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Thread: Batteries and solar power charging

  1. #31

    Default Re: Batteries and solar power charging

    No this is not why expensive USB chargers don't use MPPT. They don't use it because implementation is generally expensive and when you look at low power solar charging systems, the small benefit you will get (20-25% over normal temp ranges) is not worth it. You are better off adding more panel in most cases.

    MPPT has even been implemented into chip sets targeted towards cell phone charging where maximum size is fixed and hence extracting the most power is important.

    MPPT works over the whole range of the solar panel, so while there may be points where you limit output current because the max the solar panel can supply exceeds that of the device being charged, the rest of the time that is probably not the case.


    Quote Originally Posted by StorminMatt View Post
    Keep in mind that there are issues with using any kind of MPPT when it comes to charging USB devices or 18650s. MPPT is generally used in residential, commercial, and utility systems, where rather large amounts of power can be dumped back on the grid. This is advantageous, since it improves the return on investment in the system. But charging USB devices and 18650s is different. Neither can simply take all you can dump on them. USB devices (like phones) can generally only take specific amounts of current. And 18650s (and other Li-Ion batteries) have definite limits on charging current. In other words, you DON'T want something that is going to force more current through these devices when the sun gets bright just because the power is now 'there' to do so. That's why even expensive USB chargers don't use MPPT.

  2. #32

    Default Re: Batteries and solar power charging

    There is a lot of truth to this and how effective MPPT can be versus simple PWM can come down to how much time the panel is in full sun versus shade/low power. It is possible to design an MPPT system that if effective over wide power ranges and even just shunts the panel to the load when running the MPPT switcher no longer makes sense. It's not free and not something that typically would be in an off-the-shelf generic charger, but an application specific unit.


    Quote Originally Posted by ChrisGarrett View Post
    And MPPT digital controllers have a microprocessor inside that drains power on its own, so if you're already dealing with small amounts of current, the MPPT controllers might be doing more harm, than good, vis-a-vis useable current going to your devices.

    PWM controllers for something like my 60w rigid setup made more sense, especially economical sense.

    Chris

  3. #33

    Default Re: Batteries and solar power charging

    $1000 changes everything. For that money, charging laptops is well within the realm.

    At that price, you really need to consider bulk storage. Some portability is a concern, so I suggest something in the order of a 25AH LiFeP04 12V battery. You can go smaller or larger as needed or desired.

    You are going to be into 100W+ in solar panels, again, you know what you want. Foldable will never be reliable. Go for semi-ridged that can take some abuse, but will need your life goals. On the larger ones, look for being able to replace external wires.

    Charge controller -- Pick something good (Morningstar or similar), not the cheapest. I would stick to PWM, but it's your choice on spreading money versus more panel versus performance.

    Leave budget for good cables, mounts, and an inverter and find a convenient charger that takes 12V (variable 12V). Count on replacing the charger a few times over 10 years.


    Quote Originally Posted by mickb View Post
    Hi gents I have decided for this project to stick to 5v systems and charging smaller devices, batteries up to 18650's. (Laptops and heavier items off the list, I'll use mini generators and powerpaks for home type SHTF) I'm also not looking for ultralight backpackable version so much now. Chasing something still mobile but heavier duty/more durable would be good. My budget is $1000 so after a decent setup. I don't need lots of power but would pay for the ultimate in durability. Have been checking out the lifetime of solar panels and wondered if its reasonable to assume these panels( and their electronic parts) might make the 10 year mark? I am checking out the links for goalzero etc and will see what I can come up with.

  4. #34

    Default Re: Batteries and solar power charging

    The brighter the light, the darker the shadow.

  5. #35

    Default Re: Batteries and solar power charging

    Wuups, ok for 1000$ and only looking to keep 5v electronics going, what about going modular, redundant and something like several of the Nitecore F2 and several folding panels? Then you could do something else with the other 600, 700-900$.
    I haven't used any GoalZero, but from reading the stats of watts, weight, and price, I really think one could do a lot better. Not to be harsh but I feel like they're in the Bear Grylls range of the market, that's where they are in the shelf at Cabela's anyways.
    A tube of silicone caulk and some aluminum sheet for heat sinking could make sume of the deals you can find online into something cheaper, more durable, and more powerful than many of these early pioneers that have been sitting in their brand recognition for a while now.
    Last edited by eh4; 09-21-2017 at 12:09 AM.
    The brighter the light, the darker the shadow.

  6. #36
    Flashaholic
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    Default Re: Batteries and solar power charging

    Thanks again gents, just revisting this thread. So I was looking to get some chargers that are basic and solar compatibale and won't keep turning themselves off as per some of the concerns mentioned above.

    I saw the xtra Mc1 recommended above. The literature I am reading lists the Li-on 18650 and 14500 I use but can it also be used for eneloops? Would be handy if so...

    Failing that I see the Klarus K-1 looks pretty simple and lists all the Li-on and Nimh batteries, anyone know if this would handle solar reliably?

    I'll probably pick up a few of whatever the best recommendation is.

  7. #37
    Flashaholic* ChrisGarrett's Avatar
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    Default Re: Batteries and solar power charging

    Quote Originally Posted by mickb View Post
    Thanks again gents, just revisting this thread. So I was looking to get some chargers that are basic and solar compatibale and won't keep turning themselves off as per some of the concerns mentioned above.

    I saw the xtra Mc1 recommended above. The literature I am reading lists the Li-on 18650 and 14500 I use but can it also be used for eneloops? Would be handy if so...

    Failing that I see the Klarus K-1 looks pretty simple and lists all the Li-on and Nimh batteries, anyone know if this would handle solar reliably?

    I'll probably pick up a few of whatever the best recommendation is.
    No, unfortunately, the Xtar MC1 (500mA), Xtar MC1+ (500mA/1A) and Xtar MC1+ ANT (voltage meter, 500mA/1A) chargers are all only lithium-ion chargers and don't do NiMH. If you want a smaller, cheaper charger that is a single bay, does NiMH and li-ion, but only in the AA/14500 sizes, or smaller, look to the Xtar XP1 Hummingbird USB charger.

    It does 250mA and 500mA, so it's good for the 14500/AA sizes, the 18350 li-ion high current cells, the 16340 size and the lowly 10440/AAA size.

    You can then get an Xtar MC1+, or even ANT and use those for your 18650 size li-ions, or even smaller, although that 500mA rate is probably a tad high for 16340s and definitely too high for the 10440s, if you run those.

    For about $20, you have two good chargers that work with smaller USB folding solar panels.

    Since you're in Australia, look to GearBest for the Liitokala Lii 100s and/or 202s. While they both have their deficiencies, they're inexpensive, so you can buy a few of them for not a lot of cash. Their rates are both 500mA/1A, but they are true multi-chemistry, multi-voltage chargers that double as so-so power banks in a pinch. Still 500mA is a bit high for some cells, but you're covering a lot of your bases.

    These chargers are cheap to own and if you pick correctly, you can have emergency charging for not a lot of money.

    Chris
    Convoy: S2, S2+, M1, M2, Fenix: P1D, PD32, HL30, ET: D25C Ti, SF: 6P, ZL: SC-600, Klarus: P2A, Jetbeam: BA-20, Icon: Rogue 1, L3: L10, Xeno: E03, ShiningBeam: I-Mini, Olight: i3s, SWM: D40A, M11R, V11R, Maglite: 6Ds, MMs, Solitaires, LaCrosse BC-700, Maha C-9000, XTAR VP2, MP1S, XP1, MC1+, WP2 II, NiteCore i4, v2.

  8. #38
    Enlightened
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    Default Re: Batteries and solar power charging

    Get a Goal Zero Nomad plus they just came out with a newer model last year it's super thin and pretty darn durable. And just FYI if you have a nice thrower flashlight you can actually shine it on the panel and charge whatever battery you need LOL I used my tm26 from Nightcore to charge my phone up long enough to get out a text!

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