Let's talk portable power. Amps on demand. On foot.

[XERTYX]

So I've wanted for years to have a backpack with a detachable solar panel/panels. Sort of an emergency and or SHTF (I hope that isnt political) scenario bug out bag so to speak.

Youd need many of the same things as if you cut the cord and lived a mobile nomadic life. More efficient fuel etc etc. 

How do you power your sawzall off grid?! (Homefield advantage I've done this with a B&D cordless 7.2V reciprocating saw)

Dependant upon circumstance, How many watts solar panel would you advise to be mounted on a backpack? Or is there a better option like a fanny pack? Or a case with a handle?

Where do you store the power? (Pun intended but unnecessary) 

If you were hiking cross country what would you use to store electricity?  What types of controllers? Battery chemistries? Amorphous panels? Poly? Mono? Why?

Discuss. If it makes you happy.

*SHTF= Stuff Hits The Fan

 

[XERTYX]

My ideal situation as best I can imagine it is a 10w or thereabouts (I know the size of the 5W panels I started with) poly panel with an MC4 compatible extension cord. (Coiled under the panel until needed) and a controller (not sure of the type PWM or MPPT) a 12Vlithium ion battery pack as used for CCTV camera back up power. And a 12VDC->5VDC adapter. 

I've seen loads of backpacks with amorphous panels on them but they seem fragile to me. And low output.

 

[maki2]

Save the solar for your electronics such as a communication device with GPS and an emergency beacon. Or you can even get handcrank re-chargers for cloudy weather days. If you are talking about a real SHTF as a major event you won't be having much in the way of anything out there to connect to. So you need to have the maps already stored on the devices. Remember also that signals can get blocked by trees and terrain.

Just get one of the lengths of chain saw that has a handle on each end, they are in sporting goods stores and online too. That will roll up compactly into a very small pouch and it weighs very little compared to taking along a battery back. It will quickly cut through wood. You can also purchase handles that will hold saws-all blades if you absolutely feel you must have that type of blade with you. Most of the major tools companies that sell powered sawsalls have those handles for sale at hardware stores.

It would take a very long time for a small solar panel to recharge an 18V power tool battery but with a hand saw you don't have to wait for a full day of sun to do a few minutes worth of muscle powered sawing time. I am sorry but your concept of what to carry with you has me scratching my head in wonderment abut being addicted to battery powered tools for very simple and quick tasks. Don't get me wrong, I love power tools but I do know that I can do such things by hand pretty quickly.

For instance yesterday my bandsaw blade broke when I was cutting notches in some aluminum angle. I got out my hand, clamp frame, jewelers saw and made the cuts in two minutes time.

I like knowing that I am versatile and can use electronics and power tools as well as being nicely skilled with hand tools. You want to be prepared for SHTF then you might want to start thinking about developing more skills with bushcrafts.

 

[travelaround]

I'm about to order a Luci Mpowered Pro which is a solar light, but also has a USB for charging your cell phone. Their video on Amazon shows someone with the Luci attached to his backpack.

https://www.amazon.com/gp/product/B0794WJ2ST/

 

[Trebor English]

Since this is being carried the weight might really matter. In that case double batteries might be a bad idea. Use the solar to charge the sawzall 7.2 volt battery directly and use that battery to run the saw. On days that you don't cut stuff you could charge the cell phone battery and the sawzall battery. During days when it rains or you walk all day you could use the 7.2 volt battery to charge the cell phone.

A separate battery only used to charge other batteries and not otherwise used would be bulk and weight that would be easy to shed.

There are boost (increase) and buck (decrease) power supply regulators. That is the basic idea of MPPT charge controller. Whatever watts you have from whatever source can be applied to whatever load you have. These are reasonable in price and efficiency as long as all the ins and outs are in the 5 to 20 volt arena.

You can probably set up a reflective concentrator to boost the watts from a small panel using a light weight aluminized mylar blanket.

 

[lenny flank]

Back in my younger days of hiking and backpacking, I did have a portable electric system, solely to charge my phone. I had a 45w foldable solar panel that hung on the back of my pack, which ran inside to a Tekkeon portable battery, into which my phone then plugged to charge.

It all weighed maybe 5-6 pounds.

This was 10-12 years ago, so there are probably newer versions available to do the same thing, with bigger panels and batteries.

 

[highdesertranger]

back in my younger backpacking days we didn't have any stinking electronics. we had never even heard of a cell phone. the was no such thing as digital maps. funny how that worked, never got lost either. highdesertranger

 

[B and C]

Magnetic compass and a paper map were the tools. Analog everything. Now it's digital everywhere you turn and don't get me started on the fools that drive and are on the phone. I think they call it phone anxiety where you are afraid to not have the phone.

Now, what was the topic again? Oh yeah, power for charging stuff while backpacking.

 

[Spaceman Spiff]

So I've wanted for years to have a backpack with a detachable solar panel/panels. Sort of an emergency and or SHTF (I hope that isnt political) scenario bug out bag so to speak.
There are a number of packable solar panels available ranging from 2W to 40W and more:  https://www.outdoorgearlab.com/topics/camping-and-hiking/best-solar-charger
Can be used for any electronics that charges from USB.

How do you power your sawzall off grid?! (Homefield advantage I've done this with a B&D cordless 7.2V reciprocating saw)
I carry a small, packable hand saw (when needed); no batteries required.  For as little as it is used why pack a sawzall?

Dependant upon circumstance, How many watts solar panel would you advise to be mounted on a backpack? Or is there a better option like a fanny pack? Or a case with a handle?
Always start with need and work backwards.  How much charging are you going to need?  How much margin?

Where do you store the power? (Pun intended but unnecessary) 
In the device batteries, to minimize pack weight.

If you were hiking cross country what would you use to store electricity?  What types of controllers? Battery chemistries? Amorphous panels? Poly? Mono? Why?
Device batteries, no controller, chemistry as delivered with device, packable panels I've seen are poly.

In a SHTF scenario how much electronics will actually be useful?

 

[RVTravel]

Voltaic systems dot com may have what you want

 

[XERTYX]

Sorry, I've been away for a bit. Real life stuff. 

So I dont actually need to power an off grid sawzall, but I have needed to and have done it successfully when I lived on a boat. I removed the nicad battery pack, disassembled and inspected the motor, and lubricated it and ran it directly on a 12v battery bank.

I'm thinking a 10 watt poly panel mounted on the exterior of the pack with an extension cord to place it in the sun during peak hours while I lounge in the shade, 2 18AH 12v lithium ion CCTV back up battery packs, a cheap MPPT or PWM controller, and a 12v to USB adapter. 

When I lived aboard I had 20 watts of solar and 28AH of AGM batteries reclaimed from old UPS power supplies. It served my minimal needs at the time.

I would only absolutely HAVE TO HAVE charging for a smart phone, a USB recharged flashlight, maybe a bluetooth headset, and MAYBE a standalone GPS unit.

I dont foresee that being an issue if I ration accordingly.  The batteries I found are about $25 each, I still havent decided on a panel although I'm leaning towards a flexible panel, and I havent decided on a pack or a controller. 

The batteries have a Male and female "barrel" plug. Like an old school scanner, Nintendo, etc. Both are useable which leads me to believe the charging Circuitry is entirely in the AC wall adapter. 

The plan would be to cut off a Male on one and female on the other battery and wire them in parallel and attach the controller to that. This would leave a Male and female connection on each battery. The female would be routed to the outside of the pack to allow wall charging to keep it 100% all the time and the Male would be unused. It could also be kept in the vehicle plugged into 12v to stay topped up until needed.

Anything I'm missing here?

 

[1shemp]

Why would you need saws and drills and such just to go backpacking?

 

[Spaceman Spiff]

I'm really confused about what you are trying to accomplish.  In one paragraph you talk about wanting to run a sawzall on 12V, the next you are talking about SHTF scenarios, and another talking about backpacking.  All three have conflicting requirements IMHO.

Sawzall - would run mine on an inverter or buy an battery operated version plus charger.  Neither come close to my list for boondocking gear let alone in a backpack.

SHTF scenarios - more ammo, less electronics.  What electronics I carry will be easily charged from a small, light backpacking solar setup.

Backpacking - no cell signal where I go; phone stays back at the truck.  GPS and inReach only rechargeable electronics along, again easily recharged directly (if needed) from a small solar panel.

Backpacking solar panels have their own controller integrated and output USB voltage, no need to convert from 12V.  10W is approximately USB2 power.  Long power cords without large voltage drop are HEAVY.

Average American can only carry about 2 weeks worth of food and 2 days worth of water.  I've used my GPS and inReach for over three weeks with intermittent use; no need to charge or carry additional batteries.  Use my LED headlamp for a year before changing batteries.

 

[tx2sturgis]

You are probably going to want a small portable panel, but you will also probably be building a small fire every evening or morning.

A couple of years ago, up in a remote area of Wyoming where a bunch of us were camping, a group of young people had a Biolite stove that makes electricity...they were powering LED lights and charging phones. I saw it in action.

You might want to add something like this to the backpack:

https://www.bioliteenergy.com/products/campstove-2

Having said that, like the other old fogeys here, I remember orienteering with a magnetic compass and paper maps for guidance and a flare gun for when things went bad!

 

[MrNoodly]

How do you power your sawzall off grid?!

How about becoming less dependent on power tools? Hand-powered tools are way lighter and more compact.

 

[XERTYX]

That video is awesome. I didnt realize how long it was until I was already invested though. Haha. It's pretty well idiot proof. But I didnt get to finish it because I lost internet service. It's such an awesome design that I think I will make one. I especially like that its water proof but I do dislike that the lid has to be opened to use it. I'd make a change or 3 but I like it. Thanks for that.

The biolite stoves have piqued my interest for some time now. And they seem to have came down in price considerably. I may get one of those as well.

And I like power tools for some applications. I wouldnt lug one around in a backpack though. I have ran a sawzall off of solar before on a boat for hurricane repairs though.