AC side leaking power?

[CortexConstruction]

I have a Van with 200AH lithium and 5000 watt inverter that I have isolated and tested by running 800w Hair dryer for over one hour. The van has 400W of solar and I have tested all and they are performing as advertised. The fridge, lighting and water pump all use DC. The battery recharges well on sunny day. The problem I have is that if I leave the AC inverter on the battery will drain without any AC load. I know the inverter has some loss but not enough to drain battery in a day or so with no load. Is there something I can test or monitor to find out what is going on?

Thanks in advance.

 

[BentleyJ]

Is it a 12V system? Its surprising how fast Amp hours add up with relatively small parasitic stand by loads.
As an example lets assume the inverter has a 48W standby loss. That is 4A at 12V. In 24 hrs, 96Ah which is more than 1/2 of the usable battery capacity.

Best way to find out is to disconnect all AC loads or use a meter to verify there is zero current going out to loads. Then use the meter and test the DC current being supplied to the inverter. That will tell you exactly what the stand by power waste is.

 

[CortexConstruction]

Its 12V. I have a multimeters but not a clamp meter.

 

[BentleyJ]

If the multimeter has 10A DC setting, current can be measured directly by putting the meter in series with one of the inverter battery cables. Certainly shouldn't be more than 10A draw.

Worst case, a $15 fuse in the meter gets wasted. Ask me how I know what they cost!

 

[CortexConstruction]

Ordered a loop. lets see.

 

[crossy]

Whilst waiting for your loop tester could you let us know the make and model of your inverter, someone may have actually measured the standby drain.

You did verify that your ordered loop-tester does to DC current, not all do!

 

[Steve_S]

An inverter can waste quite a bit depending on Make & Model. TBH, lower cost models are usually less efficient and have a higher standby/idle power consumption. Then of course the inevitable things like wall-warts and the things we never really consider can add up fast ! (death by a thousand bites, as it were).

 

[CortexConstruction]

The inverter is a Potek 3000. I dont see any draw on AC side. The DC numbers are as advertised (600W solar, 200AH Lipo) I also have a Renolgy DC to DC charger hooked to van alternator for insurance. I have not tried to disconnect or isolate the Renology to make sure its working correctly. I have the inverter turned on now to see if it drains battery then I will disconnect solar input and see what charger is putting out.

Right not I am only trying to keep a DC powered fridge running.

 

[Steve_S]

There appears to be 2 different models - differentiated by colour but nothing else different it seems. Sadly it is pretty short on details like idle/standby consumption.

Regarding Lithium Batteries.
LFP = LiFePo4 (Lithium Iron Phosphate chemistry)
LiPo = lithium-ion polymer.
These are different chemistries with different voltage curves and not interchangeable. The most common & safest ones in use are LFP which is also most likely what you have.

If you are running other "devices" off the Battery 12V, like a Fridge, that will certainly take it's toll as well.

Specification​

Nominal input voltage: 12.8~13.2 VDC
Operating input voltage: 10-15 VDC
Nominal output voltage: 115 +/-10V AC
Continuous output power: Up to 3000W
Surge output power (0.1 second): 6000W
Input overvoltage shutdown: 16±0.5VDC
Input undervoltage alarm: 10.5±0.5VDC
Input low voltage shutdown: 10±0.5VDC
Operating ambient tempreture range:32-104 F
Output wave: Modified sine wave
Internal fuse: 40Ax8
USB port:DC 5V/2A
Size: 10.4X13.3X4.6 inch
Weight:11.094 Ib

Packing List​

1 x Potek 3000W Power Inverter
4 x Car Battery Cables
1 X Earth Wire
1 x User manual

Notes:​

● Potek also has the Red 3000 watt power inverter on sale now. Check it out.
● Warranty: 18-month
● please use the battery clamp cable with a connection directly to the 12V battery while you run any loads higher 150W but lower than 500W.
● Do not use high power electric devices such as hair dryers, electric heaters, curling irons, vacuum connect the inverter to a battery.
● Please do not leave the power inverter in the ON position while your car is off.
● Disconnect the positive battery terminal before doing any wiring to the inverter.
● Keep the unit away from water and flammable material or in any location which may accumulate flammable fumes or gases.
● To reduce the risk of electric shock, unplug the unit from the outlet before attempting any maintenance or cleaning. Turning off controls will not reduce this risk.
● The inverter draws low amperage from the battery with the main ON/OFF switch turned on and no load connected. To prevent battery discharge, turn the inverter off when you are not using it.
● Only connect the power inverter to a 12V battery or power supply.
● Do not let the inverter into sunlight directly, keep it in a cool environment.
● Don’t use the inverter with a product that draws a higher wattage the inverter can provide, as this may cause damage to the inverter and product.

 

[Vigo]

If the multimeter has 10A DC setting, current can be measured directly by putting the meter in series with one of the inverter battery cables. Certainly shouldn't be more than 10A draw.

Not exactly true. Inverters have large banks of capacitors on their inputs and will momentarily flow a huge 'inrush current' when initially hooked to battery. So unless you did something to 'precharge' the inverter input side, you would certainly pop a 10a meter fuse trying to put it in series between the battery and inverter.

Not impossible, just requires a small extra step.

BTW, cheapest DC clamp meters ive seen on Amazon are around $30. Well worth it!!

My 5000w MSW 12v inverter has about a 6w idle draw. Generally speaking i never turn it off. If it was 50w i'd think about it!

 

[CortexConstruction]

Your right about most meters wont read DC with Loop. Ordered 2 from amazon only to find they only read DC with leads. What is the most practical way to measure DC pass thru?