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Any recommendations on a large solar power bank?

  • Nick10974183 Friday, March 17, 2017 1:05 AM Reply

    Greetings,

    I can see on the many reviews from so and so satisfied customers, that many have problems with solar charging (as its not working at all) and that the battery capaity is far far from the stated capacity.
    I need a larger solar power bank to run a remote Raspberry Pi, that would actually charge on solar.
    So any recommendations of an honest product?

    Thanks


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  • Ignatus Sunday, April 23, 2017 3:52 AM Reply

    Never seen or heard of any good quality Solar powerbanks serving this particular consumer segment.


    The only solution is to DIY one. I'm currently building one with variable voltage output.


    - Most probably a bit oversized for a RBPi .. mine is to power a laptop or two.


    So, if you have a soldering iron, some smaller tools and persistence...  custom powerbanks are easy to build!


    Unfortunately, my thread looks messy, went off-topic many times and the project is not yet complete due to various reasons - ranging from lack of time to play (build it) and waiting too much time for stuff from China to arrive...


    Lot's of info in there and I think I'll complete my project in the coming days / weeks.

    http://club.dx.com/forums/forums.dx/threadid.1467557


    Anyhow, if you have sufficient funds available, easy access and fast delivery options of electronic components via one of the better known bigbox retailers...


    - Then you could easily build yourself an awesome, high capacity solar powerbank over a weekend, even as an electronics novice!


    Greetings,

    Ignatus

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    post edited by Ignatus on 4/23/2017 at 10:19 AM
  • Nick10974183 Friday, April 28, 2017 1:04 AM Reply

    Hi Ignatus


    Well the reason for the "oversize" is that i from time to time might need to fire up som 9-12V gear, controlled by the RP.

    So my idea was to throw in a big a.. solar power bank, then run one of its outlets trough a buck-converter to get the e.g. 12V. It could be a fan, an it might have to run one 30 min a day.


    Nice project you have made. I could heat up my old soldering iron, but i rather "just" purchase a ready made SPB. As the funny part, for me, is to make the controls ect.

    So i'm still looking for a SPB


    But thanks for your link and interrest :)


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  • Ignatus Friday, April 28, 2017 1:21 PM Reply

    @Nick,


    Yes, of course the monster that I'm building is total overkill for a Raspberry + a cooling fan.


    However, since you've already mentioned a buck converter ... it really sounds like a potential DIY project to me ;) 


    I seriously believe that there is no decent quality, ready-made solar-powerbank available. I've looked for years on that "rainforest" website and other bigbox retailers.


    They all use bad Lipo charging implementations (risk of destroying the already super low quality Lipo cells)), low quality / generic brand Lipo cells  (risk of fire) and always an ridiculously undersized, low quality solarpanel (will take weeks to charge if ever).


    Anyhow, if you ever change your mind - I'd be happy to help you calculate your exact power requirements, help you with a shoppinglist and guide you through putting it all together, just send me a PM.


    It is really easy as long as you can tell apart the colors black and red, as well as these 2 symbols: 


    " + and - "


    Also, if you are fine with stuffing all the parts into some Tupperware, it takes for a novice most probably around 2 hours of work to wire up the few parts and hot-glue all into place.


    - Won't look as great a ready-made one, but outperform. it by 10,000%.



    Have a great weekend!





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  • Nick10974183 Sunday, April 30, 2017 12:28 PM Reply

    Hi Ignatur


    I'm actualy considuring your project, but as i dont want the hassel of hunting down good lipo cells, i'm thinking of either using regular NiMH cells, and as these get in size C or D it should be posibel to pack a good volume energy. Plus you can get battery box cases with soldering connectors on, for AAA-D size.

    I think it might be easier to get a good quality MiMH, rather than lipos

    Or using some kind of a lead battery, 12V - and then 'buck down' rather than up.

    Of cause using the maintenance free/sealed type, like you use in garden stuff, scooters, RC gear.

    Both type are haveing some more forgiving characteristica when it comes to chargeing, rather than lipo's

    And futher more on the lead type, you will not depleted/damaged if you have to pull a high start current from it, which might be the case with powering up 12v stuff. I'm not think of my fan, but in the future it could be the a pump ect.

    Then i would be down to just a good solar panel, any you can recomend?


    Skærmbillede 2017-04-30 06.22.53.png

    Nice slim battery

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  • Ignatus Sunday, April 30, 2017 4:51 PM Reply

    @Nick10974183



    Well, as for NiMH cells - my preferred choice is Panasonic Eneloop.
    However, charging device and algorithm is more complex for NiMH cells than Lead and I’ve never seen a ready-made NiMH setup that includes solar. - Which doesn’t mean that one can’t build one.

    I don’t know anything about your project requirements. Will you be around to manually connect and disconnect the solar panel for charging?

    As for solar panels…I found some  decent ones for my project. However, for understandable reasons, it is against the rules to discuss and link here items that are not sold by DX. - Once you reply to my private message, we’d be able to communicate privately.

    In regard to cranking amps, Lipo batteries outperform. all Lead batteries easily maybe with the exception of deep winters. I’ve once cranked an old Pick-up truck with a $20 Lipo which was roughly the size of a palm-sized flashlight and estimate that the truck’s starter motor was pulling at least 60Amps.

     - No palm-sized lead battery can deliver this king of energy, ever.


    However, if you want the charging setup to be easy (no need to be present to plug-in or to disable the solar charger manually and no need to build an automatic solution from semi-scratch) , and  if portability/size doesn’t matter … then a regular lead-acid battery or sealed would most likely be your best choice and not break the bank.


    OKAY!

    I wrote this message based on an email notification that I got from DX. That email didn’t show the image of that lead acid battery that you’ve posted. Then I came online to post my reply here and seen your desired lead acid battery pic.

    That battery has a capacity of  just 2.1Ah which is tiny. Let me know power requirements of your Raspberry and the fan . How many hours per day/night, which model and it runs on 5Volts?

    Depending on the specific Raspberry model and enabled ports,  they can consume anywhere between 80-750mAh, add another 50-100 mAh for a fan if it is a cooling fan for the Pi - by the way there are 5V fans available for the Pi.

    apipower.png




    However, you were not clear if the fan is for the Pi. Power consumption would further increase for any added USB devices. Also, all buck and boost converters usually add at least another 10% loss to a system. Also note, all 5V power banks have inbuilt already a boost converter to boost the Lipo voltage from 3.7 to 5V. -Boosting that with another booster to 12V is not very realistic.

    Anyhow, if your Pi + fan were to consume around 1000mAh  = 1Ah = then your slim, sealed Lead battery with a 2 .1 Ah capacity would last for  2 hours at 12V and possibly around 4 hours at 5V with a buck converter.

    Also, I don’t think that a lead acid battery would be recharged within 2-4 hours (via solar) without boiling it. -Only exceptions are large Marine Deep cycle batteries.

    You may need to consider a larger Lead-acid battery and a 50 or bigger watts Solar panel to be able to recharge your battery sufficiently in a single day (if there is enough sunshine) if you run a newer version PI for 10 hours a day or longer.


    By the way for the Lipo cell  form. factor 18650  DX also offers battery holders with leads attached- if you are hesitant about soldering.. example: SKU: 366171 

    Good Lipos are easily available online, if you have access to the Amazon website and live in Europe or the US. I’d be happy to recommend some if you decide to go this way…


    You also mentioned that you may want to power up other 12V devices with your setup. Please let me know the details before I give you any solid recommendations.

    I’d really need way more details to be able to help you.

    I hope you don’t mind me me asking about your location - you may also reply via PM if its not something you'd want to share in public:

    1.) Where do you live? Sunny Africa, NY or the rainy UK?
    2.)Where will the solar panel be installed? Outdoors or indoors behind a window?
    3.)Does it rain or snow in your place?
    4.)How much sun is there in the winter?
    5.) How mission critical is your project? -Will people die OR YOUR BUSINESS SHUT DOWN if your Raspberry runs out of power?
    6.)Will you be around to manually connect and disconnect the solar panel for charging?
    7.) Let me know power requirements of your Raspberry and the fan . How many hours per day/night, which model and it runs on 5Volts? but fan on 12V? Its a PI cooling fan?
    8.) Other 12 V devices you may want to power?
    9.) Any USB devices connected to Pi? If yes what type and usage duration per day?
    10.) HDMI port connected to PI and in use?

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  • Nick10974183 Tuesday, May 02, 2017 2:16 AM Reply

    Hi Ignatus


    That you very much for your nice and detailed write up. :) These days i'm bit short of time these days, traveling.

    So i return in a while.

    For power; I'M planing to do some real life tests to figure out what i need. (Btw i have changed bit of the scope for box. It will be my "do it all, outdoor-away-from-power toolbox" thats why i write i might have to drive a pump ect.

    Btw do you remember the constructions boxes; gray buttoms, clear plastic at the top - i just cant remember the name of them. Thats what want to throw the gear in, with a solar panel.


    :)


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