Fast chargers for 72 volt- li-ion pack ?
- Thread starter rumme
- Start date
999zip999
100 TW
How many ah is it ? It can depend on the bms for rate of charge. Where'd you get the battery do you have a link we need to know a lot more information.
I break mine and half as to 36 volt and I charge eats 36 volt pack at 16 amps each. But most people don't run run highest quality cells. A123 and heavy. It's always a compromise.
Most are limited by their BMS which only allows 5 amp or 8 Amp.
I break mine and half as to 36 volt and I charge eats 36 volt pack at 16 amps each. But most people don't run run highest quality cells. A123 and heavy. It's always a compromise.
Most are limited by their BMS which only allows 5 amp or 8 Amp.
999zip999 said:
It was custom built by a poster on this forum....using Samsung 22p cells....the battery can easily output 80 amps continuous , but I have no idea what brand of BMS it has.
If the BMS can only allow a max of 5 amps charge rate, would a charger that charged at 6 amps, damage it ?
Chinese cc/cv boost converter, biggest one you can find. I have one that would do around 8 amps with a 36v input voltage.
If your BMS only allows a 5 amp charge, then you will just get 5 amps. It won't be damaged unless you input too high of a voltage. That sounds like one lame ass bms though. I charge my batteries close to 1C. If you ditch the BMS don't exceed 1C and your cells should be just fine.
If your BMS only allows a 5 amp charge, then you will just get 5 amps. It won't be damaged unless you input too high of a voltage. That sounds like one lame ass bms though. I charge my batteries close to 1C. If you ditch the BMS don't exceed 1C and your cells should be just fine.
I'm sure the BMS can handle 6A, even if it has only one charge FET. BMS heating is the limiting factor. If you can get a look at the BMS, you can estimate the charge current limit by seeing what it has for charge FETs. A 22p pack can probably handle at least 40A charge current.
None of the common BMS units I've seen have any kind of current limiting that PWMs the input voltage to reduce the current. Some might detect the current and shutdown the input completely if it's too high, but the ones I've worked with dont' have a shunt on the input side, only the output.flat tire said:
So the current, if too high, would heat the input FETs more than the BMS was spec'd for. If the spec is conservative, that's ok. If it's not, then there's risk of FET damage, and if it goes high enough long enough, and there's enough heat buildup, it's possible to melt the solder on the FET(s). Depending on where that solder goes (mostly how the BMS is oriented vs gravity), then some very bad things can happen. :/
Exactly what results you'd get for any given BMS and charge rate, you'd have to experiment to find out.
dogman dan
1 PW
Fast charge naked, if you need it that fast. Bypass the bms, and ideally, undercharge by setting the charger to .05v per cell low.
I have the bigger charger from bms battery, and so far its working ok for me. I think its the 800 w. (10 amps) Kind of liking the fast charge, on a 15 ah lipo pack. So for me, no bms to worry about. Mine is the old one, from several years ago, looks like they have newer versions now at bms battery.
If you have a bms, then finish off with the slow charger when you want it balanced.
I have the bigger charger from bms battery, and so far its working ok for me. I think its the 800 w. (10 amps) Kind of liking the fast charge, on a 15 ah lipo pack. So for me, no bms to worry about. Mine is the old one, from several years ago, looks like they have newer versions now at bms battery.
If you have a bms, then finish off with the slow charger when you want it balanced.
DrkAngel
1 GW
Need to know the Ah!rumme said:
Samsung ICR18650-22P are rated at .5C normal charge or >> .8C rapid charge (with diminished lifespan)
72V 4.4Ah? = 2.2A >> 3.52A
72V 8.8Ah? = 4.4A >> 7.04A
72V 13.2Ah? = 6.6A >>10.56A
72V 17.6Ah? = 8.8A >> 14.08A
999zip999
100 TW
Yes ? Samsung 22p cell or 22 cells paralleled.
DrkAngel
1 GW
72V 22Ah = 11A >> 17.6A = 20s10p (200 cells)DrkAngel said:
72V 26.4Ah = ≤13.2A normal charger >> ≤21.12A rapid charger = 20s12p (240 cells) 12x 36V 4.4Ah oem packs
10-12 Amp charger looks ideal.rumme said:
880-1000w charger or regulated current power supply.
2 x 48V 400w power supplies in series could supply 84V 9.5A
Requires current (Amp) mod on, at least, 1 and setting both 48V PS to 42V
See - Meanwell clone- AD488.3-400W power supply mods
DrkAngel
1 GW
skeetab5780
1 MW
Just because it puts out power doesnt mean it is a battery charger.
rumme said:
Have you checked out the products at http://chargery.com/ ? I am using the combo charger and bms shown on the website front page. It is great. The USA distribution guy is a member here. Just do a search for Chargery on this site. The 24s 1-25amp charger is really nice. Can do upkeep charging and benchtop power supply modes as well. Worth a look.
YS
DrkAngel
1 GW
.
... Charger + power supply
Most chargers have the advantage of a positive disconnect at some minimum current.
3 Amp charger can be teamed with a 7 Amp power supply.
Determine actual charger output (4.17V per cell = 83.4V
Set power supply at ~83V, isolate with a diode on the positive line (Diode might supply the appropriate voltage reduction .7V is typical)
Parallel charger and power supply
Power up charger 1st
attach to battery or battery BMS
Power up power supply
= 10 Amp charger, with all extra function of charger
7 Amp power supply contribution stops when charge nears completion.
3A charger finishes charge, including any BMS functions
... Charger + power supply
Most chargers have the advantage of a positive disconnect at some minimum current.
3 Amp charger can be teamed with a 7 Amp power supply.
Determine actual charger output (4.17V per cell = 83.4V
Set power supply at ~83V, isolate with a diode on the positive line (Diode might supply the appropriate voltage reduction .7V is typical)
Parallel charger and power supply
Power up charger 1st
attach to battery or battery BMS
Power up power supply
= 10 Amp charger, with all extra function of charger
7 Amp power supply contribution stops when charge nears completion.
3A charger finishes charge, including any BMS functions
wineboyrider
1 MW
What Dogman said, but do you need an opportunity charger or a home charger?dogman dan said:
DrkAngel
1 GW
Power supply fills that function.rumme said:
Many subscribe to the theory that the finishing trickle charge is detrimental to cells.
"Charger" actually shuts off slightly sooner and discontinues charge, theoretically, avoiding a type of deterioration.
wineboyrider
1 MW
Yep. Constant current constant current chargers taper the charge toward the end. i currently use meanwell hlg led chargers for a 10 amp charge, but I use HK Multistar batteries.DrkAngel said:
dogman dan
1 PW
One of the reasons I suggested undercharging to get it fast, is the last .05v per cell is the slow part. Any bulk charger can do it fast enough to 4.15v per cell, compared to a finished, through the bms, balance charge.
10 amps Bulk charger not that expensive, at places like bms battery. But an 800w power supply can bulk charge too, and finish off quicker, to 4.15v.
10 amps Bulk charger not that expensive, at places like bms battery. But an 800w power supply can bulk charge too, and finish off quicker, to 4.15v.
Thanks for the replies.
If I decide to use a 800 watt power supply off ebay , these run ont AC ? If they run on AC, do I need to do any type of modifications to it so it will safely charge my 72 volt li-ion pack at 10 amps ? I did not want to take the shrink wrap off my battery to disconnect the BMS for fast charging. Id rather charge thru the BMS.
How much do these 800 watt power supplies usually cost ? Thanks.
If I decide to use a 800 watt power supply off ebay , these run ont AC ? If they run on AC, do I need to do any type of modifications to it so it will safely charge my 72 volt li-ion pack at 10 amps ? I did not want to take the shrink wrap off my battery to disconnect the BMS for fast charging. Id rather charge thru the BMS.
How much do these 800 watt power supplies usually cost ? Thanks.
999zip999
100 TW
If you have access to the cells I would put four sets of 5S sense wires so I can check it with a cellog ect.
