Main charge

The charger now indicates that the main charging has started.
Maximum charge current is now delivered from the charger and battery voltage increases.
The main charge ends when approximately 80% of the battery is charged.
The time it takes depends on the size of the charger and the battery.

A simple calculation gives the approximate time from 0 to 80% :
80% of battery size Ah x 1.2 (battery efficiency) divided by the charging current
Battery efficiency? Read more in Battery University.

Example 1:
A battery of 100Ah and a 10A charger gives:
(0.8 x 100 x 1.2) / 10 = about 10 hours

Example 2:
A battery of 100Ah and a 25A charger gives:
(0.8 x 100 x 1.2) / 25 = about 4 hours

The examples above show that the charging time to 80% decreases very effectively with a larger battery charger.

Topping charge

When the main charge is complete, the topping charge begins.
Here the battery is charged up to close to 100%
The charger must reduce the charging current and ensure that the voltage does not rise above the battery gassing threshold (read more about the gassing threshold in the Battery University).
If the battery is charged in at ambient above + 30 ° C or below + 15 ° C, the external temperature sensor sends data to the charger that correctly adjusts the charging voltage to the correct level.

The time it takes for the topping charge to be completed is determined by the recorded main charging process stored in the charger microcomputer.
When the set conditions are met, the topping charge ends and the battery has now reached close to 100% charge rate.
This time can vary, often between 3-6 hours.

Recondition charge

If you have set the Tystor charger for Recond charging, this charging starts now.
With increased voltage and low current, extended sulphate crystalline dissolves efficiently.


After the topping charge, the battery is analysed by the charger.
If the battery is not approved, the charger will interrupt and alarm by a red indicator.
This can happen with old hard-sulphated batteries.
Allow the battery to rest for one hour, then start a new recharge with recond charge activated.
Often, a battery can be “rescued” by repeating a few recond charging cycles.
Read more about this in the Battery University.

Maintenance charge

If the battery is approved in the analysis step, now the maintenance charge starts.
The charger supplies any connected consumers with power while lowering the charge voltage.
As the name says, this is a maintenance sequence of the battery.
Now the last 1-2% is filled up. At the same time, the charger compensates for the battery own self-discharge.
After this, the Tystor charger starts the equalization charge periodically as long as the charger is running.
Read more about this in the Battery University.
You do not need to power off the charger – all Tystor chargers can be connected for years and years.
This guarantees optimum battery life and a fully charged battery.

Charging in system with load