Simple set up for camper trailer

[Aharry]

Hi All,

The family have recently gone from a caravan to a camper trailer to allow us to venture to more camp sites. I'm looking for a cost effective off grid solar solution and appreciate any advice from this forum. The camper has 2 x 100Ah AGM batteries and 1000W inverter. The main draw is a fridge/freezer @ approx. 3.2 A/H plus fans, lights, water pump and phone charging.

The original thought was attaching solar to the boat rack however the more I contemplate the idea I'm moving away. The current plan is to make some folding solar arrays (2P each) so I can chase the sun without having to park the camper in the sun on warmer months. I was looking to use the below gear

• 4 x 100W renogy panels - two 100W solar panels in series as a group and connect two groups of 200W solar panels in parallel.
• Rover 40A MPPT Controller with blue tooth module added to help monitor
• 8AWG - Cable run between panels and camper would be 20ft
• 2x 10A MC4 fuse
• 1x 40A ANL fuse

Is this a decent starting set up to keep us powered up when off grid?

Also, not sure if this is best tackled at the same time....I am told I need a DCDC charger between the anderson plug and camper battery for towing. The fridge doesnt get full power and the camper battery doesnt really charge when towing. Not sure if I should be fixing this within my solar solution - HELP PLEASE?

Thanks,
AHARRY

 

[12VoltInstalls]

I think what you are planning is great!
But you need to know if it will also work.

The main draw is a fridge/freezer @ approx. 3.2 A/H plus fans, lights, water pump and phone charging.

Is that fridge a propane/120VAC fridge? Or straight electric? I am assuming 3.2Ah is at 120V??? (Wattage is more useful, watt hours even better)

looking to use the below gear

• 4 x 100W renogy panels - two 100W solar panels in series as a group and connect two groups of 200W solar panels in parallel.

Referred to as 2S2P - this is a useful setup
Maybe about 2kWh/day in good sun.

Need to know the fridge info (above); 3.2Ah without volts or duty cycle (hours/day; aka watt hours) but assuming 120V and continuous: THAT alone is 400W/hour and your panels will probably be in the 300-350Wh/hr range, less 15% for the inverter conversion inefficiency leaving you short by 33% for the fridge alone. If the fridge can run on propane that would solve that…
But my assumptions are likely wrong without further information.

Is this a decent starting set up to keep us powered up when off grid?

Is the inverter a pure sine wave inverter? Or modified sine wave? IMHO you need a pure sine wave inverter.

Yes, that is a decent starting setup. However, without the watt hours of the fridge and other loads one cannot affirm that will, “keep us powered up when off grid.”

I have a lot of other suggestions to share but let’s get the numbers for your needs and myself and probably others can then give useful advice and not just opinions or guesses.

 

[Aharry]

I think what you are planning is great!
But you need to know if it will also work.

Is that fridge a propane/120VAC fridge? Or straight electric? I am assuming 3.2Ah is at 120V??? (Wattage is more useful, watt hours even better)

Referred to as 2S2P - this is a useful setup
Maybe about 2kWh/day in good sun.

Need to know the fridge info (above); 3.2Ah without volts or duty cycle (hours/day; aka watt hours) but assuming 120V and continuous: THAT alone is 400W/hour and your panels will probably be in the 300-350Wh/hr range, less 15% for the inverter conversion inefficiency leaving you short by 33% for the fridge alone. If the fridge can run on propane that would solve that…
But my assumptions are likely wrong without further information.

Is the inverter a pure sine wave inverter? Or modified sine wave? IMHO you need a pure sine wave inverter.

Yes, that is a decent starting setup. However, without the watt hours of the fridge and other loads one cannot affirm that will, “keep us powered up when off grid.”

I have a lot of other suggestions to share but let’s get the numbers for your needs and myself and probably others can then give useful advice and not just opinions or guesses.

Thanks for the reply. Hopefully the information below helps fill in the gaps from my original message.

The fridge will be running on 12V DC so I think the product information of 3.2 Ah converts to about 40Wh. I'm sure it will be higher with the children constantly opening the camp fridge looking for the next snack.

The inverter in the original set up is a cheaper modified sine wave which I will be looking to upgrade at some point so we can enjoy the occasional morning coffee while camping. Happy for any tips on good inverters.

I found this on the Renogy site ...Renogy 12V 50Amp DC to DC Dual Battery Charger With MPPT...which may fix my 'camper battery charging while towing' issue and let me feed the portable solar in efficiently when camping.

DCC50S 12V 50A Dual Input DC to DC Battery Charger with MPPT

Renogy 12V 50A MPPT DC to DC Battery Charger 12V Car Battery Charger On-Board Charger, for Alternator and Solar Panel, Charger for Flooded, Gel, AGM, and Lithium Batteries, Using Multi-Stage Charging, in RVs, Cars, Boats, Yachts. Order yours Now.

au.renogy.com

The end goal is a lithium battery set up. For now I'm trying to ensure we stayed powered for 3-4 day camping trips to make the experience comfortable for the family.

 

[chrisski]

The fridge will be running on 12V DC so I think the product information of 3.2 Ah converts to about 40Wh. I'm sure it will be higher with the children constantly opening the camp fridge looking for the next snack

I think you have a 40 watt fridge which will draw 480 watt hours if it cycles on half the time. If its cooler it’ll be less and warmer it’ll be more. Watt hours matter for battery size. if you assume 12 volt battery with a 3.2 amp draw, that‘s 32.8 amp hours, but again could be much more or much less depending on how it’s actually on.

I found this on the Renogy site ...Renogy 12V 50Amp DC to DC Dual Battery Charger With MPPT...which may fix my 'camper battery charging while towing' issue and let me feed the portable solar in efficiently when camping

That could be your answer. I do not have that, but others have said it will charge up to 50 amps. 50 amps exceeds the 13% of the 20 hour rating I can charge my FLA batteries with. I can only charge 200 ah of lead acid at 13%. Please check your AGM specs for the max charging rate. That rate could be more Than 50, but you don’t want to exceed whatever that rate is.

The max charging rate is also something to watch when adding panels. With the ground portable lion energy panels I have, 400 watts of panels could push the limits for my lead acid batteries. I use 6 charging to a 12 volt battery amps as a rule of thumb on one of those 100 watt panels, but they have briefly pushed 7 amps. After you have those panels installed you’ll get a good feel for how much they will actually produce. I have renogy roof panels, but in the flat configuration, they only make 4 amps per panel tops, and rarely that.

 

[HRTKD]

A 2s2p PV array doesn't need a fuse between the parallel strings. An easily accessed circuit breaker prior to the MPPT is handy for shutting off power to the MPPT for those times when you need to work on the system.

The 40 amp fuse is too small. I'm assuming that this will be on the output side of the MPPT. If the MPPT ever hits maximum production, the fuse could blow. Size the fuse at 1.25 times the maximum expected output to prevent nuisance trips. Many of us are using a circuit breaker in that position as it makes it easier to shut down the MPPT with a breaker. I use the Blue Sea Series 187 breaker.

 

[Aharry]

Thanks again for the great advice.
My car has a smart alternator and I'd like to install the dcdc charger next to the camper batteries. Camper has a 7 pin flat connector car has 12 pin. To hook up to the car and keep dcdc charger working I'm looking at either
1) changing the camper trailer plug to 12 pin with ignition wire linking to dcdc and a separate 2 pin anderson connection for battery charging or
2) using a three pin Anderson plug with ignition wire included or
3) something better you guys suggest

Aharry

 

[12VoltInstalls]

The ignition-on sense should already be in your vehicle connector. So you only should need the higher amp + and -

 

[grizzzman]

Thanks again for the great advice.
My car has a smart alternator and I'd like to install the dcdc charger next to the camper batteries. Camper has a 7 pin flat connector car has 12 pin. To hook up to the car and keep dcdc charger working I'm looking at either
1) changing the camper trailer plug to 12 pin with ignition wire linking to dcdc and a separate 2 pin anderson connection for battery charging or
2) using a three pin Anderson plug with ignition wire included or
3) something better you guys suggest

Aharry

I would suggest that you disconnect the charge wire from the 7 way trailer side plug.( normally there is a junction box that you can disconnect there) and use it to trigger the DC to DC charger. Good luck with you smart alternator. My 40 amp DC to DC would output in the low 30s amps due to the battery voltage being 12.6 to 12.9 most of the time. I have researched a way to defeat smart charging when i need it.

 

[HRTKD]

I've never seen a 12 pin connection on a vehicle that had the usual turn/brake/reverse signals and certainly never a 7 pin flat. Is that a European thing? My F-350 has a 12 pin but it's for the trailer camera and TPMS. The regular 7 pin round has all the important stuff.

The power from the tow vehicle is often limited to 30 amps by fuse and relay.

 

[12VoltInstalls]

I’ve never seen a 7wayFlat but probably Eu

The 12-pin I thought was just military but I guess I’m wrong

 

[grizzzman]

There is a round pin 7 way "semi" style plug. There is a 7 way "RV" flat pin style plug. This is US stuff. The OP was planning on installing the DC to DC charger on the trailer. My suggestion was to use the charge wire to control the DC to DC charger. Not charge from it.
I am unsure about the 12 pin though.

 

[grizzzman]

It appears over seas. The 12 pin.

Standard Wiring for 12 Pin Trailer Plug​

Although there are several options for how to wire up a 12 pin trailer plug, we usually recommend the following configuration.

1. Left indicator
2. Reverse
3. Earth
4. Right indicator
5. Electronic Brakes
6. Brake lights
7. Park lights
8. Isolated power supply (For Fridge or Accessories)
9. Isolated power supply (For Fridge or Accessories)
10. Earth
11. Spare
12. Isolated power supply (For Fridge or Accessories)

In most cases we will also install an Anderson plug or two depending on the vehicle and caravan.

• Grey Anderson plug: Isolated Charge feed from vehicle start battery.
• Red Anderson plug: Direct 12v supply suit ESC Operations.

 

[KTM-Guy]

Are you mostly going to be using the camper for 3-4 days in one spot? Or will you camp a day or two then drive 2-4 hours to your next spot?

If 3-4 days in one spot the dc2dc will not offer much. You can fully charge at home with AC, then live off the solar while camping. If you do go with a dc2dc make sure you size the wire for the amps your dc2dc puts out. The stock wiring with your vehicle is not big enough.

I have two batteries, one in the camper, and one in our Jeep. The Jeep battery is just to run our fridge/freezer. About 50AH a day depending on ambient temperature. The dc2dc charger is just for the Jeep. We can go about 4 days without running the Jeep. But we never stay in one spot for very long. If we do the camper stays and we take the Jeep.

The battery in the trailer should (still testing) last 5-7 days. If we are camping that long we will get a campsite with AC for a night and charge with the 30amp charger we will carry.

Todd

 

[12VoltInstalls]

There is a round pin 7 way "semi" style plug. There is a 7 way "RV" flat pin style plug

Right. But flat and round are usually referring to the connector shape.

A four-way-flat has round pins but is a flat connector.
An RV cord or a utility trailer cord, a few tractor-trailer cord plug types is 7-way round but the contacts are spades. FWIW an RV cord and a utility trailer cord have different wire color and positioning conventions for reasons nobody has ever explained to me. Just is that way.

The standard industry nomenclature is what I was referring to. Flat connectors, round connectors.

 

[Aharry]

Thanks, there's a lot of good information above to digest. I'm in Australia and the flat 7 pin & 12 pin connectors are standard here. We sometimes go away for a week to one place other times we might travel for a fortnight stopping in each place for 2-3 days.

The current solution I'm leaning towards is:

• Controlling the DCDC through the flat connector to overcome the cars smart alternator issue. The car already has 12 pin connector so I will change the trailer from 7 to 12 pin connector and use one of the spare 12V supplies for DCDC control
• Installing the DCDC next to the trailer batteries and charging through standard Anderson plug from car when towing to withstand the amps (12 pin connectors are only good for 35A)
• Using DCDC charger with MPPT and having an Anderson plug connection at the back of the trailer for solar input.
• Building folding solar using 4 x 100W panels, 2S2P, with a 30ft lead for chasing the sun. The vehicle will be disconnected from the trailer usually when camping so the solar panels could plug into either Anderson plug at the front or rear of the trailer.

I cant justify changing to lithium batteries yet when the trailer comes with new AGM's but hopefully in future I can change to lithium.

Aharry

 

[Levo]

Thanks again for the great advice.
My car has a smart alternator and I'd like to install the dcdc charger next to the camper batteries. Camper has a 7 pin flat connector car has 12 pin. To hook up to the car and keep dcdc charger working I'm looking at either
1) changing the camper trailer plug to 12 pin with ignition wire linking to dcdc and a separate 2 pin anderson connection for battery charging or
2) using a three pin Anderson plug with ignition wire included or
3) something better you guys suggest

Aharry

1) Like yourself (and per Renogy's recommendation), I want to install my DC-DC 40A in the caravan by the house battery; so a 2 pin Anderson plug (say 50A) to connect to the truck.
2) So is there a 3-pin Anderson plug?
3) I am considering powering the ignition wire (and the current halving function) from the caravan 12v system controlled with a wireless remote switch. I think that would work, no extra wires and switchable from the truck.

433Mhz Wireless RF Switch, DC 12V 1CH Channel Long Range Wireless Remote Control Switch Relay Receiver Module, Transmitter Toggle Switch RF Relay (2 Transmitter & 2 Receiver) : Amazon.ca: Tools & Home Improvement

433Mhz Wireless RF Switch, DC 12V 1CH Channel Long Range Wireless Remote Control Switch Relay Receiver Module, Transmitter Toggle Switch RF Relay (2 Transmitter & 2 Receiver) : Amazon.ca: Tools & Home Improvement

www.amazon.ca