Thrown fridge into cabin mix, wondering about system configuration and efficiency

Get everything off the Load Terminal, and take power directly from the battery.

OK a 20 Amp MPPT Controller maximum input power vs battery voltage:

200 watts @ 12 volt battery.
400 watts @ 24 volt battery.

You already have a 130 watt panel which means you are pretty much stuck with using the same model panel for expansions, and at 260 watts of panels does not gain you much as anything over 200 will be clipped off. So to add a panel, it would be wise to upgrade the controller and make sure the replacement Controller can handle wiring two panels in series. I have no clue where you came up with 320 watts, but will not work with your 20 amp controller.

As for the batteries, keep them for now to learn how not to kill your new set of batteries down the road.

As for drain on the batteries has been answered in 2 diferent threads today. Not going though it a 3rd time. This post, replies 4&5.

Original plan, before I pursued this other train of thought, was to remove the 130W and 20A MPPT and replace with a 320W panel and 40A MPPT. I'll use the 130W panel elsewhere or store it for later projects.

You can use the load terminal for the timing functions of the cc but you should run any devices through relays.

The new thinking is:

* Keep the 130W panel and 20A CC LED unit in place on/in the cabin.

* Install the new 320W panel and 40A MPPT LCD unit.

* Change out the old silver calciums for the two new T105REs (the old ones will be used somewhere else).

* Connect both set ups to the battery bank separately. I've read a lot about this being done successfully, i.e. using two MPPTs with their own separate panels.

* Use all loads straight from battery bank, as said by Sunking.

* Use a 12V timer switch to run the 12V fridge during daylight hours.

Wondering if the small 20A and bigger 40A MPPTs joined to the batts will cause interference?

From what I've read about multiple MPPTs being used (like in Mike's setup, which he mentions frequently), there shouldn't be any problems.

Hi I just want to know , what's best Inveter to use to run a hotplate of 1200W for 5 hours on a 24V system and two batteries @ at 200AH plz

Hi Kaduyuizo, and welcome to the forum. Yes, we are all fine thanks.

So, um, what does your question have to do with my fridge?

And another 'so, um...'

Lol, you're kidding, right?

Short answer, USE GAS.

Longer answer: let's assume this is an off-grid system. If it is grid tied, use the grid!!

1200W * 5 hrs = 6000 watt hours

For that, you will need the following 24V system, taking into consideration inverter losses (and a lowest insolation of 2.5 hours):

* 862 Ah battery bank
* 4200 watt panel array
* two the biggest charge controllers you can get, i.e. 90 or 100A units (do these even exist? 80A is the biggest I've seen).

On a 48V system:

* 430 Ah battery bank
* same panel array
* one charge controller at 90 or100A

This is a 3 day battery bank, i.e. if the sun shines today and it is very cloudy for the next 2 days you will have to stop cooking and when its sunny again you will have to wait for the batteries to charge again, which will take a while.

But to really answer your question, a true sine wave inverter with a capacity bigger than 1200W! But with your batteries, all you'd have is a short stint of cooking before those batteries drop below 70 or 60% and then they will not last you long.

FYI...He is a new member and new members are not allowed to start a new thread so they find someone else's to hijack.

Okay, thanks, didn't know that.

Unfortunately a 24v 200Ah battery can safely provide about 1200 wh a day (24v x 200Ah x .25 = 1200Wh). So your hotplate may work for about 1 hour or less.

You would have to increase the size of your battery system by 5 times to maybe run your load.

I'm so great full for the knowledge plz now that I may use 4 batteries 2 in series and 2 pairs in parallel to make it 24V hope its OK for 4hrs

However you wire your batteries together you need to create a 24volt 1000Ah system. I am not sure how you are going to get that with 4 x 12volt batteries.