trickle charge from grid

[MazingerZ]

Hi, I'm new to the forum and recently plugged a 48v LiFePO4 to my hybrid inverter,

bad weather, set to SUB output and keeping "float" from grid, as unlikely to get solar to recharge the batter anytime soon.

it's asking almost 100w from grid to keep the battery afloat. Is it normal?

thanks anyone!!

 

[sunshine_eggo]

The inverter/charger itself consumes power. On battery, they're 40-50W per 3000W of output power. They tend to be a less on AC.

AC-DC charging is usually not particularly efficient. 85% is a pretty efficient charger. At low power, the efficiency will be even worse.

You should be able to multiply battery voltage * charge current and compare that to the grid draw. The grid draw is likely higher to also provide power to the inverter+inefficiency.

 

[Bud Martin]

What is the parameter of the charging current setting? There will be conversion loss to convert 100W of input power from utility to the charger output to the battery.

 

[MazingerZ]

What is the parameter of the charging current setting? There will be conversion loss to convert 100W of input power from utility to the charger output to the battery.

Thanks guys

Using watchpower software, It's dark, charging current says 0 A when I set the charging source priority at "solar first" or "utility and solar" (the battery stays around 54, the set float voltage, and the grid meter draws around 300W)- then i set charging to "solar only"and charging current says 1 A and the battery slowly goes down, and the meter buys 200w (my average night time need before having the battery).

It seems upside down to me but I'm still a layman on the matter...