Solar charging

[the evil twin]

If the reg I have, CMP12 is rated for both 12 and 24v, which it is, going by the specs I found it should "auto switch" between 12 and 24v. Which it seems its not.
Plus the load light is on even when there is no load at all, just connected to a bare battery.

Mudski... the Reg is designed to switch automatically between 12 and 24 volt solar panels not Batteries. The battery has little to do with it once the panels are connected.

As mentioned prev the load light is "On" because the battery is capable of supplying the load.

Pls excuse the boldface in teh next bit, I did it to highlight what I think is happening from your description and not meaning to be at all insulting...

The "charge" light will illuminate only if there is sufficient solar input to run the load (if connected) AND something left over to charge the Battery OR there is no load just a 24 Volt battery bank and the panels are 'charging' itBUT the battery bank voltage MUST be over 19 odd Volts IF there are 24 Volt solar panels connected. Any battery voltage under 19 volts is considered a fault and the lo voltage cutout activates to prevent damage to equipment.

As Cupp said... a 24 volt solar system won't charge a 12 volt battery with that Reg you have.

A point to note here for everyone (and I see it occasionally) is that if you deplete your battery during the night or very cloudy weather below the Low Voltage Cutout setting of your Solar Reg you will need to temporarily jump another battery or partially charge the flat one with a Charger to fool the Solar into coming back on.

It happens often enough out bush that I get gifted the odd couple of cans every now and then getting peoples systems going again.

Disclaimer... it can be a tad difficult trying to fault find on the 'Net and there could indeed be faulty gear involved. The above is just my wild hairy rrsed best guess

[mudski]

Mudski... the Reg is designed to switch automatically between 12 and 24 volt solar panels not Batteries. The battery has nothing to do with it once the panels are connected.

Ah so its the "input voltage" it will switch on. Not he "output voltage" So regardless of the reg thats on there, its setup for a 24v system. That reg can be used for 12v or 24v panels. I'm getting there.
http://www.jutasolar.com/en/product_more.asp?id=1185

As mentioned prev the load light is "On" because the battery is capable of supplying the load.

I thought it was there to say it was receiving or reading load, like a fridge, at the same time whilst charging...

Pls excuse the boldface in teh next bit, I did it to highlight what I think is happening from your description and not meaning to be at all insulting...

Takes a lot to insult me mate. I appreciate you being so patient with me on this. I know your head butting the desk a lot by now but I can see this turning into a big shit fight with the people who I bought it from. I just want to get all my facts right so I have a better chance of getting a refund, or, an exchange for the right ones.

I really do appreciate the help you, cuppa and everyone else has done so far. Before I bought these I really thought i had bough the right thing, I didn't go for the cheapest on there too. I did research, not that you can tell but as far as my knowledge would take me, and this is where I end up. With a sub $400 useless folding POS. Haven't told the missus yet. She's gonna shit a brick too.

[the evil twin]

ROFL... yeah, scary things them missus's. Mine can freeze my brain and turn my legs to jelly from 30 feet away with one scornful look

[mudski]

Mate, sorry to make you head but the desk again. I am just looking at the specs of this regulator.
High Voltage Disconnection - 13.7V -27.4V
Low Voltage Disconnection - 10.5V -21.0V
Low Voltage Reconnection - 12.6V -25.2V
I read this as it can do both 12v systems and 24v systems. I.e it will disconnect if it reads a low voltage of 10.5V for a 12volt system (one 12v battery) or disconnect at 21v for a 24v system (2 x 12v batteries or one 24v battery) Or am I reading this wrong?
I am so sorry to do this to you.

[the evil twin]

Yes, your Reg will work on either a 12 Volt or a 24 Volt system but not a combination. Given the above figures for a 12 Volt panel connected to the Reg with a 12 Volt battery bank to Batt terminals and the load to the Load terminals my understanding would be...

High Voltage Disco - The reg will disconnect the panel output when/if the battery voltage reaches 13.7 volts. You will see this happen with a Voltmeter placed across the battery terminals if above 13.7 then the Panel terminals (on my own reg reads approx 18 volts) will be 4 or more volts higher.

Low Voltage Disco - The reg will disconnect the load from the battery if the Battery Voltage falls below 10.5. This is why some people hook the load (fridge and lights etc) to the battery bank and leave the load terminals vacant

Low Voltage Reconnect - The reg will reconnect the load after a LV disconnect when the voltage is above 12.6

Green LED will illuminate whenever the Solar Panel Voltage is above Battery Voltage

Red LED will illuminate whenever Battery Voltage is above low voltage disconnect

In a balanced system you should only very rarely see a Low Voltage Disconnect in unusual weather or useage. Recurring LV disco's essentially mean that the battery capacity is too low and being depleted overnight or that the Panel Output is too low to replenish the power consumed by the load.

Not all the above may be 100% kosher as different manuf's will use the same terminology but may slightly differ in how their regs handle the different conditions.

Either way if you try a combo you will either have a 24 Volt panel with the Reg thinking the Battery is too low a voltage IE below 21 Volts or a 12 Volt Battery with the Reg thinking the panel is too high as your panel OP is minimum 19 Volts or more

[mudski]

Something just clicked in my head which is what was confusing me most. If I have 24v panels, this particular "multi voltage" reg will only charge a 24v system. If I have 12v panels, it will only charge a 12v system??? Please tell me I'm getting this right.

[Cuppa]

High Voltage Disconnection - 13.7V -27.4V
Low Voltage Disconnection - 10.5V -21.0V
Low Voltage Reconnection - 12.6V -25.2V

I think ET has explained it well.
However those figures reveal why it makes sense to get a better regulator.
For example, in a 12v system, 13.7v is way too low for High Voltage Disconnect (HVD). 13.7v is only a float voltage for many batteries. 14.1v to 14.4v is common for the bulk charging stage of the charging cycle, & with temperature compensation can rise higher. The HVD setting on my Morningstar Tristar reg is adjustable to suit different battery types, & for my AGM's is set at 14.9v.

13.7v would eventually charge a 12v battery, but it would take an awful long time, far to long to make it practical in a 24 hour usage pattern such as when camping.

The 10.5v LVD figure is also ridiculously low. When a 12v battery gets that low it is already seriously flat & doing damage, severely reducing it's life expectancy. For better quality non adjustable regs the LVD is usually in the low 11’s, & adjustable ones allow for settings in the high 11’s or even the low 12’s.

For a reg to allow a 12v battery to drop to 10.5v & then not start to recharge it until 12.6v is an excellent reason not to use the load function of such a regulator as to do so turns an inefficient (13.7v HVD) battery charger into a battery 'murderer'.

This is why I have 2 or 3 of those regulators sitting unused here at home. Useful for keeping fully charged batteries topped up with a 'float' charge, but that is about it.

Cuppa

[the evil twin]

Something just clicked in my head which is what was confusing me most. If I have 24v panels, this particular "multi voltage" reg will only charge a 24v system. If I have 12v panels, it will only charge a 12v system??? Please tell me I'm getting this right.

You nailed it, Cobber

P.S. there are drugs that help with the clicking noises in the head

[threedogs]

He's right about the meds, been watching

[mudski]

O.k great. Thanks everyone for their input. The mob whom I bought them from has respond with a RMA form and asked for a description of the fault. Basically I can say that I purchased a system for 12v as advertised, but have received a system with 24v panels supplied and regardless of the mutli voltage regulator it will not suit a 12v system, which is what I paid for?