battery disconnect switch (reality check!)

[Mike Jean Bandfield]

... now that I keep it here at the house and plugged in is the reason that the squeal just now appeared.
<snip>
Jack

Jack, your description of the BF setup and the AM squeal doesn't add up for me. Something could be wired wrong or the inverter is failing. If you are plugged into shore power at home, the inverter shoiuld not be tied into the AC. The inverter is likely connected to an automatic transfer switch that should only connect it in the absense of shore power or generator power. Is it continuously powered on the DC side? If it is indeed turned on at the same time you are connected to shore power, is there a possibility that it is back feeding your home wiring in some way? (But a condition like that should have been more like the 4th of July than just a little radio interference.) Is the transfer switch wired correctly? ...or is it failing? Did you possibly mean "converter" instead of "inverter"? Is the PD generating the RF interference? I'm confused.

Mike

PS. How many of your neighbors are on the same power transformer? I wouldn't be surprised if they are also experiencing RFI on their radio and TVs.

[bcope01]

I have also installed a precision coach battery voltage and current meter charge monitoring panel...

Bill, I installed a voltmeter too - a Datel LCD 2-wire digital DC voltmeter. The following pictures show the meter dimensions and the meter installed.

Bill

[lassen]

Bill Hemme....The Inverter is a Cobra CPI 400 that was Born Free original equiptment on the 2005 coach. The booklet states that its a 400 watt modified sine wave.

Jack...

[whemme]

Jack,

Using the ON/OFF switch that should be located directly on your Cobra 400 watt modified sine wave inverter, verify the AM radio squeal interference is really coming from this inverter. If it is, then I would recommend that this inverter be replaced with a pure sine wave type as I am sure that will stop your interference problem.

I guess I don't know what equipment in your Born Free your inverter is setup to power. In may case I installed a 300 watt Samlex Model PST-30S-12A pure sine wave inverter in the cab over entertainment center to power a 45 watt Samsung 20" LCD TV and a 25 watt VCR/DVD player. These two items replaced the original 90 watt 20" Panasonic CRT TV/VCR combo that failed.

I would generally recommend that your inverter's wattage rating be approximately twice the sum of the wattage ratings of all the equipment you intend to power with it to make sure the inverter will handle the initial heavy startup loads some equipment draw.

My inverter was plugged into the 12 VDC cigarette lighter socket that was located next to the 120 VAC power socket for the old TV in the entertainment center. Therefore, I power the new TV and VCR/DVD units all the time via this inverter even though they could be powered from the 120 VAC socket when AC power is available from shore line or the generator. I found out it is just a lot simpler to let the inverter power these two units at all times whether plugged into shore line power or whether the generator is running.

If of interest, I purchased my 300 watt Samlex inverter for $169 from DonRowe.com available at the following website link: http://www.donrowe.com/inverters/puresine_300.html

If a 300 watt inverter is not enough power for your purposes, Samlex also makes a 600 watt unit that can be purchased from DonRowe.com for $246 and available at the following website link: http://www.donrowe.com/inverters/puresine_600.html However, an inverter of this power rating should be wired directly to your coach batteries with heavy cables and not connected to 12 VDC power via a Born Free cigarette lighter socket which is fused for only 15 amps (and that is for all such sockets in the coach which are wired in parallel and connected to that single 15 amp fuse). Remember that a 600 watt inverter fully loaded will draw more than 50 amps from its source of 12 VDC power.

My 300 watt inverter installation is only called on to supply 70 watts, so it draws only approximately 6 amps from the 12 VDC cigarette lighter socket, well within the 15 amp fused limit. Born Free warns against using those sockets for powering inverters but at this low current draw, using it for that purpose has not been a problem for me.

Also if you want more information about the advantages of pure sine wave type inverters over the modified sine way type (and other info), here is a link to a FAQ on this subject: http://www.donrowe.com/inverters/inverter_faq.html

[lassen]

Bill Hemme....Wanted to thank you for your information and list of sources. Also to let you know that BF has this inverter hard wired to the auxillary DC fuse block located next to the Power Center and fused at 30 amps. This set up is to power the TV / DVD.

Happy Holiday....Jack

[bcope01]

Bill Hemme:

Interesting quote from the DonRowe.com website inverter FAQ section:

The small inverters (400 watts and under) come with a cigarette lighter adapter, and may be plugged into your car's lighter socket (although you will not be able to draw more than 150 to 180 watts from the cigarette lighter socket).

Since your application only requires ~70 watts of power, plugging your 300 watt inverter into the lighter socket is adequate. However, it appears that if you had a need for all 300 watts, you'd need to hard wire the inverter directly to the battery.

Bill

[whemme]

Bill,

I agree completely. If I were to attempt to draw the maximum 300 watts from my 300 watt Samlex inverter, the unit would need to draw approximately 27.5 amps (assuming a 90% efficiency). And that would certainly blow the 15 amp fuse in the Born Free power distribution panel. My BF 26' RSB coach is equipped with three of the 12 VDC cigarette lighter power sockets, one in the cab over entertainment center, one in the wardrobe cabinet on the inside wall forward of the refrigerator, and one on the rear wall behind the refrigerator in the rear bed area.

Born Free posted a decal near all three of these outlets warning against using them to power an inverter. Again, I chose to do it anyway because my current draw is small at only 6 amps.

Actually I also have a small 50 watt inverter plugged into the wardrobe cabinet socket that I use to recharge my electric shaver and my cell phone when needed. Even though this power comes off of the same 15 amp fuse, I doubt whether this inverter draws more than 0.5 amps in this kind of charging duty. I have equipped my Samlex inverter in the entertainment center with a 3 way AC outlet jack - one for the LCD TV, one for the VCR/DVD player, and one to run my laptop computer from. Again, I am guessing that the laptop causes approximately a 1.5 amp current draw from the 12 VDC source.

Looks like I may be drawing at total of 8 amps for my two inverters assuming that I have everything that I listed above plugged in and turned on.

[rjcorazza]

My 95 BF may have had the 12v system changed, but on mine the engine alternator DOES charge the coach batteries regardless of the position of the battery switch. The battery switch only isolates the coach batteries from the converter and coach loads.

I will eventually use the well switch by the driver to interupt the alternator cables to the coach batteries, and add a 3 way battery switch inside the coach to isolate the coach batteries from the converter / coach loads.