I Want A Solar Powered Setup To Fuel My Maha MH-C800S Charger. Will This Work?

[CyberCT]

I have a Maha MH-C800S and it is my only AA charger. If I go on a camping trip for 4 days or so, and want the ability to recharge my cells away from the house, all I'm left with is the option of solar. I also have a Pila IBC charger for my 18650 batteries. I want both chargers to work OK, doesn't have to be at the same time.

I am a little confused about the whole AC / DC related to volts, amps, etc. thing works. I know they are all related, but not really how. That's not my strong point. So someone that DOES understand all that, please let me know if the following setup would work:

Brunton Solaris 12-Watt Solar Charger (comes with female cigarette lighter adapter):
http://www.amazon.com/dp/B0019OOTNK/?tag=cpf0b6-20

Duracell 100 watt DC to AC Inverter (for a cigarette lighter)
http://www.amazon.com/dp/B000U0M7OW/?tag=cpf0b6-20

Maha MH-C800S Charger (obviously)
http://www.amazon.com/dp/B000LQMKDS/?tag=cpf0b6-20

Pila IBC LiON Charger for 18650s
http://www.oveready.com/batteries-chargers/pila-ibc-lithium-charger-cc/cv-/prod_44.html

Is there anything I'm missing from the setup above to make it work? If the output of the solar panel is enough for constant uninterrupted power to the Maha charger?

 

[netprince]

You will want to skip the DC->AC->DC conversion, there will be a lot of wasted power doing that.

Look at the ac adapter on your charger, its going to say something like output: 12v 1000ma. You will use the solar charger in place of the ac adapter for your charger. For those ratings I would get a solar panel that ranges from 12-14v and provides 1500ma. The volts on the solar charger must match the maha, and the ma must be higher, the more ma the better.

Also keep in mind that any interruptions in sunlight will reset your charger, and if this happens all day it could overcharge your cells. You will want to monitor the cells and remove them when they are full.

 

[Bolster]

I'm also very interested in a solar solution for recharging, but it would have to be a hands-off, no baby-sitting solution. Based on netprince's reply, it sounds like the solar technology for recharging cells "just isn't there yet." Although I'm curious if you added a big 12v auto battery in mediation, if that would smooth things out. In other words, solar charge a lead-acid battery that can handle lots of interruptions and recharges, and then use the 12v to charge the AAs or 18650s or what have you. Sadly I have no background in electrical engineering and I'm looking for someone to "put it all together" for me so all I have to do is spend the money and hook up the wires.

 

[Aquanaut]

You will want to skip the DC->AC->DC conversion, there will be a lot of wasted power doing that.

With proper sizing, you can get inverter efficiencies of 85 to 95 percent. Google "inverter efficiencies" to convince yourself of this.

I would recommend using an inverter running off your car battery and using the solar panel to keep your car battery charged. That way you don't have to worry about overcast skies reducing solar panel output. Your solar panel should have some sort of charge controller so that you don't overcharge the car battery.

Walt

 

[Sub_Umbra]

As already mentioned, solar charging without a battery for a constant source of power is problematic.

Whatever you do with solar, junk those big, heavy, LOSSY cigarette lighter plugs and sockets for Anderson Powerpole connectors. While cigarette lighter plugs and sockets are 12 volt bear in mind that they are really designed for systems charging all the time at nearly 14 volts driven by a powerful engine fueled by gallons and gallons of fuel -- exactly the opposite of the system you are trying to make work. They were designed for use in cars where there is almost always surplus generating capacity -- again, the opposite of your situation.

Powerpoles are genderless, self wiping, high performance connectors rated at 200,000 insertions. They lock together and may be set up so as to avoid polarity accidents. They are so good that they have become the de facto standard for the ARRL. If you stick with the big clunky plugs less of the output of your panel will be utilized. That can be pretty painful in marginal installations. I use them (Powerpoles) for everything in my 12 volt solar charging setup.

There are a great many YouTube vids on Powerpoles.

Here is a good info page by a Ham to give you an idea of what they are about:

http://home.comcast.net/~buck0/app.htm

They are the real deal.

...Based on netprince's reply, it sounds like the solar technology for recharging cells "just isn't there yet."...

It's certainly not there for Maha chargers. Every one of them I've used or read about pukes and resets to default if the power is interrupted for even a fraction of a second.

...Although I'm curious if you added a big 12v auto battery in mediation, if that would smooth things out. In other words, solar charge a lead-acid battery that can handle lots of interruptions and recharges, and then use the 12v to charge the AAs or 18650s or what have you...

That's the way I do it. Then you may charge day and night with solar. I also use a RigRunner 12v distribution box. Each output terminates with Powerpoles and each is fused. I charged about 15 cells today.

I would also add an in-line fuse to protect your equipment.

 

[lightseeker2009]

I would just get a 3S Lipo pack and run an inverter off it. Its light and compact. I'm thinking of getting one myself. Allready have the inverter.

 

[Bolster]

Hey SubUmbra thanks for the info. Do you know of a list, recipe, set of instructions to build a solar recharging station? Would love to have one that could recharge all my batts, including my 12v Makita cordless tool batteries. Found this portable charging station but it leaves out the solar part!

 

[Sub_Umbra]

Hey SubUmbra thanks for the info. Do you know of a list, recipe, set of instructions to build a solar recharging station? Would love to have one that could recharge all my batts, including my 12v Makita cordless tool batteries...

Fixed solar PV installations are certainly easier to design than portable rigs. I don't think it's overly complex but I do think it's a good policy to proceed slowly if you're not absolutely sure of how you're going to do it.

The basic components are pretty straight forward. Panel > Charge Controller > Battery(s) > Fuse > Distribution Box (if you ever will have more than one LOAD) > Fuse > LOAD.

Just go slowly and try to buy parts that will maximize your output. Solar under the best of conditions is always intermittent by it's nature -- aside from clouds causing output sags remember that a night follows every day.

Just try to buy parts that will maximize whatever power is available.

YouTube is a great source of info and their syntax is the same as Google's. Whether you are setting up a fixed unit or something portable for backpacking I would recommend researching the Doc Wattson and Watt's UP analyzers so you may measure and see what is really going on with your system -- every little bit counts with solar -- whether you're operating fixed or mobile. Those two units are very similar and both are very popular with the RC and Solar crowd. The backpacker probably wouldn't want to carry one but it's not necessary as all the testing may be done at home.

So:

-- Research
-- Try not to buy anything you'll later outgrow
-- Buy the best designs of the highest quality you can afford
-- Analyze, experiment and maximize every component
-- Go slowly and try not to let out the 'Magic Smoke'

 

[cckw]

I had a similar question a while back and after talking it through the only reliable option was a 12v battery as a stabilizer. so panel to the 12v, then to the Maha (or in my case a durecall CEF23). motorcycle size 12v or car size. whatever you prefer.

 

[Sub_Umbra]

I agree and in all fairness what netprince and I have been saying about Maha is also true of many other chargers -- they all seem to lose their settings from power interrupt.

I actually prefer charging from my 12 volt system as I live in an area where the Mains suffer through sags and minor interruptions quite routinely. The 12 volt is rock-stable through all of that.

 

[Aquanaut]

Do you know of a list, recipe, set of instructions to build a solar recharging station?

Here is a video on installing a solar panel charging station. It will show you the basics.

Let me add that a lot of cars shut off their cigarette lighter plugs when turning off the ignition. Both of my cars do this.

 

[CyberCT]

So there really are no recommendations for a premade mobile solar setup? Like to take camping? I would have to buy a separate car battery I guess.

 

[Sub_Umbra]

I've used a small, stand alone unit in an emergency and got good use out of it. It was a 'dumb charger' and I knew that I had to be aware of what was happening. I think the message to take away from this thread is that it doesn't matter how smart your charger is, you won't be able to get it's full functionality out of it without a continuous power source. It's not that hideously smart, programmable chargers won't work without a storage battery between the PV panel and the charger -- it just won't work right without your thoughtful supervision. You just have to treat your smart charger like a dumb charger and do all of it's thinking for it.

Most of the issues stemming from this old, old issue of chargers losing their program because of a power blink could be solved by adding 20 cents worth of flash memory to the charger -- just enough to hold the user's settings.

Gee, with 20 cents worth of flash Maha could stop lying about their chargers being Professional Grade. Sheesh, don't even try to use one connected to a Third World power grid. Some charger company will eventually figure this out and kick everyone else's butt -- but don't hold your breath.

 

[Ardillakilla]

So there really are no recommendations for a premade mobile solar setup? Like to take camping? I would have to buy a separate car battery I guess.

No personal experience but this crossed my desk yesterday:

http://www.goalzero.com/

 

[lightseeker2009]

What about my suggestion for a Lipo pack to use on an inverter? Those 3S packs are 11.1V, 12.6V when off the charger. An inverter works down to 10.0V. If you get a 5000mah pack you will be able to run a 8-cell Maha charger for some hours. And the battery is far cheaper than any solar panel. And you don't have to care even when its raining. I've heard of some people are even using these high discharge capable packs to jump-start their cars.. Currently I'm using a car jumpstart pack. Its using a 17AH lead acid battery but is a bit heavy to carry around. I'm thinking of getting a 3S Lipo pack to replace this heavy pack. It will work.

 

[HarryN]

If you are really away from all other power sources for 4 days, and you have to carry it all in, I would suggest just using energizer Li enhanced AA primary cells for the trip, and skip dragging along all of the extra stuff. Those cells are very light weight and deliver well for many AA size applications.

Cost wise, it is going to be way cheaper to take along a lot of AA energizers than to buy a solar charger and battery pack.

If you decide to stay with the R AA approach, then lightseeker2009's suggestion is very good. Skip the charger, and just direct charge off of of the pack with a resistor to slow down the charge rate. 2S LiIons are very close to a 6 S AA NiMH charge voltage. I wouldn't necessarily do it every day, but for a 4 day camping trip, maybe its ok.

BTW- are you "packing in" carrying everything, or is this more like what we do - camping with the car nearby ? If the car is going to be nearby, then just add a marine battery to the car and be done with it.

 

[Wrend]

I'm also very interested in a solar solution for recharging, but it would have to be a hands-off, no baby-sitting solution. Based on netprince's reply, it sounds like the solar technology for recharging cells "just isn't there yet." Although I'm curious if you added a big 12v auto battery in mediation, if that would smooth things out. In other words, solar charge a lead-acid battery that can handle lots of interruptions and recharges, and then use the 12v to charge the AAs or 18650s or what have you. Sadly I have no background in electrical engineering and I'm looking for someone to "put it all together" for me so all I have to do is spend the money and hook up the wires.

Yes, this would be the ideal setup for a semi-portable "off the grid" solar charging station.

The technology is there, it just has to be used appropriately and effectively.

Using an inverter and an AC adapter for a 12VDC powered charger is a needless waste of power, and it will mean you have to use more solar panels and a higher capacity Pb just to keep up without any benefit.

The only reason to get an inverter is if you have other uses for it.

 

[lightseeker2009]

The only reason to get an inverter is if you have other uses for it.

I'm the only one in my complex that still watches tv even if the power is out. An inverter is really usable. I also use it when out camping/fishing. I use a 20W energy saver in a spotlight that is giving more than enough light for the campsite. You only need the flashlight if you must go and take a dump lol

 

[Wrend]

Yeah, that's fair. I'm just saying that if you can run your charger directly off the lead acid battery, it makes more sense to do it that way.

 

[lightseeker2009]

For sure, and cheaper