Ryobi 40v Battery Not Charging? (Possible Causes & Fixes)

Ryan Womeldorf
by Ryan Womeldorf

Ryobi makes some of the most affordable, quality power tools on the market. If you are new to the DIY game or consider yourself just qualified enough to tackle most household problems, you probably have something from Ryobi in your toolbox.

Despite the inherent quality, they are not impervious to issues. If you go to use your 40v battery and notice that it isn’t working, there are likely a few common reasons. It could be that the battery has switched to “sleep mode” and just needs to be reset. It could also be that the battery has been exposed to extreme heat or cold. Finally, it could be that the battery terminals have become dirty or corroded. Depending on the issue at hand, there are some possible fixes at play here.

Possible Causes For Ryobi Battery That Won’t Charge

Generally speaking, you know there are issues when one of two things happens. The first is that you see red and green lights flashing on your Ryobi charger. The second is when there is no response from the charger at all.

If you see flashing lights, it isn’t all bad news. In this instance, it at least seems like a fix may be possible. Should you notice that the charger or battery is completely non-responsive, then you will likely have to replace one or the other. In the worst-case scenario, you will have to replace both.

Battery is in Sleep Mode

Perhaps the most common reason that your Ryobi 40v battery will not charge is that the battery has over-charged. You may also hear this referred to as going into “sleep mode”. You will sometimes even see the aforementioned flashing red and green lights.

What does it mean when a battery is in sleep mode? Well, it means that the battery has been discharged at such a low level that the charger can’t really detect if the battery is healthy or damaged. It then decides to not risk issuing a charge, displaying those flashing red and green lights instead.

Some Ryobi chargers may have a “boost” function that allows the battery to be woken up, but this isn’t all that common. Instead, you will have to implement a fix.

Bringing the Battery Out of Sleep Mode

Thankfully, there are a few possible fixes when it comes to the dreaded sleep mode. That said, as is the case when it comes to DIY fixing cordless tool batteries, there are some potential dangers at play. You may even see recommendations that you do not boost a battery that has been in sleep mode for longer than a week.

So, as you read on, keep that in mind. That said, there are generally three options for bringing your battery out of sleep mode.

Fix 1: Using Another Battery

In order to “boost” your battery out of sleep mode, you will need a second battery. That second battery must be fully charged and healthy. Furthermore, that battery has to have the same voltage to work successfully.

  • Connect the terminals. Make sure that you pair up the terminals with matching polarity. That means positive to positive, negative to negative using wires. Leave them connected for a couple of minutes to “boost” the battery.
  • Try again. After a few minutes of connecting to the healthy battery, give the first one a try again. If the first battery is in good condition, it may be enough to “boost” it back to life. If not, you can move on to trying some of the other fixes.
Fix 2: DC Power Supply

Should the first fix fail, it is time to move onto plan B. If you have a DC power supply that is set to the same voltage as your battery, you may be able to boost it this way. The principal is the same as the spare battery: you are using a healthy booster to try to jump the old battery back to life.

Once again, connect the terminals to their matching polarity (positive-positive, negative-negative). Give it a little bit of time and then try to charge the battery. When you successfully bring the battery out of sleep mode, the charger should flash as it normally does. If that is a no-go, then there is one final option.

Fix 3: The Longshot

This is the step that should be used if you do not have a spare battery, nor do you have a spare power supply to use. That means the boosting option has passed and you are in Hail Mary territory. Still, this has been noted to work so it’s not impossible.

Above all else, you need patience for this to work. Follow these steps as well:

  • Plugin the charger and battery. Start by connecting your charger to a power outlet. Take the battery and place it on the charger. In most cases, you will see a solid green indicator come on.
  • Remove the battery. Before the charger can switch over to the flashing red/green light, pull the battery from the charger.
  • Repeat. Keep re-inserting the battery into the charger. Keep doing it until the green light continues to flash instead of switching to the red/green flashing lights. It is not unheard of for this to take up to 30 minutes, so try to be patient.

The reason this works is similar to the other methods. Each time that you insert the battery into your charger, it gives it a little bit of a charge before it detects that the battery is sleeping. Those cumulative charges are what can potentially boost the battery out of sleep mode.

Battery Gets Too Hot or Cold

Going into sleep mode is not the only reason why your battery may fail to charge. Despite the durability of Ryobi tools, no battery is meant to be left exposed to extreme temperatures for long periods of time. Proper storage is imperative for the life of your power tools.

This is one of the main problems with lithium-ion technology. The older styles of battery didn’t hold a charge for nearly as long but leaving them exposed to the elements wasn’t a big deal. There is a range for lithium-ion batteries to charge: between 32F and 113F (or 0C to 45C).

  • Check the temperature. If your batteries are displaying issues, check the temperature first and foremost. In extreme cold or heat, it is common for batteries to start experiencing issues.
  • Extreme cold. On exceptionally cold days where you might be either storing or charging your batteries, bring them inside. Give them a bit to get back up to room temperature and then try to charge them again.
  • Extreme heat. On the hotter days, or if you have been using your battery and it’s getting really hot, cool them down. Either let them sit in a cool, shaded area or throw them in the fridge for a short period. It’s the same principle: get them into that charging range from a temperature standpoint.

Dirty or Corroded Battery Terminals

Finally, there is one last issue that could be keeping your Ryobi 40v battery from charging. When the metal that contacts the battery either becomes dirty or corroded, then it can play a trick on the charger. The charger will be unable to detect that the battery needs charging, simply assuming It to be full.

  • Cleaning. Ideally, the terminals will simply be dirty. In that case, you can remove the dirt pretty easily. Either use a wire brush or an alcohol wipe to clear away the dirt. Verify that the charger works when you are done with the cleaning.
  • Sandpaper. Should you be staring down corrosion instead, don’t panic. Usually, you can get the corrosion off with a little bit of sandpaper and some elbow grease.
  • Recessed terminals. In the worst-case scenario, you may be looking at recessed terminals. When they have become recessed, you may have a substantially more difficult time getting to them. You may have to get creative when it comes to cleaning them or removing the corrosion in this scenario.

What if None of Those Works?

If you have gotten this far, you have likely tried everything listed and maybe even more. Still, you can’t get your 40v battery to charge. So, what is the problem? Well, it is typically down to one of two things at this point. Either the charger is faulty or the battery is.

Try testing out the battery before immediately replacing it. Perhaps the best way to find the answer is to take the battery to a local home improvement store that sells Ryobi tools. Try your battery on one of their chargers. If you get the same result, the battery is bad. If it charges, then you know the charger is at fault.

In either case, you are looking at replacing a part. For replacement Ryobi batteries and chargers, you can find a local supplier with a cursory Google search. If you don’t need them right away, then you can check out an online retailer like Amazon to save a little cash.

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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