Why not Panasonic 18650pf

S

skoleskibe

100 mW
Joined
Aug 22, 2015
Messages
35
Hi
I'm a everyday cyclist, using a xiongda XD 2speed motor to haul my fat ass to and from work every day. Until now i've been using 3 4s 10000mah multistar batteries, Works allright, but seem's to slowly loose capacity, i've done about 150cycles normaly down to about 3.7-3.8V at rest. Now i'm wondering Why not switch to 18650 type batteries, as they probably will be much safer and longer lasting. I'm not looking for High speed nor light weight but longevity and ease of use.


Looking at the best bang for my buck, i've fallen for the Panasonic 18650pf at 3.25€/piece or 3.65€ including soldertabs. Want to buy 72 pieces for a 44V 6S battery, as i have a 12S bestech bms in the mail next week.

My normal powersetting is level 3 ie 250w or about 5-6A continuos. My charge-discharge
voltages will be 4.15V - 3V, so i suppose I'll get about 15Ah out of the pack instead of the theoretical 17.4Ah

I see there is multiple different 3200-3500mAh cells out there, but the last few mAh are much more expensive than the first 2900! So Why not go for the 2900mAh pf's?

Are there any reason to go for an other battery maker?

Any thing i shall be aware of?
 
If cost is important to you. ?.you should do the $/Whr call for each cell to be sure .
Sometimes the bigger capacity cell can be almost the same $/Whr,....and that means you save weight and size by needing fewer cells for any given pack capacity.
In simple terms, higher capacity cells , mean fewer cells in the pack, with less pack weight and smaller size pack.
... But for sure the 2.9's are a good choice !
 
They rated for a max continuous discharge of 10A, so about 3.5C rated. Best used at 1C or less. Samsung 25r's rated at 8C would be a much better choice imo.
http://www.illumn.com/18650-panasonic-ncr18650pf-2900mah-high-discharge-flat-top.html
 
@ wesnewell
With 6p at 2900mAh the 1C will be 17.400mA. Thus the max 15A current draw will be less than 1C.

As described almost all my driving is in assist stage 3 which is < 250W, thus i should at 44V be drawing about 5.5A equal to about 3 hours assist or app 75km range.
 
I have the same idea as you skoleskibe that is why my next build will be 18650's instead of the multistars.

I plan on using the Sanyo 18650's 3500 MAH.

The only drawbacks I see is that they seem to take longer to charge compared to lipo or multistars.

I also don't know if the voltage range of 18650 will affect anything. It seems you may have to run them lower than lipo to get the capacity out of them and you will lose some speed.

The 18650's also need a large pack to really take advantage of the higher capacity cells like the 3500MAH.

But when pricing the 18650 they seem to cost similar to the multistars and they also should last a lot longer cycle wise. Although I only lose a few percent a year on my lipo packs.
 
@Offroader

I do at the moment charge my multistar at 4A, which is a bit too much, the bulk charger i'm using is outputting 200w. Better than my 50w iMax 6 charging at 3A but one 4S pack at a time. ;)
Thats about 10hours for a depleated pack !
The bulk charger is 2.5 hours.

The charge time will be the same as with the multistars as I'll be using the same bulk charger.

I do not worry about speed as funktion of sag, as my xiongda XD does 33km/h if i dont limit it in the advanced settings of the controller.

An other thing i'm looking forward to is that, opposed to the multistars the panasonic's do allow to go to sligthly below 3V where as the multistars do get unballanced when i go near or below 3.3V which is my lvc alarm point. ( tried it once, will not do this again).

I Think I'll stick with the PF's, they are of good reputation, really cheap @ 2.95€ and instead of a 5P pack of 3500mAh's I'll have a 6P pack of 2900mAh's. Its half a kg heavier , but cheaper
 
Im planning to go same route. PF cells from nkon 2.7€ incl shipping is unbeatable price.
22s16p 80V 46AH pack fits in my triangle wohooo!
 
@999zip999
I dont have a welder, but might make a CD welder. Or i might buy cells with solder tags.
 
,}~%#~<
The 18650PF's are gone.
So opted for the 18650B cells instead.
Just ordred 60, so a 12S5P pack is soon to emerge.. Bought them with Utag's so its only a matter of soldering it together with a
Bestech HCX D132
Wonder how many Ah i will be able to to use before the LVC @ 3V kicks in. I'm hoping to get about 14-15Ah.
 
I'm shure Samsung cells are good, but i do think Panasonic all in all makes the highest quality cells, taking in consideration not only max Amp but also cyclelife and product tollerence.
 
Panasonic NCR 18650PF
Chemistry Battery core: LiNiCOMnO2
Lithium Nickel Cobalt Manganese Oxide

Compared to Sony 18650V which I can only find as LiMn Lithium Maganese. Which I find are real safe.

Are they similarly safe?
 
Last week i pierced a pf cell while spot welding with too much pulse length (130ms instead of 30ms) that basically welded the negative on the top edge to the positive top with a 8mm nickel strip. It was the first weld i did that day and i slipped with a electrode. Dumb mistake and melted the plastic wrap and holder in a few sexonds. Pulled the cell from the melting holder with pliers and trew it out the open window with the welded tab still on it.

After 30 min it was cool to touch, leaked a bit were it was welded but fine otherwise. No fire or nothing on basically a dead short on a fully charged cell.

I have the samsungs 29E as well on a big 3~4 year old pack (400 cells 16S25P) and also had a slight user error while making that but i can still remember well that a cell went up in flames for some reason. I know it was my fault but i know for a fact the PF fails more gracefully then the 29E's.

Now i build batteries for a living and i use only PF in general or B cells if space and weight is a issue more then price.
My daily driver is still rocking the 29E's and done 45.000km now and still work fine despite my sometimes slight abuse of them. But i only charge them to 4.05v and 4.1 in winter.
 
Do take into account the maximum continuous discharge rate, as the higher energy density cells have higher DC impedance. This means under sustained loads they will sag to a point where a less energy dense cell would have delivered the same number of Wh at a higher power rating.

For example, high C-rate pouch LiPo (lithium cobalt) might only have an on-paper energy density of 160 Wh/kg, but it's still 150 Wh/kg at 15 C. In contract, an 18650 with an on-paper energy density of 240 Wh/kg might have a max continuous C-rate of about 3C, and sag to a point where you're effectively getting 160 Wh/kg anyway.
 
i would recommend and usually build my packs to have well under 1C continious discharge. prehaps 2C for peak or 3C if you are really pushing. that way the pack has a very easy life even when using high capacity/low current cells like the panny B's.
if you are building s real racer with high currents you are better off using true high discharge cells with lower capacity like a sony VCT4 or LG HB2 if you really want some decent currents with low cell counts.
 
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