Battery Mod Info

[Ardi Wicaksono]

What craft and battery firmware are people using?
I've got my test mule on Inspire on 1.4.10 and the battery calculations are totally incorrect, with a TB48 plus additional cells to give 10,000mAH it's going into low battery autoland with 3.75 - 3.8 volts per cell under load

it flies fine, just isn't doing battery capacity calculations correctly

mine is 1.8.1 iirc, with turnigy 2 x 6s 2650mah 20c and TB48 with around 85% battery life(old battery with 50+ cycles) it hovered around 22 minutes,and light flying gave me 19 minutes to 30%.But i lost the green bar flight range calculation too,but there are flight minutes displayed on the dji go app (it says 25 minutes from the take off moment).The batteries are mounted this way,no flight behaviour differences,motor sounds ok. Oh,dji inspire V1 + x3.

edit : the green bar flight calculation is there,didnt notice it. but does it give me correct calculation as now i have more battery capacity?

 

[Pescatoral Pursuit]

Question:

Is there a significantly reduced lifespan or increased volatility with LiHv batteries that would negate the modest weight savings over standard lipo's?

I have a charger compatible with the lihvs.

 

[Ruckusman]

I'm not sufficiently informed on all of the differences between standard LiPOs versus LiHV, I do believe that there is a slight boost in energy density (not power density as this is governed by the actual C-Rating of a particular battery). This may be speculation BTW.

However is you look at the discharge curves of both types of batteries, the LiHV is steeper, both become exhausted at almost identical voltages.

FWIW batteries with equivalent capacity (truthfully labelled of course ) should perform bascially the same as long as they are used within the parameters of their c-rating

So the only reason to use LiHV supplementary batteries on the Inspire is because the supplied cells would have a higher voltage otherwise, and there would be a sudden high current flow from the LiHV cells to the normal lipo cells - potentially catastrophic!!

Using purely normal Lipo cells, i.e. replacing the Inspire cells with normal Lipos is completely feasible, I've done it on a battery with damaged cells - the Inspire however never shows a 100% charged battery and the battery head unit cannot be used to recharge the cells because it would overcharge normal LiPO cells - potential for explosion etc etc

 

[damoncooper]

I'm not sufficiently informed on all of the differences between standard LiPOs versus LiHV, I do believe that there is a slight boost in energy density (not power density as this is governed by the actual C-Rating of a particular battery). This may be speculation BTW.

However is you look at the discharge curves of both types of batteries, the LiHV is steeper, both become exhausted at almost identical voltages.

FWIW batteries with equivalent capacity (truthfully labelled of course ) should perform bascially the same as long as they are used within the parameters of their c-rating

So the only reason to use LiHV supplementary batteries on the Inspire is because the supplied cells would have a higher voltage otherwise, and there would be a sudden high current flow from the LiHV cells to the normal lipo cells - potentially catastrophic!!

Using purely normal Lipo cells, i.e. replacing the Inspire cells with normal Lipos is completely feasible, I've done it on a battery with damaged cells - the Inspire however never shows a 100% charged battery and the battery head unit cannot be used to recharge the cells because it would overcharge normal LiPO cells - potential for explosion etc etc

The DJI batteries are LiHV. Due to their built in "intelligence" (don't get me started), they will accept charge when the connected external battery is above 25.9V or so, which means the aircraft is powered by the aux battery for a portion of the beginning of the flight until voltage drops and power is drawn from both DJI and aux battery pretty equally.

Absolutely no harm in using LiHV batteries. Flight time and battery % is calculated based on voltage in the DJI battery only so the longer it stays above 10% (forced auto land), the longer your flight time.

 

[Ruckusman]

I know the DJI batteries are LIHV, that's why I said don't use normal LiPo supplementary batteries.

The battery &/or flight controller firmware on version 1.4.10 however doesn't use actual cell voltage to calculate % remaining, I've tried 1.2, 1.3 & 1.4 firmware and experienced autolanding with cell voltages at ~3.75 - ~3.8 volts.
Typically % battery remaining hovers in the high 80% to low 90% for an extended period of time then plummets to below 10% with actual cell voltages still at 3.8 volts or thereabouts. Then the craft goes into autoland.

I've updated to 1.6 firmware to test, I suppose what I've demonstrated is that their battery percentage calculations are complete rubbish in older firmware (we already knew that, just how bad is somewhat shocking).

My effort in stepping forward incrementally is to maintain as much of the faster flight dynamics as possible whilst also getting proper battery calculations based upon cell voltages not some other irrelevant calculation.

I'll postulate that the flight capacity has some sort of time element as it's calculation because with 10,000Mah on board there seems to be a limited flight time with firmware 1.2,v 1.3 & 1.4

 

[Lee Sang Koo]

Anyone know what battery he use, i whant try build mine too
Thanks

I'm making it^^

 

[Pescatoral Pursuit]

90+% of the batteries used in this thread have been standard lipos with the lihvs showing only marginal improvements in flight times. Is there a big problem?

Are the lipos being overcharged initially as the batteries average out until the excess voltage is burned off?

 

[damoncooper]

90+% of the batteries used in this thread have been standard lipos with the lihvs showing only marginal improvements in flight times. Is there a big problem?

Are the lipos being overcharged initially as the batteries average out until the excess voltage is burned off?

The problem is the DJI logic board, frankly. Once you understand how it works you realize how many hoops we have to jump through to double flight time.

For those of you thinking it's impossible to get beyond 30-35min, there is hope

Here's a 49:13 actual flight (vs hover) with an M100 with only a battery mod on the AC side by a friend of mine. 26.6 mile round trip.

 

[Lee Sang Koo]

The problem is the DJI logic board, frankly. Once you understand how it works you realize how many hoops we have to jump through to double flight time.

For those of you thinking it's impossible to get beyond 30-35min, there is hope

Here's a 49:13 actual flight (vs hover) with an M100 with only a battery mod on the AC side by a friend of mine. 26.6 mile round trip.

Damon, what is mean " AC side" ??

 

[Phatzo]

Damon, what is mean " AC side" ??

AC- Air craft / Drone


Sent from my iPhone using Tapatalk

 

[Lee Sang Koo]

The problem is the DJI logic board, frankly. Once you understand how it works you realize how many hoops we have to jump through to double flight time.

For those of you thinking it's impossible to get beyond 30-35min, there is hope

Here's a 49:13 actual flight (vs hover) with an M100 with only a battery mod on the AC side by a friend of mine. 26.6 mile round trip.

Damon, What type of battery used ?

 

[Lee Sang Koo]

AC- Air craft / Drone


Sent from my iPhone using Tapatalk

Thank you^^

 

[damoncooper]

Damon, What type of battery used ?

He used a MS 8000 on an M100

 

[Ruckusman]

personally I wouldn't mix standard Lipo and LiHV, there is a voltage difference between a fully charged LiHV inspire battery and a standard LiPO, that will equate to a current flow that slightly overcharges the standard LiPO, the risk of issues is small, however it is a risk nonetheless.

I'm with Damoncooper, the intelligent flight batteries are a PITA, plus any power system that can, and has been known to power off in flight, to save the battery at the expense of the entire craft is quite frankly an absurd liability, but they're a **** good income stream for DJI, a huge income generator

 

[Nick H.]

I think it is three-fold for DJI. I agree with the massive income generator because it forces the customer to go to them for batteries. Secondly, they can sell even more if their aircraft do not require hobby grade chargers in order to operate. Lastly, it saves them from having to deal with the inevitable constant questions and burned down houses from non-intelligent people who can't seem to grasp what is necessary for charging lithium batteries. I'm just glad we have a work-around.

I think the LiHV batteries are worth it. There is a significant weight difference to Lipo batteries when comparing the same capacity. The LiHV is always lighter. Secondly, LiHV holds up the voltage. This prevents the Inspire from lowering the propeller thrust output on heavy current draws and when getting closer to the end of the battery.

 

[Lee Sang Koo]

He used a MS 8000 on an M100

I think that metrix is possible but inspire is not. I just know that Inspire is designed heavily.
Metrix is 500g ~ 600g lighter than inspire. so, it has very good efficiency as 5000mah~6000mah.
Your information could be very valuable for me^^

 

[Raphael Dahan]

I think that metrix is possible but inspire is not. I just know that Inspire is designed heavily.
Metrix is 500g ~ 600g lighter than inspire. so, it has very good efficiency as 5000mah~6000mah.
Your information could be very valuable for me^^

I think we can make the inspire lighter, by eliminating the heavy transforming landing gear system and the VPS ~ 750 gr??

 

[Lee Sang Koo]

I think we can make the inspire lighter, by eliminating the heavy transforming landing gear system and the VPS ~ 750 gr??

Yes! I don't feel need the heavy transforming landing gear system and the VPS... Did you see lighter inspire?

 

[Raphael Dahan]

mine is 1.8.1 iirc, with turnigy 2 x 6s 2650mah 20c and TB48 with around 85% battery life(old battery with 50+ cycles) it hovered around 22 minutes,and light flying gave me 19 minutes to 30%.But i lost the green bar flight range calculation too,but there are flight minutes displayed on the dji go app (it says 25 minutes from the take off moment).The batteries are mounted this way,no flight behaviour differences,motor sounds ok. Oh,dji inspire V1 + x3.

edit : the green bar flight calculation is there,didnt notice it. but does it give me correct calculation as now i have more battery capacity?

Yesterday I flew my i1 v2 with x3 cam, 2x2700 fixed on the landing tube (like you did).
Stability - rock , flight time- 29.2 m at 30% left in main and 29% in aux. quite happy with the results.
Waiting for the 8000 results.

 

[Lee Sang Koo]

Yesterday I flew my i1 v2 with x3 cam, 2x2700 fixed on the landing tube (like you did).
Stability - rock , flight time- 29.2 m at 30% left in main and 29% in aux. quite happy with the results.
Waiting for the 8000 results.

what kind of battery ?? your 2 x 2700mah