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Ammeter Indication

Ammeter Indication

I hope this question doesn't end up on the web site with my name under it. A chance I'm willing to take. Reference the amp guage. Minus (-) to the left, plus (+) to the right. The car has a positive ground elec. system. Here is the question. While driving down the freeway. the amp indication is to the minus(-) side. Is the battery being charged or discharged? It would seen that since the negative side of the battery is the "power" side, an indication towards that side would be good. So how come my new battery is dead? The wiring of the big electric fan was corrected and now goes through a relay before anything else. Correct me if I'm wrong, but that means the battery only has to energize the relay and not the fan itself. Tomorrow the cooling system gets another test drive. One potentially leaky, flexible hose was replaced. One shop said a hose would never collapse with the suction of a water pump on it. The other guy said definitely could happen. I got a new hose. This is absolutely the last idea I, or anyone else has come up with to resolve the cooling problem. Someone did suggest sucking on the vaccuum hose. Even though I don't understand that, there is one thing left to try. (hope that wasn't a tongue in cheek suggestion). By the way, the battery is one week old. I await your feedback. Aloha, (name withheld by request; ha,ha), XK-140 FHC

With the needle to the minus side, the battery is being discharged, unless the amp guage is connected backwards. With the engine stopped, which way does the needle go when the lights are turned on? That is the discharge direction. No, the battery (with a little help from the generator) must still provide the power to the fan. It may be that the relay now bypasses the amp guage, so that the fan doesn't seem to draw power, but that is just an illusion. Have you measured how much current the fan actually pulls? It might also be worth getting the current regulator section of the voltage regulator adjusted to make sure the generator is giving the charging current you are entitled to. If your cooling is still not right, I suggest you measure the temperature at the top and bottom hoses. I am sure you will beat your cooling problem, and then you can put the electric fan on a thermostat so that it only runs part of the time, and your generator can keep pace (on average). - Good luck, Mike Morrin

Discharged. Rob, you've got a charging problem or a BIG draw on your system. Is the big aux fan you put in running while driving at speed? And I know speed in aloha land is a relative thing compared to stateside. I've never seen anyone other than me exceed 55MPH on the islands. - George Badger

Oops. I missed the question about the relay. The battery still must energize the fan. Just goes thru the relay. Power is power. - George Badger

Hi Rob & all -- on my original Mk IX, positive ground, ammeter shows "C" (for charge) on left of needle, "D" (for discharge) on right of needle -- above 1,000 RPM, reading on "C" side or in the middle when batteries are fully charged. Are you SURE yours has minus (-) to the left? If so, Jaguar must have changed something in the electrics between yours and mine -- or else a former owner replaced the gauge with a non-correct one. Does your ammeter say "Lucas" (or "Smiths") on the face? If not, it's not a correct gauge. On mine, all gauges say "Smiths" except ammeter, which says "Lucas." Hope this helps -- Larry Martz

The local guru of things electrical and automotive suggested if I wanted to put an electrical rad fan on my XK140 to reverse polarity and put on a 75-80 Amp. alternator. Otherwise I would discharge my battery very rapidly. - Bill, XK140 OTS

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