This video inspired me to make my own discharger. Used a $12 foglight kit from Walmart. Came with a switch and everything. Best part the bulbs are in nice housings that contain the extreme heat.
Thanks Joshua. I wonder if this might work for one of my batteries as my charger doesn't have a discharge setting. It's a Multistart 3S 4000 10C batt. I've been getting about 15mins on my 500 quad before my Naza warning light comes out which I've set to 10.5 for first warning. It's been taking almost 4000(a lot I know) on charge but never measures lower than 11.1 when I land. Yesterday warning light came on at 7 mins, so landed and after battery cooled charged(5A) it but only too 1500mah. Seems slightly puffed but not much. Today same deal so charging it at 1.5A then I'll see what happens. Planning on getting another charger that will discharge but perhaps it's something else. Doesn't appear to be over discharge of course at 11.1 at landing but I'm not sure. Any feedback would be appreciated, Thanks
I just got some heat syncs and fans from computers for general heat management and will use some of this info for discharging. Thanks. For fun, I am thinking an EDF connected to a vacuum canister so battery drainage is shop cleanage. Or something like a leaf blower just to clear the space.
Hey JB, Im sure you get more questions than you can handle. I think that one of my setups is messing with my batteries. I just started building my own quads. I am flying with 3s 2200 mah 25C batteries. (Its all I had on the shelf from my walkera runner) I think that my batteries are getting over-discharged or discharging too rapidly. I have the failsafe on at 3.5v in cleanflight and I rarely go that far. I have a couple new batteries coming in the mail, and I would like to fix this problem before I ruin all of them. After flying, my batteries are really hot and some have become puffy. I think that my setup is discharging the batteries too fast. Feels like I am using the wrong batteries. What is the best way to measure the true power requirements of a quad? This might be a neat little topic because I cant find much info aside from a formula to calculate flight time. I want to include all vehicle systems; vtx, tx, led strip, etc. Ideally, I would like to see measurements during flight. I think that this might help select the correct battery. I havent played with blackbox much, so I apologize if I am missing the obvious answer. Thanks for everything that you do for the community! I wouldnt be flying without you.
I need a cheap way to discharge my escooter's 48v Lifepo4 and my ebike's 52v lipo battery. Both have XLR connectors. The 52v lipo has an led on/off switch which I often leave on as a parasitic drain, but since it takes so long to drain down to 50%soc, I sometimes forget and I afraid I will accidentally drain it fully. The 48v is Chinese and is from 2016, so I really need to pay attention to that one over the winter or it may be anemic come spring. I don't use it that often throughout the year, so it has relatively few cycles. I just need a cheap way to make a light bulb glow, but I don't have the skill to make it. Any help is appreciated.
Would this method work for storage charging? Eg, a full battery you want to storage voltage, add in this patch and bulb and then actively switch it off when the charger says you are at the correct voltage?
Thank you for this video. Do you think this will work with the ISDT T8 charger. I like the idea of a faster discharge. It rained today and I had to discharge my second set of 6000mah batteries. It took me a while
Great info! could i use this when I'm breaking in new lipos? tired of hovering for ages with the quad.. I have sometimes got a little to heavy on the throttle on new lipos when i get bored. also how many cycles do you do before full throttle?
+2663540 I don't break in my batteries. I'm not convinced there is actually a reason to break in LiPos. But you could use this to break them in if you wanted to.
I got the halogen bulb as suggested and set it up exactly how you did but when I'm trying to discharge a fully charged lipo the halogen bulb lights up for about 5 seconds and ramps up the amps but then it drops right back down to 1amp and the bulb goes off! Why would it do that? It's taking me hours to discharge my unused lipos after a flying day :-(
From the thumbnail it looked like you had soldered your wrench straight to the wires. It seemed like a brilliant idea to me. I was disappointed that your method was much safer. I think using the wrench as a resistor would be faster, though.
@Joshua -- you really shouldn't suggest people use alligator leads for this. You may have leads that can handle 10A, but a substantial number of them cannot. They often use 22awg (or smaller) wire, with weak crimps onto the clips themselves. Pulling any amount of current for more than a few seconds will cause the insulation to melt and may start a fire. The loopback XT60 is a much better idea -- bonus points if you solder a 40A blade fuse directly across an XT60 to safeguard against blowing a battery up on accident.
Joshua what do you think about re releasing this video? I think many experienced hobbyists funny know this exists still. Maybe only cover the charger's "discharge plus" feature?
Hello Joshua, thank you for sharing your thouhgs and videos. I have a issue with the same kind of charger (mine is reaktor 300W 20A AD/DC from HK), I made light bulb (12v 21W) chain of 12 bulbs in total in which 2 connected in series and 6 (those 2 series connection) in parallel, which gave me in total 24V 252W. I connected it in load (positive lead of battery to positive lead of bulb chain and negative lead of bulb chain to negative lead of charger, and negative lead battery to negative lead of charger. As you did, same thing DSC+ mode, select 10A and 3.4V, press and hold start button, it start going up to 9.9~10Amps for a 5~9 seconds (bulbs turned on), after that it slightly fall down untill 0.89Amp. Battery is fully charged 6S 10000mAh. I made all settings in reaktor menu for limiting current and voltage but it hopeless, may be you can help with it.
+PiManASM Yes. It wouldn't be too hard. I could imagine a voltage divider feeding pack voltage into the gate pin of a FET. Use a potentiometer as part of the divider and then adjusting it would adjust the voltage at which the FET turned off.
Nice vid. been wanting to know how that all worked. be cool to see one with car battery. how to the discharge. could it be done while powering the charger from the same car batt it's using to discharge I wonder? could be usefull
Joshua, I've got your own parallel board V2. Assuming that each battery's voltage are within 0.4v of each other, can I use it to discharge lipos to storage voltage? Also, can I mix 1300 with 1500mah lipos? Thanks in advance.
Very insightful video, thanks for the tips. On a side note, how are you liking the Turnigy Reaktor Quadkore? Any comment to let's say the iCharger 300watt?
+Joe Hannouch Well, I've never used an iCharger so I couldn't say. It's nice having 4x 300 watt chargers though. Really easy to slap four batteries on regardless of state of charge, or get a bunch of parallel charge boards going. I can charge 11x 1300 mAh 4S in about a half hour, with capacity to spare.
I have a standard household 100W light bulb and am discharging 4x4 18650's wired to run at about 14.8V. they re simply running the light bulb as normal, and the element just barely glows. It's working but at this rate it will take way too long to discharge fast, the whole idea of doing this. If I do the dead short as you have, using the same household bulb, will that make a difference in discharge speed? Or will I be essentually doing the same thing as I am? Please forgive the question if it's stupid, I know little about the math on this stuff :)
Hi Joshua, thanks for the video. I built a device with two 50w halogen bulbs in parallel wired in series in the positive lead just like you did. I am using the Reaktor 2x300w and i get the same effect you had here, the discharge current goes up to what i set and shortly after drops down to the charger's rated maximum internal discharge rate of 1.3a (=20w). In the Reaktor manual it says in DSCH+ mode it will discharge with up to 150w for about 30s. So my question is, how do i get it to discharge continuously at the set amp without dropping back to 1.3a discharge rate after 20-30 seconds? Shorting out my light bulbs with a 4s pack gave me about 8,5 amps on my amp meter to work with. I used fully charged 4s for testing with the reaktor.
+Flo Sch I also observed this with the Reaktor and I have no idea why it's happening. The light bulb should be dropping voltage and dissipating heat. The internal resistors should not be taking any load. The reason the unit drops to 1 amp is that the thermal overload is kicking in, but I have no idea why that's happening.
Flo Sch Well done. That's obviously the issue. Sounds like a real flaw in the design of the charger. What a shame. But wow, at least the charger has protective circuitry to keep itself safe during this condition.
Sorry, I know this is a slightly old video, but as with a lot of your videos, it still feels relevant! Thanks for keeping these up there. I was just wondering if there was any reason why you wouldn't just use a couple of power resistors in series on the positive line? maybe 200W so with a 2s from 8.4v you'll discharge at almost 24A....or is that too fast?
If you had a 2S battery and wanted to discharge 200 watts you would need a 0.33 ohm resistor and would discharge 24 amps. The amps is probably safe for most 2S packs down to at least 1000 mAh and probably smaller, however the voltage sag at that high output would probably make stopping at a precise voltage difficult. For more: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4CVd7QjGKGE.html&ab_channel=JoshuaBardwell
@@JoshuaBardwell Thanks for the link....the load bank looks like a fun build, if only for the knife switch! Although every time I switch it I'll have to give an insane monologue and a manic laugh MMWAHAHAHAHA!
I read the title of this video and got so excited about the possibilities... of what the content could. I was disappointed... ( I am also a NASCAR fan and like watching cars crash ) -- as always .. great information.
No, because the bulb's resistance is designed for 220V so the current flow at 12v will be basically zero. On a side note, why do we tend to use a capital 'v' when writing mains power (220V) but a little 'v' when writing low-voltage DC (12v)?
+Jason Stapels I looked into using resistors, and what I found was that the big load resistors all needed heat sinks to reach their rated wattage. I don't really know what the effect would be of running it without a heat sink, but I know you can run a light bulb without a heat sink, so that's the direction I went.
great video but quick question. i had a 3S fully charged up (4.2 per cell). But i crashed the plane, it is going to take me a while to rebuild the plane.....Each cell was still at 4.13, . Should i discharge the 3S down to 3.85 or should i discharge it down to 3.2 or something? (with my balance charger that has a discharge feature). then bring it back up to 3.85 ? (with my balance charger). I will not use it again until my plane is fixed. Probably a week or so.
@@JoshuaBardwell Excellent. Last thing...sounds like you have tons of experience / flight-time. What battery brand have you had the most success with? Turnigy or something else? I want to go with what someone like yourself would recommend. thx in advance .........
Might want to make sure your bulb leads are insolated from each other. They are not heavy duty silicone. The copper wire itself can take the amperage all day, but the insulation may get hot and melt and if the 2 leads touch we get a good example of why we never short a battery. Your 100 watt bulb circuit will become 0 ohms. I know the charger will limit the discharge current, but we don't want a bench fire.
+Invitingsauce Charge in NiMh mode at like 0.1 amps until the battery hits 3.2 volts per cell. Then charge as normal at like 0.5C. DO THIS IN A FIREPROOF LOCATION. I have never had a problem before but you never know.
Josh the problem I see with discharging at such a hi Amp draw say 7 amps is the battery recovers quickly and your storage voltage may end up being 3.95 .... maybe that is why most chargers only discharge by 1 amp etc
The chargers discharge at only 1 amp because the resistor banks they use as a load can only take so much heat. Discharging at high load will result in more rebound, it's true. This can be dealt with if desired.
Yes I Suppose ....Be great if the smart charger/discharger were exactly that and ramped down there discharge current towards the end to give a true end voltage that you preset....more automation maybe needed , Ive yet to see a smart discharger that can work correctly. Have a look at your end cell voltage if set to 4s pack and 3volt (li-ion) per cell discharge, mine ended up 2.8 + 2.9 + 3.0+ 3.1 hardly and true balance discharge
In your smoke stopper you only use one bulb? You haven't blown any using a 4s battery? I'm about to wire one of those up and was going to use two bulbs in series but if I can get away with only one that would be nice. The bulbs are rated at 12.8-14V... Seems like a nice little gadget to have for the bench.
How to turn your daughter's Easy Bake Oven into an Easy Bake Microwave. Just change the bulb. LOL Just a note...read the comments before he connects the bulb. It'll be a while before you can see again.
Did anyone else notice that the battery was no longer discharging when the amps went low enough for the light to go out? As soon as the light went out the volts bounced back. Was it still discharging? Does the bulb still consume power even though it is not lit?
Joshua Bardwell Good to know. Thanks. I like this idea. I believe this would put less wear and tear on my charger compared to using the internal discharge feature. When the bulb burns out, replace it. 😀
A 120v 100W bulb has a resistance such that it dissipates 100 watts when 120v is applied to it. If 12v was applied to it, it would dissipate approximate 10 watts (1/10th the voltage, 1/10th the wattage). So it would "work" in that nothing would break, but it wouldn't be very effective as a discharger.
Because the charger discharge function is slow. Typically 1 amp maximum. You can use resistors if you like, but the light bulbs are cheaper. A large power resistor gets expensive.
Great vid. This is the only real way to find the true capacity of a battery. Of course in real life a 30 amp load would better mimic a quad. Q. with that external load, is the charger display still giving you actual amps and mAh used?
+ultimate99tube Yes. The amps and charge readout are still accurate. Current in a series circuit is the same at any point in the circuit. So the charger can measure the current no problem.
+Jon Car Reaktor Quadkore. www.hobbyking.com/hobbyking/store/__82840__Turnigy_Reaktor_QuadKore_1200W_80A_4_X_300W_20A_DC_Synchronous_Balance_Charger_Discharger.html
You can put two bulbs in series if you want. This will increase resistance but also decrease discharge rate. I'm not sure why yours is burning out but mine don't.
Thanks Josh, I’ll try that. I thought maybe I just had a bad bulb at first but I toasted 3 of them in a row. I’ll add a second one in series and see how it goes.
+Joshua Bardwell Hey man, big fan of your channel. Super informative stuff! You said you had a link to the bulb and the bulb connector in the descrip? Not seein it lol. Could you link me please?
+Joshua Bardwell Np, thx. So, how do you feel about this charger? I was gonna get a 406 duo, then i saw this. Me and my friends really respect and trust your opinion. I nvr charge faster than one C. And i dont charge anything bigger than 4c. It seems like units with a power supply required are all around better. But this one is ac/dc right? And can it charge Lihv's?
WhomImIzFPV Not AC/DC. You need an external supply, and you want a 24 volt supply to really make the most of it. And it can't charge LiHV. This unit is pretty expensive compared to some other units on the market, but if you're considering a 406 Duo, it's cheap. I like it just fine. If you want to charge LiHV, consider an Accucel 6 80 watt, or two, or three. For more capacity, consider this one: www.hobbyking.com/hobbyking/store/__81837__TURNIGY_MEGA_1344W_40A_Balance_Charger_Discharger.html When considering the Quattro, you have to ask yourself whether you really want 4x 300W charger, or whether a single, larger charger would do the job for you. You can get the same wattage in that Mega charger, for $100 less, if you are willing to settle for a single channel vs. four separate channels.
