Charge controller

[$teeve]

Hi
I'm new to this site and to solar tech in general so I hope I don't ask t many stupid questions ..lol
This would be for my trailer , just want the 12v system for now .
I have two 350w panels for total of 700w of power and 2 six volt deep cycle batteries ( costco ) with 200ah ..
What size and type of charge controller would ou guys recommend or do I need actually..
Thank you

 

[DThames]

Hi
I'm new to this site and to solar tech in general so I hope I don't ask t many stupid questions ..lol
This would be for my trailer , just want the 12v system for now .
I have two 350w panels for total of 700w of power and 2 six volt deep cycle batteries ( costco ) with 200ah ..
What size and type of charge controller would ou guys recommend or do I need actually..
Thank you

Would it be correct to assume that you don't have space nor plans for more panels (someday)?

 

[$teeve]

In the future maybe ..
Basicly, trailer is in an area with no electricity and we use it as weekend get away and would like to keep my fridge on all week wile we are not there..
It's propane but it need electricity..
Basically use the 12v system on trailer like lights , pump , radio ect when there ..
Make sense or am I not making any..lol

 

[DThames]

In the future maybe ..
Basicly, trailer is in an area with no electricity and we use it as weekend get away and would like to keep my fridge on all week wile we are not there..
It's propane but it need electricity..
Basically use the 12v system on trailer like lights , pump , radio ect when there ..
Make sense or am I not making any..lol

A charge controller will be rated to charge at some X amps. A 50amp 12v charger would work okay for 700w of panels. The best 700w of panels could do at a charging volts of 14v would be about 50 amps and that would be for a short time on a perfect day. However, if you were to say, "Someday I want to put up 4 more panels at the site where I normally camp......" you might want to buy a larger charger. That is why I ask if 700w is your fixed max.

 

[$teeve]

Oh Ok, I know not enough charger is bad but having larger then needed has no effects ..
I'm assuming having and inverter is useless with the panels and batteries I have ?
Would need more of both ??
Not trying to build a 10k system but would be nice to watch TV or run mini electric fridge kinda thing..lol
Very new to this and doing research online ect ect..
Lots of info ..lol
Thank you so much for the help..

 

[DThames]

You can get a 60amp or 100amp charger but with larger sizes come costs and physical size. That is not a bad thing because a 100amp charger would have less issues dumping its heat than a 50amp if both were running (say) 45amps. I like the EPEver AN series but I am not an RV person and there might be better units for RV use, where mounting location/orientation and air flow would be a concern. The EPEver AN needs to be vertically wall mounted for proper cooling.

A 1000w inverter or even a 500w would allow you to watch TV and other lite AC loads. No reason not to have one. Do you use a generator while camping? If you have a generator for heavier AC loads, coffee maker, microwave, etc, you could get by with a small inverter as mentioned above.

 

[$teeve]

Ya I do have a 2200 w Gen.. I've been using it to charge my batteries when there and when needed .. Not great but this is why the questions to improve..lol
Would a 1000w inverter run a small mini fridge constantly threw a weekend ?
One more question and by the way , you've been extremely helpful..
Is 700w of solar enough to charge those batteries all week when not there with propane fridge running ???
Thanks again, awesome..

 

[DThames]

A 1000w inverter (pure sine wave type) should run a mini-frig without issue. It is the batteries that get into the "how long" question. You need to know the power needed by the frig over the period of time. This will vary with many factors including the weather. Next you need to know how many hours the battery will provide that power, how fast they can be charged with good sun, how slowly they will charge with less sun....etc.

Where do you camp (like zip code) and in what months of the year? That information can be put into a solar power calculator that will estimate what power you can really get from your panels.....on average.

 

[Tim Tim]

Ya I do have a 2200 w Gen.. I've been using it to charge my batteries when there and when needed .. Not great but this is why the questions to improve..lol
Would a 1000w inverter run a small mini fridge constantly threw a weekend ?
One more question and by the way , you've been extremely helpful..
Is 700w of solar enough to charge those batteries all week when not there with propane fridge running ???
Thanks again, awesome..

Ok what you first need to look at is your power consumption as you want to run your fridge all week. Is it a 3 way fridge? What is the power consumption on 12v? i think it will be way more than your battery is capable of providing. it would be more economical to run it on gas.

 

[$teeve]

Yes that's what I'm doing is running on propane mode but it needs electricity for fan apparently..
Very little I was told .
Thats what I would run all week and start the electric mini only on weekend when there..
I'm getting a solid 5 + hours of sun a day this time of year..
Thanks for the info , lots to take in and process ..lol

 

[Tim Tim]

Plenty of people here to help you but what your will need to work out is your power consumption or as some would say you need to do a power audit.

List the appliances that you will be using, the wattage and the length of time you will be using them. That way we can work out your total power consumption.

 

[$teeve]

Ok I'll do that this weekend and get back to you or post it..
Thanks again so much ..

 

[HRTKD]

Ya I do have a 2200 w Gen.. I've been using it to charge my batteries when there and when needed .. Not great but this is why the questions to improve..lol
Would a 1000w inverter run a small mini fridge constantly threw a weekend ?
One more question and by the way , you've been extremely helpful..
Is 700w of solar enough to charge those batteries all week when not there with propane fridge running ???
Thanks again, awesome..

I charge my 560 Ah of LiFePO4 batteries with 640 watts of PV on the roof of my RV. It works well. As long as I have sun I don't worry about power.

The mini fridge will consume a lot more power than the propane absorption fridge. A 1000 watt inverter might run it. You need to know how much power the fridge draws (hence the questions about power consumption in the prior posts). Don't guess at this stuff or you'll be spending more money replacing devices that weren't big enough. But the fridge probably will want a pure sine wave inverter not a modified sine wave inverter. Most of the less expensive inverters are modified sine wave.

Also, the inverter produces heat. Can your RV handle the heat that the inverter will produce?

 

[Tim Tim]

Ok lets start off with the make and model of your existing fridge because on gas they don't generally have a seperate fan when run on propane. I’m in Australia and yes sometimes we install fans to provide ventilation to reduce the heat but they are not critical to the fridge.

Ok the mini fridge is it 12v in which case you will not need an inverter for that but you will need to know the power consumption. If it is 110v then you will need an inverter but again the size will depend on your power consumption and we will need to look at whether you may be using a number of 110v appliances at the same time. I’m assuming you use 110v over there as we use 240v.

The same with the tv. Is the TV 12 volt or is it 110v. Find out the wattage and how many hours you will be running it for. Same with the lights. I take it that they will be LED.

 

[$teeve]

I'm gonna take inventory of all that this weekend ..
This all started with this guy selling me a bluetti ac200p with 700w of panels..
More then enough power he says but the problem was the unit would shut off when we were no there and you have to manually turn it back on ..
Would get back on the weekend and unit was charged but nothing working.
Plus the unit took like 40% of its available power with no load , just to run..
Got my money back , thank God. Lol

 

[$teeve]

Hi again
So I've looked at everything this weekend and need advice..
All I want is to run this suff on weekends when I'm there , so 2-3 days ..
-First pic is my panels x2
-Second is mini fridge
-Third is coffee maker , 10 min in morning .
So correct meif I'm wrong please.
I was thinking a 60 amp charge controller , a 200 ah lithium battery and a 3000w inverter .. Am I wrong ,not enough ??

 

[HRTKD]

Yeah, that'll work. I was running my coffee maker with similar specs off of a 1000 watt (modified sine wave) inverter and two 6 volt batteries. I never tripped the inverter. I used a 170 watt panel with a 10 amp PWM controller. That's my old/first system.

The refrigerator could have surge amps much higher than the label says the amps are. But with a 3000 watt inverter you should be able to handle it just fine.

 

[$teeve]

And the 200 ah lithium battery is enough to run all that for few days ?
Solar would charge things back up in afternoon ..
How many watts or amp per hour would that fridge use on all day ?

 

[HRTKD]

And the 200 ah lithium battery is enough to run all that for few days ?
Solar would charge things back up in afternoon ..
How many watts or amp per hour would that fridge use on all day ?

The better question is, "Will the BMS on the LiFePO4 battery support the amp draw?" You have enough Ah to last for a couple days without solar. Solar adds more days.

.8 amps x 120 volts AC = 96 watts

96 watts / 12 volts / 90% efficiency of the inverter = 8.88 amps
(12 volts is a worst case number. Your LiFePO4 battery will live most of its life at 13 volts or higher. At 13 volts the amp draw is lower.)

8.88 amps x 24 hours = 213 Ah. Oh no! This is more than your battery Ah!

But that doesn't tell the whole story. The refrigerator doesn't run the entire time. It's duty cycle may be only 50%, so your draw on the batteries would be maybe 105 Ah. But you have solar and enough to satisfy the draw of the refrigerator and charge the batteries.

To answer the question above, the BMS on your LiFePO4 battery should be able to easily handle a surge from that refrigerator as long as the BMS is rated for 100 amps.

Here is a link to a nice writeup on how to figure out Ah, watts and details on the calculations I used.

Amps, Amp-hours, Watts !! what's that all about?

 

[$teeve]

Wow ok thanks , great very helpfull ..
Worse case get another battery I guess.

 

[$teeve]

Also , I was looking at renogy charge controller and inverter , any good for the price point ? Or stay away ?

 

[HRTKD]

Also , I was looking at renogy charge controller and inverter , any good for the price point ? Or stay away ?

I'm not a fan of Renogy products. Victron Energy is expensive, but the warranty and reliability are better. I try to buy from an actual supplier, not Amazon. If you need help, Amazon isn't going to be there. The supplier will. Discounts on Victron products are hard to come by so the price you find on Amazon isn't going to be much different from other sites. I used Solar Supply House. The guy on the phone knew exactly what I was designing and offered a small change that saved me some money.

The Victron Multiplus 12/3000 is what I have. It's rated for 2400 watts despite what the product name says. The 3000 refers to volt amps, not watts.

 

[$teeve]

Thanks

 

[Tim Tim]

Thanks

Great I see HRTKD has been helping you.

I think your fridge will have a cycle of less than 50% but you can always test it out if you have a watt meter.

Victron are top of the range and pricey. Although I have some Victron things I have an EPEver solar controller and Giandel inverter. Choose a slightly higher wattage inverter than your highest appliance or take into consideration any other appliances you are going to use.

A 200Ah lithium battery appears to be ample but worst case you just add another.

 

[$teeve]

Great I see HRTKD has been helping you.

I think your fridge will have a cycle of less than 50% but you can always test it out if you have a watt meter.

Victron are top of the range and pricey. Although I have some Victron things I have an EPEver solar controller and Giandel inverter. Choose a slightly higher wattage inverter than your highest appliance or take into consideration any other appliances you are going to use.

A 200Ah lithium battery appears to be ample but worst case you just add another.

Ya I've decided to do it right an go wit the victron , great reviews ..
The 60 amp charger from what I can see holds 6 awg wire max.
Do I need Tha big a wire , they say yes ..lol