Backpack portable power. Advice needed.

SteveK
SteveK Solar Expert Posts: 387 ✭✭
in Off Grid Solar & Battery Systems #1
So, the time for backpacking by choice is here in the Northeast. It is a good time to get away from all the hustle and bustle. Get back to nature and forget about technology for awhile. But like everyone else there are some conveniences we like to take along with us for extended 7-10 day excursions to places that are primitive.

Things like flashlights, headlamps, camp lights, portable HF tranceivers, APRS tranceivers, GPS receivers, curling irons (kidding on this one). There could be many others depending on one's health or circumstance. This brings solar power charging into the loop I feel. There seems to be some great options out there as of late.

At first I bought this one with some dividend dollars and 20% discount at REI. http://www.rei.com/product/827121/goal-zero-guide-10-plus-adventure-kit-solar-charger

Attachment not found.

This one seems to work pretty well but it is a costly solution. The two best things about this setup in my opinion is that it has a built-in boost converter to allow 12V @ .2A output. And second it has a raw unregulated output to feed to charger shown in picture. This unregulated output is something special to this kind of solar setup so I've seen. This allows connecting several panel sets in paralell to increase the total size of the system. They sell a cable to do so.. here: http://www.goalzero.com/shop/p/45/Solar%208mm%20Splitter%20Cable/

Attachment not found.

After some more digging on the web I found this: http://www.amazon.com/Instapark%C2%AE-Portable-Charger-Compatible-Devices/dp/B006ZRYU9O/ref=pd_sbs_auto_6

Attachment not found.

This is obviously a larger array at 10.5W versus the other at 7 but it has a glitch. It only has 2-5V USB outputs altough they can source 1A (stated) ea.

Now, I do know that I could boost this to ~12V while losing a load of power but I was thinking I'd try something different. I would like to make provision on both these arrays to be able to series connect them. Problem is, I'm not sure of the series current handling capability of these cells.

The reason I want to do this may be obvious to some but here it goes. I need to produce a higher voltage to recharge my Yeasu VX-8DR @ 7.8V min and my Yeasu FT-817ND @ ~12V radio equipment. I'm not really looking for a 3 stage routine as such, just enough to keep me going is all. And the boosted 12V .2A output on the goal zero will simply take too long to work well enough. What a waste of energy to paralell these boost converters.....

I know there are bigger portable solutions out there but I like two seperate one's. This because I can pack light when I choose by taking only one. So the sloution needs to be backward compatible to what they are today.

Thanks in advancve for any input!
· Share on Twitter

Comments

  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #2
    Re: Backpack portable power. Advice needed.

    Well I was able to remove the plastic breakout box easily from the Goal Zero panel. I believe the Amazon one is mounted identically. I will remove this when it arrives. I'll try the series connection and cross my fingers.

    I just wish somone had some idea about the Isc max of these cells. It will be a shame if I fry them. But then again it would be a less costly education than many things I've screwed-up.....
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Backpack portable power. Advice needed.

    there's only 1 way to find the isc and that's to aim directly to the sun around solar noon and short the output through a good meter that can measure that current with some degree of reliability and accuracy.
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #4
    Re: Backpack portable power. Advice needed.

    Thanks Niel,

    I am wondering if I should be concerned with this series string at all? I'm used to seeing the "maximum number of panels allowed in a string" spec for the larger panels. This to me indicates either an overvoltage or overcurrent situation if too many are connected.

    I can't find out who makes these cells and just don't know if I should be concerned at all to begin with. They appear to be semi flexible. Guess I'm gonna have to try it and possibly fry it..... That's how power hungry these radios are especially the FT-817. I know they could've done much better in the RX power consumption department. It's just so small and such a diverse rig that it is ideal for trekking with to the hills.

    Steve
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: Backpack portable power. Advice needed.

    stevek,
    i'm not real familiar with the 817, but it is an oversized multiband ht with ssb capability.;) i am aware in general of it having a 9.6v battery pack or 8 aa batteries. would the radio allow for simultaneously feeding of solar to the batteries while it's in use? most aa nimh batteries can be fast charged if with a proper charger (individual batteries, but unsure for series strings of 8. 8) maybe rc chargers accommodate? this often enlists an amp or so of charge current plus the required current of the radio itself. shut the radio off and you have even more current to the batteries. how does yaesu recommend it be done?
    · Share on Twitter
  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
    #6
    Re: Backpack portable power. Advice needed.

    The 817 has a built-in charger for the rechargeable pack. It is a manually-operated function, and is a relatively slow (160-200mA) charger. Can't adjust the charge rate, so putting high-capacity rechargeables in the radio simply means even longer charge time. The vast majority of the power being drawn is going to be by the radio itself if simultaneously in operation.

    If the charger function isn't enabled, the battery pack is always trickle-charged (~12mA) when power is supplied at the DC jack. Diodes allow the radio to draw power from whichever power source is stronger, so as long as there is good sun and plenty of power from the panels, it will run off that - as well as charge the battery pack. If panel power drops below requirements, it will draw from the battery pack seamlessly.

    There are some 817 users who go hilltopping that have flexible / foldable solar panels with a voltage regulator on their output so they can be directly connected to the radio without an external battery. More simply add a small AGM battery - panels charge AGM, radio draws off it.

    The 817 only needs 9V or so for the radio, running the input voltage up higher than that simply wastes the extra power as heat by the voltage regulator in the radio. I believe you do need to get up to 13V or so for the battery charger to operate properly. (It will still function, but can't get a high enough terminal voltage to properly charge the batteries.)

    Only caveat, if the battery voltage is below a certain point (can't remember right off, think it's 12-12.5V) the radio defaults to 2.5W max assuming it's on battery power. It is possible to override that to the 5W setting, but something to be aware of.
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #7
    Re: Backpack portable power. Advice needed.

    Niel, the 817 comes with a NiCad battery pack that is pretty weak at ~1 aH. The radio will charge this but very slowly at 10 hours with radio off. Yeasu also sell an alkaline adaptor that I use. It has a "sense" wire that needs to be defeated to allow you to place NiMh cells in it and charge them. Great news as you just doubled your capacity to ~2.2aH. Only now it takes 20 hours to charge it....:cry:

    So what I do is keep two set of NiMh batteries and charge one set external from the radio while the other is installed in it. The problem is getting these panels rigged without breaking them, while still keeping the functionality of the USB charging circuits. I've looked a bit more online and think I see that series connecting these panels should not be a problem. There are some panels out there made of the same printed-on Monocrystalline cells that are producing 25V. At least they look identical. We shall see. I wanted to stay away from Amorphous and CIGS.

    The RC car charger is something I'll look into! Not a rapid one though. The charger that coes with the Goal Zero works well but is only a 4 cell and I need 8

    Thanks!
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #8
    Re: Backpack portable power. Advice needed.

    Hey Joe, You nailed it right on the head!

    I've heard guys needing to place a switching type regulator on there along with a large cap then filter/shield this for RF noise. Because of the swings in sunlight I'm told. A large external battery would work and is what I do now with this and some of my other radios. For day hikes it's no big deal but after mile 50 or so you just want to lighten the load and all that lead looks like the perfect candidate...heh

    There is a large hit in weight and bulk for the backpack doing alot of this stuff. Over the years we've spent far too much money on a ultralight 2lb 2-person tent, titanium cookware, featherweight all-fuel stove, bags and packs... and the list is an endless money pit. Doing this thing in the least weight possible is key. I suppose taking the radios with me at all is breaking this no ballast rule to begin with.

    Anyways, thanks for your help! Good to know there is great support out there.
    Steve
    · Share on Twitter
  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
    #9
    Re: Backpack portable power. Advice needed.

    Well, another weight-reduction option that - heh - lets you spend more money would be to switch to a lithium-based external battery.

    There are some models that are "lead-acid replacements" for alarm systems. They have the balancing / charging circuitry built into them so can be used in applications where you'd normally use a lead-acid. They weigh about half the equivalent lead-acid battery - and can handle being discharged more fully than the lead-acid so effectively provide more energy to boot.

    I haven't followed the discussions much, since I already have a Buddipole LiFePO4 pack and separate charger, but there has been extensive discussion of models and prices on the FT-817 Yahoo Groups forum. You could look there for links, there were several companies with them. A few people found cheaper ones on ebay, but I'm too cynical - I figure I'd get what I paid for there... Or less! :roll:
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #10
    Re: Backpack portable power. Advice needed.

    I've look briefly at those packs. They are very slick. Guess I might be able to eliminate the solar and the NiMh cells with a good sized one of those! Very pricey though, and the form factors of AA and AAA fits the other stuff like the lights and such too. But that Lithium tech is very attractive. Here's a video of just how attractive:
    https://www.youtube.com/watch?v=Nxp_Nsa54_Q
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #11
    Re: Backpack portable power. Advice needed.

    i enjoyed that video. i wonder if his hat ever caught fire?:p

    it would've been nice if he went further with it by showing the batteries and giving more details. it does sound like a good option for you.
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #12
    Re: Backpack portable power. Advice needed.

    Niel, I always get paralyzed. Even though one of those LiFePo packs could easily power this thing for a week or more I see it going dead eventually and me left on the top of the hill with no one to talk to..:D It's like I want to buy something that could keep me out there forever even though I know I'd most likely die from something else anyways...lol "Hmmm...no more food or water and I'm sick and injured, better check on my batteries." Ya' know? heh heh heh... Gotta stop trying to play Superman I suppose.

    That Lithium pack would do it but I already ponied up for the panels and I like a challenge. Even a Rube Goldberg one.
    · Share on Twitter
  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #13
    Re: Backpack portable power. Advice needed.

    Things to keep in mind;

    If your hiking, how much sun will the panels recieve? I'm from the East coast and usually hike in the woods...

    NiMH batteries can often(check their specs) be charged unregulated up to C-6-10 (1/6th -1/10th capacity)

    For lithiumIon batteries, I've found using internal charge controllers works out pretty well, I have a nokia N800 that doesn't like some USB ports, but was fine charging off of a 6V nominal .8 Amp solar panel with a simple 5V voltage regulator in line. easier to get away from extra batteries.

    Sorry I don't speak 'Ham' seams to be a strong group of ya'all here.

    Oh, and the lithium battery pack is wrapped in silver package next to his backside, that's the way they ship...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #14
    Re: Backpack portable power. Advice needed.

    "Oh, and the lithium battery pack is wrapped in silver package next to his backside, that's the way they ship..."

    i don't think so as that looks to be a 2kw linear amplifier. there is a gray package between the linear and his back that is most likely the battery.
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #15
    Re: Backpack portable power. Advice needed.
    Photowhit wrote: »
    Things to keep in mind;

    If your hiking, how much sun will the panels recieve? I'm from the East coast and usually hike in the woods...

    NiMH batteries can often(check their specs) be charged unregulated up to C-6-10 (1/6th -1/10th capacity)

    For lithiumIon batteries, I've found using internal charge controllers works out pretty well, I have a nokia N800 that doesn't like some USB ports, but was fine charging off of a 6V nominal .8 Amp solar panel with a simple 5V voltage regulator in line. easier to get away from extra batteries.

    Sorry I don't speak 'Ham' seams to be a strong group of ya'all here.

    Oh, and the lithium battery pack is wrapped in silver package next to his backside, that's the way they ship...

    Good to know info, Photowhit. Yep most of the hiking is in the forest. We like to camp at altitude as much as possible and or on the waters edge. That's where we could grab some sun for a day. No longer though that's why the two panel sets, to gather more and faster. I've seen guys hiking away from the sun with the panels strung out on their packs. That seems very unlikely most of the time from my experience.

    Still checking out those Lithium packs. Now look what you guys went and did...heh
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #16
    Re: Backpack portable power. Advice needed.

    Figured I'd close the loop on this (I loathe open ended threads). What I settled on was a 10W folding panel sold by Instapark. It supplies 2A @ 5V max verified via 2 USB ports. It supplies this on a single port.
    I chose a 10 Ah Anker Astro 3000e lithium pack. Charges at 1.5A verified. Supplies 3A verified. Is only 70% efficient though.

    It been a handy setup. Keeps me in light, comms and nav. Valuable enough in times like these.
    Attachment not found.
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #17
    Re: Backpack portable power. Advice needed.

    Ax, fire, shelter, snares, and smart phone for latest sports score--Such is a guy. :p

    -Bill ;)
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #18
    Re: Backpack portable power. Advice needed.
    BB. wrote: »
    Ax, fire, shelter, snares, and smart phone for latest sports score--Such is a guy. :p

    -Bill ;)

    LOL!!

    Hey Bill I'm glad you saw this. Can you suggest an electric heater that will run on this system? Four trees per night is a tad bit tedious ...8)
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #19
    Re: Backpack portable power. Advice needed.

    There is a wood/scrap powered camp stove that has a USB Output:

    BioLite - BioLite Stove

    And it is too small to burn 4 trees a night.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • SteveK
    SteveK Solar Expert Posts: 387 ✭✭
    #20
    Re: Backpack portable power. Advice needed.

    Hey that's pretty cool!
    · Share on Twitter

Categories