Sorry if this has been covered...I promised I searched.

Ok, so I'm just now coming back to RC after a long hiatus, so I'm new to lipo. I bought a Passport Ultra charger, and the manual is less than detailed, to put it mildly. It has the settings etc. in there, but it assumes that you already know what they all mean, and just need to get to them.

Anyway, I"m not sure what to set the various parameters too. For example, if I have a 5000MAH 35C battery, what is a good number to set the max MAH cutoff at? Do you use 5000, or do you need some headroom in that setting? In general, I can't find any info on the details of charging. I've found general stuff (don't store them fully charges, balance them, don't ove-charge etc.) but no details.

Maybe there is a link someone could point me to for performance-focused charging and care of lipo's?

Thanks!

Ice charger's manual has some little detail, but its getting dated. The Team Checkpoint 1030 charger is prob a little better since it came out later. But neither have a builtin balancer so thats lacking.

I have a DC charger that works a little like the Passport in that can use capacity, time or voltage to terminate lipo charging. For capacity, since you never know if your cells underrated, I set up with headroom - usually 10-15% so for a 5000mah I'd set it at 5500mah. If it stops at 5500mah, and it will be the exact amount so you'll know what causd the termination - then reset the capacity higher next time.

You want to get capacity set high enough so the charge terminates on voltage - thats means the lipo is fully charged. If you're not getting close to 4.2v/cell, up the capacity until the terminate on voltage like they should.

Thanks for that info.

So I can expect the Ultra to detect the voltage peak and cut off when appropriate I assume is what you're saying, yes?

Also, regarding the MAH, can the charger differentiate between a partially charged and a drained battery with regard MAH specifically? In other words, is is ok to put a 3/4 charged 5000 battery on the charger with the capacity set at 5500MAH, and know that it will cut off at 5500MAH (V peak aside)?

Apart from those questions I understand. You want to figure out the true MAH capacity of every battery you have so that you can set the MAH cutoff to that +10% or so, for safety, but still assuring that the peak VDS is what cuts if off, right?

Thanks so much for the info.

Regarding discharge, the ultra defaults to 3.0VDC as a cutoff for discharge. Isn't this a little too low? I thought I'd read that you don't want to go under 3.3 or so?

"Peak voltage" is nimh terminology, for lipo, its max voltage. There really is no peak - lipo would go right on charging til there was a problem.

Since I don't have a Passport, I can't be sure, but there has to be some kind of termination order - charger should always terminate on max 4.2v/cell voltage - period. Regardless of what capacity is, if voltage reaches 4.2v/cell, lipo charging stops. The only time charger should terminate on capacity is if the "cut off capacity" is reached before the voltage reaches max of 4.2v/cell. This is the reason for the 'headroom'.

So if you charge a 3/4 charged 5000mah lipo with the capacity set at 5500, if the max cell voltage is ignored for this discussion, yes, the charger will then terminate on capacity when it reaches 5500mah. Realistically though, if cells are correctly rated, I'd expect termination when max cell voltage is reached. Its only if the cells are underrated that you'll likely terminate on capacity if you have it set to label capacity. If it bothers you, set it on the label capacity and see where it terminates.

If its 5000mah, you know it will hold more - the closer the cells are to 4.2v/cell, the less the additional mah will amount too. If the voltage is low, then there will be more to potentially add for capacity until voltge reaches cell max voltage.

If the cutoff is approached gradually, 3v is fine. The reason its set higher while running is there are big voltage swings due to big amp demands from the motor due to tigger finger 'requests' - setting lvc higher while running protects the lipos from these big demands and there resulting voltage dips. Charger discharging is much different - the demand is steady and not subject to the big swings like seen onboard.

Perfect. Thanks very much for the detailed information...I truly appreciate it.