New charger or go inverter?

Split from General / Technical for discussion of anything electrical, electronic... 12v, Inverter, Satellite, Headlights, flashlights etc.
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Manitou
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New charger or go inverter?

Post by Manitou »

It seems to me that inverter prices have come down far enough (especially if you don't mind taking a chance on some unknown brand from china) that you could replace the existing charger with an inverter/charger combo. This level of electrical is just a bit over my head though. From what I've gathered:
1) put inverter close to the battery bank
2) wire the 110 out from the inverter to the existing charger/12v converter panel
3) something about a "sub panel" for A/C and microwave and maybe fridge? Could an inverter not be sized big enough to run these too? How much juice does that AC really take? Maybe a "hard start capacitor" to help kick it off?

related topics:
(a) remove battery slider (that's rusting anyway) and fit 3 AGM batteries in place of the existing 2 lead 27's
(b) more solar? flexible panels attached to the a/c and thule cargo box covers?
(c) solar charge controller? I'm unclear how to wire the solar at all. I understand the existing panel was small enough that it was simple in comparison.

covered a lot.. maybe too much for one post.
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Blue~Go
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Re: New charger or go inverter?

Post by Blue~Go »

Heh, you did cover a lot of ground! I wonder if it might be good if you edited the title to something like "coach charging/electrical system upgrade."I can understand how it gets "out of control" for one thread though: Because you really need to look at the system as a whole, so you can plan it intelligently. Thus.... HUGE.

I've been thinking about these things for years (mostly on boats) and doing some of them.... and I still get confused sometimes. I'm also not an electrical pro, although I have re-done my small boat (simpler than a Chinook, which is actually just about as complicated as a large RV).

Sometimes it helps to read through some already published material, such as that by Jack Mayer. I also find that the boating world is sometimes a step ahead of the RV world, although the systems are very similar.

So basically I think it starts with figuring out what you want your system to do for you. It's sort of like if a customer comes into a sporting goods store (and I work there) and asks me "What is the best raincoat?" Well.... how are you going to use it? If it's for a 6-month backpacking expedition to SE Alaska, a city/opera tour in Italy with porters for your bags, or a 3-hour ball game and then throw it in the dumpster? Those would be three very different "best" raincoats. The last one might be a contractor trash bag with holes poked for the arms :lol:

Our Chinooks (indeed, many RV's) look to have been designed basically to drive from electrical hookup to electrical hookup (or to run the generator a lot). And if this is how it is used, any upgrades would be very different than, say, someone (like me) who likes to boondock. I also think it's worth looking at some of the "assumptions" to see if they fit your scenario. For example, in my case, I virtually never used a microwave at home (even when it was easy, electrically), and I really had no desire to do so in the coach. I also don't tend to watch TV. So for me, those things are not a priority. Neither is keeping the rig up to the highest possible re-sale value for a mythical, "typical" RV-er. I save and store carefully anything that can easily be put back, and I make sure my mods are of good quality, but other than that, I bought the rig for me, not future owners. However, everyone is different that way.

Back to your use pattern: I think that's the most important thing to try to figure out first. Sometimes that's hard, as you don't know how you will use it until you use it, and it's a "vicious cycle" that way. Other times you do know. Essentially you should to at least try to figure that out.

For example, my use case:

1) I travel a lot, but also want to be able to stay in one place for up to two weeks.
2) I like to boondock with no hookups.
3) I like peace and quiet.
4) I don't want to have to park in the sun 24/7 at all times.
5) I'm a night owl (so will use battery power when the sun is not up).
6) Air-conditioning (coach) and microwave are not important to me.
7) My electrical needs are modest EXCEPT I must have my laptop/wi-fi hotspot, and be able to charge various AA batteries for camera, etc. I also like to be able to run power tools from time to time (away from hookups as I don't like to make noise in campgrounds).
7.5) That said, I would really like to be able to replace the 3-way refrigerator with an efficient 12-volt model (even efficient electrical refrigerators are energy hogs, especially in warm climates).
8) It's important to me to understand my whole system and know it is done right (proper over-current protection, plenty adequate wire sizes, labeling, etc.)
9) I don't mind making mods, but want to keep the rig looking good.
10) I don't mind spending money as long as I enjoy the return and it makes sense (i.e. not wasted).
11) I don't want to have to run the generator except for rare exceptions (using power tools, a really odd run of cloudy days, etc.)

I guess I'll stop for now and see what direction you want to take the thread in. Then I may post more.

Oh, but to answer one of your questions: I don't know of any practical (realistic) setup that would allow you to run an air-conditioner while off the grid unless your generator is running. You will be able to run your microwave (for reasonable periods of time) if you have a big/good setup (I have friends who do, with plenty of solar, a large inverter/charger, and a good battery bank).
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Manitou
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Re: New charger or go inverter?

Post by Manitou »

I was afraid of that for the A/C part. I frequent Florida and A/C is a requirement. I don't want to have to be plugged in all the time and the generator is just so damn loud. I've read that only little can be done to quiet down the existing onan. I've read some (ingenious) folks have changed it out for a honda inverter based unit. I don't know that a single 2k Honda is enough to run our a/c units though? Even with a "hard start capacitor"?
If that is possible, that's the direction I'll go along with an upgrade to the current charger. That upgrade has been covered many places already.
such as:
http://www.tosimplify.net/2012/01/new-c ... erter.html
Manitou
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Re: New charger or go inverter?

Post by Manitou »

funds are starting to recoup from the initial purchase of chinookie..
I still question why I couldn't use a unit like this (and at this much better than advertised price) for a "whole house" inverter:
http://www.imarineusa.com/magnumenergymsh3012m.aspx
Magnum Energy MSH3012M 3000 Watt 12V 125A Inverter/Charger with 120VAC Output

I did read somewhere that you should have at least 400Amps of battery. I can see getting 300 with 3 AGM 31's. Mounting of a 4th would get "interesting".
Still have to account for where to mount the actual inverter too. Under the couch seems to be a popular spot, but I'd rather have it farther away from where I'm sleeping (noise, cancer from who knows what, etc...). The outside storage next to the battery spot maybe. It might not be as clean as the inverter wants though.
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Blue~Go
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Re: New charger or go inverter?

Post by Blue~Go »

I couldn't get the inverter link to load (probably an issue on my end as I have a slow connection at the moment), but what I carry is just a small "plug in and use it" inverter. This works for me because I mostly lead a 12-volt life, with a few exceptions (drill battery charger, toothbrush charger, etc.).
Manitou wrote: I did read somewhere that you should have at least 400Amps of battery. I can see getting 300 with 3 AGM 31's. Mounting of a 4th would get "interesting".
Do you mean in relation to the inverter (?) (Ignore the following if the recommendation was specifically in relation to the inverter since I can't even see which one you are talking about, and am not a large inverter expert.)

Otherwise, in general, I don't see where someone would come up with the "should have at least 400 amps of battery." Reason I say that is that everyone's use pattern is different, and many RV-ers have absolutely no need for 400 amps in their batteries. For them it would be extra expense, space, and weight for no reason. It's a matter of deciding how you want to RV, and then designing a system to support that style.

I love to boondock, and I very well may change to a 12-volt refrigerator (compressor type), so I'm planning a "healthy' sized solar/battery system, and will make use of it constantly. But many (most?) people I know would really have no need for it. On the other hand, those same people would really miss the microwave and AC that I removed (which I don't miss), so it's all about how you use your rig. There is really no one size fits all.

By the way, I have 375 amp hours of batteries under the couch, and had no trouble making them fit (had to trim the cleat holding down the water tank slightly). These same batteries would also fit in the battery compartment if I removed the slide-out tray. Since I went with AGM's I decided that outside storage space was more important to me than "bend down and reach under couch" space, so I put the batteries under the couch. I have three Lifeline Group 31 (model GPL-31XT) at 125 amp hours apiece. Right now they are not hooked up -- I'm still using the flooded cell Group 27 that came with the rig and is in the battery compartment while I plan out and install the rest of the system.
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