Speaking of Li-Pos - Is there such a thing as a good DIScharger for them? Thanks.

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cvanc

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Hey troops-

So I'm digging this new charger George Gassaway posted about ( https://www.rocketryforum.com/showt...harger-for-four-3-7V-LiPo-batteries-thumbs-up ). I'll probably pick one up soon.

But it occurs to me that to fully know the health of a cell it would have to be discharged to some appropriate reference level before you charged it back up. Georges' little charger will (apparently) tell you exactly how many mAh's went into the cell during charge, which is pretty sweet. But I don't think it does any discharging.

Does such a thing as a 'discharger' exist? Or, have any of you made something to do the task? Thanks!
 
I have this unit https://www.thunderpowerrc.com/Prod...-10-0-AMP-AC-DC-CHARGER-DISCHARGER-W-BALANCER.

No offense to the cheap and cheerful "got a deal" camp but I don't believe cheap and cheerful is the right way to go with these chargers. I have gone that route may times in the past and it has just cost me more in replacing batteries, poor run times and letting me down when I needed it the most.

If you can afford a decent charger it may be worth your while, especially if you're into any RC. There are other manufacturers but this one is US and their customer service is absolutely fantastic. I purchased four 1S Li-Pos and one was defective and they sent me four brand new ones on their dime, no questions including shipping from them in California to me in Ontario.

Here is a video review on the product

[video=youtube;YNTL8-y0hYs]https://www.youtube.com/watch?v=YNTL8-y0hYs[/video]
 
https://www.amazon.com/dp/B00KPM4GL2/?tag=skimlinks_replacement-20
This one doesn't do a batch of Lipos, but it does EVERYTHING. 1s-6s Lipos, Li-on, Li-Fe, 1-15 cell NiCD, NiMH and Lead Acid (Pb). It'll charge, fast charge, discharge, storage charge/discharge, and balance. Note: you will need to buy an AC adapter and maybe a battery side adapter. Mine came with 2 sets of alligator clips, one to run off of a 12v battery, the other for the charging side, a Deans connector (which can be cut in half and used as a Traxxas connector), a JST connector, a Futaba receiver connector, and a glow plug connector.
 
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I have this unit https://www.thunderpowerrc.com/Prod...-10-0-AMP-AC-DC-CHARGER-DISCHARGER-W-BALANCER.

No offense to the cheap and cheerful "got a deal" camp but I don't believe cheap and cheerful is the right way to go with these chargers. I have gone that route may times in the past and it has just cost me more in replacing batteries, poor run times and letting me down when I needed it the most.

If you can afford a decent charger it may be worth your while, especially if you're into any RC. There are other manufacturers but this one is US and their customer service is absolutely fantastic. I purchased four 1S Li-Pos and one was defective and they sent me four brand new ones on their dime, no questions including shipping from them in California to me in Ontario.

Here is a video review on the product

[video=youtube;YNTL8-y0hYs]https://www.youtube.com/watch?v=YNTL8-y0hYs[/video]

hahahahah...
Why does this not surprise me in the least.....
Michael P..... you da man............
Thunder Power 610C has been my charger for years...
Great charger...
Charge,, balance,, discharge,, even cycle to your specification both on the top side and on the bottom...........
And any battery chemistry.......
The only problem is it does lipo's from 2s through 6s.......
So for all of the 1s lipos I had to bring them in the house and charge them off of a USB port on my computer...
I bought a charger,,, 1s through 6s lipo,, charge,, discharge,, balance ( except 1s of course ) and cycle-----
4 times,,,, it has 4 separate 100 watt ports,,, it'll do 4 batteries at the same time any chemistry,, any mix of them.....
No more waiting,,, no more going into the house for a USB port............

Very cool as I use a lot of batteries,,, altimeters ,, BRB beacons,, GPS Eggfinders............

Very cool,,,
I'm very happy with it...

Oh--- and I don't have to plug it into my 12v power supply,, it has it's own built in,, it plugs into 110V....

Teddy
 
The Thunder Power, just like the SkyRC, will do 1s lipos. You plug them directly into the main charge port, rather than the balance board. SkyRC also has an AC model Called the B6AC. There's a lot of similarities between the two, including the interface. I've been using the SkyRC one for a while now, with Lipos and Lead-Acid. It's worked well for what I need it for. I wouldn't hesitate to buy either.
 
hahahahah...Why does this not surprise me in the least.....Teddy

Teddy it's like we were separated at birth :D

The only problem is it does lipo's from 2s through 6s.......Teddy

As Tonimus pointed out it sure does charge 1S, just no balancer required as it should only have the JST connector to plug into the charging leads with the banana plugs.

So for all of the 1s lipos I had to bring them in the house and charge them off of a USB port on my computer...Teddy

:facepalm:
 
No wayyyy,,,
Come on,, I'm not that bad,,,,lol...
My 610 C I bought at the RC event "Top Gun" in Florida years ago...
They just came out with it..
They still didn't offer one with a built in power supply,,
You have to feed mine 12 V. DC...
On my new 4 port charger to do a 1s you take it out of "Balance" mode...
My 610 C when in Lipo mode only has "Balance Charge",, Discharge,, or Cycle...
There is no way to take it out of Balance mode...

That's too funny,,,
You guy's thought you had me ehhhhh.................lol......

Teddy
 
Hey Tony,,
Don't hang around with that Michael Pit guy,,,
he's a bad influence.....lol.....
He'll have you picken on me in no time for sure....lol....


Teddy
 
They still didn't offer one with a built in power supply,Teddy

Right off the "product Description":

"The Thunder Power RC TP610C-ACDC charger is the long-anticipated and fully integrated AC/DC version of the popular TP610C. The built-in AC power supply allows the charger to be easily and conveniently powered from a 100-240V outlet while the included DC input power leads can be connected to 12V lead-acid/gel cell batteries for charging at the flying field or outdoor track."


Teddy, you need a new one.
 
Yeah,,
Maybe the newer 610C's will do a 1s..
That's very likely as it should have been a fairly easy change..
But when Thunder Power first came out with it it didn't..
Mine does from 2s through 6s...

You ain't hookin me on this Pit.......lol.......

I'm goin to bed ,,,
gnite Michael....

Teddy
 
Hey Tony,,
Don't hang around with that Michael Pit guy,,,
he's a bad influence.....lol.....
He'll have you picken on me in no time for sure....lol....


Teddy

For some reason, I think it's a bad idea to pick on the guy who makes something that brings my rocket back in one piece...

Also, under Lipo balance, does it have a 1s setting? They might not have a separate menu just for 1s stuff.
 
SkyRC IMax B6 mini is my tool for this job. 1 thru 6 Cell Balancing Charger /Discharger. I like the 'storage' setting, I have had quite a few LiPo's bubble on me. Not one of the new ones that I charge with this has done it yet, been using the storage mode after each weekends use.
 
Tony,,
My 610C doesn't go below 2s in the menu...
And after you get to Lipo from all of the battery chemistry options there is Balance,, discharge ,, or cycle....
On the new 4 port charger I bought there is an option called "Charge" and that is how you access 1s.....
I'm tellin you guy's it won't do it... If it did I may not have bought another charger...
But the bang for the buck is tough to pass up today...
When I bought my 610C it was 5 times the money that they cost today...


Bob Krech,,
As usual,,,
You hit the nail on the head...
That line voltage B6 is the charger I was drooling over...
It'll do pretty much anything...
The reason I did'nt go for it is it's a single charger
and I find myself charging many batteries now...
Many more then when I flew RC...
The charger I bought is very similar to the B6 but it is a 4 port charger.....
It'll do anything to 4 batteries at the same time...

Teddy
 
That's a super charger Random,,,
That's very similar to the 4 channel I bought..
But mine is 100 w per channel
and I think yours id rated better for reliability...
Mine was a lot less money..
I figured if it's going to work ,, then it'll be fine..
And if it's not I'd hope it'd show the fault right away and I'd just send it back for an exchange...

Plus,, I already had the power supply on my bench so the one I bought doesn't have a built in one...
You must feed mine 12 V DC...

Teddy
 
That's a super charger Random,,,
That's very similar to the 4 channel I bought..
But mine is 100 w per channel
and I think yours id rated better for reliability...
Mine was a lot less money..
I figured if it's going to work ,, then it'll be fine..
And if it's not I'd hope it'd show the fault right away and I'd just send it back for an exchange...

Plus,, I already had the power supply on my bench so the one I bought doesn't have a built in one...
You must feed mine 12 V DC...

Teddy

I feed mine 120VAC when I am at home and 12VDC while in the field. Stuffed the charger, cables and a sealed lead acid in to a pelican case. The combination works very well. Some of my AV bays have four separate LiPo packs so having four charging channels fits my application perfectly. I have used the charger in the outside summer heat of Texas and Kansas with no problem at all. I highly recommend it.


Sent from my iPhone using Rocketry Forum
 
I feed mine 120VAC when I am at home and 12VDC while in the field. Stuffed the charger, cables and a sealed lead acid in to a pelican case. The combination works very well. Some of my AV bays have four separate LiPo packs so having four charging channels fits my application perfectly. I have used the charger in the outside summer heat of Texas and Kansas with no problem at all. I highly recommend it.


Sent from my iPhone using Rocketry Forum

I've been lovin the one I bought as well...
Same application too,,,
If the av bay is redundant there are 2 lipo's in it...
In my nose cone there is a ham base tracker and a GPS based tracker..
That's 4 lipo's to charge...

Teddy
 
https://www.amazon.com/dp/B00KPM4GL2/?tag=skimlinks_replacement-20
This one doesn't do a batch of Lipos, but it does EVERYTHING. 1s-6s Lipos, Li-on, Li-Fe, 1-15 cell NiCD, NiMH and Lead Acid (Pb). It'll charge, fast charge, discharge, storage charge/discharge, and balance. Note: you will need to buy an AC adapter and maybe a battery side adapter. Mine came with 2 sets of alligator clips, one to run off of a 12v battery, the other for the charging side, a Deans connector (which can be cut in half and used as a Traxxas connector), a JST connector, a Futaba receiver connector, and a glow plug connector.
That looks like a Turnigy Accucell clone. Here's a large variety of popular and low cost Turnigy chargers from the Hobbyking US east and west warehouses:

https://www.hobbyking.com/hobbyking...y=&sortBy=Relevant&NumPerPage=20&currentPage=

https://www.hobbyking.com/hobbyking...y=&sortBy=Relevant&NumPerPage=20&currentPage=
 
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But it occurs to me that to fully know the health of a cell it would have to be discharged to some appropriate reference level before you charged it back up. Georges' little charger will (apparently) tell you exactly how many mAh's went into the cell during charge, which is pretty sweet. But I don't think it does any discharging.

Does such a thing as a 'discharger' exist? Or, have any of you made something to do the task? Thanks!

I just ran across this thread.

For most of the cases where I'm keeping good track of battery capacity, it is when the batteries are used with an electric plane or multicopter that uses one or more ESC's that shut the throttle off (or lowers throttle in case of small Quads), when the voltage has dropped to a certain level.

But that does not do you any good.

However, I can recommend another great little inexpensive device.

A Lipo Battery tester. Do an Ebay search for these keywords:

rc lipo battery tester alarm

Looks like this:
71sldRCPzRL._SX355_.jpg


Leftmost pin is negative/ground, 2nd pin is +V for Cell #1+, 3rd pin is +V for Cell #2+, etc.

It displays the total voltage, then the voltage for each cell, up to 8 cells. For what you are doing….. you'd only use the left pin for ground and 2nd pin for the +V from the single LiPo battery. Of course you'll also need to wire up a connector adapter for the little "stick" Lipo's

Now, it is not a discharger, in the sense of the fancy big chargers. But, it can be set to sound off a very loud alarm when the voltage drops to a pre-set level, such as 3.3V. So, you could plug the battery into some load and just be sure you'll be around to hear it when it sounds the alarm (the alarm is so loud you might want to muffle it. Or turn the loudness into a feature by doing the test in the workshop if you might be able to hear it in other parts of the house). What you don't want to do is to get so far away that you never hear it go off, then when you come back, the LiPo is dead, and as you probably know when a Lipo goes below 2.7V it starts to chemically break down, under say a volt and it's ruined dead-dead. So, that is one thing that the big brother chargers can do, a discharge to certain level then STOP automatically, even beginning a recharge cycle.

Of course, the old school glowing red LED display will draw some current by itself. For more current you could use say a small old-school incandescent 4 to 4.5 volt flashlight type bulb, since it lights up. But given the LED display, you could use most anything else that would be suitable, perhaps use a 500 ohm (or 100 ohm?) potentiometer and dial it down to get the desired current level.

Anyway, I really like that little unit…. and have several. Right now, one is double sided servo-taped to a multicopter as an inflight battery monitor. So, I'll hear it beeping long before the voltage gets too low to cause a crash (can hear it easily from a hundred yards away, like I said it is loud!).

Here's a Youtube video of it in use with a 2 cell LiPo battery, many similar vids out there but this one is short and to the point.

UPDATE - see message #24 for a better video of the tester/alarm

[video=youtube;tupNpOKHxJw]https://www.youtube.com/watch?v=tupNpOKHxJw[/video]

A pic showing 6 images of it in use with a 3-cell Lipo, note the 4 wires starting at left
1.0x0.jpg



Now, having said all the above……the HiTec 4X Charger I recommended was for the convenience of charging a lot of those little 3.7 V batteries, up to 4 at a time.

If you do not need to charge several very much, and DO want to be able to test capacity by doing automatic discharging, then you could consider this IMAX B6 charger that is a lot cheaper than the HiTec 4X. There was a thread on this a week or two back where ironically the guy asking how to charge a small Lipo battery (70-100 mAh) decided not to use a LiPo after all. But this is a "big charger", it simply does not charge more than one battery. And you can use it for lots of other batteries, maybe not right now but probably eventually.

Anyway, Hobby King has it ($25), but so do others on eBay for cheaper (but longer wait times from China).

Edit - I see Bob Krech also recommended it. He linked to the version that can run off of 120 VAC (as well as 12 VDC), which is definitely useful if you do not have a 12 power supply to run off of at home. Although until I got a "real" 12V power supply, I used to run field 12 V powered RC battery chargers by using a 12V battery with a 12V charger hooked up to keep the source 12V battery charged up. Worked OK for charging small batteries, since those plus their charger did not require more current in total than the charger (plugged into 120 VAC) was producing to keep the 12V battery topped off.

https://www.hobbyking.com/hobbyking...5A_Charger_Discharger_1_6_Cells_GENUINE_.html

imaxb6.jpg
 
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Purchased my IMAX B6 charger 6 or 7 years ago and use it regularly with my electrics...I forget where I purchased it from and what I paid for it---believe it was less than $50.00, maybe a little more...The unit I have came with an aluminum metal case and several different adapters...Not sure if the unit Hobby King is offering comes with a case,,, However, I am satisfied with the charger and have experienced no problems with my unit...I use my unit primarily to charge 3, 4, and 5 cell LiPo batteries...I feed the charger from two Lawn tractor batteries hooked up in parallel that are kept charged with a trickle charger that I disconnect when charging LiPo batteries...
 
I've had a Hyperion EOS 0615i DUO3 for years. It will charge/discharge/cycle 1S-6S lipos. I have a 700w server power supply that I use to run it on AC.
 
BTW - Here is a video I made 3 years ago to show someone who had borrowed a "Venom" charger (for single battery packs , not four) how to adjust it to charge 100 to 150 mAh 2 cell Lipos.

I used a Hobby King Quattro charger which can charge four batteries. But the programming seems to be the same as for most of the single and quad chargers out there that use the same sort of LCD display and 4 buttons. I did not get into the extra features such as discharging or cycling, only wanted to show him what he needed to know to get the Venom charger to charge the 2 cell LiPo. Most likely the B6 charger is similar in operation.

[video=youtube;yQPRr24X328]https://www.youtube.com/watch?v=yQPRr24X328[/video]

BTW - Here is a much better video of the Battery tester/alarm:

[video=youtube;JryMOh2Ek7A]https://www.youtube.com/watch?v=JryMOh2Ek7A[/video]
 
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Thanks everybody for the conversation. I think I'll make something for myself and see how it works. I'm thinking a 3.9V 5W Zener diode in series with a 1/2 ohm resistor. This should discharge a 1S cell down to 3.9V and "just stop on its' own". There should be no need to be there to disconnect it at a certain moment.
 
Zeners are generally sloppy, it will still draw current below the designated voltage as well, just not as much. In a circuit I built years ago it took a 3.6V zener (MMBZ5227B) to pull a 3.3V rail down to 2.4V (through a 332Ω resistor, they do get sloppier as the current decreases, I was trying not to burn much power in this circuit). So be sure to keep an eye on the cell voltage to not discharge it too much, and you may need to play with different zener values.

That meter would seem to be fine for a 1s battery because presumably its powering itself from the battery. But on a "N"s (N>1) battery I suspect it's powering itself from one of the taps (either the first one or the one that provides the highest voltage) and probably only sensing the rest, i.e. pulling very little power from the other cells. So I'd be surprised if it discharged them evenly. I think you'd need a balancing charger/discharger for that. I've been meaning to hit my local RC hobby shop and see what they carry in terms of a storage charger since I'd rather not order it from online (especially if it has to ship from overseas).
 
That meter would seem to be fine for a 1s battery because presumably its powering itself from the battery. But on a "N"s (N>1) battery I suspect it's powering itself from one of the taps (either the first one or the one that provides the highest voltage) and probably only sensing the rest, i.e. pulling very little power from the other cells. So I'd be surprised if it discharged them evenly. I think you'd need a balancing charger/discharger for that. I've been meaning to hit my local RC hobby shop and see what they carry in terms of a storage charger since I'd rather not order it from online (especially if it has to ship from overseas).

It probably is powering itself from the highest voltage (therefore all cells), then cycling thru the voltage taps to report on the individual voltage levels. In the case of what cvanc wants to do for a single LiPo cell, there would not be an uneven discharge issue.

Realize however that in real use with packs of 2 or more cells in series, the cells are not being discharged evenly anyway. Well, in theory they are, but only if the cells are performing exactly (100.000%) the same to each other. The "balance connector" normally used only for charging to help monitor and balance during charging, isn't hooked up unless it is being used to monitor the voltage of the cells during use. But it's not being used to say cause more power to be taken from the higher voltage cells to give some relief to a weaker cell. Now in a very sophisticated system (like an electric car or perhaps laptop battery) I could see that might be practical, but not for hobbyist R/C-oriented batteries and equipment.

So I really think it would be better for a discharger to not try to balance the cell voltage during discharge, LET them get out of whack, because if you have a pack that has a weak cell you will be able to notice that once you see the voltage of each cell after discharge or shortly after beginning recharge. A discharger that left the cells all at about the same voltage, due to its uneven discharge per cell, would mask the problems.

For the small 2 cell (7.4V) battery packs we use a lot for contest-type R/C Rocket Boosted Gliders, with capacities of 70 to 150 mAh, we do not even use balance connectors. The size and mass of the connector is not justifiable. If a 2S pack capacity starts to go down over time, which may be due to cell imbalance, the pack is "retired" from use in gliders, then only used for electric models with ESC's that will shut off the throttle and allow a safe landing when the voltage gets too low.

- George Gassaway
 
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Look into the FMA Cellpro 4. Won't be disappointed.

I had one if these in the past. It's a great charger. The only reason I got rid of it was I needed a charger that could handle more cells and amps.
 
Thanks everybody for the conversation. I think I'll make something for myself and see how it works. I'm thinking a 3.9V 5W Zener diode in series with a 1/2 ohm resistor. This should discharge a 1S cell down to 3.9V and "just stop on its' own". There should be no need to be there to disconnect it at a certain moment.
3.9 volts is not a discharged battery, indeed it's almost fully charged. One would normally discharge a LiPo to 3.0 volts. (Any lower than 3.0 volts will damage the battery and shorten the cycle life.) https://learn.sparkfun.com/tutorials/battery-technologies

The absolute charge voltage limit for a LiPo cell is 4.2 volts. Any higher and you will damage the battery permanently and shorten the cycle life and reduce the capacity. A fully charged LiPo cell will self-discharge to 3.9-4.0 volts in several days and stay there. It will rapidly drop to 3.7 volts under load (90% capacity) and gradually drop to 3.4 volts with about 10% capacity remaining. It will fall off a cliff and should be shut off before the cell voltage drops to 3.0 volts or permanent damage will occur.

I would not be surprised if in a hybrid car, the LiPo cell voltage swing is limited to between 3.6V to 3.5V (44% C) to 3.7V to 3.4V (82% C) swings to maximize battery cycle lifetime. All hybrid cars using NiMH cells limit the capacity swing to 60% to obtain a nearly limitless (many thousand) cycle lifetime.

Bob
 
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