Planning Power Needs for One Week Trip

[bikelanta]

Pre-emptive commentary: I will be building a better full-time electrical setup into our Super Pacific once it is ready but for now I'm trying to deal with an assembly of random parts to meet some short term needs.

All components discussed in this thread are linked below the narrative.

I'm thinking through my plan for maintaining power for our family during a week long trip later this year to some national parks. Our primary power needs are a CPAP machine and an ARB fridge. The campgrounds at which we are staying do not have shore power connections. Our Power Wagon has a 400 watt power outlet in the truck bed. While driving, my plan is to plug both the Goal Zero and the Schumacher automotive battery charger (connected to the Group 31) into a power strip that is plugged into the 400W outlet to maintain charge in both batteries. The fridge is then connected into the Group 31 battery using an ARB style plug. When we stop, the battery will power the fridge and while driving, the charger will charge the battery. The Goal Zero gets used exclusively for the CPAP machine at night. I've generally found that I can really only get 2 nights, maybe 3 out of the GZ for the CPAP, so I don't connect the fridge into it. I've also found that the fridge can run 3-4 days (maybe more, but haven't tested) running off the Group 31 battery without a charge.

During this trip, we'll be exploring national parks (Yellowstone/Grand Teton) during the day, so the truck will get driven and thus the bed outlet will prove helpful. I also have solar panels that can be leveraged, if it makes sense to do so. The panels can either be connected directly to the Goal Zero, which has a built in solar controller, or through a simple Renogy Solar Controller and then connected to the Group 31. The panels are not attached to the truck, so would largely only see use at the campground, assuming there is any decent sun.

My questions:

1. Any reason that I shouldn't use the power strip in the bed outlet, assuming we stay below 400W?
2. Any reason that I shouldn't use the Schumacher 15A automative charger to charge the Group 31 battery while on the move? (Edit: it has a 3A output setting in addition to the 15A rapid charge.)
3. Does the 400W outlet seem sufficient that we wouldn't necessarily need the solar panels?
   1. Drive time to Teton is 8 hours (probably 10 with stops)
   2. Drive time from Teton to Yellowstone campground with stop is about 3 hours, maybe more with stops
   3. Projecting 1-2 hours of driving each day while at parks, just to be out exploring
4. What am I missing?

Batteries
Goal Zero Yeti 400 with 35Ah replacement Duracell battery (originally 33Ah)
Duracell Group 31 Deep Cycle 105Ah lead acid battery

Solar Power
2x Renogy 100 Watt 12 Volt Monocrystalline Solar Panels
Renogy Wanderer Li 30A PWM Charge Controller Edit on 8/3: Victron Energy SmartSolar MPPT 100V 30 amp (changed the system to allow for future growth and a more sophisticated controller)

Power Needs
ARB 50 Quart Classic Series I Fridge
CPAP Machine

Shore Power Charger
Schumacher SC1280 15A Rapid Charger

 

[NatersXJ6]

I don’t know about your Power Wagon specifically, but in my Jeep, you have to push a dashboard button to turn on the inverter every time you shut off / start the vehicle. This gets easy to forget in situations like National Parks where you might stop every 15-20 min or less to see something. It would probably be better to figure out how to hook the battery into your 12v system so it charges without specific input from you. Of course, in western parks, you will want to put your fridge in a bear box at night, and that means power/battery too.

 

[bikelanta]

Fwiw,
You may have problems with your inverter.
Assuming at its 15A output, ’Specs of that Shumacher charger states 3.6A input. Thats over 400W.

Good call. I should mention that it also has a 3A output setting for slow charging too. I would plan to keep it at that level to stay below the threshold.

 

[bikelanta]

I don’t know about your Power Wagon specifically, but in my Jeep, you have to push a dashboard button to turn on the inverter every time you shut off / start the vehicle. This gets easy to forget in situations like National Parks where you might stop every 15-20 min or less to see something. It would probably be better to figure out how to hook the battery into your 12v system so it charges without specific input from you. Of course, in western parks, you will want to put your fridge in a bear box at night, and that means power/battery too.

Yes, I do have that same button. It appears so far that it remembers the last state it was in when shutting off and restarting the truck.

Appreciate the call out on the bear box. I’ve been trying to figure out how it would get handled then.

To your comment about tying into the 12V system, I thought about getting a DC-DC charger, though I don’t want to be hasty in my selection and then need to change it again once I come up with my full electrical system plans. That being said, to your point, it might be worth it.

 

[4000lbsOfGoat]

Do you run your CPAP on AC? Typically they are actually DC devices so going from DC (battery)-->AC (inverter)-->DC (device) is really inefficient. If you can get a direct DC cord for the CPAP then you might get a lot more life out of the battery.

 

[kb1ejh]

Speaking of DC-AC-DC... Why not run the fridge off AC when the invertor is running? Check the AC amps and see if that is possible. The ARB has an auto switch over that will make the AC priority when both AC and DC are powering the fridge. Might allow your G31 to get a better charge without a constant drain on it while you're driving. Mine is plugged in to AC when home for several days in the summer. The solar will recharge the battery and the fridge stays on AC so when I head out the battery is already topped off.

 

[bikelanta]

Do you run your CPAP on AC? Typically they are actually DC devices so going from DC (battery)-->AC (inverter)-->DC (device) is really inefficient. If you can get a direct DC cord for the CPAP then you might get a lot more life out of the battery.

Good call out. I’ll look into it. Thought about it before, but never bothered to buy.

Unrelated question, what’s the backstory on your username? I’ve seen it on here before and wondered.

 

[bikelanta]

Speaking of DC-AC-DC... Why not run the fridge off AC when the invertor is running? Check the AC amps and see if that is possible. The ARB has an auto switch over that will make the AC priority when both AC and DC are powering the fridge. Might allow your G31 to get a better charge without a constant drain on it while you're driving. Mine is plugged in to AC when home for several days in the summer. The solar will recharge the battery and the fridge stays on AC so when I head out the battery is already topped off.

I like this call out. I could connect the AC to the power strip and the DC to the G31. When we drive, the inverter runs it and when we stop the G31 runs it. When we start again, the Schumacher can recharge the G31 (though I imagine the drop isn’t much for these short stops).

 

[bikelanta]

Do you run your CPAP on AC? Typically they are actually DC devices so going from DC (battery)-->AC (inverter)-->DC (device) is really inefficient. If you can get a direct DC cord for the CPAP then you might get a lot more life out of the battery.

Thanks again for the tip on this one. Ordered a DC cord for the CPAP last night.

 

[Herbie]

You may have problems with your inverter.
Assuming at its 15A output, ’Specs of that Shumacher charger states 3.6A input. Thats over 400W.

I don't think this post got enough attention. That 400w inverter is small - almost tiny. It will almost certainly fail to simultaneously run the schumacher and charge the GZ, let alone also power the ARB during that time.

I suggest rigorous testing - and I mean actually partially discharging both the GZ and the group 31 battery and then hooking everything up. No fair just plugging everything in when the batteries are full - that won't simulate the load.

 

[bikelanta]

I don't think this post got enough attention. That 400w inverter is small - almost tiny. It will almost certainly fail to simultaneously run the schumacher and charge the GZ, let alone also power the ARB during that time.

I suggest rigorous testing - and I mean actually partially discharging both the GZ and the group 31 battery and then hooking everything up. No fair just plugging everything in when the batteries are full - that won't simulate the load.

Thanks Herbie. Luckily we do have a shakedown trip coming up, so I’ll be able to do just that. I’ll get the ARB cooled down before the trip by running it off the G31 and letting that drain and then charging during the drive. I’ll run my CPAP off the GZ a night or two to drain it also.

I did purchase a Victron DC to DC charger for connecting into the 12V system after some of the earlier commentary. Our PW has dual alternators rated at 380 amps. Might as well go that route instead of the limited inverter. So I’ll plan to connect that to the G31 and just leave the ARB plugged into it all the time. I’ll continue to charge the GZ via the inverter.

 

[NatersXJ6]

Given that the vehicle charging system is already designed to charge car batteries, why the additional dc-dc charger? This question is maybe not only related to this thread, I’ve often wondered that in general.

 

[67cj5]

Pre-emptive commentary: I will be building a better full-time electrical setup into our Super Pacific once it is ready but for now I'm trying to deal with an assembly of random parts to meet some short term needs.

All components discussed in this thread are linked below the narrative.

I'm thinking through my plan for maintaining power for our family during a week long trip later this year to some national parks. Our primary power needs are a CPAP machine and an ARB fridge. The campgrounds at which we are staying do not have shore power connections. Our Power Wagon has a 400 watt power outlet in the truck bed. While driving, my plan is to plug both the Goal Zero and the Schumacher automotive battery charger (connected to the Group 31) into a power strip that is plugged into the 400W outlet to maintain charge in both batteries. The fridge is then connected into the Group 31 battery using an ARB style plug. When we stop, the battery will power the fridge and while driving, the charger will charge the battery. The Goal Zero gets used exclusively for the CPAP machine at night. I've generally found that I can really only get 2 nights, maybe 3 out of the GZ for the CPAP, so I don't connect the fridge into it. I've also found that the fridge can run 3-4 days (maybe more, but haven't tested) running off the Group 31 battery without a charge.

During this trip, we'll be exploring national parks (Yellowstone/Grand Teton) during the day, so the truck will get driven and thus the bed outlet will prove helpful. I also have solar panels that can be leveraged, if it makes sense to do so. The panels can either be connected directly to the Goal Zero, which has a built in solar controller, or through a simple Renogy Solar Controller and then connected to the Group 31. The panels are not attached to the truck, so would largely only see use at the campground, assuming there is any decent sun.

My questions:

1. Any reason that I shouldn't use the power strip in the bed outlet, assuming we stay below 400W?
2. Any reason that I shouldn't use the Schumacher 15A automative charger to charge the Group 31 battery while on the move? (Edit: it has a 3A output setting in addition to the 15A rapid charge.)
3. Does the 400W outlet seem sufficient that we wouldn't necessarily need the solar panels?
   1. Drive time to Teton is 8 hours (probably 10 with stops)
   2. Drive time from Teton to Yellowstone campground with stop is about 3 hours, maybe more with stops
   3. Projecting 1-2 hours of driving each day while at parks, just to be out exploring
4. What am I missing?

Batteries
Goal Zero Yeti 400 with 35Ah replacement Duracell battery (originally 33Ah)
Duracell Group 31 Deep Cycle 105Ah lead acid battery

Solar Power
2x Renogy 100 Watt 12 Volt Monocrystalline Solar Panels
Renogy Wanderer Li 30A PWM Charge Controller Edit on 8/3: Victron Energy SmartSolar MPPT 100V 30 amp (changed the system to allow for future growth and a more sophisticated controller)

Power Needs
ARB 50 Quart Classic Series I Fridge
CPAP Machine

Shore Power Charger
Schumacher SC1280 15A Rapid Charger

Two Fully Charged Group 31 115Ah batteries will power the ARB 47L/50Qt for 6.5 days or 6 and a half days when set to 2*c in an Ambient temp of 23 to 25*c taking them down to 50% SOC so using one you will get around 3 and a bit days out of it because you only have 57.5Ah of useable power before you take the battery down too far, Some Deep Cycle batteries can go down to 30% SOC giving you 80.5Ah to play with using 70% of their power.

At 2*c in ambient temps of 23 to 25*c your ARB will use between 17,5 to 18Ah per 24 hours,

Hope that helps.

 

[bikelanta]

Another common scenario, the house battery needs to be located excessive distance from the charging source. DC to DC can boost charging voltage to compensate for losses due to conductor length.

This is my current reason for it. The one area of my engine bay where I would consider placing a second battery will soon be occupied by an ARB twin air compressor. So, the batteries are in the bed of the truck, near the fridge. Also, while they are currently lead acid, I anticipate switching them to lithium in the future for the weight savings. Different chemistry batteries demand different charge profiles, so I anticipate the DC to DC helping on that front.

 

[jadmt]

Just got back from 4 days of camping where i never started my truck a single time. My jackery 1000 ran my arb 50 the entire time. It was hot like 100f hot and my fridge was inside the hot truck Which was even hotter. It was down to 11% when we left and a ~3 hour drive put it back to about 50%.