Barritia

Hey guys I'm not sure exactly what's happening here. I have tried with 2 different chargers and same effect. One is a team Orion twin spec adavantage and the other is a venom pro charger. Batterys just keep chargeing on both chargers and not cutting off. I'm charging at 3.3amps on both and its been over 1.5 hours and they are still only at 3.82v per cell.

Is this normal on new batteries as I'm quite new with li-po and I have also double checked voltages with a good quality MM and it's showing pretty much same voltage.

Duster_360

iTrader: (21)

Thats huge mah for it to only be at 3.82v/cell (roughly 41% capacity).

Are you absolutely sure you're charging on lipo mode? Its not cutting off since its not getting to 4.2v/cell (max cell voltage). As long as you're charging in lipo mode and its operating correctly, the CC/CV mode will terminate after voltage has reached 4.2v/cell.

both chargers are operating correctly in lipo mode, it sounds like both chargers have serious accuracy issues with their mah measurements. One charger I might understand, but two? Doesn't seem likely. That number simply can't be what it appears to be.

How old are these lipos, how many cycles? What brand, mah, C rating? You're balance charging?

burnineyes

iTrader: (17)

I agree, something sounds very strange. At under 1C rate (3.3A on a 5000mah pack), it will take over 1.5 hours to charge a depleted pack, but it should not be over 7000mah showing at all. The only reason I could see that is if the pack is way out of balance and the extra mah is going into the balancer. I have a cheap ebay pack that is always out of balance and it is not uncommon to see the charger showing numbers much higher than the pack really holds. Since the charger is fighting the unbalanced cells alot of the energy from the charger is simply wasted. I know at least with the Venom you should be able to see individual cell voltage, make sure they are reasonably close while charging. If the charger is struggling to balance the pack you may have better luck lowering the charge rate until the cells balance.

Barritia

Thanks guys but i think i found the problem? The charger didn't add any power to the battery at all. It was showing it was and voltages for each cell were increaseig very slowly but no amps at all. I then disconneted the battery on channel one and it still kept charging. Seems the charger is faulty as I tried the second channel on the twin spec and it works fine. Seems I thought it was doing the same thing on my venom but I was paying more attention to the new charger and the venom is working fine.

The discharge function on channel one does work and beeps when I disconnect the battery but not when charging. Must have a bad charge circuit on channel one. I'm also not impressed by the settings on this twin spec charger. Says I can discharge to 10 amps but won't let me go any higher than 3.3 amps and even at them dicharge rates the charger overheats and needs to cool down for 10 mins every 2 mins of discharge not really much use when your using the cycle program as it takes all day to even do 1 discharge cycle at 3.3amps it won't even let me go any higher than 4.4 even though it says it can do 10amp discharge per channel it also won't let me adjust my psu settings so it know what amp and voltage psu I have

Looks like is thing is going back. Next one better not have all the issues this one has.

racer1812

iTrader: (31)

You're not cycling your lipos are you?

Barritia

I was reading the instructions with the cells to cycle them 3-4 times at 8.0c discharge and no more than 1c charge for the first 3-4 cycles. Any reason not too? Charger even has a cycle setting for lipo's

Duster_360

iTrader: (21)

Generally when they tell you to do this to breakin the cells, they assume you'll run them at reduced throttle in your RC, not on a charger. Its a lot faster (and more fun) to run them, just do it at reduced throttle.

The catch on dishcarging is to find the discharge rate and discharge watts in the specs for the charger. If your charger says it can discharge at 10amps, but the dishcarge watts are only 25watts, then you'll practically never see the full ten amps because the charger will limit the disch current to stay under the disch watts. If you're trying to disch a 2S lipo starting at 8volts with a 25watt disch limit, the max current you'll see allowed is 25w/8v = 3.1a, this is what you're running into. Chargers limit disch current just like they limit charging current to stay under the charger's power output limit. Reason you don't do it on charger is it is so incredibly slow.


Most chargers are not made to do significant disch (or cycling) due to the heat generated by discharging.

Barritia

I been outside in the cold for over 20 mins thrashing the car around and I can't kill this dam battery. Had to come in as it was too cold. Voltage was still at 14.98volts. I'm well impressed how long these li-po runtimes are with the brushless setups.

Gave up with using the charger to discharge.

Duster_360

iTrader: (21)

Sorry, I forget people live where its cold already...its cold here today...73F.

racer1812

iTrader: (31)

That's fine, didn't know they were new packs. No reason to cycle lipos after that then.

Integra

iTrader: (8)

Do yourself a favor Barritia, When you get some spare $$....Upgrade to a Top level charger. You WONT regret it any time soon.