Dual Input using 3 Position Battery Switch

[TheCoachStone]

I have a small solar array and system that charges 2 batteries in 24v. I also have a 48v battery system that I use with my portable solar setup. I was wondering, if I install a 3 position battery switch could I hook up a Blue Sea 3 Position Battery Switch can I hook the solar into one and the battery into the other?

So, I would hook one prong to the battery, one prong to the + of my solar, and run the output into the solar input on my solar controller.

This is the part I am thinking about using - https://www.amazon.com/Blue-Sea-Sys...ds=3+way+battery+switch&qid=1647618956&sr=8-3

 

[chrisski]

Those switches are rated to 48 volts. The charge is likely 54 volts and if equalizationhappens could be in the 60s. The Blue Sea switch I already had installed is one of the reasons I did not upgrade from 12 votls to 48 volts, and went with 12 votls to 24 volts. I don’t know what people with 48 volt systems use, but some do use this switch. I looked for a switch rated to 65 VDC, and it got expensive.

I would need a diagram to understand the question. The switch you have pictured could choose position 1 on, OFF, or Position 2 on, but not both at the same time. However you wired it.

 

[Supervstech]

I have a small solar array and system that charges 2 batteries in 24v. I also have a 48v battery system that I use with my portable solar setup. I was wondering, if I install a 3 position battery switch could I hook up a Blue Sea 3 Position Battery Switch can I hook the solar into one and the battery into the other?

So, I would hook one prong to the battery, one prong to the + of my solar, and run the output into the solar input on my solar controller.

This is the part I am thinking about using - https://www.amazon.com/Blue-Sea-Sys...ds=3+way+battery+switch&qid=1647618956&sr=8-3

I don’t understand what you are trying to accomplish with the switch…

24V setup and a 48V setup connected to a single PV? This sounds dangerous.

Please explain exactly what you want the switch to do.

 

[timselectric]

I believe that they are wanting to select between feeding the SCC for the 24v system. With either the solar or the 48v battery.

 

[HRTKD]

Many solar charge controllers automatically determine the system voltage when they are first initialized and then never again automatically. In other words, it's determined once. If the system voltage is to change then a manual change to the solar charge controller's parameters is necessary.

Switching the solar charge controller from a 48 volt system to a 24 volt system is a good way to smoke the 24 volt system.

 

[timselectric]

Many solar charge controllers automatically determine the system voltage when they are first initialized and then never again automatically. In other words, it's determined once. If the system voltage is to change then a manual change to the solar charge controller's parameters is necessary.

Switching the solar charge controller from a 48 volt system to a 24 volt system is a good way to smoke the 24 volt system.

They are only wanting to switch the input, as I understand it.

 

[HRTKD]

They are only wanting to switch the input, as I understand it.

What the OP wants and what I understand may be two different things. A diagram of what the OP wants would be helpful.

 

[TheCoachStone]

What the OP wants and what I understand may be two different things. A diagram of what the OP wants would be helpful.

I just want to be able to easily hook this battery bank to the system when it is low on juice.

 

[HRTKD]

You have two different battery banks, correct?

 

[TheCoachStone]

You have two different battery banks, correct?

Yes sir

 

[timselectric]

I just want to be able to easily hook this battery bank to the system when it is low on juice.

Yes, that will work.

 

[chrisski]

The only caveat is the switch is not designed to switch banks under heavy load.

 

[timselectric]

The only caveat is the switch is not designed to switch banks under heavy luad.

I would agree with this.

Yes, that will work.

But, I would highly recommend putting a rated solar disconnect, ahead of this selector switch. And, on the 48v battery.

 

[Supervstech]

The only caveat is the switch is not designed to switch banks under heavy load.

I doubt there would be any load when switched. Since it seems he wants to switch off the solar when it isn’t putting out. And switch to the 48v bank. Likely won’t switch off the bank before either it is depleted or the 24V bank is full.
SCC’s don’t draw much when switched, they analyze the source for max draw.

 

[timselectric]

That makes perfect sense.

 

[TheCoachStone]

I would agree with this.

But, I would highly recommend putting a rated solar disconnect, ahead of this selector switch. And, on the 48v battery.

Is this different than the Blue Sea Battery Switch?

 

[timselectric]

Is this different than the Blue Sea Battery Switch?

Yes
But may not be needed, if you never switch positions on the blue sea under load.

 

[TheCoachStone]

Yes
But may not be needed, if you never switch positions on the blue sea under load.

I believe the switch will not go from 1 to 2 nor 2 to 1, so it has to go by OFF before switching. Is that what you mean?

 

[timselectric]

No
If switched to off, while a load is flowing through it. It can draw an arc. Which can set the switch on fire. If it's not rated for load switching.

 

[TheCoachStone]

No
If switched to off, while a load is flowing through it. It can draw an arc. Which can set the switch on fire. If it's not rated for load switching.

So, only switch it when there is no solar? If it were always done at night would I avoid this problem?