Ammeter guage with sender?

[rcx106]

All the ammeter guages I've seen require that a heavy guage cable runs to the ammeter guage, ie the full current goes into the cabin to go through the meter. I don't really want to do that and it doesn't seem sensible. I've found one guage that uses an inline sensor. And I've heard of guages that just have some induction sensor that goes around the battery cable to sense current. But can't find one! Anyone know?

[rcx106]

I always ask too soon, I Google _inductive ammeter_ and found half a dozen car ammeters that use an inductive pickup.

[rcx106]

Ah, inaccurate? Maybe that's why lots of them still use a shunt. I want to monitor how much power is being used from the battery and how much from the battery, when powering a fully loaded 4x4 winch. Reason being that I want to balance the battery and alternator size to get max effect at min weight (ie I don't want two batteries like everyone else if I can avoid it). I've only found one auto ammeter which can handle the output of my upgraded 110A alternator. And only marine ammeters can handle the 220A that my winch will draw. So I'm now looking at non auto ammeters, just regular meters that can be temporarily connected.

[rcx106]

Thanks Doctor Volt. What I want to know is how much power the winch takes from the battery and how much from the alternator. It's much curiosity but also I've fitted in a fat heavy alternator only to be told later that the winch will primarily take power from the battery and not the alternator (though two engineers have told me opposite stories).

Anyway, RS Componants do heavy duty ammeters for little over a tenner each so I'll connect them up temporarily and see. I've given up the idea of a cabin ammeter because it's too costly and too much effort. If most power is taken from the battery then I don't see the point of a fat heavy alternator if all I get is faster battery recovery which I don't need. So I'll revert to my stock alternator and fit a bigger battery instead.

[rcx106]

So two offline engineers have said these two opposing stories (as far as I understand it)

One says that the alternator, providing it's turning fast enough, will generate the higher voltage. Whereas the battery voltage drops under load, meaning that most of the power will come from the alternator. This is what I hope is true as a bigger alternator is lighter than a bigger battery, and I've already fitted a nice 110 Amp alternator

The other engineer says that in his experience, a lead acid battery is better at providing instant power on demand and thinks that's where most of the power will come from.

[rcx106]

The winch I bought in the end is 190A at full load. I know that at full load the battery will at least need to be contributing. I'm just curious where the power primarily comes from under normal use (maybe half load, so ~95 Amps)