16,000mah lipo packs, help me pick from two charging options

[stanson]

So I have (3) individual 6s 16k mah lipo packs for my first ebike that I am putting together. I have it narrowed down to 2 options, just seeing if one is clearly better then the other and making sure they both will work.

Opinions on my 2 trains of thought would be GREATLY appreciated.

Option 1) Since I only have 3 packs, I am leaning towards buying 3 individual 100w 10amp single RC chargers. Cost would be $150 total for (3) $50 dollar chargers. I am guessing each pack should take about 4-5 hours, IF they are capable of charging 16k packs. Running 3 at the same time, thats only 5 hours of waiting. I like this option and it seems simple. Does 5 hours charging time seem right, or are these chargers not capable of charging something that big?


Option 2) Buy a 12v 750w power supply from fellow endless sphere'er Iceman via his lipoconnection store, and pair it with a single iCharger 1000w 30amp 306b charger. I would need a parallel board, which is new unfamiliar tech to me. From what I have gathered, you would hook up the batteries in parallel, making a 48k ah pack, which would take, (guessing this is wrong!) about 2.4 hours because 48/20amp=2.4 (again I dont know how the amps work w/ 750w ps and if amp output changes when hooking multiple batteries up). Cost would be ~$230. Does calculated charging time look right?




Thoughts on if one route is clearly better?


I am beyond excited to get this bad boy running. I have never been on an ebike before, so the QS-205 V1 motor along with 74v of lipo should give quite a fun experience I have a dirt jumper frame with a 60mm rims and 2.5" hookworms. I CAN NOT WAIT.

 

[izeman]

Haven't we gone through all this in DEEP DETAIL? What information are you missing to do the simple calculations?

 

[stanson]

Haven't we gone through all this in DEEP DETAIL? What information are you missing to do the simple calculations?

I have done all I can to figure things out on my own. I am looking for confirmation.

1) I have not found feedback from those using cheap 100w chargers to fill 16k packs. I also have seen to match ah to amps, so thast 16amp charger, which is above that one, so I felt unsure. So I asked if they are capable of charging a pack that size within 5 hours.

2) In option 2, I listed a plan, and am looking for confirmation of the power supply working with the charger with the calculations I posted. I am kinda fuzzy on what the output amps will be with the 12v 750w power supply.

 

[izeman]

I mean, honestly: How can a 1000W charger not charge faster than 3x 100W chargers? 1000/300=3.33
So 1000W is about 3 times quicker. Quite simple

A 6s pack is 22V nominal. With a 100W charger it can be charged at just below 5A. 16Ah/5A=3h. All rough rounded numbers to make it easier.
A 6s pack and a 1000W charger would mean 50A charging. That's way too much for a single 16Ah pack, but for a 3x16=48Ah pack this is about 1h for charging (48Ah/50A=1h). If you use a 750W power supply only this will reduce output by a forth of course, and make charging time longer by that number.

These equations are all true based on Ohm's law and based on the assumptions that the chargers you chose can output what they claim. And as said earlier: Those are rounded numbers, so 1h is optimum. It will be 90% full in that time probably. If the cells are heavily unbalanced the balancing process can take AGES. So i recommend not discharging those packs below 3.6V for ANY cell (not average!)

 

[stanson]

I mean, honestly: How can a 1000W charger not charge faster than 3x 100W chargers? 1000/300=3.33
So 1000W is about 3 times quicker. Quite simple

A 6s pack is 22V nominal. With a 100W charger it can be charged at just below 5A. 16Ah/5A=3h. All rough rounded numbers to make it easier.
A 6s pack and a 1000W charger would mean 50A charging. That's way too much for a single 16Ah pack, but for a 3x16=48Ah pack this is about 1h for charging (48Ah/50A=1h). If you use a 750W power supply only this will reduce output by a forth of course, and make charging time longer by that number.

These equations are all true based on Ohm's law and based on the assumptions that the chargers you chose can output what they claim. And as said earlier: Those are rounded numbers, so 1h is optimum. It will be 90% full in that time probably. If the cells are heavily unbalanced the balancing process can take AGES. So i recommend not discharging those packs below 3.6V for ANY cell (not average!)

Well you have just thoroughly answered my question. That was more details than I was hoping for, I appreciate the response very much, thank you!

 

[markz]

Remember in parallel they all have to be similar voltage, like 0.01 to 0.04V, means you have to measure voltage everytime so grab yourself some $2.00 voltage monitors that can do 1-6S. Switching back and forth from serial to parallel can be a hassle, and with LiPo you have to be EXTRA careful because that one night you are tired or a bit drowsy.....

Be absolutely sure your LVC is working on your controller or you will have a fireworks show!

Out of stock but 6A per channel (4ch)
https://hobbyking.com/en_us/turnigy-4x6s-lithium-polymer-battery-pack-charger.html

Another 300W per channel
https://hobbyking.com/en_us/turbo-charger-1200w-4-300w-synchronous-balance-charger-discharger-version-2.html

These are the ones you want to spend your money on, iCharger!
https://www.icharger.co.nz/

Dual Port 8S 30A
https://www.buddyrc.com/icharger-308-duo.html

Dual Port 10S 40A
https://www.buddyrc.com/icharger-4010-duo.html

 

[stanson]

Remember in parallel they all have to be similar voltage, like 0.01 to 0.04V, means you have to measure voltage everytime so grab yourself some $2.00 voltage monitors that can do 1-6S. Switching back and forth from serial to parallel can be a hassle, and with LiPo you have to be EXTRA careful because that one night you are tired or a bit drowsy.....

Be absolutely sure your LVC is working on your controller or you will have a fireworks show!

Out of stock but 6A per channel (4ch)
https://hobbyking.com/en_us/turnigy-4x6s-lithium-polymer-battery-pack-charger.html

Another 300W per channel
https://hobbyking.com/en_us/turbo-charger-1200w-4-300w-synchronous-balance-charger-discharger-version-2.html

These are the ones you want to spend your money on, iCharger!
https://www.icharger.co.nz/

Dual Port 8S 30A
https://www.buddyrc.com/icharger-308-duo.html

Dual Port 10S 40A
https://www.buddyrc.com/icharger-4010-duo.html

Yea, thats why I kind of thought individual chargers for each pack would be simpler yet "smarter", just at the expense of a slower charging time. And thank you so much for posting those specific model links! I will definitely look at them. Appreciate the input.

 

[markz]

Yea, thats why I kind of thought individual chargers for each pack would be simpler yet "smarter", just at the expense of a slower charging time. And thank you so much for posting those specific model links! I will definitely look at them. Appreciate the input.

You do not want to skimp on the charger that is for sure!

Charge at a rate that will get the job done as soon as possible in a timely manner but still keeping the pack at a respectable charge rate.

What I normally do is if I have a 15Ah pack then a 1C or 0.75C charger rate is good for the entire pack, so a 15A charge is good, takes an hour, good for guerilla charging when out ebiking. For home use, I wouldn't want anything more then 2 hrs to charge the whole pack 100%. All depends on your budget!

I remember I bought a 50W or an 80W RC charger, and LiPo's were my first too 8) it took so so so long to charge

 

[dogman dan]

5 hours to charge is not unreasonable. 250 to 300w is not a fast charge, but its not painfully slow either. But the smaller chargers will likely need to be programmed to run that long. Usually they will have a time limit, which you will need to reset to say 7 hours, or whatever it takes. Running a balance charge will take a lot longer than 5 hours btw. Real slow going from 4.1v to 4.2. Most of the time though, you should be able to just run a non balancing charge.

Three 100w chargers will run nice on an affordable 12v or 24v meanwell. but the package will not be convenient to carry around. Why does this matter? Because you do not want to be running that charger in the house or garage.

For that reason alone, a faster solution would be nice, such as 200w chargers. But that costs more, and means a bigger power supply to run them. It will be more convenient to charge faster, for sure. 450-600w combined is a nice rate of charge to minimize the wait. 1000w is a bit too fast, unless your pack is really big. Charge too fast is not ideal for the cells, just like discharge too fast is not.

Charging outside is real inconvenient, especially with a cumbersome charger to carry around. But nothing exceeds the inconvenience of burning your house down. I got lucky, my wife and I, and all the pets survived it.

 

[stanson]

5 hours to charge is not unreasonable. 250 to 300w is not a fast charge, but its not painfully slow either. But the smaller chargers will likely need to be programmed to run that long. Usually they will have a time limit, which you will need to reset to say 7 hours, or whatever it takes. Running a balance charge will take a lot longer than 5 hours btw. Real slow going from 4.1v to 4.2. Most of the time though, you should be able to just run a non balancing charge.

Three 100w chargers will run nice on an affordable 12v or 24v meanwell. but the package will not be convenient to carry around. Why does this matter? Because you do not want to be running that charger in the house or garage.

For that reason alone, a faster solution would be nice, such as 200w chargers. But that costs more, and means a bigger power supply to run them. It will be more convenient to charge faster, for sure. 450-600w combined is a nice rate of charge to minimize the wait. 1000w is a bit too fast, unless your pack is really big. Charge too fast is not ideal for the cells, just like discharge too fast is not.

Charging outside is real inconvenient, especially with a cumbersome charger to carry around. But nothing exceeds the inconvenience of burning your house down. I got lucky, my wife and I, and all the pets survived it.

The Dogman has spoken 8)
Great, really appreciate the input. I know I've asked you this question before, so I am really grateful that you had the patience to respond again. Thank you friend.

 

[dogman dan]

I've been gone a lot since my e bike burned my garage down. Kinda lost some of the interest there, and have gone months without even looking at ES. For the last two years, I had only some tired old lipo batteries that couldn't do much anymore, down to about 60% capacity. So I couldn't even do much riding.

Along with a year of getting the smoke damaged house rebuilt, and moved back in, other things got my time and interest. Got fully retired, replaced the motorcycle, and got an RV. I am doing a lot of riding no motor bikes too, as my health is almost back to normal for my age. After 9 years, I can finally pedal again if I want to.


But its time to start riding e bikes, I can't carry the motorcycle along with the house trailer easily. So new lipo is coming next Monday. Funny how I suddenly really wanted a spare house, after having mine burn. :lol:


All my favorite chargers burned in the fire too, so my new 12s 10 ah pack will be getting charged on two 150 w RC chargers. Each charge I will undo a series connection, and each charger will do a 6s 10 ah section of battery. 250 watt hours per section, so from fully empty, it will charge in about 2 hours. ( without balancing) maybe a bit more. Most charges will be more like an hour charge though, from less that 100% empty.


If I get more battery, like 1000 wh or more again, I will want to charge faster, and might go to 60v, (18s) since I have a 1000w 60v bulk charger that did not burn.


If I make a bigger battery, then another 5 packs would get me a 1150wh 18s 15 ah pack. I would not want to charge faster than an hour, as I would if I just bought two more packs for an 18s 10 ah setup. That's too fast IMO, for them to last long. Lipo is only good for two years anyway, unless you discharge them at 1c or less.

 

[kcuf]

meanwell cc cv power supplies

bulk plus occasional rc balance charging

always safe fireproof location

further convenience add small bms charge only