3DXR are UK based in North Yorkshire and can provide genuine cells...
Here: www.3dxr.co.uk/product-information/li-ion-batteries/ (http://www.3dxr.co.uk/product-information/li-ion-batteries/)
The enduro cells are on sale for about £5.25p each if you want to make your own up, which sounds like a good idea to me.
Im not keen on how they have arranged the output lead TBH and think I can make a better job of it.
(https://s2.postimg.org/tpnhatpud/3_S1_P-_Power-_Tube-new.jpg) (https://postimg.org/image/tpnhatpud/)
I have a large Soldering Iron capable of soldering them, question is, how viable is soldering them...?
Id like to hear from anyone who has experience of soldering these type of batteries.....Thanks....:)
My research has shown that the best way of connecting the cells is by double spot welding and using a metal tag. Some cells are available with the tag already attached to the cell. With My experience of soldering A123 cells and NiMh I defiantly would agree. There is a plan to build an Arduino based spot welder
http://www.instructables.com/id/DIY-Arduino-Battery-Spot-Welder/
Or prebuilt here
https://malectrics.eu/product/diy-arduino-battery-spot-welder-prebuilt-kit-v3/
You weld them not solder them.
Yes, Im aware you can spot weld tags on them, however it's not very practical if you dont have one to hand.
I do have a home made spot welder from my Gas Turbine combustor making days, but it's designed to weld thin Inconel sheet metal together, Im not going to butcher it for this job.
Im sure someone has soldered them, so please feel free to leave some tips on doing it..and dont does.....Thanks..:)
:vulture:
I just solder mine together with a regular soldering iron.
Not as neat as a spot welder but does the job; no issues to date. will post a pic later...
Cheers
Quote from: FlyingRock on November 30, 2017, 05:14:01 PM
I just solder mine together with a regular soldering iron.
Not as neat as a spot welder but does the job; no issues to date. will post a pic later...
Cheers
Cheers m8, Im hoping to make a 3 cell pack in a triangular shape customised for the Z84.
:vulture:
Battery supply: www.nkon.nl (http://www.nkon.nl)
Soldering or welding?: if you have the experience, you can definitely solder these cells. Make sure you use a big soldering iron with a lot of power and use flux, so you can solder very quick and dont add too much heat to the cells (they really dont like it ;))
Or use a spot welder. There are a lot of options available. I use a DIY Arduino spot welder built myself https://github.com/KaeptnBalu/Arduino_Spot_Welder (https://github.com/KaeptnBalu/Arduino_Spot_Welder) or you can buy it pre-build https://malectrics.eu/product/diy-arduino-battery-spot-welder-prebuilt-kit-v3/ (https://malectrics.eu/product/diy-arduino-battery-spot-welder-prebuilt-kit-v3/)
Copper vs nickel: copper has less resistance than nickel http://dgroebe.free.fr/akkuwiderstand.htm (http://dgroebe.free.fr/akkuwiderstand.htm) but for what we are doing with this batteries, nickel is sufficient by all means. There is also copper band available and the DIY Arduino spot welder, if coupled with the right power source, is able to spot weld these.
Here is a thread from our german forum, lot of info, if you understand german: http://fpv-treff.de/viewtopic.php?f=32&t=8044 (http://fpv-treff.de/viewtopic.php?f=32&t=8044)
Quote from: Schalonsus on November 30, 2017, 08:29:02 PM
Battery supply: www.nkon.nl (http://www.nkon.nl)
Soldering or welding?: if you have the experience, you can definitely solder these cells. Make sure you use a big soldering iron with a lot of power and use flux, so you can solder very quick and dont add too much heat to the cells (they really dont like it ;))
Or use a spot welder. There are a lot of options available. I use a DIY Arduino spot welder built myself https://github.com/KaeptnBalu/Arduino_Spot_Welder (https://github.com/KaeptnBalu/Arduino_Spot_Welder) or you can buy it pre-build https://malectrics.eu/product/diy-arduino-battery-spot-welder-prebuilt-kit-v3/ (https://malectrics.eu/product/diy-arduino-battery-spot-welder-prebuilt-kit-v3/)
Copper vs nickel: copper has less resistance than nickel http://dgroebe.free.fr/akkuwiderstand.htm (http://dgroebe.free.fr/akkuwiderstand.htm) but for what we are doing with this batteries, nickel is sufficient by all means. There is also copper band available and the DIY Arduino spot welder, if coupled with the right power source, is able to spot weld these.
Here is a thread from our german forum, lot of info, if you understand german: http://fpv-treff.de/viewtopic.php?f=32&t=8044 (http://fpv-treff.de/viewtopic.php?f=32&t=8044)
I have a large soldering iron and a tin of flux, so I will be careful not to overheat them...
They may even turn up tomorrow, making them up yourself works out about the same price as a lower C rating Lipo of the same capacity, but less bulk / weight.
The other advantage is you get to choose how the cells are configured....
I saved some balance leads from old Lipos, so Im planning on recycling them, I may put some pics up if I dont make a pigs ear of it....lol.
:vulture:
I'd be interested in hearing how you get on, I'm thinking of doing a similar Li-ion pack for my AR Wing
Quote from: English Turbines on November 30, 2017, 05:26:46 PM
Cheers m8, Im hoping to make a 3 cell pack in a triangular shape customised for the Z84.
I second what Schalonsus said...
Here's a picture of my packs; I have mainly used 3S on the Wing Wing so far but have now started using 4S as well.
On the picture, left to right: 1) 4S LG HG2, 3000mAh/ 20A continuous work-in-progress; 2) 4S LG MJ1 3500mAh/ 10A continuous; 3) 3S LG HG2 3000mAh / 20A continuous)
Some info on my Wing Wing here: http://www.fpvhub.com/index.php?topic=52398.0 (http://www.fpvhub.com/index.php?topic=52398.0)
Happy to help if you have any questions!
Cheers
Can a spot welder for LiLon packs really be as simple as this video?
https://youtu.be/o1NFbchHeM8
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Quote from: FlyingRock on December 02, 2017, 10:00:24 PM
I second what Schalonsus said...
Here's a picture of my packs; I have mainly used 3S on the Wing Wing so far but have now started using 4S as well.
On the picture, left to right: 1) 4S LG HG2, 3000mAh/ 20A continuous work-in-progress; 2) 4S LG MJ1 3500mAh/ 10A continuous; 3) 3S LG HG2 3000mAh / 20A continuous)
Some info on my Wing Wing here: http://www.fpvhub.com/index.php?topic=52398.0 (http://www.fpvhub.com/index.php?topic=52398.0)
Happy to help if you have any questions!
Cheers
Hi M8,
I like the different cell ratings on max current draw. Im not sure what the cell ratings are for mine, but Im sure they will be ok for cruising around, I mean the Z84 will probably fly along on 4 amps or less.
I have some XT30 connectors Im going to use too, more in keeping with the pack size...My 18650s Did Not come in yesterday's post so maybe they will arrive Monday...
Spot welders are all well and good....if you have one to hand of course......:)
:vulture:
Quote from: BigT on December 03, 2017, 11:50:30 AM
Can a spot welder for LiLon packs really be as simple as this video?
Sent from my iPad using Tapatalk
Wow, that's impressive.
I was expecting that the current had to flow from one metal part to the other.
Very nice.
Much easier if you use a foot-switch and have both hands free for handling the batteries + welding tips.
Also you should press the welding tips with good pressure onto the welding point, otherwise the metal will sort of "explode" and a lot of material gets torn out.
I'm using the LG HG2 batts, on setups, where I want to save weight, by using smaller P number packs, as they do provide the necessary Amps, in most of the cases.
Now, I have seen, that some people are switching over to Sony Vtc6 cells, saying they will never order HG2's again as the Sony cells are more capable, delivering 30A and have quite a bit more juice, compared to the LG cells.
I have checked several test reviews and those VTC6 seem to do very well.
Gearbeat have a sale on the authentic Sony VTC6 now (6 days to go), $33.99 for 8 pieces:
https://www.gearbest.com/batteries/pp_571931.html (https://www.gearbest.com/batteries/pp_571931.html)
My Sanyo NCR18659GA cells have arrived...All three measured 3.55 volts, amazing.
They look nice quality and the postage was reasonable too...I also got a few other small accessories from this UK supplier.
I may have a go at soldering them up tomorrow...Im guessing draining them to 3 volts per cell is acceptable?
:vulture:
So, yesterday I soldered these cells together.
Using a large iron and some flux paste, it was pretty easy to get a fast clean join, although if I do it again, it will be easier for sure. Not sure about their capacity yet and when I charged them they took about 2300mah. There is no text printed on these cells, so not so sure about them being genuine SANYO TBH.
Oh yes, and in case you ever wondered about why they are called 18650 cells...?
18mm diameter x 65.0mm long.
My charger has a 4.10 volt cutoff point for these cells, does that sound about right because Im sure the spec says 4.20volts?
Photos to follow...
:vulture:
4.2v is the max voltage fully charged.
Glad to hear it went well, I am a bit dubious how well it will work, because of why they insist on spot welding them together if soldering is perfectly fine ?
Quote from: Coyote on December 09, 2017, 11:16:22 AM
4.2v is the max voltage fully charged.
Glad to hear it went well, I am a bit dubious how well it will work, because of why they insist on spot welding them together if soldering is perfectly fine ?
Hi Ian,
So,I can set my charger as a Lipo then and take them to 4.20 volts per cell?
Yes, the answer is easy, speed...the spot welding is a lot faster and cheaper than soldering ever will be, plus it eliminates the heat damage possibility.
Im going to run them down to 3v per cell and see how much capacity they will absorb afterwards.
Is 3v per cell ok do you think?
:vulture:
Try 3.2V first and look what your charger put in after flight
Quote from: Schalonsus on December 09, 2017, 01:50:45 PM
Try 3.2V first and look what your charger put in after flight
Oh, ok...3.20v it is then....and charging, is 4.20 v ok as well..?....My LiIon setting in my charger cuts off at 4.10 volts per cell.?
Some photos of my first attempt showing soldering, the joints look a bit dirty / sticky due to the flux residue, but they are good despite what they look like.
(https://s2.postimg.org/69le4f3jp/3_S_18650_Sanyo_1.jpg) (https://postimg.org/image/69le4f3jp/)
(https://s2.postimg.org/9gfxo1vph/3_S_18650_Sanyo_2.jpg) (https://postimg.org/image/9gfxo1vph/)
:vulture:
old Li-Ion batteries were charged to 4.1V but the new generation is chargeable to 4.2V
soldering joints looking good and solid!
Quote from: Schalonsus on December 09, 2017, 03:54:21 PM
old Li-Ion batteries were charged to 4.1V but the new generation is chargeable to 4.2V
soldering joints looking good and solid!
Cheers m8,....sooo...does this mean I can set my charger as if these were Lipos?...ie use the Lipo setting which cuts off at 4.20vdc?
:vulture:
Absolutely!
I also use LiPo program for my Li-Ions.
Most of the mid range chargers have an "auto" setting. Usually found by selecting LiPo and scrolling through the capacity setting. It's usually at the top end of the capacity setting On my HK supplied iMax for example. What I do is leave the charge on auto, select the capacity, 3s for example, connect and press start. The charger software checks and then if it is a LiFe cell it sort of knows and charges to the correct capacity with the cell count flashing. I have 2 chargers that do this. My guess is that the algorithms are generic. Maybe I will do a video to show this.
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Lithium-ion
Nominal Volts End-of-discharge Max Volts
3.6V 2.8–3.0V 4.2V
3.7V 2.8–3.0V 4.2V
3.8V 2.8–3.0V 4.35V
3.85V 2.8–3.0V 4.4V
Quote from: Coyote on December 09, 2017, 09:22:46 PM
Lithium-ion
Nominal Volts End-of-discharge Max Volts
3.6V 2.8–3.0V 4.2V
3.7V 2.8–3.0V 4.2V
3.8V 2.8–3.0V 4.35V
3.85V 2.8–3.0V 4.4V
Thanks Ian,
Yesterday, I used a largish slave motor and a 10 x 6 Prop and gently discharged the new cells over a period of 90 minutes. Individual cells stayed within 0.2v of each other.
On reflection, I dont think I discharged them low enough, because I only ran them down to 3.50v per cell.
A re-charge indicated only 2,100mah absorbed.
I need to do this test again as I think the true capacity is nearer 2,500mah, perhaps a little more.
I was a little worried about them being new cells and if they need some sort of break in period..?
:vulture:
No they discharge much lower that lipos do, 2.8v is fine.
Dont go too low with the Sanyo 18650GA's...
Look at my Skyfun video how much capacity i used at what cell voltage ;)
Quote from: Schalonsus on December 10, 2017, 12:08:18 PM
Dont go too low with the Sanyo 18650GA's...
Look at my Skyfun video how much capacity i used at what cell voltage ;)
Ok, what is the safe lower voltage limit on the Sanyos do you think..?
If Im not mistaken, your 8 cell flight pack in the Skyfun is rated at 5200mah capacity..?
This seems a little on the low side to me, as that's only 650mah per cell..? which makes my 3 cell at 2100mah seem ok..?
What is the actual capacity of that 8 cell pack do you think..?
:vulture:
I did not test it yet myself. But i flew it down to 12.8V pack voltage and used 6400mAh out of the rated 7000mAh. This is 3.2V per cell and just 600mAh left of 7000 (around 8% left)
So i dont know if it would be good idea to fly these batteries down to 3.0V or even 2.8V, really dont want you to crash your plane ;)
Just for info some discharge curves http://lygte-info.dk/review/batteries2012/Sanyo%20NCR18650GA%203500mAh%20%28Red%29%20UK.html (http://lygte-info.dk/review/batteries2012/Sanyo%20NCR18650GA%203500mAh%20%28Red%29%20UK.html)
Total difference in discharge characteristics between them and the other brands then.
Quote from: Schalonsus on December 10, 2017, 02:50:48 PM
I did not test it yet myself. But i flew it down to 12.8V pack voltage and used 6400mAh out of the rated 7000mAh. This is 3.2V per cell and just 600mAh left of 7000 (around 8% left)
So i dont know if it would be good idea to fly these batteries down to 3.0V or even 2.8V, really dont want you to crash your plane ;)
Just for info some discharge curves http://lygte-info.dk/review/batteries2012/Sanyo%20NCR18650GA%203500mAh%20%28Red%29%20UK.html (http://lygte-info.dk/review/batteries2012/Sanyo%20NCR18650GA%203500mAh%20%28Red%29%20UK.html)
Oh, those charts are interesting...So, forgive me, Im not well up on electronics, it's rated as an 8 cell 7000mah pack then? and you have verified this by how many mah it will absorb during a charge from 3.0 v per cell...?
7000mah / 8 = 875 mah per cell..?
4S Cell type pack = Discharged to an end voltage of 12.8v divided by 4 = 3.20v per cell..?
Translated to my 3 cell pack, that's an expected capacity of 875 x 3 = 2,625 mah capacity, but my cells and yours are a different brand I think..?
What charge rate in amps do you suggest for maximum absorption...?..I think I charged @ 1amp hr last time.
Dont worry, I fly without an amp counter, so rely on watching cell voltage. Im simply trying to ascertain just how these cells function with respect to voltage...which I have found pretty reliable so far with Lipos as long as the cells are draining in an even manner and have a even internal resistance, something which my charger shows during charging.
:vulture:
I use the Sanyo 18650GA rated 3500mAh per cell. This "7000mAh" pack is configured 4S2P, this means i connect two packs parallel made of four batteries in series.
So with two packs parallel i get double the capacity.
For your pack, which looks like a 3S1P you have 3500mAh and if you use Sanyo 18650GA you should not go under 9.6V
The Sanyo's can handle up to 0.5C charging current, so for 1P this would be 1.6A
When you use VTC6 or HG2 you could charge with much higher current. I think up to 3A
The Sanyo's also just have max 3C discharge rate, so for a 1P pack 10A. If u use more than 1C continues the batterie will get warm. So for small pack like yours it is better to use VTC6 or LG2, because they have much higher discharge rate and therefore a little less capacity.
"I use the Sanyo 18650 GA rated 3500mAh per cell"
That's what I find most confusing, how in Gods name can one little cell be rated at 3,500mah capacity..??????
But 8 cells only add up to 7000 mah...?
How does that work...?
Looking at the chart again, the tester actually ran them down to 2.80v per cell....but the spec implies you can take them as low as 2.5 volts per cell....So, 3 volts per cell is a good safety margin I would say.
:vulture:
If you connect them in parallel, you add up the mAh, but not the volts.
If you wire them in series, you add up the volts but not the mAh.
^^^ as above
each cell is 1S 3500mah
4 in series is a 4S 3500mah pack (or 4S1P in batteryspeak)
2 of these pack in parallel adds up to 4S 7000mah (or 4S2P)
Quote from: Dillwhacker on December 11, 2017, 09:28:27 PM
If you connect them in parallel, you add up the mAh, but not the volts.
If you wire them in series, you add up the volts but not the mAh.
Hi Dill...:)
Ok, but to me it's still a contradiction in terms, because 3,500mah per cell cannot be right, can it?
So, he has them in parallel, this is in fact two 4s packs wired together in parallel making 8 cells altogether which gives a capacity of 7,000mah at a voltage of 16.80 volts.
My 3S pack is wired in series so it's 3 x 4.20v = 12.6volts....so how do I get the capacity?...it's not 3 x 3500mah for sure.?
Im still confused....:(...... :sick:
"4 in series is a 4S 3500mah pack (or 4S1P in batteryspeak)"
Sooo...Using that logic......3 in series is a 3S 3500mah pack as well...Cant be so, can it.....??????
:vulture:
That's correct. With three in series the voltage triples but each of the cells can only output their own capacity.
In parallel the voltage doesn't change, but the available current for that given voltage triples. ( using 3 cells in each example.)
Think about energy. Volts times mAh = watt-hours = energy.
Each cell has a fixed amount of energy to give.
Wire 3 in series, you get 3 cell's worth of energy (3 times the volts at 1 times the mAh)
Wire 3 in parallel, you get 3 cell's worth of energy (1 times the volts at 3 times the mAh)
Edit: Hi ET ...
;)
Quote from: Dillwhacker on December 11, 2017, 10:13:43 PM
Think about energy. Volts times mAh = watt-hours = energy.
Each cell has a fixed amount of energy to give.
Wire 3 in series, you get 3 cell's worth of energy (3 times the volts at 1 times the mAh)
Wire 3 in parallel, you get 3 cell's worth of energy (1 times the volts at 3 times the mAh)
Edit: Hi ET ...
;)
Ah, thanks Dill....Now I think I get it...Good comparison....Series wiring versus Parallel.......
Now it makes sense.....Im still left wondering how I can make my new 3S battery pack absorb 3,500mahs though..drain em down to 2.5 volts per cell probably...lol.
I learnt something Today...Thanks to all who helped......:)
:vulture:
Ahh, well, I don't know TBH. These little cells seem to have a lot of mAh for their size, but I suspect that's because they are only rated for low discharge currents, like 1C or so. That means discharged over one hour, not 3 minutes as a mad quad would do...
Anyway, for your 3S (3 in series) pack, from flat should take 3500 mAh to charge to about 12.6 V.
I don't understand the minimum volts discussion TBH.. I thought the underlying chemistry was the same as our normal 'LiPO's.. So I'm not sure about minimum discharge voltage TBH.
Quote from: Dillwhacker on December 12, 2017, 12:04:52 AM
Ahh, well, I don't know TBH. These little cells seem to have a lot of mAh for their size, but I suspect that's because they are only rated for low discharge currents, like 1C or so. That means discharged over one hour, not 3 minutes as a mad quad would do...
Anyway, for your 3S (3 in series) pack, from flat should take 3500 mAh to charge to about 12.6 V.
I don't understand the minimum volts discussion TBH.. I thought the underlying chemistry was the same as our normal 'LiPO's.. So I'm not sure about minimum discharge voltage TBH.
Yeah, no good for any sort of Quad....lol....but for my Z84 with its tiny motor, it'll be cruising along just fine...probably will keep altitude on 3.5amps...So there's a potential 40 min flight perhaps.......50kph if I keep it aero maybe?
My 1500mm Falcon will fly for 20 mins on a 2200mah 3S if I push it.
They are small cells, but are heavier for their size compared to a Lipo...Nice thing is they won't bloat up.
According to the graph, they will indeed deliver 3500mah, or just 3,200mah if i stop at 2.8 volts per cell...Be interesting to try them out for sure.
On a small rig, they offer the possibility of making them up to suit a particular model and the space available.
:vulture:
I am wondering if any of these battery types would be good for us http://kevindark.co.uk/PublicServices/NkonFilter?ProductType=26650
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Just the Li-Ions in 18650 format are interesting.
For bigger packs:
LG INR18650-MJ1 3500mAh - 10A
Sony Konion US18650VC7 3500mAh - 8A
Sanyo NCR18650GA 3350mAh - 10A
For smaller packs:
Sony Konion US18650VTC6 3120mAh - 30A
LG INR18650-HG2 3000mAh - 20A
One of these packs would be good in my Ranger. It will cruise on 4 amps or if I want to go faster 50% throttle is 9ish amps :)
I just don't trust myself to solder them and certainly wouldn't be brave enough to try making a spot welder! I did see some once that came with tabs on, I think they were supposedly to make soldering them easier?
I also saw someone selling plastic blocks that you could use to make up packs, wish I could find the link again! I suspect they would add a lot of extra weight and bulk though which would negate the two main benefits of using the 18650's..
I am going to have a go at making a spot welder with the momentary switch. Really just for something to do and because I have most of the parts in various storage boxes, symptomatic of being a "sort of"retired builder/plumber/engineer/property developer. I have ordered some cells to try out. If it works, which I am sure it will, and I can work it, I'll weld a pack up for you. Plenty of members have helped me over the years with 3D printing, repairs etc.
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Quote from: BigT on December 13, 2017, 10:07:22 AM
I am going to have a go at making a spot welder with the momentary switch. Really just for something to do and because I have most of the parts in various storage boxes, symptomatic of being a "sort of"retired builder/plumber/engineer/property developer. I have ordered some cells to try out. If it works, which I am sure it will, and I can work it, I'll weld a pack up for you. Plenty of members have helped me over the years with 3D printing, repairs etc.
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That would be cool, thanks!
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Soldering was easier than I thought it would be TBH...:
1) Use a large Iron.
2) Abrade the surface with fine emery or similar and then wipe clean with alcohol.
3) Apply a little flux to the surface.
4) Apply the iron (briefly) to the flux to melt it.
5) Tin the surface of the cell with LMP Solder, ensure you use Leaded Solder!!!!! Don't overheat.
6) Apply pre-tinned wires to the joint and apply heat to the end of the tinned cell, (not the main wires) until it forms a joint.
7) The wire conductors in the photo are copper, which solders more readily than steel braided, it's also more conductive.
8) Lastly, solder on the balance wires, to the copper conductors / cell ends, do not overheat the thin balance wires.
Flux and Solder :
I think the Flux came from B and Q and the Solder came from RS Supplies, note, the solder is 60 / 40 type with 40% being Lead. Clean off the Flux residue with alcohol when you get finished, its acidic.
(https://s2.postimg.org/a0y862jrp/Solder_Flux.jpg) (https://postimg.org/image/a0y862jrp/)
:vulture:
hi guys
would love some advice on these little things
I bought 6 of these with the aim of wiring in series and parallel to give 6000 of 3s
however- the motor and prop setup I have is such that I would much rather run 4s.
However- this seems it's likely to be a far harder wiring issue. Is this possible ? and is it possible to balance the cells effectively like this ?
If not i will have to cope with 3s- it's not the end of the world.
Thanks :)
No, not possible with 6 cells.
You can have 3P2S or 2P3S.
If you want 4S, you need 4 or 8 cells, 4S1P or 4S2P.
:)
Ah bugger- ok thanks
Think I will have to go for 3s- the airframe won't cope with the extra 2 batteries I fear.
Any hints on how I can wire this up?
Two lots of 3 in series then wires in parallel should be easy enough- but the balance leads are confusing me?
Cheers
Better imagine you build three packs of two in parallel and wire these in series. Now the balance leads go between these in series wired packs
I found this guide quite useful.I built a 4S2P that`s 6000mAh 60a from an old laptop battery
I AIN`T FLOWN IT YET THOUGH :+
https://blog.seidel-philipp.de/diy-build-a-longrange-lithium-ion-battery/
Hmmmm ok thanks guys
Should I wire 3 pairs of parallel, of 2 triplets of series?
The latter seems best to me?
It depends on if you want 3S (12.6Volts) or 2S (8.4Volts).
If you put them in series, you add the voltage and keep the mAh the same.
If you wire them in parallel, you add the mAh and keep the voltage the same.
Ok so I got this built. It's quite time consuming really. in the end I made two 3s packs in series- and then paralleled them up to make 6500 of 3s. Pack weighs around 300g. For reference a turnigy 4000 3s weighs around 250g- so it's around 100g saving for the same capacity.
On the other hand- it cost me £35 to build. I could have had 3 multistars for that price.
Time will tell if it's worth it. One big advantage is the customised form factor.
For those who don't fancy soldering or spot welding this system could be the answer.
https://electrek.co/2018/04/17/diy-li-ion-battery/
Interesting. Will give it some thought.
Thanks
Has anyone tried the vruzend kit? This could be the perfect solution my only concern would be how much weight it would add. The main benefit of 18650 cells is the weight saving so this could impact that quite a bit