Dual Battery Mod

[Ed209]

Well that's is something modded it to main board Dji batt is 50% and the multi stars are about 60% and it still wants to charge it hhhhmmmm!!

Huh?

 

[Silverwingflinx]

Huh?

That's what I thought???

 

[Digdat0]

Well that's is something modded it to main board Dji batt is 50% and the multi stars are about 60% and it still wants to charge it hhhhmmmm!!

You did the power mod to the main board and you still encounter the battery charge issue?

 

[Ed209]

That's what I thought???

I'm not following you.

 

[dirtybum]

If you start out with the dead main battery and fully charged externals you're still going to have problems, I can't say that it's going to start charging the battery, because I've never ran that test. But if you're DJI battery goes completely dead, you will receive battery errors at least, which will cause and an autoland situation

 

[Silverwingflinx]

You did the power mod to the main board and you still encounter the battery charge issue?

Yes it started the charging process,tonight I went to fly and had fully charged batts and it happened again ?? It started to charge landed turn Dji batt back on then it was fine!

 

[Silverwingflinx]

I'm not following you.

 

[Silverwingflinx]

I did the main board battery mod after I was done I wanted to test it,so I put a half charged Dji batt in then I hooked up the multistar batt I believe it was just over half charged.when I did that it started to charge.also I had fully charged batts and it did the same thing.

 

[Ed209]

I did the main board battery mod after I was done I wanted to test it,so I put a half charged Dji batt in then I hooked up the multistar batt I believe it was just over half charged.when I did that it started to charge.also I had fully charged batts and it did the same thing.

I haven't tried anything except fully charged externals and DJI battery. I have not had any issues and I would estimate I've got around 30-40 flights spread across 3 different P3 model (P3S, P3A, P3P). It may be possible that if there is a big voltage difference between the external and the DJI battery that it will try and charge. In my experience, it seems that with the regular battery mod (modded DJI battery), even a voltage difference of .03v would start the charging of the DJI battery. I wouldn't compare battery % because that is not an actual measurement per say. Voltage is how I look at it. So what I'm saying is sometimes I would power up and see lowest DJI cell voltage is 4.31 whereas the external would be 4.35. Even that tiny difference would start making the DJI battery go into charging.

This is how batteries behave when connected in parallel. It becomes one giant battery and with ANY deviations between ALL of the cells, the battery tries to equalize the voltages across ALL cells. This is why it is important to start with fully charged batteries; you want to minimize this.

 

[Silverwingflinx]

Yes I a

I haven't tried anything except fully charged externals and DJI battery. I have not had any issues and I would estimate I've got around 30-40 flights spread across 3 different P3 model (P3S, P3A, P3P). It may be possible that if there is a big voltage difference between the external and the DJI battery that it will try and charge. In my experience, it seems that with the regular battery mod (modded DJI battery), even a voltage difference of .03v would start the charging of the DJI battery. I wouldn't compare battery % because that is not an actual measurement per say. Voltage is how I look at it. So what I'm saying is sometimes I would power up and see lowest DJI cell voltage is 4.31 whereas the external would be 4.35. Even that tiny difference would start making the DJI battery go into charging.

This is how batteries behave when connected in parallel. It becomes one giant battery and with ANY deviations between ALL of the cells, the battery tries to equalize the voltages across ALL cells. This is why it is important to start with fully charged batteries; you want to minimize this.

yes I agree also the amount of charges on each Dji battery I did the main board mod to see if I could get better flite times less resistance not putting power into the Dji battery but it seems to be the same fly time?

 

[Ed209]

Same flight times as the battery mod. But for me, better piece of mind, simplified, and no need to mod any new batteries I purchase.

 

[shockwave199]

I haven't tried anything except fully charged externals and DJI battery. I have not had any issues and I would estimate I've got around 30-40 flights spread across 3 different P3 model (P3S, P3A, P3P). It may be possible that if there is a big voltage difference between the external and the DJI battery that it will try and charge. In my experience, it seems that with the regular battery mod (modded DJI battery), even a voltage difference of .03v would start the charging of the DJI battery. I wouldn't compare battery % because that is not an actual measurement per say. Voltage is how I look at it. So what I'm saying is sometimes I would power up and see lowest DJI cell voltage is 4.31 whereas the external would be 4.35. Even that tiny difference would start making the DJI battery go into charging.

This is how batteries behave when connected in parallel. It becomes one giant battery and with ANY deviations between ALL of the cells, the battery tries to equalize the voltages across ALL cells. This is why it is important to start with fully charged batteries; you want to minimize this.

Than would it not make sense to charge the splits just a bit less than full to help the problem? If I start with a full dji mod battery and charge the 5200's to say, 4.3 or even a little less, could that help to avoid the situation? That's counter to you guys squeezing out every bit for long distance flight but for me if it meant the difference between 29 minutes or 28 and not having to worry about the dji battery going into charge mode, I'd opt for slightly less fly time. Make sense at all?

 

[dirtybum]

Not only does it make sense, but I have to do that with the P4! I found on the P4 charging the externals to 4.32 is the magic number. I rarely have problems with the P3 going into charge mode, I try to take off within 20 seconds of plugging the externals in, on the P3 if I can get it off the ground to hover, i've never had a start blinking once in the air

 

[Ed209]

Than would it not make sense to charge the splits just a bit less than full to help the problem? If I start with a full dji mod battery and charge the 5200's to say, 4.3 or even a little less, could that help to avoid the situation? That's counter to you guys squeezing out every bit for long distance flight but for me if it meant the difference between 29 minutes or 28 and not having to worry about the dji battery going into charge mode, I'd opt for slightly less fly time. Make sense at all?

Yeah that should work. The key is getting the voltages close enough. Seems like db found the right voltage with the P4. Not sure what the threshold is with the DJI battery board where it says "OH, I AM CHARGING".

Not only does it make sense, but I have to do that with the P4! I found on the P4 charging the externals to 4.32 is the magic number. I rarely have problems with the P3 going into charge mode, I try to take off within 20 seconds of plugging the externals in, on the P3 if I can get it off the ground to hover, i've never had a start blinking once in the air

I don't know why it happened to me so often. I was charging and topping off the DJI battery. I'd check voltage in Go and even with my Horizon modded DJI battery I would check it with a voltage meter directly and still had issues.

 

[dirtybum]

Just got my 6.6 split back from Tom at Midwest horizon.
I originally sent him my 6.6 MultiStar to split because it was just too heavy as a single battery all the way to the rear. So I hadnt anything to lose by having it split.
As a single battery you gave me 39 minutes on the p3S, I only got two flights out of it as a split and it only produced 30 minutes. Then it was way out of balance and wouldn't charge. Tom did a rework and concluded that it might have been a cold solder on one of the aluminum tabs. Those tabs are very fragile and for any of you have that done it, are almost impossible to solder to! He found a solder that was specifically for aluminum and reworked it. I'm hopeful that now maybe I can meet somewhere in the middle of 30 to 39. I'll let ya know.

http://horizonfpvantennas.us/product/6600ah-4s-hi-voltage-power-mod-v3-6/

 

[Ed209]

View attachment 60472
Just got my 6.6 split back from Tom at Midwest horizon.
I originally sent him my 6.6 MultiStar to split because it was just too heavy as a single battery all the way to the rear. So I hadnt anything to lose by having it split.
As a single battery you gave me 39 minutes on the p3S, I only got two flights out of it as a split and it only produced 30 minutes. Then it was way out of balance and wouldn't charge. Tom did a rework and concluded that it might have been a cold solder on one of the aluminum tabs. Those tabs are very fragile and for any of you have that done it, are almost impossible to solder to! He found a solder that was specifically for aluminum and reworked it. I'm hopeful that now maybe I can meet somewhere in the middle of 30 to 39. I'll let you knowhttp://horizonfpvantennas.us/product/6600ah-4s-hi-voltage-power-mod-v3-6/

This is what I use https://www.amazon.com/Harris-500K-Al-Solder-Aluminum-Solder/dp/B001HWFM9Y. The flux that is included with this kit is no joke. If you hold your solder to the tab and don't "cut" it with the iron you will be left with your solder line welded to the tab

 

[dirtybum]

Nice ed, although it seems like it's above my skill level, like you need some real steady hands

 

[Ed209]

Nice ed, although it seems like it's above my skill level, like you need some real steady hands

Well you can't have hangover shakes when soldering lipo tabs but it's not that bad. And from what I've been told, my soldering sucks and yet I've done it a few times

 

[dirtybum]

Only one hater told that!! I seen it and I thought it looked just fine for the application/purpose[emoji41]

 

[dirtybum]

When I hook these splits or any battery for that matter up to my charger and check the resistance, what would be a high number what am I looking for?