Solar Freezer

[dgdistrb]

Hi Guys, I am confused with the benefits of 24v vs 12V. I have a solar freezer that I currently have hooked up for 12v.
It will run on 24V also.
I would like to go 24v with the system if the advantages are there.
I would hook my 2 150W 12v panels in series.
Hook my 4 78 AHR 12V batteries in series.
My 2 questions are:
Do I need to put a fuse between the panels and Charge controller?
And between the batteries and the freezer? (The freezer automatically detects whether 12v or 24v is coming into the freezer and adjusts its self)
Also do I loose amp hrs capacity because the batteries are hooked in series?

Thank you!

[Sunking]

Hi Guys, I am confused with the benefits of 24v vs 12V.

Efficiency and economics. Higher voltage is always better.

Do I need to put a fuse between the panels and Charge controller?

No unless you have 3 or more parallel strings of panels. Series and higher voltage mean a lot less and smaller wire and no extra hardware like fuses and combiners.

And between the batteries and the freezer?

Yes fuses go between the Battery and Load, and Battery and Controller. Both are installed directly on the Battery Term Post.

Also do I loose amp hrs capacity because the batteries are hooked in series?

That was 3 QUESTIONS. No wonder you are confused, you cannot count.

Yes you loose half, but it is no loss, its a gain in the end. Amp Hours mean nothing without a voltage. You want top know energy, AH don't mean squat. You are going from 12 volts @ 156 AH to 24 volts @ 78 AH. Both are exactly equal.

12 volts x 156 AH = 1872 Watt Hours
24 volts x 78 AH = 1872 Watt Hours.

Example if the freezer used 100 watts, at 12 volts pulls 8 amps from the battery. At 24 volts pulls 4 amps. At 4 amps you gain 400% efficiency over 12 volt wiring. In other words less loss means more usable energy from moving from a lower to higher voltage.

If you understand this very simple formula you would have understood from the beginning.

Watts (aka Power) = Volts x Amps

1 volt x 100 amps = 100 watts
100 volts x 1 amp = 100 watts.

Watt Hours = Watts x Hours

For a Battery Watt Hours = Battery Voltage x Amp Hours.

So what does Amp Hours mean? Absolutely nothing other than Amps over a period of time.

[dgdistrb]

Damn SunKing, You gave me a lot of information in that reply. You are right, If I had that info earlier I would not have had to ask.
Well you have me excited and I cant wait to make the conversion. Once I get that done I'm going to convert the cabin from 12v to 24v.
Thank you very, very, much for your time and help!

OH! Question #5
Can I stay with my current 30 amp cartridge fuse between the panels and CC?

[dgdistrb]

No I'm sorry about that last question. Can I put that fuse between the Battery and freezer? LOL

[Mike90250]

This is the sort of fuse need at the battery, one is a 30A for the controllers 10 ga wires, and the other is ___ A for the freezer.
This is the company that makes them https://www.bluesea.com/products/215...k_-_30_to_300A


MRBF_dual.png

[dgdistrb]

Thank you for that link. I will check them out!

[OldBat]

One tiny thing that has been missed. You currently have four 12 Volt batteries in parallel and plan to go to 24 volts. You state "Hook my 4 78 AHR 12V batteries in series." This would take you to 48 volts. You need series/parallel so two banks of two batteries.

[dgdistrb]

Yes OldBat thanks for pointing that out.
It looks like with the link Mike90250 sent me and all the info SunKing gave me, I'm all set.
All you guys have been a great help!
Thank you!

[Mike90250]

Just be sure your wires are rated for the amps the fuse allows, you don't want the wire to heat and melt in case of a fault.

[dgdistrb]

Thank you Mike. I will make sure.
Have a nice holiday today!

[dgdistrb]

I found the fuse holder and fuse here at Dell City. This is the cheapest place I found.

https://www.delcity.net/store/Marine-Rated-Battery-Fuses/p_808921.h_808922

https://www.delcity.net/store/Battery-Fuse-Block-!-Marine-Rated/p_808937.h_808939