Thread: Adding Extra Panels to an existing system

Just plug the portable set into a power connection near the battery and they'll be fine. The only thing to note is that your cables should be thick enough to avoid too much voltage loss between the controller and the battery.

Thanks Bee utey. I thought that would be the case, but I wondered if the two controllers would squabble. But I guess all they see is the battery voltage and lifting that with the input from another pair of panels isn't going to change the way the controllers operate.
Cheers

Coop

Originally Posted by C00P

Thanks Bee utey. I thought that would be the case, but I wondered if the two controllers would squabble. But I guess all they see is the battery voltage and lifting that with the input from another pair of panels isn't going to change the way the controllers operate.
Cheers

Coop

AFAIK you are correct Coop, the two regulators will confuse each other. You will only effectively be using the power from one controller.

Better to bypass the regulator on your portable panels and connect this into your existing charge controller. Make sure it can accept the total input watts from all your panels first.

Originally Posted by kelvo

AFAIK you are correct Coop, the two regulators will confuse each other. You will only effectively be using the power from one controller.

Better to bypass the regulator on your portable panels and connect this into your existing charge controller. Make sure it can accept the total input watts from all your panels first.

Not sure how regulators can get "confused" unless they're smarter than the average kelpie. My bush camping system has two separate regulators and never had any problems. If my batteries are sufficiently low at dawn both regulators together can't lift the battery voltage above 14V until the batteries recharge and one regulator then slows its charge rate first.

Originally Posted by bee utey

Not sure how regulators can get "confused" unless they're smarter than the average kelpie. My bush camping system has two separate regulators and never had any problems. If my batteries are sufficiently low at dawn both regulators together can't lift the battery voltage above 14V until the batteries recharge and one regulator then slows its charge rate first.

My understanding is this;
Regulator A with 120w panel is changing the battery at 14.2V, regulator B with 120w sees this 14.2V and thinks the battery is charged so it goes into 'float' mode. So in effect you are only using 120w to recharge the battery.

Using one regulator with both 120w panels connected would give you the full 240w of power to recharge the battery.

The above is assuming your solar regulator is able to accept a 240w solar input and is also able to output the 240w.

A 10amp regulator may be able to have 240w of solar connected but can only ever output 10amps. So if using one regulator you would need to make sure it is the correct capacity to make the most of your setup.

Originally Posted by kelvo

My understanding is this;
Regulator A with 120w panel is changing the battery at 14.2V, regulator B with 120w sees this 14.2V and thinks the battery is charged so it goes into 'float' mode. So in effect you are only using 120w to recharge the battery.

Using one regulator with both 120w panels connected would give you the full 240w of power to recharge the battery.

The above is assuming your solar regulator is able to accept a 240w solar input and is also able to output the 240w.

A 10amp regulator may be able to have 240w of solar connected but can only ever output 10amps. So if using one regulator you would need to make sure it is the correct capacity to make the most of your setup.

If indeed one set of panels plus one regulator can raise the battery voltage to 14.2V then no matter which way you add the extra panels the voltage will attempt to rise above the regulator's set voltage and be cut off from supplying the batteries. A battery cannot accept a high current and stay below 14.2V if it is nearly full. That is simply how a lead acid battery works. It is not some kind of bucket you can fill at a maximum flow rate of amps right to the top.

The point is that if the batteries are sufficiently discharged or there is a big enough load on the system (eg an appliance drawing 500W via an inverter) then both sets of panels with their respective regulators will see a voltage well below 14V and they will both supply full current to the system.

Oh and if you hook up more panels to a regulator than it is designed to handle then you will probably burn it out. They have specifications it's wise not to exceed.

Originally Posted by bee utey

If indeed one set of panels plus one regulator can raise the battery voltage to 14.2V then no matter which way you add the extra panels the voltage will attempt to rise above the regulator's set voltage and be cut off from supplying the batteries. A battery cannot accept a high current and stay below 14.2V if it is nearly full. That is simply how a lead acid battery works. It is not some kind of bucket you can fill at a maximum flow rate of amps right to the top.

The point is that if the batteries are sufficiently discharged or there is a big enough load on the system (eg an appliance drawing 500W via an inverter) then both sets of panels with their respective regulators will see a voltage well below 14V and they will both supply full current to the system.

Oh and if you hook up more panels to a regulator than it is designed to handle then you will probably burn it out. They have specifications it's wise not to exceed.

I said "Regulator A I with 120w panel is charging the battery at 14.2v" not meaning the battery is actually at 14.2v ie remove all charging input and the battery voltage could drop to 12v. The second regulator sees the 'charging' voltage from the first regulator and thinks this 14.2v is the battery voltage, at which point the second regulator goes into float mode. NOTE all voltages being used are random voltages, actual voltages may differ

Your last comment was covered when I said "So if using one regulator you would need to make sure it is the correct capacity to make the most of your setup."

Originally Posted by kelvo

I said "Regulator A I with 120w panel is charging the battery at 14.2v" not meaning the battery is actually at 14.2v ie remove all charging input and the battery voltage could drop to 12v. The second regulator sees the 'charging' voltage from the first regulator and thinks this 14.2v is the battery voltage, at which point the second regulator goes into float mode. NOTE all voltages being used are random voltages, actual voltages may differ

Yes and adding two more panels to the first regulator will not charge a battery any faster as it's already at a high output voltage in your example. The regulator will simply reduce the current to match.

Oh and that bit about the voltages being randomly chosen shows you don't understand electrics, with battery charging achieving the correct voltage is very important.