13S15P Battery Pack Build

Awesome! I wasn’t aware that VeConcepts is already providing a battery solution compatible with OpenPPG. Did I miss the announcement somewhere?

I look forward to seeing the pictures!

I don’t have the battery weight as it hasn’t been built yet and they probably don’t know what it’ll be until it’s done. But I’m guessing it’ll be around 35lbs based on how many cells there are and they weigh 45grams per cell.

No official battery announcement I’ve been working with Chris to get this first battery made. I’ll be the guinny pig for others to benefit from any changes that might need to happen before more are produced. I’m sure if you really wanted the battery now though that they would make it for you now if you don’t want to wait to hear how it works from me. Also don’t hold these prices for what you might pay, I just wanted to share what I paid but as like anything the price could change on the next one, I’m all for transparency. Innitially I was quoted about $1500 for a 45ah pack that had 300 amp max discharge and 120 continuous. The 55ah pack has much better specs for this paramotor, hoping it’ll stay nice and cool and can run full throttle for decent amount of time.

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I don’t want to critizise here, but based on my first 9 minute flight, with the battery overheating, I’d be cautious.

I have ordered another 65 cells which I will add to the already existing 195 cells, so this will be a 13S20P Setup, and the high load is spread over 5 more parallel group.

The Lithium Ion was a good choice, in my opinion, but this cell chemistry has one big disadvantage over the LiPo pouch cells: the lower discharge rate (Amp draw).

Regarding the veconcepts solution:

  • which cell is used? there are not that many that have high discharge (the LG HG2 that I use has 3000 mA with 20C, so my 15P setup is the minimum required for a 300A continuous discharge. Full throttle apparently goes up to 360A on the 13S/48 Volt battery

  • a proper BMS is a Must for charging, and is advisable for discharging. Is one included?

  • so the “case” is a shrinkwrap only? … I am not so sure about this. I did not only use shrinkwrap, but that foamed rubber additionally (which added not only extra protection, but a bit of thermal insulation). But that setup overheated on 80% throttle right after 9 minutes, and that on a cold day!
    I have ordered an aluminum case now with vent holes and three strong fans to pull lots of air through in between cells for cooling.

Hi etienne,

I fully support the scrutiny and appreciate your comments. This is the only way we can improve our battery systems.

So this is a 14s 55ah battery pack using Samsung 25r cells. Let’s divide 55 by 2.5ah per cell, giving us 22. So this is a 14s22p pack. Take 22x14=308 cells total. Each cell rated for 20 amp continuous. So 22cellsx20amp=440amp max continuous. So they are being generous with the 350 amp number.

The battery will come with a bms that supports 350amp continuous output power, as well will charge the pack. Chris says this pack will stay cool but testing will confirm this.

Your pack most likely is a little too small plus the insulation didn’t help. I’ll most likely build something to protect the cells, possibly an open ended case out of plexiglass.

I’m interested in this case you ordered can you share where you got it, did you custom design it?

Since you are using 160 Kv motors for the 14s configuration, doesn’t this also imply that the Amp draw will be lower as well?

I think I might see slightly less amp draw. Lower kv motors have thinner wire for higher voltages and less amp draw so in theory I would think I should see a slight decrease.

Actually, to use 14S instead of 12S the motor that would give equivalent power would be 150 KV. With the 160 KV he may have to lower the prop pitch to prevent from drawing too many amps at full throttle. Then he will have higher volts and lower amps at the ESC and motors and wires with the same power as the standard 12S system.

As for the battery itself the only way to reduce the amps per cell is to have more cells. No matter how you arrange the cells in series vs parallel each cell still does the same amount of work for a given load and a given cell count.

Good point. If I am drawing too many amps at full throttle I’ll have to try the 22x8 props

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I used Schaeffer AG Gehäuse - they originally started with a front-plate designer (for custom housings) but in the meantime they extended to build complete custom cases.

You can download a software from them where you enter the three lengths, and a script creates a case out of it, where you can place holes and such.

They also have a USA based partner/daughter: http://www.frontpanelexpress.com/

warning: it’s not cheap … but to get a quick and functioning solution I decided to go for it.

Please post pics and your thoughts on the case when you receive it. How long does it take to get? Can you share cost paid?

Darryl, just posted a couple of pictures and information.
I did put it into a new thread though:

When you charge your battery up with this bms, how are you doing it, just using one of the two battery + - leads? Or did you make a Y cable so that power is going through all four battery leads? Curious what amperage charger your using and how long it takes to charge? I ordered this 10amp one. https://www.amazon.ca/gp/product/B078MYP68W/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

when I bought a charger, I did not really think about it or even calculated any charge times.
I bought a simple ebike changer with the correct voltage. They had two choices 4A and 6A.

As I said, I did not think much (which I really should do more, before I take decisions), so I just decided, let’s take the 6A one. unfortunately, logically 6A is still not much, so it does take quite some time, probably around 7 hours?

I think, however, it would not make much difference: If I want to go fly, I either have charged the battery, or I haven’t :-). If I haven’t, then it does not make a difference whether I have to wait 7 hours or 5 hours :slight_smile: … the day will be over.

In regards to charging: I just connect to either one of the red and black one. It does not make a difference, charging current is so low, and all four cables go to the same battery, so no need for a Y-connector.

That’s pretty much same thought I had. No need to buy a high current charger since it’s hard on battery plus won’t be charging it up at a field.

Thanks for info!

Also do you push your battery to the max lower voltage of 2.5v? Seems to be conflicting information online about 2.5v being the min vs 3v being min for 18650 cells. I know the manual says 2.5v is minimum. I’m guessing the 3a capacity of lghg2 was calculated by using voltage range of 4.2 to 2.5 so if we don’t go down to 2.5 then we are not utilizing full capacity of the pack.

yeah, I’ve set the minimum at 2.5V.
That’s what the specs of the LG HG2 says.

info about 18650 cells in general is not as relevant as the specific specs sheet for the LG HG2

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4153412281. kevingraehl@gmail.com

Or here.

Who did you laser cutting?

I need to cut nickel
@etienne

You’re referring to the cutting of the nickel strips, that I did a while ago?

As I mentioned, I have access to a fibre laser that can engrave metal and even cut it if it’s not too thick.

The laser system is used in the business that I happen to own: www.looxis.de

Gotcha. I’m looking to buy a fiber laser. Here in the USA, ship from China.

Cutting .2mm Nickel and copper

Or even better, a last that will fit in my shapeko xxl

50 watt?

Is that minute/pound a minute of climbing, or a minute in the air (including gliding down), or a minute in the (including catching thermals), or … ?

That’s with the most conservative flying and is time in the air. With no other lift (late in the evening when the air is most calm) if you hit full throttle up to 3000 feet and then glide down your flight will be a little shorter than if you maintain level flight under power the entire flight.