How To Parallel Charge LiPo Batteries Without Burning Down Your House 

4 years later, it still really helpful. Thank you!

Good video man. Best line: "Don't do anything dumb, and you'll be OK" - Joshua Bardwell.

At 3:00, are you sure you just want to “walk away” for an hour or two while they charge!? I like to always be in the vicinity. You never know! You are awesome, JB. Seriously my most trusted go-to guy whenever I have an issue. Thanks so much.

man, you are killing it on the instructional videos. i was just thinking about this yesterday... now you laid it out in detail for me and answered all my questions. thumbs up!

"Parallel charging is somewhat of a controversial topic..." FOFL! That there is the understatement of the day... "Don't do anything dumb, and you'll be OK..." is just golden. I couldn't have said it any better myself. :D I'm of the "Parallel charging is just Taunting Murphy" camp. I see it as trading essential safety for the money saved not buying the stack of multiport chargers you SHOULD buy to charge all the batteries you WANT to charge at once. That said... it IS possible to parallel charge safely... as long as you treat your entire charging array as if you ASSUME you'll have a fire one day, and set up your charging station so it can HANDLE a 1400° fire. In all honesty, you REALLY should set up this way ANYWAYS, because ANY LiPo can catch fire AT ANY TIME. Your setup is probably one of the few I've seen that DOESN'T fill me with dread; this is because you are doing it the SMART way. Your setup CANNOT possibly apply more than the 2C-5C charge rate that is safe for most LiPos, so even if things went south and all the current got dumped across one pack, you still wouldn't be over-charging. This is not so with some of the bigger setups that some parallel-charging fans use... that push 40A across the array, and if ONE LiPo goes open-circuit, the setup dumps way too much current across the other LiPos in the array. Also, your chargebox is a great idea; if there is a fire, you just close the lid and throw everything out the door onto your driveway. I use a similar setup on top of 12" ceramic tiles deliberately arranged to be easy to grab & toss. Like anything involving electricity, messing around with it when you don't know what you're doing IS just dumb. So if y'all don't understand the reasons Joshua is advising you to do things the way he is, don't do it! Electrons may be tiny, but when they gang up on you, they ALWAYS WIN. :D

FYI, someone from the Flite Test Fan facebook page pointed me your direction and I am VERY thankful... for them... and you! Thanks for all this help!

I absolutely love the idea of using an ammo box for charging. I might have to steal that.

You were built for this Josh, thanks for taking the time to teach all of us

Great video! I find your channel more detailed in information and more giving than that farting around rotor riot channel. You got tons of info ranging all angles around multi rotor. I'm amazed how much videos you put out.. You have helped me tons. Keep up that great work.

I learned through experimentation that 2C is the sweet spot for almost all of my lipos. I will recondition them in the off season (now) every year by balance charging them at 1C, discharging them down to 3.2 volts per cell, and then balance charge them to 3.7 for storage. I am still running bats I bought over 3 years ago. I have never had one puff from charging (hard flying discharge of course) I have only had a few nanotechs loose a cell balance, and other than torn balance plugs my lipos have served me, and continue to serve me well. What I don't have are any of those smexy ammo cases for stowing my lipos ;)

"come back in an hour or so... and uh.. admire the ashes" lmao, naw this is cool I actually just bought that same style balance board and am using it to charge now, cool to see an example and an explanation from someone who has tested its limits!

lol didn't catch it the first time.. the change in his tone of voice.. 'the 3s is gonna light on fire.. probably..' hahaha

Great video. I have been parallel charging lipos for many years and have not had any sort of "incident". Just use common sense and care and you will be fine. I use parallel charging boards coupled with a series of smart chargers able to charge up to 12 batteries at a time. I, of course, never leave the room when they are charging and have a fire extinguisher at the ready.

I think you forgot a very important point that I'm dealing with at the time. I over discharged some of my batteries and damaged them so hard, that some cells are not able to charge up to 4.2V anymore. The voltage limit of some cells seems to be droped down to 4V. If I charged them parallaly with a healthy batterie the damaged one would very likely take fire for obvious reasons. So a very important point is also to check if the maximum cell voltage of the parallel charging cells are still the same. I would like to hear your oppinion to that. Greetings from Germany

Hey Bardwell, so if I charged all my packs and couldn’t fly them by the 2nd day, is it safe to parallel discharge at like 2C for lipos as well? I’m wondering as I now have to discharge some batteries as I won’t be using the until Saturday lol

Question... Could I connect 2 parallel charging boards together and charge more batteries together?

If you have 1S, 2S or 3S batteries you charge them in series (also the balance plug). That's the proper way without hazard. You can't do it with 4S as the chargers typically only do 6s max. Putting them in parallel ruins the LIPOs if any of those parallel cells have a significant voltage difference, never do that. But you are right: If you check them all, verify all cells are within a very close voltage span you can parallel charge them.

A Hitec 4X is an awesome charger with built in AC 200 watts under $200. Avoid all the complex voltage matching for parallel charging packs in series, and get a couple high quality computer controlled multi-chargers and you can balance charge multiple packs at the same time. Two $200 4X chargers are more logical and safer than one charger trying to parallel charge cells built in series. Li-pol cell internal resistance variances are far too risky when parallel charging cell packs in series.

7 years later, building my first quad(first rc build in general, only experience with like nitro rtr Associated and Traxxas trucks 15 years ago). Bought D6 Pro that hopefully I'll be able to learn parallel charging with

clear instructions thanks! This was old and now we have that JB charger with the fuses you mentioned.

Hi. The stuff you say in this video kind of makes sense but as I'm still new to all this i also have a voice in my head saying "man, he may as well be talking in Egyptian" lol 😂

Great video, I was mainly curious on Why you couldn't put two batteries with different voltage next to each other. I was like " don't they just balance with each other"? Thank you for going into detail about that. It makes sense now in my head so I won't forget lol. I am more likely to remember something if I remember the WHY instead of the WHAT.

Looks like I need a parallel charging board! Thanks.

Thanks! You just answered my previous question I jest left on one of your other videos about discharge levels between batteries when charging.

Hi Joshua I couldn’t think of another way of contacting you, my friend and I have been watching a lot of your videos, while we aren’t flying quads, we have found them to be informative in many ways, we have been using quad motors on fixed wing los and we wondering if you do a video about this facet of the hobby.

So it was early morning I was plugging in my 2s infinity 550s to the board. when plugging in the 3rd battery I accidentally plugged the balance lead into the 3s slot it started at the board like a fuse burning up to dynamite with a small flame following crackling and smouldering. lucky for me I was right there and pulled the battery out ripping the pins out with it. one dumb mistake could have burned my house down all because I was still half asleep and didn't have good lighting to see.

Thanks for this video, i just got a hobbyking para board for my 3s 850mah batteries and using an imax b6 charger. Really clears all questions up. a few people complained that the traces burnt on the board or the balance leads got damaged, i guess because of connecting batteries to far out of charge from each other.

Hi sir JB good day to you.i just wondering why did you charge your battery in 6mah? instead of 4mah.. please correct me if I'm wrong.

Hey sir.. so I watch plenty of your vids over and over again most times..i have a question on this one. Ok. So you explained everything great BUT when you plugged in the batteries, it looked like you just picked which ever port to balance. So I guess it doesn't matter which you use as long as they are all 4s. And can I plug in all my batteries at once

i think you left one tip: CONNECT THE PARALLEL CHARGING BOARD TO THE CHARGER BEFORE PLUGGING YOUR BATTERIES ON THE BOARD! it happened to me that while i was plugging the batteries on the board the two positive and negative banana plugs of the board touched, fortunately the only thing broken was the fuse on the board but it could have been worse.

Very detailed video with instructions. Thanks for sharing your knowledge.

Definitely going to get that chopstick with that specs

JB! Awesome video! I originally found your lipo charger and parallel charging videos as I am getting back into the RC hobby (off-road dirt). Now, after watching your videos, I am considering getting into Drone FPV flying, just for fun (no racing). One question I have that hopefully you can help is this. All the lip parallel charging videos are geared toward smaller mAh batteries (drones) but what about people like me who use larger mAh batters (5200+ mAh) batteries. It does it make sense to go the parallel route with larger packs (due to the high A charge rate to get 1C) or just get a nice dual port charger and charge 2 batteries at the same time. Thoughts?

Great video, thank you! Just one thing, I recently started doing this and I heard from a guy at my local hobby store who recommended not charging batteries that have any individual cells that are out by more than .05v! I was doing this for a while but it was really difficult to achieve and seemed a little excessively cautious. Your way at (.4v or .3v etc...) seems a lot more reasonable as well as attainable. What do you think?

nice video, does it matter which balance ports you plg the battery's into on the board?

Nice video! But i have a question. If Im charging 3x 3s 1000 mah on a parallel what would be my A in charger. Is A means amperage? Sorry for noob question

If a person has an ISDT Q6 charger, and an ISDT Safe Parallel Charging board, how does one send the output from the ISDT Q6 charger output (MALE XT60), into the INPUT of the ISDT Safe Parallel Charging board 'input' (MALE XT60) ? Neither the ISDT Q6, or the ISDT Safe Parallel Charging devices seem to come with cables to bridge between them, and on the sites i've looked at, nobody seems to sell a FEMALE to FEMALE XT60 charging 'bridge cable' set to go between the Q6 outputs and the Safe Parallel Charging device... what am i not understanding?? P.S. i am going to order a metal ammo can for this too.

I would love to know the name or get a link for the board you used in this vid

My 6S CNHL batteries say they can be charged at 5C. They do not compare the # of charges the battery will last at this rate versus 4, 3, 2, or 1C. I charge at 1C to be safe and I know some guys who charge batteries for flashlights who are not willing to charge more than 0.2C! So ... what rate do you charge at? BTW, I accidentally connected my 4S to the parallel board which already had several discharged 6S connected and in just 15s or less the 4S got warm and charged to 4.3V per cell ... definitely something I have to keep an eye on as I wasn't even thinking how these back-feed without the charger going!! Thanks for sharing this video Joshua!

i took my ammo box and coated with sprayin liner lol since i do sprayin bedcoating for living

I would recommend using a bat-safe box instead of the ammo box :)

This question haunts me in my dreams: when you connect lipos with different cell voltage to a parallel board, the cell voltage balance out anyways after some time? Is there a maximum on discrepancy between the voltage of each cell for parallel charging? What if I keep them connected some time until they all have the same voltage - is it save?

Joshua Bardwell Hiya josh what's the best way to recover a low cell on a battery pack iv not been able to get out flying for a while and I was checking my pack's and I'm getting a very low alarm on one of the cell and not letting me change it I had this before but I can't remember how I recovered it the last time lol I think I put it on a low ni-mh or ni-cd for 5-10 mins to get the low cell backup to a stable enough for a slow lipo change this only happens to my battery on base station and goggles and I got a small battery &cell checker to add on mt fpv setup but I need to find the best way to recover a low cell on a battery pack safely josh what's your advice on this

Thank You for yet another very informative vid ,i'm just starting up in FPV (waiting for my very 1st quad/drone/ meh the fun toy with spinning thingy's =D ) and a small one to fly inside & learn . for safety charging I have an old steel tool box that should be good enough it close up pretty tight but not 100% so if some thing happens it wont turn into a bomb .You mentioned something about electrical tape This ->www.permatex.com/products/adhesives-sealants/specialty-adhesives/permatex-liquid-electrical-tape/ is what I have been using for years ,it great specially if you can dip the part in it let partially dry 30ish min and do two coats .I sealed many accessories on my e-bike with it never had problems with water on them . Congratulation Josh on going all out with your FPV Passion ,full time youtuber I mean ;-) I usually end my comments with ride safe in this case I have to say " Ride & Fly Safe " 1 last thingy ,if you ride a bicycle don't stay in a car/truck blind spot ,sadly again this season cyclist where badly injured for having stayed in that zone ,some dead …. Fly& Ride Safe ;-)

Hi Joshua. With these parallel charging boards, is there a specific order for the balance ports in relation to their XT60 ports? E.g. First XT60 port uses the top left bunch of balance ports, so on and so forth, or are they all the same and I can simply plug my battery balance leads into any convenient port? Thanks.

Does it make sense to keep a check on the temperature of the batteries because usually they heat up before they catch fire, right? So if you touch them and they're extremely hot that would be a sign that you're charging with too high of a amperage or that something is wrong. I sometimes charge 3 850mah batteries at 3A. Should it be lower?

You mention sparking ... when I connect the battery to my quad, I can hear it snap/pop/spark ... is that to be expected?

I'm thinking if i should buy an Ammo Crate and a bag of sand to put on top of it. In case there's a fire, the bag of sand will break and drop all the sand ontop of the cells.

Rotor Rio guys say try to keep lipos below 1V difference is it still safe or it must be 0.4V for 4s or 0.3V for 3s ?

You're plugging your balance lead in the 6S port of the charger while you're charging 4S. Is the charger knows automatically that it needs to balance charge with the 6S port while charging at 14.8 V ? I ordered your V1 parallel charging board, can't wait to try it !!

Why did you only charge four when you have six slots? Can you do six at a time and does it matter what side the balance lead is at?

My power supply is rated at 1500w 24v 62a and my charger is the ISDT T8. I am using the JB fused parallel charging board and am charging 4s batteries. Assuming all are within .4 of eachother and all are the same make and brand, is it OK to charge 1500's and 1800's together?

does it matter which set of balance connectors on that parrallel board you plug into? for example if I'm charging 4 4s batteries, can I just choose 4 random 4s balance connectors to plug into?

So just to clarify this - I have an Accucell-6 like yours, and I just got a parallel board. I plan to charge x4 4s 1300 mah batteries with it. I did the math and I believe if I tried to charge them at a charge rate of 5.2 amps, I would end up pushing potentially 87.36 watts, which is more than the Accucell can do. I read from Oscar Liang that the Accucell will auto-detect that I'm trying to overdo the power, and will automatically adjust the charge rate to safely charge. - Edit - I assume this is why you max your charger out @ 6 amps knowing that it won't push that much amperage. For now I just plan to charge 2 of them at a time at a 2.6 amp charge rate, which seems safer for my charger. What do you think? Should I just go ahead and carefully try charging all 4? Sorry for the wall of text

Do cell resistance differences matter ?

Extremely informative. Thank you!

I feel like it could be easily avoided just by buying something like SkyRC Q200 4-challel charger.

Well.. the charger I have is a 3s-4s only.. parallel charging board is a up to 6s one. So the connectors don't fit on my charger.. what I did was get one battery and plug it's battery checking cable to the charger .. and the power cable is going to the actually parallel board instead of the charger. I then place the other batteries with both cables on the parallel board.. right now they are charging fine however they are charging rather slow. But Im seating next to it. Already checked them 3 times and they are all charging even.. if all checks out, should I keep doing this? I don't wanna buy another charger ..

Bardwell...Good vid but maybe time for an updated vid?... addressing different MAH / new high C ratings/ voltage differences / new 6S trend / board daisy chaining misconceptions. The old rule of thumb of 0.1v per cell difference is often mistaken for the total 4S lipo (0.4) voltage. Theoretical question: If my lipo says it can be charged at 5C then why is it a fire risk to plug in six 4S 1300 100C lipos at say 14.4, 15, 15, 15, 15, 15...? Won't the weakest lipo just be equalized at a 5C charge current? Thank you.

I noticed that you used the balance charging function when charging in parallel charging. Are you still able to parallel charge safely using the normal charging function?

Hello Joshua, I'm new to the hobby and I'm starting to charge my batteries in paraller. Currently I have 5 3s batteries - 3pcs GNB 550mah and 2pcs of Tattu 650mah, my question is can I charge them in paraller all together at once?

Parallel charging 4-4s 1300mah batteries on that charger is kinda pushing it as far as the wattage is concerned. I have the Turnigy Accucell 6 10A version and it gets pretty warm parallel charging in that configuration. I never really understood why they designed those chargers with such a low wattage spec. They are really nice chargers for the money. Parallel charging 4-4s batteries is actually 87.36 watts which comes in a little over the 80W limit for these chargers but hey who cares right? If it blows we can just pick up a new one for how cheap they are. I've been looking at picking up the Hyperion Eos 730i NET 3 charger so I can do 8 4s batteries at one time? Heard anything bad about the Hyperion line? Keep up the good videos, I really enjoy your channel and your informative ones are easy to understand and highly useful. Thanks again, happy flying....

Joshua Bardwell Hiya josh iv always charged my 4> 4s lipo.s at 2A is that good for them just when you said a slow charge is better and will this give a longer lifespan bye any chance

How fast parallel connected batteries equalize each other, when you first connect them on board? Maybe one battery charges above its max. C rating? I couldn't find an answer on web.

Any limitation on the charge method with parallel charging? Or can I use balance charging with multiple batteries plugged in?

Joshua would it affect anything if I created extensions for each battery so that they aren't all piled up so close on each other? I wonder if there's a way to do that with the balance leads too? Just a thought. I would buy a set of these if someone sold them. Maybe they do.

Hi Joshua. Just started flying again. Question about my 4s lipos. The 4th cell and sometimes 2 cell are out by alot Even after a single balance charge them. After flying 14.8 3.77, 3.72, 3.72, 3.66 Once balanced Its 16.8 or 16.7 But 4.2 or 4.19 on 3 but the forth is 4.14 or even 4.08. Is my charge out of wack or are my lipos toast? Most of the time the charger says 16.8v and 4.2 per cell when charged however I check them with my meter and they read as above. Is my lipos toast or is the charger wonky. I use a venom pro duo Thanks for the help

I have you parallel charge boards in 4s and 6s. My 6s board only shows 5 batteries in the green voltage display at the top of the board. All fuses look to be intact, so only charge 5 at a time is 10 that the board allows. Any clues as to what might be happening?

My instructions said to plug the balance plugs in first, and then the power plugs.

Always keep a class D fire extinguisher nearby! I even mounted one on my truck just to have nearby when I'm flying, just b/c ya never know! Lol can get a small marine grade one at Walmart for $25, small but enough to put out a LiPo fire 👍

Thanks for talking me through my first parallel charging of 3s I notice that my JB charge board looks different than my bang good board. Is there a how to for the jb board, or is it exactly the same, just with nicer components?

Question on the amp setting in the battery. Why did you set the charger to 6A? you have 4 1300mah lipos so thatd mean 4x1.3=5.2A so youre overcharging at 6A no? EDIT: Ok so i think I got it. Youre using the 1C charge rule right? Basically at a 6A charge rate (6/4=1.5A) youre charging each battery at 1.5C? So if you had 4 4s 1300mah lipos with a max 5c charge rate and a capable charger you could theoratically max charge at 26A right? (1.3A x 5c= 6.5A, 6.5A x 4 lipos= 26A charge rate?)

Is it Importamt to Plug the balancer cable into a certain Port or is that randomly?

why the velcro on the packs? just curious. I will be applying some to my Apex for batts, but wondering if that's the reason yours are velcro'd

@Joshua Bardwell a question , you said that the battery needs to be at the same voltage or very similar to each other to prevent high current flows ok? But if we connect a resistor lest say 50 ohm to the xt60 port and to the balancing port , this will reduce the current flow and let us plug in Lipo with different voltage , more than 0.4 (same cells ) am i right?

What are the red/blue packs in the ammo box?

I use different strategy to charge my battery park. When i'm going out for a flight day to the nearest field i take only about 4 4s 1500mah flight batteries and couple of old 6S 10000mah batteries coupled with ISDT pocket chargers. All my flight batteries are graphenes lipos, means i can charge them at up to 15C rate. 15C is too much, but at 6C it takes about 10 min to re-charge the battery. So my rotation is following: 1 flying, 1 cooling down after flight, 2 charging. Given the flight cycle duration of about 6 min(3-4min to fly, 2-3min to swap batteries, do some tuning, take rest for the eyes) i get new battery by the end of every cycle ready to be installed on quad. This way you can get about 20-22 flight non-stop per flight day. With parallel charging you will have to take 1 big brake to charge them all. Yes, i know that charging at 5-6C is not good for battery cells, but so far i don't see much degradation in battery life and performance. Statistically, my batteries life is about 30-50 cycles, before it get's smashed into the ground as a result of the crash.

Hi! Nice video! I've two big 5200mah 3S battery that I use for my multicopter. Does it mind if sometimes I connect them in parallel (following your voltage rule) using only the main discarge lead (using a Y style cable) an charging them together without using balance plugs? I'll balance them every other charge for example :) edit. I just remembered that one of the battery has a 4S balance plug but with only 3 cells connected (cause I've broken the 3S balance lead in crash). I think In this case I'm good to go. Just use the Y cable and connect both the balance to 3S and 4S plug on the charger :). I have your model and the balance connectors should be all in parallel.

2 questions, can you Parallel LiFe's ? and when charging LiPos like this will they balance ?

Hi Josh, an FPV guy told me I could equalize multiple batteries (sane Ss and mAhs) by plugging them into a parallel board for 15min (without charging). Is this true? Thanks

Just recently came back to this video. You show plugging the XT60 in before the balance lead. Others say its the opposite, Im so confused.

VERY good and easy to understand video! Great job

I've heard of the dead kitten issue...that's definitely a problem...for some...Personally I hate cats but not enough to burn my house down to get rid of the litter box HAHA

Can you please tell us where/how you are mounting the temp sensor?

I don't think you covered this in video, but could you do storage discharge in parallel?

Somewhat doubtful how to handle the rule where all cells must be within .1 volts, before para charging. See, I have the same charger, Turnigy accucell 6... After a session of running a few batteries dry, I must get them all within .1, right? So I must hook them all up individually and It would make sense to balance them all to their collective average volt... But the Accucell 6 doesn't let me chose an end voltage, only different settings such as storage (14.2) or balance (16.8)... So my current strategy is getting all my 4S's too storage (14.2) and then para them together to 16.8. Is that the best I can do with this charger? Is there really no way to chose my own custom end-voltage, either total or per cell? It just seems like a waste of time getting them all to 14.2, theyre all around 13.3V +/- .3V

within 0.4 of the full pack voltage? I am new to this so just making sure, I if I have 2 packs, one at 15.33 and one at 15.43 then they are fine? And what DO you do when they are more than .4? Do you just toss them in the drone and hit them a bit? Do you plug them into an led board? Any suggestions to discharge one down without turning on your charger?

Always helpful!👌👌🥇🏆🍾

DONT WALK AWAY lmfaoo

No issues with the accucel 6? How many batteries do you think you can get going off a single charger? I only fly about half as much as I could since I have to spend the whole day before swapping packs on and off the charger.

Can I have 3 batteries on charge in parallel? Or does it have to be even numbers?

In this balance board , is it important wich balance port you use ? Is each xt60 port related to 1 specific balance port ?

Do you have a video showing the installation of the charger in the ammo box?

1300mAh x 4 is 5200mA. 50W or 6A is the highest current your Turnigy Accucell 6 will output to the 4s (3.7v x 4 =) 14.8v (or is it 16.8v) 50w/14.8v = 3.38A to the 5200mA 4p4s target. could one use a power supply which outputs 18v 6A ? if you wanted to charge 8 1p4s batteries simultaneously could one use an 18v 12A power supply? I missed the reason to use a balance board with the balance leads in this collection of 4s batteries in parallel.

My smart charger doesn't do LiHV .. stopped on brand new 3S 300mah at 12.05V .. balance charge 0.1A

Hy Joshua, I was wandering instead of buying a normal charger that charges 6 batteries at the same time and a parallel board, to buy 6 of this: Hobbyking® DC-4S Balance Charger & Cell Checker 30w 2s~4s, do you know if it's a good idea? thanks

I have a 4s balance charger. Will a 6s parallell board work with a 4s balance lead extension, or do I need to rearrange the wires to make it work? I noticed this one has a black and red wire at each end suggesting Supply and GND. I'm guessing I'll need to make sure the 4s balance lead's black and red wires correspond to the boards black and red wire locations, no?

Is there no smart parallel charge board, that will run all the checks automaticaly before unlocking the connections between batteries and stuff?

„And its done. Boom.”😅

Thank you, this is just what i wanted. Great video :)