Remote Camp Trailer System

[Dontatsu]

I am considering building a system to power a small remote base camp for hunting or camping. My thought is to mount an overhear rack system above a 5'6" wide by 7 foot long utility trailer I have.I would then like to build the batteries and control systems into a 45" x 20" x18" double wall cargo box I have. My current idea is to use LiFePO₄ cells configured to make up a 48V system into an all in one box. This box would be on wheels and could be places wherever required and have quick detach wiring to the panels that would remain permanently on the trailer. I'm learning all I can about Solar in general but Im curious if anyone has any thoughts relevant to this type of mobile trailer based remote system.

Thanks
D

 

[timselectric]

Cold weather is the only issue that I can think of. But since it's on wheels. You can move it out of the Cold when needed.

 

[Ekard]

I kinda/sorta do this already, though on a smaller scale, and it is darn handy to be able to wheel some juice out into the woods when I need it.
My panels however, are not permanently mounted to a trailer, rather they go on my truck's ladder rack then I need to use them.
The only criticism of your idea I can offer is that your panels on a utility trailer sound like an easy target for thieves.

 

[Dontatsu]

I kinda/sorta do this already, though on a smaller scale, and it is darn handy to be able to wheel some juice out into the woods when I need it.
My panels however, are not permanently mounted to a trailer, rather they go on my truck's ladder rack then I need to use them.
The only criticism of your idea I can offer is that your panels on a utility trailer sound like an easy target for thieves.

Thanks. The trailer will be primarily used in quite remote areas. When home they will be parked in a very secure location so Im not that worried about the panels.

 

[Dontatsu]

Cold weather is the only issue that I can think of. But since it's on wheels. You can move it out of the Cold when needed.

I was actually more worried about heat since I will mostly use it in hot dry desert conditions. As to cold I suppose I should monitor it as well as heat. Are there BMS systems or temperature monitoring devices that would work for this?

 

[timselectric]

I was actually more worried about heat since I will mostly use it in hot dry desert conditions. As to cold I suppose I should monitor it as well as heat. Are there BMS systems or temperature monitoring devices that would work for this?

Most BMS's include temperature sensors.
You mainly don't want to charge below freezing. (I wouldn't even charge close to it)

 

[timselectric]

You also don't want the AIO to get too hot. Maybe remove the lid of the cargo box while in use. Or add ventilation.

 

[MisterSandals]

I am considering building a system to power a small remote base camp

Do you have an idea how much power you intend to use each day?
You should do an energy audit to determine your daily watt hours you expect/need from this system.
How much power will you need to store in batteries (for nighttime power and power to get you thru cloudy days)?

 

[Dontatsu]

Do you have an idea how much power you intend to use each day?
You should do an energy audit to determine your daily watt hours you expect/need from this system.
How much power will you need to store in batteries (for nighttime power and power to get you thru cloudy days)?

I am in the process of figuring that out. The rack system I would build would allow 4 x 200 Watt panels. The box mount would hold at least a 100ah 48V battery pack. This will likely be used primarily in the desert in a high sun regime. I will also have a generator to supplement charging if needed.

 

[Ekard]

4.8KW/hr for a portable system? With good solar exposure? Wondering what you're doing out there in the desert that would need even that much. Off-grid welding shop? LOL My kids' 1600 sq/ft townhouse uses like 10-15KW/hr/day (including the heat pump).

 

[Dontatsu]

4.8KW/hr for a portable system? With good solar exposure? Wondering what you're doing out there in the desert that would need even that much. Off-grid welding shop? LOL My kids' 1600 sq/ft townhouse uses like 10-15KW/hr/day (including the heat pump).

Well I live in the Bay Area and we have had numerous week long power outages at the house due to fires. I lost all my game in the deep freeze twice. Also I spend time in a fairly elaborate multi person hunting camp. Plus maybe Burning Man lol.

 

[Ekard]

Well I live in the Bay Area and we have had numerous week long power outages at the house due to fires. I lost all my game in the deep freeze twice. Also I spend time in a fairly elaborate multi person hunting camp. Plus maybe Burning Man lol.

OK, so there's a lot to your situation.
- San Francisco, totally flat mounted panels, 4.9 peak sun hours, 4x200watt panels, 3.92KW/hr per day (but let's call it 4.5 since you do make juice during non-peak hours too). You can't fill your 4.8KW/hr battery bank from total depletion in one day with that level of production, but that may not be a requirement to you. You might consider adding two more panels, if there is space on your trailer, if you want to be able to fully charge the battery bank AND be able to use it heavily.
- Your panels are going to provide some shade for your box of batteries and electronics, but it still needs to be ventilated. Oddly enough, my enclosed cargo trailer (painted black) doesn't become an oven even in 90 degree weather. I think you'll be fine here, but no one will fault you for adding temperature sensors to your equipment.
- You have a non-mobile job for this system as a freezer backup. Using a number for a modern, 20cu/ft chest type freezer, let's say 350 watts (which is when it's running, and how much time per day it runs depends upon how much you open it, where you have it stored, etc.). Let's say it may run 50% of the time worst case, so you're at 4.2KW/hr per day. If you're starting with 4.8, making 4.5 and using 4.2 per day, sure, your freezer can weather a week long outage with room to spare (maybe even enough for your fridge and a little well regulated lighting). Hopefully, you're not out hunting when power goes out. Might be wise to select an AIO with a generator or grid input if outages get prolonged.
- I can only guess at your hunting camp, but a hunt club I belonged to had a couple freezers, couple fridges, microwaves, a big screen TV, and lighting. Also a well pump. We had on-grid power, so I never really looked at our consumption. But since we only cooked breakfast and dinner for a maximum of 25 hunters, and maybe watched two hours of TV after a day's hunting, I'd guess your system might be able to support that.
- Burning Man? No idea what y'all do there, but guessing a lot of fans for cooling and lighting.

 

[Dontatsu]

OK, so there's a lot to your situation.
- San Francisco, totally flat mounted panels, 4.9 peak sun hours, 4x200watt panels, 3.92KW/hr per day (but let's call it 4.5 since you do make juice during non-peak hours too). You can't fill your 4.8KW/hr battery bank from total depletion in one day with that level of production, but that may not be a requirement to you. You might consider adding two more panels, if there is space on your trailer, if you want to be able to fully charge the battery bank AND be able to use it heavily.
- Your panels are going to provide some shade for your box of batteries and electronics, but it still needs to be ventilated. Oddly enough, my enclosed cargo trailer (painted black) doesn't become an oven even in 90 degree weather. I think you'll be fine here, but no one will fault you for adding temperature sensors to your equipment.
- You have a non-mobile job for this system as a freezer backup. Using a number for a modern, 20cu/ft chest type freezer, let's say 350 watts (which is when it's running, and how much time per day it runs depends upon how much you open it, where you have it stored, etc.). Let's say it may run 50% of the time worst case, so you're at 4.2KW/hr per day. If you're starting with 4.8, making 4.5 and using 4.2 per day, sure, your freezer can weather a week long outage with room to spare (maybe even enough for your fridge and a little well regulated lighting). Hopefully, you're not out hunting when power goes out. Might be wise to select an AIO with a generator or grid input if outages get prolonged.
- I can only guess at your hunting camp, but a hunt club I belonged to had a couple freezers, couple fridges, microwaves, a big screen TV, and lighting. Also a well pump. We had on-grid power, so I never really looked at our consumption. But since we only cooked breakfast and dinner for a maximum of 25 hunters, and maybe watched two hours of TV after a day's hunting, I'd guess your system might be able to support that.
- Burning Man? No idea what y'all do there, but guessing a lot of fans for cooling and lighting.

Thanks. That's fantastic input. I also have a pair of little Honda eu2000i generators that I converted to run on propane and I can use those to top up. If the power is out I won't open the deep freeze at all. This is an open deck utility trailer so four panels is what the footprint of the trailer will allow without a ton of overhang. I will likely arrange it so that it is hinged to allow it to be propped up and tilted for more optimal sun exposure.

For me this is just a fun project more than a strictly practical venture. If i was being strictly practical I guess I would buy a server battery rather than building a DIY battery but its just interesting.

 

[MisterSandals]

4 x 200 Watt panels. The box mount would hold at least a 100ah 48V battery pack

Messing with numbers...

51.2V nominal battery x 100Ah = 5120Wh

5120Wh / 800W solar = 6.4h to charge from empty at 100% efficiency
800W / 56V charge voltage = 14.2A charger

 

[Ekard]

Thanks. That's fantastic input. I also have a pair of little Honda eu2000i generators that I converted to run on propane and I can use those to top up. If the power is out I won't open the deep freeze at all. This is an open deck utility trailer so four panels is what the footprint of the trailer will allow without a ton of overhang. I will likely arrange it so that it is hinged to allow it to be propped up and tilted for more optimal sun exposure.

For me this is just a fun project more than a strictly practical venture. If i was being strictly practical I guess I would buy a server battery rather than building a DIY battery but its just interesting.

Looking forward to seeing what you end up with.
BTW, there was a fellow from Ukraine made a post here, saying how his little solar hobby his wife would complain about is now providing them lights in the house during blackout periods. You never know, and are better off for your venture.

 

[BoloMKXXVIII]

I built a 6.7 kwh system as a learning project when I took a year off for health reasons. My wife put up with my project but really saw no benefit to it...at the time. A year later and three major power outages (two being tropicalstorms) later and her opinion has changed. We do have a gas generator too, but other than the yearly service, it hasn't been used.