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Getting Closer to the Final Battery Bank Modifications

It’s amazing how much research one can do about a subject and still completely miss the most obviously solution to a problem. My battery bank project has taught me an important lesson. Yes, it’s nice to offer a ‘tah-dah!’ post to readers with no build up, but the build up posts provide the opportunity for discussion that could change the outcome.

Reader Carl left an interesting comment on my last post. Boiling the comment down to its essence, he asked me, “Why don’t you just plug your RV into your inverter? This way, all your outlets will be live off shore power and you won’t have to run that 120V wiring to a single outlet.”

I can do that?!

As it turns out, I can! I did some research and the end result is that you can plug an RV power cable into an inverter just like you plug it into a generator or a shore power outlet. The caveat is wattage of the inverter and the size of the battery bank determine what can be left on when you’re running off the inverter.

Generally, when you plug your RV into an inverter, you want to turn off the converter, the microwave, the AC, the fridge, and the water heater if is electric.

My fridge’s default mode is propane and my water heater runs on propane, so that leaves the other three.

Now, I know there are transfer switches and all manner of mods to automatically transfer over to the inverter, but I don’t have the electrical gumption to dig into my established power grid, never mind the financial outlay. So I’ll be using the ‘shut off the breakers’ method of electrical management to power my RV from my inverter.

So instead of running 120V wiring from the front to the back of the rig in a straight line, I’ll be running it diagonally to the shore power cord storage compartment. I think I may have a route that will let me do this through the underbelly rather than under the rig. In theory, it would be easiest to bring my shore power cord to the inverter, but the stupid location of my battery bank precludes that option.

There is another thorn in this project because of my battery bank’s stupid location. Since there is no compartment next to it, I have to put the inverter up in the living room. So 12V wiring has to go up into the living room and then the 120V wiring has to come back down into the compartment to be taken to the back of the rig.

That said, the compartment where my batteries are located is huge and the batteries are well vented. I am considering putting the inverter in some sort of housing that would be sealed from the rest of the compartment but still ventable to the outside. The batteries themselves are vented to the outside, too.

I think that this would be sufficient to reduce the risk of the hydrogen emitted from the batteries from eating the inside of my inverter or, worse, meeting a spark that would cause a catastrophic boom. I really can’t see how this option is any more dangerous than having the inverter above the battery banks since hydrogen travels upwards.

If there’s still time after these issues are resolved, my mother and I will pass the cabling for the monitor and the remote inverter starter to the study from under the rig. Otherwise, they will go into the living room.

A reader emailed this evening to say that the monitor should be as close to the batteries as possible, but the Xantrex connection kit has 20′ of cabling and the customer service tech confirmed that this distance is acceptable. I’d like the starter and monitor in the study for convenience’s sake, but, really, it wouldn’t kill me to get up a couple of times a day and walk less than 40′ round trip to go check out the state of my batteries. 🙂

Before I get any concerned comments about whether or not I have enough battery capacity to run my rig off my inverter, I’m in the market for new batteries! The next few months will be a great trial run to determine just how much battery capacity I really need.

Sunday’s task list is gigantic and I hope we can get everything done!

14 thoughts on “Getting Closer to the Final Battery Bank Modifications”

  1. Add your battery charging system to things you cannot run off the inverter! In theory this is a good idea but you will have to be aware of all the things that will quickly drain your batteries that may be plugged in or connected to the AC. Some of these things draw a small amount of power even if they are not turned on.

    Something like a Kill A Watt would make this check easy and would alert you to excessive battery drain.

  3. Croft, the battery charging system is the converter. That’s the first thing that all the advice says to shut off.

    I’ve got a Kill-a-Watt on order for pick up in the States this fall.

    Besides the office stuff, the only thing that’s plugged into AC all the time is my toaster. It’s the office stuff that will be interesting to monitor.

  4. Hi Rae:
    I am never buying a Triple-E again. When they installed the windows at the factory in the Triple-E Regency Class-C that I bought brand new they were not very careful and scraped the butyl sealer that is supposed to be between the outside window frame and the side wall.

    Now the sealer was below the side wall not sealing anything. Every window leaked and all the side walls delaminated under the windows in just a few years.

    A minor quibble with Triple Es, don’t know if it still applies, they used a friction catch for the cupboards which I found very noisy to open and close. I prefer the catches with the small button at the bottom of the door, very quiet once you get used to the way they work.

    Also the friction catches sometimes popped open while traveling while the push button catches never did.

    Still not caught up to the present on your blog, there seem to be more issues, I hope it all works out OK.

    Carl

  6. As those catches get bent out of shape, I have been replacing them with the magnetic type. They are easy to install but sometimes I need two of them for heavier doors.

    That “link” I gave you first is funny. It is the balance of one of my investment accounts that I had previously copy and pasted. That’s what happens when you don’t pay attention. (Note from Rae: I have removed that information from your previous comment, but I thought that this was too funny to delete!)

  7. I find magnets don’t hold well enough.

    It’s interesting that none of my overhead cabinets in the living room and study have catches.

  8. Hi Rae:
    My post on the ‘whole house inverter’ (I like that) was long enough so I did not go into the complications of all the AC breakers to be turned off when connecting the inverter this way. You are so clever I knew you were going to figure that out and see, you already did.

    I am still reading your older blogs and cannot understand why your house battery does not get a full charge from the engine alternator while you are driving. My house battery is always full after 3 to 4 hours driving, most of the time it takes less.

    When you have time can you do me a favour and measure the voltage across your house battery with the engine running and post the numbers here.

    Please take 2 measurements, one with the fridge completely off, the other with the fridge on 12 Volts. For these measurements could you please take them when the solar monitor confirms that the house battery is full but with the solar panel and any other chargers turned off.

    Measure the voltages with the multimeter probes right on the house battery terminals.

    I am trying to determine if there is a reason for your house battery to take so long to recover even when you drive for many hours.

    Also you are burning through house batteries at an alarming rate, mine last 7 or more years.

    I know that this is less of a problem now that you have solar panels.

    In your posts you often mention having to go FHU (Full Hook Up, that is funny I think you invented it) for your house battery to be fully charged and I never have to do that even when I spend a month or more on the road. BTW I still don’t have a solar panel but I am also a tourist, not a full-timer.

    I am only up to the April 2011 blogs now so this may no longer be an issue.
    Carl

    • Carl, I have long days on the road, but I’m actually not getting in that much mileage. So that’s probably why my batteries aren’t charging. The last time I did the readings with the multimetre, I was getting 13.3V with the engine running, just like I do when I’m plugged into shore power.

      I know that four years is actually an average lifetime for RV batteries.

      I’m not sure if mine are done or not yet; the monitor will tell me that. But even if they aren’t, I’d like to get new ones with more amp hours.

      I did not invent the term FHU, but I wish I had! 😀

      I’m pretty sure that you are driving longer distances in one shot than I am.

  9. I understand the points that you raised.

    13.3 V is actually a bit low and lead acid batteries need a short charge of 15V once per month to extend their lifetime.

    Average lifespan is just that, RV batteries need more care than the average RV owner usually provides, you are definitely not an average RV owner, you take excellent care of all your other RV systems.

    The modifications that I have used in my RVs would require some wiring changes which may not be cost effective, $100 to $200 plus changes to charging practices.

    Have read up to your toad loss and axle repairs, so glad that everything worked out for you so far (May 2012).

    I will continue to follow your adventures with interest. Even though I have been boondocking since we drove a delivery van to South America in the early 1970’s from Canada and still wilderness camp most of the time when riding my Cruiser I have learned a lot from your blog.

    Keep up the good work!
    Carl

    • Carl, I was rough on my batteries at the beginning, before I understood how to take care of them. Plus, they have been through some severe weather extremes. So if they’re due to be replaced, I won’t kick myself.

      I’ve never gotten my batteries above a 14V charge.

      The rest of the blog is boring. You can stop where you are. 😉

      Thanks for sharing the journey.

  10. Before I get any concerned comments about whether or not I have enough battery capacity to run my rig off my inverter, I’m in the market for new batteries! The next few months will be a great trial run to determine just how much battery capacity I really need.

    The question is not IF you have enough battery capacity to run off the inverter it is who long you will be able to run.
    IF you increase the amp hours of your battery bank you will need to think about adding to your solar array also. I am guessing that you are now charging a 220ah bank using 150W of solar. The usual rule of thumb is 1W per 1ah to fully charge the battery bank.

    • Ed, to me, the ‘if’ and the ‘how long’ kind of blur together.

      My battery bank has somewhere between 90 to 120 usable amp hours. Probably closer to the former since the 150W solar panel has no trouble fully charging batteries on a moderately sunny day. At this point, I don’t see myself getting another solar panel before increasing my amp hours since I’m obviously not running the solar panel at capacity.

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