Advancing Alvar

[gregmchugh]

I don't see the need to bring a cold soaked unpowered camper van up to normal operational condition without needing an external power source as an unusual requirement. Starting the van engine in this scenario is a normal requirement for the stock van. How long is reasonable length of time to get the camper systems fully operational? Who knows, Since this is new territory in terms of the technology, owners are likely to be accepting of the need to take what may seem like an unusually long time to warm up the battery pack.

[Davydd]

Taking avanti's analysis, idling the engine 6.7 hours is not an acceptable solution. That's beating a dead horse.

In regard to heating pads, I do have the center aisle floor heating pad. That one could very well be 120vac as just about all that I can find are such that look like this that roll out on the floor for residential construction. This is an Alvar production photo.



I haven't found the battery heating pads or anything that looks like them. They are similar thin material and I measured them at 6-1/2" x 14". Small heating pads can be 120v or 12v it seems.

[wincrasher]

In my Oliver, we installed both 12v and 110v heating pads for my tanks. They come in both flavors. Our thinking was that normally we'd run the pads on 110v at park. When travelling, we'd run on 12v, with batteries charged by solar and the trucks alternator.

[avanti]

Originally Posted by Davydd

Taking avanti's analysis, idling the engine 6.7 hours is not an acceptable solution. That's beating a dead horse.

Not dead yet:
We are talking about 10 amps for that 6.7 hours--a mere 67ah. A few short recharges using the famous "autostart" feature would make this perfectly practical, even from the starter battery. And of course, one could easily set things up so that the Nations alternator could power MUCH more powerful heaters, so you could reduce that time to much shorter periods. A simple high-current relay could divert the charging current from the battery to the heater.

This is really quite trivial from a technical perspective. It is just silly to question feasibility. ARV should do this, and I bet they will.

In any event, I was thinking more about plug-in, where all these constraints just go away. If it were really -5F, plugging in for 7 hours seems perfectly reasonable. Yes, I know you would just leave yours plugged in. I would not.

And remember, this is an extreme temperature example. More reasonable scenarios give us 2-3 hours.

[Jostalli]

Originally Posted by Davydd

In regard to heating pads, I do have the center aisle floor heating pad. That one could very well be 120vac as just about all that I can find are such that look like this that roll out on the floor for residential construction. This is an Alvar production photo.



.

That looks like residential 120v radiant floor heating. The only one I found that is low voltage is the Warmfloor, which is what I have installed. It's 24V.

[mojoman]

Under load, the batteries generate heat. Anyone try to calculate the BTU generation of the batteries under load? I had a lithium battery in my motorcycle, in the winter the starter would turn over slow for the first couple of tries until the battery heated itself up under load.

[booster]

I don't think I would worry about the time needed to recover, as it could be adjusted by adding heaters. Nothing says you have to run all the heaters all the time, so you could easily have the 10 amps (120 watts) of heat when on normal use mode, and much more than that when in recovery mode.

[gregmchugh]

In my mind, the battery heater feature should not require shore power, the scenarios I can imagine would not have power available. As noted already, the time it requires is easily adjusted by sizing the heating pads to the correct wattage needed for the temperature rise and the time period.

[Davydd]

Originally Posted by mojoman

Under load, the batteries generate heat. Anyone try to calculate the BTU generation of the batteries under load? I had a lithium battery in my motorcycle, in the winter the starter would turn over slow for the first couple of tries until the battery heated itself up under load.

My general observation has been my battery bank can be anywhere from about 6 degrees to 20 degrees warmer than ambient temperature. Sitting with little load it would be closer to 6 degrees. That would be about a 3 amp draw with inverter and refrigerator off. When it receives a charge it heats up. When being used it heats up.

[Davydd]

Originally Posted by booster

I don't think I would worry about the time needed to recover, as it could be adjusted by adding heaters. Nothing says you have to run all the heaters all the time, so you could easily have the 10 amps (120 watts) of heat when on normal use mode, and much more than that when in recovery mode.

There are two heating pads, one each between two sets of batteries. They are not on all the time. In fact with the temperature around 20 deg. they will be off more than on. The pads apply heat to keep the temperature in the mid 40s range.

[Davydd]

When I say using the engine is a dead horse it is not a matter of time it is a matter of practicality.

1. It would have nothing to do with Autogen. Autogen is designed to come on to charge batteries and has a limited programmed runtime. Starting would have to be independent of that and a deliberate act at a deliberate time to accomplish a task. Simply starting with the key would be the act. There would be no need to do so when in prolonged cold storage.

2. Time is not the factor but that 6.7 hours example was certainly a non-starter dissuasion of the idea. When it is -5 degrees I am not going to start the engine and walk away and I am certainly not going to hang around in the cold weather to monitor.

3. I mentioned the many worrywort agonizers about the idea of idling a Sprinter already. Mercedes Benz' recommendation is idling is OK but you should drive it between bouts of about 2 hours of idling. I can live with that without too much handwringing and it is OK for battery charging. Runtime seems a big enough concern that Mercedes Benz, Roadtrek and Advanced RV have put in built in limits.

So when I say dead horse it would seem applying 120v heating pads simply by plugging in would be a far more elegant solution. Like I mentioned earlier, I may be wrong about 12v and maybe I can heat the batteries plugged in while they are disconnected already. That I have to test. When I originally did it, it never occurred to me. I've since learned a bit more. But even if not so, there is a very simple modification there.

But getting back to intent. There is failsafe factors built in for everything but cold storage and taking the B out of storage while the temperatures are still below freezing. If you routinely drive in the winter and keep your batteries charged it all takes care of itself no different than being able to live off grid 100% of the time if one chooses. If you plug in just to a 15a service problem is solved. If you leave in cold storage for the winter I would surmise 90%+ of the time you would not take it out of cold storage until such time you de-winterize and the batteries would naturally warm back up. If you intend to use your B in the winter as I plan (Tahquamenon Falls in January and head south in February) then one should have the common sense to plan ahead. Then there are the other solutions I mentioned. I think worrying about this is making a mountain out of a mole hill. Adding cost to cover something that can readily be solved and may never happen is not a big worry. To me it is no different than making a decision not to carry a spare tire. If it happens there are many ways to deal with it and one may never have to deal with it. 10 years and knocking on wood on the spare tire. I liked those odds and the 10 years of derived benefit.

This is not an end of the world deal. With your batteries disconnected you just have a short time inconvenience or steel tent without electricity. You can still drive your B.

[gregmchugh]

The scenarios I would envision would be leaving the van unpowered for days at a time while doing some other activity out in the wild (overnight wilderness skiing, snowshoeing, etc) or in airport parking for a week. No source of shore power readily available and needing to get the van completely operational. I suppose one could argue that you could leave it on solar power while away with no auto start enabled and the batteries would be kept up to temperature without draining them completely and that might be a viable option if there was enough solar power available at the time. Again, the time it takes to bring the batteries up to temp with the engine running and possibly driving could be adjusted by using the appropriate wattage heating pads.

[booster]

Originally Posted by Davydd

This is not an end of the world deal. With your batteries disconnected you just have a short time inconvenience or steel tent without electricity. You can still drive your B.

Sounds like a compromise to me

I think you would have a much better chance of selling that theory if, in the past, you hadn't said the ARV was a "no compromise" rig, and chastised the rest of us for "making excuses" for accepting compromises on our setups, that you wouldn't make.

I think we all have compromises we have had to make in how we setup and use our vans, and there is absolutely nothing wrong with that. You just call it what it is, and as long as it is good for you, nobody else gets a vote on it, so you shouldn't have to make "excuses". Explanations of why and how you made the choice can be useful for all, but it is your choice to make. Welcome to our world.

[gregmchugh]

There is a question I have on how the ARV system handles the case where the batteries are depleted to the point where the BMS takes them offline and the van power shuts down. What steps do you take to bring things back to normal. David mentioned a manual switch that is held down for some length of time to boot the system into operation. Are the batteries then online for some period of time before the BMS takes them offline again due to the being at the minimum allowed state of charge? Do you start the van engine before the reboot to insure that the batteries start charging when they come back online? The aux generator would need to sense the battery voltage to start charging so the van engine would need to be running when the batteries come on line before they get discounted again. Is Solar standard on the ARV or optional? I guess the solar, if available, would start the charging when the batteries came online and as long as the loads were small enough you could keep the batteries online until starting the engine.

[Davydd]

Originally Posted by gregmchugh

The scenarios I would envision would be leaving the van unpowered for days at a time while doing some other activity out in the wild (overnight wilderness skiing, snowshoeing, etc) or in airport parking for a week. No source of shore power readily available and needing to get the van completely operational. I suppose one could argue that you could leave it on solar power while away with no auto start enabled and the batteries would be kept up to temperature without draining them completely and that might be a viable option if there was enough solar power available at the time. Again, the time it takes to bring the batteries up to temp with the engine running and possibly driving could be adjusted by using the appropriate wattage heating pads.

Overnight is no problem. Three days is no problem for that matter. A week? That might be stretching it but Autogen would take care of it. Besides, parking it a week at an airport? Never going to happen with me and that is kind of a stretch what if. But what if? Simple, drive home and take care of the situation.

My experience with solar, BTW, in the winter is disappointing. With driving as much as I do and having 800ah of battery it is something I could probably do without. I haven't even used the Autogen for that matter.

This is not an end of the world catastrophic situation. I think I will build a heated garage like Booster. Right now snow on my B parked outside is a bigger pain in the ass than this.

Originally Posted by booster

Sounds like a compromise to me

I think you would have a much better chance of selling that theory if, in the past, you hadn't said the ARV was a "no compromise" rig, and chastised the rest of us for "making excuses" for accepting compromises on our setups, that you wouldn't make.

I think we all have compromises we have had to make in how we setup and use our vans, and there is absolutely nothing wrong with that. You just call it what it is, and as long as it is good for you, nobody else gets a vote on it, so you shouldn't have to make "excuses". Explanations of why and how you made the choice can be useful for all, but it is your choice to make. Welcome to our world.

Compromise? Yes, if you think it is a normal everyday need. It is not. It does not affect my everyday use. It is not a compromise in that it may never happen and I seriously doubt anyone of you has ever encountered a situation with your Bs where it could have happened had you known the parameters ahead of time. If I had your heated garage it would be a total non-factor. All I have been talking about is a bit of common sense and you guys have been Chicken Littleling yourselves beating this to death. If this is the best you have for a come back to gloat about what I have said then I am doing OK.

BTW, just confirmed. The radiant floor electric heating runs off the 120v side. Battery heaters run off the 12v side.

[Davydd]

Originally Posted by gregmchugh

There is a question I have on how the ARV system handles the case where the batteries are depleted to the point where the BMS takes them offline and the van power shuts down. What steps do you take to bring things back to normal. David mentioned a manual switch that is held down for some length of time to boot the system into operation. Are the batteries then online for some period of time before the BMS takes them offline again due to the being at the minimum allowed state of charge? Do you start the van engine before the reboot to insure that the batteries start charging when they come back online? The aux generator would need to sense the battery voltage to start charging so the van engine would need to be running when the batteries come on line before they get discounted again. Is Solar standard on the ARV or optional? I guess the solar, if available, would start the charging when the batteries came online and as long as the loads were small enough you could keep the batteries online until starting the engine.

Solar is an option. I've seen numerous different configuration as few are alike. However, I don't recall any ARV without solar. Solar to me basically cancels out your refrigerator use, parasitic, inverter, and other always on 12v stuff and then only in optimum conditions (sun, summer, orientation, high noon and no shade). Low angle winter short days I find it almost insignificant. Driving in the open the alternator is contributing way more and a day's use of electricity always tops off in less than an hour.

First, in theory if you have Autogen turned on your batteries should never run down to the preset cutoff of 20% ARV uses. On top of that I have my Autogen programmed to come on at 30% Still, I never invoked it because of battery depletion. I have by testing. There is a lot of safety factor built in. I'm not sure how Roadtrek does theirs. They say 10% and then Voltstart comes on. They don't say if Voltstart is programmable, is able to be turned off or what a procedure would be if the batteries depleted.

I did deliberately run my batteries down by turning off Autogen and turning on everything I could to deplete the battery. To get to that point I had to let it sit in my driveway for three days and then turn on everything so I could be there the moment it happened. It can be like watching paint dry. When it depleted 640ah it all shut down. To bring it back online you can either start your engine or plug into shore power. Then you have to manually hold down the top half of the battery disconnect toggle switch for approximately 6 minutes and that force charges the batteries and that is approximately 1% of charge or up to 21%. As you can imagine since you have to manually hold a toggle switch down it would take forever with solar. 6 minutes is agonizingly a long time. Silverleaf then comes back to life. After you recover you then just continue to charge be it by idling the engine, being plugged into shore power or driving. High idle via Autogen is going to run a programmed, in my case, 110 minutes, which means I would restore about a usable 400ah. Driving will top off the battery in under 3 hours. Plugged into shore power would take about 6 hours. I'm working with a usable 640ah of an 800ah battery. 160ah or 20% are in that unusable reserve.

[gregmchugh]

Originally Posted by Davydd

Solar is an option. I've seen numerous different configuration as few are alike. However, I don't recall any ARV without solar. Solar to me basically cancels out your refrigerator use, parasitic, inverter, and other always on 12v stuff and then only in optimum conditions (sun, summer, orientation, high noon and no shade). Low angle winter short days I find it almost insignificant. Driving in the open the alternator is contributing way more and a day's use of electricity always tops off in less than an hour.

First, in theory if you have Autogen turned on your batteries should never run down to the preset cutoff of 20% ARV uses. On top of that I have my Autogen programmed to come on at 30% Still, I never invoked it because of battery depletion. I have by testing. There is a lot of safety factor built in. I'm not sure how Roadtrek does theirs. They say 10% and then Voltstart comes on. They don't say if Voltstart is programmable, is able to be turned off or what a procedure would be if the batteries depleted.

I did deliberately run my batteries down by turning off Autogen and turning on everything I could to deplete the battery. To get to that point I had to let it sit in my driveway for three days and then turn on everything so I could be there the moment it happened. It can be like watching paint dry. When it depleted 640ah it all shut down. To bring it back online you can either start your engine or plug into shore power. Then you have to manually hold down the top half of the battery disconnect toggle switch for approximately 6 minutes and that force charges the batteries and that is approximately 1% of charge or up to 21%. As you can imagine since you have to manually hold a toggle switch down it would take forever with solar. 6 minutes is agonizingly a long time. Silverleaf then comes back to life. After you recover you then just continue to charge be it by idling the engine, being plugged into shore power or driving. High idle via Autogen is going to run a programmed, in my case, 110 minutes, which means I would restore about a usable 400ah. Driving will top off the battery in under 3 hours. Plugged into shore power would take about 6 hours. I'm working with a usable 640ah of an 800ah battery. 160ah or 20% are in that unusable reserve.

Very good, I expected the process was as you described...

[avanti]

Originally Posted by Davydd

To bring it back online you can either start your engine or plug into shore power. Then you have to manually hold down the top half of the battery disconnect toggle switch for approximately 6 minutes and that force charges the batteries and that is approximately 1% of charge or up to 21%.

Just to beat this horse into an unrecognizable pile of meat:

It seems to me that the above "last gasp" procedure is EXACTLY analogous to the cold-weather recovery procedure that we have been advocating:
--It is not "a normal everyday need"
--It does not "affect everyday use"
--It "may never happen and I seriously doubt anyone of [us] has ever encountered a situation with [our] Bs where it could have happened had [we] known the parameters ahead of time."
--Anyone worrying about it might be accused of "Chicken Littleling".

And yet this is portrayed as an appropriate feature and the cold-weather equivalent is trivialized. What's the difference? Um, well... ARV implemented one but not the other.

[Davydd]

All ARV discussion is fair game here. I'm not against having a cold weather battery recovery feature. I just don't think I would ever encounter needing it and I live in the worst conditions of Minnesota and it is not catastrophic in any way. It can be a nuisance I agree but common sense and anticipation can prevent its need. I know my usage parameters and there are no what ifs that I can foresee. In that regard I am not compromising anything.

This was not something I thought about before buying. Most things about 12v, 120v and lithium ion batteries were a complete mystery to me. Charging freezing batteries was unknown to me at the time but not to ARV. But I am trying to find out things. I learned how to jury rig an oil heater on a creeper to restore the battery temperature through experimentation with a 15 amp circuit just about every home has. I was quite proud of my ingenuity. The oil heater and creeper were both things that had been unused and stored in my garage for years. I get my revenge on the other half that believes this packrat should get rid of things. Now you have my curiosity. Could I do the same with just a 1500w ceramic cube heater? I plan to take one to Tahquamenon Falls where there will be shore power under the theory you are using someone else's energy you paid for so why not use it. If it worked (but I am not going to bother to test) then I could be carrying everything I need but the shore power for that what if.

Why do I not worry about it? In a decade of Class B travel over 160,000 miles I don't think I ever encountered a situation where my batteries could go below freezing. So cold storage at home would be the only what if. Cold storage in my case negates all the benefits I have being plugged into shore power.

I don't doubt ARV could solve it easily if you asked. It would perhaps add some complexity especially in regard to the engine running idea. With the batteries disconnected the engine would be useless unless there was a dual heating system. The alternator connects directly to the battery bank. When the battery is disconnected the alternator does nothing. So there would have to be a separate dual system unless you eliminated what is used now and just relied on the engine. Also relying on the engine as a singular heating system would negate off grid capability the present system provides in my mind and would have to be highly complex to autostart and be a nuisance when needed for an ongoing operation in cold weather. Plus I doubt one would want autostart of an engine in cold storage.

120v heating pads instead of 12v and plugged into shore power would be the easiest solution assuming it would bypass the inverter like the other ARV 120v systems do plugged in when the battery is disconnected. I'll leave it to technical experts to decide if that would be worth doing or what other unintended consequences might ensue. One might obviously be how the Silverleaf monitors and controls it. The problem is right now the Silverleaf shuts off with the battery disconnect making an external solution more practical I think.

We are basically talking about a one time recovery event and not a continuing process as the present battery heating system does. Can you think of other solutions?

[Davydd]

Originally Posted by avanti

Just to beat this horse into an unrecognizable pile of meat:

It seems to me that the above "last gasp" procedure is EXACTLY analogous to the cold-weather recovery procedure that we have been advocating:
--It is not "a normal everyday need"
--It does not "affect everyday use"
--It "may never happen and I seriously doubt anyone of [us] has ever encountered a situation with [our] Bs where it could have happened had [we] known the parameters ahead of time."
--Anyone worrying about it might be accused of "Chicken Littleling".

And yet this is portrayed as an appropriate feature and the cold-weather equivalent is trivialized. What's the difference? Um, well... ARV implemented one but not the other.

OK expert, how would you do it? It is a relatively easy non complex recovery and restoration so I don't know what your problem is with it.