Any recommendations on a 12v --> 120v Power Inverter ?

[nusslejj]

I'd like to power up one 120v plug while on the road for a Keurig. Does anyone have a recommendation ? The inverter will need to provide a minimum of 1500 watts. I know I could start the generator, but I'll be driving, and it would be easier/simpler to just have a plug powered up.

Thanks !

[Bluepill]

To drive an inverter that large you will need about 180 AMPS of 12 volt power. How many and what size batteries do you have?

[nusslejj]

I have (2) AGM Size 34M batteries. I will only be applying the 1500 watt load while driving. I think the Sprinter has a 220amp alternator.

[bclemens]

Are those aftermarket added batteries?

I was going to go to an 1800 watt inverter for this reason, by we use a Magnum 1000 watt pure sine wave. My electrical engineer asked to test it before we changed, because he didn't think the 1800 we were looking at had the same surge protection as the 1000w.

On our 1000W we tested a Keurig (not sure which model however), a regular coffee maker with heated plate and the a residential style hair dryer. It worked fine on low...when he went to high, it lasted for a few seconds and cut out. Put it back on low and it fired right back up.

Magnum CSW1012. I think they make an 1800 watt as well. We run (2) Group 31 AGM's and never had an issue.

[Rich.M]

Just put your generator on to make coffee , at lot less complicated than wiring an inverter and carrying the extra weight. Get a coffee joe for dry camp when craving Keurig before generator hours.

[ScottBrownstein]

I have a Xantrex ProWatt 2000 and a 1000 as well. Both seem to work well. Used their remote switches as well as their automatic transfer switches.

[dmdomokos]

We use a 1500w modified sine wave inverter for our Keurig. Run it off of 2 - 6v batteries. No issues, makes many cups of coffee.

[Still Kickin]

If your not going to run the genny down the road, you need to buy an inverter that has enough wattage output. Then you need to determine how your duplex outlets are broken up in your MB unit, by flipping breakers to determine what is what. Then follow the wiring diagram and energize that circuit. It is important to determine what draws are on what circuits. You can't assume, so map out the RV's electrical layout. FR might shoot you a wiring diagram if yiu ask politely.

[camaraderie]

I don't think this is going to work out for you. You have 2... 50 amp hour batts. for 100 amp hours total. Maximum outflow current is about 25% for a wet cell battery or in your case 25 amps..and AGM's can deliver about twice that or 50 DC amps of current without overheating...even with NO losses in wiring & conversion...that is about 600 watts. Way less than you need to brew. Run the genny!

[Tom48]

Originally Posted by camaraderie

I don't think this is going to work out for you. You have 2... 50 amp hour batts. for 100 amp hours total. Maximum outflow current is about 25% for a wet cell battery or in your case 25 amps..and AGM's can deliver about twice that or 50 DC amps of current without overheating...even with NO losses in wiring & conversion...that is about 600 watts. Way less than you need to brew. Run the genny!

I won't go so far as to say that it's not going to work out but it does put a very high amperage load up on your batteries whenever you activate something with a heating element in it. In the old tt we had 3 group24 batteries. In perfect conditions that man 210 amps and since we never want to draw the batteries down more than 50% I had 105 amps available. We ran a Samlex brand light-duty 2000 watt pure sine wave inverter. It was used for five or six minutes of running the hair dryer(maybe 20) and occasionally cooked a TV dinner in the 1100 watt microwave. Mostly we ran everything in the coach except the converter charger so that we could use all of the outlets in the house to plug in cell phones laptops cameras Etc. We had 200 watts of solar on the roof keeping those batteries charged and sometimes that inverter pull the batteries down so much that I was afraid to turn on my Direct TV late at night for fear of pulling the batteries down too far comma after my wife get one of those 20 minute hair drying things

I don't know what those little instant coffee makers use but I'm assuming it's 12 or 1500 watts and for how many minutes I don't know. I would say if it's going to put a thousand or more watts load on the system for more than 10 minutes to brew a quick cup of coffee you're better off getting a percolator

That's just my opinion and that's the opinion of a fairly conservative guy who takes good care of his mechanical things I know that others draw other batteries down until the inverter shuts off and they do infinite damage to their batteries. Your battery is your choice.

I'm not familiar with the Mercedes Benz charging system but I know with a towed vehicle, the towing vehicle does not put very much charge into the RV batteries and and would never replace the charge that a high amperage inverter takes out in 10 or 20 minutes.

I think you are smart to wire just one outlet and that makes your inverter usage much easier to control. Just try to remember that 1200 watts 120 volts is 10 amps amp 120 volt current usage. That will be more like 110 220 amp draw on your batteries. That means heavy cables to the inverter. Short run from the batteries to the inverter. So try it and in the worst-case scenario plan on destroying your batteries before you learn the limits. Good luck and remember you can get a nice stainless steel percolator online for about $45

[camaraderie]

@ Tom... pls. note that my comments were NOT that he did not have enough amp hours in the batteries to make coffee. It was that the nature of batteries is that they cannot deliver more than 25% of their amp hours as AMPS if wet cells...and maybe 50% of their amp hours as AGM AMPS (CURRENT).

It is the SAME reason that a 100 amp charger can't charge a 100 amp wetcell battery any faster than a 25 amp charger can. INFLOW and OUTFLOW amp capability...not amp hours. Sorry if I was unclear about that.

"Maximum amperage that batteries can accept during the Bulk Phase of the charging cycle vary depending on battery chemistry: flooded batteries can accept a charge rate of up to 25 percent of Capacity; gel batteries have a higher acceptance rate of as much as 30 percent; AGM batteries accept the highest charging amps, as much as 40 percent of C."
Selecting a Battery Charger | West Marine

[KatanaPilot]

Originally Posted by nusslejj

I'd like to power up one 120v plug while on the road for a Keurig. Does anyone have a recommendation ? The inverter will need to provide a minimum of 1500 watts. I know I could start the generator, but I'll be driving, and it would be easier/simpler to just have a plug powered up.

Thanks !

Like you, I replaced the flooded batteries with Group 31 AGM's. We use a Keurig also and an inverter would be nice on occasion when you can't or don't want to run the generator.

Although I don't need any more projects on the MBS (and every time you improve yours it makes a new project for me ), we decided not to go with the LTV Unity right now - as nice as they are and as well built - we don't use our MH often enough to justify the investment in an asset that sits in the hangar most of the year. So we are going to improve the Forester with many of the features of the Unity (Alcoa wheels, inverter, TPMS, etc.) and see how it goes. I can spend a lot on repairs and improvements and still be financially ahead. Someone will get a pretty nice Forester in a couple of years though...

[tnjmich]

I am in the same stage as the original poster, planning to install a 2000 watt inverter. I have a new 2401S and am about to add 200-300 watts of solar panels as well.
A question for those that have already installed an inverter is where/how did you do it? I know it should be close to the batteries, so I am planning on putting it under the sink next to the batteries. The real question is did you need switch gear and backfeed the entire coach, or just use the plugs on the inverter? I would really like to understand how to best get the 110v power into the coach/receptacles.
Any feedback or photos would really be appreciated.

[Rich.M]

There are several technical barriers to adding an inverter to the mbs coach. I considered it when adding our solar panels but decided so much of he coach can already run on 12v that it was not needed or not worth the effort for us. The only things we needed 120v to use were the keurig, hair dryer and curling iron ( for Dw), and microwave. AC is a lost cause, you would need a trailer to hold 12-20 group 31 bats and store your 3000-4000 watts of panels. From an individual item standpoint each is doable but for a daily routine boondocking there is not enough battery capacity. Mbs sprinters only have room for 2 100ah bats. You could add batts to another compartment but Sprinter is already at load limit on wt. Class A coaches running on inverter use banks of 4-6 bats and you would need to replace all the amp hrs for these high demand items. On the solar side you might need to be at 600 watts . That won't fit on sprinter and again adds wt.
On the power use side 1000 watts 120 volt for 10 min to make 2-3 cups of coffee will draw about 80-90 amps brewing and 15 amp hours or more. Add 10 min of hair dryer and microwave and you just used 45 -60 amp hours. ( remember amp hour rating is at 10 to 20 amp per hr and not inverter load) You likely will have taken your 2 batteries below 50 % and you have not allowed for fridge 12v use , lights , detectors, pump ,using tv or fans. They will be roughly 30 to 50 amp hrs over 24 hr. Also repeated heavy draws or heavy draw the next morning when bats depleted will drop voltage, most inverters will shut down if voltage falls below 11.5 to 10.5 v depending on brand. Choose carefully.
Wiring 1 or 2 dedicated outlets are fairly straight forward if you still want the inverter, run as short of 2 ga wire to inverter then run std 120v wiring to the outlets.
Powering the existing outlets requires a detailed electrical knowledge and or an electrician. You can't just back feed since the converter needs to be cut off by another added transfer switch or must always manually shut off. Also the fridge will try to switch to ac when it sees power . You might need to set up a secondary panel to limit what circuits get the inverter Ac volts . Very complicated.
Inverter makes sense for low amp 120 needs like computers etc on a dedicated outlet. Your coach is equipped with a national park compliant genny on an automatic transfer switch that can be turned on with the touch of 2 buttons in the kitchen even when driving. Generator hours at parks always include dinner time and morning even it you just put it on for 10 to 20 min. In the end we decided to just use the generator when we need it. We do use a Myjoe to press boiling water thru kcups if early am . Added 12v USB ports throughout coach to charge devices and a 12 volt cell booster and 12 volt Wifi ranger. Our solar panels can replace 100 amp hours per day. I don't feel like We are missing out on anything.

[tnjmich]

Thanks for the reply Rich. I will likely just get a small inverter for portable electronics charging, maybe a 500 watt. We do a lot of dry camping and are good with LP and 12v for everything else. I want to add the solar to keep the two batteries charged. According to Renogy, 200 watts is ok, but 300 watts would be better. We all have different power needs, but I want to stay with the 2 house batteries. How many panels do you have and how many would you recommend to keep the 2 batteries charged?

[Rich.M]

We have 400 watts of the renogy eclipse panels and a samlex 30 amp PWM charger. We harvest 100 to 115 amp hrs on sunny days less with clouds. We are admittedly 12 volt power hogs needing to charge 3 iPhones and 3 iPads daily . Three people to get thru showers on pump , 32 inch tv in the evening and cell booster. We leave the fantastic fan on when out to keep the coach cool dry camping . Probably could get away with 300 watt. 200 watt probably would not be enough to if to many clouds and you are using inverter for electronics. Consider 12 volt wired USB ports if your devices can use them. No inverter loss. I installed 4 dual Blue sea USB adapters around the coach and highly recommend them. Can be another string topic if enough interest

[ScottBrownstein]

OK...so the OP really likes his coffee and there is no reason that he can't have it in a MBS as long as the engine is running. All of us with residential reefers do the same. He can do it this way:

1. A 2000 watt inverter like a Xantrex ProWatt will draw a lot of power when running, like more than 150 amps at full power, and the MBS dual battery setup will only be able to supply that full load for 45 minutes or so. I do wince about running a hair dryer off of a couple of poor 12 volt batteries, but it can be done. My assumption it that for more than say 500 or 750 watts, the engine and alternator will be running and supplementing the battery power.

2. The reason that I recommend the Xantrex (besides the fact that I have two of them) is that if you install their remote on/off switch, it has a line that goes to the ignition switch which will automatically prevent the inverter from running when the engine is off. (there is a switch to defeat this however.)

3. A Xantrex automatic transfer switch (nice little box) is installed between the inverter and the outlet circuit that it feeds. This will automatically switch to shore power, dropping the inverter when 120 volts is available automatically. The closer to the breaker feed that this is installed will enable as many outlets for "automatic" AC power as possible.

4. Very heavy gauge wire from the batteries to the inverter and as short as possible. In the MBS under the sink would be really close and installing the remote on/off switch on the bulkhead by the stairs would be easily reached. The transfer switch goes inside the same cabinet and intercepts the feed from the breaker to the outlets that are powered.

In short, this ain't rocket science. I love having all of the outlets in my coach (with the exception of the kitchen outlets) always powered when running down the road, and love to watch TV without resorting to firing up a 5000 watt generator!

The inverter:



The remote on/off switch:


The automatic transfer switch:

[Rich.M]

Tv 's in the MBS coaches run on the 12 volt .

[camaraderie]

Scott...good post...but the OP is using GROUP 34 batteries...50 amp hours each. Even with your solution...they can't deliver that current without doing damage. A battery up grade + your solution will make this the worlds most expensive Keurig....until someone comes along and upgrades their Keurig to lithium ion! LOL

[ScottBrownstein]

Actually...it will work with group 34s as well. Lots of trucks use inverters tied to the alternator, hence the 12 volt lockout.