If you see an error light flashing on an Atlas charger, that means battery pack has fallen into a range of voltage where charging is no longer considered safe. It could also mean your battery are defective and is showing up as bad cell pack in the unit.
There are tested ways to bring a dead battery back from the brink that will NOT require tossing it out. Try one or all three of these resets to get the charger to recognize it again.
You can jump-start using an Atlas to Atlas method. For this method, you take a working Atlas pack and simply plug it into your dead one. If you are lucky enough to have another pack handy, this couldn’t be easier. Before you begin make sure you identify which terminal is positive and which is negative on each pack. Connect positive to positive and negative to negative. It’s that easy and it keeps you safe too.
For example, the dead battery might only be a small 2.5Ah unit while you have an 8Ah donor unit. It doesn’t matter. Just make sure polarity is maintained so there’s no risk of instant short circuit. Gently connect the leads from one pack to the other taking care to form a solid yet brief link.
Never, ever get your terminals mixed up. Always connect positive to positive and negative to negative on opposite side. Push the wires into position and hold for a second or two to raise voltage slightly. Then maintain the connection for about 15 seconds to activate the onboard protection circuit.
If you notice any burning or see smoke, pull out those leads! That means something has gone wrong and it’s likely done some permanent damage to your equipement. When you’re waiting for the transfer to finish, keep a close eye on it.
Once 15 seconds have passed, remove the leads. Your dead battery should now register sufficient voltage for charging.
Using a Compatible Battery Donor
Or, you could use another brand’s compatible battery (and, ideally one that is close in voltage). For instance, a 40V Greenworks will fit into the 36 to 40V spectrum. If so, it becomes a compatible battery that you can use as a donor pack.
Now match up the positive and negative terminals on your external battery. It may not have the same terminal set-up as Atlas packs. Note the location of the pins in the connector area on the bottom. This helps you know how to connect it properly. Positive from the donor pack should be connected to positive on the Atlas battery. Negative is then attached similarly.
Carefully insert your small wires into the terminal areas. Make sure they’re solidly connected before continuing the transfer. Again, let the connection be active for about 15 seconds. Pay attention to any burning smell and overheated wire.
Don’t mistakenly short out the terminals while doing this. It will trick the charger just like the first time. The voltage increase is almost unnoticeable but it works. If these don’t solve the problem, you can try the third method mentioned above.
The third is a controlled DC power supply. For this one, you can set it to anything between 30V and 40V. With a bench supply, you get exact control of what’s being supplied. While charging, the voltage and current is displayed in real time.
Then set the charge limiter (current) to 1A, which will protect the cells from getting too much current. Slowly turn the voltage knob up to whatever your desired voltage is. After attaching the leads, you may need to bump it up a bit more graduallly as necessary.
Connect the positive lead from the supply to the battery positive terminal
Connect the negative lead from the supply to the battery negative terminal
Always make sure you have the polarity correct… There is no margin for error here. If you use a regulated DC power supply, the display will show the voltage rising as you connect.
Plug it in and see the numbers increase on the screen. Be sure to keep it plugged in for about 15 seconds here. Watch your leads, don’t let them get hot or start to melt. If they do, unplug right away. No need to adjust settings and cause a short circuit.
The power supply protects against overloads somewhat, but external shorts can still cause issues. It doesn’t do anything if you short something out externally. So be careful of exposed metal while doing this.
In the boost mode, the voltage will hit around 37V. That should be enough to trip the pack and get rid of error while waking it up.
At this point, there shouldn’t be much current draw during this process. If it’s stable, you know the cells are taking a charge as expected. Now attempt to put battery on its original charger.
This voltage bump should of done the trick and allow the battery to function properly. Put the battery in the charger and see if it works.
If the LED stops blinking an error code right away, then you’re home free. Restore voltage and insert the pack into the charger. Most of the time, it will begin charging normally right away. This indicates that your pack wasn’t really dead after all, but was just stuck in a low-voltage protected state.
