Inverter vs Mr Coffee

edjahar42 · 07-03-2011, 04:57 PM

My 94 PaceArrow has a 2001 Heart Interface 1800 HD inverter. I just installed four new golfcart batteries and charged them with the inverter overnight. All my cable connections from batteries to inverter are clean and tight.
I can run tv and other light loads but the coffee maker and microwave cause it to shutdown. This is the first time I've tried to use the inverter, I tried once and it wouldn't power anything, so I blamed the batteries?
Appreciate any help,
Ed

docj · 07-03-2011, 05:10 PM

Both your coffee maker and microwave probably draw close to the inverter's maximum power output even when they are operating on regular AC power. I believe they may draw even more power when you are using a modified sine wave inverter like you have. IMHO the problem isn't batteries, but the inverter's limited output.

edjahar42 · 07-03-2011, 05:38 PM

Thanks, looks like I'll be using it just for tv and maybe a fan.

**RJay** · 07-03-2011, 05:45 PM

Your inverter is rated for 15 amps. The coffee pot and microwave is about 10-12 amps each.

BigV · 07-04-2011, 09:09 AM

What size and length are the cables used to connect the inverter to the battery bank?

tvman44 · 07-04-2011, 09:15 AM

Don't know for sure but going by the model # I would guess that inverter is rated for 1800 watts peak and 900 watts constant, in that case you need a larger inverter.

**Gary RVRoamer** · 07-04-2011, 09:50 AM

Typically if Xantrex/Heart uses a model number of 1800, it means it can handle 1800 Watts constant and double that for very short periods. That's not so true of other brands, but Xantrex/Heart is usually honest on that score.

**RJay** · 07-04-2011, 10:48 AM

All inverters have an efficiency rating falling somewhere between 80 to 90%. The more expensive inverters have a higher efficiency. Assuming an efficiency of 90% for the OP's inverter the most that can be expected at the output is 13-14 amps continuous and 27 amps short time.

edjahar42 · 07-04-2011, 11:57 AM

Just out of curiosity, what size inverters do you guys have and what do you run on it?

bluepill · 07-04-2011, 12:32 PM

2000 watt MSW. Microwave, coffee maker, hair dryer, toaster, toaster oven - Only one at a time with nothing else on.

Usually fire up the 8000 watt genny if it's more than a few minutes use - Don't like to push the inverter near its limit.

TV's, laptop chargers - no restrictions.

coburncliff · 07-04-2011, 05:42 PM

I have a similar problem. I'm suspecting my shore power though. The warmer the temp (more AC's running=brownout) the more often my breaker trips. (Lower voltage=higher current.) I'm going to tear the electrical system apart and try to re-balance the load. It looks like someone replaced the inverter in the past so I have no idea how close to the original schematics/drawings it may be. I'm at work and my significant other just texted it's 102º outside and she can't keep the AC running. Guess this project will be moved to the front burner.

Dav5942 · 07-04-2011, 05:56 PM

Also you can get a GE coffee maker that draws 6 amps!

wa8yxm · 07-04-2011, 06:51 PM

Quote:

Originally Posted by RJay

All inverters have an efficiency rating falling somewhere between 80 to 90%. The more expensive inverters have a higher efficiency. Assuming an efficiency of 90% for the OP's inverter the most that can be expected at the output is 13-14 amps continuous and 27 amps short time.

It is amazing some of the things I see here.

Yes, 90 percent it typical of inverter efficenties

That does not mean that I should multiply my Prosine 2.0's rated 2000 by 90 percent to get 1800 max. It means that if it's sucking 2200 watts out of the batteries,, It's delivering 1980 watts to the loads.

Work it out,

You have confused input with output.

For the original poster:

The microwave draws like 1100-1300 watts RUNNING, the starting surge can be a real kick but the inverter should haul the load.

The coffee maker is likely a few hundred watts less and again the initial surge, though longer, is way slower.

HOWEVER... I think 4/0 is the recommended short run 12 volt cable for my Prosine. your 1.8 kw should likely use about the same size. I deciced to upgrade my cable after some initial issues.

Go to the manual, measure your cable run, choose 1-2 sizes larger cable, TAPE THE TWO CABLES TOGETHER, run both cables back to the battery save for the Positve cable should run to a "T" fuse of the size specified in the manual near the battery. Keep the run as short as possible and keep the wires taped together as much as possible.

Beyond that clean all connections.. Note that at 1.8 KW.. two pair of golf car batteries in good condition might be a better idea.