I need some schooling on batteries….

in our world, rechargeable will always have less overall capacity than the best lithiums. on the other hand, lilion's are the devil to properly test, so you pretty much "need new" every time, for mission-critical use.
in the realm of AAA and AA batts in alkaline, they are dead easy to test, and have a good fraction of the lilion capacity. along with more weight. and they are Cheap (which, that be good too). but perhaps not quite so great in colder places use, but since they all substantially cold fade, ymmv.

peter has had entirely perfect service from the everyready top end lilion AAA batts. zero failures. i just keep buying them, and they just keep working.

this does nada to answer your exact query. i know that.
sorry luv …

cheers,
v.

18650 is a size. Approximately 18 mm diameter, 65.0 mm long. The same sizing is used for coin cells, e.g. CR2032 is 20 mm diameter, 3.2 mm thick. "18650" with no qualifiers is typically a Li-ion, not a NiMH cell, so ~3.6 V instead of ~1.2 V.

18650 is a very common size to build battery packs out of, such as those for electric drills, laptops, garden tools, etc. The ones in those packs do not have a "bump" on the positive end, though. Rather, they have tabs tack-welded to both ends for convenient soldering into batteries without overheating the cell.

I have several flashlights that take 18650. Once you "buy into" the system with a couple of cells and a charger, it's very nice to have such a lot of capacity in a single cell that can be quickly changed. The energy storage is about equivalent to four or five Eneloop AAs. I don't know that there's any energy/weight advantage, just less fiddle factor.

Eneloops, or anything labeled "precharged NiMH" have a low self-discharge rate, typically advertised as retaining 85% of their charge after a year. Older/standard NiMH, on the other hand, lose about 4% per day, so you'd be at 85% after a week. However, they typically have a higher capacity when fully charged, around 20% more.

Hi Jennifer,

Per Delorme's FAQ page:

"The battery in the inReach SE is a 2,450 mAh capacity at 3.7 V. The inReach SE has been tested to last 100 hours, based on transmitting one track point every 10 minutes with a clear view of the sky."

I've never had my hands on one but is it safe to assume that it can be charged with a USB or micro USB cable? If so, you can buy one of the hundreds of battery banks available on the market. I bought a cheap one from Fred Meyers and it works fine.

Assuming you'll want to charge it once per week in the field and that you'll have a zero/nero once per week to plug your Delorme and battery bank in, allowing for 30% loss during transfer, you could get by with a battery bank with at least 3,185 mAh. Just make sure you get one with the right voltage which in this case is 3.7. Not sure if a 5V battery bank will work or not so I'll let someone techier than me answer that.

Thanks guys….this is the kind of stuff I'm looking for.

It's fun to read about the 18650 ones, and Eneloop…but when folks talk about it, they talk about it with people who understand the lingo. So thanks for the primer!

Now I can research with a bit more background. You guys rock! As always…….

Love me some nerds!!!!!!
(from a fellow nerd, by the way…..in case that wasn't clear…..)

Flashlight forums like the Candlepower Forums or the Budget Light Forum are good places to find information ans reviews about 18650s. As Andy said, they are very energy dense. They also can support ridiculously high draw amounts. This is one of the reasons you see them so often used in high performance flashlights. One consideration about any of the 3.6/3.7v rechargeable cells is a good charger. An improper charging circuit at best can reduce the life of the cell (recharge cycles), at worst could cause a fire. Your choice of charger is key. Fortunately there are some good resources for 18650 charger reviews.
This guy is really thorough:
http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.html

Jennifer, I'm a recovering flashaholic, so got rather deep into battery performance a year back. My comments here are not Delorme specific, but general. Mostly targeted at AA and AAA cells, but may furnish some background info.

Loooong story short, I settled on Eneloops (which are NiMH chemistry) in most my AA devices for several reasons: 1) they're safe 2) they don't leak in gear 3) they're easy to recharge 4) they hold charge a good long time 5) they're inexpensive 6) they can dump a lot of energy when they're called upon to do so. But to use these batteries well, one needs a good charger that can every once in awhile refresh the batteries. I use the Maha C-9000, an often recommended charger.

That said, for short backpacking trips (ie, no recharging needed), my Eneloops get laid aside in favor of AA lithium primaries (the NON-rechargeable lithium cells you buy off the shelf in stores) because of their 1) light weight 2) very excellent power.

I explored the rechargeable lithium route briefly (18650s) and on my first attempt, got an overheating cell. That soured me on the experience and I backed out, decided I'd live with lower performance for increased safety. Now there are scads of people who recharge li-ion successfully so I'm definitely an outlier there. My thinking was I'd be using 18650s for headlamps, and given the $$ I've spent on education, I decided I just didn't need that much power <1" from my brain. Again, loads of people use Li-ion on their headlamps with zero problems, so just a personal call.

You don't wear your Delorme on your head, so…probably not an issue for you.

The area you want to be careful with rechargeable li-ions (well, all cells, but be especially cautious with rechargeable li-ions) is a multi-cell device, where you mistakenly insert a depleted or nonfunctional cell, and other full-charge cell(s). That's the sort of situation where the fireworks can happen, when the full cell(s) tries to charge the dead cell. Not good.

Whatever cell chemistry you use, and particularly in multi-cell devices, be certain to learn how to check charge in all your cells and try to match cells for capacity. (A good charger like the Maha for NiMH makes this easy.)

One simple test. This is not complete, but it is better than nothing.

When you get a new battery system, and when you first start using the new batteries, periodically feel the outside of the batteries or the outside of the battery case that they are mounted within. Get a feeling for any normal temperature. Then later, if something goes wrong, there might be some severe overheating, and you might feel it before it totally explodes or ruins the headlamp. With lots of battery types, during charging there is a normal and small amount of heat given off, and you want to be familiar with that. Lots of batteries will have a longer life if they are charged at a slower rate so that they never get warm. On the other hand, in order to pump the maximum amount of charge into a battery, you have to push it until it is warm or else very warm.

–B.G.–

I've gone with the 18650 chargers because as others have mentioned, the energy density of the 18650 batteries is very good. I used Lithium disposable cells in an AA charge for a few years but they are expensive and a partially charged disposable cell is useless to me because I will always buy a fresh cell before a trip. Rechargeable Lithiums (in my case 18650's) are a blend of performance and economy.

There are also some very good power supplies that have built in batteries but I want to be able to take extra batteries based on the length of my trip, so I'm not interested in self contained battery banks. I also have a headlamp that takes 18650 cells so having a battery bank with an 18650 serves dual purposes (I can use the battery bank battery in my headlamp if needed).

I have two battery bank/chargers, the Miller ML-102 and the eNB 1A 1/2.

The Miller charger "must" use 18650 unprotected "flat top" cells. These batteries are unprotected cells which means they are capable of being over charged (could catch fire) or over discharged (may never charge again). A good charger/battery bank like the Miller charger shown below prevents the batteries from being over charged or over discharged, so not really a concern. The unprotected cells are required in the Miller charger because they are slightly shorter than the protected cells (protected cells won't fit in the Miller charger).

Miller battery bank/charger ($5.96):

18650 (3400 mAh) flat top unprotected cells ($15.68):

I also have the eNB charger which uses 1 or 2 18650 cells. The eNB charger can use either protected or unprotected 18650 cells. I really like the LED battery level and charging status indicator on this charger. The light flashes while charging and will turn off once your device is fully charged (with the Miller charger it's difficult to tell when your device is fully charged if the device being charged is turned off). The eNB battery bank can use either one or two 18650's as a power source.

eNB 1A battery bank/charger ($9.40):

18650 (3400 mAh) button top protected cells ($17.35):

Both of these chargers/battery banks have built in circuitry to protect the cells from catching fire from over-charging or from being completely depleted when in battery bank mode.

I use the following cable for charging my iPhone and inReach (my camera is a custom mini usb so I have to carry that as well).

Combination cable for iPhone and inreach ($1.41):

As for output, the Miller charger will charge my iPhone two full charges (on a single 18650) and the eNB 1A charger will charge my iPhone 4 times with 2 18650 cells in the unit. Both chargers brought my iPhone from under 20% to 100%.

I can charge my inReach one full charge with the Miller battery bank with one 18650 battery (went from 12% to 94%). I haven't tested the eNB 1A with my inReach but I'd expect to get two full charges with it if I load it with two 18650's.

“… I am in the market for some sort of recharging device for my Delorme,.. I see 18650 written quite a bit….what kinds of batteries are these and why are they good for recharging devices?”

They’re very good for recharging devices. The Delorme I looked at has a 2450mAHr battery. This is the same as my wife’s Note 1 phone. We keep an 18650 style charger (from Anker) in her purse. This charger can do one full Note 1 recharge. And the Anker can hold a charge for several weeks.

Now if the Delorme has a 5V connector for charging most likely this Anker device will work. http://www.amazon.com/gp/product/B00EET7UHE/

I haven’t taken NiMh batteries for a while backpacking since that’s the heaviest option. I do use AA lithiums a lot backpacking. That’s the lightest option (when considering energy density).

If you buy a AA cell recharger for the Delorme, I would suspect alkalines won’t work very well (die fast). The lithiums and NiMh should work very well since they have the lowest internal resistance.

And some more useless info: The Tesla electric cars use between 5000 to 7000 of these 18650s; high performance!

Let us know what works for you,

-Barry
-Loving my lithium powered vehicle, the iMiev http://www.mitsubishicars.com/

Hi Mike,

If you don't mind, I have a couple questions about your system. Probably due to my crappy google-fu but I found ENB but I didn't find that exact charger. The ones I found indicated that their output is rated at 5V at 1.5A.

Since my knowledge of things that go zap can fill a thimble, this is where I go off a cliff but here's my faulty logic…

A single 18650 is 3.7V so it would seem to me that if the charger ran them in series, it should be delivering 7.4V but only 3400 mAh (since it'd be in series) but since it's a battery bank, it's all about mAh so theoretically the two 18650 batteries rated at 3400 mAh would likely supply 6800 mAh in parallel at 3.7V leaving me to wonder where the 5V is coming from so some sort of voltage converter in the circuitry maybe? But then you mention that while this charger can hold two batteries, it will operate with just one so then if you only had one battery in there, it will deliver 3.7v (rated input for Delorme) and make this a non-issue?

At any rate, my limited understanding is that a surplus of amperage is basically a non-issue as the receiving device will only draw so much but a higher voltage may become problematic. This becomes obvious when you plug a 110v into a 220v socket but not so sure when comparing 3.7v to 5v and maybe it's close enough to allow for some Kentucky windage?

Sorry as I realize I'm throwing a lot at you (and I should probably take this question to Radio Shack HQ) but it sounds like you know what you're talking about so I thought I'd take a chance.

Also, since this is BPL, regarding energy density per gram, how much do your batteries and chargers weigh?

"A single 18650 is 3.7V so it would seem to me that if the charger ran them in series, it should be delivering 7.4V but only 3400 mAh (since it'd be in series) but since it's a battery bank, it's all about mAh so theoretically the two 18650 batteries rated at 3400 mAh would likely supply 6800 mAh in parallel at 3.7V leaving me to wonder where the 5V is coming from so some sort of voltage converter in the circuitry maybe?"

If one battery is rated at 3.7V and 3400 mAH, then two batteries in series will give you about 7.4V and 3400 mAH. That should be plenty to charge a third battery that wants to see 5V.

What is all of this "it's all about mAH" crap?

–B.G.–

"What is all of this "it's all about mAH" crap?"

(Taking a deep breath, looking at the nice weather outside, and grasping my climbing permit like a talisman to ward off bad karma)

Bob, I live near Hanford and can't swing a dead cat over my head without hitting an anal retentive engineer. Come at me bro! I can take it! :)

The battery banks I own or have worked with allow for the user to select voltage and/or amperage delivered. Yes true, if someone needs 5V to charge their gadget and a single battery only delivers 3.7 then it's not "all about mAh" and you'll need a second battery run in series to get the higher voltage or presumably some kind of voltage converter/transformer/whatever if that's even possible as I've only stepped voltage down this way, not up.

For ME, I'm looking to store the largest amount of mAh for the lightest weight that will cover my needs delivered at the correct voltage and amperage. This device may do all that but all I can see is an on/off button, I don't have the instruction manual, and I didn't see information about this on their website.

For the OP, her gadget's rated input is 3.7V so just trying to clarify if 5V is close enough for government work or would potentially damage her gadget.

"For the OP, her gadget's rated input is 3.7V so just trying to clarify if 5V is close enough for government work or would potentially damage her gadget."

No, you won't get a 3.7V battery to charge up a 5V battery unless there is another power converter in between to get the 3.7 up higher than 5, and that power converter would demand even more amperage and drop some efficiency in the process.

–B.G.–

It's tough to beat an 18650 for a battery pack device. They hold a lot of juice for little weight and can be very inexpensive. There are 26650 and 32650 batteries which are enormous in comparison, but the power to weight ratio isn't there(yet). I use a fairly similar set up to Mike above.

Orbtronic 3400maH 18650's

HuanGao Battery Pack/Charger – 40g.

Ryan

Thought I wasn't too interested in this thread, but now my interest is tweaked, and I have a question. Is the focus here on the removable/modular batteries for charging simply so you can bring more batteries for longer trips, or less for shorter ones? Would a dedicated (hopefully optimized) USB battery provide more mAh per oz? For example I have this one (4.4 oz):

http://www.amazon.com/gp/product/B00EF1OGOG/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

or is there a savings in mAh/oz as well? It depends on the efficiency of the batteries so not a clear answer from superficial numbers. I would assume the efficiently of an integrated device would be greater, though more expensive. Is it totally clear that charging your batteries with the big battery is less mAh/oz efficient than carrying more batteries?

Of course the point is moot if you can make it between wall charges on one set of batteries.

For poops and giggles, I dug out my cheapie battery bank and think it's fairly comparable to a single 18650 battery and charger. It has 3600 mAh and can charge a device at 5V 1A, 5V 2A, and 9V 1A.

It weighs 4oz and obviously has a built in charger. I'm not familiar with the state of the market to say if this is good or bad.

Any 18650 owner care to weigh a single battery with its charger for comparison?

With some lazy googling, it seems like the availability of battery banks which can charge at 5V is much higher than those that can charge at 3.7V (what the Delorme requires). Of note, one mentioned that it is 5V max so I'm starting to think that I'm probably over-thinking it and 5V is fine.

Edit: speculation is worthless so I sent them an email asking for clarification. I may pull the trigger on one later this year so admittedly I have some selfish motives.

Edity edit: just read through the parallel thread on Delorme and it seems that others are charing it fine at 5V.

Panasonic (formerly made by Sanyo) Eneloops would not be a first choice for a battery bank charging system, but they are a number one choice for most electronics that take AA or AAA batteries. They keep increasing their performance, I'll try to quote the latest specs.

Long shelf life: 85% charge after 3 years 70% after 5 years. Which also means you can use them immediately after purchase without having to charge first. Factory charged via solar. Great for low use items like remote controls, or that kitchen drawer flashlight. Standards are completely dead in a year or two, some even less.

Good for high energy devices. Allows for fast current draw of electronics like camera flashes and makes them a favorite for the really high output flashlights. Standards, and even alkalines sometimes, can balk when a high energy drain is called for. The AA Zebralights for example, specifically recommend only lithium or eneloops due to the high tax placed on the battery.

Good in cold weather: Works better in freezing temps compared to standards. Rated to -4 F, but I kind of wonder about that.

Superior cycle life: The latest models claim they are good for 2,100 recharge cycles. You could recharge one battery every single day, and it would last over 5 1/2 years before dying. Swap it out for a charged one and a pair would last 11 years. Spendy to buy, but very cheap to use. Much more green than lithium for short or weekend outings.

>> Hi Mike,
If you don't mind, I have a couple questions about your system. Probably due to my crappy google-fu but I found ENB but I didn't find that exact charger. The ones I found indicated that their output is rated at 5V at 1.5A. <<

First off I should have mentioned that everything I have purchased recently (Miller battery bank, 18650 batteries and eNB battery bank were purchased at http://www.fasttech.com/ — thanks to another BPL member for putting me on to that store… geek heaven!)

I'll try to clear up a few questions with my limited knowledge of batteries. The 18650 batteries that I have purchased are 3.7 V and 3400 mAh. The Miller and eNB battery bank/chargers list an output and input voltage of 5V. That's because the input and output is USB and USB is 5V.

USB amperage is all over the place depending on the source (ie. old USB is lower amperage and wall charger USB tends to be higher amperage). The battery banks I mentioned put out a pretty good amperage (1 amp for eNB and 1.2 amp for the Miller) which means your devices will charge pretty quickly (lower amps = slower charge time).

The fact that the 18650 batteries are 3.6 Volt (mine actually measure at 4.25 V), means that the Miller and eNB power supplies must boost the output voltage to 5V (to be equal to USB). As Bob mentioned, bumping up the voltage uses up some of the batteries power and the Miller lists it's charging efficiency at 85%. Which isn't too bad.

So now for the numbers:

iPhone 4 battery = 1420 mAh
inReach battery = 2450 mAh

18650 battery = 3400 mAh X .85 = 2890 mAh (reduced by 85% because of the Voltage boost required for USB output voltage)

Which as you can see, agrees with my bench tests:
inReach can get one full charge out of one 18650
iPhone can get 2 full charges out of one 18650

Note: the eNB charger connects the batteries in parallel so the output Voltage is not doubled. There wouldn't be any point in wiring the batteries in series because the output has to be USB voltage (5 Volts), so putting the batteries in series would mean they'd have to reduce the voltage down to 5V (again, inefficient).

I hope this helps.

Ian,

One of my 18650s is 45g, and my charger is 40g. So right at 3oz combined.

Ryan

This is why I joined BPL!

"Note: the eNB charger connects the batteries in parallel so the output Voltage is not doubled. There wouldn't be any point in wiring the batteries in series because the output has to be USB voltage (5 Volts), so putting the batteries in series would mean they'd have to reduce the voltage down to 5V (again, inefficient)."

Tremendously helpful! I realize that a 12V car battery will operate above 14V but I was (obviously) confused between the discrepancy between 3.7V of the 18650 battery (and Delorme Inreach) and 5V rated output of the charger. As I suspected, I was overthinking it. I realize that 220V and 110V are miles apart (as witnessed by a number of GIs cooking their stereos, alarm clocks, etc in Germany) but it seems the 3.6V through 5V are within operating limits.

"I hope this helps."

You have no idea!

Ryan,

Thanks for posting the weights. Sounds like you get more mAh bang for your buck than I do.

All,

It's been some weeks since I've read the other Delorme thread started by Rex and didn't realize until last night how much of this was covered over there. Great stuff! To be honest, this battery and compatible gadgets like the Zebra Light H602w 18650 XM-L2 Flood weren't on my radar before but I see that I need to crunch the numbers to see if this will make sense for me in the future.

Just some simple electronics here that I know may be obvious to many, but all but the simplest devices should have built-in voltage regulation at the source, so within reason (depends on the voltage regulator chip used) you can input a range of voltages and the voltage regulator will insure the voltage on the other side is a steady 3.7V (or whatever is required). Should have current regulation too. Voltage and current regulator chips cost pennies, especially when bought in bulk, so it is safe to assume they are there most of the time. If the charging cord attaches via a mini usb, and especially if it has an option to plug it into a computer usb to charge, then is it probably safe to assume you can input a range of voltage around 5V without issue. On the other hand that range might not be in the idiotic stuff they tend to provide with the product.

"(mine actually measure at 4.25 V)"

Mike, the 3.7v figure is the nominal voltage. This is the voltage that the batteries come with in their "uncharged" state basically. With lithium cells, it's really important not to discharge the cell past this point. A lot of 18650s have protection circuits to prevent this (as well as over-charging).
The ~4.2v figure is the acceptable voltage for terminating the charging of the cell.

As for a boost circuit to turn an 18650 into a constant 5v USB power supply. They are dirt cheap. I made my own USB power bank with an 18650 and one of these circuits I bought off of eBay from a HongKong vendor for about $4. I can find a link if someone is interested. All it takes is two wires soldered from the circuit board to an 18650 holder.

All modern rechargeable electronic devices use lithium ion batteries. They come in many many different chemistries and sizes. If you run higher voltage you need less amps. If you need less amps per battery, you can increase the capacity which lowers the draw limit. This is why there are many different chemistries. For example, an 18500 can have a safe draw limit of 50 amps, however its capacity will be limited to 1100mah. Another 18500 with different chemistry could have a 10 amp draw limit, but a capacity of 2000mah.

These chemistries and sizes dictate the capacity, safe draw limit, and safe charge limit.

If you bust open laptop batteries you will find cylinders of these batteries all linked together into a battery pack.

Only a few factories in the world make batteries, most are rebranded and repackaged from just a few roots.

Look into 22mm batteries, 18mm batteries, 26mm batteries, hobby batteries, etc etc etc. The list goes on forever.

Panasonic makes some pretty nice lithium ion batteries IMO. They currently have a 2000mah 18500 that is the bee's knee's as well as a 3400mah 18650.

To complicate this issue further. Some batteries are electronically protected, while others are not and rely on the components of the device to offer protection. Using a protected or unprotected cell is very important and you should always use what the electronic device calls for or it can be damaged. For example, a digital device with its own protection circuit will not get along well with a protected li ion cell.

If you run a lithium ion cell too low, it will "vent" which is a sort of explosion. Devices that use high drain lithium ion cells either require protected cells or have internal protective circuits combined with vents to prevent an explosion of the device in the event the cell fails and vents. It is not a powerful explosion when a cell "vents", more or less similar to fireworks. It can do damage but its not going to cause MAJOR damage.

When my 12 cell lithion ion (3.7v x 12) fails, yes it goes up in flames. When my single cells fail… they don't really do much other than make smoke. I've seen a few 50 amp high drain cells spin on the ground like fireworks and leave a nice scorch mark though.

Safe chemistry lithium ion cells are nothing to be afraid of though, FYI, which is the majority of what we use in our devices.

Goodness I love nerds. I so feel like I've found my people, my home.

Thank you.