recharging AA rechargables without inverter (?)

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notsobright
notsobright Solar Expert Posts: 247 ✭✭
how can I charge rechargeable batteries directly from 12v source? I dont want to waste any juice using an inverter if possible.

also intrested in charging a small12v battery from a larger one (motorcycle/car) is this possible? thanks

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  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    Well the easiest thing to do is buy a good 12v charger. I prefer the MAHA 401, I have three of them connected to a 12v battery that powers our cable modem, router, security system and these chargers. They are pricy, but I have yet to find a better straight out charger.

    http://www.mahaenergy.com/store/viewItem.asp?idProduct=178

    Whatever charger you get make sure it has independent charging channels for each cell and Delta V cut off. Many of them use 12vdc as the power input, almost like they were thinking of us :)
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • notsobright
    notsobright Solar Expert Posts: 247 ✭✭
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    Re: recharging AA rechargables without inverter (?)

    thanks Brock, I wasnt aware they made one like that.
  • anotherfarmer
    anotherfarmer Registered Users Posts: 7
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    Re: recharging AA rechargables without inverter (?)
    how can I charge rechargeable batteries directly from 12v source? I dont want to waste any juice using an inverter if possible.

    also intrested in charging a small12v battery from a larger one (motorcycle/car) is this possible? thanks


    Another option is to convert a more conventional charger. Most use a 'wall cube' type of input, which is converting 110 V AC to 9 or 12 V DC. You can often get away with plugging these straight into the 12 V system, though I usually opt for using a DC to DC converter - like the cigarette plug power sources you can pick up at Radio Shack. Same solution for cordless phones, answering machines, anything with a AC to DC wall plug.

    I have charged smaller 12 V batteries directly from my battery bank, but I doubt that it is effective as more than a way to get the cycle, in your case, started.
  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    I'll thank you as well, Brock. Your post reminded me I have been meaning to buy some more batteries as well as a charger for a while. I'm forgetful...

    That is a nice charger. I was kind of leaning toward the "fancier" models they have, but after some digging through reviews in various places finally found the "wall wart" for those outputs both 18V and 20V. Yuck. It is also apparently somewhat noisy in the HF bands, which is undesirable as well for my ham shack.

    The 401, though, looks great. Standard coaxial power plug instead of a DIN plug, and it appears the unit itself can run on 9-15V? I had to dig a bit to find a decent pic of the auto adapter, it doesn't appear to be a DC-DC inverter, just a straight-through plug with an LED in it. Is that correct? If so, then it's perfect! :) (I don't want to use the auto adapter - am going to plug the thing straight into my DC power strip if possible.)

    And another mess of AA batteries on the way too... Very nice how capacity has increased since the last time I bought them!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,532 admin
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    Re: recharging AA rechargables without inverter (?)

    Really look around when you buy NiMH AA batteries... There are many counterfeits out there--and many of the >2,000 mAH batteries seem to have very short cycle lives.

    The Sanyo Eneloop brand seem to be pretty consistent and have a much lower self discharge rate (some other brands are out now--typically called "Hyrbrid" or "pre-charged" rechargeable batteries).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    maha isn't the only company that makes chargers that work off of 12vdc as i found out yesterday. a company that normally carried the maha stuff didn't this year at a local hamfest. upon questioning them on it they told me they were having too many problems with them and have stop carrying them. i bought this charger from them that's made by hitech,
    http://www.onlybatteries.com/showitem.asp?ItemID=14657
    the link isn't the company i bought from as their price far exceeds the nominal $60 this chargher is supposed to be and mine was even $20 cheaper at the hamfest.:D i used this to better iilustrate the specs on the charger.
    for those that may be curious, i got mine from dcace.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    http://www.thomasdistributing.com/ is my favorite for both batteries and chargers of all types. They often have links to manuals in their description of the gear.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    thomas dist. has been mentioned on here many times, even by me for informational purposes, and a search on maha will lead to them too, but they don't carry the charger i just mentioned (after my finding that the company i bought from had dropped maha products due to problems with maha products) so maybe toning down the plugging for thomas a bit is in order as you reached a bit to do the plug. i thought it a good option for others to know where they can get another charger that is 12vdc capable and i don't think it warranted a thomas plug, but your post will stand as it is all just imformational options for people. i just thought another option was good to know besides the usual ones we've mentioned in the past.
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    Here is a link to a list of great threads over on Candlepower Forums. They have done quite a bit of testing on chargers and batteries with good data to back it all up. It is worth taking a look at; the top link is for chargers.

    http://www.candlepowerforums.com/vb/showthread.php?t=133440
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    brock,
    thanks for even more options. i see mine isn't listed among those tested and i wonder if it's a rebrand of something else. i may dig further into it another day.
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
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    Re: recharging AA rechargables without inverter (?)

    There are generic chargers out there that can be had for less than $20 and usually include four AA NiMH batteries. They can charge up to two pairs of batteries at a time and connect directly to a 12v source. I bought two of them about four years ago and they have worked flawlessly (I'm still using the original batteries that came with the chargers). I think there's a policy against posting eBay links here (?), but do a search there and you'll find a selection of them.

    By the way, you can often tell the quality of a rechargable battery by its weight. A NiMH battery that feels like a carbon-zinc battery is probably not going to last very long (i.e. Harbor Freight).

    Marc
  • notsobright
    notsobright Solar Expert Posts: 247 ✭✭
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    Re: recharging AA rechargables without inverter (?)
    Brock wrote: »
    Here is a link to a list of great threads over on Candlepower Forums. They have done quite a bit of testing on chargers and batteries with good data to back it all up. It is worth taking a look at; the top link is for chargers.

    http://www.candlepowerforums.com/vb/showthread.php?t=133440


    thanks Brock! very helpful info. (candlepowerforums.com) what an incredible wealth of info there!

    I ended up getting the MAHA401

    seems the top charger is the MAHA C9000 check this thing out!

    http://www.mahaenergy.com/store/viewItem.asp?idProduct=423

    AND the manufacturer rep has been posting over on those forums and actually listening and designing new features from users input/feedback there!

    http://www.candlepowerforums.com/vb/showthread.php?t=145727

    Id like to get one at a later date but the 401 is better suited for just standard recharging and its easier to use.

    I also got their 490 for 9v batteries http://www.mahaenergy.com/store/viewItem.asp?idProduct=364

    very please with both of them so far and they also have 3 year warranties


    Ive learned quite a bit about the batteries themselves there too. I might hafta join. thanks again Brock.

    Another option is to convert a more conventional charger. Most use a 'wall cube' type of input, which is converting 110 V AC to 9 or 12 V DC. You can often get away with plugging these straight into the 12 V system, though I usually opt for using a DC to DC converter - like the cigarette plug power sources you can pick up at Radio Shack. Same solution for cordless phones, answering machines, anything with a AC to DC wall plug.

    I have charged smaller 12 V batteries directly from my battery bank, but I doubt that it is effective as more than a way to get the cycle, in your case, started.

    Ive been thinking about this, what range is safe for use directly from 12vdc source that is PV powered and occasionally gets upwards of 15VDC when charging?

    Ive allways thought when the specs printed on the wallwart shows output in milliamps that a direct line from a big 12vdc battery would be too strong. how can you determine this?

    I have a recotron adapter/converter but its pretty old and doesnt have a USB plug (or 5v) output. I need to find a modern replacement for that unit too and still looking for info on a small battery to battery trickle charger.

    thanks
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: recharging AA rechargables without inverter (?)

    notsobright,
    many of the chargers that have wall adapters are able to be used with a solar pvs, cc, and 12v batteries as a system plugged into the charger rather than the wall adapter. some even have car adapters so that you can use a cigarette lighter to obtain the 12v from a car electrical system. the charger will specify what it requires or you can see the requirement on the wall adapter itself. some of the chargers that can handle 10 aa batteries often require around 17 or 18v, if memory serves, so this won't work from 12v. if the charger accepts say about 14v or 15v then often the problem is just putting a proper connector onto the wire from your system (fused of course) and getting the polarity correct. if you lack the skills or knowledge to do this then please don't do it yourself.

    lorelec,
    my charger will charge between 1 and 6 batteries individually and that makes for a better charge to each cell.