New battery cells

As many of you know, I have been developing a new electric paramotor. For various reasons we have kept the cells that we are using a secret. Up until this point those Samsung 50s 21700 cells (not 50E cells) have been used only in the highest end drill batteries such as the DeWalt flexvolt batteries and they have been rewrapped and sold as the vapcell T50. This alone up until this point has basically used the entire supply of these cells made by Samsung. Also evey company using these cells has stayed extremely quiet about it. For this reason, they have been in production since about 2018 and yet nobody knows about them. Anyway, one of our community members recently posted this on Facebook

Funny thing is that the same person a month or two ago was making fun of me for claiming such cell existed.:sweat_smile:

I realize now that our development has been slow enough such that you all would find out about this cell before we hit production, so I might as well help out the E-ppg community to help develop faster.

Samsung 50s vs Molicel P42A @ 15 amps

those who know their way would write that the samsung 50 S is suitable in very high numbers for trike or for ultra-light thermal concepts up to a maximum of 9 kilowatts of starting power.

the samsung 50 S is unsuitable for eppg standard with a typical 3-4 kilowatt battery size because it is constantly hot and only has 70% capacity after only 20 cycles … :wink:

my posting in facebokk refers to pure thermal concepts with 9 kilowatts of starting power and are mainly used with a maximum of 6 kilowatts in the climb or with 3 kilowatts in the level.
the concept is the apco kitto with a folding propeller without a cage and a 15 S / 10 P battery.

total weight 18.7 kilograms including rescue parachute. with the trike s i see a minimum of 15 S 40 P so that the cells in the housing do not overheat. the samsung 50 s is not a miracle cell for the standard.

you can only use it if the concept is coordinated for it. otherwise it is currently better to stay with the well-known 21700 with around 4000 mah.

It is comparable to the sony VTC 5 and VTC 6:

when the vtc 6 was used for the first time in the same number of units as the vtc 5, there were temperature problems because the total amount of heat that is given off was around 20% more when the sony vtc 6 came the battery at its temp limit by longer running time. only when the internal resistance, and thus the efficiency of the cells, is better, more capacity can also be implemented directly.

At the moment, the withdrawal often has to be reduced or the number of cells increased in the case of cells with more capacity and the same weight and size.

It is important to mention that the samsung 50 s cannot be bought by hobby people. therefore i think it will take another 1-2 years until the molicell and sony / murata in the 5ooo class is available for special eppg applications.

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Very true. We will be running closer to 5kwh battery size to try go easier on the cells. We also working out new methods of cooling the cells as a more standard battery pack design like the sp140 would have the cells overheating. If proper cooling can not be achieved, we will likely use the molicel P42A. Of course we are still in the testing and development stage, nothing is set in stone.

This was true up until about 1 month ago, there are now people selling these to the general public. In the worst case scenario we will go though the paperwork route of getting our battery packs approved by Samsung.

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Ya availability is really the biggest factor along with price. Doesn’t make sense unless everyone wants to pay like $2000 or more per pack. Also haven’t see much testing on cycle life but ya if its a low as Thomas says then not worth it.

And again as always once your pack is ready and its good quality then I’m happy to buy it from you.

Also I’m pretty sure mooch has heard about them just availability is bad so it hard to even get one cell for testing. Samsung 50S (a 40T with 5000mah!) - Battery Builds - forums you can see him talking about it 4 months ago.

The selling price of our complete pack would probably come out to the ball park of $2000. Definitely not as good price wise, but it could be worth it to have that additional 20+ percent energy density. Also for this pack we are trying to develop new cooling methods. This way we could throw in traditional high current cells like the molicel P42A or Samsung T40. This way people accustom using regular paramotors can really push their electric units without overheating the batteries. It would also allow a lower cost option to those who don’t care for the extra ~13 minutes of flight.

I haven’t seen much testing on that either. The 50s cell is the next generation of the Samsung 48x cell which is rated at an insane 3,000 cycles before hitting 70% capacity(this is w/ discharging to 3.0v charging to 4.15v). The 50s is also used mostly in applications such as power-tools, electric lawnmowers, and E-vehicles that have traditionally used batteries with a good cycle life. So we have hopes that under typical E-ppg conditions it will have a decent cycle life, but once again we are not yet sure.

As mentioned before up until very recently the availability has been almost non-existent and even now it’s not great. We have been talking with a few suppliers and believe we can get a solid supply of these 50s cells.

As you have mentioned many times, much of what we are working on is unproven and is risky. On the other hand, if it has the possibility of pushing the development of E-ppg it is worth it.

my personal conviction: if you have to actively cool cells, it is a sign that the cells are not suitable for this setup. the heat dissolves inside the cells and damages them in the long term. even if one removes the temperature outside, it does not change the fact that the efficiency is poor due to too high internal resistance. therefore a lot of power required = many cells, then ok … small controlled power also possible with fewer cells. standard application = better to use high-current cells.

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I agree with this, I’ll attempt to show you my train of thought.

So I understand from this that you believe that 150 of these cells in a 15s10p configuration is capable of 9kW starting power, 6kW climb, and 3kW level. We will be using a bigger battery with 264 of these cells in a 24s11p configuration. To me this means that without cooling we can pull about 16kW starting, 10.5kW climb, and over 5kW level. I feel like this is good enough performance that we could fly entirely without cooling. For me the cooling is more for idiot proofing and prolonging battery life rather than allowing us to push the battery to the limit.

Once again the plan is to provide a second battery option with high current cells for people who will push their battery harder.

Ohh i thought you where going to use a bigger battery pack? That is the exact same configuration OpenPPG uses, might as well make the case the same size so its cross compatible.

There is a chance we will go to a 24s10p for a 4.4kWh battery pack if we determine the cells can handle the current. Otherwise we will stick with a 24s11p for a 4.85kWh battery pack. Even the 24s11p battery is pushing the weight that we want, but any smaller and we could possibly be pushing the cells too hard.

I have recently been thinking a lot about an air cooling system for the battery such that air would flow through the inside of the battery being pulled through by the propeller. The battery could then have some form of sealer coated on everything inside to keep any moisture from getting anywhere in the battery where it should not be. Additionally cells closer to the incoming cool air would have a thicker coating to allow for a better balance in battery temperature. My plan was to then build two air ducts onto each side of the battery mounts one facing forward a the other facing backwards to pull that air through the battery. I hope I described that in a way that makes sense. Long story short, I think our battery would fit just fine in the sp140, but it might need these air ducts added on your unit to cool the pack.

Additionally, if we are going for compatibility, do you care if we just use the same Qs8 connectors that you are using?

The connectors can really come last but are you planning to do any smart BMS connection with the controller? Because then different connectors might be better.

I would really like a way to display live battery temperatures through a wired connection to the BMS. For now we have just been playing around with using the Bluetooth system in the BMS to display information as we can see things such as the live power output, the amount of power used, battery percentage remaining, temperature, etc. On the other hand I don’t see it viable for production as it doesn’t show ESC temperature, allow us to adjust any parameters outside of the battery using the display, and it requires us to use a phone.

arithmetically your information is correct for your pack.!

Please note that the surface of the pack does not increase linearly with the heat output. that means a pack with more cells has more heat to process. therefore needs even more reserve.

but it will work. :slight_smile:

the thermal concept I mentioned is different from eppg. there are power ranges of 9 6 and 3 kw. but with long breaks in between where you fly without power. the concept makes this very possible because the sink rate is only around 1.2 m / sec if there is no thermal. with a classic eppg the sink rate is around 1.5 m / sec and you usually fly with the motor with standart eppg all the time.

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