Battery Mod Info

[Pescatoral Pursuit]

Word of warning if you are mounting your batteries to the T-fitting for the motor arms:

I tried out my new 5200 multi stars that are longer and flatter than a standard brick shaped battery. Hover and gear up and man that battery looks close to the prop.

A couple seconds of hovering at eye level in a 15-25 mph wind and I hear a brief "brrrrrrt." Not cool. Gear down and i notice for the first time that the motor arm pivots in the tee fitting which i assumed was fixed. NOT. Raising the landing gear actually rotates the battery closer to the props and depending on placement and shape, can cause interference as happened ever so slightly and briefly on my drone.

Fortunately no harm whatsoever occurred to battery or prop but served as a warning to thoroughly examine all the variables when "accessorizing" the aircraft.

In gear down, props come within 3/4" of the top of "lift tube" and within 3/4" of the aux batteries in gear up with the batteries low enough that they rest against the strut bracket with gear down.

 

[damoncooper]

Update on the MS 6600 LiHV and 8000:

Flew them both for the first time today, near full throttle in GPS out about 6 miles and the 6600 had a slight advantage over the 8000. Actual hard throttle forward flight time was about 21-23 min each.

 

[damoncooper]

Titan batteries should arrive (finally) tomorrow. They had lost my order. I'll update once I've given them a spin.

 

[Pescatoral Pursuit]

Titan batteries should arrive (finally) tomorrow. They had lost my order. I'll update once I've given them a spin.

Gravitating more towards high C batteries?

 

[Granger]

Hi Guys, Just wanted to post a pic of where I attached the Aux power wires. Seems to be working well.

 

[damoncooper]

Gravitating more towards high C batteries?

Opposite: these are 5C

 

[Pescatoral Pursuit]

Opposite: these are 5C

Fast discharge?

View attachment 9500
Hi Guys, Just wanted to post a pic of where I attached the Aux power wires. Seems to be working well.

Looks great. You really made it easy on yourself taking the extra step to disconnect the motor wires.

 

[emtea]

Update on the MS 6600 LiHV and 8000:

Flew them both for the first time today, near full throttle in GPS out about 6 miles and the 6600 had a slight advantage over the 8000. Actual hard throttle forward flight time was about 21-23 min each.

Are you getting the same time on the 6600 than the 8000? Interesting....

 

[Heipro]

I'm making it^^
View attachment 9397

Cool, can u tell me what battery you use plz ?

 

[calde315]

Interesting thought. I would think that because the batteries are mounted on the motor side of the hinges, any additional weight is not affecting the lg motor, gear, hinges, etc. However the same cannot be said about batteries mounted on/ under the body as the drone in flight / hover is "hung" by the motors and to lower the landing gear is to hoist the body up, including the additional weight of the body mounted battery(s). I wouldn't know if the mechanical advantage of the landing gear is sufficient to compensate for the added weight without over-stressing itself. It may very well be.

Just following this for a couple days but I'd have to agree with the other member. My concern with mounting there is you have a longer lever arm and therefore increased torque that the landing gear motor needs to produce. By adding weight to anywhere on the arms I think it'll stress that motor more than normal but If you wanted to put on the arms I think the closer to the pivot (landing gear motor) the better.

 

[damoncooper]

Are you getting the same time on the 6600 than the 8000? Interesting....

I'll know have a better assessment after a few changes and some additional testing

 

[gazza95]

calde315. By mounting batteries outboard near the motors you actually reduce stress on landing gear motor. In flight weight is under motors and LG motors only supporting body weight and when on ground extra battery weight is supported by the legs.

The downside is you massively change roll moment of inertia and hence "PIDs" are out. As there is no proper way of adjusting on an Inspire you have to adjust roll sensitivity to compensate.

 

[Nick H.]

the inspire charger, can you walk me through your steps?

Sorry I didn't get to your question earlier, Granger. Yes, I can go through the steps of making this charger. First thing is getting a very powerful power supply. 6S batteries require a lot of power to charge them. I tried getting by with a 450W and then a 600W, but it really wasn't getting the job done the way I wanted it - especially once I shifted to using auxiliary batteries as well. I've been using the Turnigy 1080W power supply for awhile now and it has been rock solid. Plenty of power to go around and very stable voltage regardless of the load you put on it. It is also inexpensive for what you are getting.
Turnigy 1080W 100~120V Power Supply (13.8V~18V - 60amp) (US Warehouse)

I then bought an electrical box to contain all of the electronics.
https://www.amazon.com/gp/product/B005T94MQU/ref=oh_aui_detailpage_o01_s02?ie=UTF8&psc=1

The DJI batteries have all the charging circuitry built in. They just need a constant supplied voltage of 26.0-26.1 volts. I use DC-DC converters to do this since the power supply cannot put out that much voltage.

Amazon.com: DROK® 600W 12A DC Boost Voltage Converter 12-60V to 12-80V Step-up Power Supply Transformer Module Regulator Controller Constant Volt/Amp Car Regulated Laptop Battery Charger LED Driver Generator: Electronics

I bought one of these for each charging bay. The conversion isn't perfect, hence the reason for the large heatsink. They get hot. I don't know the efficiency of these converters so I wasn't comfortable having two batteries hooked up to one converter. It made more sense to do one converter per battery.

The converters have potentiometers to set the voltage and amp output, but they don't have their own readouts for volts and amps, so I picked up some digital gauges.
Amazon.com: DROK®0.28'' DC4.5-30V 50A Voltage&Current Digital Multimeter Tester 12V/24V Volt Amp Gauge Panel Monitor Integrate Voltmeter&Ammeter with Red/Blue Dual Color Display Equipped with Current Shunt: Automotive

Best to have a multimeter to check the gauges for accuracy. The gauges do have adjustment screws on the back so you can adjust them to match what your multimeter says. This is important as the DJI batteries are finicky about the voltage used to charge them. I didn't worry about the accuracy of the amp gauge as they come close enough out of the box. I set the DC-DC converter to charge the batteries between 6-7amps. Pretty much the speed the 180W DJI charger will charge them. One very cool thing you get to see with the gauges is how the charging circuitry on the DJI batteries work. The voltage drops to the voltage of the discharged battery when you first plug them into the charger. Once the battery reaches 26 volts, you slowly see the amps drop down to zero.

I made 3 bays but have room for 4. So far, I really haven't needed another so I'm cool with what I have set up for now.

I wanted to carry the box easily so I picked up a handle.
https://www.amazon.com/gp/product/B00JQYVJVK/ref=od_aui_detailpages02?ie=UTF8&psc=1

The power supply gets hot, so I installed some fans on the outside to cool it off.
https://www.amazon.com/gp/product/B003WM184A/ref=od_aui_detailpages02?ie=UTF8&psc=1

I also disassembled the power supply to make the wires to the on/off switch longer because I wanted to mount it on the outside of the box. I used one of those cheap parallel charging boards to get the charging plugs for each of the batteries. I cut it up and soldered my wires on the backside of it then glued them to the inside of my box. I cut out a slot for each battery such that the battery would plug into the plugs I cut from the parallel board.

The Turnigy 1080W has a lot of power to spare, so I set up some charging jacks on the outside of the box so I could plug in my Turnigy 1344W charger to charge up the 6600 Multistars. I can charge both of my 6600 LiHV Multistars at 20amps along with 3 DJI batteries at the same time - All from one power supply.

Here are some pictures of the setup. Feel free to ask any other questions.



[url=https://flic.kr/p/KN6Joc]


WiFi module with the Turnigy 1344W charger. Use the Hyperion app to control charger wirelessly.
[url=https://flic.kr/p/KFfvwv]

I used 12 gauge wire coming out of the power supply so the wires wouldn't melt due to all the current.
[url=https://flic.kr/p/KN6Hjt]

[url=https://flic.kr/p/KmXK8j]

[url=https://flic.kr/p/KCN7ms][/url][/url][/url][/url][/url]

 

[Nick H.]

Titan batteries should arrive (finally) tomorrow. They had lost my order. I'll update once I've given them a spin.

Very cool, Damon! I went to check these out once I saw your post. I can't believe the weight difference! 7000mah at 612g. Sure, it isn't LiHV, but I would imagine the lighter weight would give great results.

 

[IrishSights]

calde315. By mounting batteries outboard near the motors you actually reduce stress on landing gear motor. In flight weight is under motors and LG motors only supporting body weight and when on ground extra battery weight is supported by the legs.

The downside is you massively change roll moment of inertia and hence "PIDs" are out. As there is no proper way of adjusting on an Inspire you have to adjust roll sensitivity to compensate.

Sorry, I don't see the physical validity of what you are saying. The lifting motor mechanism was designed to lift the weight of the arms it was not designed to lift an extra 600 odd grams. So absolutely no way can it reduce the stress on the landing gear mechanism. It's not just the motor stress. Not saying it won't do it of course!

PFAW Holder
BNUC-S Qualified

 

[JJ_2016]

For me it makes sense. The landing gear is lifting the "body" and not the arms when its airborne.

 

[damoncooper]

Just arrived. I'll report back when I have a chance to test them next weekend.

There's a small chance they will cause a fire actually, due to their ultra low C. But batteries share the aircraft voltage load when teamed up, so at least on paper, they should be fine. The manufacturer told me directly though that they've never tried them on an Inspire. Oh boy.

 

[Nick H.]

Wow!!! 7000mah at 460g! That is considerably less than the 6600 Multistar LiHV. 300g less, in fact. That is very significant in weight savings. Considering the smaller change in weight between the 3500 and 2600, my bet is a longer run time with the dual 3500s.

 

[JJ_2016]

3 of those 3500's at 690g and adjusting the low voltage cutoff to 2.5V would be interesting to try.

 

[Nick H.]

JJ, I didn't even think yet to do 3 of them, and that still comes in under the Multistar 6600. More capacity, less load on each cell as well for that lower C rating. 10,500mah at 690g. Wow. Almost sounds too good to be true. I figure you could have one on each arm and another below the main battery. I have a feeling that a positive review from Damon may cause Titan to get a few orders. I'm surprised that the reported weight of the 3500s is so much more than Damon's measured weight. Titan says they are supposed to be 311g.

I'm also surprised that the rated charge rate for the 3500 is less than 1/2C. I don't understand why they wouldn't be 1C.