Sometimes you just want to get it done, and done swiftly.

Or at least reasonably swiftly. Most chargers are pretty slow, and take hours to recharge the batteries, even the smaller ones.

This can be very inconvenient, or even non-viable at times. It's just too slow.

There is plenty of juice available at most outlets (often it's 20 amps at 110 volts, in the US). Yet battery chargers typically make use of only a small fraction of what is available.

What are some possible solutions?

--while staying within the approach of recharging at available electrical outlets -- I've used other systems as well, like solar and generators and no-tech and min-tech and eff-tech (efficient) plus extra batteries when needed, which all have their pros and cons; but this thread is focused on this particular approach (which I like in some ways, for some tours at least).

The idea is to be able simply to plug in now and then -- and, in a more agreeable amount of time, or a significantly shorter time, capture all the electricity you need.

What are some of the options for achieving the ability to do this?

son or shimano front dynamo hub connect some battery charger to it and charge while you cycle.

Yes, and some people like those. Nothing bad to say about them here. I'm just trying to find out more aout ways of recharging more swiftly and efficiently from electrical outlets, (at least in this thread)

It's usually such a snail's pace sort of thing.

Which is fine in some situations.

Not in others though.

Pleny of juice is there at the outlets, and almost everything is in place for being able to get it done much more swiftly.

It seems like it would only take the right batteries and chargers. A fast-charging storage battery for portable electronics would be one approach. But I haven't seen any of those that fast charge well, and most of them seem to be the less-reliable Chinese ones.

Charging a set of reliable AAs or 18650s (or other batteries) in parallel would be workable. They could accept a lot more current this way.

Finding battery packs made to take a fast charge would be another approach -- some power tool packs charge very quickly, and are reliable and good for many charge cycles. But they come in odd voltages.

It would be nice to have a good battery pack like that, though, to recharge very quickly and then tap into as needed.

Twelve volts would make it easy, because of all the cigarette lighter adapters that could be used. It would be easy to get USB out (or micro-USB, etc.).

Maybe a 12-volt (or 12-volt compatible -- it could be a few volts higher and still work fine with the cigarette lighter adapter) battery from the power tool world, or from the radio-controlled vehicle world....

Maybe the Hobby King Turnigy Accucell 6 or Accucell 8 (or something similar), plus one of the quick-charging nano packs at the right voltage, plus a way to connect to a cigarette light socket -- that setup could work very well.

(I know people have used those packs for laptops, and they work well. They are very fast charging, and extend the run times of laptops. You just have to match the DC-out voltage of the laptop's power supply.)

Or maybe a 6-volt pack could give you direct USB out? If anyone can provide more information about these sorts of approaches, please feel free to post.

You could even bypass the cigarette lighter stuff and use one of their connectors directly -- the connectors that come pre-installed on those fast-charge battery packs from HK and similar outlets.

Those packs from HK are also favored by some of the electric bike builders because they provide the best bang for the buck.

USB is 5v, so even 230v would be stepped down to 5v, if the output is to not fry the gear attached to it.


I suppose you could bring a 12v battery [lead acid gel cell for Motorbikes *and charger for it,

then go from 12v to 5v while on the move.. another transformer & voltage regulator.

* or 8 D cell alkaline (1.5V) 10 rechargeable flashlight batteries (1.2v each)

(Please excuse any typos in these posts -- the system is not allowing for editing.)

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I think I'm just going to go with the HK Accucell and HK fast-charge ("high C") battery packs. I've heard enough about their use in other applications, and their effectiveness, to know they can work well here too.

Sounds like a good way to go.


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Still open to other ideas as well.

You don't say what it is that you want to charge so I'm going to make an assumption. Have you considered keeping your device/batteries charged using a solar charger? Although the trickle is rather small, it may be sufficient to maintain a reasonable charge.

The charger isn't usually the problem - its the battery. Different battery builds and qualities will have different maximum charging rates, even though the chemistry is similar. Since most electronics have batteries that aren't designed to be changed by the user - the only easy solution is an external backup battery that will accept a fast charge and has outputs to charge your other goodies when convenient.

RC Lipo batteries are available with incredible charge/discharge rates and a 11.1V battery pack or similar would interface with most 12V / 5V USB converters.

There often seems to be a fairly liberal amount of latitude when it comes to voltage.

Lithium-ion rechargeables say 3.7 volts on the label -- I just double checked this and it is there on the label -- but if you measure the actual voltage, it's about 4.2 at full charge. And it is down around 2.9 toward the end of its run when it is nearing time to recharge.

So it's actually providing a range of voltages, most of which are higher or lower than the 3.7 volts on the label.

Same sorts of things apply with alkaline, NiMH, lead acid, and other types of batteries. They all vary over a range during their cycles.

I don't know what the acceptable voltage range is for USB, maybe someone call fill this in?

It would be great to be able to charge or run devices directly from a battery without losing efficiency by having to boost or buck the voltage. It would also keep things simpler. Then again, the losses might not be to bad.... (I've heard that bucking is more efficient than boosting.)

Anyway, the twelve volts coming out of a cigarette lighter in a car will vary quite a bit (both up and down) from exactly twelve volts, so there is probably some latitude there when it comes to choosing battery pack voltage. (Seeing a discharge curve for a lead acid car battery might help here. If anyone finds one, or knows more, please post.)

The HK (lithium) battery packs come in 7.4 (2 X 3.7) volts, 11.1 (3 X 3.7) volts, 14.8 (4 X 3.7) volts, 18.5 (5 X 3.7) volts, etc.

I'm thinking that both the 11.1 volt and the 14.8 volt would work for a 12-volt system. The 11.1 volt would give exactly 12 volts at a certain stage in its cyle; the 14.8 volt would do the same at a later stage in its cycle. The 11.1 would fall off toward the end, and might get too low at a certain point to be effective. At full charge, the 14.8-volt battery pack would start out at about 16.8 (4 X 4.2) volts, which might be too high for some 12-volt devices or systems. But the chargers let you control the high end voltage, so you wouldn't have to charge it that high.

It might be worth checking to find out the usual range of voltages found in automobile cigarette lighters. I'm thinking it might be pretty wide, depending on the state of charge of the (often lead acid) car battery, the alternator, and other conditions. If anyone has more on any of this, or related issues, please post.

There are fast chargers made for AA and AAA cells. The instructions say to usually use the slow charge mode for longer battery life, but faster is available. I've used the Maha Powerex.

I used a solar charger quite a bit. 6V (nominal) with USB out. It would charge a Kindle in about the same time as a wall outlet (ie pretty slowly). I could charge it wth the USB cable that came with the Kindle. Same with cell phone.

There is a great little device, Lenmar PPU as I recall, that I got from Amazon. It is superlight. You do have to take care of it in the sense of no rough handling. It allows you to charge all kinds of batteries from the solar charger's USB port, including camera batteries and 18650s (with some tweaking). I believe ultralighters call these devices 'cottonpickers,' and I believe there are some other models as well.

Long story short: it all worked for about a summer. It was okay. Slow. Rather inconvenient. Not great. It worked though, I'll definitely give it that.

Then it got fritzy and slowly futzed out.

Next time I might try the Suntactics solar panel, if I go that way again. It looks like one of the best. Don't know the expected service life, but it looks good for its type of panel.

I'm more interested in this fastcharging approach for now. I like it.

I'm looking to be able to charge a variety of things -- lithium rechargeable 14500s and 18650s, along with a Kindle and the batteries in a digital camera. Maybe a laptop at times, and maybe cell phones at times. Also NiMH AAs (which I really appreciate -- some of the Sanyos are good for many hundreds of cycles. Super reliable. Lots of power. Great, great batteries).

I do have a Duracell CEF NiMH charger that has a USB-out port (great feature of this charger -- see N Lee's review at www.amazon.com ). Actually two, US and Australian.

The charging isn't terribly snappy but the USB port is very nice to have in such a device, as is the ability to use Sanyo NiMH AAs (which are the great batteries mentioned above that I like and trust).

Ditto for the Xtar WP2II -- same USB-out idea, but it works with lithiums rather than NiMHs. Power transfer to the USB port is not efficient, but it works. I have one and I've used it a lot.

None of this gives fastcharging capabilities, though.

That's what I'm most interested in developing at this point.

Thanks. Good points. I'm leaning toward 11.1 but still wondering about 14.8 too.

Max charging rate for standard rechargeable AAs and 18650s is usually said to be about 1C. Most people favor charging at .5C or lower to extend battery life. Some NiMH AAs seem to do okay at 1C, but many 'fry' quickly and stop holding a charge for long.

A trick that seems to solve this is to charge a set of them together in parallel so they can accept a much higher current. And to charge them to maybe 70-80% so they can accept more current. You can store the juice (the mAh's) quickly this way, which is the main objective.

Or just use those battery packs that are designed to handle the faster charge rates.

I believe ten-minute fastcharging is not unreasonable, with these batteries. Apparently the cycle life declines as charging rates get faster. I don't know the numbers though. It would be very interesting to see a graph.

My sense of it at this point is that some of these packs will last pretty well at ten- or fifteen-minute charging rates. Would like to find out more about this.

Apparently there are cheap Chinese packs that don't last long at all, and others that are much better. Need to learn more about this aspect.

All I know for sure is that some of these batteries work fine for some of the RC guys, and that they often use fast charge rates. That seems like good evidence that this can be made to work. It's just a matter of getting the details right.

Thanks. I'll check it out. Sometimes it's just better not having to wait for hours.

Why not buy a 15 minute charger? In 30 minutes, you'll have enough batteries for a week.

https://www.northerntool.com/shop/too...FUXf4Aodai0A0Q

Anytime a USB port is involved charging will be limited to 500 milliamps. For example, a car charger for a cell phone will often charge noticeably faster than a USB cord will as it isn't limited to just 500 milliamps.

There are quick (~2 hours) chargers and super-quick (<30 min) chargers too for AA, AAA etc. I wouldn't use the super quick ones. If you use a quick charger, make sure it is a "smart" charger that will monitor the battery state and turn itself off once charging is finished.

One of the problems with fast chargers is the heat produced by charging faster. This decreases how many discharges a battery has and these batteries also discharge faster. I have several sets of the AA/AAA Energizer brand fast charge batteries. They have worked pretty well but they also will be completely dead in a month or two with no use. That's not as big of an issue on a bike tour though.

I think a solar charger would work for most that didn't want to go the dynamo route. You charge the solar cell during the day while riding and then trickle charge your device(s) at night. I think there are also USB chargers that use AA batteries as the source. You could get 6-8 15 minute AA's and use those to charge cellphones, tablets and other proprietary batteries at night while you didn't have access to a power source.

I've been using Maha Imedion AA cells because they don't discharge when not in use, unlike most rechargeables. Thomas Distributing.

That's the answer to a different question. Similarly I use Eneloops.

However the question is how to charge faster. My Eneloops take 8+ hours i think to recharge. You can get faster charging batteries like the 15-20 min ones but the downside is that they discharge over time and they have a shorter life span due to the heat generated by the faster charging time. They still work reasonably well especially if you are using them daily while touring.

For NiMH AA and AAA, I am quite happy with the Accupower IQ-328.

It can take both USA and European voltages. Charging rate can be set for fast or slow. Can charge an odd number of batteries which is nice, some of my lights use three AAA cells. Many AA/AAA chargers can only charge an even number of batteries, if you try to charge two batteries that are not equally discharged, it can be problematic.

For travel for compactness and lighter weight I prefer a battery charger that does not have a separate transformer unit. Thus for travel I would not use the Accupower, the transformer unit is quite heavy. But for home use, the Accupower is great. I bought it on Amazon.

More info here.
https://www.accupower.at/media/accupo...nual_iq328.pdf

For Li Ion, I have no recommendations.

So part of the answer probably depends a lot on how many batteries you need to charge and what kind of voltage you're looking at.

For example, I have a battery pack that uses 10 x 2100mAh Imedion AA batteries. By using 3 seperate MAHA chargers simultaneously at a 1A charge rate - I'm done in 2 hours. OK for the house but not exactly a collection I'd like to take touring. The chargers are, combined, 10x the size of the battery pack. Using a single portable charger on the road would take me about 10 hours to do the same thing. Less time with a fast charger, but better have spare batteries as a backup, because those are hard on batteries.

On the other hand a 6,600mAh 3S1P Lipo pack with a 4C charge rating will take a 26.4A charge rate and can be safely charged in about 15 minutes. Again - the chager is larger than the battery, but much more compact than three MAHA's. Alternatively a 2A charger is half the size of the battery and can simply be used to top up the battery when convenient rather than waiting till its absolutely necessary. Thats what I'd travel with.

The extra battery capacity makes emergency charging less likely so a larger battery and smaller charger works out better for me on the road. It's still not much bigger than an iPhone.

So, It seems a trade off : faster the charge rate, the sooner that you have to buy new batteries .

I fly rc airplanes and I use 11.1 lipo packs and lipo chargers when fully charged a 11.1 volt lipo is 12.4 volts and they weigh on grams so you could buy you a cheap head tube pack off ebay an put them in parallel lets say you get 11.1 2200 mah packs and ran in parallel you would have 11.1 4400 mah enough to hook up to a 12v receptical and probally charge a cell phone or a lap top up for a week

Yes, but what if they only last you twenty-six years instead of thirty years?

(Some of the Sanyo batteries that I like are rated for up to 1500 charge cycles. So at an average of fifty charges per year, they would be good for thirty years. Actually, they would still be good after that for quite a while longer; but the capacity would have reached about 80% IIRC at 1500 charges.)

So, I suppose some people would not be living long enough to have to buy new batteries anyway.

There is also the question of acceptable losses.

If you lose 10%, but are able to fastcharge, then some of us (me included) would simply go ahead with the tradeoff and the fastcharging.

Problem is, I haven't yet been able to find graphs or other data to gauge the % losses under various conditions or fastcharge rates.

There may be losses, but they may be fairly minor.

Someone at candlepowerforums has apparently charged Sanyo Eneloops at a fast (one hour) charge rate to see how many cycles they would go through and still be good. As I understand it, the batteries were still going strong after 200 cycles. (If anyone finds this thread at CPF, please post; so far I have only heard about the results; haven't read the thread itself yet.)

I'm thinking of taking a few different types of batteries, and simply "sacrificing" one of each type to an experiment(s), to see how long they will last with a certain 15-minute charger, for example. It seems that some batteries can take faster charge rates much better than others (I already experienced that with a 1-hour charger and different batteries used in it).

Maybe repeat for a 30-minute charger.

I think these Sanyos will be okay with 1-hour charging (assuming my charger is not harder on them than the charger on the CPF thread).

The Sanyo Eneloop XX (high capacity Eneloops) may fare better, or may fare worse.

For 30-minute and 15-minute charging, I haven't yet found much good data.

This territory -- some of it at least -- is probably best navigated by direct personal testing with one's own equipment.

Great to hear about this.

This is another direction I want to explore.

(Both this and the AAs.)

Does anyone have any recommendations for good chargers and lipo packs?

These are unusual for their ability to serve as battery banks with AAs:

(providing AA-powered USB out)


https://www.amazon.com/Duracell-Charg...ll+cef+charger

https://www.amazon.com/Duracell-Charg...ll+cef+charger

Something to keep in mind is that every battery chemistry has a shelf life. The life of the battery is determined by the number of charge cycles OR the shelf life - whichever comes first. No battery on the market I'm aware of has a 30 year shelf life. Three years is pretty much the norm for most consumer grade lithium batteries.