Dual Charge Recommendations

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Horatio said:
I think there is potential - possibly - of Lithium Ion batteries having improved internal resistance and better current output.

But for FPV, freestyle, racing etc - Lion batteries aren't what people need.
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FPV guys have been using li-ion for a while now, the new generation of high current 21700 cells is a whole new ballgame. They are usually used in a 2P configuration which doubles the current capacity and makes for a less awkward form factor with 6S packs (about 85x125x71mm)

https://www.reddit.com/r/fpv/comments/1kf1tru/built_a_6s_liion_pack_with_21700

My brother just got a proper spot welder (not an aliexpresss hobbist one but a proper one) so I've been thinking about making a couple 6S2P packs out of Ampace JP40 cells for the Baja, they'll fit just fine. Should fit in the Shiroi too, but not the Asuga unfortunately they would interfere with the body (they would work with a wider battery tray that could fit the battery on it's side though)
 
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Atomic Skull said:
FPV guys have been using li-ion for a while now, the new generation of high current 21700 cells is a whole new ballgame. They are usually used in a 2P configuration which doubles the current capacity and makes for a less awkward form factor with 6S packs (about 85x125x71mm)

https://www.reddit.com/r/fpv/comments/1kf1tru/built_a_6s_liion_pack_with_21700

My brother just got a proper spot welder (not an aliexpresss hobbist one but a proper one) so I've been thinking about making a couple 6S2P packs out of Ampace JP40 cells for the Baja, they'll fit just fine. Should fit in the Shiroi too, but not the Asuga unfortunately they would interfere with the body (they would work with a wider battery tray that could fit the battery on it's side though)
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Perhaps you could compare 0-40mph times with the lithium ion Vs lithium polymer packs on the Baja?
 
Atomic Skull said:
FPV guys have been using li-ion for a while now, the new generation of high current 21700 cells is a whole new ballgame. They are usually used in a 2P configuration which doubles the current capacity and makes for a less awkward form factor with 6S packs (about 85x125x71mm)

https://www.reddit.com/r/fpv/comments/1kf1tru/built_a_6s_liion_pack_with_21700

My brother just got a proper spot welder (not an aliexpresss hobbist one but a proper one) so I've been thinking about making a couple 6S2P packs out of Ampace JP40 cells for the Baja, they'll fit just fine. Should fit in the Shiroi too, but not the Asuga unfortunately they would interfere with the body (they would work with a wider battery tray that could fit the battery on it's side though)
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Keep us posted. I was thinking the same thing about putting cells in parallel. 8 cells to build a “4s” pack. I would have done it by now but know nothing about spot welding. I have a mig welder and I have soldered nicad’s in the past (anyone remember lenon lugs?).

What is a real spot welder? Can you share what you know to maybe help me out?
 
Horatio said:
Might be realistic for RC car racing. Even in Mod 4WD buggy, I'm drawing about 120A. 'Only' 90A in 2WD - with a 5.5t motor.

So we'll find out soon enough!
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Didn’t really think of that, I guess in smaller scale rc could be bit of a game changer, Gonna give them a try then? It was Just some random suggested video caught my eye just coincidence he was from Northern Ireland also.
 
Nelson.81 said:
Horatio could be out there setting lap records people not knowing whats hit them 😝
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It's an interesting equation of power, weight and weight limit in sanctioned races. I like to get my cars as light as possible - then use 'useful' battery weight to make the legal minimum.

The nice thing - especially in 2WD - is being able to move the battery into a position that affords the best handling. On carpet, this is quite far forwards for maximum steering.

At the moment, I 'need' a battery that weighs a minimum of 171g. With the next round of modifications, I'll likely need a battery that weighs a minimum of 199g - which (funnily enough) fits the weight profile of my Redline 5300 packs.

I'm already hearing noises from certain people that my 2WD buggy is 'cheating'. 😝

31026.webp

The thing is, my buggy is about to get even lighter again - lighter gearbox, lighter arms, a load more titanium.

Lighter tabless packs would need to be an appropriate higher capacity and inevitably would end up being a different shape.

31891.webp


Interesting, lighter batteries comprised of 18650 tabless cells will likely require redesigned chassis - or highly modified chassis - to utilise the new type packs.

Before that happens - voltage under load - will need to be established. Or to put it another way - a drone pack being able to discharge 140A seems impressive enough, but the 140C Redline 2S Shorty packs I race with are theoretically able to provide 742 amps continuously!! 🤯
 
I wondered if there was a minimum weight for classes, they pretty light & fragile as they are. Thinking are the Hobbywing esc capable of running li-ion batteries. Only reason I ask I can remember Tomley rc testing some cheap Chinese car in past & depending on battery being used esc had plug had to be on different pins or didn’t operate correctly think issue was related different battery types having different voltage cut-off limits. But be interesting to see the results you big cheater 😂
 
A 6s3p li-ion pack made from 21700 cells has 3x the current output of a single component cell and measures 112 x 70 x 73mm not including extra bulk added by shrink wrap wires which makes it 1-2mm larger in each dimension. Such a pack would fit in most 1/8 vehicles with a modified battery tray and an 8s3p pack would probably be a direct fit in most 1/5 scale vehicles that use side by side 4S packs. In some 1/5 platforms you might even get an 8s4p in there with a modified battery tray.
 
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Nelson.81 said:
I wondered if there was a minimum weight for classes, they pretty light & fragile as they are. Thinking are the Hobbywing esc capable of running li-ion batteries. Only reason I ask I can remember Tomley rc testing some cheap Chinese car in past & depending on battery being used esc had plug had to be on different pins or didn’t operate correctly think issue was related different battery types having different voltage cut-off limits. But be interesting to see the results you big cheater 😂
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I switch my LVC off completely for mod racing with both 2WD and 4WD. Sag can cause LVC to kick in when it's not needed - never something you need for racing.

But yes, if the voltage sag is greater with tabless Lithium Ion batteries - LVC profiles would be different. My 2S packs are all pushing 8.9v when fully charged.

Could a 2 cell tabless battery match that?

If it can, I would expect the same punch that I'm used to - provided the voltage under load performance is the same or better.

By punch - over a 22m straight my 4.5t 4WD car has accelerated to 46 mph and then decelerated again for the right hander at the end of the straight, which all happens in around 2 seconds. Serious levels of punch. Extremely rapid.

I'm all for trying these new tabless cells - if there's an advantage to be gained. Once I see quantifiable performance specifications of these new Tabless things, I can make an educated decision.

At the moment, it's all just bluster from YouTubers.
How many drivers at the EOS euros 26 were running 2S tabless batteries?

The fact is, to all intents and purposes, lithium ion batteries are already the overwhelmingly more common choice of battery type used in everyday things like e-bikes, power tools and other cordless stuff.

Lipos are used in our niche things because of their power profile - principally explosive power delivery - is useful in electric racing cars and racing/freestyle FPV quads etc.

Tesla's tabless batteries are a game changer where many cells make up a battery.

Ampace JP30 cells are interesting. 2S 2P format with these could be a thing one day - but not until they are ROAR/BRCA approved.

https://www.cellsupply.co.uk/ampace...Re9fm2E0umCBCPIjxPiVCp43NDxltcAkkvSPEnDh_pAG3

  • Overview & Specifications
    With 3,000mAh and a 36A continuous rating, the Ampace JP30 is tailored for high‑drain systems such as EV racing prototypes where current delivery is critical. Its robust build makes it a go‑to for demanding engineers.
 
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Not sure why you would use the JP30 when JP40 have over twice the current output and are only slightly larger (21700 vs 18650)
 
Atomic Skull said:
Not sure why you would use the JP30 when JP40 have over twice the current output and are only slightly larger (21700 vs 18650)
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Why aren't you sure? I think I made it pretty clear why I (or anybody else for that matter) wouldn't be using tabless cells at this point in time for racing. Regardless of 18650 or 21700 size.

140C 2S HV Lipo are legal and deliver more beanz.

A 5300, 140C 2S Lipo can deliver 742A continuously (in theory) and have a higher voltage. (My 2S cells were peaking at 8.9V Vs JP40 2S1P configuration 8.4V).

JP30 - in 2S1P configuration can deliver upto 52A continuously.

JP40 - in 2S configuration could provide 60A

Voltage stability under load looks to be promising with these new tabless cells, but it's too soon to state with any certainty that they're going to replace 2S lipos for racing, whether that be for stock or modified classes.

We've just had EOS 2026. We're still at the talking stage.

Next will be the feasible stage.

Then will be the sanctioned for racing stage.

Perhaps then - we'll see chassis designed for the new Tabless batteries.

We're at least 2-3 years off that for racing - the actual rigs would have to catch-up first.
 
Horatio said:
JP40 - in 2S configuration could provide 60A
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I'm more concerned with bashing than racing so my priorities are different.

EDIT: JP40 cells can actually handle up to 70A discharge as long as the temperature remains below 80c
 
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AggyMi said:
Anyone have any recommendations for a reasonably priced dual output charger. Been looking at something like the SkyRC T100 , anyone have experience with it or other recommendations
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Wow,just reading through the comments, this post has got seriously of track for someone just asking a question about a dual charger 😳
 
I'm currently using a sky 100 dual neo,it does a reasonable job at charging but will only go to 6.7w per chanel when charging 2, 10000mah packs on ac feed.
Total pita with the connections though,short balance leads are a problem even when using custom made long cell charge leads,ive just ordered the pro quad charger purely because it comes with all the balance boards with long wiring,i know it only does 7.4 w per channel, but the unit is well priced compared to the sky rc q4000 which I would have preferred but is way more expensive.
 
mrBigpitts said:
Wow,just reading through the comments, this post has got seriously of track for someone just asking a question about a dual charger 😳
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Thread was done by page 2 and the discussion naturally branched into other subjects - like batteries.

To be brutally honest, rather than skirt around the subject - thread drift is the least of the problem on this board. To make it about that would be disingenuous.

PM me if you would like to discuss further. 👍
 
Horatio said:
Thread was done by page 2 and the discussion naturally branched into other subjects - like batteries.

To be brutally honest, rather than skirt around the subject - thread drift is the least of the problem on this board. To make it about that would be disingenuous.

PM me if you would like to discuss further. 👍
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There wasn't a question mark at the end of my reply, it was just an observation on the original post.
Thank you for your input.
 
Is a question mark mandatory for a conversation? Is that what you are inferring?

I think not. If it was, we might expect a moderator to chime in.

Members don't need an invite to discuss matters raised. The OP raised their question. Others took turns to make statements.

The thread (like many others here) drifted, but that really isn't an issue in general, once the initial questions have been answered.

Take a deeper look at what certain individuals are posting and you'll see what I mean.
 
Atomic Skull said:
I'm more concerned with bashing than racing so my priorities are different.

EDIT: JP40 cells can actually handle up to 70A discharge as long as the temperature remains below 80c
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Reply - even 70A (debatable from the specs I've seen) isn't anywhere near enough for our 4S - 6S Rigs.

It's not really a racing Vs bashing matter. It's more a case of whether you think 60-70A is an acceptable limit for your surface model.

If it is - fill yer' boots! (And let us know how it goes).
 
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