2020 AS Inverter / Battery Issues-HELP!

[jjohnson2033]

Newbie here and need some help. We have a 2020 Flying Cloud and just returned from our first boondocking trip. Our AS has the factory installed 1000w inverter and 2 solar panels on the roof. We have the lead acid batteries that came with the AS. Problem we repeatedly experienced was when we turned on the inverter to use the coffee maker (or any small appliance) the inverter kept shutting off the appliance and seemed to be quickly drawing down the battery power. Not sure if the issue is with the inverter (the inverter never shut itself off) or with the batteries? I'm going to contact the service department at our dealer, but would like to have some idea if the batteries are the issue so I can decide on/purchase upgraded batteries before I talk to service. Any thoughts/help appreciated.

[BayouBiker]

You may want to check the appliances first. anything drawing more than 1000W / 8.3 Amps is going to overload the inverter. Our coffee maker is 1200W and the inverter will not power it. Stove coffee and no hair drier without a generator.....

If the inverter trips under 1000W your batteries may be weak, Since they are wet cell the cheapest most accurate and easiest way to test them is with a $10 hydrometer.

Edit: the stock wet cells if in good condition and 80% or more charged have plenty of capacity to run your inverter at 1000W.

[jjohnson2033]

Originally Posted by BayouBiker

You may want to check the appliances first. anything drawing more than 1000W / 8.3 Amps is going to overload the inverter. Our coffee maker is 1200W and the inverter will not power it. Stove coffee and no hair drier without a generator.....

If the inverter trips under 1000W your batteries may be weak, Since they are wet cell the cheapest most accurate and easiest way to test them is with a $10 hydrometer.

Edit: the stock wet cells if in good condition and 80% or more charged have plenty of capacity to run your inverter at 1000W.

Thanks for the quick reply. I checked the coffee maker and it in fact is 1200w so that one makes sense, but the electric tea pot is 800w so that one doesn't. I have no idea what a hydrometer is but will check it out. Thanks again

[Foiled Again]

When boondocking, propane is your "go to" for anything you want to heat up. The inverter will run low draw things like LED lights, a flat screen TV or a charger for a phone or computer. Anything that creates heat is high draw - electric skillet, coffee maker, etc. Your TOTAL draw is limited to 1000 watts, so an 800 watt teapot plus a computer and a TV... and pop goes the breaker.

Inverter is handy, but limited! And it does run down your batteries. Make sure you have your tow vehicle umbilical disconnected from your trailer or you might run down its battery too. (Some tow vehicles now have protection against that kind of draw, but it's a nasty surprise if yours does not.)

[BayouBiker]

A hydometer reads the specific gravity of liquids, it is useful for salt/acid solutions to test the strength of the solution. With batteries, the condition of the lead plates will relate to the degree of charge completeness and thus total capacity and condition. Complete charge maximizes acidity and weight of the solution. You can get a hydrometer online cheap and pick it up at the auto store or walmart or have it delivered. You fully charge the battery and then test each cell. They should all match closely and be close to the ideal 1.285. If they don't match each other or are not close to 1.285, Equalize charge the batteries at 14.6-15 volts for up to 14 hours. Every couple hours check the gravity and once it stops rising the batteries are at their limit.

[uncle_bob]

Hi

The inverter will trip out on "high load", on "low voltage" or "over temperature". There is a drop in the leads from the battery to the inverter. The more current you pull, the more the drop. As the voltage goes down, the current has to increase ( 800W at 10V is more current than 800W at 13.6V). If it's hot in the trailer or if the fan is full of crud, the device may get pretty warm pretty fast.

The inverter has a "1,000W" label on it. Inevitably, there is more to the spec than one simple number. What is the maximum input current? What is the efficiency at various loads? How long can it deliver this or that power level ( = surge) ? How much does temperate impact all this? Some devices have fairly detailed specs, others .... not so much.

Equally, your appliance has a label on it. The same basic issues apply. It *may* (though it should not) pull more current than the label indicates. The only way to know is to measure the current with a meter.

Some math:

If one *assumes* a 1KW load and 80% efficiency, that's 1.2KW into the device. At 12V that would be 100A. With a 1V drop in the wires you are at 11V and about 110A.

Lead acid batteries "like" to discharge small currents for a long time. Capacity / 20 is a small current in this context. 100A is up around capacity / 2. Your "160AH" (for the pair) battery bank is 160AH at C/20. at C/2 it might be half that or even less. Let's guess half and move on. The internal resistance of the battery also means lower output voltage at higher current.

If you only run to 50% capacity and start from 100%, your bank would be an 80AH bank. At
120A, you could run the loaded inverter for 45 minutes. This is going to be an over optimistic guess. The lower output voltage and wire heating probably will kill you around 30 minutes or less ...

So indeed, unless you have a fancy bunch of batteries, don't run the inverter at full load ....

Bob

[GMFL]

The factory system is not powerful enough to to do much more than watch a little TV or charge a Laptop. Your 1000w inverter as stated previously will shut down from to large of a load or low battery voltage.
Lead Acid batteries have a fairly high internal resistance, meaning they cannot release their stored energy very fast. This means that under high amp demands the voltage will drop quickly causing the system to “collapse”. Once the load is removed the batteries will recover some, but again will not support high demand loads.

[BayouBiker]

^ What GMFL said. A typical wet cell at 50 Amp draw will drop about 1 V so once the batteries are down to maybe 60% even a 800-900W device will be drawing enough on the 120 side to cause it to shut down. Great point!

[Atwebs]

Solar will run your lights and do some lightweight recharging, but as was mentioned it is not for everything. You can find low wattage coffee makers and hairdryers, but there are other options.

But, look into better batteries. Lithium are great, but even the AGM will be better for solar than the plain, old Interstates. Our last trailer (SOB) required battery replacement almost every single trip, even though we stored them on a fancy trickle charger, had a solar suitcase and monitored them regularly. Luckily, we learned Costco carried the Interstates and that made replacing them less painful.

Our Airstream dealer recommended the AGM batteries with our solar and they have worked first time, every time, no fuss and no emergency battery shopping trips. That's 2 full years with no issues at this point.

[226TuckL]

We have a 2020 Globetrotter and our batteries had problem holding a charge...According to our dealer turns out our batteries were “old” lead acid batteries and not AGM which are intended for AS solar. Dealer replaced batteries and problem solved.

[lkm4321]

When boondocking we put the electric coffee maker away and get out our old fashioned percalator and make our coffee on the stove. Different, but just as good - kinda like camping

[WindyJim]

We have two 6 volt Trojan lead acid batteries and 300 watts of solar, but we do not use these for high current drain items like the coffee pot, etc. As lkm4321 said, we use a nice stove-top percolator for coffee.


For high draw items we have a Goal Zero Yeti Lithium 1000 which has a 1500 watt pure sine wave inverter built in. When the wife wants toast or something we plug the toaster into it and make the toast. (The GZ1000's inverter is surge rated to 3000 watts, and I tried to load test it, and it lasted almost 30 seconds before it tripped out at 3000 watts.)


So the Yeti is used as a surge energy provider, and the solar serves to recharge both the trailer and the Yeti.


The future is definitely Lithium, but until my existing batteries fail in a few years, I'll keep using them. When one takes into account battery costs over a prolonged period of time, Lithium actually is the lowest cost because of it's longevity. It also far exceeds the surge capacity, etc. of lead acid or AGM batteries. Also, it is about half the weight of a lead acid battery.

[overlander63]

1000 inverted watts is about 100 amps. Since your batteries only hold a maximum of 160 amp hours, you're going to not accomplish much more than running your batteries dead. They are storage batteries, not a portable nuclear power supply.

[jjohnson2033]

Thanks for all the replies; the info is very helpful for understanding the limitations. One additional question related to AGM vs. lithium battery upgrade--in researching it seems going to lithium batteries involves more than just switching out the batteries correct? That a different battery monitoring system is also required? I know there are a lot of other threads on tradeoffs between the two (cost, etc.) but trying to distill it down.

[GMFL]

Adding lithium can be as simple as dropping in new batteries. With that said most factory chargers/ stock will only charge a lithium battery to 80% due to there lower voltage settings. By swapping out the factory charger (13.6 VDC) for a lithium charger (14.4VDC) you can then have a basic complete lithium system.
Swapping the charger/ converter is not hard and there are a few brands out there that are direct replacements for the factory system.
All other parts of your system will work fine.

Now...... there are define a few more “toys” that can help you have a better system like shunt based battery monitors, MPPT solar controllers, larger inverters, ect. (Rabbit Hole)

But for a basic system two lithium batteries and a new charger/converter and you are good to go!