How To Fix Common Ryobi 40v Battery Problems

In my opinion, Ryobi cordless tools are some of the best available, although it does seem that the batteries can suffer from numerous problems. Replacement batteries are certainly not cheap, and most of us will want to avoid the need to buy a new battery if at all possible.

So I have some good news for you; it is possible to fix most Ryobi 40V battery problems yourself.

Let’s take a look at the most common Ryobi 40V battery problems and how to fix them.

ryobi 40v battery problems

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Why Do Ryobi 40V Batteries Fail?

The most common reason that a Ryobi battery fails is because it has entered sleep mode. This happens when the battery has been discharged too much. This typically happens when a battery has been used till it is flat, and then stored without charging for a long period of time. The charger is then not capable of providing enough voltage to “kick start” the battery back into life.

When this happens, your charger will likely have red and green lights flashing when you try to charge the battery. Let’s take a look at how to solve the problem.

Ryobi Charger Red And Green Lights Flashing

Whether you have a Ryobi cordless mower, a pole saw, a leaf blower, or one of the many other tools available, a common problem with Ryobi batteries is when the charger shows green and red flashing lights.

Well, don’t panic yet because it isn’t always a sign that your battery needs replacing.

There are ways to attempt to fix this problem; take a look at the possible fixes below.

rgenuine ryobi battery

Ryobi Replacement Battery

Genuine Ryobi 40V Battery

  • 4 aH High Capacity Battery
  • Compatible with all Ryobi 40V Tools
  • Built in battery life indicator
  • Genuine Ryobi Warranty and Support

Ryobi Battery Entered Sleep Mode

battery sleep mode

The most common cause for your Ryobi Charger showing flashing red and green lights is that the battery has been over-discharged.

This is commonly known as the battery is in “sleep mode”

What this means is the battery has been discharged to such a low level that the charger has trouble detecting if the battery is healthy or not and decides to not risk charging it – showing the dreaded flashing red and green lights.

The problem here with Ryobi 40V chargers is that they don’t incorporate a “boost” feature that would allow a battery that has entered sleep mode to be woken up again.

How to fix this (maybe);

As with any DIY fix with cordless tool batteries – it does have some dangers involved. Battery university recommends not boosting batteries that have been in sleep mode for a week or longer.

So keep this in mind when carrying out the following recommendations.

There are two ways to try and wake up a sleeping battery.

The Fix Option 1 – Micro Charges:

This method is the easiest, safest and simplest method to try to revive your Ryobi battery that won’t charge.

Patience is required here – so read these instructions carefully and find somewhere comfortable to sit!

  1. Connect your charger to the power outlet
  2. Place the battery in the charger until the green indicator goes solid
  3. Just before the red/green lights start flashing, remove the battery from the charger
  4. Re-insert the battery into the charger again and repeat steps 2-3
  5. Do this until the green light flashes constantly (might take up to 30 minutes)

Why does this work? Well each time you insert the battery into the charger, it gives it a small amount of charge before detecting the battery as sleeping.

So repeating this process over and over results in the battery slowly being charged in very small increments each time.

Eventually, this results in enough charge for the battery charger to resume normal charging operation.

It may sound crazy, but the graph below shows why it works. Also, take a look at the many pages of comments below this article to see just how often it actually works!

ryobi battery problems

The Fix Option 2 – Use a Second Battery To Jump Start The Sleeping One:

ryobi battery fix

Use a second healthy, fully charged battery of the same voltage and connect the terminals matching polarity (positive-positive, negative-negative) using wires and leave them connected for a few minutes.

Then try charging the battery again – this may be enough to kick the battery back into life. You can see a video guide on how to do this here.

The Fix Option 3 – Use a DC Power Supply:

Use a DC power supply set at the same voltage as the battery and connect the positive output to the positive battery terminal and the negative output to the negative battery terminal.

Once again, leave this connected for a few minutes then try charging the battery.

Genuine Part
rgenuine ryobi battery

Replacement Charger

Ryobi 40V Battery Charger

  • Compatible with all RYOBI 40-Volt lithium-ion tools and batteries
  • USB power source for charging your small electronic devices when plugged in
  • Advanced Charging technology for battery protection and extended life
  • For use with RYOBI 40-Volt batteries only
  • Featuring innovative charging technology

Battery Too Hot or Cold – Ryobi Charging Temperature

So, while we all love the Li-Ion technology of modern-day batteries, it does have some problems that older styles of battery didn’t have to worry about.

One of these being the narrower range of temperatures that they will operate, and charge in: Li-Ion batteries will generally charge between 32°F to 113°F (0°C to 45°C).

So, the first thing to check if you are having problems with your Ryobi batteries is if they are indeed too hot or too cold.

If it is exceptionally cold where you usually store/charge your batteries, bring them inside and let them warm up to room temperature and then try charging them again.

If it is a hot day, or you have been using your batteries already and they are quite hot, try throwing them in the fridge, or taking them to a cooler area for a short amount of time before trying to charge them again.

Corroded or Dirty Battery Terminals

If the metal contacts on the battery or charger become dirty or corroded, then it can cause the Ryobi charger to incorrectly assume that the battery is faulty.

If your terminals are corroded: then the corrosion can be removed with a piece of sandpaper.

Dirt on the terminals can be removed with a wire brush or an alcohol-soaked wipe.

Sometimes getting to the actual terminals can be difficult due to them being recessed, if this is the case you will need to try different tools or items to reach them for cleaning purposes.

What If None Of These Solutions Work?

Unfortunately, if none of these solutions solve your Ryobi battery problems then it is likely you have one of two problems: 

  • Either your battery is faulty
  • or your charger is faulty

Here is what you can do next:

The best way to test which is the faulty part is to take your battery down to your local store that sells Ryobi 40V tools and try it on one of their chargers.

If the same fault occurs then you have a faulty battery, if the problem does not happen on a different charger then it is likely a faulty battery charger.

Where Can I Buy Replacement Parts?

If you need your replacement Ryobi 40V battery parts in a hurry, then you will want to head straight down to the closest supplier and buy it locally.

If you aren’t in too much of a rush and are looking to save some cash, then consider purchasing from a reputable online store such as Amazon.

Click here to see a selection of Ryobi 40V Batteries and Chargers.
Also Available at Home Depot

Are Non-Genuine Ryobi Parts Available?

Yes, they are! Some are great and work well, others are not worth the time or the money.

rgenuine ryobi battery

Ryobi Replacement Battery

Genuine Ryobi 40V Battery

  • 4 aH High Capacity Battery
  • Compatible with all Ryobi 40V Tools
  • Built in battery life indicator
  • Genuine Ryobi Warranty and Support

Ryobi Battery FAQ

Can a Ryobi cordless tool battery be repaired?

The short answer is yes, but the longer answer is that it probably isn’t worth the time or the hassle.

Opening up the batteries can be difficult and depending on what part if faulty, it may be quite expensive to fix.

Remember that batteries can be dangerous, so it’s best to get a qualified technician to check the battery for you.

Is it OK to leave a Ryobi Lithium-Ion Battery On The Charger?

No, you should charge the battery after use till it is full, then remove it from the charger and store it in an area that doesn’t get too hot or cold.

The ideal battery storage temperature is around 59℉, but standard room temperature is usually fine.

About The Author

Aaron is the founder of and Essential Home and Garden. He likes to spend his spare time with his family, and doing DIY projects in the home and garden.

267 thoughts on “How To Fix Common Ryobi 40v Battery Problems”

  1. Fantastic, I plugged my battery in and unplugged it 3 times and now it is fully charged.

    How did you know this?

  2. Hi,
    Thank you very much for sharing your insight. I have a 40v Ryobi battery than when plugged into the charger the charger light stays green but the battery doesn’t charge. At this time what can I do? Please help me?

  3. Aaron, thank you, Fix Option #3 worked like charm for my Ryobi 40V. Required about 4-5 minutes of in-and-out but then the green stayed solid and battery is charging. Thanks!

  4. Hey Aaron,
    I have the ryobi mower with 2 batteries. This year I have one battery that won’t work in the mower despite showing its fully charged by the tester. The charger works fine to charge the other battery and the mower works. Any ideas?

  5. Arron my Ryobi charger shows solid red the battery has no charge and the light stays red when i try to use the weed eater it goes for a second then stops then goes the again any suggestions will be nice

    • It sounds like the battery is not being charged – or possibly even that the charger is not detecting that a battery is plugged into it at all.
      This could be a tricky one to diagnose. First thing I would do is clean the terminals on the battery and the charger. The second thing I would do is try to ascertain whether it is the charger or the battery that is faulty. Do you have any other batteries that work in that charger?

  6. Aaron
    I have two Ryobi 40 volt Lith to run a chainsaw, 1 battery shows fully charged both on the charger and on the lights on the battery but will not even try to run the saw, the second battery shows defective on the charger ( red & green Lights flashing) with only one light on on the battery but runs the saw just fine.
    Any idea’s


  7. I bought a 40v weed eater and charged it last night to full. This morning I used it until it quit and tried it again and it quit again so I put it in the charger and got no lights. I left it in for a couple hours and still nothing. Any suggestions?

  8. I have a 40 v mower with 2 batteries about 4 yrs. old one battery works fine the other stops with 1/2 charge showing on the indicator can it be fixed or should i replace it ?

  9. Just bought tjhe ryobi 40v mower and after charging all night, I used the next mor ing and the charged last 10-15 min. I called support, they said thats not normal and to try fully charging 3-4 times and it “should” last longer. It doesnt make sense to me as to why it would make a.difference but I’ll try. Dpes this sound normal to anyone??

  10. Hey this is Sam Peters. I have a battery ryobi trimmer with attachments. I bought a new battery. However when i was outside trimming the yard, the trimmer stopped and then started again. That is even with the battery in and the triggers engaged, it was unresponsive. Then i took the battery out and put it back in and still nothing. Then after a couple of minutes it started working and I was able to get finished. Wondering what it could be?

  11. I bought a Ryobi line trimmer that has a 40V lithium ion battery and charger. I have it plugged in to (re)charge, the “charging” light is pulsing. I don’t think it’s charging because the “charged” light has not come on and it’s been on for several hours.
    Do I have a faulty battery?, faulty charger? This is new equipment purchased a couple of months ago. Should I take it back to the Home Depot where I got it and get a replacement battery or charger?
    Thanks, Sarah.

  12. Hi! My battery has worked great for about 5 years—this year however, I noticed that neither the charger or battery are lighting up when I attach the battery to the charger. The battery held its full charge from the fall and I used it, but now that it died, it won’t recharge. Does that sound like the battery or the charger? I just ordered a new battery online, I’m hoping it wasn’t the charger

    • Hi Sharon, Sorry but it does sound more like a charger issue to me. It seems like the battery has gone completely dead, and because the charger is dead (no lights) the battery won’t work anymore either. Look at the positive side though, you will now have two batteries to use!

  13. An issue with this battery…any advice?
    The battery works to start the mower but once you turn the mower off, if you go to restart the mower you have to pull the battery out and reinstall it for it to work?

  14. Arron,
    Can you tell me what signal the t1 terminal needs to tell the charger to put out the 40 volts? If I connect the ground it goes to defective even though the battery has 39 volts. I’m just trying to get the power supply in the charger to turn on.

    • Hi Vincent, Sorry but I am not sure. I havent currently got any of the devices here to check how they work at the moment. Maybe someone else can help out if they read this.

  15. Is there a way on the charger to bypass the sleep check function?

    Or if I had another charger from a different manufacturer with the correct voltage does anyone know what the electrical connections are inside the battery that need to be connected to.
    I saw one source online that showed the hook up, but it was for a ryobi 40v but the main board inside was constructed different than the board in mine

  16. I habe a 40v ryobi battery than when plugged into the charger the charger light stays green but the battery doesn’t charge nor work in any tool. Can that be fixed

  17. I had the same issue as Larry W. Connections are clean. Continued trying the fix even though the lights were just flashing red & green continuously. Now my charger just flashes red & green even without a battery attached. Any advice?

  18. Hi Aaron, I think you are the expert I should ask my question. I got a Ryobi 36v charger BCL3620S. When the charger is empty and first plugged in, it showed flashing red light ( the manual says it should be steady red light). After I put the battery in, it was still flashing red lihgt and not charging.
    Then I tried plugged in the charger with the battery already in it. This time the flashing red light quickly turned into flashing green light for a couple of seconds than came the alternating red and green light. I had tried option 3 but the battery still couldn’t charge.
    Do you think I got a defective charger or a defective battery?


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