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This is a really incredible project. Maybe it will stimulate someone to mass produce them or contact you to partner with them. I know that there are a lot of us out here who would gladly pay a decent price for a device like this. Given that a set of batteries costs $320, I see no reason that we would not pay $500 or more for a unit. And as you know, there's a pretty high markup on a lot of electronic components in the retail space. A company that is capable of accessing wholesale prices on components could bring many of the costs you endured down significantly I'd guess.

I see a lot of potential in this product and as an Industrial Designer, I always cringe when I see something like this posted on the web not knowing if the intellectual property aspects of it are protected. You might think of Patent Pending your concept at a minimum and even better, pay a Patent Attorney to help you file some documents to protect it. Surely there are some aspects of it that would merit a patent.

One thing that I noticed was that the battery contact leads that plug in vertically are vulnerable to damage if the lid was to get closed on them while they are plugged in. Even with the lid lying fully back against the ground, a stiff wind might be able to lift it and slam it shut. I might suggest that you incorporate some kind of lid restraint so that it can't be closed unless you want it to. That will protect your somewhat fragile leads that are plugged in.

An amazing piece of engineering. I hope you can find a way to mass produce it and make some good money while making a lot of us happy. I for one would buy one from you tomorrow if you had them available.
Thank you! I enjoyed reading your reply and wanted to make some comments on it.
It was one heck of an undertaking to complete on my own in my spare time -- especially since my discipline in Mechanical and Electrical engineering is all self-taught; I'm a software engineer! I worry that if this were ever to be mass produced the quality would go down and the "NO COMPROMISES" mantra I had while creating this would be thrown out the window. That is why I made this for myself and possibly will sell the one extra I've provisioned for -- if I can find the right buyer. That being said, for the one-off version I'd build the $500 you mentioned wouldn't even cover the cost of the power supply module and Pelican case -- so unfortunately that number is *WAY* off.

As for the patent aspect, I've gone down that route before both as an employee working for a company and an individual and believe me there is no point in spending the money it takes to get a patent for this, and then even MORE money defending that patent should someone breech it.

The case weighs 42 lbs fully loaded, and the top of that Pelican case is going no where with wind, knocking into it, or any other accidental gesture to close it. While the XT60 wires do stick up when in-use, it really does not post an issue with the lid coming down on them. The AC Line cord / DC input cable will also provide resistance for the lid preventing it from coming down too hard on those connectors (and the only way it comes down is if someone forces it down on-purpose). Nevertheless, your idea is a good one and I welcome more feedback like that -- especially from someone who is a real industrial designer!

How much would you charge to build another one???
The hardest part (and one that I had very little outside control over) was getting the G10 material and aluminum anchors machined. Since this was such an undertaking to have done I had TWO sets made -- initially as backup and then later on in case I decided to sell the extra set in a completed second unit. I still have to add up my total bill of materials, but again I purchased the parts at retail without the plan to source OEM components for mass production. For me to buy all the parts again, take the time to custom assemble another one, etc it would be pretty costly. I need to find the right buyer (A professional who gets paid for professional work; and pays for professional work in return) in order to build out the second unit.


Does this setup do a better job of balancing cells than the DJI Hub?
As Mad_angler1 had posted, that is exactly correct -- the balancing is all done in the battery itself. The charge hub simply looks at the voltage of whatever batteries are connected and distributes power to the two highest voltage packs (the 2 closest to being fully charged). There is no intelligence in the power supply, charge hub, etc. It is all done in the batteries.
Charges 3 batteries and controller at the same time with an output of 26.3 volts at 2.5 amps I bought two for $40 each and they work spectacularly at charging my batteries simultaneously


So you say. I'm suspicious of the accuracy of that circuitry. I've had two batteries with "broken cells" (variance of .1 or greater) that have only had 10 or so cycles. Either the batteries are poop, I got two that were made on Friday afternoons, or the quality of the balancing is not up to snuff....imho
I too have experienced this. DJI is pretty stingy with the rules they enforce when it comes to their batteries and what they consider "safe" and "flyable" -- but as a manufacturer mass producing aircraft like this they have to be. I've had the same problem with 2 of my older batteries (always charged on OEM charge hubs and power supplies). It's just their algorithms and tech inside the battery that causes this, it's unrelated to the charge hub or power source.
Charges 3 batteries and controller at the same time with an output of 26.3 volts at 2.5 amps I bought two for $40 each and they work spectacularly at charging my batteries simultaneously
That thing is a joke compared to what I have built. If it works for you, that is great -- but where that does 2.5 amps (per battery? total??) mine does up to 10 amps per battery, 60 amps total output. Mine also has the ability to run from many different power sources and can charge batteries very quickly in the field -- that was the purpose of my creating it.
 
Amazing work. I'd buy one for sure of you decide to sell them.
I still have to add up my cost and make a full Bill of Materials, but since this was made for my own uses, with zero compromises, using off-the-shelf parts purchases at retail -- it isn't cheap.. not for the components, not for the custom machine shop work, and not for the time and effort it takes me to build them in a one-off fashion.

Unfortunately the cost would make it only viable to a Hollywood professional type of high-end-user; One that NEEDS batteries charged FAST while in the field (from a variety of different power sources) and can immediately justify the high one-time cost of this product because of the immediate benefits it yields.
 
So you say. I'm suspicious of the accuracy of that circuitry. I've had two batteries with "broken cells" (variance of .1 or greater) that have only had 10 or so cycles. Either the batteries are poop, I got two that were made on Friday afternoons, or the quality of the balancing is not up to snuff....imho

This is more firmware than the capability of the balance circuit, DJI have set unbalance limits in fw and anything beyond that it locks out, this has been the case with the Inspire 1 packs too and people have successfully re balanced the packs manually and they have been fine.

You have to take into account DJI approach is safety and usability, these packs are designed to be used by people who simple have no idea about Lipo usage and safety, DJI have mostly very successfully removed the risk associated with Lipo usage, while random bad failures will always happen it's extremely rare to hear of a DJI smart battery going up, unfortunately this 'nannying' comes at a cost of some of the issues we have seen in the passed such as LVC, self discharge and poor balancing.

Overall these packs are very reliable if stored at 50% and checked for capacity every 30 days when not in use and these days most of the quirks have been ironed out now.
 
Respect, bro ... that's all I can say! Been there, did that, although on much smaller scale, suitable for my Inspire 1/Phantom needs so far. Your "no compromise" approach is the way to go for at least one reason. Satisfaction that is. It's hard to describe feel when tedious concept development, CAD design, research, parts sourcing, manufacturing and assembly, mistakes and failures are over, and your idea finally works like a charm. Money are no object, labor unaccountable, it's your's and only your's! Why bother? Because you can, and others can't! The fell I'll compare to a mountain climbing only. All this effort, oxygen deprivation, suffering is irrelevant when you finally reach the summit and take a look around :D ...

As for my project, I'm lucky enough to have a plenty of power on my boat, equipped with huge 24VDC battery system constantly topped by 1KW solar array. This floating power plant was developed to supply energy for electric propulsion and various appliances during weeks long expeditions into wilderness. On deck Honda generator is optional only when weather will not co-operate, and - honestly - never used by far. However, the issue of charging drone batteries in field came later. To achieve this, I've build a discrete multi-channel chargers employing step-up or step-down DC converters with adjustable output voltage and current. Inspire 1 TB48 batteries may refuse charging current bigger than 8A, therefore I'm trying not to abuse'm too much with conservative 7A. Works charmingly for me, allowing to charge a set of 4 batts in average 60 minutes. Here's my double-channel charger for Phantom batteries, draining 15A current from 12V battery. Top LED meters shows charging currents at this moment ...

IMG_0155.jpg

Similar configuration for TB48 batteries and 24V input, here shown at "brainstorming" stage of development.

IMG_0152.JPG

Alternatively I'm using 12V/40A DC power supply when 120VAC is available ...

power supply.jpg

Again, I'm taking my hat off for your bravery, determination and successful execution ...

BTW, If you have few more minutes to waste, you may see this video:


You'll get better picture of what I'm talking about ...

Cheers,
Matthew.
 
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David this is very impressive!

I must ask or if you prefer to message me I do have a question in regards to getting power to the batteries.

I am about finished up with a wind farm inspection and ran into the issue of not having enough chargers and burning out two of the cheap blue fast chargers in two days.

I went on a last limb and purchased a venom x4 channel @ 100watts per to try to rig up my own charger with the leads of these cheapo blue fast chargers. All is soldered correctly but the venom shows a reading of 0v and will always prompt with a connection break upon trying to charge. Can you provide any insight to let the charger see the voltages? Is the only real way to send power through and then watch resistance climb? Not sure exactly where to go from here or if it is possible.
 
David this is very impressive!

I must ask or if you prefer to message me I do have a question in regards to getting power to the batteries.

I am about finished up with a wind farm inspection and ran into the issue of not having enough chargers and burning out two of the cheap blue fast chargers in two days.

I went on a last limb and purchased a venom x4 channel @ 100watts per to try to rig up my own charger with the leads of these cheapo blue fast chargers. All is soldered correctly but the venom shows a reading of 0v and will always prompt with a connection break upon trying to charge. Can you provide any insight to let the charger see the voltages? Is the only real way to send power through and then watch resistance climb? Not sure exactly where to go from here or if it is possible.

You can’t use a Lipo charger to charge these packs, you need a current limited 26.1v PSU, the reason your getting the error is the charger is looking for voltage from the pack first before it enables the charge cycle.

The batteries have the charge circuit built in you just need to provide it the correct voltage with a limited current, a Lipo charger is going to try and actually use it’s charge cycle so start with constant current then shift to constant voltage, this can completely confuse the packs internal charge circuit and give problems.

These packs will simply begin to charge them selves when you provide 26.1V, I’d recommended current switch mode pay limited to no more than 6A.

These can be purchased fairly cheaply.
 
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You can’t use a Lipo charger to charge these packs, you need a current limited 26.1v PSU, the reason your getting the error is the charger is looking for voltage from the pack first before it enables the charge cycle.

The batteries have the charge circuit built in you just need to provide it the correct voltage with a limited current, a Lipo charger is going to try and actually use it’s charge cycle so start with constant current then shift to constant voltage, this can completely confuse the packs internal charge circuit and give problems.

These packs will simply begin to charge them selves when you provide 26.1V, I’d recommended current switch mode pay limited to no more than 6A.

These can be purchased fairly cheaply.
Yes, this is the issue. Inspire batteries will refuse charging current bigger than around 8A, while some LiPo chargers may deliver 20 or more. Therefore only chargers with adjustable current limiting circuitry can be employed (i.e. [POWERNEX] MEAN WELL NEW HLG-150H-24A 150W 24V 6.3A LED Driver Power Supply | eBay).
 
Yes, this is the issue. Inspire batteries will refuse charging current bigger than around 8A, while some LiPo chargers may deliver 20 or more. Therefore only chargers with adjustable current limiting circuitry can be employed (i.e. [POWERNEX] MEAN WELL NEW HLG-150H-24A 150W 24V 6.3A LED Driver Power Supply | eBay).

Inspire 2 TB50’s will Charger at 26.1 volts and UP TO (but not more than) 10 amps. They stop charging at anything above 10 amps and blink an error code indicating “over current”.
 
Inspire 2 TB50’s will Charger at 26.1 volts and UP TO (but not more than) 10 amps. They stop charging at anything above 10 amps and blink an error code indicating “over current”.
Possibly yes, my knowledge is limited to Inspire 1 batteries behavioral properties (TB47 and 48). Apparently TB50 intelligent battery is more tolerant to charging current abuse.
 
Possibly yes, my knowledge is limited to Inspire 1 batteries behavioral properties (TB47 and 48). Apparently TB50 intelligent battery is more tolerant to charging current abuse.

I was able to charge TB47/TB48 batteries at 10+ amps without issue. I think they put the current regulator into the TB50's but it wasn't in the TB47/TB48's... Or maybe it was just set higher in the older batteries -- but the older batteries took much more current than the newer TB50's in my experience.
 
I was able to charge TB47/TB48 batteries at 10+ amps without issue. I think they put the current regulator into the TB50's but it wasn't in the TB47/TB48's... Or maybe it was just set higher in the older batteries -- but the older batteries took much more current than the newer TB50's in my experience.
Hmm, your statement is somehow conflicting with my experience ... All 4 of my TB48 batteries shuts down when receiving 9-10A charging current. I'm perfectly fine with somewhere around 7A, which render about 60 minutes of TB48 battery charging time, when depleted down to 15%. Perhaps you may crank it up a bit more, but I've found that the gain - in terms of charging time - is negligible, IMHO.

All DJI's intelligent batteries are equipped with voltage and current sensor (not regulator), and set to shut down on input bigger than whatever they decide to determine by FW. Some people believe that this threshold is way too conservative, but it is what it is. It will prolong your battery life span on long run, no doubt.

How the TB50 batteries will behave with my chargers? I'm about to find out, considering the purchase of mighty M200 aircraft :) ...
 
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Respect, bro ... that's all I can say! Been there, did that, although on much smaller scale, suitable for my Inspire 1/Phantom needs so far. Your "no compromise" approach is the way to go for at least one reason. Satisfaction that is. It's hard to describe feel when tedious concept development, CAD design, research, parts sourcing, manufacturing and assembly, mistakes and failures are over, and your idea finally works like a charm. Money are no object, labor unaccountable, it's your's and only your's! Why bother? Because you can, and others can't! The fell I'll compare to a mountain climbing only. All this effort, oxygen deprivation, suffering is irrelevant when you finally reach the summit and take a look around :D ...

As for my project, I'm lucky enough to have a plenty of power on my boat, equipped with huge 24VDC battery system constantly topped by 1KW solar array. This floating power plant was developed to supply energy for electric propulsion and various appliances during weeks long expeditions into wilderness. On deck Honda generator is optional only when weather will not co-operate, and - honestly - never used by far. However, the issue of charging drone batteries in field came later. To achieve this, I've build a discrete multi-channel chargers employing step-up or step-down DC converters with adjustable output voltage and current. Inspire 1 TB48 batteries may refuse charging current bigger than 8A, therefore I'm trying not to abuse'm too much with conservative 7A. Works charmingly for me, allowing to charge a set of 4 batts in average 60 minutes. Here's my double-channel charger for Phantom batteries, draining 15A current from 12V battery. Top LED meters shows charging currents at this moment ...

View attachment 16330

Similar configuration for TB48 batteries and 24V input, here shown at "brainstorming" stage of development.

View attachment 16331

Alternatively I'm using 12V/40A DC power supply when 120VAC is available ...

View attachment 16332

Again, I'm taking my hat off for your bravery, determination and successful execution ...

BTW, If you have few more minutes to waste, you may see this video:

.

You'll get better picture of what I'm talking about ...

Cheers,
Matthew.

Not sure about all this battery stuff, but your video and boat and location are Awesome! Where were you? Did you build the boat yourself? Maybe a separate thread just on your wilderness setup. Do you have a YouTube channel with more of this? Please share!
 
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Not sure about all this battery stuff, but your video and boat and location are Awesome! Where were you? Did you build the boat yourself? Maybe a separate thread just on your wilderness setup. Do you have a YouTube channel with more of this? Please share!
Thank you ... Yes, I designed and build the boat from scratch. I tow her every summer from Edmonton AB across Rockies to central-south parts of BC. I travel around, I camp on ground or on water, I live on. I film and photograph landscapes to watch during long Canadian winters. It's like a pornography for nature freaks. This video features mostly the scenery of Christina, Slocan and North Barriere Lakes. Perhaps one day I'll do more elaborate video documentary about my boat/drones setup and publish on YT. I'm a shy guy ...
 
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I have come up with the ultimate solution that has zero compromises and offers the best results across the board...

Aces,

Am I correct in assuming that you're using an AC power supply, with a separate buck/boost DC-DC converter for DC sources? I've been looking for a single power supply unit that would take an AC or DC input, but have only found ones that will work on high voltage DC. An all in one with a buck/boost on the input stage that could handle 12 - 24v DC or 120 - 240 AC would be ideal, but doesn't seem to exist.

Would you provide a link to the power supply you used?

Thanks,
Zac
 
Aces,

Am I correct in assuming that you're using an AC power supply, with a separate buck/boost DC-DC converter for DC sources? I've been looking for a single power supply unit that would take an AC or DC input, but have only found ones that will work on high voltage DC. An all in one with a buck/boost on the input stage that could handle 12 - 24v DC or 120 - 240 AC would be ideal, but doesn't seem to exist.

Would you provide a link to the power supply you used?

Thanks,
Zac

Zac -- thanks for the comments! So yes, I can accept from 90-264v AC (wall outlet, generator, etc) or 10-25v DC (car/truck/boat battery, etc). Remember the output is 26.1 volts to charge the Inspire batteries, and I can only accept up to 25v; that is because I ONLY have boost converters, no buck converters. If the charger is delivered more than 25V DC (from the AC transformer or the DC input binding posts) it detects the over-voltage and shuts itself down to prevent damage to itself or the batteries. It has over/under voltage and over/under current protection for situations like this.
 
Zac -- thanks for the comments! So yes, I can accept from 90-264v AC (wall outlet, generator, etc) or 10-25v DC (car/truck/boat battery, etc). Remember the output is 26.1 volts to charge the Inspire batteries, and I can only accept up to 25v; that is because I ONLY have boost converters, no buck converters. If the charger is delivered more than 25V DC (from the AC transformer or the DC input binding posts) it detects the over-voltage and shuts itself down to prevent damage to itself or the batteries. It has over/under voltage and over/under current protection for situations like this.

So is it correct then that your power supply and boost converter are separate units, not a single PS with a built-in boost and rectifier? Would you mind sharing the power supply you used?

Thanks!

Edit: After re-reading that last reply, it looks like you are probably using an AC transformer that outputs 24V, serial into a boost converter, with a separate tap for a DC input downstream of the transformer. In that case you'd be using the boost converter regardless of the input source, rather than having an AC power supply with 26.1V DC output in parallel/switched with a DC boost. That would make more sense. Is that a correct assumption of your architecture?
 
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So is it correct then that your power supply and boost converter are separate units, not a single PS with a built-in boost and rectifier? Would you mind sharing the power supply you used?

Thanks!

Edit: After re-reading that last reply, it looks like you are probably using an AC transformer that outputs 24V, serial into a boost converter, with a separate tap for a DC input downstream of the transformer. In that case you'd be using the boost converter regardless of the input source, rather than having an AC power supply with 26.1V DC output in parallel/switched with a DC boost. That would make more sense. Is that a correct assumption of your architecture?

Zac - Bingo, you nailed it :)
 
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