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Discussion Starter #1 (Edited)
I am ordering a Ford Transit High Roof and will be doing a custom conversion. Here are what I evaluate to be my electrical needs. This is the extreme high end of what I estimate my usage to be! For instance, this is running my Webasto heater full blast for 24/7. I plan on insulating very well but I also plan on boondocking in the middle of the mountains during the winter! Even so, it is my understanding that the Webasto won't need to run 24/7. I am getting the 230A alternator and the dual 70A batteries, but needless to say I am going to need more. Is this realistic, or is it likely I am over-estimating with these numbers?

Appliance------------DC Amps--Hours----Amp Hours
Webasto Air Top-----2.45--------24-------58.8
Stereo----------------0.8---------4---------3.2
water pump----------4.5---------0.15-----0.675
fridge-----------------6-----------8---------48
induction cooktop----150--------0.6-------90
microwave-----------50---------0.068----3.4
laptop-----------------5.6--------4---------22.4
cellphone-------------1.2---------2---------2.4
Led lighting-----------2-----------3--------6
maxxair fan-----------2.3--------4--------9.2


TOTAL AMP HOURS: 244.075

What might you suggest for a house battery or solar panel solution? So far, I think I want to connect the house battery to the alternator with a battery isolator/automatic charge relay. Assuming my numbers are realistic, I will need about 490 amp hours of battery. That sounds like a lot! Maybe I should forget the induction cooktop?
 

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Discussion Starter #3
Um... going to compute anything into wattage needs too?
Not sure how important that is for my planning. I realize that system wattage determines how many things I can run at once, but I don't see me needing to do many of these things at the same time.
 

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I run a full river 12D batter that's 260ah. Two of those together would be 520ah which would be a lot of energy and probably enough to run what you list. I think you are high on the heater usage. If you insulate I can't imagine it would run 24/7. I don't have the webasto so I can't speak from experience. It just seems like a high usage to me.

The other question is charging it. I have one 315 watt panel up top charging my battery and it handles it quite nicely. No problem getting back to 100% charge daily. With heavy electrical usage the question becomes how much solar panel to get 520 ah batteries up to 100%. Will you even use solar. Will you use the vehicle to charge it up? Or a combination of both.

I'll be using propane to cook. I know the induction cook tops work great for some. And I would be very keen to use it. It just seems like the energy used is too much for my simple set up. I have propane heat so propane for cooking was easy for me.
 

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Hi there. Interesting you are looking at all electric, which is what I am doing, including the induction cook top.

Your calculation is pretty reasonable, and as you stated on the high side which is good engineering. Using the 50% battery discharge rule 500Ah sounds OK. I am planning at least three times that, but I am also looking at running AC and all electric heat off it.

One thing you didn't calculate in is the parasitic loss of an inverter. They get hot, those are amps too.

As for wattage, that's easy: 244A x 12V = 2900W.......... Ten hours of maximum solar charging and you need a 300W "array".

And that would work. In the desert. In July. My rule of thumb is 50%...... For winter, and clouds and dirt and whatever else degrades the output of a panel...... so 600W.

In my experience there are two periods of the day where usage is high. Breakfast with it's coffee maker, omelet, hot water etc etc, and dinner with cooking and dishes and human washing.

One way to knock the requirements way down is to introduce limited fossil fuel during these hours. And no, I don't want to add propane to the equation either.

I plan on running a Honda 2000eu for those few hours. I want to tap into the secondary fuel pickup so I don't have to carry fuel, and run it during kitchen hours. This will take a huge load off the system, as it will even be charging. For you 150 or so watts of solar would easily fill up the rest of the requirement.
 

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Microwave power is too low. My 600 watt microwave pulls 83 amps (as measured). 600 watts is output power not input power requirement. Also, I doubt you will be using it for only 4 minutes per day. Induction cooktop is certainly driving your requirements. Not sure of another solution if you want to avoid propane.
 

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We went with propane for cooking, (along with hot water and house heating). Mainly because of the huge hit an induction cooktop takes to electrical storage. Otherwise, I'd guess your usage is about right, outside of running heat 24hr/day. Looks to be similar to our loads.

That said, we have 2 4D size AGMs (about 400AH) and 560W solar. So far, we can keep up with our electrical needs...even here in the Pacific Northwet. (Full disclosure: Annie is still under construction, with only shakedown trips to date.) I doubt we could keep up if we ran the induction cooktop. We don't plan on needing the (dual) car batteries for house use, but have the two systems tied together with an ACR. Mainly used to top off the car with a good solar or shore powered profile.
 

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Do not see inverter on the list. For AC items the efficiency of the inverter is somewhere around 90%. The inverter if left on all the time uses power. If I leave my 1000 watt inverter on overnight without any loads it will use about 6% of my 255 amp-hr battery capacity. I only turn it on when I need 120 volt power.

My "600" watt microwave draws 950 watts.

My 85 liter refrigerator uses 40 watts and runs about 25% of the time.

You will haul around a lot of weight in batteries due to the induction cooktop. Cooking with 1# propane bottles works. Propane stove is portable so can be used outside.

Computer and laptop could be charged from a vehicle powered inverter some of the time.

Doubt that the LED lighting would require that much electrical. Many conversions have excessive lighting and are wired to turn all on at once. I had too many lights in the sold Sprinter so have less in Transit. Each light has individual on/off switch where I would be standing when I need the light. Never more than two on at the same time.

I seldom power the Maxxair fan. Open it and the 4" square floor inlet hole to get natural air flow without powering the fan.

You have not stated what climate conditions you expect to be in. Makes a difference.

With my electrical usage in a mild climate my single 300 watt solar panel normally supplies all the power required. As a backup in case of bad weather I can charge from a vehicle powered inverter.
 

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I am ordering a Ford Transit High Roof and will be doing a custom conversion. Here are what I evaluate to be my electrical needs. This is the extreme high end of what I estimate my usage to be! For instance, this is running my Webasto heater full blast for 24/7. I plan on insulating very well but I also plan on boondocking in the middle of the mountains during the winter! Even so, it is my understanding that the Webasto won't need to run 24/7. I am getting the 230A alternator and the dual 70A batteries, but needless to say I am going to need more. Is this realistic, or is it likely I am over-estimating with these numbers?

Appliance------------DC Amps--Hours----Amp Hours
Webasto Air Top-----2.45--------24-------58.8
Stereo----------------0.8---------4---------3.2
water pump----------4.5---------0.15-----0.675
fridge-----------------6-----------8---------48
induction cooktop----150--------0.6-------90
microwave-----------50---------0.068----3.4
laptop-----------------5.6--------4---------22.4
cellphone-------------1.2---------2---------2.4
Led lighting-----------2-----------3--------6
maxxair fan-----------2.3--------4--------9.2


TOTAL AMP HOURS: 244.075

What might you suggest for a house battery or solar panel solution? So far, I think I want to connect the house battery to the alternator with a battery isolator/automatic charge relay. Assuming my numbers are realistic, I will need about 490 amp hours of battery. That sounds like a lot! Maybe I should forget the induction cooktop?
Hi,
Just looking at your table...

As you say, the furnace looks kind of heavy unless you camp in extreme cold weather. Our van is well insulated with an 8000 BTU/hr output furnace. At 22F outside, it runs about half the time.

The fridge seems about right to me -- our measured fridge energy consumption was 42 amp-hrs on an 80F day: http://www.buildagreenrv.com/design-and-build-information-for-camper-vans/installing-galley/measuring-refrigerator-electricity-use/

Don't have any experience with induction cooktop, but seems like its your dominant load. Wondering if its worth it? We use a gas cooktop that is permanently mounted to the counter, but if I had it to do over, I'd probably go to a butane canister powered cooktop that can be used inside or outside -- lots of people really like being able to cook outside.

Given that this is probably pretty much a maximum use scenario, I would size the battery pack for 80% depth of discharge for this kind of day. This will very likely mean that you will be less than 50% depth of discharge on a more typical day. Even if you hit 80% discharge fairly often, batteries have good life for RV service at 80 % DOD -- for example Trojan says 750 cylcle at 80% DOD on their FLA gold cart batteries: http://www.buildagreenrv.com/design-and-build-information-for-camper-vans/install-electrical/picking-and-sizing-house-batteries/ For typical RV use, that's quite a few years.

That would give you 244/0.8 = 305 amp-hrs for the battery pack capacity.
This would be for one day -- if you want to be able to do multiple days without running the engine or having some good solar charging (which is challenging in the winter), then it goes up accordingly and gets out of hand pretty fast. Seems like best solution for multi day use is to cut back on energy use and get the most efficient appliances possible?

We recently added a battery monitor to our system, and on the last trip I recorded State of Charge and amp-hrs used each morning. I was surprised how little we used even with the cold weather camping: http://www.buildagreenrv.com/trip-reports-experiences-and-lessons/banff-trip/
Our usage average only about 40 amp-hrs overnight which left us above 80% SOC each morning. This was in 20F weather with a lot of furnace use. Our loads are not a lot different from yours except for the induction cooktop. But, we were driving each day, so no use during daytime hours and each evening started with a fully charged battery.

Gary
 

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Discussion Starter #10
Humm, maybe on the road I will use a microwave more, but right now, I use it about 2 minutes in the morning and maybe 3 days a week I will warm up soup at about 5 min at %50 power.

Climate wise, I would like to be ready for EVERYTHING! Not only do I live in CO, where it tends to very quite a bit, I plan on being able to travel just about everywhere save Antarctica.

Thank you all for the replies so far, they are very helpful for consideration!
 

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... I was surprised how little we used even with the cold weather camping: http://www.buildagreenrv.com/trip-reports-experiences-and-lessons/banff-trip/ ...
That's a great report. And I'm glad to see you had a nice trip.

Regarding your comment about keeping a water system warm, I did install my water system in the same cabinet as my Espar heater for that reason. I haven't tried it out yet so I can't say if a very low Espar temperature setting will keep it all from freezing. By next winter I should know.

Thanks for the inspiration.
 

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... I will need about 490 amp hours of battery. That sounds like a lot! Maybe I should forget the induction cooktop?
If you're going to set things up for a microwave, bringing a portable induction cooktop costs nothing extra. And sure, bring some sort of fuel burning stove too. Then you'll have lots of choices.
 

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If you're going to set things up for a microwave, bringing a portable induction cooktop costs nothing extra. And sure, bring some sort of fuel burning stove too. Then you'll have lots of choices.
You can run a "600" watt microwave on a 1000 watt inverter. Most (all?) induction burners require a larger inverter. People usually select a 2000 watt inverter when they have an induction burner. Also suspect burner will require a larger battery bank.
 

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You can run a "600" watt microwave on a 1000 watt inverter. Most (all?) induction burners require a larger inverter. People usually select a 2000 watt inverter when they have an induction burner. Also suspect burner will require a larger battery bank.
True. I was assuming a setup on the larger side of things.
 
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