Luna advanced charger

[Tommy L]

Is there a 21S version of this out there or a charger that can charge to 88.2v, but also voltage selectable to reduce voltage down to 84 or 85v 4.05v per cell??
At around 10-15amps?????

Thank you!!!

https://lunacycle.com/batteries/chargers/72v-300w-ebike-advanced-luna-charger/

 

[Tommy L]

What’s everyone’s thoughts about charging to 4.2v every time???
This is for Tesla mod 3 cells. Even Tesla cars don’t 100% charge to 4.2v per cell, so I’m told.

I got my friend to purchase the three 20P 7s packs with built in breaker/volt meter /BMS for his Gem e825 LSV. I put them in for him in series and it goes like a bat out of hell.

I’m looking for a charging solution. Something where the current drops off so the BMS can bleed while other cells get caught up if necessary.

But if 4.2v per cell charge is too much for every charge, is there adjustable voltage chargers ??
That are still 10 12 amps???

Delta QuiQ is a possibility, but I hear it has a 1amp current at the end charge. Is that too much for the final current for a BMS to bleed???

 

[goatman]

i dont go to 4.2v, i was charging to 4.1 but jumped upto 4.15v for the extra mah and i dont use a bms but ill check my pack balance every couple thousand km's.

i dont know why people balance every charge, id rather just have a bms with bluetooth for monitoring with balance turned off.

i adiust the pots inside the chargers for different voltages

 

[Tommy L]

Hey Goatman!

Gotcha..... if it’s mine.... I’m a no BMS guy.
I size appropriately to never stress my cells and usually never use more than 50-60% of my capacity.

But this purchase was for a friends 72v GEM e825
I got 3 24v premade cubes that have volt meters circuit breakers and BMS built into a steel chassis

Most people are not like us. But I’m teaching him that every 5 to 10 Bulk charges To 4.05v per cell then do a pack balance .... the packs have built in BMS and you can’t see the cell groups.

Now if it was mine.... I’d open it up and parallel into the balance leads so I can watch. Mayb I’ll do that for him later as he is just starting to learn.


https://bigbattery.com/product/24v-li-ion-battery-box-free-shipping/

 

[goatman]

the current bleeding off, i only adjust the voltage pot but typically im going down lower in voltage. i run 17s so ill adjust a 72v/20s charger down to 70.5v and the charger will automatically bleed down the amps from, just for example, 500 watts to 50 watts in the finishing stage of the charge. if you have a watt meter you can put inine between the battery and charger you can see if your charger automatically does it. some chargers have 1 or 2 more pots you can adjust the wattage/amps with.

check out vortecks to see what i mean

https://www.youtube.com/watch?v=ViORzKrOfHU

also if you do adjust pots i put a dab of silicone on screw so it doesnt move

 

[Tommy L]

I totally understand bulk charge, but when you have a BMS, it has only so much ability to bleed. I believe some that I’ve seen are around 200miliamps.
So I’m not sure if that needs to match a chargers final holding current. You want the charger to shut down once all the cells are at 4.2v and not the BMS kicking out the charge.