Choosing An Inverter/Charger
If you're new here, you may want to subscribe to our E-mail Digest. We will then send you the stories that are posted each day in an e-mail digest. We use a service called Feedburner for delivery of these emails. You will receive an e-mail from Feedburner after you subscribe and you must click on that email to activate your subscription. Thanks for visiting and enjoy all the information!
RV.Net Blog Admin
So far as motorized recreational vehicles, there are two duty types of inverters used. Stand alone and integrated inverter/chargers. Stand alone units are relatively low wattage output units that are individually wired to operate a single load like a television and perhaps a satellite receiver. The inverter/charger is an integrated part of the electrical and charging system of the unit. The inverter in this case serves two purposes. First it is the main battery charger, at least while either an outside source or generator is supplying AC power. Secondly, it is an inverter that supplies AC power when none is available. Once AC power is absent, the inverter automatically takes over, providing it is in the armed mode state. It is normally wired to operate necessary functions within reasonable wattage like T.V’s, receivers, duplex outlets, refrigerators (if an all electric coach), ice makers and perhaps microwaves.
There are two output configurations available, M.S.W. (Modified Sine Wave) and T.S.W. (True Sine Wave). All smaller or cheaper inverters are M.S.W. Most motor home inverters are also currently M.S.W. The exception of this would be higher end units and newer all electric coaches, most of which are equipped with T.S.W. output inverters. So what are the operational differences?
M.S.W. gets it name from exactly what it sounds like. It is a modified look-a-like wave. However it is more “square” than the smooth sweeping frequency lines that are created with a true sine wave. These inverters are cheaper to buy but function well in most applications. There are however, loads it does not work with or properly with. Those loads are, but are not limited to, many small power chargers, electronic boards found in many appliances, most microwaves, 120 volt A.C. powered clocks and full featured cappuccino makers. Some of these will not operate and some may be damaged over time with continued use.
T.S.W. power resembles that of home supplied hydro. It is capable of operating any like voltage load providing it does not exceed its output capacity. These units are now to a price level making them the best choice for future use.
So, if you are ordering a new coach, or replacing or upgrading to an inverter charger, should this be a “must have”? In my opinion, it is. The benefits far out weigh the now small price difference. If you own a coach that has a M.S.W. inverter charger, like most do, don’t worry. Your coach was equipped to exist with such a wave form and should do fine. But, just remember, if you were to order a new rig or ever it has to be replaced, go T.S.W. You won’t regret it.
On Sunday the 13th of july, we will be looking at “Practical RV Inverter Applications”. I sure hope you can join us.
Just Reading The Sines - Lug_Nut - Peter Mercer
Last 5 posts by Lug_Nut
- Not All Tag Axles Are Built The Same - November 16th, 2008
- Justifying A Tag Axle On Your Next Coach! - November 9th, 2008
- Ways To Reduce Fuel Costs: Another View #2 - November 2nd, 2008
- Ways To Reduce Fuel Costs: One Method #1 - November 2nd, 2008
- Is Synthetic Engine Oil Worth The Buck$? - October 26th, 2008
I have a question for you, is it Ok to run your generater while running down the road, this way I can run the air in the RV instead of useing the air off of the motor?.
Thank you.
There is no reason that you can not run your genset while driving. Many do this for that exact reason, to run the air conditioning. On a hot day I normally start mine about an hour prior to stopping for the night. That way it is nice and cool immediately upon arrival.
Xantrex says: “With filtered modified sine wave output, Freedom inverter/chargers run virtually anything, from electrical equipment to appliances and electronics in your RV.”
I have two 3000 watt Xantrex inverter chargers and lots of electronics, chargers, microwave, computers, electronic appliance boards, fancy coffee/cappuccino maker etc. I have never found anything that did not run properly with these filtered, MSW inverters so I believe the comment above about “many” items requiring pure sine wave are a bit misleading. While there are some items that may not work I have not found one yet.
I would think you have been very lucky. I’ve experienced several issues over the years with several items. Additionally it is common knowledge that MSW power runs many products at higher temperatures than that provided by a pure sine wave inverter.
I was looking for an interest in fuel savings blog that might be on your site and I ran across the inverter/converter article which is a very informative blog . I noticed that the voltage scale on the shown AC sine wave =< 480 v (*240 -240) which is a little strange for the 120/240 vac output. Is it really that hi of voltage? I enjoy reading the issues that you have posted.
Dennis, The charts shown are actually a 240 VAC output with 24 VDC input, but they were really just to illustrate the difference in wave profiles.
You mentioned fuel savings, my article this coming Sunday is in fact on that topic. Hope you can catch it.
Hello again Lug_nut,
Once again you have captured my interest with another informative article.
Keep them coming!
I recently purchased a Go Power GP-SW600 Inverter at dealer cost.
It is my understanding that this unit produces :Pure Sine Wave” power
which is best for more refined electronic applications such as televisions, computers etc.
I will be installing the unit next week and was wondering if T.S.W. is the same as “Pure Sine Wave” power. The unit is only 600 watt output, enough for our tv and coffee maker/grinder and will suffice until we get our new “A” class next year.
Also, from your personal experience, is there a preffered brand or feature you can suggest for our future “A” class diesel pusher?
Cheers,
John
Hi John, TSW and PSW are the same, they are both true sine waveforms. I should have made that point also within my blog. There are several good makers of both MSW and TSW inverters Currently I have a Magnum TSW in my coach. It is cpapable of five stages of charging which includes equalize. Since I have AGM batteries, equalize is not needed as it should never be used on this type of battery type.
I think you will find pretty well all the makes that offer TSW and four or five stage charging will deliver good service. Therefore it is probably more important to select the right DC output that you require and the correct charger output for the capacity of your existing battery bank. Best of luck.
Is it possible to run one 15Kbtu a/c on an inverter battery bank?
Roseport, Yes, running a 13.5 k or a 15 k roof A/C unit on an inverter is certainly possible and has been offered in a couple of higher end coaches in past years. It would, however only really be usable while the engine is operating due to the high power draw which would probably be in the 180 amp/hr @ 12 volt range. This then would also require a substantially large engine altenator output capacity of 250 amp/hrs or higher. The inverter would have to be 4000 watts or higher to handle the compressor start up loads, or perhaps even a pair of 3000 watt units. A large battery bank would be needed to act as a buffer during the high load demands that may exceed the available altenator output current.
Keep in mind, this would probably not be any more fuel efficient than that of running your generator as a high capacity altenator under load takes a substantial amount of horse power to operate.
i have a xantrex powerx 1750 power inverter. when i put dc. power on my unit it shows the right voltage in, but can’t get any ac. power out, the fault light come on.
is there a fuse or something to do to reset the unit. i have only used this unit 1 time sence i bought new3 years ago.is there a phone to tech support that you would share.
777) 489 0814
d roberts, The Xantrex 1750 does have a fuse which typically protects it against reverse polarity on the input side. Perhaps you could check that first. Xantrex’s support phone number for that product is recorded as 408 987-6030. I hope you get it figured out.
If you install an inverter/charger does this replace the converter/charger or will you still need the converter to supply 12V DC when hooked to shore power or genset?
Cruise350, The inverter charger replaces the converter charger as looks after the charging, 12 volt supply and inverts 12 volt dc to 120 ac.
On the 13th of July, Sunday, I have a blog that features practical RV inverter applications. Hopefully you can catch it as it may help you to understand more about these great options.
thanks for the info on inverters….quite topical for me considering i just installed a 1500 watt unit in my MH. It is a separate unit connected directly to my 2 12 volt parallel batteries. However, when i checked the voltage output it measured 96.5 volts rather than my expected 120 volt range. Do you have any suggestions on getting a higher output or might i have to be satisfied with the lower figure? Any help would be appreciated.
Hi Tom, No, 96.5 volts AC is not acceptable. You may need to do some tests first, to determine the problem prior to contacting the manufacturer.
First, take a voltage reading at the DC input while it is producing the 96 volts. If it drops greatly you may have a poor power source. Also, if it is possible, get an amp output on the AC side to check you are not exceeding the output capacity of the inverter. If all this checks out, contact the manufacturer of the unit. They will probably ask about the input voltage and output loads, so you will be prepared. But, definately, it is not acceptable at the current output level. Best of luck.
Hi,
I have a ‘93 VW Eurovan Camper. The inverter charger bit the dust & I’m wondering if I can substitute yours for it.
Tks,
\J
Jaye, I’m sure you could find a like size from a choice of several manufacturers, including a true sine wave, if you so wish.
Great article Lug-Nut! I always enjoy your posts. It inspired me to write an article of my own. Check it out here:
http://www.modmyrv.com/2008/06/14/mod-10-power-inverter/
I have a problem with my Inverter/Charger. I have a sprinter tralier and it seem the the charger for the battery is not working . what is the best way to repair this ?
2002 tralier
Stan, You can check that the fuse between the charger and the batteries is not the problem. If that is okay then probably the best thing is to remove it and take, or send it, to a suitable service center. Without knowing the size or type, you may find it cheaper to replace with a new one as apposed to repairing it.