m1 cell question - Page 2 - RC-Monster Forums

zeropointbug · 02:42 PM

Oh BTW, the tabs on the M1 cells are a nickel alloy, easily solder able. The cell cans are aluminum. Which is tougher to solder, the ends aren't too bad though. They have some sort of coating which makes solder possible.

t-maxxracer32 · 12.05.2006, 05:52 PM

ty serum!

and zeropoint- the whole poin for me doing this is cause i pretty much have everything. for rigth nwo i dont wanna spend any more cash on rc since ive already put like 400 into it in the last couple weeks. maybe later i will do that though thanks!

MetalMan · 12.05.2006, 08:15 PM

Quote:

Originally Posted by zeropointbug

You mean you are going to sit there will doing a CV phase! :026:

EEK, i would rather spend $80 on the A123 charger, it will charge your pack in 15 minutes. Of course it only charges up to 3 cell at a time, you also need a balancer cable.

IMO, $80 is a rip off for the A123 charger. I can get an Astroflight 109 for $90, and that will charge 10s A123 cells. Then, I can mod the 109 to charge to 3.6v/cell AND do the CV phase, or I could charge 10s A123 as 9s Lipo (with a slight overcharge). Supposedly Astroflight is working on a chip that will allow for the charging of A123 packs.
Otherwise, the CV phase shouldn't be long with these batteries, considering that when the voltage reaches about 3.65v the cell is almost completely charged (indicated by how the cell will cause the voltage to skyrocket when a CC charge is going on).

zeropointbug · 12.05.2006, 09:32 PM

Well, for my 5s2p pack on my power supply charging, i charge them in 27 minutes. I get to CV phase at roughly 20 minutes, and then the current is still over 5 amps for several minutes, and negative exponentially dies off. So it's i guess over 85% charged at beginning CV phase.

Okay, the cheapest way to get going with A123's is buy a dewalt drill pack, or buy A123 Racing website. Then just buy the NEW Lipodapter which works with A123 cells, and charge is using a lithium charger if you have one or whatever.

t-maxxracer32 · 12.05.2006, 10:07 PM

man all this stuff you guys are saying... sheesh... ive got alot to learn... what is the cv phase?

BrianG · 12.05.2006, 10:16 PM

cv=constant voltage. cc=constant current.

t-maxxracer32 · 12.05.2006, 10:22 PM

hm... sounds cool...

BrianG · 12.05.2006, 10:28 PM

Did you want to know more? I was brief because I tend to ramble...

starscream · 12.05.2006, 10:37 PM

Quote:

Originally Posted by MetalMan

IMO, $80 is a rip off for the A123 charger. I can get an Astroflight 109 for $90, and that will charge 10s A123 cells. Then, I can mod the 109 to charge to 3.6v/cell AND do the CV phase, or I could charge 10s A123 as 9s Lipo (with a slight overcharge). Supposedly Astroflight is working on a chip that will allow for the charging of A123 packs.
Otherwise, the CV phase shouldn't be long with these batteries, considering that when the voltage reaches about 3.65v the cell is almost completely charged (indicated by how the cell will cause the voltage to skyrocket when a CC charge is going on).

I agree that $80 for a 3S charger is over priced. The FMA Direct CellPro 4S charger can now Charge & Balance A123 packs at 3Amp for $60. However, The Astroflight 109 for $90 will charge Lipo's and A123's but it will not balance them. Are you planning on configuring you packs with balancing wires? I find the whole balacing connector differences quite a PITA. It seems everyone has their own connector and I'll have to get an adapter if I want to use someone else's charger/packs.

MetalMan · 12.05.2006, 10:41 PM

I do plan on adding balancing taps, Polyquest/Hyperion style (what all of my packs use). The Hyperion/Polyquest taps seem to be the most popular, and from what I have seen, are the most popular.

t-maxxracer32 · 12.05.2006, 10:47 PM

well i just dont knwo what it is. i didnt know if it was a charging method or what lol. i need to know all i can before i go into actually doing this. has anyone made a faw or any kind of good sticky thread i can go look at? i serisouly have no clue on most of this..

thanks for your guys help thoggh!

BrianG · 12.06.2006, 12:23 AM

Quote:

Originally Posted by t-maxxracer32

well i just dont knwo what it is. i didnt know if it was a charging method or what lol. i need to know all i can before i go into actually doing this. has anyone made a faw or any kind of good sticky thread i can go look at? i serisouly have no clue on most of this..

thanks for your guys help thoggh!

Well, to make it simple;

A Constant current charge will vary the voltage to be able to push the set amount of current through the battery. This is how NiMH batteries are charged (with an extra step of detecting the peak voltage before the voltage starts to come back down). Simply: Current is constant, voltage is variable.

A constant voltage charge will output a steady voltage and the battery will pull whatever current it can. If you try to charge a depleted battery with a constant voltage, it will draw a HUGE amount of current, which would destroy the battery. Simply: Voltage is constant, current is variable.

A Lithium charger starts by charging at a constant safe current until the pack reaches 4.2v/cell (the battery voltage will rise as it gets charged). If you keep going at a constant current, the voltage will increase beyond the safe battery voltage range. So, the charger switches to a constant voltage charge. The charger maintains this voltage, but the charge current falls slowly until it is near zero, and the charge is done.

t-maxxracer32 · 12.06.2006, 07:58 AM

kinda get it but idk why youd have to do a cv phase with the a123 cells but thanks for your explanation on it!

zeropointbug · 12.06.2006, 09:47 AM

Also, maybe note worthy is the fact that the CC and CV are maximum values. Say, for A123's the max recommended voltage is 3.6 (3.8 MAX, 4.2 burst), and the charge voltage is at 5 amps. The charger will never breaking both rules at once... it will pump 5 amps in until it hits 3.6 volts, hold it there, lets the curent die off until no current at all (50mA is cutoff for A123), at which point charge is at 100% SOC (state of charge). Like Brian said.

But the think about A123 M1 cells is that they are very forgiving. You just can't give them a grudge against you. They are very durable to overcharge, under voltage cutoff, and brief short circuits (i did so myself, the tab just disappeared from a flash of light :017: )

Any other questions?

t-maxxracer32 · 12.06.2006, 10:15 AM

well i would ask for certain specs on how to charge but im going to wait for that untill i make the actuall packs. it may not be till after xmas so theres no use in me asking now.

i do have an off the topic question.. i have these 2 crazzy 3000 packs (6 cell) when i get my brushless i will never use these cause well... itd be pointless i have 3 gp3300s(that im going to convert each into 8 cells) and i have 2 ib3800s. so my question is what would happen if i took these 2 packs and made one? idk if id have to solder them together or what. but it would just be a fun pack to play around with. would it become a 14.4 3000 pack? or 14.4v 6000 pack? not really sure how that works

thanks guys!