Inverter versus 12v charging

[oldvarnish]

I have a piece of equipment which requires its battery to be re-charged now and again. It's quite a small battery, and if using an inverter the manufacturer says that an 80W inverter is sufficient - so it's not hungry.

Various leads (supplied) give me the option of charging it directly from the boat's 12V supply, or with a mains charger plugged into a small inverter.

These are my questions:

Will the battery charge faster via the inverter, or from the 12 v supply (when the boat engine is not running and assuming the batteries to be 90% charged))?

Is it more efficient to charge via the inverter or directly from the battery bank.

Please give you answer on one side of the paper only.

 

[bedouin]

The speed of charging will be more a factor of the device batteries rather than how it is supplied - so it should charge in the same period of time either way.

All other things being equal, efficiency should favour the simpler solution - namely the directly from 12V. With the inverter you are wasting power converting 12V DC into 240V AC only to convert it back into DC again - that additional stage is going to increase the losses although with the efficiency of modern circuits it shouldn't make much difference.

 

[elton]

It's always more efficient to charge from 12V rather than using an inverter.

I won't have anything on my boat that requires a 240V supply. There are always 12V alternatives.

Whether it charges faster on 240V vs 12V depends entirely upon the charger. Using the same charger, it's unlikely to make any difference.