Dual Battery Mod

[chazz]

I'm no Lipo expert but If anyone was thinking of taking apart a dji battery and just using the cells i wouldn't waste your time...The total pack resistance is 88 milliOhm...Each Cell is over 21milliOhm...from everything i read on lipos they are considered junk at 20...They have a low C rating too.. i guess that's why they're so light...I don't think it will be good for an external...

 

[chazz]

Has anyone ever attempted this with success? I'm thinking i'm goin to hook up a MS8 battery to this...

 

[chazz]

didn't fly it yet but the motors start with no battery errors. shows full voltage but the capacity (mah) doesn't match the ms8 battery i have plugged into it . i guess there's a program limit to what it displays but hopefully it doesn't matter...and here's what its looks like with 2 ms8lihv's attached,,,I guess we'll see

 

[Digdat0]

Has anyone ever attempted this with success? I'm thinking i'm goin to hook up a MS8 battery to this...

**** chazz, your making me wanna take another stab at this. i never did fly mine, its super touchy! Post up a vid if you do man! that thing looks like a beast btw

 

[makaiattila]

i need a help please send me a link to buy a same pcb or while to deblock or reset the pcb when locked on error

 

[Alan Russel]

chazz.or digdat..need advice I accidently cut 3 balance charging wires on my ms 5200 oops..thought about trying to re solder them but don't know how safe that is ? what do you think
the best way to go here or is beyond repair. thanks

 

[Digdat0]

chazz.or digdat..need advice I accidently cut 3 balance charging wires on my ms 5200 oops..thought about trying to re solder them but don't know how safe that is ? what do you think
the best way to go here or is beyond repair. thanksView attachment 82514

I'd resolder that, should be fine.

 

[makaiattila]

chazz.or digdat..need advice I accidently cut 3 balance charging wires on my ms 5200 oops..thought about trying to re solder them but don't know how safe that is ? what do you think
the best way to go here or is beyond repair. thanksView attachment 82514

Repair with contracting tubes and you atention with short circuiting

 

[chazz]

chazz.or digdat..need advice I accidently cut 3 balance charging wires on my ms 5200 oops..thought about trying to re solder them but don't know how safe that is ? what do you think
the best way to go here or is beyond repair. thanksView attachment 82514

I agree with Dig and mak i would solder them.. you don't want any of them to touch each other or bump them with the solder iron or wire strippers accidentally while your working on the other...The sparks and pop will def scare the crap out of ya trust me....And do it with the battery on its side you don't want solder getting on the battery...

Don't know if you wanted this much detail but I'm bored again so here ya go...

1: tape two of them your not working on separately so not to touch by accident
2: strip the insulation off the one you're going to work on first
3: tin the ends
4: slide shrink tube on the wire (sometimes i forget this and it pisses me off)
5: solder the wires
6: let it cool before sliding the shrink tube back over the joint
7: slide the shrink tube down over the joint and heat it with a heat gun or lighter..
8: on to the next...

If i missed something someone will chime in I'm sure...

 

[chazz]

ok so i tested it...Lots of things learned and needed to learn... whether its worth pursuing or not idk yet...
First thing if your ever going to try this is don't do what i did and strap 2 8s to it on your trial run and just fly like normal. my second flight was more cautious with one split 8 getting 32-1/2 min...the mah that it thinks it has and what you actually have is an issue because apparently that's what it uses to calculate percentage of battery you have left...Also Memory and programming in the chip is an issue. Right now i'm in the process of trying to drain the capacitors so it forgets how much mah it has..you cant just pay attention to battery percentage to tell you when to land you have to watch your battery voltage to gauge when to land.... Honestly Its really a little difficult for me to explain this thing but I'm still testing...

 

[chazz]

the above post probably doesn't make sense to most but i think that's normal because it doesn't really to me either...The whole thing is very confusing on how it actually works and to actually get good time with this thing and if its any better then the stock battery, MS8 and MS6.6 combined....

I mean when i attach this battery thing it changes what my FW say it is in the djgo app...when this is attached i have 1.05+, with a reg stock batt its 1.07..that's an example of how glitchy this thing is...

 

[chazz]

 

[Digdat0]

the above post probably doesn't make sense to most but i think that's normal because it doesn't really to me either...The whole thing is very confusing on how it actually works and to actually get good time with this thing and if its any better then the stock battery, MS8 and MS6.6 combined....

I mean when i attach this battery thing it changes what my FW say it is in the djgo app...when this is attached i have 1.05+, with a reg stock batt its 1.07..that's an example of how glitchy this thing is...

dude thats gonna be the longest fligher EVER! 45 miles each way chazz!

are you using a DJI board or a 3rd party board? I used a DJI one, and i found that MAH would show random stuff, but sometimes if i used my 4.0 or 2300 it would show the right mah. Battery % worked fine independant of that, as did the voltage. Thats weird it changes the version on you though, that makes no sense .. all you did was change the cells its connected to not the board.

If anyone wants to do this, older batteries work great. for a minimal investment of like $40 you too can play with this mod! Theres a good seller on ebay if you offer $40 a battery you are good to go. They are all authentic. (I dont know that guy just buy alot from him). I need to get one myself just for this reason. @dirtybum you gots parts, when you gonna try this mod?

 

[k9time]

Dig I'm running twin 2300's and twin 3400's venom bats. What voltage can I rum them down to? When I come in i put a voltage checker on them and they are usually about 15.1 total volts. Can I run them again or time to charge? Thanks

 

[chazz]

dude thats gonna be the longest fligher EVER! 45 miles each way chazz!

are you using a DJI board or a 3rd party board? I used a DJI one, and i found that MAH would show random stuff, but sometimes if i used my 4.0 or 2300 it would show the right mah. Battery % worked fine independant of that, as did the voltage. Thats weird it changes the version on you though, that makes no sense .. all you did was change the cells its connected to not the board.

If anyone wants to do this, older batteries work great. for a minimal investment of like $40 you too can play with this mod! Theres a good seller on ebay if you offer $40 a battery you are good to go. They are all authentic. (I dont know that guy just buy alot from him). I need to get one myself just for this reason. @dirtybum you gots parts, when you gonna try this mod?

Hey dig i want you to start this too! i need help figurin this thing out....And thanks or the link i'm buyin another..

But here’s the thing Dig, I did modify the board a little. Maybe I should have started with that. When I did my first test flight I noticed the battery percentage on the djigo app was dropping fast and noticed my voltage wasn’t dropping at the same rate, it was dropping slower…for example you might think at 50% battery left you would be at 2240 MAH remaining (half the total capacity of the dji battery) and the volts may be at something like 3.7 volts per cell (maybe half of the useful volts)…my first test was to 50% with 2240mah remaining which seems logical but the volts per cell were at around 3.97vpc (87% left)…If would have kept flying to 0% battery the mah would have been displaying 0 and the volts would have been at let’s say 3.7V which is close to where it is with 50%v remaining… There would have been a lot of juice left in the battery but you know the DJI programming makes you land at 10% so it wouldn’t have let me use up the volts… in theory I would have had 3520 mah left. (8000 – 4480)… It was like running the stock 4480mah battery with the weight of the MS8…

I remembered reading somewhere maybe in this thread IDK but when they worked with the original battery mod (keeping the cells and soldering leads to the board) there was 2 different areas you can solder the leads to…”before the chip” or “after the chip” (I made that terminology up they said something else)…”Before the chip” sucked and they weren’t getting good time but soldering “after the chip” fixed this.. I have to believe that the voltage running through the chips calculates the capacity used (mah) somehow and the program has a limit of 4480 which it uses to figure out the battery percentage…So my first try I re-positioned the leads to “after the chip” but it would error with the “not official battery thing” or something like that…So I decided to solder them back to the original position “before the chip” and put jumper leads around to “after the chip” ...after doing this I was able to run my battery down to 3.35vpc before it came up with an motor overload and made me land…so I had a choice either longer flight time (jumpers in) or battery percentage that make me land to early (jumpers out)…

If you would use a battery around the 4480 mah range it should work…but for some reason I like to be tormented and I’m stickin to tryin somthin bigger…

 

[dan84uk]

Im using a standard, but after trying countless ways of mounting the multistar, ive settled on this.

Before i tried pushing the camera forward as some others have, but it induced camera vibration at high speed which was unacceptable, hanging the battery off the back, makes handling clumsy, and motors noisy trying to compensate. its now perfectly balanced and the video is spot on even at full speed, its also seems more resistant to the wind than stock prob due to the weight. I now plan to mount the battery inside a 40mm project box, so its easy to swap in and out.

 

[Digdat0]

Im using a standard, but after trying countless ways of mounting the multistar, ive settled on this.

Before i tried pushing the camera forward as some others have, but it induced camera vibration at high speed which was unacceptable, hanging the battery off the back, makes handling clumsy, and motors noisy trying to compensate. its now perfectly balanced and the video is spot on even at full speed, its also seems more resistant to the wind than stock prob due to the weight. I now plan to mount the battery inside a 40mm project box, so its easy to swap in and out.

that looks really good!! those tall landing gear are really needed, but it looks pretty clean! Is the camera attached with duallock or other means? thats awesome!

 

[Digdat0]

Hey dig i want you to start this too! i need help figurin this thing out....And thanks or the link i'm buyin another..

But here’s the thing Dig, I did modify the board a little. Maybe I should have started with that. When I did my first test flight I noticed the battery percentage on the djigo app was dropping fast and noticed my voltage wasn’t dropping at the same rate, it was dropping slower…for example you might think at 50% battery left you would be at 2240 MAH remaining (half the total capacity of the dji battery) and the volts may be at something like 3.7 volts per cell (maybe half of the useful volts)…my first test was to 50% with 2240mah remaining which seems logical but the volts per cell were at around 3.97vpc (87% left)…If would have kept flying to 0% battery the mah would have been displaying 0 and the volts would have been at let’s say 3.7V which is close to where it is with 50%v remaining… There would have been a lot of juice left in the battery but you know the DJI programming makes you land at 10% so it wouldn’t have let me use up the volts… in theory I would have had 3520 mah left. (8000 – 4480)… It was like running the stock 4480mah battery with the weight of the MS8…

I remembered reading somewhere maybe in this thread IDK but when they worked with the original battery mod (keeping the cells and soldering leads to the board) there was 2 different areas you can solder the leads to…”before the chip” or “after the chip” (I made that terminology up they said something else)…”Before the chip” sucked and they weren’t getting good time but soldering “after the chip” fixed this.. I have to believe that the voltage running through the chips calculates the capacity used (mah) somehow and the program has a limit of 4480 which it uses to figure out the battery percentage…So my first try I re-positioned the leads to “after the chip” but it would error with the “not official battery thing” or something like that…So I decided to solder them back to the original position “before the chip” and put jumper leads around to “after the chip” ...after doing this I was able to run my battery down to 3.35vpc before it came up with an motor overload and made me land…so I had a choice either longer flight time (jumpers in) or battery percentage that make me land to early (jumpers out)…

If you would use a battery around the 4480 mah range it should work…but for some reason I like to be tormented and I’m stickin to tryin somthin bigger…

ahhhh okay i get ya. All my tries i was working on the middle of the board, the after the chip, part as you call it. (I think its switched and unswitched?). Its odd that just moving the lines from one to the other caused the not offical battery thing, but DJI has some weird programming. I recall one guy much earlier in the thread cursing the DJI engineers for how they build the smart board I will try and order some parts to play around here I need more xt60 power lines and a battery.

 

[dan84uk]

that looks really good!! those tall landing gear are really needed, but it looks pretty clean! Is the camera attached with duallock or other means? thats awesome!

The battery is stuck on with ultra strength velcro, the camera 3m moulding foam tape, the stuff used to stick trim to cars, amazing stuff. Once the enclosure for the battery is here it will all be trim/moulding tape. I can then buy more multistars and slide them in. Im really happy now that it flys perfectly, i tried so many arrangements, but it never handled or performed as good as stock. An extra added bonus is that i dont get the probs in shot either

 

[chazz]

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