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Discussion Starter · #1 ·
Advice needed.

How would I recharge small aaa, aa, d and c-cell batteries using a 60 watt solar panel?

What are the best type of rechargeable batteries to use on board in the tropics?

Thank you.
 

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Telstar 28
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Nickel Metal Hydride and get a 12vdc battery charger.
 

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Discussion Starter · #3 · (Edited)
Nickel Metal Hydride and get a 12vdc battery charger.
Let me clarify. How would I connect a solar panel to a small battery charger like this one, which is designed to be plugged into a standard 120v household receptacle. Can this be done? I would be using it on an old boat that has no electrical system whatsoever. Nothing.

Perhaps there is another small battery charger specifically designed to be hooked-up to a separate solar panel? (I've seen the all-in-one solar/charger units and they're pretty flimsy. I would rather not go that route.)

 

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Telstar 28
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You could buy a solar-powered battery charger. They do sell them.
 

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Old Fart
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Let me clarify. How would I connect a solar panel to a small battery charger like this one, which is designed to be plugged into a standard 120v household receptacle. Can this be done? I would be using it on an old boat that has no electrical system whatsoever. Nothing.
No, you can't connect a 120 volt charger to a dc output from a solar panel. Lowes has a good 12 volt charger for LiMH batteries that will plug into a cigarette lighter socket. I used one like it all last summer and was very pleased with it.
 

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LoTech,
I would look into the MH-C9000 charger and a 12V adapter. It's less than $50 and looks very functional. I don't know what the actual input specs are as the manual lists 12V, so you may need a constant voltage regulator (Battery) connected with your panel.

I have an Energizer quick 12V charger that was probably $40. It'll take 11V to 16V input and charges in 15 min. But for the money, I'd rather have one where I can quick charge when I need it and slow charge when I don't to extend the life of my batteries.
 

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Discussion Starter · #7 ·
This MH-C9000 charger is is pretty slick. And yeah, it operates with an optional 12-volt DC cigarette lighter adapter.

My solar panel has clip-on leads for easy attachment to a 12 VDC battery. I wonder if I can connect it directly to this charger?



LoTech,
I would look into the MH-C9000 charger and a 12V adapter. It's less than $50 and looks very functional. I don't know what the actual input specs are as the manual lists 12V, so you may need a constant voltage regulator (Battery) connected with your panel.

I have an Energizer quick 12V charger that was probably $40. It'll take 11V to 16V input and charges in 15 min. But for the money, I'd rather have one where I can quick charge when I need it and slow charge when I don't to extend the life of my batteries.
 

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Old Fart
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I really don't know a lot about it but I would worry about lower that adequate voltages during cloudy times causing the charger to try to pull higher than normal amperages and burning the charger out. You really need to use the solar panel to charge a small wet cell battery and run the dry cell charger off of that when it is fully charged. Anything else is risky.
 

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Telstar 28
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I wouldn't. Most 12 VDC solar panels are 18 VDC at full sun. That's generally higher voltage than most 12VDC systems will put out and may damage the charger.

This MH-C9000 charger is is pretty slick. And yeah, it operates with an optional 12-volt DC cigarette lighter adapter.

My solar panel has clip-on leads for easy attachment to a 12 VDC battery. I wonder if I can connect it directly to this charger?

 

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Discussion Starter · #10 · (Edited)
The charger is discounted to $35.00 so not much of a financial risk. If the panel puts out an occasional 18VDC instead of 12, perhaps adding some sort of mini voltage regular would be easier than using a storage battery?

I found one here for $13.00:

The RG12 Inline Voltage Regulator delivers true, stable and filtered 12vdc voltage with capacity up to 850mA of current draw. If offers a cost effective solution for powering many of our LED products from higher DC voltages such as marine, automotive, recreational and power sports vehicles, solar products, lead acid 12v batteries and Class 2 type transformers (AC to DC adapters) which all produce unstable voltages from 13.5 to 17 VDC. Most 5mm LED products require a true 12.0V DC regulated power supply and therefore, these unstable voltages will damage the LEDs and cause failure.
 

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Cabin boy
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You can buy small inverters for $10-$20 [at Costco, for example] that will convert 12v into 110v that your charger wants.

I agree with DS and SD. You need a battery between the solar panel and the whatever device you use to charge the batteries. You can use a small 12v motorcycle battery.
 

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You need a 12v battery in the system to even out the voltage fluctuations. The charger wont work without this. A 60W solar pannel is a lot to charge a small batteries. 5 to 10W would be enough.
With 60W and a 12v gel cell battery you have plenty of energy to run lights radio instruments etc if you want.
What are the best type of rechargeable batteries to use on board in the tropics?

Thank you.
Sanyo Eneloop are the best rechargeable batteries. They have a low self discharge rate and long life. There are many very poor quality rechargeable batteries that give many people the impression that they are not worthwhile. The quality products are vastly superior and only slightly more expensive.
 

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Lotech, I'd vote for just buying a small solar battery charger for them. If you plug something into an inverter hanging on the solar panel, it may or may not work, as the inverers are designed to run off 12V "pure" DC from a battery or alternator in a car, and all sorts of gizmos make all sorts of "not quite pure" 12V DC and 117 VAC. (110/120 is really 117 in the US, but that's a whole other story.)

Easier to get "one box" that holds the batteries and sits in the sun to recharge them.

Having said that...yes, you can cobble together all kinds of chargers, but the dedicated ones often do a better/faster/safer job with NiMh cells today, and adjust to handle NiCd and NiMh alike. (There are some differences that sometimes can be ignored, sometimes not.)

One thing I'd suggest no matter how you recharge them: SHOP CAREFULLY the batteries are not at all the same. I've got no-name chinese NiMh cells that go dead after 3 weeks sitting on the shelf, while Japanese name brands like Panasonic hold more than 1/2 their charge after six months on the shelf. Yes, I'm willing to pay Panasonic twice as much for that.

And there's a company calling themselves "Targus" selling junk batteries--which is not related to the outstanding Targus/Kensington company that sells all sorts of computer and electronics equipment.

If you haven't bought the batteries yet, contact the maker and ask them up front "What is the self-discharge rate? How long can I keep these on the sheld and how much power will they still have?" If you use 'em up daily and swap, that won't matter. If you charge 'em and expect things to last for a couple of weeks (like a pocket radio) with intermittent use...Yeah, it makes a big difference. Flashlight in the drawer? BIG difference.
 

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Lotech, I'd vote for just buying a small solar battery charger for them.
Most of the solar battery chargers are poor with little regulation and very slow charging times. Useful if you are in the middle of nowhere and want to top up your camera batteries and a compact low weight charger is important, but not a good option for rechargeable on a regular basis.
A solar panel 12v battery and regulator is a much better, but bulkier and more expensive option.
 

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The manufacturers only offer discharge rate info for the ideal temperature of 60 degree F.
The good quality LSD rechargeable batteries, such as Enoloop are still OK after 6-9 months at real world temperatures. Rechargeable batteries benefit from some use and if the batteries in a particular device, do to need to be replaced more often than every 6months or so you are probably better using non rechargeable alkaline or lithium batteries.
 

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"The manufacturers only offer discharge rate info for the ideal temperature of 60 degree F."

So? That still beats nothing. At a more typical 74F the self-discharge will still reflect a similar comparison between products.
 

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Discussion Starter · #18 ·
The good quality LSD rechargeable batteries, such as Enoloop are still OK after 6-9 months at real world temperatures. Rechargeable batteries benefit from some use and if the batteries in a particular device, do to need to be replaced more often than every 6months or so you are probably better using non rechargeable alkaline or lithium batteries.
Right. After re-reading the Sanyo Eneloop info, the batteries have a "normal operating range" up to 140F. Looks like it's not much of an issue.
 
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