Get 12v Out of Your Ryobi 40v Batteries – Great for Powering Your Own Projects & No Soldering Required!

Need 12v for your project and want the easy ability to swap out the batteries so you can recharge them later? With this simple project you can use Ryobi 40v Lithium Batteries to power your own projects that run on 12v. To make it even easier there is no soldering required for this project. The batteries can be gotten for quite cheap during sales and provide pretty good capacity for the cost. Even better if you already have some of them lying around now you can reuse them for anything you want. So lets dive right in and get this project started!

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Here is a complete list of Supplies & Tools you will need. They are not all the same supplies I used but should be similar or better replacements.

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Supplies

• Ryobi 40v Battery Connector – (This slides right onto the 40v battery.)
• 36v 48v Step Down to 12v 30A Voltage Regulator Converter – (30A is probably overkill and is higher then the wires used would be rated, I got higher then needed to give it an extra amperage buffer and to power a larger inverter.)
• Spade Terminal Wire Connectors Set – (This kit provides plenty of connectors in 3 different sizes.)
• Fused SAE to O-Ring Cable 16 AWG (2 Pack) - (This is made out of slightly better cables and has a full size automotive fuse. I have used these with a different project and they are better built. I recommend this or better AWG if you want to draw more amps.)
• SAE to Cigarette Lighter Female Socket Adapter – (This is just the adapter with quite a few feet.)
• SAE Cigarette Lighter Female Socket & Other Set – (This might not be of use for you depending on your project, but for a few bucks more you also get a male cigarette lighter to SAE and a alligator clamp to SAE.)
• SAE Polarity Reverse Adapter – (This will be required depending on what you plug into the SAE connector to keep the positive red cables matched with the positive red cable on the SAE adapter you plug in.)
• Automotive Blade Fuse Assortment – (This is required if you want to change out the fuses that come with the connectors to something higher or lower. This has both large and small style automotive fuses.)
• Optional: SAE to Jackery Adapter – (If you have a Jackery and want to charge it directly this is a good adapter and includes the polarity reverse adapter needed.)

Tools

• Quick Wire Stripper – (Not required but saves time when stripping wires.)
• Wire Stripped & Crimper – (This is required to do the crimping on this project and can strip the wires as well.)
• Angled Wire Cutter Set – (Any wire cutter will work, and the above tool also has a wire cutter.)
• Auto-Ranging Multimeter - (This is a similar style to the one I am using, any multimeter you have should work. If you don't have one this is not required it is just used for testing.)

First we will cut off the O-Rings attached to the SAE cable to prepare it for the next step.

Now strip the ends of all wires just enough so we can fit the connectors seen in the next step. These pictures also show how the quick wire stripper tool works, you just put the wire between it and give it a squeeze and the wire is stripped.

With all the wires stripped now crimp a connector on all the wires, on mine I went with 2 male connectors on the Ryobi 40v Battery Connector end, followed by 2 female on the input end of the Step Down 12v Voltage Regulator. I then put 2 male connectors on the output of the voltage regulator and last 2 female connectors on the SAE cable. The wires on this cable were a bit smaller so I folded the stripped wire in half to make it fit the connector better. I did it this way so you cannot connect the battery to itself, which would short it out, and so I can also connect the SAE cable directly into the battery without the 24v step down voltage regulator.

Now that all the ends are crimped I test the connectors on the Ryobi 40v Battery Connector. It should be somewhere around 40v when its fully charged, like this one is. If you don’t see a voltage check the fuse and make sure your crimps are on the stripped wire and not the casing of the wire. I used alligator clips on the ends of my multimeter for easier picture taking.

The Ryobi 40v battery connector works, so lets plug it in to the input part of the voltage regulator and connect the multimeter to the outputs. Be sure you connect positive to positive and negative to negative. The inputs and outputs are marked on the back of the voltage regulator. It outputs almost exactly 12v.

Now that the voltages have been tested its time to attach the female SAE Cigarette Lighter Adapter and you are done with the project. You can attach anything that runs on 12v and draws less then the max amps your battery can output and the wires used in the project. The 12v voltage regulator supports a max of 30A so you cannot exceed that and you should leave a buffer so maybe 25A. However, the wires used on the SAE connector end will probably make it closer to 10A - 15A max, which is fine for my needs. The last few pictures are also of a car USB cigarette lighter charger charging a battery pack.

This can easily power an inverter depending on the max draw you try to run through it. It will not be able to run the full 500w of the inverter shown in the picture, that was just for demonstration. It could easily do up to 300w or so inverter with better SAE connector wire guage. If you are running something like a laptop you would be better to get a 12v DC laptop charger like this one. The Ryobi batteries have a built in Battery Monitor Systems (BMS) that will prevent over discharge, but it is still a good idea to keep an eye on its charge level and stop around 1 bar left on the battery meter. Ideally, the half way mark if you want to prolong the batteries overall life, as full charge cycles cause more wear to lithium ion batteries faster.

With the Jackery SAE Connector you can also use this to charge your Jackery. You could also use the 12v cigarette lighter charger that comes with most Jackerys. It will input at around 30w until the Jackery nears 100%.

This system will work for more then just Ryobi 40v Batteries and can easily be modified to fit many other power tool battery systems. You could easily have it work for any 48v or 36V lawn care power tool batteries depending on what 12v Voltage Regulator you get. As long as the fully charged battery input is below the 24v max the Voltage Regulator used it should be able to handle it. If you want to use another power tool battery instead of Ryobi simply type in the brand of your power tool plus battery connector into amazon here. That link will take you right to a search of power tool battery connectors on Amazon. You can see them for all sorts of brands such as DeWalt, Milwaukee, Porter Cable, Kobalt, Black & Decker, etc. That's just from the first page, there are a lot more brands too, and it doesn't matter if its a stem type or rail type battery, there is almost always an adapter you can find. So any type of power tool battery, just about, that you have already or can get for cheap could be used and can be used with your 12v projects or Jackery.

If you would like to support me in making these projects you can do so here.

If you want to get 12v out of your Ryobi 18v Batteries see my other project here.

If you want to get USB 5v out of your Ryobi 18v Batteries see my other project here.

Do you have any more suggestions? I will add good ones to this list and if there is enough demand I will possibly do some of these ideas in the future.