One of the things ive been doing lately is diy battery boxes to power my gear (sound systems and lights).
I see there’s a lack of cheap standard dimensioned battery packs. theres only popular proprietary ones. Sony camera/lighting li-ion 2S packs or drill packs, RC lipo packs but not in a hard case. this all end up being quite expensive compared to raw li-ion cells + BMS. With gadgets there seams to also be a problem. handheld computers like prya,zipit,eoma68 laptop[1],gpd pocket,etc use custom lipo cells which are very difficult to get replacements of because there not common but custom sizes.
[1] luke, the eoma68 laptop li-ion cell is a non typical right? i know its a ebike battery cell but i assume theres no typical ebike li-ion cell dimensions?
Why can’t we start cheap standard dimensions battery packs? I guess mass produced of the shelf is needed but what current company is going to start that?
We have standard dimensions lithium cell sizes like the classic 18650 but devices want flat slim lipos :/. For large packs they need to be carefully balanced cells particularly when in parallel. So having mass produced battery boxes that users replace the cells in when the old cells die, i guess is not much good due to the unknowns in how much the cells match each other? Are there other solutions?
Could we have enthusiast packs that are just in series with just 18650s in series for more Wh? upto hmm 6S? and for larger mah switch to more expensive 26650? would this be a in our power solution? would just diy people adapt it? or could products adapt it too?
oww there is AA sized lithium cells too: 14500 maybe they could fit into designs of our little gadgets instead of flat lipo cells?
if we really need small flat lipo cells, what would it take for a set of standard dimensions?
What about large say 5Ah-20Ah sized cells and getting standardized battery packs? for all those large portable speakers or portable solar pods/battery power supply box products and ebikes,etc. Currently some use lead acid retro fit lithium packs but with balancing done internally by the bms, but how acceptingly is that?
On Tue, Sep 26, 2017 at 11:56 PM, Alexander Ross maillist_arm-netbook@aross.me wrote:
[1] luke, the eoma68 laptop li-ion cell is a non typical right?
that's incorrect. it's a lithium polymer battery. it's therefore chemically stable.
l.
On 27/09/17 10:05, Luke Kenneth Casson Leighton wrote:
On Tue, Sep 26, 2017 at 11:56 PM, Alexander Ross maillist_arm-netbook@aross.me wrote:
[1] luke, the eoma68 laptop li-ion cell is a non typical right?
that's incorrect. it's a lithium polymer battery. it's therefore chemically stable.
yea sorry. I know its a polymer plastic pouch style. Apologises for using incorrect name at the time. I didn’t say anything about chemically stable, of course it is. I thought li-ion was same thing as li-po chemically but with plastic in between.
I was referring to the dimensions. which i suspect may happen to be what the ebike lipo manufacturer is making? Not questing you decision. Trying to learn about and question the status quo of lipo dimensions :)
Apologies for the long thread post btw, guess i could have simplified it some what heh.
Thanks again.
Typing on phone, please excuse top post.
Lithium ion cells are somewhat sedate, but cannot release as much current at once as lithium polymer cells can. Lithium iron phosphate cells are similarly sedare, but have capacities and discharge abilities more like those of lithium polymer cells.
Lithium polymer cells are the ones on YouTube that catch fire (or worse) at slight provocation. They tend to (pick one) melt, catch fire, or explode during recharge, if the parameters are at all even slightly off.
Most phones also use lithium polymer cells, though - usually a single flatpack in a case. These flatpacks need room to expand, whether in a case or "non-removeable" inside the phone. What happened with the infamous Galaxy Note 7 was that the designers did not pay attention to this requirement. The batteries tried to expand, couldn't, and shorted out internally as a result. Boom.
On Sep 27, 2017 9:42 AM, "Alexander Ross" maillist_arm-netbook@aross.me wrote:
On 27/09/17 10:05, Luke Kenneth Casson Leighton wrote:
On Tue, Sep 26, 2017 at 11:56 PM, Alexander Ross maillist_arm-netbook@aross.me wrote:
[1] luke, the eoma68 laptop li-ion cell is a non typical right?
that's incorrect. it's a lithium polymer battery. it's therefore chemically stable.
yea sorry. I know its a polymer plastic pouch style. Apologises for using incorrect name at the time. I didn’t say anything about chemically stable, of course it is. I thought li-ion was same thing as li-po chemically but with plastic in between.
I was referring to the dimensions. which i suspect may happen to be what the ebike lipo manufacturer is making? Not questing you decision. Trying to learn about and question the status quo of lipo dimensions :)
Apologies for the long thread post btw, guess i could have simplified it some what heh.
Thanks again.
arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
On 27/09/17 14:58, Christopher Havel wrote:
Typing on phone, please excuse top post.
Lithium ion cells are somewhat sedate, but cannot release as much current at once as lithium polymer cells can. Lithium iron phosphate cells are similarly sedare, but have capacities and discharge abilities more like those of lithium polymer cells.
arr didnt know about the quick and high current discharge of li-po vs li-ion. oh and thx for lifepo vs lipo too. thought lifepo could do high dischage but didnt know it was simular to lipo. oow i learnt some more :) thanks
Lithium polymer cells are the ones on YouTube that catch fire (or worse) at slight provocation. They tend to (pick one) melt, catch fire, or explode during recharge, if the parameters are at all even slightly off.
Most phones also use lithium polymer cells, though - usually a single flatpack in a case. These flatpacks need room to expand, whether in a case or "non-removeable" inside the phone. What happened with the infamous Galaxy Note 7 was that the designers did not pay attention to this requirement. The batteries tried to expand, couldn't, and shorted out internally as a result. Boom.
Yea tried to leave/naturally left a little bit of room in my wooden battery box. hmm guess 1,2or3mm total for front and back and 1cm or so along one side with foam to pad/fill the gap. hmm didnt do any calculations for how much space to leave. kinda assumed that i had enough/ wasn’t trying to make it a tight fit but overall compact. using the bits of wood i had for a compact, strong box. its a 4S 20AH pack... http://hobbyking.co.uk/hobbyking/store/uh_viewitem.asp?idproduct=80904
you’ve got me reassessing my decisions... hope its ok... got a temperature alarm with sensor along the side. plus 2x cell voltage monitors/alarms.
Phone again, sorry again... 10% of battery height is your minimum space.
On Sep 27, 2017 10:42 AM, "Alexander Ross" maillist_arm-netbook@aross.me wrote:
On 27/09/17 14:58, Christopher Havel wrote:
Typing on phone, please excuse top post.
Lithium ion cells are somewhat sedate, but cannot release as much current at once as lithium polymer cells can. Lithium iron phosphate cells are similarly sedare, but have capacities and discharge abilities more like those of lithium polymer cells.
arr didnt know about the quick and high current discharge of li-po vs li-ion. oh and thx for lifepo vs lipo too. thought lifepo could do high dischage but didnt know it was simular to lipo. oow i learnt some more :) thanks
Lithium polymer cells are the ones on YouTube that catch fire (or worse)
at
slight provocation. They tend to (pick one) melt, catch fire, or explode during recharge, if the parameters are at all even slightly off.
Most phones also use lithium polymer cells, though - usually a single flatpack in a case. These flatpacks need room to expand, whether in a
case
or "non-removeable" inside the phone. What happened with the infamous Galaxy Note 7 was that the designers did not pay attention to this requirement. The batteries tried to expand, couldn't, and shorted out internally as a result. Boom.
Yea tried to leave/naturally left a little bit of room in my wooden battery box. hmm guess 1,2or3mm total for front and back and 1cm or so along one side with foam to pad/fill the gap. hmm didnt do any calculations for how much space to leave. kinda assumed that i had enough/ wasn’t trying to make it a tight fit but overall compact. using the bits of wood i had for a compact, strong box. its a 4S 20AH pack... http://hobbyking.co.uk/hobbyking/store/uh_viewitem.asp?idproduct=80904
you’ve got me reassessing my decisions... hope its ok... got a temperature alarm with sensor along the side. plus 2x cell voltage monitors/alarms.
arm-netbook mailing list arm-netbook@lists.phcomp.co.uk http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to arm-netbook@files.phcomp.co.uk
On 2017-09-27 15:42 +0100, Alexander Ross wrote:
On 27/09/17 14:58, Christopher Havel wrote:
Typing on phone, please excuse top post.
Lithium ion cells are somewhat sedate, but cannot release as much current at once as lithium polymer cells can. Lithium iron phosphate cells are similarly sedare, but have capacities and discharge abilities more like those of lithium polymer cells.
arr didnt know about the quick and high current discharge of li-po vs li-ion. oh and thx for lifepo vs lipo too. thought lifepo could do high dischage but didnt know it was simular to lipo. oow i learnt some more
It's even more complicated than this. Li-ion can be almost as high-discharge as Lipo cells, but there is a current/capacity tradoff (more accurately a tradeoff between maximising capacity, or minimising internal resistance). So powertools use 18650 li-ion cells which can do 20 or 30A discharge, but these have 1.5Ah capacity, not 3Ah, which good lower-discharge cells will have.
Compare the datasheets for LG INR18650-HB2 (high power 30A:, low capacity 1.5Ah) https://www.nkon.nl/lg-hb2-1500mah-30a.html and Samsung ICR18650-29E (low power: 8.3A, high capacity: 2.9Ah) https://www.nkon.nl/rechargeable/18650-size/samsung-icr18650-30a.html
'Lithium-ion' covers a multitude of slightly different battery chemistries with different pros and cons (and ages). lithium-manganese, lithium-cobalt (early 18650s), lithium iron phosphate ('LFP', or 'LiFePO'), (both with and without ytterbium) often in much larger-format cells, lithium nickel manganese cobalt oxide: 'NMC', in many modern 18650s), and lithium nickel cobalt aluminium ('NCA'). Many are interchangeable, but sometimes the differences matter. LFP has significantly lower voltage (3.3 nominal vs 3.6) and thus energy density. LiPos normally come in pouch format and have a slightly higher charge voltage (4.2V vs 4.1V), both of which features improve energy density, but are really the same set of chemistries as Li-ion, but with a different electrolyte and format). LFP won't catch fire. Lithium cobalt can, and is highly exothermic if it does, which is one reason other chemsistries have become more popular (and cobalt is now very expensive). Lipo's like to burn too, but more modern chemistries (NMC, NCA) tend to be much safer.
And new things are happening in this area all the time, with some exciting developments in glass combined electrolyte/separators.
https://en.wikipedia.org/wiki/Lithium-ion_battery https://en.wikipedia.org/wiki/Lithium_polymer_battery
Wookey
--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Wed, Sep 27, 2017 at 2:42 PM, Alexander Ross maillist_arm-netbook@aross.me wrote:
On 27/09/17 10:05, Luke Kenneth Casson Leighton wrote:
On Tue, Sep 26, 2017 at 11:56 PM, Alexander Ross maillist_arm-netbook@aross.me wrote:
[1] luke, the eoma68 laptop li-ion cell is a non typical right?
that's incorrect. it's a lithium polymer battery. it's therefore chemically stable.
yea sorry. I know its a polymer plastic pouch style. Apologises for using incorrect name at the time. I didn’t say anything about chemically stable, of course it is. I thought li-ion was same thing as li-po chemically but with plastic in between.
I was referring to the dimensions. which i suspect may happen to be what the ebike lipo manufacturer is making?
correct.
http://hands.com/~lkcl/eoma/laptop_15in/EV%20GPNCM62135160%2010Ah%20NiCoMn%2...
datasheet.
arm-netbook@lists.phcomp.co.uk
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Alexander Ross -
Christopher Havel -
Luke Kenneth Casson Leighton -
Wookey