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Refrigerator on propane or using an inverter to provide elec

Posted: Tue Jun 12, 2018 2:09 am
by Dallas Baillio
I’ve always operated my refrigerator on propane even when connected to shore power or operating the generator. I have now done extensive maintenance and upgrades to my BF. Now that I can have electrical through a newly installed inverter / converter is it a better idea to use electrical only? Is the current draw so strong for the refrigerator that boondocking overnight would quickly discharge my batteries? I will appreciate whatever y’all have to offer. I know that some of you regard using propane as a serious safety issue. Let’s leave that out of the discussion for now. I really want to know if electrical is a good solution other than from a safety standpoint.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jun 12, 2018 6:24 am
by Roger H
If you have the standard two-way 110AC/propane fridge, I'd run it on propane if you're boondocking. When on shore power, run it on 110AC. Your 110AC heating element will drain your batteries pretty quickly using an inverter. I wouldn't recommend it.

I know there have been great strides in efficiency in the marine compressor 12v refrigerators, and many of the late-model B-vans out there are coming out with huge battery banks and inverters to do away with propane, but for our vintage of coach, there's not much reason to retro-fit them or try to do alternative energy sources unless you have some special need. And, in our risk-averse society the "threats" that propane represents are significantly over-blown. Motor vehicles can and do catch fire and explode at gas pumps as well, yet THAT threat isn't discussed much... and propane and gasoline incidents likely happen at about the same rate. When used properly propane has been and remains a safe energy source in millions of RVs and homes.

Quite honestly, you're MUCH more likely to be hurt or killed in a home bathroom fall or a car accident. Just use your propane, and don't worry about it.

Likely just changing out the bulbs to LEDs is probably the single biggest battery-extender you can do.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 4:16 pm
by Vlamgat
Just seems to me that running down the highway literally inches from 18 wheelers who may have to hook a turn at any moment with a naked flame burning - is not preferable.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 5:24 pm
by whemme
Well if you are boondocking or running down the highway you really don't have much choice to operate your two-way refirgerator - will need to power it in LP mode. If you install a powerful enough inverter to power the refrigerator in AC mode using your coach batteries as the source of power, the high current required will discharge your batteries quickly.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 6:35 pm
by Vlamgat
My coach batteries are charged by the van alternators and so far, after 12 years, no problem. What really kills my battery is the coach a/c start even on a generator. Going to try the Easystart that has recently been released and designed to make the Honda 2000 generator compatible with RV a/cm

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 7:00 pm
by whemme
Guess I don't understand why running you coach's air conditioner using your installed generator is hard on your coach's batteries. The energy to run the AC is coming from the coach's fuel supply, not from you batteries. Please explain further. Also don't know what you mean by RV a/cm?

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 7:49 pm
by Vlamgat
The rv a/c start amperage is about 40 amps which is all the generator (when using the Honda) and the investor can provide. The constant cycling of these starts in the summer taxes the battery which cannot recharge the investor and itself from the limited amperage of the Honda. I use the Honda because it's quiet, can be positioned away from the rv and saves me limited availability diesel which is also more expensive.
Typo, meant to say rv a/c.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 8:14 pm
by whemme
Well, when I am running my A/C running the on board Onan generator, I leave the A/C and generator running full time eliminating the problem of constantly having to restart the generator. Can't you do the same thing with your remote Honda generator?

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 9:40 pm
by Vlamgat
The Honda runs all the time and has an extended fuel tank. Problem is still not enough amperage to restore the battery fas enough to handle the attrition caused by cycle after cycle. I have had some success prolonging battery life by setting the thermostat to Low so that once it starts the compressor, it remains running until the ambient becomes livable at 2 am. This is not always viable and I never know when the battery will fail. This is evidenced by insufficient amperage to sustain a restart.

Re: Refrigerator on propane or using an inverter to provide

Posted: Tue Jul 10, 2018 10:56 pm
by whemme
Vlamgat,

You did not identify your type and year motorcoach. If it is a Born Free, it is will be equipped with a charger/converter that would recharge your house battery anytime your builtin generator is running or even if your external Honda generator is is plugged into the coach via the normal shoreline power cord. However, in an earlier post you seemed to indicate that you may have a conversion van that only recharges your house battery when the coach engine is running and being charged by the alternators (do you mean you have two alternators?). If in fact your are restricted to charging your battery only via your van's engine, I can see your charging problem. Let me know your model and year of motorcoach and if it is equipped with a larger/converter.

Re: Refrigerator on propane or using an inverter to provide

Posted: Wed Jul 11, 2018 8:31 am
by Vlamgat
I have 2 coaches with the same problem but different magnitude: a 2014 BF Triumph and a 2000 Sportsmobile. The point you are missing as simply as I can express it is that the drain on the battery to effect an a/c start is so significant and happens so often that the surplus amperage available while running the Honda is insufficient to fully recharge the battery sets. The charger converters on both coaches draw battery power to recharge the inverter after the a/c starts. Once that is accomplished which takes a minute in the BF and as much as 5 to 10 in the SMB, the charger then draws what it can from the Honda to recharge the battery that was drawn heavily by the inverter and a/c start. Once or twice is no big deal. All day with as many as 40 or 60 of these cycles results in the battery gradually discharging. Although it may recover as the evening progresses and the direct sun is eliminated, the battery is damaged and its replacement is going to have to be made in 12 months (SMB) or 24 for the BF. Of course with the BF I can run the built in generator and do so after 1 pm. No such option with the SMB except run the main engine. I have also noticed that when plugged to 30 amp shore power, both coaches dip into the inverter capacity whenever the a/c starts. That's why I am hopeful that the Airstream experience with the Easystart device will eliminate or substantially reduce the problem as it reduces the start amperage for a/c to about 15 amps from an observed 42 amps.

Re: Refrigerator on propane or using an inverter to provide

Posted: Wed Jul 11, 2018 11:07 am
by whemme
I am trying my best to help you but I think we are misunderstanding each other's terminology. You state the following in your post above: The charger converters on both coaches draw battery power to recharge the inverter after the a/c starts.

There is no such thing has recharging an inverter, the only thing getting recharged are your house batteries and those will be recharged via the charger/converter and not an inverter if in fact you are equipped with one of those optional devices.

The older Born Free coaches like mine were equipped with a single stage Parallax 7345 Charger/Converter. This single stage unit was very slow at recharging the batteries when either plugged into shoreline power or by running the generator - in fact it would take that charger/converter 21 hours to recharge depleted batteries back to a 90% recharge level. A modern 3-stage Progressive Dynamics PD4655V Charger/Converter recommended in the Coach Modifications section on this forum would reduce that long recharge time down to only 3 hours. Your 2014 Born Free should already be equipped with one of those type 3-stage charger/converters. If not, I would highly recommend installing one.

As long as your built in generator or remote Honda generator is running up to full speed and running your A/C, whatever charger/converter you have will be delivering its full capable battery recharging current. There is no way for the system divert some of the generator's output current away from to charger/converter to supply full current to the A/C. If the current requirements to run both the charger/converter and you A/C is more than your Honda generator can supply, then the output circuit breaker on the Honda should open.

Your best bet to keep your batteries charged up while running your Honda generator is to be equipped with a 3-stage charger/converter and if your coaches are also so equipped, make sure they are operating in all three modes properly. Fast charge mode charge voltage should be 14.4 vdc. Normal mode charge voltage should be 13.6 to 13.8 vdc. And maintenance mode charge voltage should be 13.2 vdc.

The other advantage of this type charger/converter is that you can be hooked up to shoreline power constantly without any risk of over-charging your batteries and boiling out the acid/water.

Re: Refrigerator on propane or using an inverter to provide

Posted: Wed Jul 11, 2018 11:47 am
by Mike Jean Bandfield
Bill,
I think he is saying the AC is being powered by the inverter, which draws down the batteries faster than the converter can recharge them - via generator or AC. This begs the questions: Why is the AC connected to the inverter when the coach is running on AC and what else is the inverter powering and how efficient is this very high powered inverter?

But I'm also confused by the 2 RV configurations and terminology ("investors" et al?)

Re: Refrigerator on propane or using an inverter to provide

Posted: Wed Jul 11, 2018 11:55 am
by Vlamgat
My inverters and I think all inverter ops are powered in part by condensers. These get depleted if the alternating current draw exceeds their storage capacity. This happens when the a/c starts. Once the condenser bank is recharged by the generator, current is available to restore the battery. I confess I am not sure if the generator restores the capacitor and then the battery, or the battery restores the capacitor but my observation of the draws during this process seems to indicate that it's the latter.

As for the overload function on the Honda, this does indeed work and after a the several morning cycles, and as the battery deteriorates, the overload cuts in earlier and earlier in the day. This has signal led to me that the battery is not able to sustain the load on the capacitor during start because it was not sufficiently recharged from the previous start ( s) and or it cannot hold a full charge any longer. This is a process that has evolved over the life of 5 SMB batteries and 2 sets of BF units as well as 2 Honda generators. I have had no problems running a pair of Hondas in parallel but neither coach has room to store 2 of these without the risk of an interior missile in an accident situation. Besides which it's been challenging to keep one running for 18 hours let alone 2. Both convertor, charger, investor units are 3 stage systems and work as designed as long as they are not powered solely by a single Honda. The Airstream forum validates my experiences and their subsequent successes with the Easystart device.

Re: Refrigerator on propane or using an inverter to provide

Posted: Wed Jul 11, 2018 12:00 pm
by whemme
Well I guess I never heard of a situation where an inverter was employed to run an A/C. If in fact that is the case it would require an 6000 watt rated inverter assuming the A/C draws about 20 amps to run it. That would require a current draw in excess of 400 amps from the house batteries which would deplete them in around only 20 minutes. So I really doubt that an inverter would be employed to run the A/C.