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Discussion Starter · #1 ·
... I'm hoping to get educated first. Thanks in advance!

My needs/wants: DC power for lighting (indoor and outdoor), refrigerator, maxxair, webasto heater, and charging ports. AC for appliances (induction burner, TV?) and other things that I haven't thought of yet.

Current situation: I already bought a 200Ahr LiFePO4 battery (SOK, $1100). I know it's likely overkill, but hopefully I'm future-proofing my electrical system. I'm trying to size my solar and inverter to the battery. Again, maybe a backwards way to do it, but this is where I'm at. The battery is sitting here on my desk, but I haven't bought any other components yet. Thinking I'll need: MPPT controller/B2B charger, inverter, cables, connectors, breakers, etc.

First question: I would like the option of running an induction cook top. I already have a cheap single-burner model that says it needs 1300W. So this means I need at least a 1500W inverter, right? And it means my battery needs to be able to spit out 1500W (or 125A)? The SOK battery specs say that it will do a max continuous discharge of 100A. Does this mean I would need TWO batteries if I wanted to run this burner? The induction burner was cheap and I'm not going to buy more battery capacity, but I'm using this question as a way to understand how to design these van electrical systems.

Next question: solar. I was planning for 400W of solar because it seemed like the right amount of power/money/roof space, but I didn't use any exact science for this. Again, I'd like to future-proof, so installing "too much" solar now is preferable to me than adding on later. Does this seem reasonable?

I'm spending hours reading posts and comment threads on this site, but if you think there's something I've missed please point me in the right direction.

Thanks!
 

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... I'm hoping to get educated first. Thanks in advance!

My needs/wants: DC power for lighting (indoor and outdoor), refrigerator, maxxair, webasto heater, and charging ports. AC for appliances (induction burner, TV?) and other things that I haven't thought of yet.

Current situation: I already bought a 200Ahr LiFePO4 battery (SOK, $1100). I know it's likely overkill, but hopefully I'm future-proofing my electrical system. I'm trying to size my solar and inverter to the battery. Again, maybe a backwards way to do it, but this is where I'm at. The battery is sitting here on my desk, but I haven't bought any other components yet. Thinking I'll need: MPPT controller/B2B charger, inverter, cables, connectors, breakers, etc.

First question: I would like the option of running an induction cook top. I already have a cheap single-burner model that says it needs 1300W. So this means I need at least a 1500W inverter, right? And it means my battery needs to be able to spit out 1500W (or 125A)? The SOK battery specs say that it will do a max continuous discharge of 100A. Does this mean I would need TWO batteries if I wanted to run this burner? The induction burner was cheap and I'm not going to buy more battery capacity, but I'm using this question as a way to understand how to design these van electrical systems.

Next question: solar. I was planning for 400W of solar because it seemed like the right amount of power/money/roof space, but I didn't use any exact science for this. Again, I'd like to future-proof, so installing "too much" solar now is preferable to me than adding on later. Does this seem reasonable?

I'm spending hours reading posts and comment threads on this site, but if you think there's something I've missed please point me in the right direction.

Thanks!

Usually what you want to do is design the loads to pull 1/2 of the max rating if possible, so:

(0.5) x (100 amp max rating ) = 50 amps (goal)

(50 amps) x (nominal 12 volts) ~ 600 watts

That is fairly conservative so you can go higher but be careful as you approach that max continuous amp rating.

You can test that induction stove at home and see how it does running at 600 - 800 watts. If it is enough heat then you can get away with it.

This is where sometimes it is better to purchase 2 or even 4 smaller amp-hr capacity batteries.

The reason is that sometimes 2 x 100 amp-hr batteries can (each) output as much current as that one.

Sometimes it makes sense to just use a camp stove that runs on a 1 lb bottle of propane.
 

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... I'm hoping to get educated first. Thanks in advance!



Next question: solar. I was planning for 400W of solar because it seemed like the right amount of power/money/roof space, but I didn't use any exact science for this. Again, I'd like to future-proof, so installing "too much" solar now is preferable to me than adding on later. Does this seem reasonable?



Next question: solar. I was planning for 400W of solar because it seemed like the right amount of power/money/roof space, but I didn't use any exact science for this. Again, I'd like to future-proof, so installing "too much" solar now is preferable to me than adding on later. Does this seem reasonable?



Thanks!
The battery pack charge rate max can be a factor in the charging decision, but in your case is not a big deal for solar.

My own preferred approach is to make sure to have sufficient solar to do most of the work, especially when it comes to keeping the refrigerator running.

It somewhat depends on if you live in an area that is routinely hazy / overcast vs a location that has laser like sunbeams such as Albuquerque.

For this area (San Jose, CA roughly) my testing indicates that locally it is better to use poly panels to better capture the sunlight especially over the winter vs mono.

In AZ / NM a mono type panel is better.

400 - 600 watts of panels in this area is about right for most vans powering a refrigerator and some other items. 300 watts is often short.

Again - in this area, 600 watts of panels would produce roughly:

(600 watts nameplate) x (50%) x (6 hrs / day) ~ 1.5 - 2 kW-hrs of power per day. A lot less during Jan / Feb and then again a lot less during August do to the annual fires.

Since you have a relatively small battery capacity, you should size your solar as large as feasible so that it can be easily recharged each day.

Personally I would skip battery to battery charging for now unless your loads change substantially or you live in a region with heavy overcast.
 

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@HarryN is right. The SOK 206Ah and 100Ah have the same 50/100A max charge/discharge rates. Two 100Ah (or two 206Ah) in parallel would have twice the max charge/discharge as one 206Ah. Our 2000W inverter has a max pull of 270A. We use a cheap induction hob rated at 1200W, but we almost never run it above 800W, except to boil water. Most of the time, it and our electric tea kettle pull about 80A DC each.
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
This is just a thought -- feel free to ignore it :)

You are ending up designing your whole electrical system around the induction cook top. Is this really worth it? You could go with a butane or propane cook top (as millions of RVs do) and not worry about sizing your whole system around the induction cook top.

The other 120Ac load you mention is the TV. There are lots of 12 volt TV's out there -- we use one, and its fine. It also movie disk player built in that we use quite a bit.

Gary
 

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Discussion Starter · #6 ·
Hi,
This is just a thought -- feel free to ignore it :)

You are ending up designing your whole electrical system around the induction cook top. Is this really worth it? You could go with a butane or propane cook top (as millions of RVs do) and not worry about sizing your whole system around the induction cook top.

The other 120Ac load you mention is the TV. There are lots of 12 volt TV's out there -- we use one, and its fine. It also movie disk player built in that we use quite a bit.

Gary
I'm actually designing it around the battery, and just trying to understand the limitations that its power output puts on me. Sure looks like I should have gotten two of the 100Ahr ones and paralleled them, but no going back now! I know there are plenty of options for cooking, but not burning gas inside appeals to me for many reasons.

Thanks for weighing in, you all. I may bump up my solar panel wattage after this input. This is getting me closer to a functional electrical plan, which I'll post as soon as I can. Thanks!
 

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I just realized that you are in SF.

I have helped with a few van projects there.
 

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If you stick with the one 206Ah SOK for now, you might think about designing space(s) for at least two batteries just in case you change your mind later. My electrical system has morphed over time as I experience and learn more. So far, I haven't painted myself into a corner I couldn't get out of.
 

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Discussion Starter · #10 ·
I just realized that you are in SF.

I have helped with a few van projects there.
Thank you! I'm moving at a snail's pace at the moment because I have two kids under 5, BUT hoping to gain some momentum this June and get the electrical installed. I'll reach out!
 

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Discussion Starter · #11 ·
If you stick with the one 206Ah SOK for now, you might think about designing space(s) for at least two batteries just in case you change your mind later. My electrical system has morphed over time as I experience and learn more. So far, I haven't painted myself into a corner I couldn't get out of.
Yeah, this is wise. I'm starting that layout process now, but have some tough space constraints trying to leave room for the kids to have a bed. My suggestion for putting them outside in a tent wasn't met well from my other half. I'll definitely leave room for a 2nd battery though. 😂
 

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Thank you! I'm moving at a snail's pace at the moment because I have two kids under 5, BUT hoping to gain some momentum this June and get the electrical installed. I'll reach out!

Once you have selected all of the parts it is too late for me to do anything useful for you. I mostly work on systems that I have a significant hand in the design / component selection.
 

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Yeah, this is wise. I'm starting that layout process now, but have some tough space constraints trying to leave room for the kids to have a bed. My suggestion for putting them outside in a tent wasn't met well from my other half. I'll definitely leave room for a 2nd battery though. 😂
Depending on where you travel, let your other half win this one.
 
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