Looking for a good AA Solar charger

System · December 2011

Well the title says it all.

niel · December 2011

Re: Looking for a good AA Solar charger

no it doesn't for you don't specify the number of aa batteries you need to charge at one time. maybe one of these will fit the bill in any case,
http://www.mahaenergy.com/store/products_digcam.asp

Vic · December 2011

Re: Looking for a good AA Solar charger

Completely agree with niel,

Have used MAHA chargers for many years, and have a number of the 4-cell AA/AAA chargers with separate wall Plug-In PS. All work great, as do their NIMH AA & AAA battereis. They do have a number of different solutions.

MAHA chargers are very popular with the Ham Radio community. FWIW, Vic

BB. · December 2011

Re: Looking for a good AA Solar charger

Also, gets a bit into how many batteries, how often you need to recharge them, and where the setup will be located.

Yes, you can slow charge AA batteries (around 10 hours) with almost anything, including a home made charger/current regulator.

The bigger issue is 10 hours of full sun may not be possible everywhere/seasonally--So you have to leave the unit, outdoors and unattended in the sun for upwards of two days for a simple recharge.

If you want to fast charge the batteries (1-2 hours), then you need a "smart charger" which is not very easy to find (from what I have seen) that can plug directly into a solar panel/array. Usually these fast chargers have a micro controller and need to measure the temperature/voltage of the battery over time--and probably would not like the variable output from a solar array.

So, for fast charging and/or overnight charging--Frequently it is easier to have a solar array recharge a 12 volt battery during the day, and recharge your AA batteries over night from the 12 volt battery.

But, if you need a small system--A larger array+12 volt battery+charger+cables/adapters are not very small and easy to pack/travel with.

-Bill

mejustme · December 2011

Re: Looking for a good AA Solar charger

Hi

Dont know if it is a "good way" but i just know this works for me.

I have a little solar 4 battery charger (one of those that have the built in solar panel). Takes ages for Nimh so I dont even know where it is right now.

What I do is just plug a normal 2/4 AA Battery charger that came with both 240 volt (Australia) and 12 volt auto power leads directly into a 5 watt solar panel using the 12 vot auto lead.

I use it to charge 2 AA batteries for a camera, 2 AA for a radio and 4 AA for a 3 watt camping lantern.

It starts charging around 7 am for 2 AA in summer time on the opposite side of the building from the sun and over the course of a day (good day) will charge the lot. I also charge 4 AA for another camera sometimes and it has no problems. The 5 watt panel (an old amorphous one) sits in the window and only really gets a few hours direct sun a day. I also plug in a torch with built in 3 AA battery pack into the same 5 watt panel and it does fine with the lot. (the second 4 aa camera would need two days for the lot but be useable for more than that with normal use). In any event I have not had to use any of the mains chargers for any of them for ages.

The charger I use is made by Hahnel. The 5 watt panel is a little down in power for the rated input of the 240 volt power supply but the output is about the same as full sun....nonetheless it works, even without direct light and works well enough for all those things to not have problems.

Neil

mike95490 · January 2012

Re: Looking for a good AA Solar charger

I use a Maha C401 aa/aaa Charger connected to a 12V battery with it's car cord. And charge the 12V with a PV panel. The Maha is a reliable charger, with hi and lo charge rates.

Photowhit · January 2012

Re: Looking for a good AA Solar charger

Most of the suggestions are not solar chargers, we have had several threads about this subject.

If you look into NiMH batteries many can take a c/8-10 continuous charge with out damage, so if your charging a 4 AA batteries you can just connect a 6Volt, 4-5 watt panel to 4 in series and likely be fine or do minimum damage.

Here's a prior thread where I provided a couple links, though I spent very little time hunting;

http://forum.solar-electric.com/showthread.php?7139-help-with-smart-nimh-solar-charger&highlight=aa+nimh

mike95490 · January 2012

Re: Looking for a good AA Solar charger

The problem is, most "solar AA chargers", as shipped, are worthless. Unknown electronics/charging circuit, paired with a hopelessly small PV, that will take several days to recharge the batteries. So, getting a panel of a couple of watts, would be the first thing to do, then mate that with a good controller circuit and you are in business.

bmet · January 2012

Re: Looking for a good AA Solar charger

mike90045 wrote: »

The problem is, most "solar AA chargers", as shipped, are worthless. Unknown electronics/charging circuit, paired with a hopelessly small PV, that will take several days to recharge the batteries. So, getting a panel of a couple of watts, would be the first thing to do, then mate that with a good controller circuit and you are in business.

I purchased a 'solar' AA battery charger from Radio Shack a few years ago, and used the recommended RS nicad re-chargable batteries. They never seemed to have enough juice to operate anything, even after a whole day of sunlight. I chunked the thing into a box, and is still there today.

Sparkletron · January 2012

Re: Looking for a good AA Solar charger

I agree that MAHA makes good chargers--but not all of their chargers are 12v, and I would avoid any charger that requires a separate power brick and cannot accept 12v directly into the charger itself. I also agree with those who say that you should avoid all-in-one solar chargers. Instead, pick a great charger and then get an appropriate PV setup to power it. If you want a turnkey solution, consider GOALZERO.

niel · January 2012

Re: Looking for a good AA Solar charger

i have this 6 battery charger and it does have the 12vdc input.
http://www.gnbatteries.us/servlet/the-265/IC-dsh-U6S1234-dsh-LED%2C-hitech-charger%2C-aa/Detail
the wall adapter is 12v at 1800ma and it comes with a car adapter too. it will charge aa batteries fairly fast as you can see by the chart and after charging it automatically places the batteries on a float charge. if you need more batteries than this you can opt for 2 separate chargers like this to keep the ability to charge from 12vdc.

as to a pv to feed this it would need to provide the 1.8a and then some due to efficiencies and losses. this will be about 77% efficiency from the pv alone so 1.8/.77=2.34a minimum from a 12v pv or roughly a 40-45w pv. if other losses from wires and charge controller are considered then going 50w or higher is in order.

i think there isn't much more to say on the subject without further input from the op and at that we may have already covered that ground without his input.

mike95490 · January 2012

Re: Looking for a good AA Solar charger

As reported from Slashdot, Nokia just tried to to get a solar backplate to work on a phone, it doesn't.

"Nokia's research into solar-powered cell phones ended with a (barely audible) thud. Under the best of conditions researchers were able 'to harvest enough energy to keep the phone on standby mode but with a very restricted amount of talk time,' Nokia wrote in a blog post on Tuesday. Not surprisingly, the prototype phone, which had a solar panel on the back cover, performed better in Kenya than in other testing locations, like southern Sweden and the Arctic Circle."

http://www.itworld.com/networking/237289/nokia-phone-charging-using-solar-power-comes-many-challenges
http://conversations.nokia.com/2012/01/03/solar-charging-panel-generates-call-time-for-test-team/
http://solarcharging.nokia.com/

Solar PV power is not very dense, and proper panel orientation to the sun is critical.

Cariboocoot · January 2012

Re: Looking for a good AA Solar charger

Why would anyone think that fitting a solar panel to a cell phone would help? The area available is very small, and rarely is it pointed directly at the sun. Most of the time cell phones are either in your pocket or purse or smack up against your ear with your hand neatly covering the back. I can not imagine a situation where the phone-back panel would be exposed to enough light to make any significant difference.

Must have been a government-funded research project.

niel · January 2012

Re: Looking for a good AA Solar charger

i'm confused as to who mentioned a phone. the op only asked for a solar aa charger with no mention of the application of the aa batteries.

Cariboocoot · January 2012

Re: Looking for a good AA Solar charger

niel wrote: »

i'm confused as to who mentioned a phone. the op only asked for a solar aa charger with no mention of the application of the aa batteries.

Mike did, in the post just before mine.

I know; I'm straying away from the subject again.

mike95490 · January 2012

Re: Looking for a good AA Solar charger

I mentioned it, because one of the big dogs (Nokia) had tried it, tested, and gave up on it, panels randomly moving around, just don't work well. Even for camping, you need to prepare a site to park the solar at. Carrying spare batteries is easier, for the first week at least. But roll up, fold up, 5 or 10 watt panels are basicly worthless for anything other than keeping a cell phone or tablet on standby, alive.
That's my opinion.

bmet · January 2012

Re: Looking for a good AA Solar charger

I used to buy solar walkway lights. I would buy, be disappointed, then buy the next generation, also be disappointed, wait a year, buy again, and be disappointed. One thing these solar walkway lights all had in common, was they had an internal AA battery. In all cases where mine stopped working, moisture had gotten into the device, or the plastic faded to opaque. Remove the plastic, replace original AA, and you'd have something that wouldn't be 'good', but perhaps good enough.

PNjunction · July 2012

Re: Looking for a good AA Solar charger

I like how the PowerFilm AA solar charger works for me. (AA only, not the usb port version)

It bulk charges at about 300 to 400ma, and then at around 80% SOC, floats them. (checked on a Maha 9000 analyzer with a discharge capacity test) The 4 are charged in pairs, although I would have liked individual charging. Basically when the charging led says done, you need at least 2 hours more for trickle to get them really fully charged.

I don't think they are using delta-v charge termination, because they seem to indicate done somewhat early, and then require a few hours of trickle. Maybe this was a safety feature so you don't go into a bulk-charge loop on fully-charge batteries if the panels goes in and out of shade. My Sanyo eneloops seem to be happy with this charger when I really have to go portable.

Looking for a good AA Solar charger

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