Looking forward to it!
Just guessing, but the JST connector probably has 15 connections? one for ground, and then one positive for each cell.
Can you confirm that?
If yes, this is for charging and balancing.
My 13S15P Setup with Lithion Ion 18650 cells got too hot on my very first flight, so as you are probably aware, I built an aluminum case with fans for active cooling. I am afraid that this may happen to your battery as well, as it is tightly sealed.
I will be extending my battery to 13S20P within the next few days, to ease off power consumption from the individual cell on full throttle as an additional measure to keep the battery safe and operational for a long time.
I like the Anderson connector though, much more decent than the RC Pro Plus connectors that I used…
Chris says my battery should stay cool as it is overbuilt for the openppg specs. I’m sure full throttle non stop would overheat. Time will tell how it really works.
I’m not sure what cells they used though as they said it would be Samsung 25r. These are 2.5ah cells but this battery is 14s16p and 55ah which means each cell is 3.5ah. Unless they got the info wrong on the sticker.
The jst connector has five wires not for balance charging as the bms balance charges it. It’s for the Bluetooth adapter that came with. Can’t seem to get it to work though with the Xiaoxiang bms iOS app. It connects but doesn’t show any data.
Yes the Anderson connector is very nice. Just big but it’s a lot of power going through one connection. I’ll be shortening the battery leads as they are too long.
Let us know how it goes!!
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Configurations: 14s16p li-ion battery
Specification: 52.8v 55ah
Cell type: Samsung 35ET cells
Continuous current: 200A
Peak current: 350A
The power switch you could remove from the battery case and run it somewhere else to your remote or something to turn the battery power/kills switch on/off, But this first battery its mounted in the battery
Battery pack is weather resistant for rain, and the on/off switch, and backlit LCD are also waterproof.
It should work well!
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Hmmm, see my reply here… At full throttle we are over 300 amps discharge…
There will be a huge voltage drop at full throttle - which could engage the BMS.
With 4 x 22000 Bonka’s we have 1100 Amps continuous current…
Hope it will work out for you!
Based on the C rating you should be able to draw that much current from the Bonkas but that is far from reality. When I fly level flight I draw only between 120 to 140 amps. After 25 minutes of level flight the packs get up to 55 Celsius. Lipos should never be taken above 60 Celsius. If you ever pulled 1100 amps from four Bonkas you would have serious problems to deal with.
I think the battery from Chris might be pretty equivalent to 4 Bonkas because the specs from Chris are probably more realistic. Anxious to find out.
All setup now and ground testing done. Seemed to be no issues. Pushed to about 80% for few min and battery was at 16°c with temp gun. I need to get android phone so I can read data off the bms via Bluetooth, it should give me more accurate readings of battery specs. Ready to fly next nice day and with some help from paramotor friend for first flight.
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Looks like another great build and… wow, now you can really see the dimensions of the connectors. These are real beasts!
Good luck on your maiden!
@VeConcepts and @dzubot do you have thermistors (temperature sensors) inside, inbetween the individual cells built in and controlled by the BMS?
You say the battery had 16°C , but that’s measured on the outside of the case, which may be a big difference to the inside.
When my BMS shut down the battery pack at 65°C after a 9 minute flight with 80% throttle, the outside was not warm at all (I insulated the battery with foam rubber and stretch wrap) but the inside measured 65°C.
I just don’t want you to destroy your battery or even have it catch fire due to a thermal runaway on your first flight!!!
I am at far no expert, but I spent a lot of time reading everything about Li-Ion batteries, this forum here plus the experience from my own tests - which lead me to spend another 700 Euro on an aluminum case with active cooling and another 5 parallel groups to be added soon to my pack.
Just because the OpenPPG demands so much power…
Appreciate the concern. I’m hoping it does. Picking up friends old android phone today so I can see the bms readout, this should tell me the internal battery temp when flying and each series voltage.
@dzubot, Any new updates on the battery testing? Have you had the opportunity to flight test it yet?
Unfortunately this battery was not built correctly and is being returned to VeConcepts. During testing the battery was shutting down at 200amps, this is well below what we ordered. We were told the battery was good for 200amp continuous 350 peak, but not the case. My guess is the battery is 120amp continuous 200 peak since they also switched the cell type to samsung 35ET? I cannot find any info on these cells only 35E which have 8amp discharge. We were told it would ship with 25R cells. No hard feelings to Chris @VeConcepts as he was told they could deliver what we require but that did not happen. Chris has been great in trying to remedy the solution with the battery manufacturer in China.
@dzubot contacted me via PM, which is totally fine, but I prefer to give the answer here, so that others can profit from it as well.
I plan to build an 18650 pack now as I already have the same 300 amp bms you bought. Are you happy with the BMS?
It took me a while to figure out what is important.
You definitely need to use the App (with an android based smartphone, I think) to configure the BMS.
You need to set the amount of cells you have (13S in my case) and you need to reconfigure high and low voltages, at what voltage the individual cell is considered full - and at what voltage the battery is considered empty. For the LG HG2 this is 4,2V full and 2,5V empty.
I also had to reset the max amp to 360A instead of 300A - the BMS is only rated for 300A, but I haven’t had any trouble going full throttle for a couple of minutes, which definitely draws more than the 300A for which the BMS is rated.
What is really great, I don’t have to fiddle with the sparking or arcing with those switches. I just left them out, as a simple push of a button turns the battery on and off.
Happy with the LG HG2 cells? They are on sale now at IMRbatteries.com.
I don’t have any experience with batteries. I just did the math and found out, that for a minimum amount of cells (13S15P, which I later extended to 13S20P), the LG HG2 were the only ones that would have the correct technical specifications (Amp Draw). I purchased the cells for under 5 dollars directly in Asia. voltaplex.com or batterybro.com - they ship via UPS and DDP (delivered, duty paid).
I’m thinking either 14s18p or 14s20p battery, what are your thoughts?
when I decided to go for 13S15P only very little information and virtually no experience was available from the community - Today I know that the ESCs and motors would also support 14S. If I would build another battery, it would probably be a 14S - but 13S works as well.
Oh and i’ll be using a prototype vruzend connector
I looked at those back then, but decided that they would not support the amp draw.
Also the price was an issue - the price for a vruzend kit was about the same as for the spot welder plus nickel strips. The soldered connection is also better for higher amps, as “soldered connections” are really tight and good.
I don’t know about the new prototype, that you mentioned. I guess you just need to decide for yourself.
Any tips would be appreciated since you’ve gone through this process. Would you change anything, different cells etc?
I would still go for the high quality cells LG HG2, even though I would probably go for 14S, 20P or even 25P, which means there’s less stress for each individual cell.
The fans that I added are not really needed, the way I designed the case, the cells are very well ventilated even without the fans.
I would probably also go a different route for a case, the 600 Euros for the aluminum case are really killing it. With a little more time I would probably have been able to design a similar case made out of custom bent aluminum sheets or so…
I had a huge voltage drop on the battery from veconcepts, like 8v drop i’m assuming this is because they used cheap cells.
I don’t know, I am not experienced enough.
what I noticed is that after I added another 5 parallel groups (15 to 20p) the voltage drop wasn’t so significant anymore.
Curious where you got your cells and what price?
voltaplex/batterybro around 4.50 dollars plus shipping
Do you notice much heat on your 7mm connectors from battery to the openppg?
the connectors that I used are rated for 160A per pair, so I used 4 x 8AWG wire and 4 connectors (2 per terminal obviously - you can see that on my photos that I posted here:
Heat is no problem at all on the wires or connectors. Probably because everything is so well ventilated.
If I would build the battery again, I would probably search for different connectors - the anderson plug that you have from that veconcepts battery looks very solid, and probably much easier to connect to the cables then those RC Pro Plugs that I used…
How does the Bluetooth connection work to your bms through your battery box, is it solid?
No complaints on the bluetooth connection - the only problem I had when monitoring the cell voltages and temperature is that my phone kept switching off, and I was too lazy to find and change the appropriate settings. When you’re in the air, it’s a bit difficult to push the “on” button and enter the pin code 
I very much appreciate the response to the questions. So this is what I’ve decided and ordered.
Battery 14s20p (60ah, 3528wh)
Lghg2 cells, ordered 282 at $3.99 per cell from Imrbatteries.com
Ordered 300 vruzend caps (30 in a pack)version 2.5. Tested up to 32 amp draw per cell, and from what I am told have better flow through of energy vs spot welding. Got a good discount as they are prototype stage on these caps. The new caps also have new design to bolt them together so there is no chance of caps working loose. Going this route as it is easiest to add more cells if needed, I just like the idea of how simple they are.
I already have the same 300 amp bms as you ordered, thank you for the suggestions to change settings on the app.
Couple questions, where or how did you mount the on/off switch? I’m thinking of running it to the throttle and installing an on/off switch inside the throttle for easy access.
How did you wire the leads from the openppg, did you wire so two motors are on one of the battery leads?
Great info on the battery case, another reason I like the vruzend connectors is there is a nice air gap between the cells, which should help dissipate heat, I’m thinking will build plexiglass box and drill many holes for ventilation.
please share whatever you have been shown (photos / 3d Renderings ?) as I am curious (and others probably as well) what this is about.
I soldered the button to a long wire that I am guiding along the left shoulder strap to about where my chest is. it is for now just dangling off from the should strap, secured to the same. I can easily reach that button and turn the whole battery on or off very easily during flight (even though there is no reason to turn it off, as there is no energy consumption when the throttle is not pressed.)
On this photo you can see how the wire is coming out of the case:
You can also see the four main power cables.
the other black cable that you can see coming out of the same opening is just a loop and the negative terminal of the three fans. I later added a switch to be able to turn the fans on and off (for charging they need to be turned off).
I did it the same way as @GliderPilot, except for the two switches, which I can just leave out of the equation, since the BMS does the on/off switching. Here’s a photo from his build log:
When I was thinking about my case, I had plexiglas (acrylics) in mind as well, but others suggested to not go for acrylics, as it is very brittle, but to better go for polycarbonate. However I did not find anyone who offered to lasercut polycarbonate - I then went the aluminum route - but air gaps and good ventilation is definitely the right thing to keep in mind!
I think I might need to redo off my wiring now as with the battery from Veconcepts had single 6gauge wire, I’m leaning towards doing it the way gliderpilot/you did as this would split the load on the wiring coming from the battery instead of having one heavy lead with no disconnect switches. I just don’t know how I would connect a heavy lead to these vruzend connectors.
Here are a couple pics sent to me by vruzend of the new connectors.
Here is a picture of how I was thinking to use some type of plastic board to cover the batter cells while leaving the sides open for the battery to breath. Now that these new connectors have path throughs for bolts it would be very easy to install.
I’ll start new thread on my battery build as the components arrive.
Got the new prototype vruzend 2.5 connectors that have been tested to pull 30amp continuous. They look pretty awesome! Time to build my battery.
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I am really looking forward to what you will build