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Old 01-11-2019, 04:02 PM   #41
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Coachmen is now offering a 12 Volt Rooftop A/C on the Crossfit. There was a video posted by The Fit Rv showing that the AC unit was only drawing about 30 amps @12 volts.

It looks like with this unit you can more than double the AC run time. The list price for this upgrade was around $3600.
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Old 01-11-2019, 04:23 PM   #42
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Coachmen is now offering a 12 Volt Rooftop A/C on the Crossfit. There was a video posted by The Fit Rv showing that the AC unit was only drawing about 30 amps @12 volts.

It looks like with this unit you can more than double the AC run time. The list price for this upgrade was around $3600.
Wow! That would be worth it.
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Old 01-11-2019, 04:24 PM   #43
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I am at the same place as you. I have read where the Volta system in the Travato will run the AC 6 to 7 hours on batteries and recharging in 1.5 hrs where the Li3 will only go 3 to 4 hrs and recharging 2.5 hrs. That's where I am struggling with the decision.
Yeah that is not long enough for what I need. Let us know what you decide to do.
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Old 01-11-2019, 05:16 PM   #44
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The whole Li3 issue of $20K sort of irritates me anyway. I do this stuff for a living. My last design has an Li battery and smart charger. The battery pack contains all of the safety circuitry as well as the battery. This is the only way to get them these days for safety reasons, i.e., Samsung phones. We buy the battery pack for a little under $2.00. The charger we buy from Linear Technology for 95 cents. There are a few cents worth of resistors and capacitors in the circuity. The charger rates are controlled by a small micro controller that cost less than $3.00. The case of the design doubles as the heat sink. I wrote the firmware that monitors all of this in less than 4 hours. So, this is small battery (2.7Ahr) and charger (1A max) for a small system, but all the electronic principles are exactly the same. If you scale it up to a 400Ahr system, it is nowhere close to even $2K. Just how much money do the RV builders need to make? I bought the resonator form Cummings. It does cut the higher frequency barking of the Onan quite a bit.
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Old 01-11-2019, 06:30 PM   #45
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The whole Li3 issue of $20K sort of irritates me anyway. I do this stuff for a living. My last design has an Li battery and smart charger. The battery pack contains all of the safety circuitry as well as the battery. This is the only way to get them these days for safety reasons, i.e., Samsung phones. We buy the battery pack for a little under $2.00. The charger we buy from Linear Technology for 95 cents. There are a few cents worth of resistors and capacitors in the circuity. The charger rates are controlled by a small micro controller that cost less than $3.00. The case of the design doubles as the heat sink. I wrote the firmware that monitors all of this in less than 4 hours. So, this is small battery (2.7Ahr) and charger (1A max) for a small system, but all the electronic principles are exactly the same. If you scale it up to a 400Ahr system, it is nowhere close to even $2K. Just how much money do the RV builders need to make? I bought the resonator form Cummings. It does cut the higher frequency barking of the Onan quite a bit.
I agree with you. If it was the same price as a generator or slightly more I could see the justification, but $20K? Maybe if it ran things like AC for days, but we are talking 3 to 4 hours.
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Old 01-12-2019, 02:42 AM   #46
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Which one is safer? No brainer, the Coachmen Li3 is UL approved and will not burn your RV down in a accident. Best Lithium battery available.
I have seen tests where the Li3 gets 8 hours of A/C usage, but it all depends on conditions.
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Old 01-16-2019, 04:52 PM   #47
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Li3 states 8 hours of A/C use, straight from Xentrex.
In my research the only system UL has approved for safety reasons is the Li3 Lithium.
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Old 01-16-2019, 05:14 PM   #48
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Which one is safer? No brainer, the Coachmen Li3 is UL approved and will not burn your RV down in a accident. Best Lithium battery available.
I have seen tests where the Li3 gets 8 hours of A/C usage, but it all depends on conditions.

Watt-hours are what counts, IMO. And that has to be usable watt-hours not just rated battery watt-hours before the safety cushions are added. Comparing other ways that vary, like conditions just encourages the misrepresentations by the sellers.



Obviously, the conditions make a difference, and that is exactly why stating running hours is a very poor comparison of battery designs. Heck if it is cool enough out, I can run the AC off a tiny battery because it is never on, as a gross exaggeration.
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Old 01-16-2019, 08:58 PM   #49
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Li3 reads out both watt hours and amp hours, both coming in and out or what the watt hour level is at live.
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Old 01-16-2019, 09:05 PM   #50
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Li3 reads out both watt hours and amp hours, both coming in and out or what the watt hour level is at live.

And that is a good thing. What it doesn't do is make using how many hours claimed to run AC a valid comparison. The AC running has turned into a nearly pure marketing ploy, IMO, and marketing has been exaggerating it ever since the original etrek claims that were soon proved to be untrue.
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