So confused!!

[tucsoncarol]

Alright, I think some of my confusion about replacing the converter began with my inability to distinguish converter/inverter. In the many threads I've read you have replaced converters with BETTER converters not inverters (yes?).

Here is the situation I'm in. My hubby has a CPAP machine now, and I know some of the rest of you use them. I'm suitably terrified of a loss of power while boondocking that I need either solar panels or a generator. In comparing pros and cons the list is almost endless, but a serious consideration is cost. I've located an on-line source for a Honda Eu2000i at $860.99 delivered (if I haven't missed the sale. Otherwise it's Camping World at $999) and Costco on-line sells a 160 watt solar package for $899.99 plus s&h and tax. Weight is in the same range, and the prices are close. When I look at the overall situation, I just can't decide. I'm thinking that very long term the solar panels will be better, but I'd like to hear more opinions if you'd care to share.

I elected to use a EU2000 for my 110 electrical needs during the day, as well as charging the two 6v deep cell batteries. At night I run my BIPAP off the batteries using an inverter. However, my BIPAP requires pure sine wave power, so you can not use just any inverter. Depending on your requirements for the CPAP, if you have a humidifier, will determine how big an inverter you will need. Some CPAPS have a 12v adapter that will run them directly. Check with your provider. If you do need a pure sine wave inverter, take a look at this site.

http://www.voltageconverters.com/cus...PS100012V-4AWG

They have different sizes.

[Bill]

Carole -

Let me toss in a couple things. You asked

If I install an inverter with a battery charger do I remove the converter?

OK, good, we're talking about three separate hunks of hardware - inverter, converter, and battery charger. So let's talk about them individually.

As was noted above, the purpose of as CONVERTer is to CONVERT shore power (120 VAC) to 12 volt DC power. This DC power will run your DC loads, such as the ones noted. Shaver, computer, furnace blower, etc.

Since a CONVERTER produces 12 volt DC power, and since 12 volts (and a little circuitry) is what is needed to charge a battery, it is easy for the manufacturer to add a BATTERY CHARGER to the same box. He doesn't have to do so, and you can buy a converter without a battery charger if you want to. But building in a battery charger is commonly done. A semantics problem arises because the dual-function box is still called a CONVERTER. To be fully descriptive, it should be called a CONVERTER + BATTERY CHARGER. But it isn't.

OK, I hope that the above lays out the functions of the converter and the battery charger. Note that we haven't mentioned the inverter yet. It has nothing to do with anything we have talked about.

As was noted above, the inverter does the opposite of the converter. If you are in a situation where shore power is not available, but you still want to operate some of your 120 VAC appliances, then an INVERTER will take battery power (12 Volts DC) and make it into 120 VAC. Now you can run your AC appliances. This works quite well for small appliances that don't consume much power (TV, computer, cordless drill, table lamp, etc). But for various reasons which aren't really relevant here, it is quite hard on your battery if the load is large (toaster, microwave, etc), and virtually impossible for really large loads (air conditioner). That is why small RVs like TMs seldom have an inverter - and if you add an inverter it will be a small one.

In the first paragraph, I said that a CONVERTER doesn't necessarily contain a battery charger, but if it does, there is a semantic problem because often, the combination is still called a converter. Guess what? The same semantic situation arises with an INVERTER. There is nothing about an inverter that needs a battery charger, and most inverters don't have one - but occasionally you find one that does. And it is still called an INVERTER.

If you have shore power, you will connect it to your CONVERTER (and battery charger if it contains one). Since shore power will run all your AC appliances, the INVERTER has no function, so it is switched out of the electrical system, usually automatically. By the same token, if you don't have shore power, then your CONVERTER has no function, so it is removed from the circuit. The inverter will make AC power if you need it. You never need both at the same time.

Now we still haven't talked about solar. Recall that a converter CONVERTS shore power (120VAC) to 12 VDC, which can be used to power the DC loads. Solar does almost the same thing - it converts sunlight to 12 VDC, which can be used to power loads. In both cases, some of the 12 VDC power can be used to charge your battery. If you are using a converter, you need a battery charger (which is probably built in). If you use solar, you need a Charge Controller. As far as I know, there is no reason why you can't have both, running at the same time. Don't discard anything.

Hope this helps. Sorry it got so long - I thought it would be simpler when I started. Just remember that all of these units are functionally independent of each other, even though they may be packaged together.

Bill

[Bill]

I just reviewed my previous post, and it seemed kind of confusing (pompous, my Dad would have told me). So I'll retreat.

Carole, it seems to me that you are asking about a practical problem - how to ensure that the TM battery is charged up enough to run the CPAP machine all night, every night, without fail. Does that describe it well?

There have been two good threads on how to power CPAP machines. I'm sure you have reviewed them, at

http://www.trailmanorowners.com/foru...ead.php?t=3580
and
http://www.trailmanorowners.com/foru...ead.php?t=1709

As I recall, a CPAP machine draws enough current to drain a battery in one night, more or less. You can get through one night, but you won't get through two nights. So to start with, I think you should forget converters, inverters, solar, etc, and ask the basic question "how am I going to charge my batteries every day, in preparation for the coming night's use?"

There are three answers.
1. Shore power. No problem. If you've got shore power, the converter that came with the TM will charge the battery without fail.
2. Generator. No problem. You will have to run the generator for a while every day, but it will charge the TM battery without fail. In fact, by plugging the TM's shore power cord into the generator, you have the equivalent of shore power. You don't need a very big generator, by the way, if this is the only use for it.
3. Solar power. As Texas Camper pointed out, this can be a problem if you have a cloudy day, or if you park your TM in the shade. If your real requirement is MUST CHARGE EVERY DAY WITHOUT FAIL, then solar may not be right for you, just because there are some days when it won't charge.

If shore power is available, then there is no problem - the CPAP runs from shore power. If shore power is not available, then the remaining question is how to power the CPAP from battery. The answer seems to be that there are two alternatives.
a) Some CPAP machines can be powered directly from 12-volt DC power. You plug it into a cigarette lighter outlet, and it runs. Easy.
b) Some CPAP machines can be powered only from 120 VAC power. This is where the INVERTER comes in. The inverter will take DC power from the battery, and make AC power for you. It is a bit more complicated, and it wastes about 15% of the power it takes from the battery, but it will work fine. And I think the AC-only CPAP machines are probably less expensive. The threads noted above discussed this question.

Now, the above is a little simplified, but not much. There are some details about how big your battery should be, and what is the right charge rate, and what happens if the battery is insufficiently charged (is there an audible alarm on the CPAP machine, to wake you up)? These are also covered in the threads listed above.

I'm sure this doesn't answer all questions, but let's start from there. What are the next questions?

Bill

[tucsoncarol]

Well, Bill, now you’ve done it. I thought I was confused before, now I KNOW I am.

Let’s just jump right in, shall we. Looks like you’re in Arizona, too, so you know that nobody gets more sunlight than we do. That being said, I try to avoid sunny camping spots. Looks like solar is not really an option. I think I wanted that with my heart but knew I needed a generator with my head. Since neither part of me is at issue here, let’s move on.

My hubby uses a Respironics RemStar Plus CPAP unit that we did buy a 12v adapter for. We thought that would make things easier (silly us). A Honda EU2000i generator looks like the way to go. Anything more is way too heavy and anything less won’t cut it power wise. Also, if one EU2000i isn’t making it, we can still get a second to hook up without much trouble. Now the weakest link seems to be my battery. It’s what came with the TM. Looking at the previous posts points me toward two 6v batteries as being a better bet. Am I right so far?

Next we can address BobRederick’s battery meter. That also seems prudent although my now mushy brain is having trouble remembering why….Oh, yeah, so we’ll know how our batteries are doing charge wise. How will that work with the two battery setup? Is that going to be a do it myself deal, or a professional install? If I’m still running the right direction that only leaves a CONverter upgrade. I have to say I have no idea what is in my unit. I have a 2005 TM and I know they have changed manufacturers several times. I will have to physically go look at it as I have no documentation for it in my owner’s manual. I know there are several threads about the various models and manufacturers but as I recall none of the factory installed units is all that good and therefore a change out is in order. Is BobRederick’s choice a good one for the situation I have lined out?

Finally (?) what have I forgotten?

Thank you all for the time and patience you’ve shown. I love this forum!!

[Bill]

Carole -

Somewhere on the CPAP machine, it should tell you how much power it uses. It will be stated as either so-many-amps at 120 VAC, or so-many-watts at 120 VAC. What does it say?

An EU2000i is way overkill if battery charging for the CPAP is all you want to use it for. Even an EU1000i is overkill. However, being in AZ, you probably want to use the air conditioner once in a while, and the EU2000i may be just barely adeqaute for that (members of this board have reported mixed results).

The battery that came with the TM is probably not adequate. It is most likely either a Group 24 or Group 27 "Marine / Deep Cycle" battery from Interstate Battery - as I recall, these are called SR-24 and SR-27. An upgrade to at least a pair of these - or better, a pair of 6-volt Trojan golf cart batteries - would be a really good idea.

The battery charger that came in the TM's CONverter should be adequate - but it may not be. After TM phased out the old Parallax/Magnetek 6300-series converter, all of the new ones have had sufficient charge capability to bring as battery up quite quickly. Problem is, they tend to cut off charging too early, in an effort to avoid overcharging. As a result, it takes hours to top off a battery, which is not what you want when your source of power is a generator. There are several "good" chargers that don't do this, but it appears to me that Bob's PD-6100 or -9600 (I think there are a series of them) is the best bet for reasonable cost and reasonable capacity. I'll let Bob tell you the details.

Finally, Bob's Xantrex Link-10 Battery Meter is a thing of beauty, and I covet one terribly. But they are expensive, and in all honesty, I'm not sure you actually need one. I'll let Bob tell you not only what it does, but why you need it. By the way, Bob is in AZ, too, so he might show you his setup if you get up Phoenix way.

Bearing in mind that I have ZERO experience with CPAP machines, I think that if I were you I would have two things.
1. A low-voltage alarm that will wake you up if the battery voltage drops low enough to make the CPAP machine struggle, and
2. A spare battery, fully charged, in the trunk of your car. Perhaps this could be the battery you take out of your TM if you put in golf cart batteries.

Bill

Carol:
With the Honda EU2000 units, you can use a direct 12v charge cable, that will bring the batteries up in a much shorter time. Use the 110v ac for your normal appliances, but have a direct charge cable for your batteries. I have two 2000 units, because I owned one for my previous camper, (the A/C did not require as much power). The TM A/C needs more power. Also I can pick up the 2000, but I couldn't pick up the 3000. Bill is exactly right about the batteries either have a spare 12v battery, or have the 6v deep cell set up.

[Bill]

Rob and Clare -

I should have been clearer - and I certainly don't mean to be disagreeable. But the specs for both the Honda EU-1000i and the EU-2000i show a max battery charge rate of only 8 amps from the direct charge cable. That just isn't very much. And I have been told that charging tapers off early, just as it does in many simple battery chargers. This means that the generator won't give you even the meager 8 amp charge rate unless your battery is deeply discharged - something that should not be allowed to happen.

Bill

Carol,
So it seems that from Rob's post you can get away without upgrading your converter for quick battery recovery. This is probably a good thing because the upgrades are not all that trivial and while Magnetek to PD-91xx series conversions have been done, I have not heard of the later TM converters being upgraded, so you would be a first, possibly. Your dealer might tackle it, but I'm sure it would be expensive.

Your CPAP machine is rated at 3A max @12V and 1A max @120V. While these figures are undoubtedly rounded up, you should still use it at 12V since this is more efficient. Hopefully, a companion heated respirator is not used since the user manual states this is AC only and cannot be run from inverters (I suspect however, that a pure sine wave inverter would be OK, though).

A battery upgrade is worth it, at least an upgrade to a second 12V battery. The dual 6V battery upgrade is the best , especially if you want to boondock a lot.

Bill had a good suggestion with the spare emergency battery in the car. You might look at those $50-60 automotive jump-start sealed units. They go up to about 19 or 20 amphours and so should be OK for several hours, maybe a whole night, of emergency CPAP power. They have a connector usually that will directly fit the CPAP DC cord, you won't have to worry about electrolyte spillage, and you can use it to start car or pump a tire up if you want.

Low voltage battery alarm: I found these on the web. Much cheaper than a Xantrex:
http://www.batterycellmate.com/bat_alarm.html
...or if you're handy with a soldering iron and want to make a project of it:
http://store.qkits.com/moreinfo.cfm/FK915

When the time comes we can go into what voltage to set these up at (e.g. for 50% discharge to prevent TM battery damage versus 'CPAP about to fail" voltage). Hmm.... maybe two of these would be useful.

-Paul

Carol,

I am sorry, I didn't know you were powering a CPAP. However, that does make your and my (former) issues the same. We don't want to run out of battery power at night.

The best thing I can suggest for that is the battery meter. You can get a rough idea of remaining capacity by looking at battery voltage and after using the TM a few times, grow in confidence that this is reliable. However, if you want to look at a meter and say "I have half of my capacity remaining" or I am at 75%" then you have to have a battery meter. It definitely gives a lot of peace and comfort.

It looks at what you have used, how fast you used it and estimates by a mathematical algorithm what is remaining. So it is a very educated guess at remaining capacity. It gives this answer in terms of hours remaining as well as in Amp Hours used. I think you need that. I did and for the same reason. It isn't nice to wake up with this problem in the middle of the night. And it will take the fun out of the outing and out of the outlook for another outing..

Difficulty level: The Xantrex and Trimetric are about alike. I don't remember exactly why I bought the Xantrex, but it is only slightly higher in cost when you consider it includes the shunt while the shunt is extra cost on the Trimetric. The Xantrex is smaller and can be mounted on the panel by the switches for the water pump, etc. Some links are below.

Wiring is pretty minimal on these installations -- meaning technical knowledge required is minimal. They include good pictures and instructions. They can help you on the vendor's web site as well.

The tough part is getting into the areas needed to install the shunt and the meter. Also, where to run the cable from the shunt up to the meter installation location. For the shunt, you need to cut the negative wire going to your battery and simply put the shunt in between the cut ends of
the wires. I placed the shunt on the floor under the tub next to the converter (that's where the converter is on the 3326). Then the shunt needs to be screwed to the floor. Lastly, there are 4 (if I remember correctly) small wires to hook up to screws on the shunt. These wires are best purchased with the shunt in the form of a rubber covered cable that can be run to the location where the meter will be installed. Then the 4 wires in the cable are hooked to the meter screws. That's it. It is not "plug and play".

If I also remember correctly, it looked like the Link 10 will be replaced by a newer model. You don't need all the fancy computer hookups they have optionally. Those are more for folks who are powering a house.

http://houseboatingworld.com/store/S...p?idProduct=52
http://www.bogartengineering.com/
http://www.hondapowerequipment.com/g...EU2000i#EU200i

The folks above helped decide on battery selection. I don't know how much you are using per night. But they gave good advice.

I hope this helps.