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Charge voltage in excess of 4.2V/cell is damaging to high-rate (15C+) lithium cells in particular
•
The potential for damage from over-volt charging increases with charge rate
•
Tests of other-brand chargers prove that many are poorly regulated, and that even some of the more expensive units
regularly overcharge batteries.
•
We can only be assured that Hyperion chargers will regulate properly (test one…)
•
TCS set to ~98% adds extra insurance when charging at high rates. Tests show slightly longer life when TCS is used
this way.
•
Therefore it was in our interest to specify 1C max until this time, as now we have the powerful 1210i charger with 2C
max rate, TCS, and Hyperion’s typically excellent voltage regulation.
Note: These are the C rates for which NO degradation was found in Hyperion Lithium Packs:
(Tested at 2.5, 2.75, 3.0C)
HP VX: 3.0C
HP CL 16C: 2.75C
HP CL 20C+: 3.0C
If 2C is Good… Why not 3C?
2C is the sensible limit for fast charging lithium polymer. Due to the CC/CV nature of the lithium charging process, the returns
from increasing charge rate diminish very quickly after 2C. That is, total charge time is only a couple minutes shorter at 3C
compared to 2C, yet charge rate has to increase 50% for that small gain. Given this, the risk/benefit equation lands squarely on
the side of 2C max rates. Additionally, Hyperion has a responsibility to protect the interests of our customers. Since many
batteries are not capable of charging reliably past 2C, chargers which do allow 3C charging are much more likely to cause
damage to batteries, or even accidents. It is simply too easy to make a mistake with the Charge Rate setting, and there are no
electronic safeguards which can be reliably employed against making such a mistake. Finally, most chargers that are
theoretically capable of 3C charging can only do so for relatively low-S, low-capacity packs, due to inadequate max power and/or
current capability. (see below for more on max power)
If using other than Hyperion lithium packs, consult your battery’s documentation for allowed C rates, before exceeding 1C charge
rates.
Charge Amps vs. Charge Watts
The EOS 1210i is rated for 12S, 10A, with power limit of 180W. These ratings
make it one of the most powerful battery chargers in the world today, and the
few competitors it does have typically cost two to four times as much.
However, please note that a 10A maximum does NOT mean that every battery
pack can be charged at 10A. The total power limit of 180W will determine
where the current limits lie at higher cell counts, and the 10A limit determines
total power output at low cell counts. The table at right assumes that the pack
is fully depleted at start of charge, and the capacities shown have been
rounded up/down slightly to make it easy to follow. Variations in pack type,
state of charge, wiring employed, or presence of balancer devices may all
impact on the observed charge rate initially, but will not affect total charge
time greatly in most cases.
The left column shows the lithium cell count in the pack. The middle column
shows the CAPACITY that can be charged at 1C per number of cells (S). The
right column is the same, but at 2C rate. Taking 6S packs as an example, you
could charge a pack of 7900mAh at 1C, or a pack with half that capacity -
3950mAh - at 2C. Either way, the charger will be putting out about 7.9A avg.
during the initial portion of the charge curve…
So, you can see that even with a single EOS 1210i, you can charge at 2C, or nearly 2C, for some large lithium packs. For
example, packs in the range of 4S~6S, 3700~5000mAh are typically used for models in the “engine” .40ci to .90ci range, or
their equivalent (lighter versions) in Electric, such as Hyperion Extra 260 40e or Super Chipmunk 70e…
You can even charge a 4000mAh 12S pack at 1C. However, if you need a high-S, high-capacity lithium pack AND want to
charge it in 27 to 40 minutes, the Hyperion system of two packs wired in series really becomes helpful. That allows you to
separate the packs for charging on two sets of EOS1210i chargers mated to separate EOS LBA10 balancers (see LBA10 manual
for details on two-charger setup), and charge each half at 2C, or very nearly 2C. And do remember that even 1.7C is a good deal
faster than charging at 1C; much of the speed benefit is in the rise from 1C to about 1.7C… Note that you can ignore “C”
calculations for all practical purposes. Just set the charger to “2C” rate, and it will automatically settle on the actual maximum
(lower) rate, if there are power constraints. As an aside, the 1210i Cooling Fan will turn on if needed. Don’t worry if it doesn’t!
LBA DATAPORT FEATURE
The DataPort is a 3-pin output which fits the option cable #HP-EOSLBA10-DPC. See the label to locate the DataPort on the right
side of your EOS charger. There are two main functions of the DataPort connection to LBA10 balance adapter:
*The LBA communicates with the charger, giving notification when balance charging is completed, or when an error is detected.
In both cases, the LBA tells the charger to shut down. This insures maximum safety, and saves the user from having to
manually push the charger STOP (enter) button to stop the charge-end or error tones. The lithium battery should be
disconnected from the LBA as soon as possible after charging is completed.
* The DataPort version EOS chargers, when connected to LBA10 balancer via cable #HP-EOSLBA10-DPC, allow the user to
monitor the individual voltages of each battery cell during the charge process. This is an important addition to pack diagnostics,
as one is able to see the exact balance status of the battery pack (or packs, when LBA10 is in NET mode).
