Running Fridge on Battery |
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Kingskerswell
Senior Member Joined: 02 Oct 2018 Location: Kelowna BC Status: Offline Points: 141 |
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Posted: 10 Oct 2020 at 11:16pm |
We turn our fridge off when making a road trip to a camping destination as we don't like to run it on Propane when traveling. I know running the fridge previously on our 12V single battery resulted in a significant reduction to the charge status but I had not actually measured the extent. As we now have a solar panel and charge controller that has a good battery monitor I thought I would run a simple practical, albeit not very scientific, test as an indicator. After a 1.5 hr road trip the SP battery monitor indicated 72% battery charge status. Status at start was 100%. There would have been minimal solar charging as it was fairly overcast during the trip and I was not able to establish if the TV alternator contributed any charging. I will run a similar test next time we are out but the camping year may be at an end this year for us in BC. Equipment: 2013 RP177 HR 2018 Toyota Highlander Dual 6 V batteries in Series 160W SP |
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mcarter
Senior Member Joined: 12 Apr 2017 Location: Greenbrier, TN Status: Offline Points: 239 |
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I think it is important to know what the TV capability to charge is. As a start I would shut down 12V in TT, hook up TV and monitor TT battery charge with you monitor. I have noted many TVs are not capable of providing adequate charge, not wired adequately or not isolated adequately. The owners are unaware because they have not done what you are doing. Interesting project.
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Mike Carter
2015 178 |
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Kingskerswell
Senior Member Joined: 02 Oct 2018 Location: Kelowna BC Status: Offline Points: 141 |
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Update: Today I loaded the fully charged batteries by turning both furnace and fridge on for about 30 minutes, after disconnecting shore power. Battery voltage from SP (solar panel) monitor was 12.5V. I shut off the fridge and furnace then hooked up the TV 7pin connector to the TT, started TV and on idle and noted TT battery voltage at 13.5V. Increasing TV engine rpm to 3000 rpm did not change charge voltage. I don't have any way of checking the actual charge amps that the TV alternator is relaying to the TT so it is simply affirmation that the TV is delivering some sort of charge.
TT was under cover so no SP charge. This is just for information, as I will continue to turn off fridge when on the road for the most part unless our camping destination will have shore power hook ups but in that event I will monitor TT battery voltage to make sure the TT braking is not compromised.
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mcarter
Senior Member Joined: 12 Apr 2017 Location: Greenbrier, TN Status: Offline Points: 239 |
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Important to assume the TV does not charge to the TT requirement, it charges to the TV requirement.. no way it can identify the TV from the TT. There is some 12V feed to the TT but that is not how it is regulated. To allow a battery charge system to charge the TT above the TV requirement would require a battery to battery charge system from the TV to TT, which can be costly and is not how the system works. Charge is regulated by the TV battery from the TV alternator, that's it. The feed back to the TT is regulated by the TV charge system to the need of the TV battery.
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Mike Carter
2015 178 |
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Kingskerswell
Senior Member Joined: 02 Oct 2018 Location: Kelowna BC Status: Offline Points: 141 |
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Fridge on Battery Contd. - FYI
Just found the power rating for our Dometic fridge 130W @ 12V which I guess agrees somewhat with the 9.45A draw I am seeing on our SP controller (battery monitor). I guess I understand why many RV fridges today are 2-way mains/propane as opposed to 3-way to avoid beating up the battery. |
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