Author Topic: Looking for 6F22 ("9V") 3S (not 2S) LiFePO4 batteries (need 9.6V nominal)  (Read 2096 times)

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Offline wb0gazTopic starter

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Looking for source/type/make/manufacturer/brand for 6F22 type LiFePO4 battery that has three cells in series (so nominal voltage is 9.6V.

Any types seen recently?

Thanks,

Dave
 

Online bdunham7

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https://budgetlightforum.com/node/53245

No US availability that I can see.  Chargers are available under the SoShine name.  If you find any, I'd be interested in knowing how well they work.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Online thm_w

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https://www.aliexpress.com/item/32820366035.html

edit: as below manufacturer verified this is NOT LiFePO4..
« Last Edit: June 10, 2021, 12:29:34 am by thm_w »
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Offline wb0gazTopic starter

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Found that soshine actually has their own web site and cites their 6F22 battery -

http://www.soshine.com.cn/a57.aspx

Looks like it's now (vs. the LiFePO4 mentioned previously) two LiPo cells.

Still looking for 3S1P LiFePO4 in 6F22.

###

New 9V Li-po Rechargeable Battery: 650mAh 7.4V

Bar Code: 6951151510211

Model: Li-7.4V-650S

 

Can charged by other 9V charger
Slim design(15.4mm)
Ready to use at any time

 

Specification:

Type:      Rechargeable  Li-Po
Dimension:(48.5+-0.5)*(26.1+-0.2)*(15.4+-0.3)mm (max)
C5mAh:  630(mini)
C5mA:    650mAh
Nominal Voltage:    7.4V
Capacity : Nominal   650mAh
               Minimum  630mAh

Internal resistance: 144-150 mΩ
when discharged at 0.2C5mA to 5.5V
Recommended Charging Conditions:0.2C5mA charge termination control parameters taper current 0.01C5mA at 8.4V
Service Life: 1,000 cycles(>=60% C5mAh,0.2C discharge)
Weight: 28 g (1 cell), 67 (2 cells with package)
Charging Voltage:  8.4+/-0.15V
Ambient Temperature Range
Charging :      0-45 centigrade
Discharging:  -20 to +60 centigrade
Storage :       -20 to +40 centigrade

 
Note:
(1) The batteries should be stored at room temperature,charged to about 30% to 50% of capacity.
(2) During long term storage,in order to ensure the battery to maintain the capacity level,we suggest Li-ion batteries should be charged and discharged once every 6 months.
 

Offline 0xdeadbeef

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That's a normal LiIon battery. For whatever reason, Soshine seems to have abandoned the LiFePO4 6F22 batteries for some years. I bought two a few years ago and now regret I haven't bought more since the two I bought work great for my Fluke 87V and a LEM current clamp. So, I'm trying to buy a few more of these batteries for two years or so. But they have vanished from the stores quite some time ago and while Soshine still sells the chargers for the batteries, there's no other hint on their website that these were ever produced or sold.
Like with many other product that were great, these LiFePO4 6F22 batteries are simply gone and nobody seems to care. Everybody seems to be happy with the LiIon batteries even though the voltage is considerably on the low end from the very start.
Trying is the first step towards failure - Homer J. Simpson
 

Offline wb0gazTopic starter

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That's what I encountered --- I imagine there's not enough market capacity for something like this given the prevalence of 7.4V nominal batteries. The only other approach I've seen is to use a 3.7V LiPo and a charge+boost module, but this is likely not a good approach due to continuous drain from the circuitry when not in use.
 
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Online edavid

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Sorry to be that person, but what's the application for the 3S battery?  I have not yet found a product where a 2S Li-ion does not work well.  Obviously 2S is going to have lower cost and higher energy density than 3S.

 

Offline wb0gazTopic starter

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No problem at all - thanks for asking!

In this case, the equipment is a small radio transmitter/receiver that needs ~9V nominal for normal operation; there is an internal non-LDO regulator (which powers an internal RF oscillator) that drops out (too) early in discharge cycle when powered by a 2S LiIon. A 3S LiFePO4 would provide enough voltage over more of it's discharge cycle, which is important for this specific device. A 3S LiPo would not work because at full charge the ~12.6V exceeds limits for some components; a 3S LiFePO4 at full charge would be ~10.8V which is within limit for those components.

Dave
 

Offline 0xdeadbeef

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Just for the record: while LiFePO4 9.6V 6F22 batteries seem to have vanished completely, there are a very few NiMH 6F22 "high voltage" batteries with 8 cells, which also have a nominal voltage of 9.6V.
  • Soshine 260mAh
  • Tensai 250mAh
  • Powerex 230mAh
  • Emmerich 200mAh
  • GP 170mAh
The Soshine 260mAH battery is totally unavailable at normal stores, the Tensai is sold out everywhere, but the other three are still obtainable. For the moment I decided to try my luck with Powerex before they are also not available anymore.

Trying is the first step towards failure - Homer J. Simpson
 
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Offline tobyinlu

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I hope someone is still following this thread.

My approach is to use 3 AAA LiFePO4's and to design an adapter.
If my measurements are correct they should fit into a standard 9V enclosure.
The advantage would be to be able to charge the three batteries separately.

What is the maximum voltage of a traditional 9v bloc?
Most vendors offer only a graph... using my magnifier I can estimate something like 10V.
What can I expect that most appliances will tolerate?
The just arrived LiFePO4 have 3.25V => 9.75V.
I expect the voltage to be higher immediately after charging.
Do I have to discharge the cells to be on the safe side?

Any suggestions welcome
Tobias
 


Online tunk

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Looky here: 
That's a 2S li-ion, not a 3S LiFePO4.
 

Online tunk

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What is the maximum voltage of a traditional 9v bloc?
Most vendors offer only a graph... using my magnifier I can estimate something like 10V.
What can I expect that most appliances will tolerate?
The just arrived LiFePO4 have 3.25V => 9.75V.
I expect the voltage to be higher immediately after charging.
Do I have to discharge the cells to be on the safe side?

Any suggestions welcome
Tobias
A new 9V alkaline is around 9.6V (assuming six cells at 1.6V).
A fully charged LiFePO4 is 3.6V, i.e. 10.6V.
If this is too high depends on the application.
 

Online thm_w

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I hope someone is still following this thread.

My approach is to use 3 AAA LiFePO4's and to design an adapter.
If my measurements are correct they should fit into a standard 9V enclosure.
The advantage would be to be able to charge the three batteries separately.

What is the maximum voltage of a traditional 9v bloc?
Most vendors offer only a graph... using my magnifier I can estimate something like 10V.
What can I expect that most appliances will tolerate?
The just arrived LiFePO4 have 3.25V => 9.75V.
I expect the voltage to be higher immediately after charging.
Do I have to discharge the cells to be on the safe side?

Any suggestions welcome
Tobias

Any drawing of the adapter?

A new 9V alkaline is around 9.6V (assuming six cells at 1.6V).
A fully charged LiFePO4 is 3.6V, i.e. 10.6V.
If this is too high depends on the application.

3.3V is 90% state of charge, so you could stop around there if you were worried, should be safe for almost anything.
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Offline tobyinlu

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Re: Looking for 6F22 ("9V") 3S (not 2S) LiFePO4 batteries (need 9.6V nominal)
« Reply #14 on: December 10, 2022, 12:38:57 pm »
It's been a while... now I have a prototype. The upper part consists of 1 mm PCB, the lower part of 1,5mm PCB milled down to 0,5mm to keep the
length within max 48.5mm.
The contacts a of phosphor bronze, the top buttons fit into holes in the PCB.
The negative contact might have short with one of top buttons. I added added an insulation ring. I think I should flip one cell for a next version.
I tried to upload more images, but  a 356kB file is too large.
 
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