tag:blogger.com,1999:blog-5854741938955568545.post7259305167942143941..comments2024-03-26T01:53:19.600-07:00Comments on ElectricRCAircraftGuy.com--RC, Arduino, Programming, & Electronics: Parallel Charging Your LiPo BatteriesGabriel Stapleshttp://www.blogger.com/profile/10071071884455787806noreply@blogger.comBlogger26125tag:blogger.com,1999:blog-5854741938955568545.post-83777731844918320562021-09-03T10:58:33.526-07:002021-09-03T10:58:33.526-07:00Hi, Maybe I am missing it (not smart enough?), but...Hi, Maybe I am missing it (not smart enough?), but how would you wire a balance plug to a 2S battery wired in parallel to provide 3.7V? Or is not important?<br /><br />Thanks,<br />AndyAnonymoushttps://www.blogger.com/profile/14746901940419295664noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-85331487293548760672021-04-15T22:26:02.816-07:002021-04-15T22:26:02.816-07:00Excellent info and good explanation of everything ...Excellent info and good explanation of everything important, well done !!!<br />Thank you for taking the time to help us beginners !Quetianohttps://www.blogger.com/profile/03779664909043899944noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-73108428632632791322020-06-08T01:28:49.052-07:002020-06-08T01:28:49.052-07:00"Reply" button to reply to comments is n..."Reply" button to reply to comments is now fixed! I had a bug in my website template.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-74009179993971584042020-06-01T10:04:41.015-07:002020-06-01T10:04:41.015-07:00testtestGabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-90542098024686509622018-11-18T14:56:33.375-08:002018-11-18T14:56:33.375-08:00Rule of thumb: choose your power supply to be able...Rule of thumb: choose your power supply to be able to provide at least 30% (the more the better) more power than the power rating of the charger. It's that simple. If your charger is limited to 500W, for instance, choose a power supply that is 500x1.3 = 650W. This will keep your power supply from overheating even while your charger is pulling everything it's got (500W in this case), and a smart charger will automatically limit itself via its built-in micro-processor and C code-based firmware to keep itself from pulling more than 500W while charging, regardless of what the batteries want. Make sense?<br /><br />A <a href="https://www.google.com/search?q=ISDT+T8&rlz=1C1CHFX_enUS602US602&oq=ISDT+T8&aqs=chrome..69i57.420j0j4&sourceid=chrome&ie=UTF-8" rel="nofollow">quick google search</a> of your charger seems to indicate it is a 1000W charger, so I'd recommend 1300W or more. Now, of course there are some caveats. As always, knowledge is power. If you know what you are doing, you can run your charger on a 500W power supply, or even a 100W or 50W power supply. How? Answer: have the *knowledge* to never set your charger to use more than ~70% or so of the power supply's max power. Remember that Power = Voltage x Current, or in units: Watts = Volts x Amps. So if you are charging a 3S LiPo and have a 100W charger, then I'd recommend pulling 70W or less. A 3S LiPo is full at 12.6V, so what's the max current setting we should use? Answer: 70W / 12.6V = 5.6A. Stay below that and you're fine for this setup. Make sense? Use your equipment within its limits and you'll be ok. The basic equations you need are Ohm's Law and the power equation. V = I x R. P = I x V = I^2 x R = V^2 / R. Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-58020592001927000092018-11-18T14:33:44.490-08:002018-11-18T14:33:44.490-08:00I read your article about parallel charging and ha...I read your article about parallel charging and have a question? I am ordered an ISDT T8 charger and parallel board. I mostly use 3S2200 mAh packs. My problem is how do I determine my powersupply? <br />I was looking at 500watt but not sure if it will be sufficient. Thank you<br />JohanFromSAhttps://www.blogger.com/profile/18019945914866634357noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-1669926452873154732017-05-18T15:49:18.124-07:002017-05-18T15:49:18.124-07:00I made a video. Not exactly the most exciting but ...I made a video. Not exactly the most exciting but it will do: <a href="https://www.youtube.com/watch?v=v9DQnJ0H3_g" rel="nofollow">How to Use a Power Meter to Safety put 10 x 3S LiPo Batteries in Parallel for Charging</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-43754632974554590372014-05-27T18:48:45.832-07:002014-05-27T18:48:45.832-07:00Sorry, I don't have a tutorial on this yet. I...Sorry, I don't have a tutorial on this yet. I should post a video sometime, as it could be very useful to show what I personally do. One simple technique is to get alligator clip probes for your multimeter (voltmeter). Then, measure and write down the resting voltages for two batteries, then hook your probes up to your balance board main leads, being careful not to let them touch together. Plug in your two main leads for your LiPos, into the parallel board, and watch what happens to the voltage on the voltmeter. It should show roughly the average of the two batteries's voltages, assuming they are equal capacities. <br /><br />Here are some examples of a power meter/watt meter:<br />1) Watt's Up Power meter - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLMV0<br />2) Electrifly Power meter - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBHDT&P=ML<br />3) Hobbyking - many assorted varieties - http://www.hobbyking.com/hobbyking/store/__471__157__Tools-Watt_Meter.html<br /><br />-If using a multi-meter, keep in mind it is rated to 10A max usually. The nice thing about the watt/power meters above, is that many of them can go up to 100A. If using a multi-meter, move your probes to the proper holes: black to COM and red to A (Amps). Then, hook the multimeter in *series* with *one* of your LiPo's leads, to be in parallel with another lipo. Plug the second LiPo lead straight into the other lipo. Now, the multi-meter is in series with a single lead which connects two LiPos, while the two Lipos themselves are in parallel with each other. By "in line" I simply meant "in series."<br /><br />Also, the 15 min rule is a rough estimate, as there are *many* factors involved, but is at least a ball-park rule-of-thumb. Remember not to let your battery States of Charge (% full values) be more than ~25% apart, or else you risk damaging the lower-charged battery. <br /><br />As for your procedures, those are correct. Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-59134491762146602472014-05-26T21:41:18.906-07:002014-05-26T21:41:18.906-07:00Is there a tutorial on this? Sounds like something...Is there a tutorial on this? Sounds like something you do before connecting to charger or balance board? Not familiar with "Power Meter". If using a multi-meter, what do you set it to and what is "in-line"? I'm familiar with parallel or series connections.<br /><br />Thanks for the explanation of voltage averaging. As your chart above shows, it takes under 15 minutes. So, you connect to Parallel-Board in this order:<br />- To Charger Main red/black leads<br />- To Charger Balance<br />- Battery's main leads to Parallel-Board<br />- Battery's balance lead to Parallel-Board<br />And then wait up to 15 minutes before starting charge.<br />Sound about right to follow all safety warnings and passive balance suggestions?Tesla1856https://www.blogger.com/profile/12858038899970631074noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-4158035843118702932014-05-26T20:14:20.937-07:002014-05-26T20:14:20.937-07:00Also, grab a voltmeter and manually measure the so...Also, grab a voltmeter and manually measure the some batteries alone, and immediately after you plug them in parallel, and it will give you a lot of insight as to what the voltmeter sees. Rig/solder up some special harnesses if necessary, and compare resting cell voltages to combined cell voltages too, immediately after plugging some cells in parallel. Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-17915221795868533802014-05-26T19:51:10.524-07:002014-05-26T19:51:10.524-07:00"However, I guess we just have to assume it&#..."However, I guess we just have to assume it's happening, because there is no way to verify or control it."<br /><br />I don't like to assume, so nearly every time I parallel charge, I verify it's happening. I do this by putting a power meter in line between the two packs, so that it will measure the current from the high pack to the low pack. When the current is zero, the packs are equalized. When the current is high, I won't even start the charger. I monitor this to make sure the current is not high enough to damage the lower-charged pack.<br /><br />If Battery 1-cell 1 is 3.0V and batter2-cell 1 is 3.7V, the second you plug them in together, a volt-meter (or charger) will read their average, or 3.35V. Voltage is the electrical equivalent to "pressure." If pressure is escaping from a high-pressure tank (3.7V cell) to a lower pressure tank (3.0V cell), and you try to measure the pressure back from the two of them combined, you'll basically read the average of the two, even if they haven't equalized yet. Plus, the bulk of the equalization happens pretty quickly. <br /><br />Grab a power meter and try it.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-23966669059734259112014-05-26T19:40:58.818-07:002014-05-26T19:40:58.818-07:00Yes, this is what I was missing ... cells in paral...Yes, this is what I was missing ... cells in parallel do *not* need active balancing by a smart charger. Rather, they naturally, by the laws of physics, will perform passive balancing. Cells in parallel automatically, passively, due to voltage gradients (differences), self-balance until they are equal.<br /><br />However, I guess we just have to assume it's happening, because there is no way to verify or control it.<br /><br />Also, wouldn't it be possible for Battery1-Cell1 to be 3.0v and Battery2-Cell1 to be 3.7v and the charger not even know it? It would read as 3.7v (? I think) and not charge (or not charge much) ... all the while Battery1-Cell2 is correctly charged to 3.7v and the pack is out-of-balance.Tesla1856https://www.blogger.com/profile/12858038899970631074noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-68924570470411100092014-05-26T19:05:19.585-07:002014-05-26T19:05:19.585-07:00Vince, it sounds like you're on the right trac...Vince, it sounds like you're on the right track, but still missing a little bit in regards to what is going on in parallel charging, so I would say that yes you explained things correctly, except for the one thing I will address momentarily, and no, in regards to individual-cell balancing, your concerns are not justified. <br /><br />Here's the scoop:<br />With cells in series, and no balance lead, your charger has no idea how much voltage is in an individual cell; it only knows the total voltage. If it reads 7.4V, that might be cell 1 with 4.2V and cell 2 with 3.2V, or it might be cell 1 with 3.7V and cell 2 with 3.7V, or it might be something else. Unless the charger connects to the balance lead, it just doesn't know. So, let's imagine it's the first case. You start charging, with cell 1 at 4.2V and cell 2 at 3.2V, and the charger says, "ok, I need to see 8.4V before I stop, so I've got a long ways to go," when in actuality it is going to overcharge cell 1 and possibly blow it up or catch it on fire, and definitely it is going to ruin or at least damage cell 1 at a bare minimum. That's where active balancing comes in. Cells in series must be *actively* balance by a smart charger, to get them to be equal.<br /><br />However, here's what you're missing still: cells in parallel do *not* need active balancing by a smart charger. Rather, they naturally, by the laws of physics, will perform passive balancing. Cells in parallel automatically, passively, due to voltage gradients (differences), self-balance until they are equal. If you take 2 individual LiPo cells, and place them in parallel, and wait long enough, no matter what voltages they *were*, they will equalize, automatically, to become *equal* voltages over time. One will discharge into the other, until they are equal. <br /><br />So, in your case of 2 7.4V LiPos, when you place the whole packs in parallel, and the balance leads in parallel too, cell 1 of pack 1 is placed in parallel with cell 1 of pack 2, so both cell 1's will automatically, by the laws of physics, passively balance until they are equal. Both cell 2's will also passively balance until they are equal, since cell 2 of pack 1 is also in parallel with cell 2 of pack 2. However, both cell 1s (as if a large single cell) are still in series with both cell 2s (as if a large single cell), so *active* balancing is still required here, to get the cells in *series* actively balanced, and that's where the smart charger does its job.<br /><br />Therefore, when charging in parallel, you are still getting all 4 cells to be balanced, just as if you were not charging in parallel. <br /><br />Remember to be careful about large voltage gradients (differences), however, as the passive balancing can be quite fierce (and potentially damaging or even dangerous), if cell voltage differences are too great before being placed in parallel--refer back to my article for warnings & recommendations on this.<br /><br />I hope this all makes sense, please do respond to let me know.<br /><br />Thanks!<br />~GabrielGabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-62200065073918402182014-05-26T17:51:39.188-07:002014-05-26T17:51:39.188-07:00Excellent article, thanks. I’m an RC old-timer (or...Excellent article, thanks. I’m an RC old-timer (original Triton owner with NiCD and NiMh batteries) but getting into and learning LiPos now. Helping my brother with Traxxas EZ-Peak Plus 6amp LiPo Charger. Charger works great for charging single LiPo and balances each cell on the preferred Balance Charge. So then, he purchased a CommonSenseRC Paraboard PRBRD-TRX (looks similar to yours pictured above). When charging 2, we leave the Balanced Charge Program the same as charging a single 7.4v 2C 5800mah except we change it to 11,600mah. Again, it seems to work fine … but obviously, takes twice as long. Life is good, but here is my question. I understand how parallel boards are wired and why it works. The battery charger really just sees one large 7.4v 2C 11,600mah LiPo battery. But again, it only sees 2 cells and there are really 4-CELLS. Doesn’t that kind of defeat the whole purpose of a precise individual-cell Balanced Charge? I can see why it’s slightly better with 2cell batteries (and might be more of a benefit 3 or more cell LiPos) but even then, it’s treating two LiPos cells as one (that are just in different battery sets). Is my understanding of parallel charging correct? Are my concerns justified?Tesla1856https://www.blogger.com/profile/12858038899970631074noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-11153744928344053072014-02-17T17:34:29.020-08:002014-02-17T17:34:29.020-08:00Yes, increase the capacity limit to ~1.1 x the tot...Yes, increase the capacity limit to ~1.1 x the total capacity of the parallel pack you are charging. So, for 4 3300mAh LiPos, that's 13200mAh (like you stated) x 1.1 = 14520mAh. If you can, set your charger to 14500mAh or so capacity limit. If it can't go that high (it may be limited by its firmware), just set it to the max setting, and you'll have to restart your charger every time it hits this limit and stops.<br /><br />The purpose of this "capacity limit" setting, by the way, is really just to be an additional safety feature to ensure that the batteries don't keep charging and charging and charging and possibly catch fire....which I suppose could happen in some really bizarre situation where the voltage detection circuit fails.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-72749878411727582552014-02-17T12:47:26.793-08:002014-02-17T12:47:26.793-08:00. I do have one question for you concerning parall.... I do have one question for you concerning parallel charging. I have (4) 3S 3300 mAh batteries. My charger is a Thunder 0620AC (20amps-300watts). I set my charger for Lipo 3s at 13.2amps (4x3.3). After about 40mins, it will quit charging stating Termination due to Capacity cut-off. There is a setting in the charger for Capacity Cut-off which the default is 5000mAh.<br />My question to you is, Since I’m charging (4) 3300mAh batteries in Parallel, the total mAh is 13200. Should I change the default on the charger to a value higher than 5000 when charging batteries in parallel. The charger works fine if I’m just charging (1) battery. I cannot find an online manual for this charger and the manual that comes with it is very vague. <br />Kenhttps://www.blogger.com/profile/06701055016085492517noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-21903731153561964412013-06-25T16:38:47.174-07:002013-06-25T16:38:47.174-07:00FYI: if you are planning on using a cheap 3S LiPo ...FYI: if you are planning on using a cheap 3S LiPo balance charger to charge your tiny 1S Lipos (120mAh, for example), this is a bad idea, as the cheapo 3S charger will charge them at too high a rate, and damage them. If the batteries are ~800mAh or larger, however, they should be ok in such a charger.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-30370404495101559042013-06-25T16:29:41.102-07:002013-06-25T16:29:41.102-07:00The way you described it will NOT work. The cells ...The way you described it will NOT work. The cells do NOT share a common ground on the balance lead. I made that assumption before I understood this stuff as well (prior to spending literally hundreds of hrs. learning about this stuff since I love it so much:) ), and I learned the following: for a 3-cell LiPo there are 4 wires on the balance plug. Lets label them 1 2 3 4 from left to right. Let's assume 1 is the most negative (usu. the black one), 4 is the most positive (usu. the red one). The cell voltages are as follows: The voltage across wires 1 and 2 = Cell 1 (a Lipo ranges from 3.0~4.2V/cell, and is 3.7V nominally]). Across wires 2 and 3 = Cell 2, and across wires 3 and 4 = Cell 3. Across wires 1 and 4 = the voltage of the entire 3S battery pack. See my schematic called "Schematic of 3S LiPo Battery Pack (3 LiPo Cells in Series)" in my large document, currently on pg. 26, here: <br />https://sites.google.com/site/electricrcaircraftguru/.<br /><br />Ok, now, what you want to do is definitely possible. What you are describing is called "Serial charging." Google it. To wire 3 1S Lipos in Serial, wire the - on one LiPo to the + on another, and that + to the - on the next one, and that - to the + on the next one, etc., as my diagram shows. Make sure to use 3 1S batteries of the same capacity (or one of the 1S batteries will fill up way before the others) and similar discharge state (again, for same reason as before). Also, make sure to use a BALANCE Charger and do a BALANCE Charge. For 3 1S Lipos in series, charge them as a 3S LiPo at a rate equal to the Capacity of one of the batteries alone. Ex: Serial charging 3 120 mAh 1S Lipos in series means you should charge them as a 3S (11.1V) 120 mAh pack, or in other words, choose the 3S (11.1V) charge setting at a rate of ~0.1A. If you serial charge a 120mAh pack with a 350mAh pack and a 500mAh pack, all in series (not recommended, but possible on some chargers with sufficient balance node discharge current capability), again, remember to choose the 3S (11.1V) charge setting, but charge at the lower rate of 0.1A (corresponding to the 120mAh LiPo), NOT the higher rate of 0.5A (corresponding to the 500mAh LiPo). <br /><br />Does this all make sense?<br /><br />Quick Summary: <br />------------------------<br />For Parallel Charging, you MUST use same cell-count (Voltage) batteries, but capacity doesn't matter. For charging, add the capacities together and use the cell-count of any one of the batteries (since they are all the same cell-count). <br /><br />For Serial Charging, you REALLY SHOULD use same *capacity* (mAh) batteries, but cell-count (Voltage) doesn't matter. For charging, add the *cell counts* together and use the capacity of the lowest capacity battery (though they should all be the same capacity).Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-11521215235072376172013-06-25T15:54:06.489-07:002013-06-25T15:54:06.489-07:00Let's make that 3 things: one more came to me ...Let's make that 3 things: one more came to me that I had forgotten to mention: 3) Temperature. A warm battery has a lower internal resistance. Ex: flying in the Summer, when my battery starts out fully charged and is 80 deg F, my NutBall (see http://electricrcaircraftguru.blogspot.com/2013/02/this-is-what-my-nutball-can-do.html) pulls about 27A peak, but in the Winter, when the battery starts out at ~30 deg F, the motor might only be able to get ~22A peak or so. As the battery warms up in flight, the current may increase a little as the internal resistance decreases, but it will not deliver as much power as it will in the summer. Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-444161057110542672013-06-24T13:27:08.648-07:002013-06-24T13:27:08.648-07:00Is it possible to charge 3 3.7 1s batteries if you...Is it possible to charge 3 3.7 1s batteries if you wire each JST connector to a different lead on the jst-xh for a 3 cell charger and all the commons together. Does each lead put out 3.7 volt?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-53997381040346812372013-06-23T15:08:06.988-07:002013-06-23T15:08:06.988-07:00One more point of clarity: 2 things actually will ...One more point of clarity: 2 things actually will decrease the internal resistance of a battery: 1) Size (Capacity [mAh]) and 2) C-rating. The higher the capacity (mAh) of a battery, the lower the internal resistance. Also, the higher the C-rating, the lower the internal resistance.<br />And....the lower the internal resistance, the higher the current the battery can deliver.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-23352957785179040172013-06-23T14:55:57.163-07:002013-06-23T14:55:57.163-07:00Short answer: yes, charge them all together. As l...Short answer: yes, charge them all together. As long as they are at similar states of charge/discharge (ie: at similar voltage levels), you should be fine.<br /><br />Longer answer: be a touch more cautious with ensuring they are at similar charge/discharge states before you plug them in parallel together, and make sure to wait plenty of time for them to equalize their voltages before beginning the charge. Something to be aware of is that if the smaller batteries are at a significantly lower voltage than the larger batteries, they could receive a substantial current for a long enough time to possibly damage them. This is because larger batteries will be able to provide a current to smaller batteries for a longer time period than smaller batteries could provide that current. Additionally, larger capacity batteries have a lower internal resistance than smaller capacity batteries, so they can deliver higher currents. This applies to plugging them in parallel. Ex: A 5500mAh 3S Lipo at 3.7V/cell, for example, will push a higher current, for a longer time period, into a 1200mAh 3S Lipo at 3.6V/cell than will a 1200mAh 3S Lipo at 3.7V/cell push into a 1200mAh 3S Lipo at 3.6V/cell. Make sense? <br /><br />Anyway, plug in a power meter between the parallel charge board and the lowest-charged battery to see how current flows into it as you plug in the other batteries to the parallel charge board. This will give you a lot of clarity and insight into what's really going on.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-32301340000633644492013-06-23T10:33:51.942-07:002013-06-23T10:33:51.942-07:00Hey, great guide! I was at one of the sites you pr...Hey, great guide! I was at one of the sites you provide link to and i read this: "There is no need to match the capacity, C-rating, age or brand for parallel charging. For example you can charge a 3s 2200mAh 15C lipo, a 3s 3200mAh 25C lipo and a 3s 850mAh 35C lipo together". So it looks like i can charge different capacities. I have 3x 5500mAh 3S and 4x 1200mAh 3S. Do you think i can charge them together? Anonymoushttps://www.blogger.com/profile/16824967570827256234noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-35710358435781408082013-05-05T10:27:07.943-07:002013-05-05T10:27:07.943-07:00Awesome, what flight school?Awesome, what flight school?Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-60767701814570456002013-05-05T08:38:53.122-07:002013-05-05T08:38:53.122-07:00Very clear and concise info on Charging batteries ...Very clear and concise info on Charging batteries especially LiPos<br />Thanks for all the great info, I will be using this info shortly to start parallel charging batteries for my new flight school.Anonymousnoreply@blogger.com