It would depend on what you have for an AC unit. I have twice the battery bank you do but still AGM and I can run my Mach 3 PS for a few hours along with a bunch of other stuff.First -- to answer questions that have been asked: The batteries are Concord Lifeline Model 31XT. I have 4 AGMs. To run air conditioning off the batteries probably requires 6 lithium batteries as they can be, I think, more deeply discharged without shorting life..
Are you sure they are only using the factory alternator for charging? I thought they had a second one installed on those. Even with something like the sterling alternator to battery charging unit I have on mine if they are using a higher draw roof unit that is not really a sustainable system with a 100% duty cycle on the AC. It only sort of works for me and I'm pulling more out of the alternator and plugging in every night.The two days at the factory were intense. Although I had pre-studied some manuals and although I am familiar with the Sprinters the learning curve for this old man was and still is steep. All the folks were fantastic and everyone who was needed was available for as much time as I needed. Mike (the "leader") and technical/production people of all skills were available to tutor me. No one minded if I asked the same question more than once. The item most difficult to master is the Silver Leaf computer/control touch screen system that runs everything. It controls and monitors (with alarms settable for all desired levels) things like batteries, tank levels, climate controls (air conditioning/heat) --- you name it, Silver Leaf runs it! Automatic water tank fill was an interesting feature. The neatest thing is the automatic engine start with advance to fast idle for running the 220 amp alternator. At the moment Mercedes is limiting that to 45 minutes at a time, but it can be repeated as necessary. Everything is interlocked via Silver Leaf. For example the engine will not auto start unless the tranny is in park and the parking brake is on. There are many minor systems to master such as outside motion detector photocell lights and six wheel tire monitoring system. The Espar heating/hot water system controlled by Silver Leaf takes some understanding as it is all automatic if desired, but one does not want to run the burner if shore power is available. The built-in shore power "surge protector" analyses the income power for stability for 2.5 minutes before completing the connection!
Something seems amiss,On my Advanced I can run the A/C for short periods from the batteries then refill them from the engine. I believe that all their RVs to date only use the single up-grade 220 amp alternator from Mercedes. Realistically my 4 AGMs seem to only be able to accept charge at a 90 amp rate when half discharged. Lithium batteries would be a huge advantage as they can be more deeply discharged and accept charge faster. They are an evolving technology and very expensive now. Advanced is exploring the possibility of a second alternator with auto engine start but all takes approval from Mercedes. Batteries can only accept charge at certain rates so big/second alternators are only good if the type and size of the batteries can accept high amp charging rates.
That charge rate actually sounds about right, but it's the alternator not the batteries limiting the charging at the that discharge level. With the boost mode off on my sterling unit total alternator output at 1200rpm is around 150 amps when my bank is around 75% unless something like the roof AC is running to really bring down the voltage the alternator is seeing. The basic sprinter setup with the dash AC running draws about 25 to 50amps with it being closer to 50 right after start up so you would need to subtract that from the total before it gets to your bank. I would also wonder what they used for wire to the bank as I'm betting it could be a little small to save money.Realistically my 4 AGMs seem to only be able to accept charge at a 90 amp rate when half discharged. Lithium batteries would be a huge advantage as they can be more deeply discharged and accept charge faster.
Makes sense.That charge rate actually sounds about right, but it's the alternator not the batteries limiting the charging at the that discharge level. With the boost mode off on my sterling unit total alternator output at 1200rpm is around 150 amps when my bank is around 75% unless something like the roof AC is running to really bring down the voltage the alternator is seeing. The basic sprinter setup with the dash AC running draws about 25 to 50amps with it being closer to 50 right after start up so you would need to subtract that from the total before it gets to your bank. I would also wonder what they used for wire to the bank as I'm betting it could be a little small to save money.
Maybe they should just install a sterling alternator to battery charger.I stopped by the Advanced factory today for some up-date tweeks to my knowledge of operating their computer. Re second generators or alternators on the engine: They are experimenting with these but not yet offering them. They are seeing some issues and want to overcome them. They want smart charging regulation but this is difficult at very high amperages.
So I guess the Advanced RV Sprinter B-van is a lot more expensive than the AS Interstate? Well north of $150,000?My wife and I went to see Mike and his team at Advanced RAV. I REALLY like what they are doing. BUT unfortunately we are limited on our budget and could not see fit to spend what Mike wants for their class and quality build. ....
We take delivery next week of our new 2014/2013 Airstream Interstate Extnd. chassis.
+!! This isn't really rocket science. Marine electrical system designers have been doing it for years. Hi-capacity battery banks and smart chargers capable of handling hi-amp alternators are commonplace on boats. It's been 20 years since I lived aboard a boat, and this stuff was available even then -- the state of the art has only improved over that period of time.Maybe they should just install a sterling alternator to battery charger.
Advanced RV have a couple of demo units advertised on their website, one of which is going for $143,792. Since they are really bespoke builders, I should imagine a decently equipped one would run at least $160K.So I guess the Advanced RV Sprinter B-van is a lot more expensive than the AS Interstate? Well north of $150,000?
Hi Diamondsea, I am in the market for a Sprinter conversion with a lot of extensive dry camping. Looks like a very well build luxury van in his own class but not sure where to start here. I thing no matter how big the battery bank, inverer or solar system is to run all night A/C probably any sort of generator is needed. Please advise what is your experience with that engine chassis alternator or you really need to have a second one?On my Advanced I can run the A/C for short periods from the batteries then refill them from the engine. I believe that all their RVs to date only use the single up-grade 220 amp alternator from Mercedes. Realistically my 4 AGMs seem to only be able to accept charge at a 90 amp rate when half discharged. Lithium batteries would be a huge advantage as they can be more deeply discharged and accept charge faster. They are an evolving technology and very expensive now. Advanced is exploring the possibility of a second alternator with auto engine start but all takes approval from Mercedes. Batteries can only accept charge at certain rates so big/second alternators are only good if the type and size of the batteries can accept high amp charging rates.