Inverter question

Todd77

Hey, I was hoping someone could direct me to some good inverter options.  I am not sure if I want to go through with a full on install project, versus maybe getting a pure sine wave portable inverter.  Any thoughts?

DougH

Just don't ever mix AC power sources, do monitor the battery or batteries, and do fuse inputs and outputs (I've burned some inverters up).  Aside from that, Amazon has plenty of decent sine wave inverters from $200-500 depending how much you're planning to power.

Todd77

Thanks for chiming in!  I have 2 6V batteries and a Zamp 180 Watt portable solar panel.  I imagine when boon docking I will be not be using too much AC power.  The only thing I can imagine wanting to use is outlets to charge laptop, possible toaster oven (not necessary), and possibly an apple TV here and there if I can figure out internet accessibility.  Everything else seems to run on DC and Propane (like Alde heating system?).  I only have one 20 lb propane tank, so I imagine I may want to get an extra tank, at least during the cold months.  The price range you mentioned seems to be for the ones you wire in so you can use the outlets.  Is that right?

DougH

That's handled several ways.  Some folks run a thick pair of wires (one switched and fused) from their two 6V batteries in series to an inverter.  The inverter can be screwed to the inside side of any cabinet. If more than 1000W it will need ventilation since inverters are only 85-95% efficient and have to get rid of the waste heat.

Then some folks just run a short extension cord out from the inverter tucked into a cushion, or just inside a cabinet.  Need AC power boondocking... just plug one or two appliances into that extension cord.  Easy. Cheap.  A few hundred dollars if only running low wattage. Toaster ovens are high wattage. 

Next step up is to run that extension cord or Romex to one or more dedicated new AC plugs.  A little cutting into cabinets, and a few bucks for the AC outlets and extra wiring.  You'll have six plugs for shore power, and maybe four new ones just for inverter boondock power.  Simple, cheap, user friendly. 

Another cheap step up is to do a male-to-male extension cord and plug it into a high allowed current plug like the one next to where the Alde plugs in.  Cheap, but you're entering wormhole territory.  A 1000-2000W inverter can act just like shore power in this way.  The juice flows to the converter and powers everything DC (less efficiently than just powering them from the battery).  The converter has to be prevented from trying to charge the same batteries as are powering the inverter though (highly wasteful loop that will eat the batteries). So there's another switch.  But then the inverter power will power your fridge on AC, all plugs, all DC appliances and USB plugs.  And NEVER EVER EVER plug in shore power if running inverter that way since AC sources cannot be mixed.  Lotso stuff can be burned up.  But cheap solution.  Only one M2M inverter output (fused), and one more switch if converter normally charges inverter battery bank. 

Next step up from there is what you said you don't want to do.  New auto-switch relays.  Lots more wiring.  Possibly new converter made for multiple sources.  More fuses. 

pthomas745

Inside the Tab I use small 300watt inverters plugged into the 12V sockets for the small jobs like laptops and camera batteries, etc.  One like this:  https://www.amazon.com/gp/product/B01N3Q8YAI/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

I read the wall warts or the product labels to make sure any of the things I might want to plug in will work comfortably with the inverter.  The laptop is probably the biggest item at about 45watts.

For bigger things I carry a 900 watt inverter that connects with clips connected directly to the battery.  I've used a couple of 700 watt things for very short periods of time, and it works. 

There have been some threads on inverter installs:

https://tab-rv.vanillacommunity.com/discussion/4182/inverter-install-question

Todd77

Awesome, thanks!

DougH

For the $100-200 lower power pure sine wave inverters that plug in our DC sockets, are there brands that work great and some not so much?  My camera and laptop only like pure sine wave (otherwise there's a unhealthy buzzing sound). 

N7SHG_Ham

@DougH I have found the Samlex inverters work good, pretty expensive compared to some, but nice clean AC and no hash that I can discern. I think with inverters you get what you pay for.

klenger

I am just now finishing the installation of a 150 watt sine wave inverter  in my 320 S.  Everything is permanently mounted and hard wired to all the outlets, including one I added for an Apple TV.  Switching is fully automatic.  A 150 watt inverter will top out at about 15 amps at full load.  I could have gotten a 300 watt inverter for about the same size and price, but I couldn't think of anything I wanted to power that used between 150 and 300 watts. I will use it primarily for charging my Surface Pro laptop and powering the Apple TV.  It will also power a small crock pot that I have that uses about 100 watts.  I also have 200 watts of solar and a 100 AH lithium (BattleBorn) battery, and finally a Bogart battery monitor for watching performance and battery level. Will also have a Honda EU2200i generator as soon as Honda lifts the sales restriction on it.  I'll try to get my drawings posted in the next day of so.  They will be posted on my website at the link in my signature.

klenger

I have updated my wiring diagram to include the AC power distribution (sheet 4).  The inverter details are on two sheets: Sheet 3 for the DC wiring and sheet for for the AC wiring.  Clink on the link in my signature and look for Wiring Diagram on the top menu.

pthomas745

Beautiful diagrams!  What did you use to make them?

klenger

Thanks.  AutoCAD.  Aerospace engineer since 1984. 

Olena

I think I am in the right thread. I am looking for advice to use my sewing machine by solar power. The specs on the machine are: 115V, 60 Hz, 105W, needs a nominal 120V circuit, must be grounded. I currently have a 120W solar panel and my battery is the basic dealer installed one. What is the most simple and cost effective way to use the machine for about three hours per day? I am not technical and would prefer something as plug and play as possible!!!

DougH

N7SHG_Ham said:

@DougH I have found the Samlex inverters work good, pretty expensive compared to some, but nice clean AC and no hash that I can discern. I think with inverters you get what you pay for.

@N7SHG_Ham : No doubt, but my budget sadly doesn't support that level of quality.  Currently using the Giandel 2200W / 12V and it cleanly runs the A/C and espresso machine, but I don't know what the longevity will be. 

https://www.amazon.com/dp/B07CKBJ9KP

Once it dies, I may switch over to a 24V or 48V setup and save 20lbs of wiring.

DougH

Olena said:

I think I am in the right thread. I am looking for advice to use my sewing machine by solar power. The specs on the machine are: 115V, 60 Hz, 105W, needs a nominal 120V circuit, must be grounded. I currently have a 120W solar panel and my battery is the basic dealer installed one. What is the most simple and cost effective way to use the machine for about three hours per day? I am not technical and would prefer something as plug and play as possible!!!

Just a guess, but that's only 1A or 3Ah/day.  You can read the inverter install thread above, but you may be able to use a 12V plug-in 200-400W pure sine wave inverter that goes right into one of your existing lighter sockets like pthomas745 mentioned.  Won't be truly grounded, but the inverter plug will be a three way.  Probably won't even have to upgrade the battery.

[EDIT] 1A in 120V AC, but 10A in 12V DC.  So 30Ah/day is too much depletion from the inexpensive lead acid batteries most dealers stick in the tub.  As stated below, need a larger capacity battery and monitor. 

pthomas745

You would need an inverter to plug into your 12V plug in your trailer.  Since  you know your machine is 105 watts, this 300 watt inverter will work (or one like it).  You really don't need more than a 300 watt inverter.

https://www.amazon.com/gp/product/B01N3Q8YAI/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

The inverter plugs into your 12v plug, and you plug the machine into the inverter.

And, now some math:  105 watts divided by 12 volts equals 8.75 Amps.  Your machine will use 8.75 amps per hour to run from that inverter, drawing the amps from your battery.  I'm going to round that up to 10 amps per hour to make my math easier and because inverters always waste some power in the conversion.

If this was my trailer and battery:  I have the stock battery that came with the trailer, with (about) 70 amp hours.  To preserve the life of my battery, I try to use only 50 percent of those amp hours.  So, I have 35 amp hours to use.

The machine will use 10 amps per hour.  I have 35 amp hours to use.  35 amps divided by 10 amps equals 3.5 hours of use.  In other words, I could plug in the machine to the inverter, hold the pedal down and I can run the sewing machine for 3 1/2 hours before bringing my battery to the 50 percent level.  I know that isn't how you might run a sewing machine, but taken all together your three hours of use a day is do-able.

Major caveats:  10 amps is pushing the limits of the 12V plug.  I just searched for 20 minutes and cannot find the answer on what the amp limit of the 12V plugs are, and what fuse they are wired to.  (The answer is out there.....) Maybe someone else can chime in. 

You need to get "technical" if you want to do this.  How do you monitor your state of charge in your trailer?  What is the exact size of your battery ( the 20 hour amp rating?).  How well do you understand how your solar panel replenishes the battery while you are using it?  None of this is very hard, you just have to pay attention to protect your battery and the fuses in your trailer. 

Olena

I am also looking at the Yeti Goal Zero 400 and a 100W panel. It would be nice to keep the machine separate from the camper so I don't have to worry about using too much battery up (and then not being able to use my fan, water pump, etc.). Has anyone had any experience with these? Sewing is my work and not a hobby, and anything I buy is a business expense, so within reason I just want to find what is reliable. I camp all summer in a campground that offers electrical and non-electrical sites, but the electrical campgrounds are so packed and noisy. Hardly anyone is in the non-electrical area, so moving is not an option!

DougH

@pthomas745 : Oops... I forgot to multiply by 120/12.  Dang that new math anyway. 

DougH

@Olena : So you get to write off the T@B as a business expense?

Verna

I have fiddled with the thought of purchasing two 6V AGM batteries (225 ah) and connecting to a separate inverter for my Dewalt scrollsaw, using my 200 watt Zamp solar suitcase to recharge the batteries. I camp all winter in a non-electric dispersed campground and this would allow me to “play” to my heart’s content. 

(I decided to purchase an antique 1884 treadle powered scrollsaw instead....but it was delivered in about 6 pieces....5 more than expected :( . I did receive all money back, thankfully, since I never got to use it.)

Olena

It would be nice to have separate power that is not linked to the T@B. I think I could justify a power source as a business expense, the T@B not so much.....

DougH

@pthomas745 : This old thread suggests the 12V sockets are 300W.  Maybe.  But different year models sometimes use 10A DC fuses on half the circuits, while others use 15A.

https://tab-rv.vanillacommunity.com/discussion/820/the-110-outlets

pthomas745

@Olena , I carry a 35AH AGM battery in a battery box and use it with an inverter attached to run my 45 watt laptop.  When it needs charging I attach my solar panel kit to it.  Like you, I wanted a separate power source.

What I've realized over time, though, is how hard it is to use up the 35 usable amp hours my stock battery allows me.  There is nothing inside the Tab that uses much power, and you would really have to go out of your way to use up 35 amp hours in a short period of time.   (I am assuming a propane fridge.)  The radio and television together are less than 1.5 amp hours.  The fan at highest speed is about 2.5, so you could run them all for 8 hours or so before hitting 35 amp hours.  If you just wanted to run the fan at the lowest speed you could run it for 35 hours straight!  (Your mileage may vary)!  My 100 watt solar panel keeps the battery up with the fan running all day and the laptop being used as needed.  ( I use the extra battery at night, mostly).

I don't know what you are sewing, but my guess the machine would not be in constant use for three hours straight, and your 120 watt panel would keep up with that level of battery use to some extent.

Read over Jenn Grover's blog concerning battery management.  She speaks highly of her Goal Zero equipment.

https://jenngrover.com/2015/11/guilty-as-charged-rv-battery-use-management/

Todd77

Any thoughts on using an Inergy Kodiak lithium battery and recharging with solar?  I have Zamp Solar panels, so I am not sure how easy it would be to recharge the battery that way.

dsfdogs

@Todd77 take a look at the Goal Zero Yeti 1000. They are at Costco for $999. This guy has a good comparison: https://www.youtube.com/watch?v=-2_Axz8IC4E

klenger

Regarding power use with a modern sewing machine, my wife has been sewing in our RVs for over 10 years.  The actual power consumption is actually quite low.  I can't assign a number to it, but with an efficient inverter, battery power is probably not a real big deal.  What we did find out is that Janet's Pfaff machine did not work correctly with a modified sine waver inverter.  Replacing it with a true sine wave inverter fixed the problem.  Here's the one I used in my T@B.

https://smile.amazon.com/gp/product/B00153EYX0/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

BrianZ

Apparently, electric motors need a true sine wave inverter, and I've read that peak power consumption at startup can be several times higher than at constant speed.
Seems like a second battery with a solar panel might be a good solution.

Here's what the labels on our converter show for the DC circuits & fuses..


Looks like 12V outlets are on a 15A fuse, but that's for all of them plus lights.

klenger

@BrianZ:  What model and year T@B are these pictures from?  I would like to update the wiring diagram on my website (see signature) with this information if it applies to reasonably new units.

pthomas745

@klenger I have a 2017 Outback and @BrianZ 's fuse list looks the same as mine:

dsfdogs

I have a 2018 and mine is different! As you can see, my label was hand-written and didn't include what each fuse was for, so I asked Creed. I typed up what he gave me and taped it in the lid. 

BrianZ

Interesting!
Ours is a 2018 320S, made in May, 2017, if I remember correctly.  We got it from a dealer in August, 2017, the day after the solar eclipse.

Ours may have been an early model, because NüCamp was in the process of switching from a 10A to a 7.5A fuse in circuit 5 to protect the SeeLevel display around that time.  I had a couple of discussions with them about it, because our cousins got the exact same T@B from the same dealer at the same time (a package deal), and theirs came with a 7.5A fuse where ours had a 10A fuse. 

NüCamp suggested we change to a 7.5A, since that's what SeeLevel needs, but since the pump manufacturer said it should be 10A, and both are on the same circuit, I did what both manufacturers recommended in their manuals and installed a relay switch after the SeeLevel's manual pump switch, with an in-line 7.5A fuse on the SeeLevel power line & split that power line before the fuse to send 10A to power the pump via the relay switch.  I strapped the 7.5A SeeLevel fuse to the plumbing vent pipe in the pump closet, & mounted the relay on the board next to the pump.  It's been working great for 1.5 yrs.

NüCamp didn't feel that the pump really needed a 10A fuse, since its performance graph showed it operates at around 6A or so.