Battery Upgrade for 24v Grave Digger Power Wheels

Intro: Battery Upgrade for 24v Grave Digger Power Wheels

Today I'm upgrading the battery capacity on my 24v Grave Digger Power Wheels. The stock batteries are a pair of 12v 7.2Ah batteries run in series, for a total of 24v 7.2Ah. The stock 7.2Ah batteries were already lacking with the stock motors and I exacerbate that lack when I upgraded to faster Traxxas motors.

This article will detail how I upgraded to 20Ah capacity (nearly triple the run time of stock batteries). While I was in there, I added a charging port because having to remove the seat screws to charge the battery got annoying quick.

Materials Needed:

2x 12v 20Ah SLA Batteries (batteries between 18-22Ah share a case size, so you can use most SLA batteries between 18-22Ah. 22Ah would be even better, but I already had one 20Ah battery so I just purchased one more)

10awg Fuse Holder - this 10 pack is a great value, plus you should be using these on all your modded rides, so get extras!

Charging port

24v 2A XLR Charger - Twice the charge rate of the stock charger, while still being safe for the new batteries.

Various Crimp Fittings / Scrap wire / Shrink tubing

Tools Needed:

Crimper

Strippers

Drill w/ 1" bit

Screwdrivers

Multi tool with metal/plastic blade

Multimeter

STEP 1: Trim Out the Stock Battery Pan

The stock battery sat on a little platform of raised plastic ridges. All that crap has to go to make room for the much larger 20Ah batteries.

I found the easiest way was to cut straight down at each intersection with the multi tool, then score lightly along where it meets the bottom of the body. Then grab the pieces with a pair of pliers and twist it off in chunks. Keep test fitting your batteries and removing more material until the batteries sit flat on the bottom of the compartment.

If they made the bump outs just a hair smaller, the batteries would fit like a glove... but they didn't make this easy on us, so the batteries end up sitting in there slightly crooked. Hurts my OCD, but its under the seat and no one will see.

The seat also has some structural honeycomb cardboard on it that used to sit on the shorter stock batteries. I used the multitool to trim that down as well. Cutting it about in half fit on top of the new batteries very nicely.

STEP 2: Wire Up the Fuse Holder

The fuse holder is one of the most important aspects of any modified power wheels build. DO NOT SKIP THE FUSE HOLDER. I'm wiring these batteries in series, so I used my 10awg fuse holder to connect the pos/neg terminals together. When I connect the vehicle wiring to the other terminals, this will create a 24v 20Ah battery cell.

If you're running stock motors, stick with the 30a fuse. If you've upgraded, you might need to run 40a fuses. If you up the fuse size, YOU NEED TO MONITOR TEMPERATURE OF MOTORS AND WIRING. If the wires and motors are getting too hot too touch, you are overloading your circuits and asking for melted wires, fires and hurt kiddos. Every riding circumstance is different, so if you're unsure of what you need to be aware of, don't modify your kid's ride on toys.

STEP 3: Test the Charger and Wire Up the Charging Port

You need to find out which prong on the charger plug is positive and which is negative. Do this by touching the prongs with your multimeter (set to 20v dc). It should read +24v when you have the red on the pos and the black on the neg. It will read -24v if you have the leads reversed. Once you know which prong does what, label the side of the plug with +/- in sharpie.

Now compare the prongs on the charger with the socket on the charging port. Solder 12-14awg wires to the terminals on the back that correspond with the pos/neg prongs on the charger. You'll soon be attaching these wires to the battery, so make sure your polarity is correct.

I soldered my wires to the XLR receptacle and used heat shrink tubes to cover the connections. I just used scrap 14awg wire that I had laying around, although this port accepts up to 12awg wire.

STEP 4: Mount the Charging Port and Wire the Battery

To mount the charging port, I simply drilled a 1" hole in plastic between the foot well and the under-seat battery compartment. I fished the soldered wires through the hole and screwed the receptacle to the wall. This will be where I plug the charger in.

Once I had the charging port wires into the battery compartment, I just cut them to length and crimped ring terminals on. I also cut the stock battery plug off the wiring harness and crimped ring terminals onto those 10awg wires. Then I connected the ring terminals to the screw terminals on the new batteries.

STEP 5: Go Play!

That's it! Now you're ready to enjoy longer run times and easier charging on your 24v Grave Digger!

If you've enjoyed this mod, please take a look at my other Instructables. I have detailed write ups on improving the shocks, turning radius and speed on these new Grave Diggers.

I'll be posting the rest of my mods here as I continue to upgrade our GD, so follow me on here to see the latest mods!

Comments

[Rtholthaus]

Could anyone please help me with an updated link to a charger and charge port I need to charge the 22ah batteries? Thanks!!

[MacGyver Dad]

Wanted to give it a few charge cycles before posting but I'm here to give this mod instruction TWO THUMBS UP! Did this mod on our used Grave Digger and couldn't be happier. Used the 22AH batteries and this bad boy rides non-stop for AT LEAST 90min. Going up hills through our backyard in the Smokey Mountains and just keeps going. Highly recommend this swap to others. Also, the charge port is really nice and battery charges in roughly 5-6hrs from a nearly complete drain using the recommended charger.

[richiecollins5309]

Someone please help I have the roll around monster truck it has an 11 pin control circuit board in the back with a high speed lockout button I need to replace that control board no one has it in stock I can't find it anywhere what am I going to do

[richiecollins5309]

This is the board that I need to replace I forgot to post pictures of it earlier! It's for a 24-volt ride along monster truck. Is there anything else that's built on the same platform where I can find parts for it that would match. I'm willing to do all any of the work myself I just need a little help finding it. I got this for my son and he's not ever been able to ride it it was broken after we bought it by someone else He's looked at it every day but never been able to get on it and do anything.

[Stboyd91]

Can I do this upgrade to with the stock motors ? The battery burned up and I thought this might be better than buying a stock replacement

[uke629]

How do you get the rear tires off? I used a 1/2" socket and it just kept spinning. Seems like I need the lock up the motor to get the axel nut off. Any suggestions? Thanks.

[PoppaFixIt]

You need a wrench on both ends to hold back and keep it from spinning. You might need a second person to help hold it if you can't quite reach, it's tricky for me and I have really long arms.

[andrewh472]

Thanks for the excellent write up. I want to know if I can use the stock batteries with the charger and port you mentioned. I imagine the process is a bit different?

[Triguy74]

Followed your guide every step of the way. My kids love the longer ride time and my wife loves that she can plug it in to charge now without taking the seat off.

Thanks for taking the time to post this up! Going to tackle the turning radius project next I think. 👍🏻

[mrcoachslack]

I have changed the batteries(2 -12v 22ah), fuse holder, circuit break using all the suggested parts but it blows fuses. I can change the 40a fuse and the sounds work but when the pedal is pushed the fuse immediately blows. Any suggestions of what is causing the problem.

[Bodi2015]

I cannot get the batteries to charge. I bought the batteries as shown but I used the plug from the original batteries. I have used the charger that came with the car. I did buy the charger that was recommended but I can’t solder so I went the easy route. I also tried using a different trickle charger.

[PoppaFixIt]

It might be easier to charge each battery individually with a 12v charger. I had been using a 2-bank smart charger to charge each one separately and it worked well.

[campbellw]

you might want to add a cover to the charging port, to protect it from wet weather/snow/mud.

[JoelD101]

Awesome post! I read through it and had success! Thank you for all your info. It felt like having a friend/neighbor with me when I was working through it. Thanx PoppaFixIt!

[Amardeep Gillg]

its very helpfull sir.so thanks for help.now i can easliy upgrade my kids car.