On 19 August 2025 at 13:05 duncan webster 1 Said:

I’m almost tempted by a bucket of salty water and two electrodes!

not a good idea. gives off dodgy fumes

Connect to battery as normal and you will see the voltage go up as a charge is put into it. If there is a controller in circuit and it is fully charged it may ‘turn off’ so just take some power from the battery for a few minutes to drop the voltage and it wi start chargibg again, Then when it is in charge mode again you can try covering bits up.
To get an idea of how much power is available with a low current capable meter make your own shunt with a bit of iron fence wire or a nail when the state of charge is high enough to have reduced the charge current to about 5 amps Measure the voltage across your shunt and that represents 5 amps but keep the shunt cool in a bucket of clean water. You can then get an idea of higher currents as you draw more power from the battery on a sunny day.

On 21 August 2025 at 11:52 duncan webster 1 Said:

I can’t get to the track now till next week because of a ‘music’ festival. I live 4 miles away and it still keeps me awake.

I still don’t understand CCV. If it means close circuit voltage that implies just shorting the output, so there is no voltage to measure. If it means voltage when loaded that will depend on load. Does it mean voltage when producing rated power?

I’ve obviously connected the panel to the controller and battery. If the battery voltage doesn’t increase there are 3 possible faults. Another club member has come up with a 20A meter, that’s next week’s job.

I like the energy monitor thing, thanks, I’ll probably be buying one of those

 

An AI Google search reveals this comment, though my earlier one still seems relevant, as you probably should measure charge and float voltages, appropriate to the battery technology if testing one yourself.
Battery manufacturers such as Odyssey are quite specific about their needs.
“AI Overview
Measuring the Output Power of a Solar Panel
CCV in the context of solar panels refers to Constant Voltage (CV) mode in a solar charge controller, where it regulates charging to a set voltage to prevent battery damage.
It’s not a direct panel measurement like Open Circuit Voltage (Voc) or Short Circuit Current (Isc); rather, it’s a system-level function that monitors and adjusts battery voltage.
To measure a solar panel’s voltage, use a multimeter set to DC voltage, connect it to the panel’s leads in sunlight, and disconnect it from the battery and charge controller first to get the Voc.”

Also points to this video amongst several others

Regarding DC clamp ammeters, when my 30+ year old Heme-600 died last year, I bought one of these.
Yes I’m sure Fluke and others are better, but this seems to work for my own needs, though mine came from a different vendor; I do have a wide variety of other high quality digital and analogue multimeters.
https://www.ebay.co.uk/itm/356500144334
Other sources are available, some considerably cheaper if you search around, but I wanted a UK seller.

Bill

A very impressive meter there, Bill … thanks for the links.

MichaelG.

GL is a gel battery so the acid is made into a gel so it doesn’t slosh around but also can’t vent gas so easily so needs more careful charging, like a sealed battery. If your battery has filler plugs it is a flood which all car batteries used to be but not always for the last 20 years.