Run two lipos stacked or side-by-side?

[DaniC]

Hey guys,

I've never ran 2 batteries in series before, I want to run 6S on my XTR and I think I'll be better off with 2 x 3S batteries as opposed to a single 6S one.

What I'm trying to figure out is if it's better to run the batteries vertically side-by-side, or horizontally one stacked on top of the other.

In my mind vertically makes more sense because you don't have the weigh of the top battery pressing against the bottom one on landings etc, and also there's no risk of the top battery sliding forward.

The battery tray on the XTR is 161x51mm. This means is way easier to find batteries that would go stacked, because for them to go vertical they'd each have to be 25.5mm max. This Team Corally packs looks like they would fit perfectly side-by-side.

So what do you think, side-by-side or stacked?

 

[KnowAir]

I have 5200mah 3s soft packs. I can't fit them side by side and the battery tray isn't tall enough to hold them stacked securely IMO. My guess is that you would need something like 4000mah or smaller to fit side by side, not sure as I don't have anything under 5000mah myself.
I ended up modifying the tray with a taller stop and an additional strap runnining front to back so I could stack my 3s packs. I don't do big jumps so I wasn't as concerned about the vertical force impact so much. Here's a picture of what I did, some aluminum angle stock. I think it's 6000 series. I removed the stock plastic stop and mounted the taller aluminum angle in it's place. I'm sure hard case would be a better choice(always).

I've since given up on 6s(for now) since the drivetrain started showing rapid wear on 6s. Mine is the '21 model so it doesn't have the swiss miss drive parts..I plan on upgrading to swiss miss eventually but replacing all the cups,shafts and outdrives isn't in the budget right now so 4s it is..

Edit: the picture above is actually 5s, one hard case 2s and 1 softcase 3s..but 2x3s does fit pretty well too.

 

[DaniC]

I have 5200mah 3s soft packs. I can't fit them side by side and the battery tray isn't tall enough to hold them stacked securely IMO. My guess is that you would need something like 4000mah or smaller to fit side by side, not sure as I don't have anything under 5000mah myself.
I ended up modifying the tray with a taller stop and an additional strap runnining front to back so I could stack my 3s packs. I don't do big jumps so I wasn't as concerned about the vertical force impact so much. Here's a picture of what I did, some aluminum angle stock. I think it's 6000 series. I removed the stock plastic stop and mounted the taller aluminum angle in it's place. I'm sure hard case would be a better choice(always).

View attachment 2450

I've since given up on 6s(for now) since the drivetrain started showing rapid wear on 6s. Mine is the '21 model so it doesn't have the swiss miss drive parts..I plan on upgrading to swiss miss eventually but replacing all the cups,shafts and outdrives isn't in the budget right now so 4s it is..

Edit: the picture above is actually 5s, one hard case 2s and 1 softcase 3s..but 2x3s does fit pretty well too.

Those Team Corally packs I linked above actually for side by side and they're 6000mah! Seems like a pretty good option.
My hope was to run it on 4S but it's getting too hot so my hope is that the extra volts would remedy that as discussed on another thread.

 

[KnowAir]

Those Team Corally packs I linked above actually for side by side and they're 6000mah! Seems like a pretty good option.
My hope was to run it on 4S but it's getting too hot so my hope is that the extra volts would remedy that as discussed on another thread.

Ah, I see that now.. sorry, I didn't follow the link before. They look alot like the TRX batteries..long and skinny. If TC say's they fit, I'd have to believe that. One day, I'll stop being such a cheapskate and pay for some "quality" batteries.. but, till then, I'll have to MacGyver my rigs to fit the crap I have on hand

I just bought 2 3s 5500mah (80c) Sypom batteries off of Amazon for $37.. had to swap the Dean's for XT90's but I have bags of XT90 connectors. So far, they're pretty impressive(to me).. I know there's no such thing as 80c, but they seem to have plenty 'O punch for the price. There's a giant thread on RCTECH about the "C" ratings of lipo batteries..the jist is that there is NO battery in the world that can deliver more than "45C"..

 

[slick2500]

Ah, I see that now.. sorry, I didn't follow the link before. They look alot like the TRX batteries..long and skinny. If TC say's they fit, I'd have to believe that. One day, I'll stop being such a cheapskate and pay for some "quality" batteries.. but, till then, I'll have to MacGyver my rigs to fit the crap I have on hand

I just bought 2 3s 5500mah (80c) Sypom batteries off of Amazon for $37.. had to swap the Dean's for XT90's but I have bags of XT90 connectors. So far, they're pretty impressive(to me).. I know there's no such thing as 80c, but they seem to have plenty 'O punch for the price. There's a giant thread on RCTECH about the "C" ratings of lipo batteries..the jist is that there is NO battery in the world that can deliver more than "45C"..

There were some that could do around 50C but they could not sustain that over multiple test so he changed his testing method to see the highest sustainable C rate and all the batteries dropped down about 5-10c.

This was his test summary from 2019

This is his most recent with the modified testing.

I didn't even know Team Corally made their own batteries. That is pretty cool that they do.

 

[Koma71]

operation
• Before using the battery, use a voltage tester to check the voltage of the individual cells to prevent damage. The voltage deviations should not exceed ΔV 30mV.
• Never discharge your battery below 3.0V/cell during operation, otherwise there is a risk of fire and explosion. Calculate your operating time DoD (Depth of Discharge) (=capacity/measured power consumption) and plan a reserve of at least 10-15%.
• Make sure that the temperature measured on the cell surface does not exceed 60°C after discharging/operation. Approx. 25°C to 40°C are optimal. Check the change to Swaytronic high-performance cells (>60C) if the battery gets too hot.
• Extend the EoL (End of Life) of your battery by always leaving at least 20% of the energy capacity in the battery. For example, with a 2500mAh battery, don't source more than 2000mAh and keep in mind that the maximum capacity of the battery will decrease over time.
security and performance
in dealing with lithium polymer batteries Swaytronic (Switzerland) AG

SWAYTRONIC
Belastbarkeit Stecksysteme
EAN
7640159363323 7640159363330 7640159363347 7640159363361 7640159363354 7640159363378 7640159363385 7640159363392 7640159366423 7640182626631 7640159363408 7640159369202 7640159363415 7640159363422 7640159364108 7640159363439 7640159363446 7640182624811 7640159363453 7640159363460 7640159363477 7640159368823 7640182623425 7640182626600 7640159363484 7640159363491 7640159365907 7640159366454 7640159363507 7640182627201 7640159366447 7640182626068 7640159363514 7640370542125
Die nominale und kurzzeitig maximale Strombelastung der Stecksysteme varieren sehr stark, da hier verschiedene innere und äusser Einflüsse eine grosse Rolle spielen. Zum einen hat die Umgebungstemperatur einen grossen Einflus auf die Strombelastbarkeit aller Stecksysteme. Durch eine steigende Umgebungstemperatur und oder Wärmestau in der Applikation sinkt die Belastbarkeit, bzw. die Leitfähigkeit.
Ebenfalls wichtige Indikatoren für den maximalen Stromfluss ist das Alter des Stecksystems und dessen Gegenpar, sowie der Zustand und die Sauberkeit. Weist der Stecker an den leitenden Teilen.

Stecksystem Dauerlast in A Spitzenbelastung in A

2.5mm Gold platted plug 20A (15A - 35A) 35A (20A - 45A)

3.5mm Gold platted plug 35A (25A - 45A) 50A (40A - 70A)

4.0mm Gold platted plug 75A (60A - 95A) 100A (80A - 150A)

5.0mm Gold platted plug 100A (80A - 135A) 160A (140A - 200A

5.5mm Gold platted plug 10 pair / bag 120A (100A - 160A) 200A (180A - 250A)

6.0mm Gold platted plug 150A (125A - 175A) 250A (220A - 290A)

7.0mm Gold platted plug 180A (165A - 200A) 300A (250A - 340A)

8.0mm Gold platted plug 280A (250A - 340A) 400A (370A - 460A)

Plug AS150 180A (165A - 200A) 300A (250A - 340A)

Plug AS150U-F & Plug AS150U-M 180A (165A - 200A) 300A (250A - 340A)

Plug Dean T-Plug 10pair / bag 70A (50A - 110A) 120A (100A - 165A)

EC2 Plug System 5pairs / Bag 25A (15A - 35A) 40A (30A - 55A)

Plug EC3 35A (25A - 45A) 50A (40A - 70A)

Plug EC5 120A (100A - 160A) 200A (180A - 250A)

Plug HXT6.0 150A (125A - 175A) 250A (220A - 290A)

Plug HXT3.5 35A (25A - 45A) 50A (40A - 70A)

Plug HXT4.0 75A (60A - 95A) 100A (80A - 150A)

Plug Futaba RX / JR 5A (3A - 12A) 8A (6A - 16A)

Plug JST 12A (8A - 22A) 20A (16A - 30A)

Plug Mini Tamiya 20A (15A - 35A) 35A (20A - 45A)

Plug MPX 35A (25A - 45A) 50A (40A - 70A)

new Dean T-Plug with protection 70A (50A - 110A) 120A (100A - 165A)

Plug PHR-2P 5A (3A - 12A) 8A (6A - 16A)

Plug PHR-3P 5A (3A - 12A) 8A (6A - 16A)

Plug Tamiya 25A (15A - 35A) 50A (40A - 70A)

Plug Traxxas 80A (65A - 100A) 140A (115A - 165A)

Plug XT150 150A (125A - 175A) 250A (220A - 290A)

Plug XT30 30A (15A - 45A) 45A (35A - 65A)

Plug XT60 60A (45A - 80A) 100A (80A - 150A)

Plug XT60H - black 60A (45A - 80A) 100A (80A - 150A)

Plug XT90 lightning 90A (75A - 120A) 150A (130A - 175A)

Plug XT90 black 90A (75A - 120A) 150A (130A - 175A)

Plug XT90 90A (75A - 120A) 150A (130A - 175A)

Plug QS8 120A (100A - 160A) 200A (180A - 250A)

The nominal and short-term maximum current load of the plug-in systems vary greatly, since various internal and external influences play a major role here. On the one hand, the ambient temperature has a major influence on the current carrying capacity of all connector systems. The resilience or the conductivity decreases due to an increasing ambient temperature and/or heat build-up in the application.
Also important indicators for the maximum current flow is the age of the connector system and its counterpart, as well as the condition and cleanliness. Points the connector to the conductive parts.

 

[KnowAir]

I was just browsing the Swaytronic website, are these batteries made in China? Just curious. They are quite pricey by comparison to what typical China lipo's sell for here in the US. It is nice to see more respectable "C" ratings vs the hyped up numbers typically claimed here (US) though..

 

[DaniC]

Loads of stuff on that website. I think the next time I need to buy lipos I'm going with CNHL, only issue I see is that stock availability in the EU warehouse is very scarce.

Anyway, back to the original question. I guess most people run their batteries stacked so it's probably not an issue. And whenever there's not enough support from the tray for the top battery just run a good strap lengthwise.
BTW, speaking of straps, these are my favourites, they're virtually unbreakable.

 

[Koma71]

Swiss Made !!!

 

[KnowAir]

Loads of stuff on that website. I think the next time I need to buy lipos I'm going with CNHL, only issue I see is that stock availability in the EU warehouse is very scarce.

Anyway, back to the original question. I guess most people run their batteries stacked so it's probably not an issue. And whenever there's not enough support from the tray for the top battery just run a good strap lengthwise.
BTW, speaking of straps, these are my favourites, they're virtually unbreakable.

They do look robust

 

[slick2500]

I was just browsing the Swaytronic website, are these batteries made in China? Just curious. They are quite pricey by comparison to what typical China lipo's sell for here in the US. It is nice to see more respectable "C" ratings vs the hyped up numbers typically claimed here (US) though..

Most if not all of the rc li-po batteries are made in China. https://www.made-in-china.com/manufacturers/rc-lipo-battery.html

I cannot find any specifics on Li-po batteries only Li-on.
China dominates battery production today, with 93 “gigafactories” that manufacture lithium-ion battery cells, vs. only four in the United States