Introduction: How to Upgrade the Battery-life of Your RC Vehicle?

Picture of How to Upgrade the Battery-life of Your RC Vehicle?

This post will discuss how you can upgrade the battery/battery-life of your RC car to increase the running time of the car.

http://www.slideshare.net/pranavrathi/how-to-upgrade-the-battery-life-of-your-rc-vehicle

This thanksgiving I bought a 6.4-Volt Ford Raptor truck from Walmart for $15 (on sale) for my 3 year old son, who loves to chase RC cars. In the beginning I was very happy with its performance and speed. But Soon I realized that it had such a short life time of 15 to 20 minutes, which was very disappointing for my son.

Step 1: Original Battery

Picture of Original Battery

So I thought may be something was wrong with the battery because this was such a big truck (1:15). I opened the truck and this is what I found out (image 4). The blue thing in the image 4 was the battery powering this truck- a 6.4V 350mAh rechargeable battery. So it explained the short life time

Step 2: Look for the Additional/replaement Battery

Picture of Look for the Additional/replaement Battery

I decided to increase the lifetime by adding a bigger battery to it. I searched online and found a suitable addition on batteryspace.com. I bought a 6.4V 1600mAh rechargeable battery for $30 (shipping included). It was a LiFePO4 battery which offered great cycle life, constant discharge voltage and great safety (safety was important because it was to be incorporated in a toy).

Step 3: Adding the Batteries Together

Picture of Adding the Batteries Together

The idea here was to increase the lifetime/working time of the vehicle by increasing the capacity of the original battery. And it was done by attaching the two batteries (original (blue) with new (white) in Parallel, so the voltage remained same of 6.4V but the capacity was increased from 350mAh to 1950mAh (350+1600). If you want to increase also the performance- you have to increase the output voltage, which is very risky because the circuit was designed for a certain voltage. So never put the batteries in Series if you are not sure.

Once the batteries were solded together I mounted the blue battery in its holder and white battery (which was little heavy) above the rear wheels (it was a real wheel drive truck) to give it more stability. Now the truck was ready with roughly 5 time increase in working time (roughly 100 to 120 minutes). My son was really happy with this upgrade and I was too because now I could make him sweat.

Step 4: Conclusion

Picture of Conclusion

The charging time was also 5 times longer now- (because

there was no chrger provided with the truck) I use a 5 Volt 1A cell phone charger to chare the batteries. It took almost 6 to 8 hours to fully charge the batteries.

The procedure is outline in the pictures. It will be different depending on the vehicle but the idea would be the same. Please be safe when playing with the batteries.

Comments

Gomi no Sensei (author)2016-02-04

I hate it when people without the first idea about electricity make Instructables with lithium ion batteries.

This is TOTALLY UNSAFE, lithium ion batteries need to be charged at 4.2v with a specific cutoff charging circuit. These small circuits can be bought off eBay for less than $1.

Follow this persons instructions if you want to burn your house down. Or jump on eBay, spend $1 and save yourself the heartache.

The truck already have the cutoff circuit to prvent from over charge.

pranavrathi (author)2015-12-25

I wanted to post this comment as a review of this instructable. In in the nutshell I am very happy with it without any problems. I ran the truck for more than an hour in one sitting and i still have to find-out how long can it go before the batteries are flush out completely. I noticed one issue when batteries are low the RF range goes down but the truck runs just fine. I abused it so much over these holidays that the gears have started making noise.The batteries are safe- do not even get warm during charging. I know people are concerned about safety but I never felt any such issue- theses are just a low amp output batteries not an RDX. One concern is that one of the batteries might have a shorter life due to imbalance but i think this issue should be researched and tested before reaching to any conclusions. I am very happy that I made this

XavierF5 (author)2015-12-21

perfectly safe to do this instructable with nimh's but you should NEVER do this with a lipo.

Mikker (author)2015-12-20

danger

monkeyracing (author)2015-12-19

Please, for the sake of safety, disconnect these batteries from one another and use a proper charger for the lifepo4 battery! You have decreased safety dramatically!

bottmanakers (author)2015-12-18

Great job. Simple and gets to the job done. As far as safety goes despite what others are saying it's completely safe and in some respects safer than it was. Due to the lower charge rate to capacity ratio, but you already know this.

ThomasK19 (author)2015-12-17

This is not a good idea. LiXX batteries need a special charge cycle. And connecing them in parallel will make one of the cells go to heaven (where worn out batteries live a battery-worth sort of life) very early. In the worst case you risk putting them on fire. Better replace the small by the bigger one and re-use the smaller somewhere else.

ThomasK19 (author)ThomasK192015-12-17

And reading on I see you even don't use a LiXX charger. In this case you dramatically decrease battery life and in the same amount increase the danger of putting them under fire. This is not very funny. I can tell you (see YouTube about exploding LiXX batteries).

pranavrathi (author)ThomasK192015-12-17

Battery might go bad or explode if the charging current is too high. The recommended charging current of this battery is around 1.2Ah at 6.4 to 7V. The charger I am using is only 5V under 1A. It is good to use smart charger with charge indicator. Truck itself has that- it turns off the charging when the batteries are full.

ThomasK19 (author)pranavrathi2015-12-18

So that's good news. But using the cells in parallel will ruin one of either. The inner resistance of the cells is different an the one with the lower resistance will take more charge and its voltage will increase faster. So you can't use the full capacity. So you should charge them disconnected from each other. Also when discharging one of both can be in danger to undercharge.

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Bio: I am an optical engineer and love to design and build things out of trash for a good use of research.
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