New poster trying to build a small solar system

I am wondering if I am making an mistakes with this plan: I am planning to purchase 2- 6 volt Duracell Golf Car Batteries - Group Size GC2, 20 amp hour rate:215 and connect in series. 2- RICH SOLAR 100 Watt 12 Volt Polycrystalline Solar Panels to be wired in series. 1- Victron SmartSolar MPPT 75/10 Solar Charge Controller 75V 10A with Bluetooth. My Camper has a Furrion 10 amp Solar Port Inlet that I would like to use to connect the Victron MPPT to the batteries. Will this work well ? If so, I would like to use 50 feet of wire to be able to move the panels 50 feet from the camper when needed. Thanks Guys

I looked up Duracell GC2 and there is a wet acid version and also an AGM version ? It matters. Are your camper batteries mounted outside on the tongue or in a compartment? Wet acid batteries have to be vented properly. Also 6 volt batteries have a high amp hour rating. But as you know it takes two to make 12volts. Consequently your camper, your car, your generator, and most everything is 12volt DC or 120volt AC. Just my opinion, I use 12 volt batteries. Less wire, less battery boxes, less connections, and transferable in emergencies.
I have purchased a Go Power GP-200, 200 watt portable solar system with a carrying case & a built in solar controller. It sets up and is weather proof.
I also purchased an accompanying GP extension cord with Anderson plugs to go with it. I will admit it is not as good a solar controller as the Victron.
But a nice portable set up like your describing.
Just an idea. You might also want two 12volt batteries. All this depends on your power usage.

I will be using the wet acid version. Batteries will be mounted outside on the tongue. Right, 2 - 6 volt batteries. Thank you for the Go Power GP-200 suggestion, I will take a look at that .. I was thinking about going with the Victron for the Bluetooth and a pretty decent price for an MPPT controller "I guess" …. They say Victron is good quality ? Everyone always tells me to use 2- 6 volts because of the thinker plates and true deep cycle and they are less than $90.00 each at Sams Club … ?? Thanks for the reply

You are correct, the batteries mounted on the tongue solves the ventilation problem and the 6 volts do have thick plates.
There are some excellent solar purposed 12volt batteries these days. However, costs / needs are important. Don’t forget 2 battery boxes and 2 additional heavy cables.
FYI; I have a friend who made contact with his wedding ring, a wrench and a deep cycle battery. The wrench & ring welded in place and he screamed until his ring finger and little finger burned off. I saw his hand and it makes a lasting impression.

The solar panels are nominal 12V but 22.1V open circuit (Voc). Wire in parallel unless the SCC accepts 24V.

I have heard both good & bad about Duracell. My preference is Trojan for about the same price.

I did find one battery box that supposed to hold two GC2 size batteries, but I may still go with two boxes .. Thanks for the tip on the dangers of the batteries … I have never been one to wear rings or jewelry and now my wedding ring wouldn't fit on these sausage fingers anyway lol …

Delmar said:

The solar panels are nominal 12V but 22.1V open circuit (Voc). Wire in parallel unless the SCC accepts 24V.

I have heard both good & bad about Duracell. My preference is Trojan for about the same price.

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I think the Victron will convert 24 volts "I'll double check" … I didn't know I could get comparable Trojan's for anywhere close to $100.00 a piece ?

Check to see what the maximum charge rate is for the batteries. It's possible that Your solar panels may at times charge the battery at a amp rating (watts) greater then the maximum C charge rate of the battery.

Robin said:

I am wondering if I am making an mistakes with this plan: I am planning to purchase 2- 6 volt Duracell Golf Car Batteries - Group Size GC2, 20 amp hour rate:215 and connect in series. 2- RICH SOLAR 100 Watt 12 Volt Polycrystalline Solar Panels to be wired in series. 1- Victron SmartSolar MPPT 75/10 Solar Charge Controller 75V 10A with Bluetooth. My Camper has a Furrion 10 amp Solar Port Inlet that I would like to use to connect the Victron MPPT to the batteries. Will this work well ? If so, I would like to use 50 feet of wire to be able to move the panels 50 feet from the camper when needed. Thanks Guys

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Hi Robin. With the information you provided, I'm going to make a bunch of assumptions in my attempt to help...

You are undersized in your solar panel array and solar charge controller (SCC) for the size battery bank you are proposing*.

If you adhere to the recommended 50% depth of discharge for lead acid batteries, your 215Ah 12V bank has 1,290Wh of usable stored energy (215Ah x 12V x .5). The Victron 75/10 has a nominal PV power rating of 145W. Assuming you achieve that full power (which is likely because you have 200W of solar panels), it would take 8.9 hours of full sun to completely recharge the battery bank. That's two full days to recharge if you weren't using any of that power for your devices/appliances.

* You haven't told us what you're trying to power with this setup, so it's difficult to say whether the battery bank is appropriately sized. If you share what you plan to power, members can provide better guidance on whether you are sizing the bank properly. Then we can size the array and SCC.

Speaking of the solar array and SCC: if we assume that you're sticking with the 215Ah battery bank, and that your location provides 4.5 hours of peak sun (you can check that using this website) you'll need 286.67W (1,290Wh/4.5h) from your array and SCC to fully recharge in a day (again assuming you aren't using any power while recharging). That basically translates to a 400W array since you generally de-rate the panels to 80% (400W x .8 = 320W). That puts you in the range of a 30A SCC.

Bottom line: Once you figure out how much power you need per day, you can do the math to figure out how big your battery bank, solar array, and SCC need to be to support your use cases.

I hope this helps.

Hello Dash & Bob,
I cant seem to find the maximum C charge rate of the battery online. I guess I will need to contact Duracell.
I really don't use that much power, I just mainly use the water pump, LED interior lights, the Fantastic Fan "some" and the propane furnace fan in winter. I do not need an inverter at this time. I have a generator for the wife's hairdryer and I know it will charge the batteries some but I always work around how low my battery gets. I don't think I will need more than 40% in 24 hours of what those two 6 volt Duracell Golf Car Batteries - Group Size GC2 will provide in 24 hours. I guess the best way for me to ask what I need is to just say I want those two batteries, I want a solar system to be able to recharge them from say 50% in a day of full sun, I would like to have the ability to place the panels "at least" 30' from the camper, I like the Victron charge controller because of the Bluetooth and being able to monitor the batteries, and I would like to use the Furrion Solar Port Inlet 10 amp that is already installed on the camper. I am open to any suggestions.
Thank you both for responding

Thanks for supplying more details. Here are more of my thoughts.

Robin said:

I guess the best way for me to ask what I need is to just say I want those two batteries,

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OK, so the 12V 215Ah battery bank at 50% depth of discharge gets you to the 1,290Wh I covered earlier.

Robin said:

I want a solar system to be able to recharge them from say 50% in a day of full sun

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If you're in an area that gets 4.5 hrs of peak sun a day, then going with my earlier calculations, you could likely achieve 1,440Wh from a 400W solar array (400W x .80 derate x 4.5 hrs). Since you say the panels will be 30-50 feet from the camper, will you be using portable ground mounts? That would allow you to do some manual tracking and help meet or exceed that number.

Since you already have a genny, you could use that to supplement on poor solar days.

Robin said:

I like the Victron charge controller because of the Bluetooth and being able to monitor the batteries

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If you are sticking with Victron, you'll need to go up to the SmartSolar 100/30 to be able to take advantage of 400W of panels. As a note, that one doesn't really leave you room to expand your array in the future. Not sure if you want to factor that in or not.

Robin said:

I would like to have the ability to place the panels "at least" 30' from the camper,

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That won't be a problem and you won't need big wires to accomplish it if you put your solar panels in series. You can use a voltage drop calculator to determine what size wire based on the panel array voltage and current, and the distance your array is from the SCC. You should aim for the typical target of a voltage drop of 3% or less.

Robin said:

I would like to use the Furrion Solar Port Inlet 10 amp that is already installed on the camper.

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That should work fine. Assuming you go with 400W of panels, and they are in series, and you stick with the Rich Solar, you'd only be sending about 5.5A max into that 10A port.

Bob has some good advice there. Just an FYI; I have a much bigger battery bank and I suspect a much bigger camper.
I did run several actual tests with the GP-200 watt portable. It can be set up to face the sun and the factory extension cord is thhn 12 awg with Anderson plugs. It consistently puts out 6.5 to 7.5 amps and up to 12 amps. It comes with a 30 amp PWM controller, no blue tooth. Also reading between the lines. You want a portable with extension cord in order to park the camper in the shade just like I did.
Yes I have a built in generator, but I will also say after trying it the 200w solar won’t keep up without running the generator. I am planing on mounting more solar panels on the roof and purchasing an additional Victron MPPT charge controller for the roof panels.
Just ideas from someone who has bought the stuff and tried it. I will say the GP-200w was always intended to be a supplemental power supply. It has a usb for cell phones & computers, cable clamps for my truck batteries or anything else. I’m not trying to sell you anything, just experience without the costs $...

Thank you Bob,
Just to educate myself, if I use the 100 watt Poly Panels with these specs.:

• Maximum Power(Pmax): 100W
• Maximum Power Voltage(Vmp): 18.2V
• Maximum Power Current(Imp): 5.49A
• Open Circuit Voltage(Voc): 22.1V
• Short Circuit Current(Isc): 5.86A
• Maximum System Voltage(Vmax): 600V DC
• Weight: 16.5 lbs
• Dimensions: 39.6 x 26.2 x 1.4 in

Would those 72.8 total volts for the 4 panels be too much for the Victron 75/10 to handle ? I must be misunderstanding the 75/10 meaning.

Thanks again,

Robin

Thank you Elevation for the much appreciated advice !!! We do not do a lot of camping without hookups but hoping to get out and do more soon … My thoughts originally were to just get a couple 100 watt panels and make a suitcase with them, when the generator was running in the mornings for the coffee pot and then hair dryer, it would be bulk charging the batteries, then maybe the panels would top them off during the day "or close" but as Bob advised, another 2 panels couldn't hurt and would get the job done. I went to Victron website and checked their MPPY calculator and see that it agrees with Bob on the 100/30 MPPT … I had the wrong idea on how it operated …. that's why I appreciate you guys so much !!!!!!!!

Thanks again,

Robin

Bob has some good advice there. Just an FYI; I have a much bigger battery bank and I suspect a much bigger camper.
I did run several actual tests with the GP-200 watt portable. It can be set up to face the sun and the factory extension cord is thhn 12 awg with Anderson plugs. It consistently puts out 6.5 to 7.5 amps and up to 12 amps. It comes with a 30 amp PWM controller, no blue tooth. Also reading between the lines. You want a portable with extension cord in order to park the camper in the shade just like I did. Yes I have a built in generator, but I will also say after trying it the 200w solar won’t keep up without running the generator. I am planing on mounting more solar panels on the roof and purchasing a Victron
Just ideas from someone who has bought the stuff and tried it. I will say the GP-200w was always intended to be a supplemental power supply. It has a usb for cell phones & computers, cable clamps for my truck batteries

Oops, I don’t know what caused that.

Robin said:

I will be using the wet acid version. Batteries will be mounted outside on the tongue. Right, 2 - 6 volt batteries. Thank you for the Go Power GP-200 suggestion, I will take a look at that .. I was thinking about going with the Victron for the Bluetooth and a pretty decent price for an MPPT controller "I guess" …. They say Victron is good quality ? Everyone always tells me to use 2- 6 volts because of the thinker plates and true deep cycle and they are less than $90.00 each at Sams Club … ?? Thanks for the reply

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I think that what you outlined will work fine its the same that I have used in one room solar house in Baja mx my duracell batteries are 8 years old will admit there about done good luck

Robin said:

I did find one battery box that supposed to hold two GC2 size batteries, but I may still go with two boxes .. Thanks for the tip on the dangers of the batteries … I have never been one to wear rings or jewelry and now my wedding ring wouldn't fit on these sausage fingers anyway lol …

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I have my LFP bank in a double CG2 6-volt battery box. DONT do it. Can you say heavy? at least 124 Lbs. A big advantage is it's 2 pieces.
Good luck with your project!

Robin said:

Hello Dash & Bob,
I cant seem to find the maximum C charge rate of the battery online. I guess I will need to contact Duracell.
I really don't use that much power, I just mainly use the water pump, LED interior lights, the Fantastic Fan "some" and the propane furnace fan in winter. I do not need an inverter at this time. I have a generator for the wife's hairdryer and I know it will charge the batteries some but I always work around how low my battery gets. I don't think I will need more than 40% in 24 hours of what those two 6 volt Duracell Golf Car Batteries - Group Size GC2 will provide in 24 hours. I guess the best way for me to ask what I need is to just say I want those two batteries, I want a solar system to be able to recharge them from say 50% in a day of full sun, I would like to have the ability to place the panels "at least" 30' from the camper, I like the Victron charge controller because of the Bluetooth and being able to monitor the batteries, and I would like to use the Furrion Solar Port Inlet 10 amp that is already installed on the camper. I am open to any suggestions.
Thank you both for responding

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Generally lead-acid the recommended limit on charging is no more then 20-25% in amps of AH number. 220 AH typical golf cart battery would be about 45-55 amps max charge rate. AGM's can be charged at a bit higher rate. In reality, up to about 13.8v charging you can charge lead-acid at higher rate. That is close to voltage they start to bubble a lot and you have to limit current beyond that point.

For any large battery, need to be cautious with wrenches and such around battery terminals Vented flooded lead-acid can vent hydrogen gas during charging (bubbling sound) so you don't want that building up in an RV compartment. The bubbling is water in electrolyte being split up into oxygen and hydrogen. You want to be sure you have relatively easy access to add water periodically. AGM's hold gases in and recombine most of it but have a safety vent if pressure gets too high. I don't recommend floaded lead-acid for RV's. Too much mess and battery acid drops on metal is not good.

Daniel todos said:

I think that what you outlined will work fine its the same that I have used in one room solar house in Baja mx my duracell batteries are 8 years old will admit there about done good luck

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Thank you !