House Batteries

I have the Magnum auto-start and the start voltage is adjustable but only up to 12.0 or 24.0 depending on witch voltage your running.

I know 12.2 is the magic # but that is a resting voltage and so if you drag them down to 12.0 under load that is IMO just right. Depending on size of the load 11.9 could be O/K and better if it is large load like a residential fridge.

When it goes on the run time is 3 hr, preset nonadjustable. It has a quiet time override and can be programed to cycle the gen on a timed sequence instead of a low voltage start. Finally you can wire the thermostat from one of the house a/c units to it and it will auto-start when that a/c calls for cool and again, run for 3 hrs.

I got it for 159 bucks from the cruise-air guys, they have them. I later found out they undercharged me by a couple hundred dollars, I believe they are around 350. Comes with a remote.

The Liberty autostart has the ability to autostart when low shore or gen voltages become evident, this unit will not do that.

Hopefully this is close to on topic....

With a good set of house batteries, how long can one expect to run a couple of A/C's for instance?

Maybe more appropriate, what can be expected in terms of background use for over night from a good set of batteries? One A/C and some lighting? No A/C's?

Although it is possible to run a/c off of inverters it is almost impossible to do it without the bus running or shore or gen power available and I do not believe it was the intent of designers to do so.

I would be surprised if you could get more than a couple of hours trying to power a/c off inverters w/o input power, along with all the other the essentials like the fridge and such.

Excluding a/c, even a weak set of batteries should be enough to get you 8 hrs overnight.

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Originally Posted by Joe Cannarozzi

Although it is possible to run a/c off of inverters it is almost impossible to do it without the bus running or shore or gen power available and I do not believe it was the intent of designers to do so.

I would be surprised if you could get more than a couple of hours trying to power a/c off inverters w/o input power, along with all the other the essentials like the fridge and such.

Excluding a/c, even a weak set of batteries should be enough to get you 8 hrs overnight.

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Thanks Joe - that makes sense certainly, but I was curious after reading different threads on inverter use during quiet times, etc.

A couple of comments....

On our previous coach, I could program the auto start through the inverter control to start at almost any set point that I wanted such as specific voltage or percentage of state of charge, and the options for the generator to shut down included manual, float charge, or a specific voltage. Very easy and user-friendly. I sure wish I had that same control in my Liberty.

Regarding the dry camping issue, we have never had a problem with the batteries lasting through the night, say 8 to 9 hours.

Actually, we've had them last through much of the day if we're away from the bus. Of course, with minimal loads. Usually, I would run the generator from about 3 or 4 in the afternoon until 9 or 10 at night. That seemed to be plenty to provide AC for cooking/cooling/etc. during the "busiest" part of the day and keep the batteries up the rest of the time.

If we stayed up later and watched TV for a while after the generator was shut down for the night, sometimes I will run the generator for a couple of hours first thing in the morning before leaving the bus.

I think that you should expect the batteries to easily make it through the night with light loads.

Unfortunately, I have no experience trying to run AC loads on battery power.

Gordon - Most of the Marathons will run 1 A/C for 4 to 5 hours or 2 A/C's for about 2 hours on the inverters. I had a 97 that I put in all new house batteries and I could easily get that usage. Keep in mind, those were 2 4,000 watt trace inverters and 6 4D AGM Lifelines. If you have a good set of batteries, like Paul said, overnight is no problem with conservative use of the power. Like the others, I run the gen for about 3 hours before bed and your good to go.

Brian - If money was no object like Jdub & Mango, I would for sure convert this Watchdog nightmare over to the Magnum's auto-start capabilities.

Joe - I don't know how you could call the 12.2 a resting voltage when dry camping. There is no battery resting in my dry camping, something is always calling for power. I do agree that 12.0 is probably an OK number and once again, it's all about cycles.:)

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Originally Posted by truk4u

Richard,

Here ya go, current work in progress... Jump in the car, come to Waleska and you can see them in person.;) Do yourself a favor and buy Lifelines with the POG discount. These junk Deka's only went 3 1/2 years.


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How do you go about getting the POG discount and do you know of dealers in the Southern California (Long Beach) area?

RB

Gordon,

We run one or two AC's all the time on the batteries and the time really depends on the temperature. I have had them run 2 or 3 hours before the generator started and I have had them run 8 hours. The big amp draw is the compressor is running, so if it only cycles on intermittently, then you get longer run times.

Richard,

If your doing the work yourself, just call Lifeline, tell them your a POG member and they will ship them to you. If you have the work done by some shop or dealer who also sells you the batteries, you will obviously pay more.
I thought you were near Atlanta according to your screen address, so I know you won't be visiting.:p

Thanks fellas - sounds like with good batteries you have some options for invertor only use overnight if conditions aren't too demanding.