It is important to always
adjust your charger correctly
for the size and type battery
you are charging.
How To Charge LiPo Batteries
Powering uP safely and efficiently
The old-school chargers I started out with had
one pair of leads that connected to the power
leads on the battery. Either you selected the
cell count as part of the startup sequence, or
the charger would read the battery voltage and
guess at a cell count for you. Both methods
were susceptible to error for various reasons. If
you weren’t careful, you could end up charging a
3S LiPo at a 4S voltage, which would lead to an
Modern chargers have a connection for the
battery’s balance lead, so they can balance
the battery’s cells as they charge. This has
several advantages over the older chargers.
First, balance charging is much better for the
batteries. Second, the balance lead gives the
charger an accurate way to count the cells in
a battery and measure the voltage of each
cell. If the charger knows the cell count and
it has been programmed to stop charging at
an appropriate cell voltage, it becomes much
harder to make a mistake. If the charger has
the cell count and the cell chemistry (LiPo, LiFe
[lithium iron], etc.) has been selected, then all
that remains for a balance charge is to set the
charge current. All of the LiPo batteries that I’ve
used can be safely charged at a rate equal to the
battery capacity on the label, otherwise known
as a “1C charge rate.” A 5000mAh battery,
for example, would charge at 5000 milliamps
or 5 amps. Some manufacturers allow higher
charge rates and will note that on the label as a
multiple of C, such as 2C or 3C. While it might be
safe to charge batteries at these higher rates if
you need to, sticking with a 1C rate for routine
charging will help the batteries last longer.
Here’s the process that I go through every time
that I charge a battery of any size. Doing it the
same way every time as part of a routine helps
eliminate errors that might cause problems:
• Check the battery with a voltage meter to
make sure that it actually needs charging.
A battery checker that shows individual cell
voltages is best.
• Plug the power leads from the battery into the
• Plug the balance lead into the balancing port
• Confirm that the cell count shows up correctly
on the charger display.
• Set the charge current equal to the battery
capacity on the label for a 1C charge rate.
• Start the charge cycle.
• Verify that the voltage and current being
applied to the battery are appropriate.
• As the charge continues, monitor the process,
checking individual cell voltages. If something
doesn’t look right, stop charging and correct
the issue before continuing.
A LiPo battery’s label has a lot of information on it:
cell count, nominal voltage, capacity in either amp
hours (Ah) or milliamp hours (mAh), and a recommended
discharge rate or two in terms of a multiple of the capacity. This
discharge rate is the dreaded “C rating,” which is a topic for another
day. The only things you really need to know to charge a LiPo well
and safely are the battery voltage or cell count and the capacity.
Tex T & Pho Tos by John KauK