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Inspired by Darren's hakvan, I'm building a tek teardrop camper trailer


tekpunk
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Hey guys, I'm currently working o building a teadrop camper trailer. Me and my gf are going to live out of it for a while and travel. I want to be able to find free wireless access points wherever we park, so we have free wifi for our laptops, phones. I was thinking of putting an antenna on the roof of the teardrop, and hooking it to a router that has external anetennas. Basically, using it as a wireless bridge. It would connect to the free hotspot with the big external antenna, and then give us wifi with the other antenna. I need your help with what equipment to use, and I welcome any criticism of my idea and anyone else's better ideas lol.

I also plan on running most of this equipment of a solar/12vbattery setup, which I only mention in case it becomes relevant.

I'd love help, links from people with experience doing this kind of stuff. I'll post pics and document everything I do/use.

Thanks in advance

(attached pic isn't mine, it's from https://sites.google.com/site/buildingateardroptrailer/ I'm just using it to show what a teadrop looks like and who I'm basing by build it off of. )

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It sounds like the device is going to be mounted on the outside of the camper.

1. Do you need it to be directional (I think you do)? If so, you need some sort of platform which you can rotate so you can aim the antenna without having to go outside.

2. Are you going to affix it to the outside or are you going to place it on the roof once you arrive somewhere, so only wifi once stationary, nothing on the go? Or will you find a spot to mount it on the inside? Looks like that would be quite a feat...

3. What do you have for power? Only the car battery, or are there alternatives?

I'm fairly certain your best bet is going to be a small, cheap ARM board (Raspberry Pi 2, PcDuino3 Nano, Orange Pi 2, Odroid-C1) and 2 USB wifi adapters of which 1 has its antenna attached via an (RP-)SMA connector. You need a pretty much all-weather box to mount everything into (may involve some power regulator to take car battery power down to a more acceptable voltage), which would only expose the SMA connector and a power plug. Try to get one in a color that people hate to prevent theft, and that doesn't melt when exposed to the sun for a full day. Do some research on what antenna you want to use, or simply build one. There's TONS of tutorials on that out there.

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Ideally, we'll be stopping in places that have outlets so we'll be plugging everything in. But I'm sure we'll have to stop in places where we'll have to run off of the battery.

Wouldn't an ARM board be overkill tho?

I was planning on mounting the antenna outside, and keeping the device inside. I saw some omnis that got really good range too...

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If you're going solar, make sure you choose something like a sealed AGM type battery if mounted inside with you near the charge controller for the solar panels. Close quarters with regular car batteries(and most lead acid batteries) can cause fires and explosions from the gases leaking out of the battery when sparked by electrical appliances, such as the power outlets you plan to hook up to the solar panels, laptops, etc. Can't remember if Darren covered that in the show when he did the van but just a heads up, read up on things before you purchase anything to start your build. Plenty of videos on YouTUBE to help with the whole process for going solar.

I'm currently building a small setup for someone myself and managed to buy all of the parts I needed for under $200 sans the mounting setup I'm going to need to build to house everything and keep off the ground. It's a small 2amp solar panel with an AGM deep cycle motorcycle battery hooked up to an 8amp charge controller which runs to the battery off the solar panel. Hooked to the battery is a small 400(800watt maximum) set of two 125v outlets and one USB charging port which should stay charged during the day and give the person I'm building it for, some light at night and radio along with a small griddle to cook off of and charge his heated vest batteries. It's a project I started and have everything together except the pole to mount the panel on above the persons shack in the woods but in researching how to build this I'm glad I didn't just start buying things like a car battery to run everything off of. Car abtteries also aren't the best for constant re-charging, and won't last if constantly drained and recharged the same way a deep cycle battery will, not to mention the fire and acid hazard if they leak fumes or fluids.

My next project now that I have a better understanding of the setup for solar and indoor batteries, is building a small battery bank to run my a/c off of in the house so I don't need to use the house electric this season. Ideally I'd like to get the whole bedroom off the grid for a couple hundred dollars. Should make for an interesting time trying to figure out how I'm going to fit everything in our tiny bedroom and run the wires outside to a small solar array.

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Wouldn't an ARM board be overkill tho?

Oh? What alternative would you consider more appropriate? Pretty much any router you can buy has an ARM in it aswell. In that case, might aswell get one you can fiddle a bit with.

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@digip That's good info! I was hoping to reuse a bunch of small lead acid batteries people had thrown out, but still worked... The kind that are inside alarm systems. I'll look into that. I was thinking 2 solar panels(cause that's all I can fit and the more the better right?). I was thinking of storing the batteries outside of the teadrop, on the trailer chassis in like a utility box so that it doesn't get wet.

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@digip That's good info! I was hoping to reuse a bunch of small lead acid batteries people had thrown out, but still worked... The kind that are inside alarm systems. I'll look into that. I was thinking 2 solar panels(cause that's all I can fit and the more the better right?). I was thinking of storing the batteries outside of the teadrop, on the trailer chassis in like a utility box so that it doesn't get wet.

Yeah, that should work, just look to see if they are deep cycle batteries and you should be fine with them outside if not sealed like AGM ones, which can be laid in any direction and don't give off any fumes. Some out door batteries have to be equalized every so often though, but not sure on the alarm batteries. I assume they are self sustained/sealed to some extent since they probably are not messed with once installed other than when swapping them out. Just google the brand of batteries you come across before picking them from the trash. You can probably find some decent used ones on craigslist or ebay too.

Here is some info on batteries and what you'll be up against with non-sealed batteries:

http://rimstar.org/renewnrg/off_grid_solar_battery_maintenance.htm#EQUALIZING

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Yeah, that should work, just look to see if they are deep cycle batteries and you should be fine with them outside if not sealed like AGM ones, which can be laid in any direction and don't give off any fumes. Some out door batteries have to be equalized every so often though, but not sure on the alarm batteries. I assume they are self sustained/sealed to some extent since they probably are not messed with once installed other than when swapping them out. Just google the brand of batteries you come across before picking them from the trash. You can probably find some decent used ones on craigslist or ebay too.

Here is some info on batteries and what you'll be up against with non-sealed batteries:

http://rimstar.org/renewnrg/off_grid_solar_battery_maintenance.htm#EQUALIZING

Alarm batteries are just like UPS batteries. They are sealed lead acid. As most of us know, they will vent when they fail. I have a roughly 4000 square foot house, not counting the basement. The battery packs in my rackmounted UPS in the basement failed and burst. We had to open up windows, when it was in the low teens to single digits outside, just to get the sulphur smell out of the house. I wouldn't want that to happen in a small camper. Keep the batteries outside.

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Alarm batteries are just like UPS batteries. They are sealed lead acid. As most of us know, they will vent when they fail. I have a roughly 4000 square foot house, not counting the basement. The battery packs in my rackmounted UPS in the basement failed and burst. We had to open up windows, when it was in the low teens to single digits outside, just to get the sulphur smell out of the house. I wouldn't want that to happen in a small camper. Keep the batteries outside.

We had large deep cycle batteries at our data center that ran all of the mainframe and terminal equipment, printers and workstations. Probably about 5 across and 6 racks high at 4 racks wide along the back wall, so that was probably 120 batteries if I remember correctly. They only kicked in for a few seconds and would at most last about 30-60 minutes for which shortly after electric cut out, batteries were only used till the diesel generator kicked in which would be almost immediately unless it needed fuel or had its own failure(which did happen a few times). The generator helped maintain charging of the batteries and constant voltage requirements via the batteries, power conditioning as most battery backups do, they ran off the generator to keep things going till the power came back on. We did have a battery go once(12 years there and I only recall one incident). The way we knew, was the foul smell as you mentioned. I never did see anyone replace it although they did at one point replace the whole rack. The smell went away after a few hours and our sub floor ventilation sucked most of the smell out. Pretty rank when it first happened but nothing you couldn't sit through and we were only a few feet away from the battery banks behind our workstations. There was enough redundant power in the banks though we didn't seem to have any issues other than the smell which for us was dissipated by the air system. In a house I imagine this was like getting hit with a stink bomb and not as pleasant..

Any battery failure regardless of the battery type, if you have one leaking or explode, you don't want it in your sleeping compartment or near anything perishable, flammable, due to the fumes possibly igniting under spark. He did mentioned he was building the battery pack outside the camper so he should be fine though. https://forums.hak5.org/index.php?/topic/34940-inspired-by-darrens-hakvan-im-building-a-tek-teardrop-camper-trailer/#entry259414

Recycled UPS batteries if you have them on hand work well to re-purpose them and should still work for a solar bank even if they were from an old UPS although they only last about 30 minutes for a single (500-1000w desktop)computer/battery since they don't have high Ah's. Laptops maybe a few hours or more(not including the laptop battery time). Motorcycle batteries don't last that long either but they do make larger Ah AGM batteries for things like wheel chairs and outboard motors where water is an issue and long charge is needed, they just cost a lot more. A few smaller batteries chained in parallel should double their capacity though, while not increasing voltage. 12v batteries would be fine for this setup with the right solar setup, charge controller and power inverter. I wouldn't put anything inside a small space other than maybe a few small AGM type batteries under the back hatch to keep out of the rain, and even then only because they are a bit smaller for storing in compartment, sealed, and easily maintained and swapped out. Any auto incident while moving would likely not be good regardless of where the batteries are and probably the last thing you'll be worried about if you get hit or vice versa. The nice thing about them is they shouldn't give off any hydrogen since they don't need to breathe like other battery types and can be laid in any position to stack on their sides, taking up less space vertically on top of one another in a side wall.

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I had a small APC UPS. Nice device that worked wonders when some genius digging up the street nicked the power cable. After about 7 years of trusty service I got a call from my girlfriend that she heard a bit of a bang, there was a truly foul smell of burnt plastic in the house and the network server was gone. The device was cracked and the battery, while still sealed, has expanded quite a bit. Whatever happened, it was contained (no thing else in the house suffered from it - just the devices attached to the UPS didn't get any more power), but the device itself was shot to shit.

Bottom line: Batteries work great but they can and do fail, and since they make a bit of a mess when they do it's best to keep them outdoors whenever possible. Get some idea of the power you need for how long, and if your recharge capabilities are able to sustain this usage for the timeframe you envisaged.

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Yeah, I've actually got 3 APC UPS backups. Two small and one large, and one of the three did go, but nothing catastrophic. Battery just stopped working and unit was still good. Ordered replacement battery and was all good to go, unit still worked. Guess I dodged the bullet on that one.

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