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 > Does Generator wattage size effect battery charge time?

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brianosaur

Long Island

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Posted: 05/11/23 08:54am Link  |  Quote  |  Print  |  Notify Moderator

If I plug a RV shore power cable to a generator and let the onboard converter/distribution panel charge the batteries, is the generator size irrelevant to charge rate/time?

dougrainer

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Posted: 05/11/23 09:19am Link  |  Quote  |  Print  |  Notify Moderator

Yes. Doug

time2roll

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Posted: 05/11/23 09:51am Link  |  Quote  |  Print  |  Notify Moderator

As long as the generator meets the minimum power necessary to drive the converter it will charge at maximum speed.

Too small and the generator will overload and give nothing.

For best answers on fast charging... post the battery and converter details.


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pianotuna

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Posted: 05/11/23 11:20am Link  |  Quote  |  Print  |  Notify Moderator

very few converters draw more than 1200 watts. So any time there is a 15 amp supply speed of charging is not affected.

As time2roll said--post the make and model of the charger.

My OEM PD unit charged at about 30 amps.

The Magnum inverter/charger 3012 allows for up to 127 amps (15 amps total shore or generator power @ 120 volts.)


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ktmrfs

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Posted: 05/11/23 12:58pm Link  |  Quote  |  Print  |  Notify Moderator

yes or no are the answers it depends

No as long as the gnerator can supply the continous VA needed by the converter.

Yes,

if it can't at least on a deeply discharged battery bulk charging current may be high enough to trip the overload on the generator.

Now most 2000 VA generators will drive most commonly installed chargers. Those rated at 30-50A.

And just because it works ok when your battery is partially discharged doesn't mean it will be fine with a deeply discharged battery bank. Current draw by the converter depends on how deeply discharged the battery is.
In my case the answer is depends. I have 2 PD in parallel, a 50A and a 60A, the 60A is the max my honda 2200 can handle. If I have shore power or my generators paralleled I turn on both Chargers and can dump 100A into my battery ban for initial charge (4 GC2's) Each has a seperate circuit so it's easy to flip whichever breaker(s) I want.

One isue with most chargers is the watts<< volt amp draw. They have a very poor power factor so the max current is higher than given by a watts calculation.


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brianosaur

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Posted: 05/12/23 06:59am Link  |  Quote  |  Print  |  Notify Moderator

Thank you for all the input[emoticon].

I have two inverter generators. A Honda 2200 watt (red suitcase) and a WEN 3800 Watt. I have used both to charge the batteries. (2x6v)

My TT is setup for 30a and the 3 stage panel states:

Panel Input 120v 60hz 30a
Converter Input: 105-130v 60hz 12a

So I assume 12a input means 12a x 120v = 1440w min size generator?

KD4UPL

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Posted: 05/12/23 07:44am Link  |  Quote  |  Print  |  Notify Moderator

I believe your math is correct. Either generator should be capable of powering your converter to it's maximum output. You would have to consider what over AC loads were on at the same time to stay withing the generator's rating.
I believe the Honda rating of 2200 is the surge rating and it's continuous rating is actually 2,000. The WEN is probably rated on it's surge as well. I don't know it's continuous rating.

time2roll

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Posted: 05/12/23 10:42am Link  |  Quote  |  Print  |  Notify Moderator

May need 20% to 30% additional apparent power as most converters have poor power factor.
Either listed generator will run the converter alone just fine.

No mention of the converter brand... however if the battery voltage never gets to 14.2+ volts it will be a slow charge to 100%. Could take 8+ hours from low to near full charging at a common 13.6 volts. Monitor the battery voltage to know what the system is actually doing when a fast charge is expected.

ScottG

Bothell Wa.

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Posted: 05/12/23 12:20pm Link  |  Quote  |  Print  |  Notify Moderator

It is irrelevant. As long as the gen is big enough to run the converter it wont matter if the gen is 2000 watts or 15000+.

brianosaur

Long Island

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Posted: 05/12/23 07:02pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:


No mention of the converter brand... however if the battery voltage never gets to 14.2+ volts it will be a slow charge to 100%. Could take 8+ hours from low to near full charging at a common 13.6 volts.


It is a WFCO WF8955PEC
The manual has some weird statement saying it reaches 14.4v but a multimeter will only show 13.6v

“If the output current reaches its maximum (normally caused by a discharged battery),
this will cause the converter to go into Bulk Mode, which means the target output voltage
will change to 14.4 VDC and a timer will start. Although the converter is outputting 14.4
VDC, you will not be able to read that on a voltmeter due to the voltage-current
relationship.“


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