#Need advice on parallel chargers and more

162 messages · Page 1 of 1 (latest)

ashen mantle
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hello guys, i have five 4s batteries and they take a while to charge so i looked at the JB parallel charger but idk if my charger has enough output to charge the batteries all at once and the parallel charger comes at a cost is their a cheaper alternative - thank you -

sullen shadow
sonic sparrow
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I DIYed my own Parallel Charging Boards (properly named PCBs). Much cheaper. I think a 8x 6S one with Polyfuses and all was like 9€ incl. shipping and tax for the LCSC parts
But you have to order from 3 places (AliExpress for XT60s, LCSC for polyfuses, fuses, as well as plugs, and JLCPCB for the printed circuit boards (the actual PCBs))

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I can give you the gerber files for JLCPCB but you have to do ordering and all yourself. And it's very polarizing. I like the fact I have no wires in between chargers and any of the PCBs, and I like the cable-less daisy-chaining, but not everyone does. And it's perfectly designed for my charger, but subpar for other chargers, and you have to get 5 of those to get to that price 😅

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my answer is for the second part (the cost)

ashen mantle
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charger is toolkit rc m7

sullen shadow
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@ashen mantle and what PSU?

ashen mantle
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what is psu

sullen shadow
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power supply

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power brick

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or do you have the M7AC?

ashen mantle
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toolkit rc 100 - 240v

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1.5A

sullen shadow
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100W or 180W?

ashen mantle
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ill find thelink now

muted sandal
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Does a parallel board balance all the cells while charging?

ashen mantle
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i think yes but im not too sure

sullen shadow
ashen mantle
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the link is sending a picture

sullen shadow
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the cells of the individual batteries equalise with each other when plugged in, but the charger does the balancing @muted sandal

sullen shadow
muted sandal
ashen mantle
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ToolKitRC ADP-100

muted sandal
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Most chargers are 6S per port

sullen shadow
ashen mantle
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Joshua bardwell has a good one for 50$

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however shipping is expensive as im uk

sullen shadow
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all of the cell #1's are connected together in parallel, all of the #2's are connected together in parallel, etc @muted sandal

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from the point of view of the charger, it's just a much larger 6S

muted sandal
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Oh ok that makes sense

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Thanks

sullen shadow
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@ashen mantle so, you have roughly 100W of charging power available

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You said five 4S batteries. What capacity (mAh)?

ashen mantle
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850

sonic sparrow
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You can charge around 7 at a time with 1C, assuming a 90% charge efficiency

Screenshot_20230404-124634_HiPER_Scientific_Calculator.png
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Or you can charge more than 7 if you are ok with charging slower (so it takes longer, but it's actually slightly better for the batteries)

sullen shadow
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okay
so
5 batteries
0.85Ah => 0.85A current (per battery) charging for 1C speed
4 cells in series
3.7V nominal cell voltage

5 * 0.85A * 4 * 3.7V in W
= 62.9W

Charging five 850mAh 4S batteries in parallel will on average take 62.9W
so you will actually have power to spare

muted sandal
sullen shadow
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is that understandable @ashen mantle ?

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edit: dumbass swapped word

ashen mantle
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yes . so is there a cheap alternative to parallel charging or are they unsafe

sullen shadow
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Parallel boards require a significantly higher level of care and attention

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you should get a good parallel board, not the crappy cheapo ones

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HGLRC Thor is a good example

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It has all of the protections necessary, but it doesn't fix the increased danger

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if one battery fails, it will fail 5x as hard if you have 5 batteries plugged in

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When plugging in batteries, you must make sure that they're on a very similar voltage level

ashen mantle
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is there not any safer boards or is that as good as you can get

sullen shadow
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If you plug a 100% charged battery and a 0% charged battery together into a parallel board, stuff will blow up.

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The fuses should protect you, but.. should

sullen shadow
ashen mantle
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i see and there like 40$ a piece

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ill take a look at the parallel board you mentioned

sonic sparrow
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The Thor and JB ones seem very equivalent in terms of protection. I also use ones without protection (first DIY version), but let's just say I learned my lessons 😉
||Blown up some traces of the balancers, but for me thats a minor issue. But it could've been the batteries that exploded which would have been bad||
There is one that is basically a complete charger in itself, but that's even more expensive. I forgot the name

ashen mantle
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yeah my budget is roughly 50 including shipping so that'd be out of my range

sullen shadow
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parallel board and a lipo checker

ashen mantle
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whats a lipo checker isnt that what my charger does ?

sonic sparrow
sullen shadow
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I mean, it's something that everyone should have in their arsenal of tools

sonic sparrow
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The checker is basically only good if you want to check batteries you are not currently charging

sullen shadow
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and imo using the charger as a checker is a pain

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too big and unwieldy

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@ashen mantle You need to check the battery voltage before plugging it into the parallel board

ashen mantle
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ill get one of them too as ill be using my charger to charge so should come in handy

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yes they all need to be within 0.1 of eachother right ?

sonic sparrow
sullen shadow
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within 0.1V is ideal

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but you can skirt around that if you understand lipo voltage curves

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the Thor has an integrated discharger

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which makes it a bit less of a pain

sonic sparrow
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I use .05V if I use my unprotected boards. And only plug in the main plug after a minute or so if they are this far apart

ashen mantle
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yeah my knowledge on that stuff is completely lost been out of the hobby for a while so will propably just buy kit that does it for me or makes it easier

sullen shadow
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you want the main plug to carry the bulk of the current

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and the balance to just take care of the single cell differences

sonic sparrow
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I want my batteries to only have a small current when they are adjusting to each other. The life of my batteries is more important to me than the life of by PCBs

sullen shadow
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what matters is the balance plug

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it can't carry as much

sonic sparrow
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Thinner trace = more resistance = less current

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Thinner plug = more resistance = less current

sullen shadow
sonic sparrow
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None of the traces that I blew up so far because of too much current caused by a voltage difference. Only due to wrong polarity (yes, my V1 didn't even have a proper plug 😂 )

sullen shadow
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and if you f* up the voltage difference, you want it to be on the main plug which won't catch on fire as easily

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I'm worried about the tiny JST pins

muted sandal
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Using the balance plug as a current limiter doesn't seem like it would work

sullen shadow
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they're not meant to carry plug in current loads

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not jST..

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the other one..

sonic sparrow
sullen shadow
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or is it JST?

sonic sparrow
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Balancer is JST, yes

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JST is just the brand, but the balancer is called JST-XH

sullen shadow
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yeah I thought it was the other brand for a moment

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too many types lol

sullen shadow
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they can carry that current when they're already plugged in

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but they're not designed to carry on-contact loads

sonic sparrow
sullen shadow
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they wear out much more quickly in that use-case

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and then you end up with one cell not balancing

sonic sparrow
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3 traces blown but not a single black or molten balancer

sullen shadow
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I wouldn't be saying that if I haven't seen it before

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I've had batteries with worn out JSTs

muted sandal
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Parallel charging seems annoying tbh

sullen shadow
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you won't know until it's f*d

sullen shadow
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parallel charging is a huge part of the hobby, but you must understand how it works

muted sandal
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Or just get multiple chargers 😈

sonic sparrow
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nope

sullen shadow
muted sandal
sullen shadow
sonic sparrow
sullen shadow
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¯_(ツ)_/¯

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Though you really don't want to know what my charging setup was kekw

muted sandal
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The S6 would be awesome for field charging

sonic sparrow
sullen shadow
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Turnigy Double-Tap + knockoff B6AC + unprotected parallel board
with the Turnigy powered from croc clips stuffed into a PC PSU molex... the PSU of my running main PC @sonic sparrow

sonic sparrow
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Mimimi bAlAnCe PlUg NoT mEaNt FoR cHaRgInG

sullen shadow
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the molex got uncomfortably hot when running at full power @sonic sparrow

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yeah anyway that charging setup taught me ALL of the lessons

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including how to yeet a battery out of the window

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when the B6AC decided to do like all the B6's do
blow up

muted sandal
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People in another RC discord I'm in are obsessed with the shitty B6 chargers

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They don't stop recommending them to new people and I keep telling them it's bad

sullen shadow
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They're fine until you rely on their balancing circuitry long-term

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the balancing circuitry overheats to death and blows up either the charger or the lipo

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the B6 clones with fans inside are okay. The fan solves this issue.
Without a fan, they always end up failing.

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unless all you charge is NiMH and similar

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no balancing, no explosion

sonic sparrow
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Charger fleet vs parallel charging board fleet

rn_image_picker_lib_temp_50c08749-cd20-4c26-ad5f-504265518361.jpg rn_image_picker_lib_temp_cf04254f-ef6a-4c48-9fc9-3669ec6993f8.jpg
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I have a second one of those V1 boards (the blue board) where I actually soldered on the XT30s

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but I can't find it

sonic sparrow
muted sandal
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This is my charging area lol

IMG20230404051557.jpg
sullen shadow
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B6AC charged a cell to 4.5V and it turned into a spicy pillow

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was not going to f* around and find out

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so I yeeted it. Smoked on impact.

sonic sparrow
sullen shadow
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the charger was happily showing 4.19V

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cause the circuitry could no longer measure more than 4.19V

sonic sparrow
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Can't say I haven't seen a similar thing with the T6 of a friend, but I saw the charging process at 4.23V and cancelled it

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well, the measuring worked

sullen shadow
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I was really happy to have a lipo checker that day

sonic sparrow
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M7 is single channel

grafik.png
sullen shadow
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@sonic sparrow are you confusing elyk and decx_pc?

sonic sparrow
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apparently

sullen shadow
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xD

sonic sparrow
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😂

sullen shadow
sonic sparrow
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Told my friend "no, you don't need to design this part. I'm fine without

rn_image_picker_lib_temp_c764a93b-435d-44ac-aa94-b83cfa339c00.jpg
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except this permanently plugged in PSU is a fire hazard

  • Rated for 400W, can only sustain 180ish
  • poor factory grounding
  • breaks down immediately if you draw more than 350W
  • breaks down briefly every now and then if you draw more than 250W
  • gets hot, smelly and drops the voltage to around 18V if you draw more than 180W continuously without active cooling (at which point I just stop charging so the PSU can cool down a bit
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And yes, this PSU is always next to some chonky LiPos that can help the fire grow 🙂

sullen shadow
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It's not a psu, it's a FSU - fire starter unit.