Help: Inverter Problem

[kjlarson]

I have a 2020 Kodiak UL 201QB in which I installed an AIMS 2000 watt (4000 watt surge) inverter to run a Keurig coffee pot (800 watt/7 amp), toaster (750 watt/ 6.6 amp) and the microwave (1135 Watt/10 amp). When I got the inverter I set it up on my workbench, connected a spare 12Vdc battery and a standard house outlet on the 120 Vac inverter output terminals. Turned the inverter on and tested it with the coffee pot and toaster; both worked as expected. Installed the inverter in the TT, disconnected the 12Vdc positive and negative connections in the power panel (WAFCO 8955 PEC) and connected them to the inverter. Jumpered the inverter dc inputs to the power panel using 10 AWG wire. Disconnected the MBA (Main board assembly) from the power panel 120 Vac breaker so that it would not attempt to charge the batteries when on inverter power and routed a 10 AWG wire from the MBA to the shore power input at the inverter so the MBA would only come on when connected to shore power. Turned the inverter on and checked all the outlets which showed 120Vac on each. Plugged in my CPAP and it worked, turned the TV on and it worked. Plugged in the Keurig and toaster and they both did not work. Tried the microwave and it ran for about 2 seconds. In each case the inverter shut off almost immediately when attempting to use the appliances. Possible overload but cannot determine the source. Turned all circuit breakers off except the outlets and had the same results. Talked to AIMS support who guided me through some tests and they said that the problem was probably in the TT wiring. Neither the GFCI or circuit breaker for the outlets tripped. The circuit breaker in the inverter did not trip; it just shut off.

I have three 100ah deep cycle RV AGM batteries so should have plenty of DC power. Dutchmen ran 6 AWG wiring from the battery bank to the power panel which I used as stated above, could that wire be too small?

I would appreciate any ideas as to what what else I could check when everything seems to be within the specs of the inverter.

[persistent]

Length and size of wire is vital to function when operating at full power. 6awg wire is too small in any case. Get the wire tables for your inverter (see installation instructions). Choose wire size based on current and distance. 2000 watts will draw more than 170 amps from the 12 volt batteries. That is way to much for 6 gauge wire.

[kjlarson]

I suspected that might be the case.

[ewarnerusa]

I'm shocked that the manufacturer even used 6 gauge. I think mine is 10 or 12 from battery to control panel? My inverter is installed with 2 gauge at about 5' wire length from batteries. Still can't run my microwave, but probably due to insufficient battery capacity (2x6V GC batteries).

[hognuts1960]

Originally Posted by ewarnerusa

I'm shocked that the manufacturer even used 6 gauge. I think mine is 10 or 12 from battery to control panel? My inverter is installed with 2 gauge at about 5' wire length from batteries. Still can't run my microwave, but probably due to insufficient battery capacity (2x6V GC batteries).

If you don't know the lower the number the thicker the wire is.

[ewarnerusa]

Originally Posted by hognuts1960

If you don't know the lower the number the thicker the wire is.

Yes exactly. The mfg would default to cheapest and easiest, which would be thinner stuff.

[persistent]

Originally Posted by ewarnerusa

Yes exactly. The mfg would default to cheapest and easiest, which would be thinner stuff.

Actually, my limited survey of wire size in new cheap TT's shows the mfg use generally recommended wire size.

All 120 volt wiring appears to meet national code at some level. (Some new code requirements have not been accepted in many regions.)

12 volt wiring appears to exceed many automotive company practices. Helter skelter wiring routes through the TT seems to be rampant. But, wire gauge tends to meet requirements.

My Kodiak Cub came with 6 gauge positive cable from front battery box to rear converter/charger. That would be correct for that distance charging at 30 amps. 10 gauge wire has the ampacity to carry 30 amps. However, the distance for charging required larger gauge to reduce voltage drop. 10 gauge would be sufficient for about 2 feet.

The 6 gauge in the OP's TT appears to be correct for it's original purpose. It is not adequate for it's new purpose.

I wish you all happy holidays!

[VCToyhauler]

Originally Posted by kjlarson

I have a 2020 Kodiak UL 201QB in which I installed an AIMS 2000 watt (4000 watt surge) inverter to run a Keurig coffee pot (800 watt/7 amp), toaster (750 watt/ 6.6 amp) and the microwave (1135 Watt/10 amp). When I got the inverter I set it up on my workbench, connected a spare 12Vdc battery and a standard house outlet on the 120 Vac inverter output terminals. Turned the inverter on and tested it with the coffee pot and toaster; both worked as expected. Installed the inverter in the TT, disconnected the 12Vdc positive and negative connections in the power panel (WAFCO 8955 PEC) and connected them to the inverter. Jumpered the inverter dc inputs to the power panel using 10 AWG wire. Disconnected the MBA (Main board assembly) from the power panel 120 Vac breaker so that it would not attempt to charge the batteries when on inverter power and routed a 10 AWG wire from the MBA to the shore power input at the inverter so the MBA would only come on when connected to shore power. Turned the inverter on and checked all the outlets which showed 120Vac on each. Plugged in my CPAP and it worked, turned the TV on and it worked. Plugged in the Keurig and toaster and they both did not work. Tried the microwave and it ran for about 2 seconds. In each case the inverter shut off almost immediately when attempting to use the appliances. Possible overload but cannot determine the source. Turned all circuit breakers off except the outlets and had the same results. Talked to AIMS support who guided me through some tests and they said that the problem was probably in the TT wiring. Neither the GFCI or circuit breaker for the outlets tripped. The circuit breaker in the inverter did not trip; it just shut off.

I have three 100ah deep cycle RV AGM batteries so should have plenty of DC power. Dutchmen ran 6 AWG wiring from the battery bank to the power panel which I used as stated above, could that wire be too small?

I would appreciate any ideas as to what what else I could check when everything seems to be within the specs of the inverter.

>> You would think that would be enough DC, but it may not have had enough reserve to drive the inverter at full capacity. See if you have room for 4x6v, like this:

[rich2481]

I bought the biggest jumper cables I could find, cut the clips off and used that for wiring. CPAP can use a DC input but I use the inverter, i will say the inverter sucks power all the time, so used 50% of battery nightly. with only cpap. ( boondocking )

[franktafl]

Originally Posted by rich2481

I bought the biggest jumper cables I could find, cut the clips off and used that for wiring. CPAP can use a DC input but I use the inverter, i will say the inverter sucks power all the time, so used 50% of battery nightly. with only cpap. ( boondocking )

If you are near somewhere that sells welding supplies, go there for heavy duty DC stranded cables also.

[franktafl]

Originally Posted by franktafl

If you are near somewhere that sells welding supplies, go there for heavy duty DC stranded cables also.

They may also have the crimper for the BURNDY connectors (highly recommend) that you could rent or they may crimp them on for you once you get your cable lengths measured and cut. They also may be able to cut the cables for you (takes a special cutting tool to get the ends straight).

[kjlarson]

Thank you to all that replied for the very helpful feedback.

I have relocated the inverter to the forward storage area next to the two batteries in there. I ran 8/2 w ground for the 120Vac connections from the shore power to the inverter and back to the power panel. I ran 2 AWG from the positive of my bank to the inverter (<5 feet) and from bank negative to the inverter (< 3 feet). Took a couple of days to do this as the underside of my trailer is enclosed; so, I had to open it up to run the wiring.

As to the 6 AWG the factory installed between the power panel and the batteries it is now used exclusively for charging the batteries. As mentioned originally I rewired the 120Vac to the MBA which contains the charger to come on only when connected to external power. The charger is a multistage charger putting out 55 amps which the 6 AWG handles just fine. When connected to shore power the MBA supplies both the 12Vdc and battery charging. The inverter is turned off when on shore power.

Next year: Solar.

[persistent]

You can order cables cut to size and with crimped connectors. Amazon and others sell these custom cables. They are available cut to size or with connectors. You must get the specifications right. Heavy copper cables cost plenty with or without custom cutting.

Cables and connectors designed for welding are an excellent choice for RV high current use. They are widely available. Automotive starter cables are next best. You can get them with connectors at hardware stores or auto stores. Places like O'reilly's or NAPA may cut to length and crimp connectors.

Size of screws to be used on each end is important as is length. Copper lugs are the best value for high current in non-corrosive atmospheres. Plated is next best for battery compartments. Gold platting is better than other platting, but costs quit a bit. The contact surface resistance makes a big difference. Gold is the best.

Lead solder is a poor conductor so "potted" connectors should be avoided. Silver solder is better, but still distinctly worse than crimped copper. All good soldering technique requires a good mechanical connection before soldering. Crimping can provide that, but then there is no need for solder and crimping withstands vibration better. Soldered joints should be supported near the joint to prevent flexing when vibration or movement is present.

Corrosion protection is required in corrosive environments. Grease is often used for underground splicing. There are many marine and other corrosion prevention treatments. Marine are usually better the automotive, but grease is all it takes.

Be careful when buying jumper cables for high current applications. They are often mostly thick plastic coated with small copper core. The very best probably cost more than custom cut welding cable. The cheap ones are frequently worthless for battery charging.

I wish you good luck and happy trails ahead!