Charging agm batteries

[Sandiegodoug]

Just quick question. If my 2 agm batteries down to 50%, how long does running the propane generator take to get back to 100% assuming clouds and solar not producing well.
I have an isata 3. Also, any idea how much propane would be consumed if that was only load?

[bclemens]

I did a chart a while back on the LP vs. diesel gen and fuel usage. Onan has one...

Googling 3600 LP fuel usage, I yield this...
Fuel Consumption @ ½ Load 0.6 gal/hr

As for run time...really depends on the draws. You might be able to get it to 90% in a couple of hours...but that last 10% takes a long time, so I would not expect them to get to 100%. If you take a drive, the chassis will charge them as well. Sometimes people are more accepting of that than the gen running.

[Sandiegodoug]

Thanks for responding. We have had our isata 3 almost 3 years, and gen only has 2 hours on it, mainly use to put out slide, levelers . We were informed gen needs to be run much more so we figure use to charge batteries, get some hours on it, even though solar system seems to do good job. Does just charging use 1/2 load on gen.
Thanks, we dry camp a lot

[bclemens]

Not sure exactly what charging pulls on the gen....but that's all they chart. half load or full load.

[Coda]

Best time to exercise the generator is when it’s so hot outside the cab ac can’t keep up. Then running the generator with the AC on will load it up.

[docswisher]

Does the inverter also charge the chassis battery or just the two coach batteries?

[bclemens]

Originally Posted by docswisher

Does the inverter also charge the chassis battery or just the two coach batteries?

Well, since we are on a thread about the Isata 3, the inverter does not charger the chassis batteries, the converter does that.

On the Isata 5, and up, it is an Inverter/Charger so no converter and the inverter does in fact charger the house and chassis batteries.

On the Isata 3, that is just a stand alone inverter so the Converter has a charger built in that charges the house and chassis.

[TitanMike]

Originally Posted by bclemens

Not sure exactly what charging pulls on the gen....but that's all they chart. half load or full load.

Depending on converter size, at max output they only draw 1,000-1,500 watts and that's based on the "sticker rating" of the Converter. A converter alone will rarely reach the 50% loading of a 3500 W generator.

The longer any Lead Acid chemistry battery is charged the lower the current draw as current drops into absorption rate and tapers off until it finally switches to float.

Lithiums on the other hand will draw max output of the Converter until they are almost fully charged. Even at that a 60 amp Converter will only be drawing less than 900 watts which is less than 1/3 the output of a 3500W generator.

In short, if loading your generator is your goal, battery charging isn't that big a load. An A/C unit or space heater on High will do a far better job of loading.

[Sandiegodoug]

Another question. When my isata 3 is in storage, is the solar system charging both chassis and house. We get tons of sun . Also, I usually press disconnect button when in storage.

[Coda]

If it’s set up like the 2020 Isata 5. The solar only charges the coach and it will continue to charge the coach batteries even with them disconnected.

[babock]

Originally Posted by Coda

If it’s set up like the 2020 Isata 5. The solar only charges the coach and it will continue to charge the coach batteries even with them disconnected.

And that's always the way you want solar connected. If its between the disconnect switch and the coach, you would have power applied to the coach while the battery disconnect is off. This would allow very large voltages from the controller powering items in the coach when the sun is out. Also, you would have power applied if you were working on the electrical system in the coach.