Advancing Alvar - Page 17

gerrym51 · 10-02-2014, 08:56 PM

'Danger Will Robinson-danger'. i would have been shocked if you didn't go on.

markopolo · 10-02-2014, 09:39 PM

Just some general notes. (not necessarily related to your Advanced RV build) There seems to be a lot of DIY camper van builds in progress now and some people may just use the numbers you provided for your Advanced RV build for their DIY builds.

The first (previously mentioned) is to do with microwave ovens. They all have two wattages stamped on them or on a sticker. One is the cooking watts and the other is the power consumption watts. For anyone contemplating running a microwave oven off an inverter the power consumption watts is the number that matters. It is typically 50% more than the cooking watts. I have a 1,000 watt (cooking watts) microwave oven in my kitchen and the power consumption watts listed right on the sticker visible as you open the door is 1,500 watts. I have a 600 watt (cooking watts) microwave oven in my camper van and the power consumption watts listed on it is 900 watts. Also, if the microwave oven has a convection option then the power consumption watts in convection mode will be higher than the microwave cooking watts. I just checked one 1,000 watt cooking power Dometic Convection / Microwave oven listed at Camping World. Microwave power consumption was listed at 1,450 watts, convection mode was also listed at 1,450 watts.

The 1,450 watts listed probably allow the appliance to have a 15 amp 120v plug. (15a x 12v = 1800w x 80% = 1440 watts). The Apollo half-time microwave convection oven in the Trail-Lite RV I owned had a 20a 120v plug. (needed a 20a wall outlet to plug into)

The other note is about inverter efficiency ratings. There would be an approximate 10% "penalty" on the amp draw if the inverter is rated 90% efficient in converting 12v DC to 120v AC. Because of that and also some losses do to wiring etc. you'll often see (or used to see) the calculation for estimating the amp hours used when running a 120v item off an inverter expressed as watts divided by 10 (not 12). So a 90w 120v LED TV might actually draw around 9ah for example.

Example: someone hoping to use a 1000w (cooking watts) microwave oven through an inverter might do the calculation as 1000w/12v=83a when it really would be closer to 1500w/10=150a ..................... big difference between 83a and 150a!

I can't wait for you to actually get Alvar on the road and report back on how it all works.

booster · 10-02-2014, 10:25 PM

We have a Samlex 1500 watt inverter, and Samlex has a chart to calculate how big an inverter you need to run various things. IIRC, the microwaves are the only things that didn't use the power consumption number, instead using the cooking power, which was then multiplied by 2. Other items had much higher multipliers, especially those with compressors like AC or frigs. It also makes a difference if the inverter is pure sign wave or not for some loads, and microwaves are said to not like the modified sign wave inverters. How many amps our 700 watt microwave pulls is very voltage influenced. If it is on low batteries and pulling down the voltage to the low 11's, it can pull 120 amps. If the batteries are full and we have the engine running, it will hold 13 volts and pull about 105 amps or less.

markopolo · 10-02-2014, 10:49 PM

I've seen 90 amp DC draw with my 600 watt microwave oven. That's in line with what you've seen; 120 amps with 750 watt microwave oven.
Do you know the power consumption watts on the microwave oven in your RT?

Davydd · 10-02-2014, 11:39 PM

As you can see, the microwave is a minor part of our use and is listed in our optional voluntary use. Maybe my wife will heat a cup of water for a minute to make her nightly tea. The worst case scenario is if I decide to start having nightly popcorn at 3 minutes. Also, I imagine if we bake in the convection oven part we would probably only do so on days we are plugged into shore power. We will still have plenty of those days since most state parks we like have it.

The inverter is a pure sine wave 2800 watt Outback, at least I thought. It is a monstrous looking thing in my mind as it is bigger than a typical battery. Advanced RV gave me a sheet saying maximum wattage of the inverter to be 3,450. I'm not sure what that means or if they have changed it, or if the 2800 is a generic number, or maybe the 2800 number is the realistic efficiency number. I guess it is something to look in to, but then again, it isn't going to change. I'm sure I will learn real fast how much I can run simultaneously just as I have with our converter system Bs when plugged in.

You guys know my incessant dissing of air conditioning. I hate it. BTW, we got through this past summer in Minnesota without once using a portable air conditioner I bought for our home last summer after 30 years without at my wife's insistence.

The second alternator on Advanced RV is charging at a rate of 300 ah. They've done some stuff to ensure that including keeping it from getting too hot and losing efficiency. If it truly performs that well I could replenish as I mentioned the battery bank driving 100 miles. We probably would typically drive more than that in any driving day.

I learned one other interesting thing. If storing your RV for any length of time and plugged into shore power, the system will trickle charge the chassis battery. I don't have any details how that happens. My last two Bs never did that.

As I mentioned, I am starting to think Solar, after Booster's reports, is mostly frosting. It might not factor in much at all especially camping in wooded areas. Maybe it will be great at Quartzite, Arizona in the desert.

I think the second alternator will work fine to the point I even doubt I'll use that high idle autogen option much if at all. The 600 ah lithium battery pack is equivalent to putting in NINE 12V lead-acid batteries and I already could dry camp 5 straight days on two. My gut says I have over estimated.

avanti · 10-03-2014, 12:04 AM

The only reason that solar is NOT frosting for most people is that it will keep your batteries topped off and healthy during storage. Of course, this is only relevant if (a) you park outside and (b) you do not leave the rig plugged in. But, having lived without solar for many years and now having it, I will report that it is really nice to not have to worry about plugging and unplugging before and after each trip.

Davydd · 10-03-2014, 12:26 AM

That would be nice. Have you ever encountered a cord incased in ice?

I have a level spot side spot and a 30 amp service at my house so have always left my Bs plugged in. With my first B I learned about intelligent charging.

It is heavily wooded too but the sun would shine on it a couple hours. I'd probably have to trim back a few trees to ensure that but wouldn't want to with the Maples. With my investment I am going to have to either build a new garage for it or find a rental garage I think. I have tired of clearing snow off and keeping snow clear around it. This coming winter won't be a problem. We will probably pick it up and head straight for Arizona after a short stop at home to load it up.

markopolo · 10-03-2014, 12:37 AM

I'm guessing a single stage charger in your first B Davydd

This is where it gets interesting with lithium batteries in RV's - do you keep them topped up or store them at 80%? Does Advanced RV have any data on that? Does anyone have any links to share on what state-of-charge to store lithium batteries at for optimal longevity?
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Just a note on Inverter efficiency ratings:

The efficiency rating is the maximum percentage of power drawn from the 12v battery that can be converted to 120v AC due to the design of the inverter. The output rating of the inverter is a different measurement.

Some Outback inverters have an efficiency rating of 90%
http://www.outbackpower.com/outback-pro ... ory_id=446

You'd think 10 amps at 12 volt would be to 1 amp at 120 volts through an inverter but it does not work out like that. It would be more like .9 amps available at 120v because the inverter is only 90% efficient. It actually could be much worse with small loads. Here are some test results that really demonstrate the inverter loss with a very small load: http://www.classbforum.com/phpBB2/vi...9&t=1038#p3758 My fully charged but idle laptop used 26.4 watts when plugged into a wall outlet and used 37.2 watts when plugged into the inverter!

And a note on inverter output ratings:

Most inverters will have multiple output ratings. The main one is the continuous output rating; 2800 watts in the VFX2812M linked above. That particular model also has a surge overload rating of 4800 watts, a 5 second rating of 4000 watts, a 30 minute rating of 3200 watts. I just picked that model as an example.

booster · 10-03-2014, 01:45 AM

I misspoke about our microwave above. It is 700 watts, not 750, cooking power.

Marko, the manual shows it at 1000 watts input.

Davydd · 10-03-2014, 03:11 AM

Interesting information Marko. I obviously have a lot to learn. I still feel a bit confident I will have more than I need if not agonizing over an air conditioning factor it seems a lot of people do. I went into this thinking 400 ah of lithium batteries would do it and it probably would. I built supposition scenarios for 600 ah that I seriously doubt I will ever reach. I couldn't think of any way I could use 800 ah unless I became a bread baker or something.

I'll still periodically seek out campgrounds with dump stations and water fills which means I will also be getting my share of electrical sites. With 40 gallons fresh, 26 gallons grey and 18 gallons black I suspect I could stretch my average every 4-5 days out to a week.

markopolo · 10-03-2014, 05:09 AM

I think you'll have plenty of power also. I wish you had the RV already and were out testing it!

Arlo · 10-03-2014, 04:23 PM

Forgive me, Davydd, if I have missed this in past posts, but will Alvar have a pressure tank on the water pump to keep it from cycling as frequently? We seem to share a distaste for generator and A/C noise, and I'm starting to get an attitude about water-pump noise too. It's especially jarring after a wee-hours toilet flush!

Davydd · 10-03-2014, 04:57 PM

Arlo,

I won't know until I get and use the RV. I understand what you mean. What I do know is ARV is using the Shurflo Revolution water pump which is an upgrade to all the Shurflo water pumps I have seen in most Class Bs including my two (P-W and GWVan). Is it an improvement in regard to the jarring juddering concern? It is bigger and more powerful and Shurflo describes it as "super quiet." I don't know if there is much choice in water pumps in the RV market. I don't recall ever seeing anything but the Shurflo brand.

Davydd · 10-03-2014, 05:00 PM

Quote:

Originally Posted by markopolo

I think you'll have plenty of power also. I wish you had the RV already and were out testing it!

The wait is agonizing. We shut down our fall touring and missed a BEE Social just so we can keep our Great West Van ready to sell.

Davydd · 10-03-2014, 05:25 PM

Here is Advanced RV's take on what they are doing...

Go Farther Off the Grid:Advanced RV Redesigns their Battery System

gerrym51 · 10-03-2014, 05:31 PM

Quote:

Originally Posted by Davydd

Here is Advanced RV's take on what they are doing...

Go Farther Off the Grid:Advanced RV Redesigns their Battery System

Daydd- i read the article-does this mean if below 32 degrees there is no way to charge these litium batteries? that's how i interpret it -but i could be misunderstanding!

Davydd · 10-03-2014, 05:54 PM

Gerry,

You can use lithium-ion batteries in below freezing weather if there is charge available of course. You cannot bulk charge the batteries below freezing weather but you can float charge. ARV has developed a heated battery box that is under the van and is heated to keep it above freezing when necessary. The SilverLeaf system controls all the activity. My concern was winter storage in Minnesota plugged into an electrical outlet. The batteries would be fully charged so float charging would only be going on but the shore power would also heat the battery box if necessary. In our travels we have often gone down to overnight camping temperatures around 18-20F but I don't recall any day that had not gone above freezing. Those were Rocky Mountain type conditions. I hope to not have to camp anywhere colder but we have traveled over the winter in our Bs without camping. We can easily get through a night with no need for charging.

BTW, that's MIke Neundorfer, Frank Kolasinski, me and my wife Nancy in that photo. If you want to know more about what they are doing, in the email I got this morning they also referenced Technomadia. Read what they are doing with lithium-ion batteries and you'll know more.

avanti · 10-04-2014, 12:01 AM

Quote:

Originally Posted by Arlo

will Alvar have a pressure tank on the water pump to keep it from cycling as frequently? We seem to share a distaste for generator and A/C noise, and I'm starting to get an attitude about water-pump noise too. It's especially jarring after a wee-hours toilet flush!

IMO, having a pressure accumulator is a complete no-brainer. The Shurflow unit like this

costs like $35 and is trivially easy to install (even as a retrofit).

I specified one in our new built-to-order GWV Legend (which, as far as I know, has the standard Shurflo pump). The difference from our previous Airstream Interestate is night and day. I won't say the pump is silent, but it is pretty close. It is barely noticeable when it runs. I can't swear that the accumulator is responsible for 100% of the improvement, but it is the only meaningful difference that I am aware of.

Everyone should have one of these.

Caped Crusader · 10-04-2014, 01:10 AM

With an On Demand pump from Flo-Jet, or Surflo you shouldn't get any hammering, at least I don't.
I replaced my water pump in 2003 with a Flojet, and I'm sure tech has improved since then.
I can barely hear mine when it runs. I never saw a need for an accumulator.

avanti · 10-04-2014, 01:58 AM

Quote:

Originally Posted by Caped Crusader

With an On Demand pump from Flo-Jet, or Surflo you shouldn't get any hammering, at least I don't.
I replaced my water pump in 2003 with a Flojet, and I'm sure tech has improved since then.
I can barely hear mine when it runs. I never saw a need for an accumulator.

Well, I dunno, but our 2005 Airstream Interstate was so loud that it was embarrassing in the campgrounds. Not sure what the difference is. Maybe the tech has gotten WORSE since 2003. It happens.

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