ghetto mod toy car battery?

Soldato
Joined
3 May 2012
Posts
5,390
So my nearly 3 year old son got a remote control car off a neighbour, its a.. well one of these:

https://www.amazon.co.uk/Nikko-1994...19&hvtargid=pla-385264639823&psc=1&th=1&psc=1

It uses a 6v 700mah battery, a little like this although this one isnt an exact match:

https://images-na.ssl-images-amazon.com/images/I/51E5QVcr2tL._AC_.jpg

**Do Not Hotlink Images **

The battery though is knackered, doesnt hold charge for very long at all, its also pretty rubbish in terms of capacity even at full health, the one in his car is 700mah as new.

I took 4 AA batteries and held tham up against this, and note they would easily fit, I am wondering, if I opened the thing up, if I would find just a set of AA batteries in there? Anyone tried it?

I have 2000 mah 1.5v AA batteries right here, they are 1.2v, but if I put them 4 of them in serial thats 4.8v and 8000mah! Infact looking at the size of the box, it'd probably fit 5 of those AA batteries which would then match the voltage and give a whopping 10,000 mah.

I mean one of the instructions on the battey itself states: Do not dissamble or remodel the Ni-Mh - surely that is a challenge?

And I did just look on ebay fpor a replacement or like for like copy, official Nikkon battery was like £30 - no thanks, and the only other 6v batteries I could see where lead acid for like small motorcycles, infact I am sure my first motorcycle had a 6v battery.
 
Last edited by a moderator:
Soldato
Joined
24 Oct 2012
Posts
22,382
Location
London
Your sig makes me wonder why you're here asking us and not McGuyvering already!


You might be able to squeeze a few 18650s in there too so your boy can play non-stop all the way past puberty, two birds, one stone :D



EDIT:

Badass :cool:

 
Last edited:
Soldato
Joined
30 Jul 2005
Posts
17,374
Location
Midlands
iv done many battery mods on these sort of toys, these days i slap in some 18650 protected cells and watch the mayhem. lithium ions high instantaneous current delivery along with very low voltage drop means instant wheelies and burnouts. hahha.
 
Soldato
OP
Joined
3 May 2012
Posts
5,390
Id never heard of 18650 batteries, they are 3.7v so 6.4v in serial, reckon that'd be ok.

Do you need a specific charger for them?

Edit: Damnit 7.4v I can't add up!

Reckon 7.4v would kill it?
 
Soldato
Joined
24 Oct 2012
Posts
22,382
Location
London
Well, if it did, you could always stick a brushless motor in it so it could go on land, water and probably fly too :cool:
 
Soldato
Joined
30 Jul 2005
Posts
17,374
Location
Midlands
tricky bit here, since 2 full charged cells will actually be 4.2v each cell so 8.4v fully charged. the motor will handle it but on one cheapo car iv fried the wireless part.
 
Soldato
OP
Joined
3 May 2012
Posts
5,390
Ok first things, my clear lack of electronics, of course, batteries in serial only multiply the voltage not capacity, doh!

So I opened it up, it is literally 5 AA batteries in serial with metal plates over the poles and a insulation pad to stop it shorting.

Should be easy to directly replace with new NiMH batteries.

EDIT, even better, found a pre-made 6v battery pack (which is literally still 5 AA batteries) but 2500mah capacity and thats done the majority of the wiring for me, plus it was cheaper anyway as you cant really buy 5 AA batteries without having to buy 2 packs of 4.
 
Last edited:
Soldato
Joined
27 Mar 2013
Posts
7,454
Ok first things, my clear lack of electronics, of course, batteries in serial only multiply the voltage not capacity, doh!

So I opened it up, it is literally 5 AA batteries in serial with metal plates over the poles and a insulation pad to stop it shorting.

Should be easy to directly replace with new NiMH batteries.

EDIT, even better, found a pre-made 6v battery pack (which is literally still 5 AA batteries) but 2500mah capacity and thats done the majority of the wiring for me, plus it was cheaper anyway as you cant really buy 5 AA batteries without having to buy 2 packs of 4.
Makes you wonder how they got such a low capacity to start with, I've not seen any AA rechargeable batteries that are less than 1000mah capacity.
 
Soldato
OP
Joined
3 May 2012
Posts
5,390
Makes you wonder how they got such a low capacity to start with, I've not seen any AA rechargeable batteries that are less than 1000mah capacity.

Cheap batteries.

I don't even know why they do it because I couldn't easily find a replacement for sale, so would indicate they are not trying to sell additional batteries.

Unless they just don't want the toys lasting too long so you have to buy new ones maybe, I don't know.....
 
Man of Honour
Joined
13 Oct 2006
Posts
83,150
Id never heard of 18650 batteries, they are 3.7v so 6.4v in serial, reckon that'd be ok.

Do you need a specific charger for them?

Edit: Damnit 7.4v I can't add up!

Reckon 7.4v would kill it?

Yes li-ion needs a special charging approach - for a single li-ion battery you can use a cheapy tp4056 based board but for multiple batteries you need something really designed for the job - if you have all new batteries you can get away with charging them in parallel from one board but if one of the batteries changes properties substantially things can go badly wrong.

Though li-ion/li-pos etc. are regularly used in remote control vehicles, etc. I'm not a fan as they aren't exactly good at handling kinetic impacts and can potentially catch fire. NiMH is far simpler and safer.

If you do go that route there are loads of options for voltage regulators that can provide the right voltage output through buck/boost operation but you'd need to match the current requirements.
 
Last edited:
Soldato
OP
Joined
3 May 2012
Posts
5,390
Yes li-ion needs a special charging approach - for a single li-ion battery you can use a cheapy tp4056 based board but for multiple batteries you need something really designed for the job - if you have all new batteries you can get away with charging them in parallel from one board but if one of the batteries changing properties substantially things can go badly wrong.

Though li-ion/li-pos etc. are regularly used in remote control vehicles, etc. I'm not a fan as they aren't exactly good at handling kinetic impacts and can potentially catch fire. NiMH is far simpler and safer.

If you do go that route there are loads of options for voltage regulators that can provide the right voltage output through buck/boost operation but you'd need to match the current requirements.

I'm just at going to replace it like for like 6v NiMH all be it higher capacity. But thanks for that post it's interesting definitely learning stuff.
 
Soldato
Joined
18 Oct 2002
Posts
5,220
Location
Overground, underground..
Makes you wonder how they got such a low capacity to start with, I've not seen any AA rechargeable batteries that are less than 1000mah capacity.

I've taken apart a few things that had low capacity ni-cd/ni-mh AA cells.
I've never taken the cells apart, but it's possible they're AAA cells in sleeves.
 
Soldato
Joined
19 Jan 2006
Posts
4,251
I have 2000 mah 1.5v AA batteries right here, they are 1.2v, but if I put them 4 of them in serial thats 4.8v and 8000mah! Infact looking at the size of the box, it'd probably fit 5 of those AA batteries which would then match the voltage and give a whopping 10,000 mah.

I hate to break it to you....

Edit: Oh you've noticed already :D
 
Soldato
OP
Joined
3 May 2012
Posts
5,390
Oh yeaa!!!!!!!!!!!!!!!!!!!

So battery pack arived, soldering part was easy but jamming the thing back into that plastic case took some effort as new battery pack was just ever so slightly wider plus with the extra wires, it did require cutting sections of the plastic out, quite forcefully jamming it all in, and some parcel tape applied very tightly to strap it up, but I have to say the thing is fatastic now, weve been driving out in the garden for 10 times as long over the grass everything, it still hasnt run out, its been turned off now for another day.
 
Commissario
Joined
17 Oct 2002
Posts
31,127
Location
Panting like a fiend
I've taken apart a few things that had low capacity ni-cd/ni-mh AA cells.
I've never taken the cells apart, but it's possible they're AAA cells in sleeves.
IIRC early/old nicad AA's often had capacities of around 700ma and cheap "battery packs" for models didn't change much due to the very low cost.

Later better made ones went up a bit, but it wasn't until you got to NiMh that you started to get IIRC 1500ma as the starting capacity, 1800-2100 as the norm, and 2500-2800 as a common "high capacity" ones. Many kids toys and things like cordless phones up until about 10 years ago still seemed to use nicads by default as the battery packs and charging circuits were dirt cheap by that point (partly because nimh and lithium had started to take over at the mid to higher end of the range and the nicad production lines had long since paid for themselves).

I may have been using them for a very long time:p
 
Soldato
OP
Joined
3 May 2012
Posts
5,390
OK.

After the sucess of the first battery mod, I am wanting to give this another go. I also have an older RC car, that I bought for my now (nearly) 14 year old, when he was....I dunno, 6 or 7 maybe.

They run on a similar battery pack, but this time 7.2v nimh, the battery pack is very similar so pretty sure it'll just be the same as the last one all be it 6 cells (basically 6 AA batteries) in a row rather than 5, 1.2v x 6 = 7.2v which is the battery packs rated voltage, the stated capacity is 1000mah, but again, these batteries are OLD, so I doubt they are even that.

However, this time, rather than getting a like for like nimh battery pack and getto modding it into the existing plastic case I think I will try those 18650 batteries on go lithium. Those are 3.7v, so if I use 2, thats 7.4v which I will risk. What I might try is, get a 2 cell holder wired in parralel like this :

https://www.ebay.co.uk/itm/18650-Ba...475059?hash=item2a9f506ef3:g:LOoAAOSwkDtcWf8~

And then buy 2 18650 batteries and a charger. I know they wont charge from the toys own charger, I am not even going to attempt that. So my plan is, take the plastic battery case apart, take the existing nimh cells out, hot glue that 18650 battery holder as linked above inside length ways, solder the ends of the wires to the inside of the contact points in the plastic case so it still fits in the car. Probably just need to cut a whole in the top of the plastic case so I can get the batteries in and out, I know it'll sit a bit proud in the existing plastic case, but I think it'll be ok.

Edit: battery pack wired in serial*
 
Last edited:
Associate
Joined
20 May 2003
Posts
861
Location
Nottinghamshire
I have 2000 mah 1.5v AA batteries right here, they are 1.2v, but if I put them 4 of them in serial thats 4.8v and 8000mah! Infact looking at the size of the box, it'd probably fit 5 of those AA batteries which would then match the voltage and give a whopping 10,000 mah.
When you connect batteries in series, the mAh rating stays the same, but the voltage increases (so 4x 1.2v 2000mAh cells = 4.8v 2000mAh battery). When connected in parallel, the voltage stays they same, but the mAh is added together (so giving a 1.2v 8000mAh battery)

BTW, when looking for 18650 cells, it's probably best to buy them from somewhere at least semi-reputable, as there are loads of "fakes" out there; or more charitably perhaps cells that have very optimistic capacity ratings (anything advertised with much greater than 3500mAh is likely dodgy, and a fraction of that in reality).
Also as other have mentioned, in this application, it'd be a good idea to get "protected" cells, as the toy won't have any inbuilt battery protection (and be aware that the protected cells are typically slightly taller than the unprotected ones, so can be a tight fit in battery packs).
 
Caporegime
Joined
22 Nov 2005
Posts
42,740
Location
Newcastle Upon Tyne
Though li-ion/li-pos etc. are regularly used in remote control vehicles, etc. I'm not a fan as they aren't exactly good at handling kinetic impacts and can potentially catch fire. NiMH is far simpler and safer.
they are dangerous if mishandled/stored.

you can buy bags to put them in for really cheap though for safety when storing them
 
Top Bottom