Hey everyone

Ive recently bought a Hpi vorza flux which is my first RC car i'll use lipos with.

Ive bought 2 4200mAh 40c 7.4V 2S lipo batteries and a imaX B6 duo charger

On the first time i charged it, it took 55 minutes to charge and then i ran the car for about 10 minutes not full throttle either

Now ive just tried to charge it and its 110 minutes and still charging... is this normal???

my settings on the charger are as follows

Lipo charge: 4.0Amps 2S
Lipo discharge: 2.0A 6.0V (2S)
Lipo Storage: 0.1A 7.4V (2S)
Lipo Fast Charge 0.1A 7.4V (2S)
Lipo Balance: 4.0A 7.4V (2S)


Can anybody tell me if those settings are correct as i'm new to lipos

No reason to use the discharge mode unless you want to take a full pack down to storage voltage

Your packs should be at a resting voltage of 3.7v or so before charging, meaning your LVC would be set at 3.4 - 3.5v

A 1c charge rate for a 4200mah pack would be 4.2 amps and should take 60 minutes or so from empty

Fast charge should only be used if you are in a hurry, otherwise you should be balance charging it

Cheers

if you charge a battery at 1C, it should take 1 hour charge to full.

Let's first specify that the information bolded above is PER CELL not PER PACK. Your LiPos have 2 cells per pack. So, your resting/storage voltage should be in the neighborhood of 7-7.4V and your LVC (low voltage cutoff) should be no lower than 6.8V.

Your charger settings look good to me. I can't speak to the Vorza's power draw, but I have a couple of 4200mAh batteries and I can get 20-25 minutes per pack under race conditions with a buggy and truck both running high timing values and high gearing with 9.5 motors in them.

i believe he was implying 3.7 as a 'per cell' voltage since he is not running a 2s pack in the vorza, he is running (2) 2S packs wired in series for a 4s pack. the esc is also set up to be programed for a cut off of per cell, and not per pack.

You cannot "imply" anything with someone new to LiPo. His words were: "packs should be at a resting voltage of 3.7v". This could cause someone new to LiPo to dangerously over-discharge a pack. We need to be precise in our language with these things. Some ESC's (mine included) have an LVC set for pack voltage, not cell voltage. So, that is just a variable thing.

The iMax chargers can have probs with balancing, it should only take about an hours as stated earlier to charge lipo - it doesn't matter what size of cell count, charging at 1C (4amps in your case) they'll all take about an hour to charge. Do you know what your esc's low voltage cutoff is set at? When you connected the lipos to the charger, did you look at the individual cell voltages to see how much different they were? The diff between cells in the same lipo - thats what the charger is trying to balance.

Any chance you mistakenly selected lipo fast charge? To help understand about lipos give this a read -

http://www.rchelicopterfun.com/rc-lipo-batteries.html

I think the ESC cut off is on by default, but ive never ran the car for that long ... enough for it to cut off.. Ive just done short burst with it here and there, basically a test drive the first time... Put it this way it was only running for about 4 minutes worth of run time maybe less.

Well i didn't really set the charger to anything, just on lipo setup and put those figures in and charged it.

The only thing i don't understand is the lipo storage and fast charge rate.... also the discharge i don't know a way to turn that off. I don't know if the imax balances and discharges it by default either.

Currently the discharge rate is at 2.0A. I stoped the charger at 110 minutes yesterday and ran the car.. it runs fine... Rightfully i'm told i should charge the battery at 4.2A since its a 4200mAh bat.. I'll try that tonight and keep an eye on it

ALso the Imax just lets you put all those settings on, charge rate, balance, fast charge storage etc etc and you start it.

I think the charger does the balancing and discharge everytime.......I don't run RC cars for long or hard either, i'm more of a casual person with RC cars, i run short burst in a straight, throw a few corners and really i'm done.. if i bash a RC car it'll probably be the Bandit

oh man! i think you are missing out on where the vorza shines! this thing is a tank, dont baby it!!!

The charger is operated by selecting a charge mode and lipo has several diff modes - lipo balance mode, lipo charge mode (no balancing), lipo fast charge, lipo sorage mode and lipo discharge mode.

The charger only does the mode you select. You will not need or use discharge mode - so 2amp is ok since you're not going to use it. Discharge in your RC, its much faster that what you can do in the charger - the charger is discharge watts limited and it'll take literally hours and hours.

Always use lipo balance - that is the safest way to charge. Lipo FAST charge is for racing where time is limited and you're willing to take about a 90% charge as a full charge, you prob won't be using it either. Lipo storage is one mode you will be using. Lipo lasts longest when it is not left fully charged for any longer than necessary. When I run, I usually come home and storage charge mine so they will be at storage voltage until I get ready to use them again. I charge them for running right before I go out to run that way I minimize the time they spend at full voltage.

Chargers are more effective if they have to charge a lipo to get back to the storage voltage thats usually 3.7-3.8v/cell. You can increase the rate a littel, I use 0.1 to 0.5amps depending on the size of the lipos, bigger mah I use a little higher rate. You want a slow charge to storage since you're interested in storing at what's called the resting voltage.

threads old figured i would ask anyways ,, i have three 2s 4200mah 65c packs and a hitech ac1 plus charge i was gonna charge at 4.2v but the batteries say they they are fast charge capable , is that just higher amps i think i can only go to six amps but at least the charger balances , probably wont ever store them ill be using them every weekend