hosko11

Seems no one mentions the bleed capacity of the BMS or is there a parameter I'm not understanding that tells me this or is it trial and error? If charging 12S @ 12A I'm assuming you want something that can bleed at up to 1A per channel/cell? I'm looking at this 12S BMS from Supower - http://www.ebay.com.au/itm/44V-48V-50-4V-12S-30A-Lithium-ion-Li-ion-LiPo-Li-Polymer-Battery-BMS-PCB-System-/221274094989

Not long after making the post I came across the parallel PSU idea so am going ahead with that approach - makes it much simpler. The chargers are Mean well HLG-240H-48A's. Actually managed to get 4x 2nd hand ones at a good price, so can build a charger with a conservative 16A capacity. I like the idea of the BMS as well. I imagine I'll need to parallel the balance leads for pairs of packs (series packs) to make this work? I'll dig through the thread - I'm sure the answers here already Thanks again!

Gwhy, thanks for the response. Got momentarily distracted by work and life, but back on to this project now. Assuming I go with the 4x 16,000mAh 6S to build out a 32,000mAh 12S pack does it matter if I connect them in series first and then parallel? I don't see any impact to the calculations of the packs - the constant discharge rate of 64A and peak of 160A would seem to stay the same - or am I missing something? Reason I ask is I can get hold of 2 well priced 48V (adjustable) CC/CV power supplies to bulk charge, but they're only rated to 240W/5A so was thinking of connecting each of the 2 packs as 12s and then to parallel to simplify the disconnecting for bulk charging to the 2 chargers. Hope this makes sense. Cheers, Hosko

Great forum, great thread! Using HK Multistar High Capacity batteries (4s and 6s) was raised 12 months ago, but for use with a 16.0 (http://www.trialscentral.com/forums/topic/34845-oset-batteries-lithium-lipo-conversion-directions/?p=414419) I'm planning to convert a 2015 20.0 Eco to lipo (15-20Ah capacity) and had come across these batteries thinking they looked like good options when bundled to 12s - which led me to this thread. Option 1 - 20,000mAh 6S 10C 6S1P - https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html Option 2 - 16,000mAh 6S 10C 6S2P - https://hobbyking.com/en_us/multistar-high-capacity-6s-16000mah-multi-rotor-lipo-pack.html Given ghwy's feedback to the post and the wealth of other information embedded throughout this thread, I'm unsure if they're really a great fit for the 20.0 and am looking for a sanity check of my plan. I've read; - Oset 20.0 Eco (1200W motor) is capable of pulling a peak current of 100A, possibly 150A - so I'll assume 150A - Multistar's C rating of 10C/20C is unlikely - 2C/5C seems more real world and will base battery build on that - Therefore discharge rates are; - 20,000mAh packs - Constant - 20,000*2C/1000 = 40A - Peak - 20,000*5C/1000 = 100A - 16,000mAh packs - Constant - 16,000*2C/1000 = 32A - Peak - 16,000*5C/1000 = 80A For the 20.0, am I right in thinking with the 6S packs to not exceed 5C (a 150A peak current being drawn) I would need to build two parallel 2x20,000mAh bundles (doubling the discharge rates) to then run in series to get 12s (~48V)? Using a total of 4 packs for a 12S battery with a whopping 40,000mAh, allowing a constant discharge rate of 80A and a very comfortable peak of 200A? The alternative of using 16,000mAh 6S would reduce the overall size and weight, but with a still massive 32,000mAh 12S battery allowing a constant discharge rate of 64A and a very comfortable peak of 160A. Is 64A for these 20.0 48V Osets getting a little low? Do I have the correct understanding and math on the battery build and resultant capacity? If so, I think it's back to the drawing board and find a higher C pack. Open to any and all suggestions or criticisms. Cheers, Hosko