I am using an Outback fx3624 in just this way, and yes it's a lot faster. I actually only use it for a few weeks in the dead of winter when snow and clouds reduce the already short solar day to PV poverty. Then I only use it every few days for a few hours. Maybe if I stopped being lazy and put up my wind generator I could avoid even that.
My generator (also 5kw rated) has 20 amp breakers, so I can't supply more than 20 amps anyway, and that includes what I'm using while it's charging the battery. So I usually set it to provide about 16 amps for charging.
Your calculations will have to take into account the settings in the charger. A decent charger will allow you to specify things like the type and size of battery, high (bulk) voltage settings, temperature sensor (or not) and so on. This will prevent overcharging the batteries.
Every charger has an algorithm (Outback has a 5 stage charging algorithm) which limits the input depending on time and the voltage at the battery. So you may be putting 16 amps in for 10 minutes. It then ramps down to float voltage, where it stays or possibly drops down, while you waste gas, until it hits a set point and then charges up to bulk again, etc. You could be idling for hours.
I usually run it for a few hours to make sure I'm at float and turn off the generator. Most decent chargers have LCD panels that will tell you the voltage and amperage going into the batteries. If it's extra, pay the money. It's worth it. The temperature sensor too.
[ Parent ]
