Estimating Charge Time; High Internal Resistance - Victron energy Blue Smart IP65 12/4 Manual

3.4 Triggering a new charge cycle
A new charge cycle will start when:
a) The charger has reached float or storage, and, due to a
load, current increases up to maximum current during more
than four seconds.
b) The MODE button is pressed during charging.
c) The AC supply has been disconnected and reconnected.

3.5 Estimating charge time

A lead-acid battery is about 80% charged at the beginning of the
absorption period.
The time T to 80% charged can be calculated as follows:
T = Ah / I
Where:
I is the charge current (= charger output minus load current).
Ah is the amount of Ah to be charged.
A full absorption period of up to 8 hours is needed to charge the
battery to 100%.
Example:
Charge time to 80% of a fully discharged 100Ah battery when
charged with a 10A Blue Smart Charger: T = 100 / 10 = 10 hours
Charge time to 100%: 10 + 8 = 18 hours.
A Li-ion battery is more than 95% charged at the beginning of the
absorption period, and reaches 100% charge after approximately
30 minutes absorption charge.

3.6 High internal resistance

When a battery reaches the end of its cycle- or float life, or when
it dies prematurely due to sulfation or corrosion, capacity will
dramatically drop and internal resistance will increase. The
charger will not recognise such a battery during the test phase (it
could as well be a nearly fully charged battery).
A very short bulk phase when charging a supposedly discharged
battery does however indicate that the battery has reached the
end of its useful life.
Remark: sulfation can sometimes be partially reversed by
repeated application of the RECONDITION MODE.
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