My Alta X 12S Flight Packs are not charging. Can they be recovered?

If your Alta X flight packs are not charging, this may be due to the packs falling to a low voltage state. This can occur due to neglect and lack of maintenance or regular use from flying and charging. You can test the packs with a standard multimeter or by plugging them into your charger. If the main voltage number reads at or below 40v, this is likely the reason for failure to charge. 

There is a method that can be used with caution to attempt a recovery of the batteries and restore their voltage to normal levels. This may then allow the standard charger to recognize them and properly balance charge them again.

NOTE: The following recovery method should only be attempted by someone with proper electrical knowledge and steps need to be taken to mitigate fire risk. Charging a battery without a balance charger carries additional risks.

The primary risks involved with this recovery method are: 

  1. Trying to charge the batteries too quickly.
  2. An individual cell overcharging in the recovery process.
  3. Allowing open battery leads to short and spark while connected to battery
  4. In the worst case scenario, a fire due to a severely damaged battery. 

Please attempt initial recovery at your own risk with batteries on a concrete or similar  non flammable surface and away from flammable materials. With cautions noted, this has proven to be a successful method of recovering low state of charge Alta X flight batteries. 


  • You’ll need a standard 60v bench-top power supply. Something like this or a similar power supply should work well.
  • XT-90 Charge leads that can connect to the power supply.
    • CAUTION: If batteries are connected to charge leads with open contacts, a short could occur and cause sparks or fire. Always make sure to connect loose battery leads to the power supply prior to connecting to the battery. Battery leads like this should work well.


Once you have the required equipment you can proceed with the recovery in a safe location:

  1. Connect the power supply to a power outlet
  2. Attach the banana plugs of the XT-90 lead to the power supply. Confirm polarity is correct with Positive and Negative plugs correctly corresponding with the ports of the power supply.
  3. Turn on the power supply and turn the Amp knob to the lowest setting.
  4. Turn the voltage knob until set to approximately 50v. On most power supplies, this will not be seen until a load is applied.
  5. Connect the battery to be recovered to the power supply
  6. Slowly increase power / amperage knob to somewhere between 0.5 and 1.0 amp output.

At this point, the voltage readout of the power supply should start to slowly increase by fractions of a volt at a time. Do not allow the battery to charge unattended. The battery should be removed when it has reached around  40 – 41v and standard balance charging can be attempted again with the standard balance charger. If the standard charger allows charging, keep an eye on the individual cell voltages to confirm they are even and balance out properly.

If this method is successful, congratulations! Proceed using the batteries with additional caution for the next several charge / use cycles. Remember to regularly check batteries when not in use and balance charge them to help avoid this from occurring again. Once every 1-3 months should be sufficient.

If this was not successful, it means the battery was too imbalanced or experienced a cell failure due extensive time in an undercharged state. Please arrange to have the batteries properly recycled.

Still need help? Get in touch with our support team.

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