Dumb question

[chevys10zr2003]

Oh, OK I see my error now. Watt-hours does not matter to charge wattage. Basically you are charging at 1c.

I figured that you had a little brain fart because you are always excellent and spot on when it comes to charging stuff!

@slick2500 Sorry for going off topic and hijacking your thread.

 

[Jerry-rigged]

LOL, yeah I was like WTF, this can't be right! I knew there was a problem, but I could not spot my own error.

 

[2fast4u]

NO! You can not plug 2 batteries into the same channel. The charger won't see all of the cells. I don't think that's safe at all.

TDG, You are wrong and right in the same statement. You can plug more batteries into the same channel. However, The balancing circuit in the charger will not see all the cells individually. It will see an average. 1-2s it sees each cell, 2-2s it sees the average of two #1 cells combined and two #2 cells combined, 3-2s it sees the average of three #1 cells combined and three #2 cells combined. And so on. Therefore accurate cell balancing cannot be achieved. The more batteries there are in parallel the greater this inaccuracy can become. In the end it creates a bigger risk of an individual cell being over charged or an individual cell becoming overly discharged during use because it started out at a lesser value.
The ESC LVC only sees total voltage of however many cells that are connected in series not the individual cell voltage.

 

[chevys10zr2003]

TDG, You are wrong and right in the same statement. You can plug more batteries into the same channel. However, The balancing circuit in the charger will not see all the cells individually. It will see an average. 1-2s it sees each cell, 2-2s it sees the average of two #1 cells combined and two #2 cells combined, 3-2s it sees the average of three #1 cells combined and three #2 cells combined. And so on. Therefore accurate cell balancing cannot be achieved. The more batteries there are in parallel the greater this inaccuracy can become. In the end it creates a bigger risk of an individual cell being over charged or an individual cell becoming overly discharged during use because it started out at a lesser value.
The ESC LVC only sees total voltage of however many cells that are connected in series not the individual cell voltage.

I read somewhere awhile ago that the voltage of the cells when connected in parallel will balance and remain the same. I don't know about all of the technical terms and everything but that has been what I have always seen. Every time that I get done parallel charging I check each battery with my lipo meter and all of the batteries are always the exact same voltages. In series they won't self balance but in parallel they will.

 

[2fast4u]

I read somewhere awhile ago that the voltage of the cells when connected in parallel will balance and remain the same. I don't know about all of the technical terms and everything but that has been what I have always seen. Every time that I get done parallel charging I check each battery with my lipo meter and all of the batteries are always the exact same voltages. In series they won't self balance but in parallel they will.

I have to say that I agree on the self balancing point. I had not thought about it in that respect. Only from a charging aspect. Possibly the only real danger could stem from a battery with an issue getting in the mix and the charger not recognizing it because the average may disguise it. Or one that has a higher/lower voltage in it that melts the solder and burns your finger due to too much current on a little bitty balance wire while instantly trying to self balance

Dang it !
I just may have been right and wrong in the same statement also.

 

[olds97_lss]

I read somewhere awhile ago that the voltage of the cells when connected in parallel will balance and remain the same. I don't know about all of the technical terms and everything but that has been what I have always seen. Every time that I get done parallel charging I check each battery with my lipo meter and all of the batteries are always the exact same voltages. In series they won't self balance but in parallel they will.

That's probably more of an issue just from a safety standpoint if you have packs that aren't close to the same level... then again, parallel charging at all when packs aren't near the same level is probably a safety issue.

I guess it doesn't really matter... thinking out loud... there's 2 ways to "parallel" charge.... wait, no, I'm thinking of charging in series. If you charged in series, then you would link the packs like you do in the truck with the large cables, in series. Then the balance ports would go into a special 6 cell port, if you were charging 2 3S packs in series. Then the charger would see the 2 3S packs as 1 6S pack and balance charge each cell individually.

Anyway, if you had packs at different rates of full, you wouldn't want to put them in a parallel charge scenario, would you? Because then, the fuller/higher voltage pack would push as much current as it was physically able to into the other pack as fast as the wires would allow, which would be bad for it and bad for the other pack. Right?

Just trying to understand it a bit more...

 

[slick2500]

Lol
Still good info though.

 

[2fast4u]

Lol
Still good info though.
View attachment 21548

Ohhh, You did it now slick. Now you have to go thru this entire forum and post that at the end of nearly every thread.
Which exit you say that restroom was ?

 

[slick2500]

That's probably more of an issue just from a safety standpoint if you have packs that aren't close to the same level... then again, parallel charging at all when packs aren't near the same level is probably a safety issue.

I guess it doesn't really matter... thinking out loud... there's 2 ways to "parallel" charge.... wait, no, I'm thinking of charging in series. If you charged in series, then you would link the packs like you do in the truck with the large cables, in series. Then the balance ports would go into a special 6 cell port, if you were charging 2 3S packs in series. Then the charger would see the 2 3S packs as 1 6S pack and balance charge each cell individually.

Anyway, if you had packs at different rates of full, you wouldn't want to put them in a parallel charge scenario, would you? Because then, the fuller/higher voltage pack would push as much current as it was physically able to into the other pack as fast as the wires would allow, which would be bad for it and bad for the other pack. Right?

Just trying to understand it a bit more...

Yes you want to make sure that all packs are within something like .08v, I cannot remember exactly, I would have to look it up, so like one 2s pack at 3.6v and 3.57 and the other could be at 3.59 and 3.52v, that is also why you plug in the charge leads first, the pack will try to self balance and the leads will just melt like Chevy said.

 

[chevys10zr2003]

Yes you want to make sure that all packs are within something like .08v, I cannot remember exactly, I would have to look it up, so like one 2s pack at 3.6v and 3.57 and the other could be at 3.59 and 3.52v, that is also why you plug in the charge leads first, the pack will try to self balance and the leads will just melt like Chevy said.

Yeah and normally I plug in the charge leads and then wait a couple minutes before I plug in the balance leads to let them all equalize. I pretty much only do the parallel charging from storage charge, so all the cells are pretty much the exact same to begin with. I believe when I desoldered that balance lead I was parallel charging after running, which obviously didn't end well lol. When I'm running, I have this charger with 2 channels at 700 watts each and another charger with 4 channels at 50 watts each so then I don't have any issues keeping up with my battery demand.