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Misterp180

Can a NIMH fit in a shortie LiPo RC

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Hi everyone,

Looking for some advice here. I am fully aware of the debate on NIMH vs LiPo performance but for my requirements at the moment I am only planning on using NIMH batteries.

Looking at some higher end RCs I notice they are fully designed for shortie LiPo batteries these days. Is it possible to build a 6 cell NIMH that would fit or am I just going to have to wait until I am ready to upgrade all of my batteries to LiPo?

Any ideas would be great. I have been looking at the Team Associated and Schumacher race buggies but don’t want to commit and then find I have no choice but to go LiPo.

Thanks Tamiyaclub members 🙌🏻

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No.

The shorty is a similar size to the old 4-cell NiMH batteries but obviously the voltage is far too low to compare.

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NiMH cells come in fractional sizes too :) 

like T made a shorty pack for the Tyrell 6-wheeler when it was first rereleased using 2/3rd height cells so a 6N (3x2) is length of 4 (2x2) full height cells.

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While it is possible to build smaller NIMH packs out of smaller cells like say AAA sized cells, the question is can they provide the sustained C required? When you said "high performance", I assume also high performance motors? For example, my lipo shorty has a 140C rating for a 3000mah capacity giving 420A (more for burst), I doubt AAA or even AA cells can do that. Also, another question is capacity. AAA cells typical have a capacity of 350 - 1000mah, that is really low. 

EDIT: A 3 X 2 AAA pack will be about 31.5 x 21 x 44.5mm (excluding wrapper) while a AA pack will be 42 x 28 x 51mm. A shorty lipo is 47 x 19 x 93mm. If you are creative, you might be able to build a 6S2P pack out of AAA and still fit. 

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Nobody’s talking AAA or AAs unless you’re building packs for Tamtech/MicroRS4/MiniZ :P

BiTD actually tried... took 3x AA in parallel to keep up with 1 subC nicad. Yeah 6s3p AAs :lol: didn’t really save any space. But my starterbox ran ok on “36 cells” :rolleyes:

SubC 1/2 or 2/3 pump about half current capacity as full subC. 

“A” batteries are still a commercial size too. 

But you might as well use 18650 for 2s1p smaller packs. 

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57 minutes ago, WillyChang said:

But you might as well use 18650 for 2s1p smaller packs.

OP did state that no lipos. If lipo is within his consideration, just get a shorty and be done. No need for this question to begin with. 

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2 hours ago, alvinlwh said:

no lipos

18650 is a LiFe I think :P definitely not a baggy lipo :lol:

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4 hours ago, WillyChang said:

18650 is a LiFe I think :P definitely not a baggy lipo :lol:

I have a dozen or so 18650s and none of them are LIFE (lithium iron phosphate), they are Li-Ion. They are all 3.7V not 3.2V of LIFE. 18650s comes in INR (hybrid), INR (lithium manganese), ICR (lithium cobalt), etc varieties, but never seen one with 3.3V of LIFE. 

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@Misterp180  I was going to say, I run tiny 6 cells in my 1:18... so it can be done.  However, the capacity is small as they were intended for much smaller motors.

 

You can run LiPo safely, you just need to keep an eye while charging, don't leave it in the charged state for too long, and maintain the storage voltage 3.75 - 3.85v range.. you're pretty much set.  They keep storage voltage for years at a time..  

I suggest you use this as an opportunity to try LiPo and learn the basics.  :D   In my case, I don't like waiting for a long time to charge (nor enjoy looong driving run times as I get tired) so only buy smaller capacity batteries.  GL with whatever you decide!  

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Thanks to everyone who has replied to my post 🙌🏻 My limited understanding is that I can change the configuration of a NIHM pack to stack the cells differently so I will investigate with the dimensions to see if I can get it to work.

I was looking at the cell sizes and I assume if I drop below the standard sub C there will be a performance drop? 
 

The idea was to try and avoid needing to buy new chargers etc and just create a pack I could use in more modern buggies that only take shortie packs until I am ready to make the leap to LiPo throughout the fleet. 

Perhaps I will consider the LiFe batteries as a trade off. Although I will probably need new chargers then anyway so would perhaps be better just jumping to a LiPo to try? Perhaps a hard case and a batbox might make me feel more relaxed?? 

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10 hours ago, Misterp180 said:

Although I will probably need new chargers then anyway so would perhaps be better just jumping to a LiPo to try?

My lipo journey is a stranger one. I had been called an idiot by a friend for not going lipo, but not because I do not want to change chargers but because I live in a place where I cannot just pop into a shop and buy one and it is (mostly) illegal to post one to me. I eventually got some lipos through some complicated logistics arrangement. 

Now, you can get a basic lipo charger for not a lot of money. I got a ToolkitRC one off Aliexpress for around £25 that has balance and storage charge (but no storage discharge). It powers off USB-C QC or PD, which most of us already have around the house for charging useless things like phones and laptops. 

For me, the difficult part at the beginning was swapping all connectors over from the Tamiya one, but I got better at soldering as I went along. 

So if you can easily buy lipos, give it a try. Maybe even just for that one buggy. You might change the rest over in a future date. 

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@Misterp180 Honestly if the car is calling out LiPo, I would go LiPo.   Once you start going off on tangents it starts adding unnecessary costs.

As alvinlwh mentioned above, LiPo chargers can be had for an economical price.  And I suppose if changing over the battery connectors is a challenge, you can either make one adapter or buy one that goes from say DEANS to Tamiya (for example) and use that across the board.  

Actually I made all sorts of adapters to go from different battery connectors to accommodate all sorts of batteries.  Even today I use an adapter between the DEANS to Tamiya as my on-road m-chassis all run DEANS and my off roaders mostly run Tamiya.. and no plan to switch them over as I want my Tamiya cars to run Tamiya battery connectors just from a vanity point of view.

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8 hours ago, Willy iine said:

@Misterp180 Honestly if the car is calling out LiPo, I would go LiPo. 

Exactly this. Race chassis are built for LiPo. It's like buying a Porsche and then converting it to run on used cooking oil.

  • Haha 3

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16 hours ago, Willy iine said:

Honestly if the car is calling out LiPo, I would go LiPo.

I used lipo in a Lunchbox and it became totally uncontrollable! 😁

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7 hours ago, sosidge said:

Exactly this. Race chassis are built for LiPo. It's like buying a Porsche and then converting it to run on used cooking oil.

Umm... don’t laugh... but...

Australia govt/navy wants to buy some new submarines. 

So they commission some to be built from an existing nuclear design... but no nukes, they’ll be repowered for diesel fuel. 

Huh. 
 

———————

 

the other thing to watch out between lipo vs Ni operation is weight balance. 200g vs 300g makes a huge difference on a 1500g RC. 

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On 5/17/2022 at 6:40 PM, Misterp180 said:

I have been looking at the Team Associated and Schumacher race buggies but don’t want to commit and then find I have no choice but to go LiPo.

They've been designed around lipo, ( and modern LiHv ), shortys, so you'll struggle to find old tech batteries that'll fit.

I'd get a decent LCD screened charger first, it'll still charge Nicad/Nimh aswell as cycle charge them (can breathe new life into duff nicad/nimh, having a controlled discharge and charge), so may get better performance out of the cars you have running nimh now,  but will also balance / storage charge lipo and High voltage LiHv lipos too, come the time you want to take the plunge.

Shorty batteries don't use deans or tamiya plugs, they use bullets, lipo are usually 4mm and liHv (high voltage lipo) are usually 5mm. I've fitted stepped plugs to mine race cars atm, so I can use either ones I have (8 lipo and 2 liHv shortys) 

 

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4 minutes ago, Wooders28 said:

Shorty batteries don't use deans or tamiya plugs

My shorty does not come with any plugs, just bare wire ends and I have to solder what I want (Dean atm, may change to XT60 in the future) on. Depends on the brand I think. 

0OjHyeC.jpg

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5 hours ago, alvinlwh said:

My shorty does not come with any plugs, just bare wire ends and I have to solder what I want (Dean atm, may change to XT60 in the future) on. Depends on the brand I think. 

0OjHyeC.jpg

These are the stepped plugs I use, and I cut the esc wires, so to reduce the chance of plugging them in wrong. (Although, you'd need to solder new leads on, as too short, I'm guessing way down on your priority list....🙄😜

 

https://www.modelsport.co.uk/product/core-rc-4mm-5mm-stepped-plug-2-405509 

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Some great advice by everyone 🙌🏻 
 

@Wooders28 like your idea of that charger that can also work with the NIHM 😎 I will take a look at Overlanders and see if they have something suitable.

 

 

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1 hour ago, Misterp180 said:

I will take a look at Overlanders and see if they have something suitable

Skyrc and Overlander look to offer the same chargers (named the same too!?! 🤷‍♂️) but skyrc look to be slightly cheaper.

I'd go for something like this, 240v (mains) supply or 12v for when out in the field, charge upto 8amp (8000mah battery) and discharge at 2amp (most are 1 amp) , with options for charge leads.

https://www.modelsport.co.uk/product/skyrc-e680-ac-dc-80w-charger-440716 

If you have bullet plugs running a shorty, these charge leads work well, allow you to fit the battery inside a charge bag with no problems. (Or you can use an adapter like alvin has done)

https://www.modelsport.co.uk/product/monkey-king-rc-charge-lead-xh2s-balance-port-to-4mm-and-5mm-black-1--431657

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12 hours ago, Wooders28 said:

These are the stepped plugs I use, and I cut the esc wires, so to reduce the chance of plugging them in wrong. (Although, you'd need to solder new leads on, as too short, I'm guessing way down on your priority list....🙄😜

 

https://www.modelsport.co.uk/product/core-rc-4mm-5mm-stepped-plug-2-405509 

Hang on, you mean the battery end (as in going into the battery) not the ESC end? I suppose one can just solder those plugs on the ESC and plug directly into the battery. 

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4 hours ago, Wooders28 said:

12v for when out in the field

For "out in the field", a suggestion will be either the ISDT (NiMHs and lipo) or ToolkitRC (lipo only) USB-C one. It can be charged off powerbanks or car ciggy charger that have at least USB QC, if PD will allow faster charging speed. 

https://a.aliexpress.com/_uA6ipd

https://a.aliexpress.com/_vD2sXv

 

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57 minutes ago, alvinlwh said:

I suppose one can just solder those plugs on the ESC and plug directly into the battery. 

Yep, that's what I mean.

(Can't find any pics of current race cars, but this is my old K1, running saddles, but the same 4mm plugs as lipo shorty, cut so the black won't reach the positive side)

2020-02-09_11-12-51

 

52 minutes ago, alvinlwh said:

For "out in the field", a suggestion will be either the ISDT (NiMHs and lipo) or ToolkitRC (lipo only)

Although cheap, it's not something I'd feel confident using, even though they maybe perfectly fine.

I'll only purchase, or recommend to others ,a UK recognised supplier (Grey area?) as per BRCA rule :must be obtained from a recognised supplier to the UK RC industry ,

(specifically charge sacks, with the theory you're getting good quality equipment). Even if you're not racing, lipo risks are lipo risks.

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25 minutes ago, Wooders28 said:

 must be obtained from a recognised supplier to the UK RC industry

Oh? No ebay, Amazon or HobbyKing then? Or even flying to Japan and buying stuff there? 

26 minutes ago, Wooders28 said:

Although cheap, it's not something I'd feel confident using, even though they maybe perfectly fine.

I got them not for the cheapness but for the convenience. I have tons of USB C QC/PD chargers for "useless" things like phone and laptops so do not want another wall wart taking up a socket. And of course the ease of charging on the move (car) or in the field (Powerbank). But then I don't race so am not restricted to where I buy my stuff. 

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5 hours ago, alvinlwh said:

No ebay, Amazon or HobbyKing then? Or even flying to Japan and buying stuff there?

Defo not eBay , there's so much fake rubbish on that place, and I'm guessing one of the reasons for the ruling, eg, amount of fake Imax B6 chargers is unreal, and if it's a cheap lipo charge bag, that may aswell be a paper bag, the only way you'd know it was fake, would be when you saw the flames..

Not sure about Amazon, guess it depends which outlet you actually deal with?, but think Hobbyking would be classed as a 'recognised supplier' (the saddles in the K1 are from Hobbyking). Buying out of Japan, I'm guessing off a street vendor, no, proper licenced outlet, you'd maybe have a valid case to be okay to use imo (if whats bought is on the legal list, uk outlets usually only stock legal stuff)

There's also the, helping support the UK RC model industry, plus if you have issues, it's easier to rectify. On the rare occasion I've had an issue with parts from Modelsport (one glitchy servo in over 30yrs) , it was sorted within the week.

 

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