Multimeter, checking load?

With the ammeter, all the current needs to flow through the leads.
Use the 10amps setting. That usually means the red lead needs to be moved to the third socket on the multmeter.
Turn off all appliances like the fridge.
Take off the earth cable on the fullriver battery, and connect one multimeter lead to the earth terminal on the battery and the other lead to the earth cable that was removed.
What reading do you get?

To drop from 12.8v to 12.2 volt over 3 days, you're losing up to 0.4 of an amp, assuming your battery and charging are fine.

GT, you're nearly there. You need to put the multi meter in series with the current flow.

1. Disconnect the positive terminal on th battery.
2. PLace the red probe in to the socket on the meter marked DC amps. ( Black most likely stays in common socket)
3. Select DC amps on the multimeter.
4.

GT, you're nearly there. You need to put the multi meter in 'series' with the current flow.

1. Disconnect the positive terminal on th battery.
2. Place the red probe in to the socket on the meter marked DC amps. ( Black most likely stays in common socket)
3. Select DC amps on the multimeter.
4. Place Red probe on Positive terminal of battery.
5. Place Black lead On vehicle's positive terminal clamp.
6. - If you have selected DC amps, with the probes connected above, and measured across the + and - batt. terminals, ( as for a Voltage test) you will have blown the fuse inside the Multimeter, that protects the Amp measuring side... MM still tests Voltage OK, but will read 0.0 for amps, as it will be an open CCT with fuse blown.
7. If fuse OK, you should now be reading how much current is being drawn. anything more than about 10 to 20 Milliamps, is an issue. Depending on veh. type, minor current will be required to operate such items as securirty alarm auto doors, etc.

I once installed a small jaycar thermometer did inside and outside, that was "recommended" for full time installation, that drew 100mAmps. !!!

Have you recently installed any electrical goodies?? reverse camera's are another one that draw a fair bit, and owners dont realise that they draw current, in some cases when the monitor is off....

Good luck,
Jarrod.

This looks like a useful site for info regarding using multimeters:

www.doctronics.co.uk/meter.htm

Mike Harding

Mike thanks for that link

Jarrod & Phil I should have said the camper is off the vehicle and disconnected.
The Fullriver is in the camper itself

Anyway using both of your suggestions it appears it is the fridge itself.
With the compressor off it still _Affordable_Storage_Drawers.aspx 0.3 amps. I have eliminated everything else.

The fridge is a 60l Trailblazer but it has an optional thermometer and voltmeter.
Both are analogue instruments (Refco and Faris respectively)
That is what must be drawing the current.
When you start the compressor it _Affordable_Storage_Drawers.aspx 7.5.

Could a thermometer and voltmeter draw that much?

Thanks for your replies I've learnt something about electrics today.

GT your problem is: -> your 80ah Fullriver battery has gone from 13.5V to 12.2V over 3 days with nothing turned on"

Your 13.5v reading was taken when the battery had recently been charged by driving or being on a battery charger, and yes 12.2v is far too low for an AGM battery even while actually powering a fridge.
The fully charged voltage of a Fullriver AGM is 12.7v so 12.2v is far too low and indicates a problem.

Carefully remove the battery, take it to a battery 'specialist' and ask them for a "deep discharge test" to be done on it and only if it's 100% then ask them to fully 'recharge' it if it requires a charge, unless you have a seriously decent 10A 'plus' battery charger.

When you’re happy the battery is fully charged then re-install just the battery,
(NOTHING else at this point) connect the (-) cable to a clean perfect earth and the charging cable from the 'isolator' to the (+) terminal.

Run it this way with no attachments for as long as you can, at least for a few days.
The voltage should then be checked at least 4 hours after the vehicle has stopped or better still after lunch the following day, to allow the AGM DC battery to return to its normal fully charged setting of 12.7 Volts, if it's not about 12.7v and you were advised the battery is perfect then the fault is in the (+) or (-) battery cabling connections or isolator system.

If the battery is 12.7v connect just one item at a time, and once again monitor the battery voltage as mentioned above over a few days, this way you will find any faults yourself and you will be satisfied with your achievements.

In this instance you will be checking battery Volts not Amps, the mutimeter 'dial' will be set at DCV 20

"Its gone from 13.5V to 12.2V over 3 days with nothing turned on. "

If you have a brand new battery with nothing connected to it, then it will drop from 13.5 to 12.6 volts.

Are you measuring the battery voltage after it has been disconnected from any load for several hours ? If not, the measurements are meaningless.

If the battery has gone faulty, then it will discharge below 12.6 volts with nothing connected to it.

OK, so you've measured 300mA draining out of your battery. Next step is to disconnect stuff to see what's drawing the power. What's the reading after you disconnect the trailblazer and the power hungry meters??? :-)))