How long to charge Batteries with Generator?

[Delboyarapaho]

I don't want to get into the controversy over the rights and wrongs of generators (please don't bite you anti Gen folk) but can anyone who has a Genny advise please how long a Honda 2KW generator would need to be run to top up batteries from say 12.4v to fully charged? I haven't bought one yet but am considering doing so but want to know if it is a practical proposition?

 

[Jimbohorlicks]

how long a Honda 2KW generator would need to be run to top up batteries from say 12.4v to fully charged?

About a mile away.

 

[Lenny HB]

Same time it would take if you were on EHU.
Can't say much more as you haven't told us your charger output or the size & type of battery bank.

 

[Delboyarapaho]

Same time it would take if you were on EHU.
Can't say much more as you haven't told us your charger output or the size & type of battery bank.

Sorry realised that after I posted. two 110 leisure batteries plus 90is vehicle battery. Don't know the charger output sorry but I have a Burstner elegance if that helps Lenny

 

[Lenny HB]

Sorry realised that after I posted. two 110 leisure batteries plus 90is vehicle battery. Don't know the charger output sorry but I have a Burstner elegance if that helps Lenny

What type of leisure batteries?
Was the second battery a factory fit?

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[Delboyarapaho]

What type of leisure batteries?

AGMs

 

[two]

Same time it would take if you were on EHU.

... is the correct answer.

 

[Lenny HB]

AGMs

Deepest condolences.

Was the second one factory fitted as if so they will have fitted a suplementry charger doubling the charging rate.

Also if the batteries are over a year old they will probably have lost a lot of their capacity AGM's do not fair well in Motorhome use.

 

[Delboyarapaho]

... is the correct answer.

Many thanks

 

[autorouter]

If you want to reduce the generator run time to a minimum, you can get a charger that will charge the batteries at their maximum acceptable rate. The rule of thumb is to take the Ah capacity and divide by 5. So for 220Ah of battery that's a maximum rate of 44 amps.

If the batteries were at 50%, it would take 110Ah of charge to refill them. At 44A that's 110/44 = 2.5 hours. In practice that would be 3.5 to 4 hours.

A single built-in mains charger is likely to be 18 to 20A. If there's an extra one fitted, double it.

So it's worth getting the extra charger fitted, to reduce the generator run time.

Lithium batteries will usually take a much higher charge rate than lead-acid types, so will charge much faster if you get a suitable charger.

Note that 44 amps at 12 volts is only 528 watts, so a generator smaller than your 2kW one will be OK.

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[wigster]

I have B680 hymer with built in genny as has been said same as on hook up , ie it provides the maximum amps that the charger can use as if on hook up .

It came in handy at the falls of shin car park one year when 3 vans were low on lecci , hook ups to the genni all round , funny nobody moaned about the noise

 

[Delboyarapaho]

If you want to reduce the generator run time to a minimum, you can get a charger that will charge the batteries at their maximum acceptable rate. The rule of thumb is to take the Ah capacity and divide by 5. So for 220Ah of battery that's a maximum rate of 44 amps.

If the batteries were at 50%, it would take 110Ah of charge to refill them. At 44A that's 110/44 = 2.5 hours. In practice that would be 3.5 to 4 hours.

A single built-in mains charger is likely to be 18 to 20A. If there's an extra one fitted, double it.

So it's worth getting the extra charger fitted, to reduce the generator run time.

Lithium batteries will usually take a much higher charge rate than lead-acid types, so will charge much faster if you get a suitable charger.

Note that 44 amps at 12 volts is only 528 watts, so a generator smaller than your 2kW one will be OK.

Really helpful explanation thanks