Battery Mod Info

[damoncooper]

Cheers Damon. Before I start ordering stuff, do you think this way of doing the mod will actually increase my flight time or are the P2 batts too heavy at 360g each?

You will definitely get extra flight time and extra protection from main battery shutdown. The weight is very good. Neil Watts' dual battery mount (link on first page) should work for these.

I have a P2 gathering dust myself I may give a go at using its batteries as aux for the Inspire,

Good idea!

 

[Lew40]

You will definitely get extra flight time and extra protection from main battery shutdown. The weight is very good. Neil Watts' dual battery mount (link on first page) should work for these.

I have a P2 gathering dust myself I may give a go at using its batteries as aux for the Inspire,

Good idea!

Cool. Another question I have is - I only have the 1 batt for the Inspire. If I done this mod would I be able to just change the P2 batts when the TB47 has lost its power? Thinking about it, the fresh P2 batts would try and charge the TB47 up.

 

[damoncooper]

Cool. Another question I have is - I only have the 1 batt for the Inspire. If I done this mod would I be able to just change the P2 batts when the TB47 has lost its power? Thinking about it, the fresh P2 batts would try and charge the TB47 up.

Yes, but what happens is the two 3S batteries when wired together in series, form a "virtual" 5700mah 6S battery that puts out 22.2V, which is what the Inspire needs.

The "virtual" 6S battery you have created then gets plugged into the main DJI battery using this battery mod in a way that makes your external "virtual 6S" battery connect "in parallel". That just means they now form one single "virtual" battery that the Inspire can draw power from.

As that happens, the batteries discharge more or less evenly so if you have matched the Inspire battery capacity with your external battery capacity, you end up with longer flight time but all batteries will discharged to more or less the same level at the end of the flight.

So to fly again you'd want to pop in another freshly charged Inspire battery and connect two freshly charged external batteries.

You CAN just replace the external batteries for freshly charged ones, and they will charge the main in flight BUT I would strongly advise against it with low C (low discharge rated) batteries such as DJI or Multistar 10C batteries. You will overload those batteries as both the aircraft and Inspire battery demand current from them and you risk serious problems.

At least 25C I think if you wanted to do that. Guys here have done what you have said to squeeze extra flight time off a mostly depleted Inspire battery but don't do it with low C batteries.

Hope that helps.

 

[damoncooper]

PS I did find this little number online that could be used as part of your solution. Get two of these, add an XT60 connector to where the banana plugs are, and plug both into a XT60 series connector cable. That then plugs into your plug coming out of your modified Inspire battery.

Jet.com

 

[Lew40]

PS I did find this little number online that could be used as part of your solution. Get two of these, add an XT60 connector to where the banana plugs are, and plug both into a XT60 series connector cable. That then plugs into your plug coming out of your modified Inspire battery.

Jet.com

View attachment 6218

Cheers. I'll start ordering

 

[dellycem]

 

[dellycem]

 

[dellycem]

 

[damoncooper]

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So. Does it work?

 

[dellycem]

Yep, working. Align battery used just to test, I have some other stuff to try on.

 

[damoncooper]

Yep, working. Align battery used just to test, I have some other stuff to try on.

Can you say more about the experience of cell replacement and what your personal goals are?

 

[dellycem]

First of all I would not suggest anybody to dismantle a swelled battery, more risky to rip the foil when tearing apart from each other because they are too puffy.

My goal was to have a original batt cap with a balance connector and main output, which will be useful to test lots of alternative batteries.

I saw VCC, GROUND, RX, TX solder points on the circuit; I think it can be connected to a computer with TTL-USB

I am planning to access the main circuit to re-program it's pre-programmed capacity (4500 for TB47 or 5700 for TB48) to higher amounts.

Because these circuit is calculating the remaining percentage amount with measuring the amp flow when in use, so it will not matter even you connect 10000mah full charged. Because the circuit will inform AC as battery finished when 5000mah passes through.

What I need is somebody to help me out for reverse engineering this circuit because it is not all about connecting through TTL, we need to find out how to reprogram.

 

[damoncooper]

I am planning to access the main circuit to re-program it's pre-programmed capacity (4500 for TB47 or 5700 for TB48) to higher amounts.

Because these circuit is calculating the remaining percentage amount with measuring the amp flow when in use, so it will not matter even you connect 10000mah full charged. Because the circuit will inform AC as battery finished when 5000mah passes through.

That's not strictly necessary to use all capacity, though, as the logic isn't a meter that measures voltage as it passes through, but rather an estimate of mah capacity remaining based on current battery voltage.

Witness the operation of the "virtual" 11,100 battery created by the parallel connection of a TB48 and two 2700mH 6S batteries. From the battery logic board's perspective, it's still a 5700mah battery but it just drains "curiously slowly", since it's output is augmented by the external batteries. Flight time is extended and Flight TIME remaining is actually pretty accurate based on voltage in my experience. And when 10%, say of 5700 remains in main battery, that's what's left in the aux as well, assuming matched capacity, since they discharge at the same rate.

It's voltage, then, not metering that determines remaining capacity.

So, you should be good to go if utilization of your new cells is the goal and you've properly rewired the balance lead and temp sensor.

Unless you are really wanting an accurate app capacity available display, which I think may be a tough nut to crack with reprogramming the board.

 

[dellycem]

The circuit is not measuring the voltage passing through, it is measuring the amperage and it does it when charging and when discharging in use.

It is calculating and keeping as a log inside, and showing you the values calculated from the last log created when battery used or charged. There is a design capacity preprogrammed by factory and capacity amount which is calculated by amper flow every charge or discharge. Whatever you do the capacity amount will not pass the design capacity amount because they programmed it that way to keep the battery and consumers safe. The design capacity is the key, this is what we need to reprogram.

You are gaining time when using parallel connected batteries because that out coming batteries helping out the inner original battery to keep up and fight more and easier, thats the thing.

Believe me you can achive more if this logic board is bypassed or hacked.

 

[tcchow]

The circuit is not measuring the voltage passing through, it is measuring the amperage and it does it when charging and when discharging in use.

It is calculating and keeping as a log inside, and showing you the values calculated from the last log created when battery used or charged. There is a design capacity preprogrammed by factory and capacity amount which is calculated by amper flow every charge or discharge. Whatever you do the capacity amount will not pass the design capacity amount because they programmed it that way to keep the battery and consumers safe. The design capacity is the key, this is what we need to reprogram.

You are gaining time when using parallel connected batteries because that out coming batteries helping out the inner original battery to keep up and fight more and easier, thats the thing.

Believe me you can achive more if this logic board is bypassed or hacked.

You are doing it on the right track but the battery compartment will be the issue when you replacing new larger mah battery to use with the board.

 

[dellycem]

You are doing it on the right track but the battery compartment will be the issue when you replacing new larger mah battery to use with the board.

What made you think that I am going to use that space

 

[damoncooper]

The circuit is not measuring the voltage passing through, it is measuring the amperage and it does it when charging and when discharging in use.

It is calculating and keeping as a log inside, and showing you the values calculated from the last log created when battery used or charged. There is a design capacity preprogrammed by factory and capacity amount which is calculated by amper flow every charge or discharge. Whatever you do the capacity amount will not pass the design capacity amount because they programmed it that way to keep the battery and consumers safe. The design capacity is the key, this is what we need to reprogram.

You are gaining time when using parallel connected batteries because that out coming batteries helping out the inner original battery to keep up and fight more and easier, thats the thing.

Believe me you can achive more if this logic board is bypassed or hacked.

I agree there's a designed capacity limit but I don't believe amperage used is used to calculate capacity remaining. I believe capacity remaining is simply based on voltage measured and the assumption that it's a 4500 or 5700mah battery (- some capacity tax DJI calculates based on usage).

A friend of mine is designing a commercial replacement that's larger in mah and although I have nothing to do with that effort, he has done a cell replacement in his testing and stated that a TB47 or 48 board doesn't matter when doing a cell replacement. It's voltage that's used to calculate remaining capacity.

But.

Time will tell!

Have you been able to fly your modified battery yet? Any observations?

 

[dellycem]

I agree there's a designed capacity limit but I don't believe amperage used is used to calculate capacity remaining. I believe capacity remaining is simply based on voltage measured and the assumption that it's a 4500 or 5700mah battery (- some capacity tax DJI calculates based on usage).

A friend of mine is designing in a commercial replacement that's larger in mah and although I have nothing to do with that effort, he has done a cell replacement in his testing and stated that a TB47 or 48 board doesn't matter, since it's voltage that's used to calculate remaining capacity.

But.

Time will tell!

Have you been able to fly your modified battery yet? Any observations?

It is raining/snowing here but tomorrow I am planning to make a test flight inside garage.

 

[tcchow]

What made you think that I am going to use that space

So you intent to leave the battrey compartment emty and mount the battery somewhere else ?

 

[dellycem]

So you intent to leave the battrey compartment emty and mount the battery somewhere else ?

The volume of the the original battery slot can allow maybe up to 6000-6500mah battery to be fitted inside in nowadays LiPo technology.

I am intending to use several packs bigger, so that space has no use for me.