Dodge Caravan mini RV conversion

[DakotahJennings]

Hey there folks!

Being a new member, I'll state the usual. I hope this is the right place for this, if not, I apologize.

Here is a project that I have in mind, and I was hoping I could get some input, as I am less than novice when it comes to solar. My knowledge consists of a couple days studies on youtube and google so bare with me.

I've got a 1998 dodge caravan that I gut out and set up for "living on the road". Its got my military cot, ruber maid dresser and a few nick nacks. Not much for space, but I'm not to picky since its comfortable and I have a 10x10 tipi tent. But I want to take it a step farther.

I'd like to set up a solar system on the van so that I can power a small 19'' LED/LCD TV, maybe a small osculating fan, and my laptop for 4-6 hours a day.

I read somewhere that an LED TV requires 200 watts to operate. With what little knowledge I do have, my assumption is that the more you have plugged in, the more you'll need. So for example, a laptop + 19'' LED TV would require around 300 watts of power?

So I guess I'll link the items I'm looking at purchasing and hope that I'm at least on the right track. If I'm wrong, I'll gladly take any correction needed.

First off, the solar setup I'm looking at is a 100W Monocrystalline solar pannel starter kit off amazon that can be found HERE. The guys on amazon said it would be "more than enough" for what I wanted to do.

Next I have my inverter. After seeing how expensive they could be, I jumped on THIS 1200 watt inverter for $75.

And lastly x2 12v golf kart deep cycle batteries for just under $100.

From my understanding, between the starter kits controller, the inverter and the batteries, this should be all that is needed to set up my van to be solar efficient in running my laptop/TV/fan for a few hours each day. (Don't worry, I didn't forget the battery cables to connect both 12v batteries together for the power bank.

Ultimately. What i would like to do is build a box to make my "power bank" holding the batteries, the controller, and the inverter. Set up the solar panel on the roof of my van, and make my vans battery the primary battery and hook everything up to the alternator for a dual charge setup so to benefit from the power generated via driving as well as the panel on top. I'm unsure if this is a conflict of interest, but I'm hoping everyone will understand my lack of knowledge and respond in a kind manner.

I just don't want to ruin a $400 setup because I didn't ask for help when I should have. So I've come here to bring my idea to the table and seek out any guidance and information that might be available.

I appreciate your time =)

Sincerely,
DJ

[Sunking]

I'd like to set up a solar system on the van so that I can power a small 19'' LED/LCD TV, maybe a small osculating fan, and my laptop for 4-6 hours a day.

I read somewhere that an LED TV requires 200 watts to operate.

Well do not go back to where you read that as it is far from reality. A 19 inch LEd TV depending on manufacture and brand consumes 20 to 30 watts at most. Get a good unit made to operate on 12 volt DC and just under 20 watts. 200 watts my arse.

Now for the good news. You have no use for solar, so need to go to all that expense. All you need is a pair of 6 volt golf cart batteries and a Electronic Battery Isolator and let your van alternator do all the charging. Your vehicle alternator will generate more power in 30 minutes than a 100 watt solar panel can do in a week. A good Isolator will cost you less than $100. Some of the best are made by ASE a Cooper Industry company and Model 702 sounds like your ticket and will run you around $28 to $35. Lot less expensive and will work a heck of a lot better than solar even when the sun goes down.

[DakotahJennings]

Well do not go back to where you read that as it is far from reality. A 19 inch LEd TV depending on manufacture and brand consumes 20 to 30 watts at most. Get a good unit made to operate on 12 volt DC and just under 20 watts. 200 watts my arse.

Now for the good news. You have no use for solar, so need to go to all that expense. All you need is a pair of 6 volt golf cart batteries and a Electronic Battery Isolator and let your van alternator do all the charging. Your vehicle alternator will generate more power in 30 minutes than a 100 watt solar panel can do in a week. A good Isolator will cost you less than $100. Some of the best are made by ASE a Cooper Industry company and Model 702 sounds like your ticket and will run you around $28 to $35. Lot less expensive and will work a heck of a lot better than solar even when the sun goes down.

I had been lead to believe an LED TV required 200W by some solar energy chart that was provided on one of the inverter pages on amazon. I didn't quite understand it, so it was mostly assumtion lol. But you bring good news!!!
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Now. My only concern about the system you've suggested (which blew my mind lol), is whether or not I'll have to leave my van running in order to use the TV/Laptop for a couple hours. With the price of fuel being so high, I want to conserve as much as possible. So I'm just wondering how long the batteries will allow me to use the TV/Laptop/fan before requiring a short drive to recharge.

Lastly, I'm going to have to do some homework on the Battery Isolator. I'm unsure of what it is as this is the first time I've ever heard of it but I can't thank you enough for your advice! $100 sure beats $400!!!

[Sunking]

I had been lead to believe an LED TV required 200W by some solar energy chart that was provided on one of the inverter pages on amazon. I didn't quite understand it, so it was mostly assumtion lol.

Well forget that website and the chart. No where near real numbers. More fantasy than fact.

Now. My only concern about the system you've suggested (which blew my mind lol), is whether or not I'll have to leave my van running in order to use the TV/Laptop for a couple hours. With the price of fuel being so high, I want to conserve as much as possible. So I'm just wondering how long the batteries will allow me to use the TV/Laptop/fan before requiring a short drive to recharge.

OK first you need to get your head wrapped around a few electrical principles to help you understand what you need and want. For now let's just concentrate on Power & Energy as they have two different meanings and related.

Power in the electrical world is called WATTS. Watts is just a measurement unit of electric power and is the Product of Volts x Amps = Watts at any given moment in time. For example a 60 watt light bulb. Think of it a a fuel or water flow of gallons per minute.

Energy in the electric world is Watt Hours = Watts x Hours or the the amount of heat energy consumed over a period of time. Going back to the 60 watt light bulb example if you turn the light on for 5 hours then you use 60 watts x 5 hours = 300 watt hours. If you were to use a 100 watt light bulb and used 300 watt hours would take only 3 hours, or a 300 watt 1 hour. So you need to understand the difference and relationship to each other before moving forward.

OK let;s say your LED TV uses 20 watts, Laptop 30 watts, and fan uses 40 watts and you want to run each say 4 hours each day. You need to determine the total watt hours use din a day. So

TV = 20 watts x 4 hours = 80 wh
Lap Top = 30 watts x 4 hours = 120 wh
Fan = 40 watts x 4 hours = 160 wh
Total = 80 + 120 + 160 = 360 watt hours in a day.

OK solar battery systems are very inefficient and depends on if you use a PWM or MPPT charge controllers. At best a PWM system is 50% efficient overall, and MPPT around 66 to 70% efficient. That means a solar panel would need to generate a minimum of 720 wh for a PWM system, and about 515 watt hours for a MPPT system.

OK so how many watt sin a solar panel does it take to do that. Well there are a lot of factors mainly depending on location, time of year, and panel tilt angle and orientation looking solar south. Well in a car or van you cannot tilt a panel or orient it to the south because it lays flat on the roof. That greatly effects you daily SUN HOURS. Oops there is a useful word hours. For example if you are say Kansas in July with a panel tilted at longitude +15 degrees you would have about 5.5 Sun Hours assuming you have clear view of the horizon south, east and west in the broiling hot sun all day from dusk to dawn. In a car with 0 degree tilt sitting in the broiling sun all you get is roughly 3 Sun Hours. So how big of a panel does it take to generate say 720 watt hours? Watts = Watt Hours / Hours so 720 wh / 3 Sun Hours = 240 watts. If you were to use a MPPT controller things improve a bit 515 wh / 3 h = 171 wats so you could use a 180 watt panel. In both examples each system generates the same 15 amps of charge current.

Moving on to battery. With lead acid batteries we normally like to have a 5 day reserve capacity. This does two things for us. 1. CYA for cloudy days when you do not have any charge current. In reality only gives you 2.5 days of useful reserve because you never want to discharge more than 50% of the battery capacity. 2. It extends battery life to maximum. As stated you never want to discharge more than 50%. If you only discharge 20% each day you can get up to 5 years of life out of a good quality battery. Discharge to 50% everyday and now looking at 2 to 3 years. Discharge 80% or more each day and now looking at 1 year at best. So how do you determine battery capacity. Well ideally you want 5 day reserve. So if you use say 360 wh per day you want 5 x 360 wh = 1800 wh. Bu twait batteries are not rated in Watt Hours. They are rated in Voltage and Amp Hours. What do you do. Well Watt Hours = Volts x Amp Hours. So to find the battery Amp Hour capacity all you need to know is the battery voltage and watt hours required. Amp Hours = Watt Hours / Battery Voltage = 1800 Watt Hours / 12 volts = 150 Amp Hours @ 12 volts.

OK lets forget solar and think vehicle alternator. Alternators are rated in Amps. I do not know how many amps your alternator produces but I can safely say at least 70 amps of charge current and likely more. You have to find that for yourself because I am not going to do your work. So if you use say that 360 watt hours each day, and we know the battery voltage is 12 volts then we know you would use 360 watt hours in a day / 12 volts is 30 Amp Hours. Taking into consideration battery charge efficiency of 85% your vehicle alternator wound take 30 Amp Hours / .85 / 70 amps = .5 hours or 30 minutes to recharge. Keep in mind you can go 2.5 days between charges if you have a 150 ah battery. If you went 2.5 days would require you to idle or drive roughly 90 minutes every 3 days.

Now do some rework. You want two 6 volt golf cart batteries. Golf cart batteries are rated around 200 to 240 Amp Hours. So that is a capacity of 12 volts x 200 amp hours = 2400 and 2880 watt hours respectively. If you use 360 watt hours per day you can go about 4 days to reach 50% discharge before having to idle or drive 2 hours to recharge.

So mow you have an idea of what it will take. Do you have the funds and room on your van to hold a 200 watt panel, and 15 amp MPPT controller. Just the panel and controller will cost you north of $400, plus another $250 for batteries. I seriously doubt you have room to mount two hundred watt of solar panel and would look pretty silly making you target for theft. You gotta decide. One other option I did not mention is a hybrid system where you use a small say 50 watt panel and a Battery Isolator. Panel would only supplement the alternator cutting fuel cost.

Lastly, I'm going to have to do some homework on the Battery Isolator. I'm unsure of what it is as this is the first time I've ever heard of it but I can't thank you enough for your advice! $100 sure beats $400!!!

Nothing magical. It is a device that isolates your starting battery from the house batteries when discharging. So when you are parked without the engine running and watching TV the power comes from the house batteries only and will not run down the vehicle starting battery. When the engine is running will charge both vehicle starting and house batteries. The Electronic types allow you to select the correct voltage for the house batteries as the vehicle battery runs at a slightly higher voltage. A 70 amp unit runs about $35. You size then according to your vehicle alternator.

[DakotahJennings]

Well forget that website and the chart. No where near real numbers. More fantasy than fact.



OK first you need to get your head wrapped around a few electrical principles to help you understand what you need and want. For now let's just concentrate on Power & Energy as they have two different meanings and related.

Power in the electrical world is called WATTS. Watts is just a measurement unit of electric power and is the Product of Volts x Amps = Watts at any given moment in time. For example a 60 watt light bulb. Think of it a a fuel or water flow of gallons per minute.

Energy in the electric world is Watt Hours = Watts x Hours or the the amount of heat energy consumed over a period of time. Going back to the 60 watt light bulb example if you turn the light on for 5 hours then you use 60 watts x 5 hours = 300 watt hours. If you were to use a 100 watt light bulb and used 300 watt hours would take only 3 hours, or a 300 watt 1 hour. So you need to understand the difference and relationship to each other before moving forward.

OK let;s say your LED TV uses 20 watts, Laptop 30 watts, and fan uses 40 watts and you want to run each say 4 hours each day. You need to determine the total watt hours use din a day. So

TV = 20 watts x 4 hours = 80 wh
Lap Top = 30 watts x 4 hours = 120 wh
Fan = 40 watts x 4 hours = 160 wh
Total = 80 + 120 + 160 = 360 watt hours in a day.

OK solar battery systems are very inefficient and depends on if you use a PWM or MPPT charge controllers. At best a PWM system is 50% efficient overall, and MPPT around 66 to 70% efficient. That means a solar panel would need to generate a minimum of 720 wh for a PWM system, and about 515 watt hours for a MPPT system.

OK so how many watt sin a solar panel does it take to do that. Well there are a lot of factors mainly depending on location, time of year, and panel tilt angle and orientation looking solar south. Well in a car or van you cannot tilt a panel or orient it to the south because it lays flat on the roof. That greatly effects you daily SUN HOURS. Oops there is a useful word hours. For example if you are say Kansas in July with a panel tilted at longitude +15 degrees you would have about 5.5 Sun Hours assuming you have clear view of the horizon south, east and west in the broiling hot sun all day from dusk to dawn. In a car with 0 degree tilt sitting in the broiling sun all you get is roughly 3 Sun Hours. So how big of a panel does it take to generate say 720 watt hours? Watts = Watt Hours / Hours so 720 wh / 3 Sun Hours = 240 watts. If you were to use a MPPT controller things improve a bit 515 wh / 3 h = 171 wats so you could use a 180 watt panel. In both examples each system generates the same 15 amps of charge current.

Moving on to battery. With lead acid batteries we normally like to have a 5 day reserve capacity. This does two things for us. 1. CYA for cloudy days when you do not have any charge current. In reality only gives you 2.5 days of useful reserve because you never want to discharge more than 50% of the battery capacity. 2. It extends battery life to maximum. As stated you never want to discharge more than 50%. If you only discharge 20% each day you can get up to 5 years of life out of a good quality battery. Discharge to 50% everyday and now looking at 2 to 3 years. Discharge 80% or more each day and now looking at 1 year at best. So how do you determine battery capacity. Well ideally you want 5 day reserve. So if you use say 360 wh per day you want 5 x 360 wh = 1800 wh. Bu twait batteries are not rated in Watt Hours. They are rated in Voltage and Amp Hours. What do you do. Well Watt Hours = Volts x Amp Hours. So to find the battery Amp Hour capacity all you need to know is the battery voltage and watt hours required. Amp Hours = Watt Hours / Battery Voltage = 1800 Watt Hours / 12 volts = 150 Amp Hours @ 12 volts.

OK lets forget solar and think vehicle alternator. Alternators are rated in Amps. I do not know how many amps your alternator produces but I can safely say at least 70 amps of charge current and likely more. You have to find that for yourself because I am not going to do your work. So if you use say that 360 watt hours each day, and we know the battery voltage is 12 volts then we know you would use 360 watt hours in a day / 12 volts is 30 Amp Hours. Taking into consideration battery charge efficiency of 85% your vehicle alternator wound take 30 Amp Hours / .85 / 70 amps = .5 hours or 30 minutes to recharge. Keep in mind you can go 2.5 days between charges if you have a 150 ah battery. If you went 2.5 days would require you to idle or drive roughly 90 minutes every 3 days.

Now do some rework. You want two 6 volt golf cart batteries. Golf cart batteries are rated around 200 to 240 Amp Hours. So that is a capacity of 12 volts x 200 amp hours = 2400 and 2880 watt hours respectively. If you use 360 watt hours per day you can go about 4 days to reach 50% discharge before having to idle or drive 2 hours to recharge.

So mow you have an idea of what it will take. Do you have the funds and room on your van to hold a 200 watt panel, and 15 amp MPPT controller. Just the panel and controller will cost you north of $400, plus another $250 for batteries. I seriously doubt you have room to mount two hundred watt of solar panel and would look pretty silly making you target for theft. You gotta decide. One other option I did not mention is a hybrid system where you use a small say 50 watt panel and a Battery Isolator. Panel would only supplement the alternator cutting fuel cost.



Nothing magical. It is a device that isolates your starting battery from the house batteries when discharging. So when you are parked without the engine running and watching TV the power comes from the house batteries only and will not run down the vehicle starting battery. When the engine is running will charge both vehicle starting and house batteries. The Electronic types allow you to select the correct voltage for the house batteries as the vehicle battery runs at a slightly higher voltage. A 70 amp unit runs about $35. You size then according to your vehicle alternator.

Wow I can't thank you enough for taking the time to explain all of that to me! A lot of knowledge gained, and a warning heeded haha. I hadn't even considered the fact that rolling around with a van decked out with solar gear would make me a pretty prime target for theft hah!

I'm speechless! I can't thank you enough for sharing your knowledge!