400AH Lithium Batteries

[pinoy48]

I have a 2022 Thor Sanctuary with 400 Ah batteries. I found after a few outings on hot days my batteries can only run with the a/c on 3-4 hrs. especially here in Texas on summertime. My question is, has anybody thinking, planning or has done modification to increased their battery capacity? - i.e. lithionics batteries
THANKS.

[Chateau_Nomad]

If you're just adding more battery capacity to an existing install, it's as simple as adding additional batteries. That said, finding space in a van could be the biggest challenge.

If you're looking at Lithionics, cost must not be an issue? If you're trying to effectively run A/C from battery storage, plan on something over 1k Ah of storage. You might do with less... but if you're ONLY on battery power, you're going to have trade-offs.

[DavidEM]

Plus think about how you are going to recharge 1,000 amp hours of capacity for the second night with AC.

DAVID

[Chateau_Nomad]

Battery powered vehicles create range anxiety. Battery powered RV air conditioners create cooling anxiety. Two things will help... vast improvement in device efficiency, and vast improvement in energy storage density.

Baby steps are being made, but until a major breakthrough happens in both of those, it's more of the same struggle. Until then, you pick your battles and know your limits.

[Pete'sMH]

That’s why I like having a generator. The new generation of fuel injected induction models start instantly and are about the same loudness as the A/C. Onan produces them in their 2800W models for class B and had planned to introduce a 4000W model but it was delayed due to Covid. Apparently it is back on the development/production schedule.

[Chance]

Originally Posted by DavidEM

Plus think about how you are going to recharge 1,000 amp hours of capacity for the second night with AC.

DAVID

Yep, Devil’s in the details. Mostly on how system will be used. For some this system could work well, for others not at all.

Sounds like he’s asking about “hot days” in Texas during summertime which is far worse than cooling only at night when primarily traveling and touring.

For occasional nighttime boondocking in a rest area, Walmart or Cracker Barrel, I’d estimate 600 Ah should be enough to sleep comfortably in a well insulated small van. It’s even possible 400 Ah is enough if turning A/C on late in evening provided temperature is not set too cold.

Air conditioner will consume about 100 Ah per hour during day when running 100% loaded, but at night should cycle less than 50% based on my experience. After 1 or 2 AM my van’s A/C doesn’t run often, and it’s tiny by comparison. I’d likely be happy with 400 Ah system for most nights.

Cooling all day long at beach or somewhere hot and sunny would require charging batteries during the day multiple times even if he doubled capacity to 800 Ah. At that point he might as well bring along a portable generator for those occasions.

Sanctuary specs show 190 or 200 Watt solar which will provide about 30 minutes worth of A/C on average day, so not much help at all from solar. At least not to power air conditioner — pretty much useless for that.

Specs also show 170 Amp second alternator which should provide at least 100 Amps to battery when driving or fast idling. When only stopping overnight on long road trips, that should get battery back to 100% charged after a few hours of driving or touring around sites. However, for staying all day at the beach, the van’s engine would have to fast idle nearly 50% of time or more just to keep up. And that assumes every time engine starts that rooftop A/C is turned off so battery is charged at 100 Amps or faster. The numbers just don’t make sense to do that — you’d be idling all the time.

To make a system like this somewhat practical for daytime cooling requires an engine-driven alternator that can charge battery 4~5 times faster than A/C drains them. At least that way van’s engine can run for 30 minutes and buy another 2~2-1/2 hours of cooling. The only system I’m aware of that claims to do that is Volta with very high capacity 58-Volt alternator. And price is ridiculous in my opinion.

Bottom line — it’s a great concept that RV manufacturers can’t or won’t provide at a reasonable option price. It will likely take chassis OEM to provide a “Volta-like” system on steroids as part of a hybrid powertrain before we see practical generator-less motorhomes that can cool all day in summer.

A few days ago I saw an RV with a $35,000 lithium option on window sticker. That’s more than a Toyota Prius or some plug-in hybrids that have far greater power and charging capabilities. Pricing is insane for what’s provided. They are either technically inept and or greedy.


OK, that was my monthly rant on lacking technology
.

[DavidEM]

Very comprehensive expansion on my one liner above.

David

[robertj1961]

Originally Posted by Pete'sMH

That’s why I like having a generator. The new generation of fuel injected induction models start instantly and are about the same loudness as the A/C. Onan produces them in their 2800W models for class B and had planned to introduce a 4000W model but it was delayed due to Covid. Apparently it is back on the development/production schedule.

Totally agree regarding the generator. The Onan 2800QG 2800i is not much if any louder than the Air Conditioner and uses very little fuel from your existing gas tank. To install battery power to increase your capabilities for what you are looking for would be much more expensive than installing a generator. You can get a portable if you don't mind carrying it on a rack etc for much less than having one installed but the generator would probably solve your problem and not have to worry about additional battery power. At 400a/h you already have twice the battery capacity I have. Can run the Air Conditioner however indefinitely (or at least until the fuel runs out). The Onan cost is about $3600 and it can be installed underneath the van because Thor has already done this up until the 2023 models. I have had zero problems with the Onan and was very surprised how quiet it is. Generator technology is simple in comparison and without the worries of more technology needed to add that kind of battery power. Also agree that additional solar for what you are looking for would be like putting a band-aid on a severed carotid artery.

[Chance]

Originally Posted by robertj1961

Totally agree regarding the generator. The Onan 2800QG 2800i is not much if any louder than the Air Conditioner and uses very little fuel from your existing gas tank. …..cut…...

OP has 2022 Sanctuary, and most of them are on Mercedes diesel van chassis. If so, it would require a more expensive diesel generator, or a propane Onan 2500.

There are some Sanctuary on Ford Transit that run on gasoline. In those cases it’s probably easier to add a 2800i Onan than it is for a diesel Mercedes Sprinter.

[DavidEM]

Onan makes a propane fueled 2500i inverter generator.

David

[robertj1961]

Originally Posted by Chance

OP has 2022 Sanctuary, and most of them are on Mercedes diesel van chassis. If so, it would require a more expensive diesel generator, or a propane Onan 2500.

There are some Sanctuary on Ford Transit that run on gasoline. In those cases it’s probably easier to add a 2800i Onan than it is for a diesel Mercedes Sprinter.

Agreed and forgot about the diesel Mercedes chassis. David is correct about the Onan having a 2500 watt propane model however but I believe it is a little more expensive than the gas one but still in the same price range.

[Chance]

Originally Posted by robertj1961

Agreed and forgot about the diesel Mercedes chassis. David is correct about the Onan having a 2500 watt propane model however but I believe it is a little more expensive than the gas one but still in the same price range.

Yes, I was aware that 2500 is same inverter generator as 2800 (2800i) except engine is set up to run on propane instead of gasoline. That’s what causes slight power reduction. Onan hasn’t manufactured the non-inverter 2800/2500 for a couple of years as far as I know.

However, the reason I mentioned a propane generator at all was not due to whether it was inverter or not. I mentioned diesel for being significantly more expensive (and heavier and louder too than 2800i) and the propane 2500 because it runs on propane. To me that’s a deal breaker if planning to run generator often because it consumes a lot of propane (relatively speaking) and some vans have small propane tanks to start with. That’s the context for bringing up propane not being the same as gasoline generator, which takes fuel from gas tank.

I can’t find specs for Mercedes Sprinter Thor Santuary tank sizes but expect that it may have a relatively small propane tank. Granted generator would be used mostly in summer so not using as much propane for heat at same time.

One more point on this retro topic of adding a generator: Various manufacturers of diesel vans (and some larger motorhomes too) have done away with propane altogether by using diesel for water and space heat. In these cases you’d have to add a propane system for a propane generator, at which point it may be cheaper to just spend more on diesel generator — assuming there is space and weight capacity. Sanctuary should have propane tank, so just mentioning in case others are thinking of adding an Onan propane generator to a diesel van.

I’m a strong believer in buying the right RV to start with. Doing minor upgrades is one thing, but adding a generator will likely cost much more than if installed by manufacturer. Unless you can do install yourself, labor alone would be very costly.

[jannadem]

400 Ah battery means it will power max an appliance using 40A for 1 hour. 10A appliance will run 4 hours. I am sure that AC will need more than 10A. You can get consumption of an appliance from its sticker which shows power consumption in W (Wat). A = W / V. Example: consumption = 120 W, 12V battery A = 120W / 12V = 10A. Your battery capacity is 400 Ah. It will run h = Ah / A = 400Ah /10A = 40 hours

[16ACE27]

Originally Posted by jannadem

400 Ah battery means it will power max an appliance using 40A for 1 hour. 10A appliance will run 4 hours. I am sure that AC will need more than 10A. You can get consumption of an appliance from its sticker which shows power consumption in W (Wat). A = W / V. Example: consumption = 120 W, 12V battery A = 120W / 12V = 10A. Your battery capacity is 400 Ah. It will run h = Ah / A = 400Ah /10A = 40 hours

So confusing! You can't talk amps or amp-hours without including volts.

For example:

A 400 AH battery bank at 12 VDC will run a 10 amp 12 volt load for 40 hours.

A 400 AH battery bank at 12 VDC will run a 15 amp 120 volt air conditioning load for 2.67 hours.

[RonRM]

They said there would be no math!

[Chance]

Originally Posted by 16ACE27

So confusing! You can't talk amps or amp-hours without including volts.

For example:

A 400 AH battery bank at 12 VDC will run a 10 amp 12 volt load for 40 hours.

A 400 AH battery bank at 12 VDC will run a 15 amp 120 volt air conditioning load for 2.67 hours.

To keep it simple and straight forward, and avoid confusion, I believe it’s best to keep power numbers (in Watts) separate from battery ratings (in Amp-hours). Unless it’s specifically mentioned otherwise, 400 Ah is just that — regardless of voltage. What that 400 Ah can and can not accomplish obviously depends on voltages, but that’s a more complicated analysis involving other equipment because they are not 100% efficient, hence math is a bit more complicated. In this case it is implied an inverter would convert 12 VDC battery power to 120 VAC power required by an air conditioner, but that’s jumping the gun because more and more motorhomes are making use of both 12 and 48 VDC air conditioners.

Obviously 400 Ah of battery capacity at 48 VDC is a lot more energy than 400 Ah at 12 VDC, but both are still 400 Ah. That part of rating doesn’t change.

I’d stick to basics or confusion will be off the charts.


Without additional explanation, the number he listed are just wrong. And if goal is to power an inverter to then power an air conditioner, more information and calculations are needed.

[Chance]

P.S. — A rough estimate is that each 100 Amp-hours (at 12.8 VDC) of battery capacity (1,280 Watt-hours) powering an inverter at 90% efficiency, will be able to deliver 1,150 Watt-hours at 120 VAC to an air conditioner.

When using Power Saver or equivalent A/C, that is one hour’s worth of cooling. For van campers with efficient air conditioners, each 100 Ah of 12.8 VDC useable battery capacity should provide +/- one hour of cooling at rated A/C capacity.

[robertj1961]

Originally Posted by pinoy48

I have a 2022 Thor Sanctuary with 400 Ah batteries. I found after a few outings on hot days my batteries can only run with the a/c on 3-4 hrs. especially here in Texas on summertime. My question is, has anybody thinking, planning or has done modification to increased their battery capacity? - i.e. lithionics batteries
THANKS.

Wow...OP is nowhere to be found after asking a simple question about increasing run time for his Air Conditioner.

[16ACE27]

Originally Posted by robertj1961

Wow...OP is nowhere to be found after asking a simple question about increasing run time for his Air Conditioner.

He's been back to the Forum through all but today's posts in this thread. I assume he has reviewed the post. Just chose not to respond or participate in the thread he started.

[RizeMaster]

Originally Posted by Chance

To keep it simple and straight forward, and avoid confusion, I believe it’s best to keep power numbers (in Watts) separate from battery ratings (in Amp-hours). Unless it’s specifically mentioned otherwise, 400 Ah is just that — regardless of voltage. What that 400 Ah can and can not accomplish obviously depends on voltages, but that’s a more complicated analysis involving other equipment because they are not 100% efficient, hence math is a bit more complicated. In this case it is implied an inverter would convert 12 VDC battery power to 120 VAC power required by an air conditioner, but that’s jumping the gun because more and more motorhomes are making use of both 12 and 48 VDC air conditioners.

Obviously 400 Ah of battery capacity at 48 VDC is a lot more energy than 400 Ah at 12 VDC, but both are still 400 Ah. That part of rating doesn’t change.

I’d stick to basics or confusion will be off the charts.


Without additional explanation, the number he listed are just wrong. And if goal is to power an inverter to then power an air conditioner, more information and calculations are needed.

Wouldn't it be simpler to just use Watts and Watt-hours for this sort of stuff? That way, any differing voltage can be disregarded. For example, if you have four 1200Wh batteries, you can power an 1100W A/C for about 4 hours, no matter if it runs on 12, 24, 48 or 110V. Of course you have to consider inverter losses and such, but just a rough percentage will give an idea.


With A/C's (and fridges etc) cycling on and off this is a very rough estimate anyway, greatly affected by the ambient temp and how low you set the temp controller...