[smitty141]

I am in the process of wanting to ad some extra power to the inside of my van.. Here is what I would like to power.. 20" flat screen/dvd player (40 w max..18 w typical)
Maxxfan. 48 w on high, 6 w on low..
Laptop..42 w. on boot, less to run
phone ?
Coffee pot (small)
heated blanket..

Chances are not all will be running at the same time..

I was thinking 320 watts solar on the roof, with a 100 ah of so AGM battery with a 400 watt Pure Sine wave inverter..
Or, would a large house battery with a smart battery isolator do the trick.. Or am I way off on this..

Thanks Smitty

 

[Andre Jones]

I think either option would work depending upon how you use your vehicle. If driving around in case you drain the battery is not a big deal then the second option would be preferable. If you plan on setting up camp for 2-3 days at a time then the solar would be a must.

Even a small coffee maker can suck up a lot of juice, example: http://www.campingworld.com/shopping/item/black-decker-brew-n-go-coffee-maker/55673

800w as well as the heating blanket.

Depending how long you want to run, a bigger battery or bank of 100s may be necessary.

You likely will need to consider a beefier inverter, maybe 1000w if running the heating blanket and coffee pot is ever a likelihood.

 

[orton]

I have a 300 watt panel with a Morningstar MPPT solar controller that provides all the power I require. My house battery is a 255 amp-hr 8D AGM. The 1000 watt Magnum inverter will run a 600 watt (1140 watt actual) microwave. Use a propane stove. Either the microwave or the stove can be used to heat coffee water. I only turn on the inverter when I need 120 volt AC power. Left on overnight my inverter will use about 6% of the battery capacity without any 12o volt loads.

Suggest you use a DC heating pad instead of a AC blanket. Heat under is more comfortable than heat over. It also does not require the inverter to be turned on. I do not heat the van interior but stay warm with the heating pad. Problem is a cold head so balaclava is used. Since van is cold the refrigerator runs less so electrical usage is about the same.

First step is to buy a "Kill-a-Watt" meter for about $25. Run the 120 volt stuff you want in the van in your house to determine the actual amperage of each item. Because the inverter is about 85% efficient you must divide the AC loads by .85 to get the actual amperage draw. Make a similar list for the DC loads. Then estimate how many hours (or fractional hours) you will run each item each day. The total amp-hr consumption will tell you the battery size required. The battery size in amp-hrs should be at least double what you use each day. (50% discharge).

Next you need to determine how you are going to provide charging to return the battery to 100% SOC (state of charge) each day. There are multiple choices. Consider the efficiency of the charger.

The size of the inverter selected is determined by the total watts of all 120 volt items that you want to run at the same time. Doubt that a 400 watt inverter will run a coffee pot even without other items running.

Consider a DC TV so you do not need to run the inverter. Normally it is recommended that the solar wattage about match the battery amp-hr. In other words 300 watt panel used with a 300 amp-hr battery. I suspect you would want at least 200 amp-hrs of battery capacity. The 120 volt coffee pot is a major power user. Heat water on stove and use a coffee press? Will you cook with propane? Some like a single burner butane stove to avoid the power usage of a coffee pot.

 

[smitty141]

Suggest you use a DC heating pad instead of a AC blanket. Heat under is more comfortable than heat over. It also does not require the inverter to be turned on.
First step is to buy a "Kill-a-Watt" meter for about $25. Run the 120 volt stuff you want in the van in your house to determine the actual amperage of each item. Because the inverter is about 85% efficient you must divide the AC loads by .85 to get the actual amperage draw. Make a similar list for the DC loads. Then estimate how many hours (or fractional hours) you will run each item each day. The total amp-hr consumption will tell you the battery size required. The battery size in amp-hrs should be at least double what you use each day. (50% discharge).


The size of the inverter selected is determined by the total watts of all 120 volt items that you want to run at the same time. Doubt that a 400 watt inverter will run a coffee pot even without other items running.

Consider a DC TV so you do not need to run the inverter. .

Thanks, i did not think about a DC heating pad or TV.. I used a heating pad years ago when I drove a semi...

I am so new to solar I just don't want to have to buy twice. Should you buy the more expensive MPPT controller, or will the PWM work just fine?? The parts bill can add up fast!!

Thanks for any and all the help folks...

Smitty

 

[orton]

Space is limited on top of a van so anything that gets more output from the same space IMO has value. You also want a solar charger that can be programed to match your battery bank and one that gives a 3 stage charge.

Best solution for the TV is a book. There will never be a TV in my van. One of the reasons for camping is to escape the TV. I do have a tablet to connect to the internet.

 

[smitty141]

Space is limited on top of a van so anything that gets more output from the same space IMO has value. You also want a solar charger that can be programed to match your battery bank and one that gives a 3 stage charge.

Best solution for the TV is a book. There will never be a TV in my van. One of the reasons for camping is to escape the TV. I do have a tablet to connect to the internet.

The TV will never have a antenna, just a built-in DVD player for those rainy evening...

Thanks Smitty

 

[Hein]

320 watts solar with a MPPT controller sounds good. Along with that I would recommend two 12V group 27 AGM batteries for a total of ~210 Ah. Also a little bit larger 600 watt inverter with a built in (or stand alone) shore power charger and the ability to charge with the alternator via a combiner or Orton's dual inverter system.

To get the most utilization and life from the batteries, you need to take advantage of all 3 charging sources: solar, shore power, alternator.

Your coffee maker is the largest 120V load. There are small 4 cup and single serve 600watt models available.

 

[orton]

Need to get up on my soap box again.

Depending on your climate and electrical usage the 300 watt panel can provide all the power required without any need for charging from shore or the alternator. Mine does that. I do have two other methods of charging for backups. Can use real 120 volt AC shore power or "shore power" from a vehicle powered pure sine inverter. A selector switch selects the source used.

The advantages of using a second vehicle powered inverter instead of a direct house battery to vehicle battery connection are:

1. The house battery is always charged with a 3 stage (bulk,absorb,float) charge.
2. A correct charge profile can be programed into the charger that matches your house battery requirements.
3. Two batteries that are different size, type, age, mfg. date or brand are not connected together for charging.
4. 120 volt AC power is available while you drive for other purposes. I heat my shower water electrically or can run an electric baseboard air heater in back of van.
5. 14/3 cord for AC is used to get power from front of van to rear mounted charger instead of heavy 12 volt cable.
6. Eliminates the connecting relay.
7. Allows the house 12 volt system to be completely independent of the vehicle electrical system. I do not use the chassis as a ground for the house system. Two wires to each load.
8. Limits the draw on the alternator. Amount of power from the vehicle is limited by the size of the vehicle inverter.

Disadvantages:

1. Can not easily connect house battery to vehicle battery for vehicle starting.
2. Slightly higher cost.

I also prefer one 4D or 8D house battery instead of multiple batteries. Simpler installation with fewer connections and less space required. One battery may cost more but installation costs are less. Some comment about the weight at installation. That has not been a problem and you only do that once.
Same reasons for using one solar panel instead of multiple panels. No need for a roof rack or combiner box with multiple wires. Just two wires between panel and solar controller. One panel has the disadvantage of less power if portion of panel is shaded. That has not been a problem for my installation.

 

[xckeefe12]

What device do people use to interface with the alternator? I have been reading a bit but there does not seem to be one tried and true solution. Seems like a basic isolator will only charge the battery to 70% since it's at 13.7V and not 14.6V

I would like to start with charging a 200ah house battery with the alternator, then integrate 200W of solar later on

Any help is appreciated!

 

[Sprinter54]

I'm planning to install Nations alternator. I do have Panasonic 325w solar panel and 500ahr LifePO4 battery already installed.
Idea is to charge battery bank as fast as possible from Nations alternator.
so far have no idea how to achieve it.

 

[Michael Ophus]

What device do people use to interface with the alternator? I have been reading a bit but there does not seem to be one tried and true solution. Seems like a basic isolator will only charge the battery to 70% since it's at 13.7V and not 14.6V

I would like to start with charging a 200ah house battery with the alternator, then integrate 200W of solar later on

Any help is appreciated!

this is one idea and its what i am using, also they make a high amp charge model http://www.sterling-power-usa.com/B...probattc-batterytobatterycharger12vto12v.aspx

 

[smitty141]

Can anyone steer me to a quality MTTP controller for $200 or less? There are so many and I am confused.. Here is a link to the panels I bought.. So you Tech guys can see all the spec's..

http://www.grapesolar.com/docs/GS-S-160-Fab8.pdf

I do believe a 30 amp will be enough... But is there any negative issues by going with a 40 amp??

Thanks Smitty

 

[orton]

I use a Morningstar MPPT Sunsaver 15 amp with a single 300 watt high voltage panel. $228 on Ebay. If I recall correctly the controller can be used with up to 400 watts of solar.

Some will say it is to small for a 300 watt panel. 300 watts/14 volts = 21.5 amps. Assuming the panel is 80% efficient not being correctly oriented to the sun and it is warmer than the test rating then maximum amperage would be 21.5 x .80 = 17.2 amps. Any charging lost would only be around noon. The lost amount of charging would just be the small amount over 15 amps only around noon. Very small % of all the total charging. Had this discussion with the Morningstar tech. and he explained how little is lost.

System works fine and always gets me back to 100% SOC before noon on sunny day. Even on overcast days it usually gets back to 100%. Major draw is the refrigerator.

 

[Hein]

+1 for Morningstar. We also have the Sunsaver MPPT controller with 200 watts worth of panels. Works great. We added the remote display which brought the total price up a bit. The new ProStar controllers are higher amperage (25 and 40) and available with and without displays:

http://www.morningstarcorp.com/products/prostar-mppt/

 

[Johnnydanger]

I did the house power charging with only an ACR for a year and a half. It worked merely okay. The issue is that I rarely drive long enough to get a nice full charge on the house battery ever, plus being a 105ah AGM I'd suck it pretty low on a dark winter day with lighting, electric blanket at night, USB/12V accessories. Needless to say the alternator would rarely get the house battery to take a full charge. You could literally drive all day, then upon getting home plug in a battery charger at 2amp trickle and it would still charge for another 5+ hours.

Orton is right about battery health and charge: Deep Cycle AGM have different charging requirements than a lead acid automotive battery. They like staying topped up, they like a multi-stage charge, etc. Short bursts of 20+ amps off the alternator at 14.2V just doesn't cut it. It works, but not optimally and in effect leaves you with a battery that is always 20-30% down on charge.

Over a year and a half the battery began to show signs of sulfating. You could charge it up with a trickle charger and it would say 100% and 12.7V, but as soon as you put any load on it it would quickly fall to 12.5 or less. My battery shop has a de-sulfating process that they ran on my AGM and bam, it's good as new now. Holds 12.8V and has serious CCA—more than original surprisingly. I then added 200W of flexible solar taped to the roof. Now I'm laughing. Solar may be the single best electrical upgrade I've done. With moderate sun I can power my Engel 47L fridge, MaxxFan, and USB charging all day with no cumulative draw on the battery, plus the multistage charger gives the battery a nice solid charge. With my 105ah AGM, 200W of solar, and fridge/fan/webasto heater/USB/lights, I am fully charged everyday by around 10 or 11am (in the summer). When the sun goes down my battery goes from 12.85V down to about 12.45ish overnight (the lowest I've seen thus far is 12.3 in the morning when I didn't get good sun the day before). This is night and day vs. my ACR only setup which would regularly see 12.7 fall to 11.9ish overnight with the same or less loads.

Solar for the win. Even a cheap setup like my Amazon special homebuilt setup makes a huge difference. House battery fully charges on it's own everyday without thinking about it. The multi-stage solar charge controller gives a much better charge than just applying alternator amperage to it. Running the fridge 24/7 is now a viable option for multi-day camping trips. It's cheap. My 200W system was $600 all in. If I had gone for hard panels vs the flexible ones it would have been more like $450-500.

 

[swellguy]

I'm planning to install Nations alternator. I do have Panasonic 325w solar panel and 500ahr LifePO4 battery already installed.
Idea is to charge battery bank as fast as possible from Nations alternator.
so far have no idea how to achieve it.

How do you like the LifePO4 batteries? Man, that's a big pack!

 

[swellguy]

I did the house power charging with only an ACR for a year and a half. It worked merely okay. The issue is that I rarely drive long enough to get a nice full charge on the house battery ever, plus being a 105ah AGM I'd suck it pretty low on a dark winter day with lighting, electric blanket at night, USB/12V accessories. Needless to say the alternator would rarely get the house battery to take a full charge. You could literally drive all day, then upon getting home plug in a battery charger at 2amp trickle and it would still charge for another 5+ hours.

Orton is right about battery health and charge: Deep Cycle AGM have different charging requirements than a lead acid automotive battery. They like staying topped up, they like a multi-stage charge, etc. Short bursts of 20+ amps off the alternator at 14.2V just doesn't cut it. It works, but not optimally and in effect leaves you with a battery that is always 20-30% down on charge.

Over a year and a half the battery began to show signs of sulfating. You could charge it up with a trickle charger and it would say 100% and 12.7V, but as soon as you put any load on it it would quickly fall to 12.5 or less. My battery shop has a de-sulfating process that they ran on my AGM and bam, it's good as new now. Holds 12.8V and has serious CCA—more than original surprisingly. I then added 200W of flexible solar taped to the roof. Now I'm laughing. Solar may be the single best electrical upgrade I've done. With moderate sun I can power my Engel 47L fridge, MaxxFan, and USB charging all day with no cumulative draw on the battery, plus the multistage charger gives the battery a nice solid charge. With my 105ah AGM, 200W of solar, and fridge/fan/webasto heater/USB/lights, I am fully charged everyday by around 10 or 11am (in the summer). When the sun goes down my battery goes from 12.85V down to about 12.45ish overnight (the lowest I've seen thus far is 12.3 in the morning when I didn't get good sun the day before). This is night and day vs. my ACR only setup which would regularly see 12.7 fall to 11.9ish overnight with the same or less loads.

Solar for the win. Even a cheap setup like my Amazon special homebuilt setup makes a huge difference. House battery fully charges on it's own everyday without thinking about it. The multi-stage solar charge controller gives a much better charge than just applying alternator amperage to it. Running the fridge 24/7 is now a viable option for multi-day camping trips. It's cheap. My 200W system was $600 all in. If I had gone for hard panels vs the flexible ones it would have been more like $450-500.

Great write up! I have a 200aH setup with a Hein battery pack (2 group 27 batteries), Sterling 60A charger and 20A solar MPPT charger. Have not hooked panels up yet, but have a 100W flexible one to start. Hope I can get away with only 200W. If you double-back taped the panels to the roof, do you ever see the tape separating esp. in hot sunny conditions? I have a dark paint job think this might be a problem. Are you concerned at all about security of the panels? Was thinking about something more hard-mounted to discourage theft. Cool setup, glad someone did it before me.

 

[Sprinter54]

How do you like the LifePO4 batteries? Man, that's a big pack!

I do not know yet. Van is in upfitter shop 700 miles away.

 

[BabyBuffy]

I am planning to purchase a LWB Transit van and embark on a DIY camper conversion, still trying to decide between HR or MR. I prefer MR but my wife thinks standing up is high priority and is lobbying for HR. My intentions are modest compared most DIY conversions I've read about. For instance, no kitchen, toilet, or shower wanted. Primarily a bed, plenty of storage for camping gear, good lighting, sound, DVD watching capability, and refrigeration.

Despite spending a number of weeks so far researching various aspects only recently came to discover the medium and high versions are apparently unobtainable with cargo doors (which we drastically prefer over a slider). Is there any way to get around this?

Also, am considering Lithium Ion battery as the house battery. They are hugely more expensive but I love the purported advantages and am willing to bear the cost unless I'm persuaded it isn't such a good idea for reasons I'm unaware of. (I also intend to install solar panels.)

 

[Michael Ophus]

i had thought about lithium but its still largely unproven technology, cars are still catching fire that have not been in an accident! from what i have heard, if you are going to do it, buy the best! (if you can afford it?) http://www.westmarine.com/buy/mastervolt--ultra-series-lithium-ion-batteries--P014994321?recordNum=4