Generators

[Airabel]

We're getting ready to buy a Honda 2200i generator, mostly for home emergencies but also for camping. We have a 16' Sport with a single 83 amp/hour battery. Does anyone know approximately the length of time it takes to fully charge a single battery from say a 12.4 volt charge?
Thanks

[AirMiles]

Several items to consider here.

First, you don't want to completely charge a battery with a generator. You want to "Bulk" charge the battery to 80 or 90% (until bulk charging stops) and then turn off the generator when it starts the Absorption stage. It is not very efficient to completely charge a battery with a generator. To bulk charge a battery from 50% to 90% takes a few hours, to take the battery to 100% may take five more hours. Five hours of generator run time for that last 10% is not efficient.

Next, to bulk charge my 230AH battery bank with a PD4655 converter with a 14.4V "Bulk" stage stage typically takes four to five hours. Your single battery may only take about two hours.

Then, the next issue is to determine if your converter has a 14.4V "Bulk" stage. The stock converter in my 2017 only charged at 13.6V. Therefore I replaced my stock charger with a PD4655VL that has a 14.4V Bulk stage and a light that displays which stage its in, so I know when to stop generator charging after the efficient Bulk stage is complete.

[AirMiles]

Think of the stages of charging a battery as filling a beer mug. In the first stage (bulk stage) you quickly pour the beer until the head fills the mug. Then you slowly add beer (absorption stage) as the head turns to beer. And finally, you could add beer to the mug as it evaporates (float stage).

Bulk stage quickly puts a lot of beer into the mug and absorption stage only puts a trickle of beer into the mug. Bulk stage quickly puts a lot of Amps into the battery and absorption stage only puts a trickle of Amps into the battery.

[Msherw]

Originally Posted by AirMiles

Think of the stages of charging a battery as filling a beer mug. In the first stage (bulk stage) you quickly pour the beer until the head fills the mug. Then you slowly add beer (absorption stage) as the head turns to beer. And finally, you could add beer to the mug as it evaporates (float stage).

Bulk stage quickly puts a lot of beer into the mug and absorption stage only puts a trickle of beer into the mug. Bulk stage quickly puts a lot of Amps into the battery and absorption stage only puts a trickle of Amps into the battery.

Great analogy AirMiles. The only way I would use a genny to charge batteries is via the 120VAC input to the AS and the onboard system. A constant input of 13.2 with no absorption or float is likely to cause a good battery to fail prematurely.

[Bill M.]

No, I do not know. I plug my trailer into the generator and use the converter to charge the battery. Much simpler, faster, and I think better than fooling with the 12 volt generator output. The converter fast charges when the battery is low and then tapers as it gets charged. I do not think the battery will even charge at 12.4 volts. Certainly it will never fully charge. Charging voltages are in the 13-15 volt range and need to be tapered down as the battery charges.

I can put enough charge in my 2 100 amp batteries to be quite useful in about 3 hours using the generator. I do not think they get "totally" charged until I plug the trailer in overnight.

Nice generator, I expect. I have a 12 year old 2000 that still does a good job. But the 2200 is the one to buy now that they are out.

I have heard of people charging directly from the 12 volts on the generator but have never seen a clear reason for why they do it that way.

[AirMiles]

I believe the OP is asking how long it would take to charge an 84AH battery, resting at 12.4V, with a electric generator connected to the Airstream's shore power cord.

[Bill M.]

My mistake. My reading skills were not sufficient. I apologize.

I do not know how long to fully charge but 3 hours gives a significantly useful improvement in charge when you are boon docking.

Wish I could go back and delete answer above but cannot. I thought he meant that he was direct charging from the gen at 12.4 volts charge voltage.

[AirMiles]

No worries Bill, I made a mistake in my post above too that I can't fix. I said the PD4655 has a 14.4V Bulk stage. Actually, Bulking occurs until 14.4V is reached and then the absorption stage begins. My wife and I have an agreement to not nag each-other over "senior" moments. Sadly, there is no such agreement on the Internet. I didn't mean to nag, I just wanted to redirect this thread back to the original question.

[Airabel]

We currently recharge the single battery each day with an 80 watt solar panel. On a sunny summer day it takes about 5 hours to bring the battery back up to full charge. I was wanting the 2200i generator for cooler cloudy weather when days are shorter and the heater may have to be in use. Maybe use the microwave too. Just wondering about charging time for the generator.

[ROBERT CROSS]

It shouldn't take any longer than it does on shore power...ours is within 1/2hr, depending on SOC.

Bob
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