RC car batteries - LiPo v Li ion, chargers

lumen aeternum

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Looking at the sales sites for radio controlled cars. The advertising copy seems to be unclear as to whether a car uses LiPo or lithium ion batteries. I bought a car whose battery says 850ma 7.4V Li-ion. The cells are about 5cm long. Its USB charger says it outputs 7.4v, 1000mA and has a rather fat plug with a circuit board & status lights. I know these toys commonly have 2 batteries in series, wrapped side by side.

Does the term "balance charger" relate only to LiPo cells, or might the Asian language barrier use the phrase for a familiar Li ion charger? The units I see illustrated are always a little box, not like the glorified USB cord than came with my unit.

My car has a battery compartment that will fit a longer battery pack (~10cm) , so I'm trying to select the right chemistry using a higher mAh.
 

lumen aeternum

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I know that there are various connectors for the battery to motor controller; what I read indicates they are rated for various amps max current draw. But I wonder if LiPo and Li ion generally have different connectors?
 

sbj

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Does the term "balance charger" relate only to LiPo cells, or might the Asian language barrier use the phrase for a familiar Li ion charger?


If a charger is labeled as "LiPo Balance Charger", it can also charge and balance LiIo cells. You can even use the LiPo Balance program directly for this if you want to fully charge the LiIo cells.

If you use the LiIo Balance program instead, the end-of-charge voltage is only set to 4.10V/cell ex works. You can spare the cells a bit.
 

turbodog

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Pack could have balance board integrated into the pack... this would be rare due to cost incurred.

To save costs... they certainly could just charge to 4.1 volts and have a low voltage cutoff in the car's electronic speed controller.
 

orbital

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If it has a white rectangular lead coming off the battery, that's the balance board.
If so, maybe get an inexpensive LiPo balance charger.

Like most LiPo chargers, you have to select 'Balance Mode' ,,, you'll learn it
You may need to make or buy some banana~specific connector you have .
(sounds like alot, it's not to hard to figure out)

 

vicv

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Lipo and lithium ion are the same thing. I mean the lipo has a polymer based electrolyte but they function the same. Charge the same. Share the same basic chemistry.
As far as balance charging, if more than one cell is in series, they need regular balancing. Either chemistry. It makes all the cells charge to the same voltage
 

DIWdiver

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AFAIK, cylindrical cells are either LiIon or LiFe, while soft-sided pouch cells are LiPo. If you have something else, then all bets are off.

As vicv says, LiIon and LiPo are theoretically interchangeable. However, the issue is often that one doesn't physically fit very well in an application designed for the other.
 

lumen aeternum

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This is the battery type. Bonzai 850mAh

2 rechargable Li-ion 15C 850mAh batteries and a quick balance USB charger.
>
I previously found the battery listed alone for sale, but I can't find the listing anymore.
EDIT - found it:

& Q&A says its two Li Ion in a wrapper.

But the car has space for a longer battery, so I need the knowledge to figure out for sure if its LiPo or Li Ion.
If it has a white rectangular lead coming off the battery, that's the balance board.
yes it does. And that's what plugs into the USB charger that came with it.

I also see that there are several types of power connectors on RC car batteries (battery to controller) and I'm not sure if its purely for amperage, or by convention/safety design it differs between battery chemistry.
 
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turbodog

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This is the battery type. Bonzai 850mAh

2 rechargable Li-ion 15C 850mAh batteries and a quick balance USB charger.
>
I previously found the battery listed alone for sale, but I can't find the listing anymore.
EDIT - found it:

& Q&A says its two Li Ion in a wrapper.

But the car has space for a longer battery, so I need the knowledge to figure out for sure if its LiPo or Li Ion.

yes it does. And that's what plugs into the USB charger that came with it.

I also see that there are several types of power connectors on RC car batteries (battery to controller) and I'm not sure if its purely for amperage, or by convention/safety design it differs between battery chemistry.

Ok... now we've got something to work with.

It's moot as far as battery chemistry goes. BOTH require a balance lead for the charger. Any decent charger w/ charge either.

If the pack (under the wrapper) feels square w/ sharp-ish corners then 99.9% you've got a lipo, especially if you can't feel the cylindrical cells a 2 cell pack would have. And FWIW, I've not seen li-ion in r/c equipment at this price point, nor any price point.

The connectors are part amperage spec'd and COST spec'd. They can be replaced w/ something a better charger w/ interface with... assuming the balance lead is a standard type. There are numerous balance lead types... and most chargers w/ come with a variety of adapters. An adapter could also be made/bought so that you can fast-charge w/ a good charger w/o having to replace the battery ends.

I really question the specs on that charger... usb only supplies around 2.5watts (usb2) and 4.5watts (usb3).

If you're going to stay in r/c... a decent/proper charger w/ greatly increase your fun. You can charge packs much faster (but still safely). Your local hobbyshop and r/c club will be a good place to find a used charger for cheap, or amazon.

This is coming from 35+ years of r/c: cars, trucks, heli, boat, quadcopter using nicd, nimh, lipo, and nitro.
 

lumen aeternum

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OK, the pack size is about 20mm thick x 50mm long x 34mm wide for the pair of cells, so I guess its made of 14500 cells.
Now the battery tray in the car frame seems to be 103mm long, but the soldered connections add about 8mm of length... Or buy higher capacity cells.
 

vicv

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It’s probably not made of 14500 cells. It’s a pouch cell. Basically an aluminum foil bag filled with cell material. No metal tube. But you’re over complicating this. Any lithium 7.4V battery will work if it fits and the c rating is high enough. If it would fit, a 6s 7.2v nimh battery would work, but would need an appropriate charger
 
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orbital

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If you want your car to really rock, get actual 3S Lipo batteries that'll fit your chassis,,
and use a dedicated LiPo charger like the one I mentioned above. You'll love it.

Just need to solder on the xt30 connector to your esc.


I'v done alot of 6S truggy running at some local tracks,, it started w/ 2S and went from there.....
got the series Lipos'/motor/gearing for an 8S setup in my 6S truggy, it will trench!

=My first rc was a Tamiya Rough Rider, built it in my parents basement in the late 70s'
the bodies came clear, you had to paint.
 
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lumen aeternum

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I've not seen li-ion in r/c equipment at this price point, nor any price point.
I bought that car because of the Li-ion battery system, I'm familiar with it from my flashlights and LiPo seems to have more safety concerns when charging. Also Li-ion can be left on the shelf without degrading for a lot longer.

if you want your car to really rock, get actual 3S Lipo batteries that'll fit your chassis

The car is 1/14 scale. Seemed a good price at 20% off - 2 batteries, carbon fiber parts:

The battery tray is just wide enough for the 2x1 OEM pack, about 35mm x 103mm, with a foam spacer. So a 2x2 pack would be too long ! Unless I can tilt it a bit & find a way to secure it. Or create my own 3S with the 3rd fitted diagonally.

I wish the controller had a second trim pot to control the RATE of steering response. I see some controllers being sold with a matching receiving unit. Dunno how the controller & car pair themselves. I see that the receivers are rated for max Amps. So not sure how to find a compatible controller with the RATE feature.

Will the slightly higher voltage (7.4v) of a LiPo do any damage or extra heat to the circuitry?

My neighbor got a cheapo 1/18 car for his 6 year old, and we started playing with it more than the kid, so I got one of my own.
***
I'd like to get a tank that shoots airsoft pellets.
Exbonzai 1/16 M3 Lee:

I'm looking for a good RC car forum. I found a couple, but not much info for newbies - discussion of differences between brands, what parts are generic and what brands use proprietary parts. etc. Seems like the "serious" hobbyists use the larger scales - 1/10 and bigger? The 1/18 and smaller seem be be just toys & not modified.

 

vicv

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There is no chemistry difference between lithium ion and lipo. Lipo is not more dangerous to charge. It's because people charge them at very high c rates and they are buying cheap low quality batteries. They do not self discharge anymore. Your cell phone has a lipo battery in it. So does your laptop more than likely
 

orbital

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.. Your cell phone has a lipo battery in it. So does your laptop more than likely

+

- Including the better emergency car battery jumpers
- powerbanks
- recall reading some EV manufactures using Lithium Polymer



LiPo batteries give amazing performance because of the HUGE Amps they can sustain
..those Amps equate to performance in everything.

I use mine for other things than rc,, just yesterday before I posted, I charged up two 5S units and two 6S units.
 
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lumen aeternum

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So would need to find a 7.4v Lipo that fits into a 35x100 space. And significantly more juice than the stock 850mAh.
I've seen the connectors for sale, and some X to Y connector couplings.

Too bad the tray is not wide enough for two 18650 side by side.
Anyone make 3S using 14500 in a pyramid? If I could only solder stuff...
Are Li-ion packs for RC made with or without the over-discharge cutout circuit?
 

turbodog

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So would need to find a 7.4v Lipo that fits into a 35x100 space. And significantly more juice than the stock 850mAh.
I've seen the connectors for sale, and some X to Y connector couplings.

Too bad the tray is not wide enough for two 18650 side by side.
Anyone make 3S using 14500 in a pyramid? If I could only solder stuff...
Are Li-ion packs for RC made with or without the over-discharge cutout circuit?

Without. Your electronic speed control makes a good guess and the number of cells present (usually beeps to count cells). It will shutdown before the overall voltage drops too low.

There exists a device for the balance lead that monitor individual cell and overall volts. Sounds a LOUD alarm to indicate too low values. I use mine for flying.


1652317504145.png
 

vicv

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So would need to find a 7.4v Lipo that fits into a 35x100 space. And significantly more juice than the stock 850mAh.
I've seen the connectors for sale, and some X to Y connector couplings.

Too bad the tray is not wide enough for two 18650 side by side.
Anyone make 3S using 14500 in a pyramid? If I could only solder stuff...
Are Li-ion packs for RC made with or without the over-discharge cutout circuit?
Well 3s 14500 would only be about 600mah and take up more space. Don’t think it would be an advantage in any way.
I’m a bit confused. What are you trying to accomplish? Lithium ion imr type cylindrical cells will give you no advantage whatsoever. Because of packaging, you will lose capacity and current capability.
 

turbodog

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Well 3s 14500 would only be about 600mah and take up more space. Don’t think it would be an advantage in any way.
I’m a bit confused. What are you trying to accomplish? Lithium ion imr type cylindrical cells will give you no advantage whatsoever. Because of packaging, you will lose capacity and current capability.

In addition, assuming the wiring, ESC, motor, transmission, tires, etc can handle the LARGE increase in power... that's a brushed motor. You're gonna eat it up, and I doubt the brushes are replaceable.

Take the car, run it, enjoy it, wear it out. If you had fun... find a low end hobby-grade vehicle to step up to... one which has spare parts, clearer battery options, replaceable tires, and a brushless motor.
 

orbital

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... find a low end hobby-grade vehicle to step up to... one which has spare parts, clearer battery options, replaceable tires, and a brushless motor.
+

^^^^^^^^^ this

especially the spare parts, part of it.
Must have the ability to get replacement parts.
________________________________________________________________________
As a hobby, you are repairing, modifying, replacing parts alot. It's literally the 'hobby' part of it.
My modifications, customization's are mainly for it stay together = if possible;)


have fun
 

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