# how to connect a digital meter between alternator and batteries

#### dsswerwe

Jul 13, 2023
4
We are using a 24v 100A external alternator in our vehicle to charge leisure batteries. We need to monitor alternator’s voltages and amperage on a digital meter but the alternator is grounded with vehicle’s body and vehicle also has an external system grounded with its body, so alternator current is dividing between system and leisure batteries. I just wanted to ask how I can connect digital meter between alternator and leisure batteries so I can get total voltages and amperage on my digital meter from the alternator.

#### Externet

Aug 24, 2009
891
Taking the word 'alternator' as being a direct current generator,

GNDvehiclechassis---------(-)24V.alternator(+)------"A"---"B"-------(+)12V battery(-)------+)12V battery(-)----------GND

Connect a voltmeter +probe to point "A" and its negative probe to GND to read volts.
Connect a 150Amperes current meter between "A" and "B" with its negative probe at "B" and remove any connection between "A" and "B" to read Amperes.

#### Bluejets

Oct 5, 2014
6,920
Do the intelligent thing, forget about series ammeters, simply latch a DC tong meter over the main power positive or negative battery lead.
Voltmeter (any basic unit) simply connects to the battery.

#### kellys_eye

Jun 25, 2010
6,514
Given the potential levels of current flow the average meter wouldn't survive (max 10A on many of them). If you have - or get - a DC reading clamp ammeter you can connect this to any cable without breaking the circuit wiring and can measure currents up to 100's of amps.

#### Delta Prime

Jul 29, 2020
1,966
We are using a 24v 100A external alternator in our vehicle to charge leisure batteries
What is the chemistry of your leisure batteries?
If resources are limited at least to diodes for isolation.

#### Bluejets

Oct 5, 2014
6,920
If resources are limited at least to diodes for isolation.
Additional information pending, I'd say, from the written requirements above in the original post, no "vehicle" electrics are involved requiring any "steering".
To me at least the word "external" verifies it.

#### Delta Prime

Jul 29, 2020
1,966
That is a prerequisite here.
I'd say, from the written requirements above in the original post, no "vehicle" electrics are involved requiring any "steering".
To me at least the word "external" verifies it.
Thank you for the information.

#### Bluejets

Oct 5, 2014
6,920
Makes absolutely no difference in answering the Op's query.

#### Delta Prime

Jul 29, 2020
1,966
Makes absolutely no difference in answering the Op's query.
My fault! I was asking a question?
It seems my dementia is right on time.

#### Kiwi

Jan 28, 2013
471

What make and model alternator(s).

What do you mean by "external alternator"?

24v, so guess you are probably not in the USA?

#### Bluejets

Oct 5, 2014
6,920
24v, so guess you are probably not in the USA?
Or it's from a truck system......

#### Kiwi

Jan 28, 2013
471
Looks like the op has given up on us?

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