math formula?

[MsNomer]

And where this disparity really rares its ugly head is at the microwave.

Can somebody tell me they can drive that hour or so each day to charge their AGM batteries and still successfully use their microwave every day without voltage dropping to abysmal levels?

[booster]

Originally Posted by MsNomer

And where this disparity really rares its ugly head is at the microwave.

Can somebody tell me they can drive that hour or so each day to charge their AGM batteries and still successfully use their microwave every day without voltage dropping to abysmal levels?

Actually we could, but it takes a lot of battery capacity and being up above maybe 40% SOC for us. We have 440AH of Lifeline AGM and they will run the micro which takes 90-110 amps until about 40% SOC. We can fast charge up to 200+ amps from the twin alternators. A 15 minute microwave a day would be only about 25AH so we could recover that, within the 40% to 75% SOC range in about 10 minutes of run time. Voltage drop inverter cutout is all about the batteries type, brand, capacity, the inverter low voltage cutout setting.



Our system was designed to be able to do this, so it is not surprising it works fine that way, but it takes a lot of hardware. Your scenario is really quite easy for us to do, even with an hour of microwave run a day.

[MsNomer]

Ah, 450Ah. That oughta do it. My 250Ah would start complaining in a few days.

[GeorgeRa]

We use 600W (85A draw at 12V) microwave rarely but at 230Ah batteries watch SOC and recharging plan carefully. Mostly for cooking inside just use our Origo stove.

[Santiago]

Originally Posted by booster

Obviously, very few people drive that long on a regular basis so most batteries don't get full charges from the alternators.

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For best battery life, getting to true 100% every 10 cycles or so is needed, but rarely happens in RV use IMO.

Booster is correct.

That has been my experience with lead acid (AGM in my case). Quick bulk charge then takes forever and a day when absorption and float stages kicks in.

High charging rate amps coming in from alternator helps cut time to fully charged state. Maximize the rate if you can without exceeding battery charging capacity.

I had relationship with my local AGM dealer that mainly sold high end AGMs to harbor cruise operators. He did very well for the simple reason that the operators during course of the day did not have time to fully charge their AGMs between excursions. Prematurely replacing very expensive AGMs was cost of doing business. My dealer friend was happy.

As Booster stated, you need to fully charge into float on a regular basis, the more the better for long life.

Never going back to lead acid. With lithium charging is pedal to the metal (all bulk). My campers' alternator charging rate averages 100 amps depending on battery state of charge. No solar installed. On rare occasion will charge on outside power. Inverter set to 100 amp charge rate.

[habsfan59]

In my Roadtrek Ranger RT (2014) I have a 3CuFt Norcold (Model DE078 and the current draw is about 4Amp (12 VDC) wen the compressor is working.

https://www.westmarine.com/buy/norco...ezer--10899169

[ilmor]

my calculation is 2 or 3 hours always does it

[booster]

Originally Posted by ilmor

my calculation is 2 or 3 hours always does it

Does what? Data for what it does?