RV Upgrade Plans

Buzzy
Buzzy Registered Users Posts: 3 ✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
Hi all, I've been browsing this forum for a few months now (getting educated I hope) but this is my first post.

I bought a used 2010 Coleman E3 popup last year and opted for a portable system. Now, after much research, I realize that some upgrades and adjustments are necessary and am looking for feedback on my plans.

The E3 came with 2 6V Interstate batteries rated at 232 AH (now approx 4 years old.) The panel I bought are 100W/17.5V/5.44A. I upgraded the charge controller to a Sunsaver 10L but kept it mounted near the panels (there's about 25 ft of 12 AWT from from the batteries.) I like the portable panels because I prefer to camp in the shade.

For the most part I am a light power user (lights, waterpump, phone charging etc.) but lately I have taken to using the E3 as a mobile office and bring my laptop (software, ecommerce, etc. developer here) For that, I hastily purchased a $40 300 Watt inverter that runs from a 12 V outlet I've added. I think I will eventually purchase satellite internet and add a router to the camper.

I've killed some batteries on previous campers, so now I do my best to keep them maintained (charge them every month, check electrolyte levels, etc.)

There's my background, now for my plan:
  1. Purchase and install a Trimetric TM2030A monitor w/100A shunt (that shunt was recommended for a system my size) I am going to do this first so I can make an attempt to measure the effect of the other changes below
  2. Move the controller closer to the battery bank (within 1 or 2 feet)
  3. Upgrade the majority of the panel to controller wiring to 25ft of 8 AWG (I think I will need this should I add another 100 watts of solar to bring my charge ratio to 5%) I estimated voltage drop to -0.35V at 11 amps using an online calculator
  4. Use 1/0 for controller to battery wiring
  5. Purchase and install a Morningstar SureSine 300 inverter, run 15+/- feet of 1/0 welding wire between inverter and batteries
  6. If when I add watts, I'll upgrade the controller (right now the Bogart SC2030 is at the top of that list)

I hope I've done my homework correctly.

My biggest concern is the inverter. I think I need to install this inside the trailer, approx 10 to 15 feet from the batteries. My current inverter will charge my laptop when the laptop is closed, but shuts down whenever I open the screen. (Yes, likely due to inadequate wiring for the distance from the batteries.) Looking at a Morningstar wiring chart (attached,) looks like 17ft of 1/0 will keep voltage drop below 2% at 60 amps. Does this look like the appropriate thing to do wire-wise? I will also run 14 AWG (or larger?) from the inverter to a single AC outlet (about 3 or 4 feet.)

My laptop's power adaptor is rated at 85W, 4.5A. I imagine the router and satellite receiver will be less than this.

Does anything else in my plan seem inadequate or way overkill?

Thanks in advance
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: RV Upgrade Plans

    Welcome to the forum.

    You've got 232 Amp hours of battery and a maximum of 10 Amps through the SunSaver. Right there is a problem without other external recharging: the rate is <5%. You can't add more panels without a bigger controller. You need about twice as much as you've got for full solar charging.

    Get a Kill-A-Watt and measure the power used by laptop and satellite. My laptop uses 12 Watts, he sat system uses 50.

    Ideally the inverter, regardless of size, should be as close to the batteries as possible. You want the long wire runs to be at the higher output Voltage, not the lower input Voltage.
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  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    #3
    Re: RV Upgrade Plans

    What Cariboocoot said. Not enough panel for your batteries.

    232 ah battery bank @ 10% charge rate = 23.2 amps

    23.2 amps x 17.5V = 406W of panel needed

    This is a bit simplified, but it'll get you in the ballpark.

    For 23.3 amps you'd need a charge controller rated at 30 amps minimum. Lots of options in that range. Consider Midnite's Kid controller (MPPT), and get their Whiz Bang battery meter instead of the Trimetric. I'm considering replacing my Morningstar TS-45 with this combo. The Morningstar is OK, but not easily programmable, and I'd prefer an MPPT controller, which opens up a lot more options and is generally more efficient than PWM controllers, especially in winter.

    I was looking at the Trimetric, but the lack of temperature compensation in the battery amp-hour reading is a problem since I'm using my system year round.

    Any idea how well the previous owner treated your batteries? Have you tested them?

    ETA: The Morningstar Suresine has good reviews here (and elsewhere). I plan on replacing my cheapo inverters with one. If you're just running lights, a 12V RV pump, and a laptop, you may not need a true sine inverter, but it won't hurt.
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  • Buzzy
    Buzzy Registered Users Posts: 3 ✭
    #4
    Re: RV Upgrade Plans
    Cariboocoot wrote: »
    Welcome to the forum.

    You've got 232 Amp hours of battery and a maximum of 10 Amps through the SunSaver. Right there is a problem without other external recharging: the rate is <5%. You can't add more panels without a bigger controller. You need about twice as much as you've got for full solar charging.

    Get a Kill-A-Watt and measure the power used by laptop and satellite. My laptop uses 12 Watts, he sat system uses 50.

    Ideally the inverter, regardless of size, should be as close to the batteries as possible. You want the long wire runs to be at the higher output Voltage, not the lower input Voltage.

    Cariboocoot -- thx. I do recognize that I am below the 5% recommended charge rate and would have to upgrade the controller if I add more panels. I've read that a bunch in this forum but I'm curious, where does that charge rate recommendation come from?

    As far as the inverter, I wanted to mount it inside the trailer to keep it dry and less likely to be stolen, but will see if I can get it in something weather-tight and theft-proof on the tongue. How should I size the inverter to AC component wiring?
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  • Buzzy
    Buzzy Registered Users Posts: 3 ✭
    #5
    Re: RV Upgrade Plans
    Plowman wrote: »
    What Cariboocoot said. Not enough panel for your batteries.

    232 ah battery bank @ 10% charge rate = 23.2 amps

    23.2 amps x 17.5V = 406W of panel needed

    This is a bit simplified, but it'll get you in the ballpark.

    For 23.3 amps you'd need a charge controller rated at 30 amps minimum. Lots of options in that range. Consider Midnite's Kid controller (MPPT), and get their Whiz Bang battery meter instead of the Trimetric. I'm considering replacing my Morningstar TS-45 with this combo. The Morningstar is OK, but not easily programmable, and I'd prefer an MPPT controller, which opens up a lot more options and is generally more efficient than PWM controllers, especially in winter.

    I was looking at the Trimetric, but the lack of temperature compensation in the battery amp-hour reading is a problem since I'm using my system year round.

    Any idea how well the previous owner treated your batteries? Have you tested them?

    ETA: The Morningstar Suresine has good reviews here (and elsewhere). I plan on replacing my cheapo inverters with one. If you're just running lights, a 12V RV pump, and a laptop, you may not need a true sine inverter, but it won't hurt.

    Plowman -- I'm more or less a weekender with 2 or so longer trips so was going by the 5% recommendation that I've read here. Same question as I asked Cariboocoot, what is the calculation behind this recommendation?

    The previous owner told me he charged the batteries off the built in 3 stage while driving to camp. I give them a monthly charge (year round) with a black and decker charger. After resting, I typically see 12.8V on a multimeter. I'm not sure when they'll need to be replaced. They're Interstates and I don't love them, mostly because they seem to weep quite a bit and require an awful lot of cleaning. Right now Crowns or Trojans are on my short list.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: RV Upgrade Plans

    The 5% minimum net charge rate comes from battery manufacturers. Practically all of them who bother to mention it in fact.

    Now keep in mind this is a charge rate, not a maintenance rate. When you have other charge source available such as the vehicle alternator (or shore power or a generator) used regularly you don't have to expect the full rate from solar; it can keep the batteries up and/or extend range at less than 5% current.

    So depending on how long between such charging and how much power you use it's entirely possible for an RV to have a small amount of PV that will suffice. The longer the batteries go without a full charge, however, the shorter the lifespan. This is why the formula for RV PV is usually "as much panel as you can fit" (owing to space limitations).
    As far as the inverter, I wanted to mount it inside the trailer to keep it dry and less likely to be stolen, but will see if I can get it in something weather-tight and theft-proof on the tongue. How should I size the inverter to AC component wiring?

    If you need the inverter to be far from the batteries you can have trouble even with large wires. The 300 Watt inverter at maximum power and nominal Voltage will pull 25 Amps, which needs 10 AWG just to handle the current. If it is 15 feet from the batteries then the V-drop would be over 6% and you definitely feel the effect. Your plan to use 1/0 is wise, but I think you'll find it doesn't fit in the MS 300 BATT terminals so some transitioning would be needed.

    The AC output side is easy, because the Voltage is fixed at 115 and the current maximum is 2.6 Amps continuous. Standard 14 AWG will handle that over a distance of 200 feet! Not likely you'll have any wire runs that long, eh?
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  • scrubjaysnest
    scrubjaysnest Solar Expert Posts: 175 ✭✭✭
    #7
    Re: RV Upgrade Plans

    I learned the hard way, the minimum inverter to charge the laptop while using it is 400 watt.
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  • RandomJoe
    RandomJoe Solar Expert Posts: 472 ✭✭✭
    #8
    Re: RV Upgrade Plans
    scrubjaysnest wrote: »
    I learned the hard way, the minimum inverter to charge the laptop while using it is 400 watt.

    You have piqued my curiosity - what happened? What laptop? That's an awful lot of power for a laptop to require!

    I'm sure there are some large "desktop replacement" laptops that require that kind of power, but most laptops should be considerably lower. For that matter, even my 27" iMac has a power supply with max wattage rating of 400W but I've never seen it use more than 120W or so. The power adapters for my laptops are rated for far less - Macbook Pro 85W, Macbook Air 60W, Eee PC a mere 32W!
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  • scrubjaysnest
    scrubjaysnest Solar Expert Posts: 175 ✭✭✭
    #9
    Re: RV Upgrade Plans

    The laptop is a Toshiba 105a. Tried on a 200 watt and the 200W inverter internal fuse went away. I.ve 10 awg feeding the 12v cig lighter style outlet in the RV. With the 400 watt inverter, my laptop running and DW's netbook on charge the current draw is 6.35 amps.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
    Re: RV Upgrade Plans
    scrubjaysnest wrote: »
    The laptop is a Toshiba 105a. Tried on a 200 watt and the 200W inverter internal fuse went away. I.ve 10 awg feeding the 12v cig lighter style outlet in the RV. With the 400 watt inverter, my laptop running and DW's netbook on charge the current draw is 6.35 amps.

    6.35 Amps @ 12 VDC is 76 Watts.
    Probably that 200 Watt inverter was not a good one.
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  • scrubjaysnest
    scrubjaysnest Solar Expert Posts: 175 ✭✭✭
    #11
    Re: RV Upgrade Plans

    You could be right; a friend of mine ran into a similar problem when using his lap top in the car while geocaching and suggested the 400 watt when I explained the problem.
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  • ZoNiE
    ZoNiE Solar Expert Posts: 100 ✭✭
    #12
    Re: RV Upgrade Plans

    Ditch the cigar outlet. Hardwire your inverter with proper fusing.
    That outlet will give you a lot of Vdrop as well. They were never intended to be used for power, they just became the de-facto standard because cars all had them. I'd only use them to plug a fan or a phone charger into, and they suck for that too.
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  • Reed
    Reed Solar Expert Posts: 55 ✭✭
    #13
    Re: RV Upgrade Plans

    Those "Cigar chargers" or 12 v outlets as the salesmen prefer to call them do work well for phone, GPS, and fans. We have eight of them about the interior of the 5th wheel and in the "basement" These only draw tenths of amps at 12 V and are well suited for these purposes. They are rated at 10 amps (12 V) or about 120 W. Our inverter is 4 kW and doubt that it would work well on a "cigar charger". Inverter works off the 48 V nominal battery bank.
    Reed and Elaine
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  • scrubjaysnest
    scrubjaysnest Solar Expert Posts: 175 ✭✭✭
    #14
    Re: RV Upgrade Plans
    ZoNiE wrote: »
    Ditch the cigar outlet. Hardwire your inverter with proper fusing.
    That outlet will give you a lot of Vdrop as well. They were never intended to be used for power, they just became the de-facto standard because cars all had them. I'd only use them to plug a fan or a phone charger into, and they suck for that too.
    Not practical the way we use the inverter. It stays with the laptop and can be used in the tow vehicle also. The outlet we use in the camper has been upgraded to 10 AWG.
    The 400 watt inverter actually uses less power then the standard cigarette lighter.

    Anther problem with the location of the batteries in our camper, it prevents the installation of larger inverter without looong runs of very large wire. Unlike most RV's that have the batteries located on the tongue or near the front ours are at the very back. Moving them to the front would be a thought but our already high tongue weight would go up about another 130# or so putting the tongue weight near the 700 # range. This would require new spring bars for the WDH which would increase the axle loading. This in turn would require a reduction in supplies unless things could be balanced by loading about a 100 or so pounds in the area that the batteries currently occupy.
    Nothing is easy.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #15
    Re: RV Upgrade Plans

    I can run 2 laptops and charge 3 of our 4 cell phones all at the same time from my 150 MSW inverter. The 4th cell phone puts it into overload. Last time we needed to do that was 3 nights in Yellowstone. We never got back into camp in time to run the genset within allowed hours and kept forgetting to charge the phones when we were in the truck.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #16
    Re: RV Upgrade Plans
    scrubjaysnest wrote: »
    Anther problem with the location of the batteries in our camper, it prevents the installation of larger inverter without looong runs of very large wire..
    You could put the inverter in the back with the batteries and run tiny AC wires... just a thought.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • opticalmike
    opticalmike Registered Users Posts: 20 ✭✭
    #17
    Re: RV Upgrade Plans

    That's what I did. 4 t105's and a 3 kW inverter as well as kid and whiz bang jr all up front on our Fiver. I then wired a plug onto some housewire and drilled some holes to run a few recepticals around the trailer.One for the microwave and another behind the Tv dvd entertainment system. I use 4 into 1 gang adapters to give me a total of 8 A/C recepticals. The 2 runs of house wire are distributed via a single junction box on the ceiling inside the storage area (basement) The inverter has a wireless key fob to turn off and on. I have 6, 85 watt panels wired series parallel on the roof...3 strings of 2 panels terminated at a midnite combiner box. The entire trailer is retrofitted with LED lights. No generator. The next project is a new digital thermostat for the furnace, and possibly a more efficient furnace motor.
    Any one with direct experience with a furnace motor upgrade please chirp in.
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