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imax b6 can it discharge multiple 18650?
#1
Hi, i just purchased the imax b6 to test my 18650 cells capacity.
Is it possible to test multiple cells at once or i have to do it for each cell every time??
Cause if no possible i will have to return it, it takes about 5hrs to discharge each cell and i need to test about 80 cells!

Please if somebody is online advise me cause i need to return product today!
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#2
The only way you would test multiple cells at the same time is with the cells in series and with the balance leads attached.  That said, your capacity reading would only be valid for the cell which triggered the discharge termination by voltage.

So in reality, these chargers would useful for capacity testing when doing single cell testing, or if testing a group of cells in parallel to get your total capacity of a group in parallel. 

These chargers are very useful because they allow for different types of testing, including complete pack testing, and help with battery management and maintenance.

At the end of the day, you should have both.  Balance chargers and inexpensive single cell capacity testers.

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#3
so if i create a 20p pack and i connect it with imax B6 it can balance each cell?I guess not but i have to ask!
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#4
(12-20-2019, 07:00 PM)alex_1978 Wrote: so if i create a 20p pack and i connect it with imax B6 it can balance each cell?I guess not but i have to ask!

If you connect a 20p pack, all the cells are electrically connected in parallel therefore in balance with each other by default.
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#5
Oh boy.......that was funny
chuckp and Crimp Daddy like this post
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#6
(12-20-2019, 11:04 PM)Crimp Daddy Wrote:
(12-20-2019, 07:00 PM)alex_1978 Wrote: so if i create a 20p pack and i connect it with imax B6 it can balance each cell?I guess not but i have to ask!

If you connect a 20p pack, all the cells are electrically connected in parallel therefore in balance with each other by default.

Yes but what if cell1 has 1700mah capacity, cell2 2400mah capacity etc etc?Will i max charge/balance each cell to 4.2V maximum and then continue to the other?

Actually i plan to create a 3s25p or 4s20p pack and charge it via solar charge controller. Controller can adjust the maximum voltage , so let's say i set it to 12.7V for the 3s scenario. Will the charge float balanced to each cell automatically?

Sorry for changing the subject but my main goal is the balancing, that is why actually i bought the imax b6 . Will i need it?
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#7
to test capacity of 80 cells you need the opus btc3100, it test 4 cells at a time. If the cells are "new" you can just build your 3s26p pack and test the overall capacity with the imax, it can easily do that as long as the pack has a 3s balance connector (cost about 1 dollar). The imax will also balance charge a 3s pack. If the cells are used, you need to capacity test every cell, no way around it. Most of us do have a balance charger (imax or similar) to charge or test our packs when built. 

Since you mention you will be charging with solar, you need to go with a 3s battery, 4s (16.8 volts) voltage will be too high for most solar controllers.  My controller for instance maxes out at 15.5 volts, it won't charge a 4s. The bms is what will manage the balancing on your battery.

My recommendation is get the "chargery bms8" bms for your pack, its the only bms that will work without problems with lithium and solar. It also balances at 1.2 amps per cell, which is as good as any balance charger.  With solar you need to disconnect the panel when the battery is full, otherwise you get voltage surges. The chargery will disconnect the panel through a external relay. Its a failsafe system. I been using the chargery bms for almost a year 24/7, its been perfect in safely charging my lithium battery.
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#8
Just use a proper mppt Charger for solar instead fiddling around with external relays and mcgyver it
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#9
(12-21-2019, 08:38 AM)alex_1978 Wrote:
(12-20-2019, 11:04 PM)Crimp Daddy Wrote:
(12-20-2019, 07:00 PM)alex_1978 Wrote: so if i create a 20p pack and i connect it with imax B6 it can balance each cell?I guess not but i have to ask!

If you connect a 20p pack, all the cells are electrically connected in parallel therefore in balance with each other by default.

Yes but what if cell1 has 1700mah capacity, cell2 2400mah capacity etc etc?Will i max charge/balance each cell to 4.2V maximum and then continue to the other?

Actually i plan to create a 3s25p or 4s20p pack and charge it via solar charge controller. Controller can adjust the maximum voltage , so let's say i set it to 12.7V for the 3s scenario. Will the charge float balanced to each cell automatically?

Sorry for changing the subject but my main goal is the balancing, that is why actually i bought the imax b6 . Will i need it?

As I mentioned above, they are electrically connected in parallel.  Cell groups in parallel, as far as the charger knows or cares, is one battery.  Add 1700mah + 2400mah and the voltage is the same, therefore balanced.

If you are referring to cells in series, the total capacity will be based on the lowest capacity cell group. If you use the imax to balance, it will only be balanced at one voltage, usually a top balance, so fully charged it will be balanced, and as it discharges, it will have a wider mV delta between groups. You would select a termination voltage which protects the lowest cell groups.

A BMS or active balancer is a band-aid fix for batteries which are not in balance or is often times going out of balance.
 
Your solar charge controller has absolutely nothing to do with maintaining pack balance between various groups in series.  You should have a BMS capable of monitoring and balancing as these are not functions of a typically solar charge controller.
 
These statements ignore any IR variations for high drain applications because we are designing for powerwalls at 0.5C or less.
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#10
(12-21-2019, 07:25 PM)daromer Wrote: Just use a proper mppt Charger for solar instead fiddling around with external relays and mcgyver it
i plan to get the victor mptt solar and connect it with my 300W solar panels., this is not problem.
If i make a 4s20p or a 3s25p pack would the mptt charge controller to take care of overvoltage/highvoltage each cell?
Main problem is that cells are taken from diferent laptops so they absolutely have not the same capacity or resistance.
That is why i wanted to test capacity and then with the use of repackr.com to align each cell.t 
They all keep a good charge at 4.2V for months that i've tested, this is the only good thing i know.
So if i charge one by one to 4.2V, make sure they are 100% and then build the battery pack will they discharged balanced?
Would be a big risk to connect this pack to 3.5A 12V fridge for example? or just keep it for LED lights (all of them about 2A max)
And last thing i was wondering, if i solder or spotwelder the cells for the parallel boxes , then how i will be able to read voltage for each individual cell in case i need to check if is low or high voltage?
I am a little bit confused only because cells are not equal to characteristics so won't some of them get low/peak voltage from time to time?

Thanks.
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