Charging lithium batteries

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
So I was reading The Battery University on lithium batteries. I tend to use a lot of AA in AAA rechargeable batteries because I dislike buying new batteries to throw them away when they are used. Charging lithium I think is very similar to charging SLA batteries. Any opinions or suggestions?

One of the things I found most interesting, is it they strongly advise not charging the batteries to the Max apparently they do not have a memory like 9 Ni Cads do.

  • Turn off the device or disconnect the load on charge to allow the current to drop unhindered during saturation. A parasitic load confuses the charger.
  • Charge at a moderate temperature. Do not charge at freezing temperature. (See BU-410: Charging at High and Low Temperatures)
  • Lithium-ion does not need to be fully charged; a partial charge is better.
  • Not all chargers apply a full topping charge and the battery may not be fully charged when the “ready” signal appears; a 100 percent charge on a fuel gauge may be a lie.
  • Discontinue using charger and/or battery if the battery gets excessively warm.
  • Apply some charge to an empty battery before storing (40–50 percent SoC is ideal). (See BU-702: How to Store Batteries.)
 
Last edited:

dl324

Joined Mar 30, 2015
16,840
Charging lithium ion is different than SLA. I just buy a charger.

I've switched to 18650 batteries for flashlights requiring 3AAA in a cylindrical holder. That requires a tube extension for many flashlights. 18500 will work without an extension, but a spacer ring would be recommended.

I modified an LED magnifier that took 3AAA to use a 16340.
 

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
Lithium come in a variety of voltages such as 1.5V, and 9 V. What little I read (and I do not always understand what I read) is you're using constant current until it gets very close to the rated voltage, and probably should stop there.

I am interested in the charge circuitry.

Think in terms of battery backups.
 

BobTPH

Joined Jun 5, 2013
8,807
As you said, it is constant current up to the final terminal voltage, then constant voltage until the current drops to (I think) 5% of C. This is for the 3.7V nominal Lithium Ion cells with 4.2V as the terminal voltage.

I have never heard of a 1.5V rechargeable lithium battery. Can you link to one?

Bob
 

BobTPH

Joined Jun 5, 2013
8,807
Yep, just as I thought! I like the design of the one I linked, that you just plug a usb charging cable directly into the battery, no need for a special charger.

Bob
 

MrSalts

Joined Apr 2, 2020
2,767
If you are looking for RECHARGABLE lithium with traditional nominal voltages of disposable alkaline batteries, then the batteries have onboard chargers and you just plug a 5v supply into them OR, they come with a dedicated charger.

Lithium battery chemistry does not align with traditional alkaline voltages, so there is circuitry in between the lithium polymer, lithium phosphate or lithium iron phosphate or what ever new chemistry is on the market. Don't build your own charger for these batteries with the circuitry between your use and the lithium.
 

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
Lithium rechargeables have a much longer life. And I don't want any small charging hole built into the battery. I wonder if they can be used middle of a charging cycle? That might be a good compromise. Like I said standby batteries.
 

bassbindevil

Joined Jan 23, 2014
824
Memory effect in nicads is mostly a myth. It only occurs in rare situations where a battery is repeatedly charged and discharged to the same depth day after day. That happened on satellites with solar panels, but rarely if ever on earth. What we probably blame on "memory" is when a battery is over-discharged and the weakest cell in the battery is reverse-charged, which just weakens it more.
 
Last edited:

Audioguru again

Joined Oct 21, 2019
6,672
Would you buy batteries from Amazon or ebay that are made in China by a company that nobody ever heard about? Using a "special formula" using a small 4.2V battery with a low mAh rating and a voltage regulator inside to reduce the 4.2V down to 1.5V?
They have no detailed datasheet that Name Brand batteries have.

I use many Energizer Ni-MH AA and AAA batteries that are made in Japan maybe as rebranded excellent Eneloops?

Beware! Costco sells a Duracell charger that comes with four AA and four AAA Ni-MH battery cells at a very low price. They are made in China and have half or less the mAh of Energizer cells.
 

Thread Starter

Wendy

Joined Mar 24, 2008
23,415
I don't care where they're made I do care about how they work, the ones I've gotten so far are excellent.

I was quite surprised to find out the amount of electronics in one cell.
 
Top