Inverter question

We're running our freezer on an 800 watt inverter. But, we do have additional batteries and solar. However, as previously stated, while traveling, your vehicle should maintain your batteries in rv. If the freezer is kept cold (using shore power while at a campground), the amp draw should be minimal while traveling! memtb

theoldwizard1 wrote:

GordonThree wrote:

theoldwizard1 wrote:
Your batteries won't go dead, but they will not be fully recharged even after driving all day.

This has been my experience too.

If your goal is to recharge your battery bank while driving from one boondock location to another, this is a difficult problem to solve !


This going to sound really silly but ... assuming you already have a good charger on your trailer, buy a separate inverter and install it inside the tow vehicle, but as close as is reasonable to the battery. Wire it through a relay that is activated by "KEY ON" power. Run an extension cord back to the charger in the trailer.

If you have a 120V refrigerator/freezer connect the output of the tow vehicle's inverter to the shore power wiring, and turn off the TT inverter.

If you are a bit of a electronic widget geek, like myself, you can use one inverter by moving it back and forth. Use Anderson Powerpole connector for the DC input and some way of quick but firmly mounting the inverter to either the TT floor or tow vehicle floor !

I extended my shore cord so it can reach the truck bed. Then I run my generator in the truck bed. Works great to recharge after an overnight at Walmart, etc.

I agree, using 120 VAC is a lot more effective means to transfer energy between the tow vehicle and trailer.

Tundra, this would depend on a number of factors. Temp, battery size, freezer wattage. Freezers don't run all the time, depends on the temp.

You might be able to get a decent idea on how much it uses by hooking up a Kill A Watt usage meter for a couple days with the freezer in it's normal fill level and it already at temp. Good hardware stores carry them. Being March, you may want to bring the freezer in the house to try it although even that won't simulate a 90 degree day. Using an hours average wattage you can get an estimate of how long your battery will last, at whatever ambient temp you test it at, not counting any input from the tow vehicle.

GordonThree wrote:

theoldwizard1 wrote:
Your batteries won't go dead, but they will not be fully recharged even after driving all day.

This has been my experience too.

If your goal is to recharge your battery bank while driving from one boondock location to another, this is a difficult problem to solve !

The other possibility is to get a DC-DC boost converter (not too expensive on eBay) and install it between the TT 12V input from the tow vehicle and the inverter. Do NOT connect this to the rest of the TTs 12V system, just the inverter. Set the output voltage for about 14V. The battery charger should get "shore power" from the inverter and charge the batteries.

GordonThree wrote:

theoldwizard1 wrote:
Your batteries won't go dead, but they will not be fully recharged even after driving all day.

This has been my experience too.

If your goal is to recharge your battery bank while driving from one boondock location to another, this is a difficult problem to solve !


This going to sound really silly but ... assuming you already have a good charger on your trailer, buy a separate inverter and install it inside the tow vehicle, but as close as is reasonable to the battery. Wire it through a relay that is activated by "KEY ON" power. Run an extension cord back to the charger in the trailer.

If you have a 120V refrigerator/freezer connect the output of the tow vehicle's inverter to the shore power wiring, and turn off the TT inverter.

If you are a bit of a electronic widget geek, like myself, you can use one inverter by moving it back and forth. Use Anderson Powerpole connector for the DC input and some way of quick but firmly mounting the inverter to either the TT floor or tow vehicle floor !

5 CU FT freezer,often drove 9/10 hours,never a problem .

Just a hair under 72 hours, without being plugged in, and our small 4.0 cu ft deep freeze kept everything frozen solid. I don't kn ow for how much longer it would have been safe, nor do i ever again plan on extending our luck for that long with frozen food in the freezer. Of course, YMMV. How long would you normally be travelling for without being able to plug in the freezer?

Cheers!

Mike

theoldwizard1 wrote:
Charging a TT battery bank while driving is a very hit and miss situation. Modern vehicles do not charge at a very high voltage (13.2V-13.6V) and by the end of the wire in your TT it is probably going to be less than 13.0V. Your batteries won't go dead, but they will not be fully recharged even after driving all day.

This has been my experience too.

Charging a TT battery bank while driving is a very hit and miss situation. Modern vehicles do not charge at a very high voltage (13.2V-13.6V) and by the end of the wire in your TT it is probably going to be less than 13.0V. Your batteries won't go dead, but they will not be fully recharged even after driving all day.

Yes IMO a 1000 watt rated sine wave inverter should start and run the freezer while on the road. Most of the energy will come from the tow vehicle. Worst case the battery will be a bit low on arrival and will charge back up when you plug in.

Extended stop without power or overnight without power I recommend at least two batteries.