Backup solution for charging the battery

DIY
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1

Hello, for a small photovoltaic installation, I’m looking for a backup solution for charging the battery (Pylontech US5000 - Lithium 4.8kWh - 48V).
I’m hesitating between an AC/230V generator connected to a Victron Multiplus 500VA 48V 6A and a DC/48V generator (KS 48V-DC from Konner-Sohnen) connected directly to the battery.
The first option has the advantage of being economical, but charging may be slow with a 6A charger and may also be unreliable depending on the model chosen.
How can I calculate an estimate of the battery charging time with each generator?
Thank you.

2

A 4.8kWh battery at 48V is about 100Ah so with the multiplus it would take about 17h to charge from 0% to 100%. A DC generator will probably be faster.

3

Thanks :slight_smile: So, in theory, if charging time (hours) = Battery capacity (Ah) / Charging current (A), then a 60A generator will charge a 100AH battery from 0% to 100% in less than two hours. Very efficient!
Out of curiosity, I’ll ask the manufacturer.