, 2011

I don't know if there are generic fuse holders for
those GM Maxi fuses or not?
Going to need a 50 amp slow blow or a 60+amp fast
blow.
If nothing else an ordinary industrial 208,480 or
600V fuse holder with a "pull out" block would work.
Usually lots of them for free in junked control and
power panels.

M Diesel · Jan 5, 2011

(quoted from post at 16:06:52 01/04/11) I don't know if there are generic fuse holders for
those GM Maxi fuses or not?
Going to need a 50 amp slow blow or a 60+amp fast
blow.

Yeah they make them. I put 100 and 50 amp blade types in my truck. Got them at a parts store. Pep Boys I think.

Battery power to the ammeter gauge on an old tractor?

rasman57

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Mike in Mn.

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36 Coupe

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John T

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buickanddeere

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rasman57

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buickanddeere

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M Diesel

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