00:06 <DocScrutinizer05> >>electrochemical cells with actual polymer electrolytes, which however have not reached full commercialization and are still a topic of research<< I wonder how obsolete this statement is. Prolly I could try to find out that it been written to wikipedia a 8 years ago, but I'm too lazy

00:11 <DocScrutinizer05> hmmph https://en.wikipedia.org/wiki/Research_in_lithium-ion_batteries

00:14 <DocScrutinizer05> also https://en.wikipedia.org/wiki/Lithium-ion

01:19 <arossdotme-planb> arr so the protection boards are call BMS

01:19 <arossdotme-planb> *called

01:22 <arossdotme-planb> 1st find http://www.aliexpress.com/item/4S-20A-11-1V-li-ion-BMS-PCM-battery-protection-board-bms-pcm-for-lithium-LicoO2/32388217872.html?ws_ab_test=searchweb201556_3,searchweb201644_4_10001_10002_10005_301_10006_10003_10004_62,searchweb201560_8,searchweb1451318400_6150

01:33 <arossdotme-planb> for a 4s4p 16AH pack this looks like a good candidate http://www.aliexpress.com/item/4S-16A-11-1V-li-ion-BMS-PCM-battery-protection-board-bms-pcm-with-balancing-for/32392606560.html?ws_ab_test=searchweb201556_3,searchweb201644_4_10001_10002_10005_301_10006_10003_10004_62,searchweb201560_8,searchweb1451318400_6150

02:53 <roh> arossdotme-planb: important note: rc packs dont have balancers built-in like your notebook battery has

03:03 <arossdotme-planb> or right the BMS does that? so i would need to buy a BMS that also has balancers built-in

03:03 <arossdotme-planb> or=oh

03:03 <arossdotme-planb> urrg i mean...

03:04 <arossdotme-planb> rephrase: i would need to buy a BMS that also has balancers built-in

03:09 <arossdotme-planb> roh, got any info i could educate my self as to why rc packs dont last so long? i thought it was because they where pushed hard. being constantly discharged to 3.0v, even extra fast charged and used very near to there discharge rate limit.

03:09 <arossdotme-planb> append to 1st question in prev post: ...so long due to there build/quality ?

03:51 <roh> also i can recommend a book.. i dont know if its available online or in english... let me search for a link

03:52 <roh> http://www.batteriebuch.de/

03:52 <roh> seems only to be german. sadly not online but print on demand

04:04 <arossdotme-planb> thanks

04:19 <arossdotme-planb> roh, this protection board has a built in balancer what do you think? http://www.aliexpress.com/item/4S-16A-11-1V-li-ion-BMS-PCM-battery-protection-board-bms-pcm-with-balancing-for/32392606560.html?ws_ab_test=searchweb201556_3,searchweb201644_4_10001_10002_10005_301_10006_10003_10004_62,searchweb201560_8,searchweb1451318400_6150

04:22 <roh> ive seen both from china... worst thinkable crap and proper engineered equipment.. difficult to tell without buying one and taking it apart sometimes

04:23 <roh> the bms must match the cutoff-values of the cells you are using. this one looks like a simple one which 'burns off' what the good cells have more than the worst one to level the pack (which is ok, most packs do that))

04:39 <arossdotme-planb> so theres more advanced bms boards available... any recommendations?

04:43 <roh> not really.. ive seen some integrated ones in ebike packs which seemed nice

04:44 <roh> but thats 48V 10Ah area stuff

04:45 <roh> i use from i got from a partially broken bionx ebike pack. it even has some step up and down converters.

04:47 <roh> one is doing the charging from a 26V 3.5A dc supply into a pack which needs around 50-52V charge end voltage. so its a big step-up converter. the other one is fried, it did the ~48V discharge to ~6V stepdown for the bike lighting. its even configurable via the bus and the controller inside the pack

04:53 <arossdotme-planb> ok

04:57 <arossdotme-planb> re using 18650 cells to make a pack. as the protected ones are 3x the price (ouch!). could i have two protection boards and have two 4s1p packs that i put in parallel. each pack has its own protechion board. would this setup have any problems? the advance being that instead of having cell sets in parrel where i dont know if one of the cells is not balanced, the 4S1P + protection board X2 will take care of that?

04:58 <arossdotme-planb> advance=advantage

05:09 <roh> using cells from not the same batch is not a good idea in general.

05:09 <roh> especially when using them in parallel

05:10 <roh> you need protection per pack, not neccessary per cell

05:10 <roh> protection means overvoltage, undervoltage, overcurrent lockout

12:58 <arossdotme-planb> roh, thats what i mean, as the cells dont have protechion built in, I could add it with a BSM for each series cell lot

16:37 <roh> arossdotme-planb: i see.. well.. i think its better to only have one bms. not one per chain

17:53 <arossdotme-planb> roh, ok, idk

17:53 <arossdotme-planb> arrgh its not easy :|

17:53 <arossdotme-planb> why does a sony laptop protection board have a 8bit microchip? http://www.datasheetcatalog.com/datasheets_pdf/M/3/7/5/M37515M4-XXXHP.shtml

18:09 <arossdotme-planb> oh yea, with my prev,prev post i meant with cells that is hopefully/had better be from the same batch, from the same order.