Dual Battery Mod

[Digdat0]

WHY DO THE EXTERNALS NOT EXPLODE AFTER SOME CHARGING TIME?
(next problem: if you connect the balance leads from the dji batt to the externals balance connector
while the externals are empty and the dji bat is full or the other way around,
the cells of the fuller bat will immediately start "charging" the cells ot the emptier one
through the balance leads without any electronics with an extreme current, only limited by the wire resistance, so you are not supposed to do that, or what?)
do i missunderstand any terminology, isnt it true that the SWITCHED SIDE of the smartboard solder joints is directly connected, without any electronics in between, to the dji bat plug ? is there a tiny diode somewhere?

i had to get some more coffee and re-read that, honestly i dont know why the power doesnt go back to the externals, or why it doesnt overload. That part of electrical engineering is past me man! I just know it works, maybe someone more technical can help answer that question

 

[dirtybum]

View attachment 65522

Hey digdat0 have tested these TP batteries did not get the fly time I had hoped for.30 mins down to about 8/10%. They have a low C rating at max discharge 10C this is to low.other wise they would have been a good choice.going to be sending them back.

Hey silver, I also tested a few different capacities of these thunder powers a while back, I was also hopeful for them, and I was also disappointed. The problem I found with all the ones I've tested was that when I ran the main battery down to 0 to 5% the thunder powers still had approximately 30% capacity left. I don't think that's an issue of the 10C discharge rating, The multi stars have a 10C rating and they burn down evenly with the DJI battery.
So it's not that these couldn't offer good flight time, rather that you're just left with too much fuel in the externals. It's too bad because they're very light batteries. One thing you could do and I haven't tested this yet, is ignore the fact that your app says 0% and continue to fly home and it's a possibility that you can still go a couple miles on zero. But like I said I wasn't quite ready to be that guinea pig yet


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[dirtybum]

Hey silver did your thunder powers come with a 5C balance plug?


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[petermeter]

i had to get some more coffee and re-read that, honestly i dont know why the power doesnt go back to the externals, or why it doesnt overload. That part of electrical engineering is past me man! I just know it works, maybe someone more technical can help answer that question

next time i make diagram.

when my dji batt gets weak, i will open it and find out and may post here.

 

[petermeter]

The multi stars have a 10C rating and they burn down evenly with the DJI battery.

thats obviosly because of a approx. matching internal resistance,
and/or cable resistance.

 

[Silverwingflinx]

Hey silver, I also tested a few different capacities of these thunder powers a while back, I was also hopeful for them, and I was also disappointed. The problem I found with all the ones I've tested was that when I ran the main battery down to 0 to 5% the thunder powers still had approximately 30% capacity left. I don't think that's an issue of the 10C discharge rating, The multi stars have a 10C rating and they burn down evenly with the DJI battery.
So it's not that these couldn't offer good flight time, rather that you're just left with too much fuel in the externals. It's too bad because they're very light batteries. One thing you could do and I haven't tested this yet, is ignore the fact that your app says 0% and continue to fly home and it's a possibility that you can still go a couple miles on zero. But like I said I wasn't quite ready to be that guinea pig yet


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Hey DB yes I was thinking the same thing even when the dji app hit 0% to keep flying.but I to did not want to test that theory.and risk the chance of over discharge on the TP and drawing to much power under load.yes I had to plug the balance lead into the 5C port! Then It got me thinking now do I need to buy the TP charger to fully charge the TP batts??these batteries are less then 10C that's max burst.the MS are rated 10c constant with maxx burst of 20c.

 

[Digdat0]

next time i make diagram.

when my dji batt gets weak, i will open it and find out and may post here.

I can post pics of the smart board if you want, I have an extra one which is fried I can take some closeup pics of.

 

[petermeter]

I can post pics of the smart board if you want, I have an extra one which is fried I can take some closeup pics of.

thanks, but i have to see that myself in reality, and i never disassembled a dj battery so this will be interesting..

 

[chazz]

Looking for bits for my battery mod i found this on ebay

Anyone used something like this??

Looks simple as to make from the pics.. not sure how much i trust it shorting ?

I bought it and works great... 2 flights in and last flight was a little over 30 min with the 5200 split...Nothing heats up and seems fine as long as you don't hook up the lipo before you install the thing I don't see an issue with shorting...I ordered the Multistar 5200 to see how that goes...Not real sure how I'm going to mount the single bat to the quad...Sure beats having to use a modded battery...I can switch this thing from battery to battery...

 

[Digdat0]

I bought it and works great... 2 flights in and last flight was a little over 30 min with the 5200 split...Nothing heats up and seems fine as long as you don't hook up the lipo before you install the thing I don't see an issue with shorting...I ordered the Multistar 5200 to see how that goes...Not real sure how I'm going to mount the single bat to the quad...Sure beats having to use a modded battery...I can switch this thing from battery to battery...

You will need dual lock and mount under the Vps. I'd be worried about an arc between the two leads.

 

[chazz]

You will need dual lock and mount under the Vps. I'd be worried about an arc between the two leads.

Do you mean like flash over or the leads actually touching? At the nearest point they are approx 2mm apart...I'm no electrician but I think that should be enough distance not to flash or at least it was on the first two flights....Maybe a electronics person can chime in...And if your talking about touching they are held apart by the battery ports (If that's what there called) and there's no power there until the battery is switched...

I'm starting to sound like I'm trying to sell this thing and I'm really not...to each his own...It's just right for a lazy guy like me...

This dual Lock stuff, is that the 3m Velcro type stuff?

 

[shockwave199]

I bought it and works great... 2 flights in and last flight was a little over 30 min with the 5200 split...Nothing heats up and seems fine as long as you don't hook up the lipo before you install the thing I don't see an issue with shorting...I ordered the Multistar 5200 to see how that goes...Not real sure how I'm going to mount the single bat to the quad...Sure beats having to use a modded battery...I can switch this thing from battery to battery...

That adapter piece looks very slick. Keep posting your findings using that one. I would recommend the the MS 5200 split for the externals, not a single, for better loading balance. I've read a single battery makes for instability on take off and landing. Always load the weight as well balanced as you can, especially with these heavy batteries.

 

[petermeter]

That adapter piece looks very slick. Keep posting your findings using that one. I would recommend the the MS 5200 split for the externals, not a single, for better loading balance. I've read a single battery makes for instability on take off and landing. Always load the weight as well balanced as you can, especially with these heavy batteries.

but dont split with an axe

 

[shockwave199]

but dont split with an axe

Or what, you end up like your avatar?

 

[petermeter]

Or what, you end up like your avatar?

 

[Digdat0]

BTW guys - i've been compiling a spreadsheet of compatible lipo/lihv batteries with weight, cost and links to buy. thought you guys may find it useful, its open to editing so feel free to add any you come across which i missed.

Lipo/LIHV Battery Inventory List (4s)

looks like this, should be a useful tool

 

[petermeter]

BTW guys - i've been compiling a spreadsheet of compatible lipo/lihv batteries with weight, cost and links to buy. thought you guys may find it useful, its open to editing so feel free to add any you come across which i missed.

Lipo/LIHV Battery Inventory List (4s)

looks like this, should be a useful tool

looks good!
so the multistar 4000 lipo ist better than the multistar 4000 liHV? or does the HV bonus,
and less voltage drop at the end make the livh better (actual flight time per weigt)?

 

[Silverwingflinx]

Hey silver, I also tested a few different capacities of these thunder powers a while back, I was also hopeful for them, and I was also disappointed. The problem I found with all the ones I've tested was that when I ran the main battery down to 0 to 5% the thunder powers still had approximately 30% capacity left. I don't think that's an issue of the 10C discharge rating, The multi stars have a 10C rating and they burn down evenly with the DJI battery.
So it's not that these couldn't offer good flight time, rather that you're just left with too much fuel in the externals. It's too bad because they're very light batteries. One thing you could do and I haven't tested this yet, is ignore the fact that your app says 0% and continue to fly home and it's a possibility that you can still go a couple miles on zero. But like I said I wasn't quite ready to be that guinea pig yet


Sent from my iPhone using PhantomPilots

Hey DB today I tested our theory on those thunder power batts at 0% dji battery I still flew it for 2 mins! Dji battery Has 4293 mah 47 charges was dipping down to 3.14 volts per cell batt temp 51C.the thunder power land volt 14.8v 3.70 per cell there still could have been a little more time YET!! At this point it was only 30 mins that's just not good oh well back to the drawing board!! I hope I did not damage the dji battery???

 

[Silverwingflinx]

BTW guys - i've been compiling a spreadsheet of compatible lipo/lihv batteries with weight, cost and links to buy. thought you guys may find it useful, its open to editing so feel free to add any you come across which i missed.

Lipo/LIHV Battery Inventory List (4s)
.
looks like this, should be a useful tool

Hey digdat0 just posted EXTrem flite test with those TP batts but still only 30 min flight! Those were the 3500 mah HV

 

[Digdat0]

looks good!
so the multistar 4000 lipo ist better than the multistar 4000 liHV? or does the HV bonus,
and less voltage drop at the end make the livh better (actual flight time per weigt)?

ya know im not sure, technically you get more volts but .. if the mah is the same, is there a benefit?