Battery charger / charge time

[103Alex1]

Received this charger from BMS to go with 20Ah battery. What's the likely time to charge using this ?

Going to be charging in an outbuilding attached to a thatched property and in all likelihood left overnight, so want to make very sure that fire hazard risk is very low and also that it isn't a problem if the battery is left on charge to go to 'trickle' or 'green' once done as highly unlikely I'm going to remember to go switch it off on occasion ... the in-built fan did get me a little worried what would happen if that failed because the charger for my Kalkhoff battery is silent.

 

[Geebee]

How about plugging it into a timer socket, they are nice and cheap these days set it for 5 hours for peace of mind.
It says it a 4 amp charger so for a totally discharged battery say 5~6 hours in theory, in practice it probably won't be anywhere near empty so maybe a few hours.
Most chargers charge at their rated current until close to full charge and then the charge rate drops thus extending the time .

Fan failure will depend on ambient temperature and charger design, in England you would probably be ok if you just check the fan starts before leaving it. This assumes England is as cold over night as I imagine.

 

[Deleted member 4366]

It's a 4amp charger, so if your battery was flat (not very likely), it would take 5 hours to charge. It's fully automatic, so you can plug it in, switch on and go to bed, which is what I often do; however, it would be safer to charge when you're awake, so a mains timer is a good idea. You don't have to charge it all at once. Yoy could do a couple of hours in the evening, switch off, and finish in the morning. The only reason I leave mine charging overnight is because I forget or fall asleep, but, until now, it hasn't done any harm.

 

[NRG]

I never leave mine unattended, I don't trust some of the Chinease made charger units. I just recieved a recal notice for a Chinease charger used for a precision LCR meter as it is a 'fire hazard'. I would use a mains timer and always be around whilst it's charging.