CTEK MXS 5.0 Faq page 10

With today's electricity prices, the cost is about .10 cents (USD) to charge a half-charged 75Ah
battery.
It is possible to calculate to 80% efficiency for all models of CTEK chargers.
Vary the battery sizes (Bs) and charging level (Bl) to calculate other examples.
What happens if I use the charger for batteries that are
larger than you recommend?
Charging with a smaller charger than recommended will take longer time and will not
optimally extend the battery life and performance.
Charging with a bigger charger than recommended will not result in a completely charged
battery and will not optimally extend the battery life and performance.
How deeply discharged can a battery be and still be
recharged by a CTEK charger?
Most CTEK 12V chargers can charge up batteries 2V. Our 6V charger can charge from 3V, and our 24V
chargers manage batteries from 4V. Chargers equipped with the "Supply" mode need no counter
voltage, and therefore can charge up batteries from 0V.
Can I charge GEL batteries with my CTEK charger?
GEL batteries are a type of lead/acid battery where the acid is bound in a gel. These
batteries can be charged with a CTEK charger with no problems whatsoever.
Can a frozen battery be charged?
No, the battery must be thawed first. Note that the battery was discharged first. Otherwise,
it would not have frozen. Check the battery carefully for cracks or other damage. A fully
charged battery freezes at -67 degrees Celsius, while a drained battery can freeze at just a
few degrees below zero. If you think your battery is or was frozen, we recommend that you
have the battery tested. It has probably been damaged and may have to be replaced.
Can I maintenance charge several batteries at the same
time?
CTEK chargers are fully capable of charging or maintenance charging several batteries
connected in parallel provided that the total size of the batteries (Ah) does not exceed the
recommended size for the charger. Remember to completely charge each battery
individually before connecting them. Otherwise, there is a risk of current surges between
that batteries that can cause unnecessary wear.
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