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2 or more bms in series, charging in paralel
#11
(03-12-2019, 09:13 AM)DCkiwi Wrote:
(03-11-2019, 04:53 PM)Crimp Daddy Wrote: Agree… 10s BMS is ideal with a step up converter to use with your 12v supply.

Alternately, easy to find a 36v charging supply from all those hoverboards, I would just get that and simplify the setup.

that'd be a '42V' [lithium! CC/CV] charger.

10s is the key.  (3*3s != 36V nominal).

is your motor brushed, or unbrushed?  if its two-wire (brushed) this is all somewhat easier.  I prefer unbrushed myself, as they are 'waterproof' and the work is done / onus is on the controller, much more than the motor.

I’m confused… 3x3 = 9s?
 
Generally speaking, when someone says 36v battery pack or 36v charger, they are generally referring to a 10s system.  10 x 3.7 = 37v nominal, lithium max = 42vdc.
 
Even if compared to lead acid, 12v x 3 = 36v nominal, still has a max charge voltage of 43.2vdc
 
A “36 volt charger” is generally ideal for a 10s lithium setup.
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#12
It looks like somebody calculated wrong, 3*3 equals 9, not 10. But nobody else realized that.... we are specialists here, ROTFL.
1 kWp in Test
4 kWh battery target - plus Mobile Home battery
Ultra low cost
Electronics ? No clue. Am machinery engineer.
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#13
(03-12-2019, 03:35 PM)Crimp Daddy Wrote: Generally speaking, when someone says 36v battery pack or 36v charger, they are generally referring to a 10s system.  10 x 3.7 = 37v nominal, lithium max = 42vdc.
 
[...]
 
A “36 volt charger” is generally ideal for a 10s lithium setup.

um .... yes, and no.  yes, I agree with you Crimp Daddy, it is 36V nominal, BUT if one was to do a websearch for a suitable supply ... then '42V' is a better keyword to use for that search.

EVERY electric skateboard/e-scooter 10s chargers I have EVER seen (including the ones I own and use) labels itself as 42V.

some dont even put out 42V (like ~41.5V) ... just to get even funnier.

reminds me of Ireland ... Ive been told they use Miles for distance, and Kilometers for speed signage ... lol.
--    ----    ----    ----    ----    ----    ----    ----    ----    ----    --
all systems nominal... rock on.
-----------------------------------------------------------------------
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#14
(03-13-2019, 06:57 PM)DCkiwi Wrote:
(03-12-2019, 03:35 PM)Crimp Daddy Wrote: Generally speaking, when someone says 36v battery pack or 36v charger, they are generally referring to a 10s system.  10 x 3.7 = 37v nominal, lithium max = 42vdc.
 
[...]
 
A “36 volt charger” is generally ideal for a 10s lithium setup.

um .... yes, and no.  yes, I agree with you Crimp Daddy, it is 36V nominal, BUT if one was to do a websearch for a suitable supply ... then '42V' is a better keyword to use for that search.

EVERY electric skateboard/e-scooter 10s chargers I have EVER seen (including the ones I own and use) labels itself as 42V.

some dont even put out 42V (like ~41.5V) ... just to get even funnier.

reminds me of Ireland ... Ive been told they use Miles for distance, and Kilometers for speed signage ... lol.
That is all correct - and it is correct !!

10s "Blocks" is 36 Volts because the NOMINAL Voltage of LiIon is 3.6 Volt.

10 s Charging is 42 volt because the the top Voltage for Charging is 4.2 Volts....... Big Grin
DCkiwi likes this post
1 kWp in Test
4 kWh battery target - plus Mobile Home battery
Ultra low cost
Electronics ? No clue. Am machinery engineer.
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#15
(03-12-2019, 09:13 AM)DCkiwi Wrote:
(03-11-2019, 04:53 PM)Crimp Daddy Wrote: Agree… 10s BMS is ideal with a step up converter to use with your 12v supply.

Alternately, easy to find a 36v charging supply from all those hoverboards, I would just get that and simplify the setup.

that'd be a '42V' [lithium! CC/CV] charger.

10s is the key.  (3*3s != 36V nominal).

is your motor brushed, or unbrushed?  if its two-wire (brushed) this is all somewhat easier.  I prefer unbrushed myself, as they are 'waterproof' and the work is done / onus is on the controller, much more than the motor.
it's a brushed motor
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#16
(03-10-2019, 10:25 PM)edyxrp Wrote: i want to build an e-bike using a 36v 1000W motor but i face a problem that im not sure about the solution i want charge my battery pack with a 12v power supply so i will be using 3*3s bms that have to output in total 36v but im not sure about my wiring or if its possible

updates?
--    ----    ----    ----    ----    ----    ----    ----    ----    ----    --
all systems nominal... rock on.
-----------------------------------------------------------------------
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#17
what will do first pack if second/third will cut?
Building Lifepo4 Powerwall - atm 1400 cells growing

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#18
(04-24-2019, 10:44 AM)emuland-metroman Wrote: what will do first pack if second/third will cut?

Mosfets will be overstressed by reverse voiltage.
1 kWp in Test
4 kWh battery target - plus Mobile Home battery
Ultra low cost
Electronics ? No clue. Am machinery engineer.
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