Battery Chargers

[SpiceIslander1]

Could somebody out there with some electrical knowledge answer the following for me.
I currently have a 25 amp LEAB battery charger, and having recently upgraded my battery bank to 400 amp hours I was considering changing the charger to a 50 amp version.
However, I am also considering purchasing a Honda EU20i generator and I understand the output from this generator is rated at 7 amps DC and 8 amps AC. Does this mean that if I connect the generator by DC lead directly to the batteries it will charge them up at a max of 8amps/hour and if I were to connect the AC output side of the generator into my cockpit mains socket (Shore link up socket) then the maximum charge rate passing through the boat's battery charger will be 7 amps/hour(rated A/C output)?
If this is so it hardly seems worthwhile changing the battery charger, or is my thinking adrift here as the main reason for upgrading it was to use the generator whilst at anchor to charge the batteries at a much higher rate.
Perhaps somebody could confirm my thinking or tell me where I am going wrong.

 

[rickp]

Presumably the "8 amps AC" is at 240volts, thus 1920watts, whereas the "7 amps DC" is at 12 volts - so 84 watts.

Your AC battery charge will have plenty of power available from the genny to kick out 25 or 40 amps into the batteries.

Rick

 

[VicS]

The Honda will supply a maximum of 7amps (or is it 8amps) at 12volts BUT I cannot find any statement that this is for charging 12 volt batteries as that will require rather more than 12volts, something of the order of 14 volts. Other small Hondas have that DC output described as for battery charging. Rather doubtful about this as a result.

However the 230volt AC output which is rated at 2000watts max or 1600watts continuous should , if Hondas claims about its suitability to power sensitive electronics are correct, power your 25 amp LEAB charger or even the 50 amp version.

Spec for EU20i Here

 

[Achilles]

VicS is correct. I have the EU20i and use the 240v AC outlet to run a 40amp charger and heat a calorifier simultaneously. Does both easily.

 

[VicS]

[ QUOTE ]
VicS is correct

[/ QUOTE ] but wrong about saying that the 12volt output of other small Hondas is decribed as for battery charging!

Getting muddled with another make!

 

[roly_voya]

Used to run a 40a charger of a 750w 2st geny no problems so you should be fine with the honda but whether it is worth the cost of going to the bigger charger depends on your alternator. If you have 80a + alternator might be worth using main engine for bulk charge, if needed by fitting alt regulator as a 400a bank should easily absorb 80-100a when below about 75% charged. Once rate drops to about 25a change to the genset to finish off.

 

[SpiceIslander1]

Thanks to all for the very helpful comments.