LFS: NZ: LiPo Batteries – Nominal 3.7v, 5500mAh

[Mr.B]

I am having great difficulty sourcing 3.6/3.7v, 5000 to 6000mAh LiPo batteries in New Zealand.
Added to this problem is that the “well known” suppliers will not ship them internationally.
I have previously sourced some from SeeedStudio that were marked as 6000mAh, but were more like 5500mAh. It consisted of what appeared to be 3 paralleled 2000mAh batteries with battery protection chip.
They no longer stock the one I was purchasing.
The size of the pack is important as I must fit into an existing design. (Photo below)
Maximum of 73mm x 58mm x 22mm.
The SeeedStudio one was 70mm x 50mm x 12mm.
3 x 18650s paralleled would fit, however I am not sure how safe it is to parallel these batteries and I do not know if they have a battery protection chip.
Also, sourcing reputable brand 18650s in New Zealand seems to be difficult too.

RC hobby batteries tend to be >7v and the ones that are available at 3.7v are very low mAh.

Any Kiwis out there that know of a source?

Thanks in advance.

[sleemanj]

HobbyKing has a number of 1S cells in that capacity area - a quick skim down the listings page I found these:

http://www.hobbyking.com/hobbyking/store/__17267__Turnigy_nano_tech_5600mah_1S2P_65_130C_Hardcase_Lipo_Pack_ROAR_APPROVED_.html
http://www.hobbyking.com/hobbyking/store/__24307__Turnigy_nano_tech_A_SPEC_6000mah_1S_65_130C_Hardcase_Lipo_Pack.html
http://www.hobbyking.com/hobbyking/store/__18560__Turnigy_5000mAh_1S_20C_Lipoly_Single_Cell_.html
http://www.hobbyking.com/hobbyking/store/__18562__Turnigy_5000mAh_1S_40C_Lipoly_Single_Cell_.html
http://www.hobbyking.com/hobbyking/store/__19635__ZIPPY_Flightmax_6200mah_1S_30C_Hardcase_Car_Lipoly.html

Note that RC packs don't typically have protection circuitry so you need to handle protection (and charging of course) yourself.


Ahh, I didn't notice your size requirements, these are all too big I think.

So, 18650's, yes you can parallel them up just fine.  Make sure they are close voltage when you connect them together.  If the cells are not protected then add external protection.  Any single-cell charging/protection circuit/module can be used for parallel sets of cells, after all, once paralleled they look like one bigger cell to the outside world, of course it will charge slower. 

[Mr.B]

Thanks sleemanj.
I will test it out using two 2900mAh 18650s. That will give me 5800mAh, which is plenty in this application.
If I can find any of the type with spot welded tabs in stock in New Zealand...

Can you recommend a common protection chip?

[sleemanj]

Can you recommend a common protection chip?

The protection IC that almost every Chinese single/parallel cell product uses, is the DW01 paired with an FS8205A dual N-Fet. 

Similarly the charging IC most commonly found in such devices is the TP4056.

Unfortunately, I doubt you'll find those IC's at the likes of Element14 or RS.

[Mr.B]

Thanks sleemanj.
I have no problems with the charging circuit.
For the protection I should probably buy cells with the protection built in.
If I can find any with spot welded tabs that don't have a brand name with the word 'fire' in it... 

[Mr.B]

Update for those who are interested:
I am still trying to source 18650 Panasonic batteries with spot welded tabs in New Zealand.
In the process I have come across a single chip solution for LiPo battery protection.

Diodes Incorporated AP9211SA-AD-HAC-7

http://nz.mouser.com/Search/ProductDetail.aspx?R=AP9211SA-AD-HAC-7virtualkey62110000virtualkey621-AP9211SA-AD-HAC7

Only needs an additional two resistors and a bypass cap...  FETs are internal to the solution.

[Psi]

I wouldn't call it a reputable seller but...
http://www.aliexpress.com/item/Hot-Selling-3-7V-5000mah-Lipo-battery/32644829487.html


Also! Check out http://www.powerstream.com/
They're a good supplier and i asked them a month or two back if they could ship lithium batteries to NZ and they said it was no problem. (I was asking about large quantities of CR2032 though)

[Mr.B]

Many thanks Psi.
I will pursue those avenues and see where I get.

[Mechatrommer]

I will test it out using two 2900mAh 18650s. That will give me 5800mAh, which is plenty in this application.

check the battery actual rating before putting it in production if the figure is too important. most 18650 with claimed thousands of mAh are too optimistic, 2.9A in an hour supply? come on. https://www.quora.com/What-is-the-maximum-capacity-of-a-18650-battery i would say 0.5Ah tops for the commonly available 18650. the >1Ah are the rarest one and not the normal joe's price imho.

most rc'ers review on the net are recommending batteries sold by hobbyking and nowhere else afai can google. and the bigger size of batteries linked should give you a hint on energy density of current battery technology. i trust rc'ers are quite good at selecting this kind of stuff, if there is a battery that small that can give that big, it should be out already... the more expensive option in the hobbyking can priced triple for not more than twice the energy density and battery size reduction of the normal joe's battery technology...

[peter.mitchell]

I will test it out using two 2900mAh 18650s. That will give me 5800mAh, which is plenty in this application.

check the battery actual rating before putting it in production if the figure is too important. most 18650 with claimed thousands of mAh are too optimistic, 2.9A in an hour supply? come on. https://www.quora.com/What-is-the-maximum-capacity-of-a-18650-battery i would say 0.5Ah tops for the commonly available 18650. the >1Ah are the rarest one and not the normal joe's price imho.

most rc'ers review on the net are recommending batteries sold by hobbyking and nowhere else afai can google. and the bigger size of batteries linked should give you a hint on energy density of current battery technology. i trust rc'ers are quite good at selecting this kind of stuff, if there is a battery that small that can give that big, it should be out already... the more expensive option in the hobbyking can priced triple for not more than twice the energy density and battery size reduction of the normal joe's battery technology...

this is very easily proven incorrect.

one of the most commonly available cells, due to its price and capacity is the Panasonic NCR18650B http://lygte-info.dk/review/batteries2012/Panasonic%20NCR18650B%203400mAh%20(Green)%20UK.html a 3400mah rated cell delivering mote than 3000mah at 5A discharge
https://www.fasttech.com/products/0/10001980/1141100-panasonic-ncr18650b-rechargeable-3400mah-3-7v they are very cheap to, around $4.50 USD/cell

[Mr.B]

Thanks everyone.

I am aware of the exaggerated claims made by the "sellers"...

The 5/6Ah is all about overall capacity... Nothing to do with maximum discharge current.
The device is a WiFi temperature transmitter.
Transmit current is about 90mA for 6 to 7 seconds.
Sleep current is about 40uA.
The device sleeps for 30 minutes then transmits a temperature to a service running on our infrastructure.
Tested battery life for 5500mAh is 389 days.
This is necessary as the device can be sealed up in a temperature controlled environment for up to 9 months.

Two 18650 batteries @ about 2200mAh should be fine for the job.

The single biggest issue seems to be the new IATA regulations that came into affect April 2016.
It seems that nobody will even attempt to comply with the packaging and transport requirements.
I currently have an inquiry in with Panasonic New Zealand about supply, however they have been less than helpful so far.
If I want to buy an new 60" television, fine, but batteries.. no response so far...

[markirwin]

Hi Mr B,

Have you tried master instruments? They might ship to NZ?

Mark

[johnboxall]

Any Kiwis out there that know of a source?

Thanks in advance.

Ask Hadley from nicegear.co.nz to order you adafruit part # 353.

[Mr.B]

@tronixstuff
That is exactly what I am looking for.
I will get on to Nicegear.
Many thanks.