Ryobi 18v Battery Won’t Charge; How to Troubleshoot?

The main reason why a Ryobi 18V battery won’t charge is having one of its cells discharged too much. When one of the cells gets discharged, the 18V battery will automatically switch to sleep mode and will not respond to charge. To know whether the battery is in sleep mode, you will have to check whether you can see the flashing of charging lights in red and green colors.

If you are unaware of what has happened to your battery, ensure you follow this article to help you spot the issue and help you troubleshoot the problem. There are times when the battery will not charge even after troubleshooting. You, at that time, need to seek help from an expert. This article contains all the main reasons why a battery may not charge and how to troubleshoot them.

The battery pack is out of balanceThe battery pack is out of balance

A Ryobi 18V battery is made in such a way that it has many individual cells. Sometimes, the cells may be out of balance, and so they tend to hold different charges. Such an occurrence can lead to a major problem, and hence it should be addressed with immediate effect.

Causes of cell failing

  • It could be the cell is not able to hold a charge anymore
  • The cell might not accept charge
  • Differences between the cells in holding charge. If this happens, one of the cells will be out of voltage for the other different cells. It mostly occurs in very old batteries when the difference between the cells’ voltage is too large.
  • Voltage may fall below the voltage cut-off level. Most batteries have the cut-off voltage level inbuilt. If this problem happens, it might prevent the cell from functioning. There are different methods to fix battery packs that are out-of-balance.

Methods of fixing out-of-balance battery packs

You should try this only if your battery pack warranty is expired. If the warranty is still on, send the pack back to where you bought it for repair or where it needs to be for a replacement to be done.

1. Charge only one cellRyobi 18V Battery Won't Charge

You must open the battery pack for you to charge just one cell. After you are done opening the pack, you can now check the voltage of each cell. Where needed, charge the specific cell by using a bench supply. You are required to charge the cells within 0.1v of the other cell.

When you are done charging all the cells, it is time to reassemble the pack and after you have tightly done so, charge the battery pack to see whether it will now respond to charge. If it does, you are good to go, but you need to move to the next method if it still does not respond.

2. Try jumpstarting the battery from a similar type of batteryTry jumpstarting the battery from a similar type of battery

In circumstances where the pack has over-discharged, the charging system will hinder it from charging and get the battery back to work, and you need to jumpstart it by using a healthy battery. You do this by connecting both the good and the bad battery for a few minutes. With this, the dead battery is given a temporary charge which then fools the charger, and it starts working.

It would help if you also tried measuring the voltages by using a multimeter. Follow the steps given below to ensure the connections and disconnections are systematically done.  

Step 1; to access the individual batteries in the battery pack, remove the outer casing

Step 2; on your battery pack, locate the negative and the positive terminals.

Step 3; you need to have a multimeter. Once you have your multimeter, measure the voltages at both terminals in which the resulting voltage should be very low.

Step 4; find a working battery and connect it to the faulty battery. The connection should be the positive terminal of the working battery connected to the positive terminal of the spoilt battery, and the same should be done as per the negative terminals. The connection should be direct to the batteries and not via the circuit board.

Step 5; leave the connection for about 30 seconds

Step 6; Take your multimeter and check the voltage of the bad battery. It should have slightly increased.

Step 7; assemble the battery pack in its right state and then plug in the charger. If the process is successful, the charger should not start functioning appropriately.

How to know if your battery is bad?How to know if your battery is bad

As earlier stated, a battery pack contains a series of cells, and if one of them is damaged, it makes the whole battery pack unusable. Steps on checking the condition of your battery.

  1. Plug your charger and switch on the power. Leave the battery to charge for about an hour.
  2.  Connect a multimeter to the terminals of the battery to help you measure the voltage.
  3. The battery voltage should read a higher value than the one stated on the side of the battery. If the reading is below the one stated, then the battery needs an immediate replacement.

When not loaded, the battery can show the accurate voltage, and also the voltage level can fall immediately after the battery is loaded. If a battery pack is fully charged, it should serve your tools for a longer period than when it is not fully charged. If the fully charged battery pack does not serve for long, then you should consider it damaged and needs to be replaced.

Tips on how to maintain your Ryobi battery

  • When charging your battery, always ensure that the room temperature is favorable, between 50- and 100-degrees F.
  • Be cautious about how you store your battery. The battery should be stored in a dry place, and the temperature should not be too hot nor too cold.
  • Have a regular check on your battery. If the battery is not in use, it should be charged between four to six weeks to maintain its good condition.
  • When charging is complete, always plug off the charger and switch off the power. Then remove the battery. Do not assume that even if the charger has a cut-off, it is prone to fail, making the battery overcharge.
  • If the battery becomes extremely hot when using, you should not connect it to a charger before it cools down. Always give your battery ample time for cooling and then charge it once it is at cool temperatures.


If the battery pack plugs into the charger, the battery’s contacts may be bent or even damaged. You should carefully bend them out by using a pair of pliers for a steady connection. In circumstances where the soldered wires are loose, you need to resolve them tightly to ensure a smooth connection. When charging, make sure that the charger is tightly plugged into the socket, and the battery is also inserted well. If the insertion of the battery is done correctly, a click will be heard.

If you do not want to dismantle the pack, you can use the shock recovery method where you need to put the battery into the charger, then plug in and out the charger using the main connector and then try to achieve a speed of about three times a second. After some time, leave the charger connected, and the red light should show up. If it does not work with the first attempt, try it several times, but if it does not respond, contact an expert.

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