12v Car Adapter Recharger?

[recce556]

Hey guys, so I'm going on a multi-week trek/backpacking trip. I have a Brunton Solaris 6 that I plan on using to charge up my electronics (already tested and works great with all my gear so far). However, I also wanted to take a battery charger with me to charge up AA's and RCR123's (corrected) for my lights. AAA would be nice too but not 100% necessary. I'm also planning on carrying some disposables as backup.

So I wanted to find out is what you guys would recommend for a durable (and hopefully lightweight) charger that will work with either a 12V car adapter or directly with the Brunton Solaris's adapter port. I found a couple via Google but I wanted to get some feedback from people who have actually tried one. Any help would be appreciated. Thanks everyone!

 

[Lynx_Arc]

not sure how long it would take on the solar cell but if you wanted to use both get a usb smart charger and a 12vdc-usb adapter. there are a few usb chargers like the energizer duo and duracell makes a few also otherwise you will have to go for a standard smart charger either with a car cord or that had a 12v walwart and get a cable adapter for it. I used a rayovac 1 hour charger with a car adapter on a 4 day power outage and probably will do so again but do have a duracell mobile charger I just need a car adapter for

 

[paulr]

It's a little unclear what you're trying to do. If you want to charge from a 12v cig lighter socket, I like the Energizer 15 minute charger because of its speed. It's heavier than I'd want to take hiking, and uses way more power than a solar panel can possibly supply, but it should be fine for use in a car. It charges 4 cells independently, any mix of AA and AAA. The Brunton solar panel should have its own charging setup. CR123A's are not rechargeable and they may explode if you try to recharge them. There is a cell called RCR123A which is 3.6 volts (not suitable for some 123 lights) and which is rechargeable but needs a special charger designed for lithium ion cells. Simplest way to do that is get a 120 volt li ion charger and inverter that plugs into your car outlet. Another possibility is one of those universal cell phone battery chargers that plugs in a USB port, along with a 12V to USB adapter in the car. I'd be skeptical of using any type of li ion charger from the solar panel because of unknown response of the microprocessor in the charger to voltage dips and power interruptions from the solar panel due to changing cloud cover, movement of the panel, etc. I'd keep in mind that as much as we like flashlights here on CPF, normal (i.e. daylights) backpacking just doesn't require a lot of flashlight use. A small 1aa or 1x123 floody headlamp to set up your tent with at night, and a similar 1-cell throwy handheld light for when you need a little more reach, with a spare cell or two, should be plenty. I wouldn't bother with recharging systems.

 

[recce556]

Hey Guys, thanks for the info. Sorry for putting CR123, I meant RCR123 which I already have (AW and another brand).

I don't need a "fast" charger, just one that can charge. This unit will ONLY be plugged into the Brunton solar cell, not a car. An inverter would be impractical due to weight. I already have a ton of other "core" gear so the "fringe" gear needs to be light. Also, great point about the possible power flow interruption with solar and the problems it might cause with the chargers.

The backpacking I'm doing isn't going to be a normal day-hike only affair. I'm going to do a lot of night time activities so I'll need lights more than normal plus I have other items (not just flashlights) that require batteries. I just didn't want to carry around a bag full of various batteries if I could avoid it but sounds like that might be the best solution.

 

[paulr]

Just how big is this Brunton panel and how long is your planned trip? I once did a calculation and figured that solar charging only becomes worth the weight if you're going to be out there for months. (Edit: Never mind, I found the Solaris 6 on Amazon and see it got terrible reviews. I'd evem consider the 12 watt unit since the "6" refers to the most power you could possibly hope for under absolutely optimal conditions, though I see you already have the 6 watt . And the Solaris's 12 volt output which means you're going to need some dc/dc conversion scheme to charge lower voltage batteries with reasonable efficiency. But the things are lighter than I expected. I see some other interesting solar devices on brunton.com as well). Are you going to be hiking every day (i.e. trying to charge up batteries while you are walking, with the solar panel mounted on your backpack), or would you be arriving at a campsite and setting up the charging system for stationary use?

Anyway, RCR123A is about equivalent to a cellular phone battery, so if the Brunton system comes with some kind of charging interface for generic cell phone packs, just use that. You might have to concoct something to connect the RCR123A to the cellular charging contacts. If the solar pack has a USB port, there is a cheap gizmo from deal extreme that can charge a phone pack from USB, so maybe you could adapt one of those.

What do you have besides lights that run on RCR123A's? I think the options of solar AA NiMH charging are better developed than those for li ion at this juncture. In fact I'd even reconsider bringing any 123 powered lights instead of running everything on AA's. Have you calculated how much power you expect to actually use to run all your gear?

 

[BIGLOU]

Dont know about the solar thing, but I got this one from Lighthound for my WF-139. http://www.lighthound.com/Ultrafire...-for-Multi-Battery-Charger-WF-139_p_2257.html

 

[recce556]

Yeah, i don't know about the terrible reviews but I've used the Solaris 6 and it seems to work fine for what I've used it for so far. The 12 panel version is too large for what I wanted to do which is to hike with it on my pack during the day. If I get to my destination and there's still some daylight, I would keep it out and charging whatever needed charging. I'll be out for a few months possibly.

I did considering splicing some wires to make it work with my existing charger (which uses a power adapter that puts out about the same amount of watt/volt/amp as Solaris) but I was hoping for a better setup. I don't want to travel with overly hokey gear.

Getting back to AA, so what are my options for a USB pluggable AA battery charger? I'm ok with NiMH and since I can easily get a USB adapter for my solar charger, that would probably be the path of least resistance.
http://www.4sevens.com/product_info.php?cPath=297&products_id=1599

 

[paulr]

I think you're already in hokey territory even with the Solaris 6 strapped outside your pack while you walk. . I had not realized before looking at Brunton's site that it was a 12 volt panel. I'm not sure what the best store-bought solution is to charging AA's with something like that, but I may look around or think about it. It does seem to be a somewhat open need. I see Brunton also has some polycrystalline panels that appear more efficient than the flexible panel of the Solaris.

Do you have a power budget figured out? That means make a list of all the electronics you need to power, how much power each device uses and how long you need to use it for. Beyond that, I wonder if you might be overestimating your requirements for gear, lumens, runtime, etc.? Are you planning to run outdoor stadium lights or something like that? I think the idea of outdoor recreation is to get away from computers, TV, and so forth. So I'd tend to say, leave that stuff at home. Bring a few lights, a GPS, an emergency locator beacon if you're going someplace remote, but that's about it. And at night, plan on using the lights in low power mode most of the time. 5 lumens really goes a lot further than people around here seem to think, and you can run a modern led at that level from one AA cell for tens of hours.

 

[Lynx_Arc]

Getting back to AA, so what are my options for a USB pluggable AA battery charger? I'm ok with NiMH and since I can easily get a USB adapter for my solar charger, that would probably be the path of least resistance.
http://www.4sevens.com/product_info.php?cPath=297&products_id=1599

not sure how a USB charger would work as the one I have is an energizer duo that charges 1 or 2 nimh AA/AAA seems to work well enough I haven't used it that often I picked it up for $8 in case I needed one to take to an IT job one day. They did have some at BigLots awhile back for $8 probably gone though in all stores. Duracell makes a USB nimh charger too. I would make sure you get one that can charge cells one cell at a time in case you only needed one it would be faster under less than ideal sunlight situations.

 

[filibuster]

I've actually been testing a number of chargers and solar panels trying to find a good combination that will work and not break the bank doing it.

For AA battery charging I started with the folding solar panel similar to the make and design of Brunton 6 watt and found after putting meters on them and a load that your only going to get about 3.5 to maybe 4 watts output consistently and that's in full sun with no clouds in a stationary location.

To charge two 2000 mAh eneloop batteries a USB charger will use about 2.5 watts over 5-6 hours. However, for a 12v solar panel you will need to add a 12v to USB adapter which uses just under 1 watt to convert 12v to 5.5v. At 3.5 watts total you are pushing the output limits of the Brunton solar panel. That is, if you want to charge 2AA batteries in one (perfect) full day of sun.

Other chargers I've evauated are: the eneloop USB charger, the GP Mobile USB Power AA charger (which will also charges a USB device with 2AA charged batteries without the sun), a Tenergy/Lenmar Alarm Clock Charger which can be plugged into a 12v source directly as well as a USB source to charge 2 to 4 AA/AAA batteries.

I've tried other chargers too such as the MAHA C204GT, C9000, AccuManger20, Rayovac USB, GP USB Powerbank and a few no name brands with various wattage solar panels.

The Tenergy/Lenmar alarm clock charger is testing best overall for charging with small wattage solar panels. It handles the various power output conditions solar panels produce and will work with voltages as low as 3.75v up to 16v and will produce varying degrees of current to charge batteries across that whole range of voltages. At voltages below 7-8V it works best with only two AA batteries in the charge bay and will use 2-3 watts of power. Trying to charge 3 or 4 batteries at the lower input voltages will add considerable time to the charge cycle as it pauses a few seconds between charge pulses without power being applies. With two AA cells it will maintain approx 500 mA per cell of a constant but pulsed current down to 4.5V of input voltage when it drops to 300mA until it drops out complete at about 3.75v. At above 9V it will charge two AA's at 1200mA and uses 6-8.5 watts. Adding three or four total batteries the charge current drops to about 800mA/cell and the charger will draw the same 6-8.5 watts.

The testing I've done matches the specs pretty closely.

I'm still evaluating the charger and I'm not sure it's the most efficient compared to others but it seems to do a good job so far. Note: besides the alarm clock it also includes a thermometer both of which run off a CR2025 coin cell.

My next suggestion after you get a charger would be to get a 12 watt or higher solar panel if you are serious about charging batteries in the wild and need batteries charged sooner than later.

Many of the independent channel 12v chargers I've tested including the two Tenergy units and Accumanager20 use between 6-8.5 watts peak to charge 4 AA batteries at spec'd rates. The C9000 however, uses much more power than most chargers and even at lower charge rates (400mA) it's wattage usage peaks above 10-12 watts. The 2 channel MAHA C204GT uses between 3.5-4.5 watts to charge 2 or 4 AA cells.

I hope you reply back after your trip is over. I'd like to hear about your success and problems using a small solar panel to charge batteries while backpacking.

 

[hopkins]

Recce

Make a note that you'll get the best power in charge per minute between
10:00am and 2:00pm so any extended siesta breaks during that time will yield
more electrons that morning/evening charging which may be worthless as your
small panel will have to drive the charging electronics with little left over for the battery itself. You probably already knew that.

Unless you rig an umbrella like platform to hold the solaris6 exposed to the
Sun at almost 90 degree angle its probably not worth trying to walk and charge at the same time.
If any part of the panel is shaded the power goes way down or if the angle
of exposure is more than 45?degrees off.

The fuss the panel requires may make it an albatross, but maybe not if
you'll be in the desert with no trees/shade, and no wind to make it flap about.
Sorry. Just my experience.

My favorite panel is the size of a paperback book and trickle charges 3 AA's with about 10ma each in full sun. Not enough to replace the 1/2 hour use per day in a small LED headtorch, but its fun.