Is your charger really giving you 4.2 v per cell

[LibertyMKiii]

Thought I would make a thread on this. For bashers I think this is 100% fine, but has handicapped me a bit last year as a speed runners.

I just figured out my charger is only giving me 97-98% of a full charge.

First of all I have a not so great charger and should upgrade. I have a venom 4 channel (4x100 watts).
After buying a cell checker I would notice my voltage had dropped by the time I had the battery in the car. Ends up my charger is off by a small amount.

Example with a Zeee 2s lipo for my sons Slash 2wd.

Venom charger says:

Tenergy cell checker says:

iSDT cell checkers says:

Multi-meter says about the same:

Per cell - It was a 4.17 and dropped to 4.16 as I was connected to it:

 

[Garcbomber]

Does your that charger allow modification of total cell voltage?Tolerances listed?

4.158-4.242 is 1%

 

[Mikeeeeeeeeeeeeeeeal]

How long after you pulled from the charger? I ask since you said it dropped another .01v as you were testing. Is it possible it did reach 4.2v albeit very briefly and immediately they start to drop?

Regardless, pretty disappointed to hear you using that caliber of charger

 

[chris adams]

I have an icharger 6x and it keeps reading the lipo after the charge had finished, and it seems my lipos drop .05 after only a couple minutes from being charged. Not sure if that is a normal thing or not, just found it interesting . If I charge to 4.21 before I make the 30min drive to my spot, the lipos are about 4 2 on the nose when I get there.

 

[LicketySplit]

Thought I would make a thread on this. For bashers I think this is 100% fine, but has handicapped me a bit last year as a speed runners.

I just figured out my charger is only giving me 97-98% of a full charge.

First of all I have a not so great charger and should upgrade. I have a venom 4 channel (4x100 watts).
After buying a cell checker I would notice my voltage had dropped by the time I had the battery in the car. Ends up my charger is off by a small amount.

Example with a Zeee 2s lipo for my sons Slash 2wd.

Venom charger says:
View attachment 274325

Tenergy cell checker says:
View attachment 274326

iSDT cell checkers says:
View attachment 274327

Multi-meter says about the same:
View attachment 274328

Per cell - It was a 4.17 and dropped to 4.16 as I was connected to it:
View attachment 274329

Time to upgrade your charger I’d say. I have the ISDT K4 and a Hota D6+. Both of them are incredible at balancing and accurate. I’ve tested the batteries after charging with a DMM and they are spot on. That being said I still need to get a cell checker, so take my previous comment for what it’s worth.

Also something to note. I still have my Hitec RDX1 Pro. When using a balance board I had similar issues. Replaced the board and it was better, but still not as good as my newer chargers.

 

[LibertyMKiii]

Does your that charger allow modification of total cell voltage?Tolerances listed?

4.158-4.242 is 1%

I wish... I had seen some let you adjust per cell but this one is junk.

How long after you pulled from the charger? I ask since you said it dropped another .01v as you were testing. Is it possible it did reach 4.2v albeit very briefly and immediately they start to drop?

Regardless, pretty disappointed to hear you using that caliber of charger

Only seconds after.
Good news this means I have more speed available in my setups!

I have an icharger 6x and it keeps reading the lipo after the charge had finished, and it seems my lipos drop .05 after only a couple minutes from being charged. Not sure if that is a normal thing or not, just found it interesting . If I charge to 4.21 before I make the 30min drive to my spot, the lipos are about 4 2 on the nose when I get there.

Very normal to see that happen.
I hear the iCharger is the best one to get.

Time to upgrade your charger I’d say. I have the ISDT K4 and a Hota D6+. Both of them are incredible at balancing and accurate. I’ve tested the batteries after charging with a DMM and they are spot on. That being said I still need to get a cell checker, so take my previous comment for what it’s worth.

Also something to note. I still have my Hitec RDX1 Pro. When using a balance board I had similar issues. Replaced the board and it was better, but still not as good as my newer chargers.

Hota was on my short list but the guys with ONYX all swear by iCharger.

At least now I know and can compensate by putting a hair more into it until I get a new charger.

 

[Surchaufeur]

4.19 for me i believe going to report back when i charge my lipos again

 

[RedOctobyr]

I'm happy with my iChargers. I know I can adjust the voltage down from 4.20V, at least, since (for pack-longevity reasons) I have my chargers set to only charge to 4.15V.

If you want to stay closer to 4.20V after charging, either use a lower charge current, or if it allows that, reduce the charge termination current. Like maybe it defaults to stopping when your current drops to 10% of setpoint. Reducing that to 5%, for instance, will let it keep charging longer, putting a little more into the pack, keeping you a bit closer to 4.20V. Or you could do a "normal-current" charge first, and then after it finishes, reduce the set current (say from 5A down to 1A), and run 1 more charge. This will help accomplish something similar, charging until the current drops to maybe 10% of 1A.

There was also a recent discussion of using the trickle charge feature of your charger. That feature, for a LiPo, might also get you a bit closer to 4.20V.

 

[iLikeRCs]

Thought I would make a thread on this. For bashers I think this is 100% fine, but has handicapped me a bit last year as a speed runners.

I just figured out my charger is only giving me 97-98% of a full charge.

First of all I have a not so great charger and should upgrade. I have a venom 4 channel (4x100 watts).
After buying a cell checker I would notice my voltage had dropped by the time I had the battery in the car. Ends up my charger is off by a small amount.

Example with a Zeee 2s lipo for my sons Slash 2wd.

Venom charger says:
View attachment 274325

Tenergy cell checker says:
View attachment 274326

iSDT cell checkers says:
View attachment 274327

Multi-meter says about the same:
View attachment 274328

Per cell - It was a 4.17 and dropped to 4.16 as I was connected to it:
View attachment 274329

What if you set your charger to charge to 4.21v?

 

[Hector_Fisher]

I don't think your charger is "off". Rather, I have noticed alot of the "quality" of the charge depends on two things: 1) the IR of the cells i'm charging, and 2) the tenacity of the charging algorithm,

1) IR cause voltage sag for both discharging and charging (I feel like it should be called voltage lag for charging). For cells with even moderate IR, that means when you apply a charging voltage, the actual cell voltage will lag behind quite a bit. The process is asymptotal, meaning it will approach the 4.2 per cell line, but will take a long time actually getting there. I've observed that the quality of the battery (overall package, like IR, wire size, capacity, etc) greatly influences how quickly the charge proceeds through that asymptote and to actual 4.2 resting.

2) Which leads me to the next point, if the charging algorithm or charger approach 4.2v per cell too quickly, it will detect a full charge, and then shut off. Example; When my b6ac reads 4.2v per cell on batteries, it promptly displays "charge complete" and stops charging. But due to voltage lag/sag, the batteries will again drop back down to some different resting voltage. My hota d6+ has a much better algorithm that continues to trickle charge the batteries longer after "charge complete" and 4.2v per cell is shown (usually 30 minutes or so for charge). I've noticed that depending on the battery, it can then continue trickle charging for up to an hour afterwards for higher IR lipos and usually 10 minutes for high quality, low IR lipos. At which point, the trickle charge is gone and cells now have a resting voltage of 4.2 per cell.

I agree, a good (in your case, different) charger is needed if you want those last few millivolts in the packs. Hota D6+ highly recommended from me. Even with my now higher IR packs, the hota will still achieve 4.2 per cell, it just takes longer (about an hour if your IR is approaching 20mOhms per cell like on some of my older light use packs).

 

[LicketySplit]

I don't think your charger is "off". Rather, I have noticed alot of the "quality" of the charge depends on two things: 1) the IR of the cells i'm charging, and 2) the tenacity of the charging algorithm,

1) IR cause voltage sag for both discharging and charging (I feel like it should be called voltage lag for charging). For cells with even moderate IR, that means when you apply a charging voltage, the actual cell voltage will lag behind quite a bit. The process is asymptotal, meaning it will approach the 4.2 per cell line, but will take a long time actually getting there. I've observed that the quality of the battery (overall package, like IR, wire size, capacity, etc) greatly influences how quickly the charge proceeds through that asymptote and to actual 4.2 resting.

2) Which leads me to the next point, if the charging algorithm or charger approach 4.2v per cell too quickly, it will detect a full charge, and then shut off. Example; When my b6ac reads 4.2v per cell on batteries, it promptly displays "charge complete" and stops charging. But due to voltage lag/sag, the batteries will again drop back down to some different resting voltage. My hota d6+ has a much better algorithm that continues to trickle charge the batteries longer after "charge complete" and 4.2v per cell is shown (usually 30 minutes or so for charge). I've noticed that depending on the battery, it can then continue trickle charging for up to an hour afterwards for higher IR lipos and usually 10 minutes for high quality, low IR lipos. At which point, the trickle charge is gone and cells now have a resting voltage of 4.2 per cell.

I agree, a good (in your case, different) charger is needed if you want those last few millivolts in the packs. Hota D6+ highly recommended from me. Even with my now higher IR packs, the hota will still achieve 4.2 per cell, it just takes longer (about an hour if your IR is approaching 20mOhms per cell on some of my older light duty packs).

That’s exactly why I love the D6+ and now the ISDT K4. After using them I won’t buy another charger that doesn’t continue to balance even after charging is “complete”.

 

[LibertyMKiii]

I'm happy with my iChargers. I know I can adjust the voltage down from 4.20V, at least, since (for pack-longevity reasons) I have my chargers set to only charge to 4.15V.

If you want to stay closer to 4.20V after charging, either use a lower charge current, or if it allows that, reduce the charge termination current. Like maybe it defaults to stopping when your current drops to 10% of setpoint. Reducing that to 5%, for instance, will let it keep charging longer, putting a little more into the pack, keeping you a bit closer to 4.20V. Or you could do a "normal-current" charge first, and then after it finishes, reduce the set current (say from 5A down to 1A), and run 1 more charge. This will help accomplish something similar, charging until the current drops to maybe 10% of 1A.

There was also a recent discussion of using the trickle charge feature of your charger. That feature, for a LiPo, might also get you a bit closer to 4.20V.

Agreed, and sometimes I will stop the charge and restart it to get fully to 4.2. Overall from a speed runner's perspective, I wanted to point out that the reading is off by a little and might be worth checking with some other measuring devices.

What if you set your charger to charge to 4.21v?

This charger does not have that ability, but I can move it to the LiHv setting and watch it closely.

I don't think your charger is "off". Rather, I have noticed alot of the "quality" of the charge depends on two things: 1) the IR of the cells i'm charging, and 2) the tenacity of the charging algorithm,

1) IR cause voltage sag for both discharging and charging (I feel like it should be called voltage lag for charging). For cells with even moderate IR, that means when you apply a charging voltage, the actual cell voltage will lag behind quite a bit. The process is asymptotal, meaning it will approach the 4.2 per cell line, but will take a long time actually getting there. I've observed that the quality of the battery (overall package, like IR, wire size, capacity, etc) greatly influences how quickly the charge proceeds through that asymptote and to actual 4.2 resting.

2) Which leads me to the next point, if the charging algorithm or charger approach 4.2v per cell too quickly, it will detect a full charge, and then shut off. Example; When my b6ac reads 4.2v per cell on batteries, it promptly displays "charge complete" and stops charging. But due to voltage lag/sag, the batteries will again drop back down to some different resting voltage. My hota d6+ has a much better algorithm that continues to trickle charge the batteries longer after "charge complete" and 4.2v per cell is shown (usually 30 minutes or so for charge). I've noticed that depending on the battery, it can then continue trickle charging for up to an hour afterwards for higher IR lipos and usually 10 minutes for high quality, low IR lipos. At which point, the trickle charge is gone and cells now have a resting voltage of 4.2 per cell.

I agree, a good (in your case, different) charger is needed if you want those last few millivolts in the packs. Hota D6+ highly recommended from me. Even with my now higher IR packs, the hota will still achieve 4.2 per cell, it just takes longer (about an hour if your IR is approaching 20mOhms per cell like on some of my older light use packs).

This one will do the same and sit for 1 hr trying to get that last little bit. It is still off by the same amount shown.
Either way, a better charger is on the wish list, but at least for now I can charge to 4.17 or 4.18. Then move it to LiHv and watch it closely to put in that last little bit.

Interesting video from Joshua Bardwell that I had seen when looking into my issue. Even a relatively nice iSDT device was off by a little

 

[Hector_Fisher]

This one will do the same and sit for 1 hr trying to get that last little bit. It is still off by the same amount shown.
Either way, a better charger is on the wish list, but at least for now I can charge to 4.17 or 4.18. Then move it to LiHv and watch it closely to put in that last little bit.

Interesting video from Joshua Bardwell that I had seen when looking into my issue. Even a relatively nice iSDT device was off by a little

Interesting. So to clarify, do lipos charge to 4.2 on the venom and then drop back down after? Or does the charger read 4.2v but all your other instruments read lower?

 

[LibertyMKiii]

Interesting. So to clarify, do lipos charge to 4.2 on the venom and then drop back down after? Or does the charger read 4.2v but all your other instruments read lower?

venom says 4.2 but 3 other devices show lower. Readings were taken seconds after pulling off the charger.
This model venom has 4 fully independent channels (I read somewhere even 4 separate power supplies) but all 4 are mis calibrated. I have to assume they decide to err on the side of caution and made it read a bit high to slightly undercharge lipos.

 

[RedOctobyr]

This charger does not have that ability, but I can move it to the LiHv setting and watch it closely.

Are you certain it doesn't allow tweaking voltages? Some stuff in the manual implies that maybe that's possible, like on page 7? They're showing a voltage and referencing the change buttons, but maybe that's to change the lithium type.

https://www.spektrumrc.com/on/deman...zon-master/default/Manuals/VNR0685_Manual.pdf

(edit: oops, sorry, maybe this is the wrong manual, if yours is 4 channels)

That's cool it can do LiHV, at least. Though personally, I would not be comfortable using that setting. Stuff happens, people get interrupted, and now you're deliberately overcharging a LiPo. I would much rather use a long, slow standard charge cycle, if it were me.

The interface looks a lot like my ICharger 106B+, but sadly does not mention some of the customization options that mine provides. That's too bad, since some of those could help achieve what you're trying to do.

 

[Hector_Fisher]

venom says 4.2 but 3 other devices show lower. Readings were taken seconds after pulling off the charger.
This model venom has 4 fully independent channels (I read somewhere even 4 separate power supplies) but all 4 are mis calibrated. I have to assume they decide to err on the side of caution and made it read a bit high to slightly undercharge lipos.

Ah, yes then it sounds like you are right about the calibration issues.

I agree with the thought process you applied in your OP, in that if multiple of your independent means of measuring battery voltage agree, but one doesn't, then it's probably an issue with the outlier.

 

[KnowAir]

No techie myself but I did notice my Hota S6 will continue to push voltage into the cells as needed to maintain 4.2v per cell for as long as the batteries are connected to the charger.
How accurate the S6 is, IDK. Some may have read the debate I had with another member on the forum about the S6 and the "trickle" charge..
I still maintain my view on that topic, there's just no way this charger will in fact "over charge" a pack by any concerning amount unless something goes wrong. Which of course is always a possibility. Hence the rule of never leaving things unattended.

 

[Hector_Fisher]

No techie myself but I did notice my Hota S6 will continue to push voltage into the cells as needed to maintain 4.2v per cell for as long as the batteries are connected to the charger.
How accurate the S6 is, IDK. Some may have read the debate I had with another member on the forum about the S6 and the "trickle" charge..
I still maintain my view on that topic, there's just no way this charger will in fact "over charge" a pack by any concerning amount unless something goes wrong. Which of course is always a possibility. Hence the rule of never leaving things unattended.

Physics-wise, as long as the output voltage of the charger to the pack while charging doesn't exceed 4.2 times the number of cells in your pack (ie, for a 4s pack, 4.2 x 4 = 16.8v total), and as long as the charger's balance function is acting normal (and not going haywire), then there is no possible way to exceed 4.2 per cell during a lipo balance charge, even during the "trickle charging" portion of the charge cycle. Electricity equalizes like water pressure. If your max output voltage is 16.8v, then eventually the lipo will also reach 16.8v, if it's connected to that 16.8v source.

Doesn't mean the lipo can't spontaneously become volatile, that can happen at any voltage. But it wouldn't be due to a normally operating balance charge.

 

[KnowAir]

Physics-wise, as long as the output voltage of the charger to the pack while charging doesn't exceed 4.2 times the number of cells in your pack (ie, for a 4s pack, 4.2 x 4 = 16.8v total), and as long as the charger's balance function is acting normal (and not going haywire), then there is no possible way to exceed 4.2 per cell during a lipo balance charge, even during the "trickle charging" portion of the charge cycle. Electricity equalizes like water pressure. If your max output voltage is 16.8v, then eventually the lipo will also reach 16.8v, if it's connected to that 16.8v source.

Doesn't mean the lipo can't spontaneously become volatile, that can happen at any voltage. But it wouldn't be due to a normally operating balance charge.

I don't want to derail the thread by any means. I understand what you're saying, perhaps I didn't properly explain it. I know the charge rate ramps down as a pack nears completion, what I was referring to is, after the charger is done, cycle complete, the charger will continue to moniter cell voltages and keep pushing (or pulling)current to maintain peak voltage of 4.2, or whatever you've set it for, for as long as the pack is connected. Even though the cycle has finished.
This may be common amongst "good" chargers, IDK, this is my first quality charger. I do like the Hota S6 so far.

 

[Hector_Fisher]

I don't want to derail the thread by any means. I understand what you're saying, perhaps I didn't properly explain it. I know the charge rate ramps down as a pack nears completion, what I was referring to is, after the charger is done, cycle complete, the charger will continue to moniter cell voltages and keep pushing (or pulling)current to maintain peak voltage of 4.2, or whatever you've set it for, for as long as the pack is connected. Even though the cycle has finished.
This may be common amongst "good" chargers, IDK, this is my first quality charger. I do like the Hota S6 so far.

Perhaps I wasn't being clear as well. I agree with you. I was trying to support your argument that the "trickle charging" portion is nothing to be concerned about since voltage won't/can't be exceeded on the pack. I think we're on the same page