Milwaukee M18 Kids 12V Jeep Battery Upgrade 

Blaise, I'm pretty sure you're already a cool dad! 😄

@@DoresoomReviewsso

Glad you liked it!

does this Battery give more power than a 2ah battery or even 5 ah? I did the switch and my sons jeep with a 2ah battery isn't that quick! . Let me know what you think@@DoresoomReviews

I installed the battery adapter and voltage regulator. The power wasn’t there. I just deleted the voltage regulator. So strait 20 volts to the stock wiring and this jeep has some pep in its step. Only drove it around for about 30min. Nothing seemed to be damaged. All the electronics still work.

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

Great idea! I actually have some mountain bike tires I bought to do exactly that! 😂 I also 3D printed some TPU treads that have awesome traction, but they were a stretch fit and slip off too easily. Screws or adhesive is my next step!

Oh no! At least it's something replaceable. The buck converter should definitely help with that. Also, be sure not to drain an expensive 12Ah completely, since the low voltage protection relies on an M18 tool to stop drawing power.

Question, what size of fan are you using 12v?

Have fun! You might have to take up jogging or biking to keep up with her after the upgrade though! I used one of these 80mm computer fans: amzn.to/3FdVLL2

@@DoresoomReviews ahaha :o,, thanks!

@@DoresoomReviews hey man i need help with the enclousre, I want to print it, but the scale is really small 3mm.. what scale is the right size? z y z axis, sorry kind of new to printing world, but i notice when i hit slice 0min to print it, because is so tiny. ahah

do i just add 80mm to Y axis?

That's odd. Are you able to hook up a multimeter and get a voltage reading while it's bogging down?

I just tested it. Looks like it bogs down immediately to live with 4 volts, but slowly climbs up to 14 v (like 5 seconds). Any idea why I bogs down so much at first?

​@@clarkvargo1066 my BCP Jeep is doing this exact thing. 18v Ryobi battery hooked up same as this Video.

Did you get this figured out and does the truck have a soft start?

@@clarkvargo1066 did u figure it out .. mine too

Thanks! I bought some 12" bicycle inner tubes to stretch over the 14" diameter wheels. It seems to add a lot of traction over the bare plastic for driving on concrete. They need some adhesive though, since they fall off after about a mile. Plus I have concerns about their durability. Maybe I'll try cutting up some actual off road bike tires and epoxying them on next.

@@DoresoomReviews rubber mat (thin door mat or ute/truck tray mat) attached with a construction adhesive rather than epoxy (too hard and brittle). Silane modified polymer (SMP or MS Polymer) sticks to most things.

Yeah, I was planning on a flexible adhesive. Guess I should have clarified rather than saying "epoxy." Thanks for the suggestions!

Update : This little jeep is insane! Runs for hrs on a 5ah millwalkie at 90%.

The Jeep is still running great. No problems at all.

I have mine set up for 14V output, and it drops to about 13.75V on a steep hill using the M18 battery and buck converter. Using the original lead acid battery it was dropping to 11V on hills. The Jeep I have is a Best Choice Products model rated for 3.7 MPH by the manufacturer. Do your lead acid batteries state their max current output? 300W at 14V is over 21A coming out of the buck converter. On the battery side of things, you're looking at a minimum of 12.5A at 24V without accounting for efficiency losses. Since you have the batteries in series, then they each need to be able to put out that much since voltage adds instead of current. M18 5Ah batteries can output well over 30A easily. To hit 300W at 18V, the Milwaukee battery only needs to output 17A. I'm not saying for sure that's the problem, but I'm guessing it's the current discharge rate of the lead acid batteries that are limiting performance. Other commenters have reported low performance on different models of jeeps with this same setup though, so I can't say for sure that the M18 battery will fix the issue.

Thanks for the reply. I got it figured out…… the remote control was stuck in the low speed setting. I had no toddler in the car. I was testing it with the remote. Oops. But now it kicks butt at 14 volts. In fact , a little too fast. I think 13.5 steady volts will be fine. 👍

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

I had a friend attempt this conversion recently and he ran into similar problems. The manufacturer of the buck converter changed their design without updating the product description, and the new ones can't supply enough current. If you bought the two-pack, try wiring them in parallel between the DeWalt battery and the vehicle. That solved the problem in my friends' case.

I'd try the 20V first, just by hooking it straight up where the original battery connects to. It will probably run a little slower though. If it's too much of a loss of speed, then you could look into a 40V to 24V buck converter.

You could try a 6V battery, but it's possible that will make it too slow. For DC motors, speed is proportional to voltage.

Sorry, I don't have plans to sell any kits.

Good point - the 300W one I found didn't though.But as long as I pull the battery after my daughter is done driving, no issues so far.

Thanks for confirming. I usually swap batteries after 1-2 miles just to be safe.

Yes, I'd go with the 500W buck converter if you have 4 independent motors. Good call!

@@DoresoomReviews Thank you!

Sorry, I don't plan on selling them. Check your local library, it's possible they have a 3D printer available to use. Or you could make it out of wood or acrylic instead of 3D printing.

I designed it in inches, and your slicer imported it as millimeters. Scale it up by 2540%.

@@DoresoomReviews thank you, I figured it exactly after I posted the question :D

That's how it always works! :)

I took it off, but it's probably fine to keep it on.

There's not a way to charge the power tool batteries in place. It's pretty easy to just pop them out to charge though.

The problem is I don’t have a charger, I only have the battery, I was thinking why can’t we just use the charging port for the car itself to charge the drill battery, I mean it goes through the same motherboard and system, so I was thinking why can’t we just the regular car charger and charging port to charge it

Lithium ion battery cells need a charge controller, unlike the lead acid battery the car comes with.

The only connection to the car is power. So unhook the lead to the battery, cut the connector off (after marking positive and negative!). Then solder on new terminations that match your buck converter and connect.

Yeah, 14V is all I've done. Still working great! Unless you go through and inspect each components' design specs in the boards, it's kind of a crap shoot when applying higher voltages to it.

Don't run more than 1 battery unless you're wiring them in parallel. Just blew my son's tractors controller board seeing if it would run 36v

Sounds like the motor is starved of current for higher torque situations. Possibly due to too small of a wire gauge, or if the buck converter current setting isn't turned up to the max setting.

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

I'm not sure. Maybe the buck converter output is noisy? Sounds still work fine on mine.

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

This LOOKS like the same remote that came with mine: amzn.to/3ILQBrK No guarantees it will work, but it's cheap enough that it's worth a shot.

Thank you! We got one before I saw this comment and it'll pair but it won't move it. No clue. Will definitely return and try this one! Any suggestions for a battery charger lol cause I ordered a battery but didn't think about charging it 😅 luckily I got the right battery!

Yes, the remote still works. As long as you buy a DeWalt battery adapter instead of a Milwaukee one, it should work fine.

First, you need to put it in a wading pool full of rice... 😂 Honestly I have no idea - you may want to contact the manufacturer and ask.

I was just going to ask the same thing, I hooked mine up tonight and encountered the same problem

On flat roads it’s starts slow and then essentially hits the turbo LOL and takes off but we have to keep it on flat roads. Please help!!!

you need at least something that can provide 20A continuous

hey i had this issue with the same 300w 20a buck converter basically wouldnt run under load. i bought a larger buck converter 30amp and that solved this issue, i bought the sealed buck converter thats already pre stepped down to 12v which for my little one is more than enough hes not old enough for faster speeds. i just installed mine a little bit ago so i havent fully tested outside until tomorrow

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

Just swap another one in and keep going. But the longest my daughter has driven it at once was 3 miles continuously, and it was hovering between 1-2 bars left out of 4 on a 5Ah battery. I'd plan on swapping batteries every 4 miles so you don't completely kill one by overdischarging it.

Batteries will read a higher voltage open circuit than under load. The 12V rating is for a loaded condition where the voltage sags. All batteries work that way.

@@DoresoomReviews so set mine the same video to 14v?

That's what I would do.

What are the specs on the new motors vs the original ones? It's possible they're triggering overcurrent protection.

@@DoresoomReviews the old engines were 16000 r.p.m and the new engines are 40000 r.p.m. I also changed the battery with a new 12v 9Ah and the old battery was 12v 4.5Ah.

RPM doesn't matter as much as designed operating voltage and current draw.

@@DoresoomReviews ok,thank you very much for your help and time.

The switch could be a current bottleneck. Also if you're using thinner wires it could contribute.

@@DoresoomReviews using 12 gauge wire throughout. Switch says it’s 250VAC 8a/12.5a.

@@DoresoomReviews should I put a dummy wire in place of the switch just to see if that does it?

@@DoresoomReviews what else could be the bottleneck? Still drops voltage on grass

I'd try bypassing the switch first. Also, is it the same model of jeep? And how heavy is your kid? My daughter is somewhere in the 35-40 lbs range.

If it's designed for a 12V battery, you should be able to copy what I did in the video exactly.

@@DoresoomReviews I beleive it is I'm not entirely sure. I'm trying to be safe rather than sorry lighting up the neighborhood with flaming plastic.

Just buy a DeWalt battery adapter instead of a Milwaukee one - that's the only change needed. DeWalt 20V Max is really the same voltage as Milwaukee M18. Both have multiples of five 3.6V cells in series in their batteries.

Yes. I keep an eye on charge level and swap batteries after about 45 minutes just to be safe.

That's why I used the buck converter to step down from 20V open circuit to 14V open circuit. I didn't want to risk burning out the motors or frying any of the circuit boards. If you wanted to be even more conservative, you could set the voltage to 13V, which is the open circuit voltage of the stock battery that comes with it.

No, sorry I don't plan on selling them.

Sorry, I don't plan on selling them. You could always check if your local library has a 3D printer you can use.

Still the weaker one as far as I know.

@@DoresoomReviews i will be doing this conversion in the near future. Did you determine if the batteries cutoff prior to total discharge? Also if I run both the converters do you have a wiring diagram to run both at once? Thanks!

I don't think the batteries have the low voltage cutoff, so just keep an eye on it. My daughter has driven this thing for over three miles on a 5Ah and the battery still had a bar left. I don't have a wiring diagram, but it's the same as with a single buck converter, just with an extra one in parallel. So two wires running from each battery +/- terminal, corresponding to each buck converter's +/- input terminals. Then two wires feeding into each of the car's power +/-input terminals, one from each buck converter's +/- terminals.

I've got links to all the parts in the video description.

Sounds like you're starved for current. Turn the current limiting knob all the way up and see if that helps.

@@DoresoomReviews I didn’t and it just keeps rotating and clicking noise .. it never stops turning

A few other viewers have reported the same issues, but I haven't been able to reproduce them unfortunately. You may want to try a 400W or 500W buck converter to see if that resolves the problem.

I recently discovered the buck converter manufacturer changed their design without updating the product listing. If you bought the two pack, try setting both to 14V independently, turning their current adjusting screws all the way up, and wiring them in parallel between the power tool battery and the vehicle.

I didn't keep count, just turned it 3-4 times maybe. I didn't hit a stop.

Thanks!

"Hit the switch and complete the circuit" just doesn't have the same ring to it! 🤣

The best solution is to just get a multimeter. They're very affordable for basic models: amzn.to/3VyOQUe Or if you have the same model jeep I do, the "radio" LCD displays the battery voltage. You could turn the voltage potentiometer all the way CCW, hook it up to the jeep, and slowly adjust CW until you reach the proper voltage. Initially the jeep might not turn on though, so you'll be without any insight for the first little bit.

I designed it in inches, and most slicers import it as millimeters. Scale it up by 2540% and you're good to go.

Yes, it's this one: amzn.to/3PaR07Z I think we have at least 300 miles on it now, still doing great!

Did you adjust the current and the voltage limiters on the buck converter? Turn the current setting all the way up, and set voltage to 13-14V using a multimeter. Also check to be sure polarity is correct, but if the LEDs are illuminating I suspect it is.

I didn’t check, and did adjust the settings with no change to the unit. To add another variable to my issues I unwired the converter and wired just the m18 adapter direct to the jeep and just lights, still no sound effects, but the jeep would only drive foreword, would not engage in reverse.

Those are strange symptoms. Does it work normally on the original battery?

Yes runs normal on stock battery, but I thinnnnnk I know the reason for the strange symptoms. So stock battery runs on 14V and 11amps, my genius self only ordered one m18 adapter, meaning the jeep was only getting 18V 5amps (battery I used when testing). Only half the amperage… so guess I’m ordering another one

The Amp-Hour designation on the battery is for energy storage capacity, not max current output. So a 5Ah battery can output 1A for 5 hours. Or 5A for one hour, or 10A for 30 minutes, etc. Those M18 batteries can dump a lot more current than 11A. It's very weird that the M18 battery connected directly to it couldn't make it work. Although the car's board might have high voltage input protection? So it may really be that the buck converter can't keep up. But the low current symptoms I was seeing was not enough torque to go up steep hills, not inability for the vehicle to move at all. Is the buck converter the same 300W one that I linked to? I had a friend try it with a larger two seater 12V vehicle, and he said his still has trouble going up hills with two kids in it. Wiring two buck converters in parallel might do it, but I'm not sure.

With the number of people commenting here that the full 18V burned out their circuit boards or motors after a while, I'd definitely use the buck converter to step it down.

It's much easier to just do a battery swap. I'd have to modify a lot more on the jeep to use drill motors to power it.

I've done a 3+ mile drive with my daughter and still had a few bars left on a 5Ah battery. I just disconnect and recharge immediately after she's done driving and haven't had one drain completely yet. But if you want to pass everything through a low voltage cutoff board, you could put something like this between the battery and buck converter: amzn.to/3y671Wu You'll have to have a fairly high rated current, I suspect at least 20A. Also know that a board like this will continue draining the battery after it stops supplying power to the vehicle. So you'll need to disconnect the battery right away after it cuts off due to low voltage.

@@DoresoomReviews Thanks for that. I'm not sure that's the board to use though, apparently it doesn't keep its settings once removed from power. At least according to the comments in the reviews. So every time you change the battery you'd have to configure it again. Good ol Chinese gizmos. I randomly have the Victron BP-65 low voltage disconnect left over from another project, it claims a capacity of 65 amps and remembers its settings. Relatively pricey though at $40. I'll probably give that a shot. Amazing that you're getting that much range on a 5ah battery. The stock SLA battery claims to be 12ah @ 12 volts (144 watt hours), and a 5ah drill battery @ 19v is 95 watt hours. I don't think I get a mile of range on my stock SLA battery, but of course lithium has more usable capacity, and I guess a lot more kick. And lord knows what the real capacity of that SLA battery is. And I'm on dirt 100% roads.

Ah, I missed that that board doesn't retain settings. Good catch! Dirt roads will likely cut down on range, almost all the driving we do is on concrete sidewalks. I couldn't believe the runtime either after the first time we did a longer drive. I stopped to check the battery a few times along the way too. I used the MapMyRide app the second time to confirm how far we had gone.

@@DoresoomReviews That's amazing. Can't wait for the drill battery socket adaptors to arrive so I can try this. Thanks so much for posting this vid, great info.

You'll likely burn the motors out or strip the plastic gears if you try that.

@@DoresoomReviews ok if upgrade the motors & gearboxes i can avoid that, then do you have any thoughts on how to control voltage to other electronics?

You'd have to figure out where power gets sent to the circuit boards vs the motors. If it's split off of the main battery line it should be easy. If it's a board-level split then it will probably be impossible.

@@DoresoomReviews i have the same jeep as yours, i believe its a board level split... you run yours at 14v right? is that the max everything can handle?

I have the same buck converter as you, For the current you said to turn it clockwise? Mine just keeps turning and turning and turning and doesn't seem to be a limit how do you check the current with a voltmeter?

Yeah, I only run 5Ah batteries in it for that reason!

80mm - links are in the video description

I'm working on some 3D printed TPU tire covers!

That's a good idea. I had planned to do exactly that with some bike tires, but then went down a rabbit hole of 3D printing my own seamless TPU treads. They work well for traction, but getting them to stay on the wheel without an adhesive is proving to be a challenge.

Even with the buck converter? Or did you wire it straight to 18V?

M12 is 10.8V open circuit voltage. It will cause the jeep to run slower than the standard batteries do.

@@DoresoomReviews ahh thank you! I just bought the stuff to do m18 to 12v conversion.

Covered that at 6:35

Ha, 36V into a 12V motor? Poor thing didn't have a chance! 😂

@Doresoom Tool Reviews there weren't any labels on anything so I said what the hell and gave it a shot to see what it could take. Lol 18v is fine in parallel but once that voltage goes up then it's done. Lol

No, sorry - I won't be selling these. You could probably find an Etsy seller to 3D print the enclosure for you thougb.

Same exact jeep? My kid weighs around 35 lbs, is yours significantly heavier? I run it at 14V, so 20A is 280W. If you're running at under that voltage, its power output will be lower if it does max out at 20A.

​@@DoresoomReviewssame size kid, same jeep. Only variable is the Ryobi Battery. It starts off normal and then stops after a few seconds, especially on grass. Ive cut out the thermal fuses just to eliminate that possibility but with the voltage dropping so hard at the buck converter under load I have to assume that's the problem. I ordered a 30a buck converter to see how that fares, I'll report back when I get it in.

@@F01EY did the higher amperage buck converter do the trick?

Yes! Works perfectly now. That was the culprit.

@@F01EY awesome, thanks for the reply! I’ve got a 400W in the mail for tomorrow. 🤞

Everyone's got to start somewhere! It can seem intimidating at first, but soldering and wire terminations are pretty easy with some practice! 😊

No, sorry I don't plan on selling them. I'm sure you can find an Etsy seller to 3D print you the enclosure if you want.

You can just ask here.

@@DoresoomReviews im curious if i can use a 20v battery & lower it on the heat sink like you did? Or do i need a different heat sink for a 20v? Does your remote controller still work?

@@DoresoomReviews also does the different gear function still work?

20V max batteries are actually the same voltage as 18V nominal, so it will work fine. Remote still works too .

@@DoresoomReviews have you had to replace any gears since youve made this modification?