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I need some schooling on batteries....
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Ian B.
(IDBLOOM) - MLife

Locale: PNW
Re: I need some schooling on batteries.... on 05/09/2014 09:16:17 MDT Print View

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.

Edited by IDBLOOM on 05/09/2014 09:30:53 MDT.

Marko Botsaris
(millonas) - F - MLife

Locale: Santa Cruz Mountains, CA
Re: Re on 05/09/2014 10:11:51 MDT Print View

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.

Edited by millonas on 05/09/2014 10:16:08 MDT.

Benjamin Meadors
(thebentern) - F

Locale: Central Arkansas
Nominal voltage on 05/09/2014 11:01:43 MDT Print View

"(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.

Edited by thebentern on 05/09/2014 11:03:17 MDT.

Troy Childs
(tchilds) - F
Re: I need some schooling on batteries.... on 05/09/2014 21:09:49 MDT Print View

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.

Edited by tchilds on 05/09/2014 21:26:02 MDT.

Jennifer Mitol
(Jenmitol) - M

Locale: In my dreams....
Re: Re: I need some schooling on batteries.... on 05/10/2014 07:33:43 MDT Print View

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

Thank you.

Ian B.
(IDBLOOM) - MLife

Locale: PNW
Response from Delorme on 05/13/2014 08:57:54 MDT Print View

I think the question was already answered here but here's what Delorme had to say...

"Hello Ian,

Thank you for contacting DeLorme Technical Support. This inReach can withstand a 5V charge at 1A with no problem. Please let me know if you have any further questions. Have a great day!

Regards,

Casey A
DeLorme Customer Care
Phone: (800) 511-2459 or Internationally at (207) 847-1165
Many answers can be found at our on-line knowledge base within the link below.
http://support.delorme.com"

Jim Milstein
(JimSubzero) - M

Locale: New Uraniborg CO
Voltage Regulation on 07/17/2014 20:51:20 MDT Print View

Since there is some confusion on the topic of voltage, I am going to make it worse.

Most of the rechargeable Li-ion cells are nominally 3.7V. Their safe range, from fully charged to a safe discharge level is about 4.2V to 3.2V. Some devices may run them lower than 3.2V, but not much.

However, devices that are recharged through USB cables, typically with a micro-B plug, expect 5V. Rechargers powered with Li-ion cells that accept USB cables will provide about 5V. How do they do this? Little bitty solid-state circuits that take whatever the cells are giving and convert it into what the USB specs require.

As mentioned in an earlier post, the cost of this service is a loss of efficiency, perhaps 15%. A similar thing happens in the device being recharged. Its cell(s) (Li-ion) need various voltages at different times while charging, and those are supplied in the device by its own circuitry, starting from the standard USB 5V input. All this voltage regulation is done with solid-state magic -- no transformers allowed. Remember those big heavy wall-wart or brick power supplies of old? Transformers! In modern low-power devices transformers are as obsolete as vacuum tubes.

Some people have never even seen a vacuum tube. Well, actually they have: That's what TV tubes are, but now many kids are growing up ignorant of display history. Kids, these days!

Mark S
(gixer) - F
watts not voltage on 07/20/2014 12:52:07 MDT Print View

When thinking about charging it's better to use watts rather than voltage, as this is really the measurement we are really interested in.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: voltage not watts on 07/20/2014 13:54:50 MDT Print View

You can think about the watts all day if you wish, but if the input power source voltage is less than the rechargeable battery voltage, you are never going to accomplish anything.

Getting that extra little bit of driving voltage can be very handy. Take a lithium primary AA battery voltage, typically around 1.7 volts. Three of those in series gets you around 5.1 volts, and that is a good voltage to use to recharge a rechargeable lithium ion battery. In contrast, if you tried to use three rechargeable AA batteries in series, it would likely work for only a moment and then stop.

--B.G.--

Edited by --B.G.-- on 07/20/2014 13:55:22 MDT.

Jim Milstein
(JimSubzero) - M

Locale: New Uraniborg CO
Re: watts not voltage, or rather Wh on 07/20/2014 14:14:22 MDT Print View

I think you mean Watt-hour, Mark, which is an amount of energy. A Watt is a rate of energy.

For the small rechargeable Li cells we've been talking about, multiply the nominal voltage (usually 3.7 V) by its mAh rating (e.g., 2450 mAh) to get its mWh capacity (9065 mWh), or divide that by 1000 for the Watt-hour value (9.1 Wh). If a device consumes 90mW on average, then it will use 9.1Wh in 100.7 hours. The cell in this example might last 101 hours powering the device, plus or minus, depending on several variables.

Jim Milstein
(JimSubzero) - M

Locale: New Uraniborg CO
Re: Re: voltage not watts on 07/20/2014 14:20:16 MDT Print View

"You can think about the watts all day if you wish, but if the input power source voltage is less than the rechargeable battery voltage, you are never going to accomplish anything."

Bob, do not ignore the role of solid-state voltage regulation in virtually all chargers these days. I discussed this a few comments back.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: voltage not watts on 07/20/2014 15:15:18 MDT Print View

Jim, I understand the purpose of a voltage up-verter. However, if you are using plain lithium batteries in series, you skip the up-verter and the efficiency loss, and you can just drive the rechargeable battery directly. That's what I have.

--B.G.--

Mark S
(gixer) - F
Re: Re: voltage not watts on 07/20/2014 16:12:28 MDT Print View

"You can think about the watts all day if you wish, but if the input power source voltage is less than the rechargeable battery voltage, you are never going to accomplish anything."

And yet the setup i've been using daily for the last 2 years DOES work and works very very well
 photo 20140524_200103_zpsj19zn6ct.jpg

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: voltage not watts on 07/20/2014 17:18:52 MDT Print View

"And yet the setup i've been using daily for the last 2 years DOES work and works very very well"

What you show says nothing at all about voltage or watts or watt-hours or anything else, except that maybe it weighs 213 grams.

--B.G.--

Jim Milstein
(JimSubzero) - M

Locale: New Uraniborg CO
Re: Re: Re: Re: voltage not watts on 07/20/2014 17:58:03 MDT Print View

Bob, you asked for it by implying that if the cells don't supply enough voltage to charge something then FAIL. The photo shows a Miller ML105, which bumps up the 3.7 V of the 18650 in it to 5 V output. You know all about this, but you are just being ornery.

Your scheme, Bob, of directly producing the five volts is fine so far as it goes, but the drawback is that when the Li cells' voltage starts to drop, the remaining capacity of the cells is no longer accessible, though admittedly that's not a lot. The Miller charger sucks just about all of the useful charge out of its 18650 -- but with some loss of efficiency (probably about 15%).

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Re: Re: voltage not watts on 07/20/2014 18:03:00 MDT Print View

"Bob, you asked for it by implying that if the cells don't supply enough voltage to charge something then FAIL."

Jim, no I did not. I said nothing and implied nothing about cells at all, did I?

The _source_ has to have enough voltage to drive the rechargeable battery. In this case, what is coming across the cable is likely to be about 5 volts. That is the interface point between the two. The OP did not identify this as being a Miller anything, so it might as well have been a 218-gram rolling pin.

--B.G.--

Mark S
(gixer) - F
Re: Re: Re: Re: voltage not watts on 07/21/2014 04:24:20 MDT Print View

"What you show says nothing at all about voltage or watts or watt-hours or anything else, except that maybe it weighs 213 grams."

Why do i need to show the outputs, Jim clearly stated these devices have a voltage regulator or step up inverter in old currency.

If you don't believe Jim the voltges are clearly stated in the specs
http://www.fasttech.com/product/1137904-miller-ml-102-universal-usb-smart-charger-version

Current Output 1.2 A
Output Type DC 5.1V

Then you have my experience of 2 years pretty much daily use of the device.

Will that voltage converter lose some efficiency, more than likely
Does the device still work well, yes

When hiking i tend to put my phone into airplane mode and use Endomondo as a GPS logger, after a 8 to 10 hour days i've usually have around 30% to 40% battery left in my phone (Galaxy S4).
My phone uses a 2600mAh battery, so at 40% it will have drained around 1500mAh out of it.

The 18650's i use are 3400mAh and i am seeing 2 day and a bit days use out of 1 3400mAh x 18650 cell.

The pic i posted is of 3 x 3400mAh cells that lasted me 7 days of charging my phone and GPS device.