14500 Lithium batteries - same size as AA (nearly)
LoopyByteloose
Posts: 12,537
I went shopping for some generic Lipo batteries for RC electric airplane and discovered the 14500 series that are 3.7V and some are even over 2.4ah capacity. They are 0.5mm longer than regular AA.
I was a bit surprised that I had several options with rather big increases in capacity. I have the 18650s, but mine are 1950ma and now there are 3000ma ones available. And in the 16555, I can get 2700ma.
Since these charge much faster than the NiCd genre, and provide more than triple volt in an AA package - it seems time to permanently set aside Alkaline and NiCd batteries.
I was a bit surprised that I had several options with rather big increases in capacity. I have the 18650s, but mine are 1950ma and now there are 3000ma ones available. And in the 16555, I can get 2700ma.
Since these charge much faster than the NiCd genre, and provide more than triple volt in an AA package - it seems time to permanently set aside Alkaline and NiCd batteries.
Comments
Hmmm...
Until the wife or kids grab 4 without asking and use them in place of AA batteries.
I love the smell of coffee, Christmas trees, and magic smoke in the morning!
An Ebay search shows many rated at 1200 mA: http://www.ebay.com/sch/i.html?_nkw=14500++battery&_sacat=92074&_sop=15&_odkw=14500+Lithium+battery&_osacat=92074&_trksid=p3286.c0.m270.l1313
Hmmm...
Until the wife or kids grab 4 without asking and use them in place of AA batteries and magic smoke ! .....> come out
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I caution you to let other in your house hold that these cell are NOT the same battery that they use to
It seems with the amount of power available and the higher voltage, these guys will begin to seriously overtake the Alkaline cell market. NickelCadium and such never got a good foot hold because they didn't provide as high a voltage and charge was often less.
At least for hobby stuff, I am ready to go all lithium now. Just think, one battery, no regulator can run a Propeller for roughly 10 hours.
http://www.ebay.com/itm/10-x-3-7V-1200mah-14500-AA-Li-ion-Lithium-Rechargeable-Battery-/251068691004?pt=US_Rechargeable_Batteries&hash=item3a74dc323c
http://www.ebay.com/itm/2-Pcs-3-2V-1200mAh-123A-CR123A-16340-LiFePo4-LFP-Rechargeable-battery-Ultracell-/150823210725?pt=US_Rechargeable_Batteries&hash=item231dc38ee5
Rechargeable 2000 times.
Fully charged in 30 minutes,
Can handle very high current peaks.
No heavy-metals.
No explosions
Here is a charging ic: (simple rules to lifepo4 is: never below 2,.2v and never higher than 3.65v)
http://www.mouser.com/ProductDetail/Microchip-Technology/MCP73123-22SI-MF/?qs=E6wAi2XWqcMqq2JIuuGEkYadBjEA7JSociTfMM1zDwg%3d
A full charged Li-Ion is about 4.2V. Do you use a diode between the battery and the Prop?
BTW, I just purchased a set of 10 from erco' eBay link.
Tony, These look interesting.
Have you every used these batteries and the charger?
What's the battery's max voltage?
How would you suggest powering a Prop from it?
One option is to use a tiny bridge rectifier to have two diode drops and to not have to worry about correct polarity at the battery mains.
The fact that lithium batteries charge so quickly is really quite wonderful. NiCads are slow. Lead Acid is slow.
I see my last post was in December and the truth is I have yet to fully explore these. I was thinking of actually powering an R/C airplane with brushless motor, but I've yet to finish building the plane. All the parts are here, I just have to get to it.
Thanks for the sugguestions about a rectifier.
I think one reason LiPos are so popular with R/C aircraft is they lack the metal can of a Li-Ion so weigh less. I also think AA size might not be the best size for R/C aircraft because of the can of the battery is likely a larger percent of its weight than sub-C cells (I'm thinking of surface area vs volume). These should still have a much better energy density than any of the old NiCd packs.
Silly Duane. He took the bait AGAIN.
-- Gordon
There is a lot of information on their site, for example,
LiFePO4 at 120 Wh/kg
LiCoO2 at 200 Wh/kg
Li-poly at 160 Wh/kg
Pb-acid at 35 Wh/kg
NiMH at 80 Wh/kg
I received the Li-Ion cells from erco's ebay source a few weeks ago and today I received these below.:
They look like batteries, but they're not.
They have zero volts across their terminals and very low resistance from one terminal to the other. I think they are just empty metal shells.
One of these "cooloop" cells weigh 4.6g. An "eneloop" AA cell weighs 26.0g.
I think these were sent by the same people selling the Li-Ion cells.
It occurred to me, these could be used with the Li-Ion cells to lower the voltage when using a multi-cell battery holder. If one had a three cell battery holder and used one Li-Ion cell and two "cooloop" cells, then the voltage would be pretty close to what one would get from using three NiMH cells.
Did any of you purchase batteries from the ebay item erco's linked to? If so, did you also received these battery holders with fake shunt cells?
Edit: This was not a rip off. The seller went out of their way to make it possible to use the Li-Ion sells in consumer goods. See erco's post #18 for clarification.
There are some very weird fakes about. Audio electrolytic capacitors that actually have a smaller out of spec capacitor inside the larger's case.
I don't use E-Bay and try to return what I buy over the counter so as to let them know that they are not buying from the right kind of people.
BTW, lithium batteries that have less that the appropriate voltage, do short circuit. Could it be that they just sent you defective batteries?
And, never use a new lithium rechargeable without first charging. If you drive the battery too low, you have destroyed it.
Sure, they may be dummy batteries. But it is still a cheat, isn't it?
Generally, reputable electronic parts retailers use battery sales to bring them repeat customers. Radio Shack has for years. They won't sell bad quality batteries as unhappy customers don't return. It is similar to a camera store selling bad photographic film or a donut shop with lousy coffee.
I read one email from the seller cautioning against using the Li-Ion in consumer goods since the voltage would be too high. They also sent a second email which I assumed said the same thing and I didn't read it.
Now I think the second email was to to tell me these battery spacers where on their way.
These batteries are so light weight, they're obviously hollow inside. I'm sure they're not defective batteries.
I don't follow you. I don't think it's a cheat.
I purchased Li-Ion batteries that are AA size. The ebay page made it clear the voltage of these batteries were too high to use with normal electronics equipment.
I plan to use my batteries in custom projects and I have a lot of AA battery holders so it's easier to me to use AA sized Li-Ion cells than the other sizes.
The seller not only went out of their way to remind me of the danger of using these batteries in normal equipment but went the extra mile and shipped these blank cells so we can better match the correct voltage if we choose to use them with consumer equipment.
Each cell has a "Do Not Charge" warning on it. I also think the battery cases are pretty cool.
I don't see this as a cheat at all. I'd go out of my way to buy from this seller again. They seem very conscientious.
There is no problem.
There is no scam.
There is no conspiracy.
No one is selling empty batteries.
This is a particularly great thing from an unusally responsible Ebay seller, freedom345. The seller from whom Duane and I bought ten (10) 14500 batteries shipped them to us in fine style. No problems. Nice batteries delivered in a timely fashion. That could have been the end of it, all parties happy. Then shortly thereafter, the seller sent this email:
Hi.
Dear buyer, thank you for purchasing our products.
I must remind, because it is 3.7V AA Li-ion battery, ordinary electrical using a two 1.2V or 1.5V AA battery. If you use two 3.7V Li-ion battery will damage the electrical, Be sure to look at the voltage of the electrical appliances before use.
Thanks & Best regards
- freedom345
Then a while later, the seller sent this email:
Hi.
Dear friends, thanks for purchase.
In most cases, this battery can only use 1pcs, another battery tube instead, if use 2pcs 3.7V Li-ion battery, may damage the electrical, we will send the same number battery tube to you immediately by free.
Thanks& Best regards
- freedom345
So unsolicited and at his own expense, the seller shipped a package of ten (10) battery tubes (shunts), one for each battery purchased. So you could use one battery and one shunt in place of two AA batteries. Not only that, but they sent them inside some lovely polyethylene battery cases, three cases that hold 4 batteries each. Especially wonderful for storing charged batteries. Mind you, we didn't pay a penny for any of this.
Now how is that a bad thing? I think I'll order another set of ten batteries just to support this fantastic and responsible seller.
Plugging away, here he is: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251100046291
Edit: Duane beat me to it. DEGN! (Newman!)
r/c airplane users used to buy 'dummy AA batteries' so that they could use regular AA alkaline batteries instead of NiCad AA batteries in the transmitter. HAM radios have done similar things.
One point that is important.
If you build something that demands quite a bit of discharge, you need to shut down the battery before it gets too low. If you have a separate charger, that may be an issue. I have some 4-wire 3.3volt low-dropout regulators and the 4th wire shuts down the regulator. It can be wired to create a shut off threshold.
Not exactly sure what to do if no regulator is used.
I completely agree with erco (on this topic), this seller went out of his way and at his own expense to send these shunt cells so those who purchased the Li-Ion batteries could use them with normal devices.
I apologize if I made it appear I was being ripped off.
I accidentally left my RC transmitter on over night not long ago. The transmitter was being power by a 3-cell LiPo. When I noticed what I had done the next day, it was too late. One of the LiPo cells is now dead and wont take a charge.
I now use one of these on any LiPo pack I have plugged into anything.
voltalarm-18987.jpg
These are very loud so I'll should hear it from anywhere in the house. I think it's loud enough to wake me up.
They only cost $1.92. Hopefully, they'll keep me from ruining any more LiPo cells.
I also like to use the battery monitor erco had sent me.
Since receiving erco's gift, I've purchased several more.
The picture is of the HobbyKing version. They're not as cool as the red PCB version erco sent me, but they work fine and are cheap ($1.96) (I think they're even less expensive from ebay).
These are NOT exactly the same length as AA cells and may not fit in the battery holder if you are attempting to just replace conventional AA cells with half as many Lithium. I have had to work hard to squeeze then in a normal AA holder and I have yet to see a special holder just for them.
No offence here.
I hadn't noticed the extra length on these cells. You're right they are longer than other AA cells.
I grabbed a few cells I had near by and measured them.
Here are the results:
These Li-Ion cells are about half a millimeter longer than most of the other AA cells I measured.
I've previously noticed how many rechargable batteries are a little wider than alkaline cells. I have an 8-cell holder that fits inside my RC transmitter when the holder is full of alkaline cells but it doesn't fit when I use recharable cells.
I hope the extra length of these Li-Ion cells doesn't cause too much trouble for those of us using them with normal AA holders.
Thanks for the heads up about it.
I'm insulted, you think I'd be so dumb.
I only used metal calipers on the first battery. After that,
I used a set of plastic calipers to measure the batteries.
And yes, I did get some pretty good sparks.
I have been looking into shut off circuitry for a low voltage and apparently a MOSfet can be controlled by a good reference voltage and a voltage divider circuit to do the job. But it also seems many of the battery vendors have boards that do the same thing rather cheaply.
See RSJC in the thread linked to below for what I suspect is a best circuit.
http://www.eevblog.com/forum/projects-designs-and-technical-stuff/li-ion-battery-low-voltage-cut-off-circuit-needed-for-project/
After reading this artcle, I've decided it should be safe to use my LiPo charger to charge Li-Ion cells. I think these Li-Ion cells should probably be charged at a lower current than the usual 1C. The article says they should be charged at 0.8C or less.
I'll probably use .6C for these batteries. 0.6 * 1200mA = 720mA. So I'll set my charger to 720mA charge current.
In theory a LiFEPO4 charget should work with the LiMnO2 chemistry of what you term "Lithium Ion" charger, but you would definitively get less of a charge. Peak charge will be to something like 3.9V rather than 4.2V. The rate of charge may be slower as well.
Parallax's 18650 is a charger and battery holder system. That simplifies battery management as I still haven't build anything to shut down a low battery. I would hate to waste good new Lithium batteries by an over-discharge on the first round of use.
In some cases, the microcontroller can monitor and shut down the battery, but not always.