I recently purchased a Barth mobile medical lab and I am converting it into a coach. Can anyone direct me to a switch that turns the system from electrical to 12 volts. Is it an automatic system?
Thanks

I too have a former mobile medical lab. What switch are you talking about? I use 12v and 120v at the same time.

The only connect/disconnect switches that I have is located in the bottom of the waiting room closet...

gen 1/off/gen 2 selector switch on the left.

shore/off/generator selector switch on the right.

These 2 switches, in the top part of this picture, control all of my 120v electrical supply between the generators and shore power.



Here is what the control panel looks like for both generators and the fresh water/waste tank info center.

˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„
	1990 Barth Regis Widebody 8908 0128 40RDS-C1 L-10 Cummins Allison MT647 Transmission Spartan Chassis		1991 Medical Lab Conversion 9102 3709 33S-12 Ford 460 MPFI C6 Transmission Oshkosh Chassis
Quick Link: Members Only Link To Send Me A Private Message

Bill, Thanks for getting back with me.
I dont have the control panel generator / disconect swiches like yours.

There must be a reset button that I cannot find.
I serched the site and there is some discussion regarding the charging system from the converter box. I suspect this is where the problem is. The 12 Volt system will chagre and operates after the coach driven but not while attached to shore power.

I checked out your restoration. Nice work. I am considering a refrigerator that is electric only. Is that what you have done and are you ok with it?

Thanks
Chris

quote:

Originally posted by Chris Tyler Texas:
I checked out your restoration. Nice work. I am considering a refrigerator that is electric only. Is that what you have done and are you ok with it?

Thank you for the compliment and welcome to our forums.

My refrigerator is indeed a household unit. If you are off the grid alot then you'll need an RV fridge or you'll be running the generator alot. I've had a household fridge since 2004 and I haven't had a problem yet.

If I am on the road for an extended period I'll fire off the generator while driving to keep the fridge cool.

If you are plugged in to an outlet all of the time, then the lack of a propane/12v fridge is not really a problem.

Talk about a poorly stocked refrigerator
WHERE'S THE BEER?

Nick

You know, as soon as I took that picture I figured someone would analyze the contents instead...

Beer in a fridge ??? Maybe as a pre-cooler for the ice chest!!! I use a large ice chest for my beer. A fridge doesn't get them cold enough for me!!!

Most of my normal stuff was back in the house. Right after I took this shot I unloaded the rest of this stuff from the fridge.

Bill, a little quick noodling puts your fridge well into the inverter world. I have done this for mine and it works quite well. The 1.65 amps shown on the sticker will require 17 to 18 from a battery through the inverter. I am guessing the on cycle time is about 1/3 so you may need 6 or 7 amps per hour with the door closed. Figuring a maximum discharge of 40% for the battery and at least a 100 amp hour capacity you should get around 7 hours out of the charge. With two house batteries there should be plenty for quiet time. If you are traveling there would be no drain until boondocking or hooking up. Most inverters will drop out around 11.3 volts which is also helpful for battery life.
The downside? Less exercise for the genny.

Beer, wine or Nicks favorite. Anyone ever check what the law is , in regard to beer and the like in a Barth under way. can you have an open bottle of wine in the fridg???

As we are planning the supplies
for the fabulous Michigan GTG on June 25 to 29. All who wander are not lost. Got to love the art in Barth

quote:

Originally posted by ccctimtation:
Bill, a little quick noodling puts your fridge well into the inverter world. I have done this for mine and it works quite well. The 1.65 amps shown on the sticker will require 17 to 18 from a battery through the inverter. I am guessing the on cycle time is about 1/3 so you may need 6 or 7 amps per hour with the door closed. Figuring a maximum discharge of 40% for the battery and at least a 100 amp hour capacity you should get around 7 hours out of the charge. With two house batteries there should be plenty for quiet time. If you are traveling there would be no drain until boondocking or hooking up.

Looking for an informed recommendation then. I would rather be oversized than undersized.

My thoughts were to rip out the spare genny and hook up the electrical wires to the switch marked Gen 1. I'll relabel it to read Inverter. My generator is 7k 50a. I would need to be careful not to leave my roof a/c units on if I do hook it up that way.

The other thought would be to use it for the fridge and computer only. But I like the idea of a whole house unit.



Here is my setup - there are 2 4D Interstate batteries hooked in parallel for the house. I have a group 31 for the starting circuit.



Here is the spec sheet on the D4 Battery.



Yes I know, it is an obscene amount of Batteries for a coach without an inverter. In the winter or late fall these are sold off to one of many construction contractors who are trying to fire up their dozer for snow/parking lot cleanup work. I've never had these longer than 6 months... and I can't sell just one as most of the times they are sold in a set for 24v.

No, I do not sell them as new, I sell them as used. Basically, I get what I paid for them instead of what they list for. Free Power for me, discount for the contractor. Win-win for all as they were never run down or are that old.

At this point it is a 24+ month warranty instead of a 30 month warranty. I punch my date plugs before I put them in my own equipment.

And if one year they don't sell, oh well. I then own them for myself.

Hrs. at Ampere Load
5amp 38.0hr. 15amp 11.5hr. 25amp 6.5 hr.

4DM SRM-4D
From the website the ampload shows lotsa capacity particularly at the fridge only load of 6.5amps. I think you could put in a large Pro-sine with charger http://www.xantrex.com/web/id/41/p/1/pt/8/product.asp
The neat thing about these is that you get a real sinewave rather than the modified sine that I have. Makes electronics a bit happier, probably any lamps with CFLs also. You hook this up to the loads you want and the unit does a pass through when you go off line. This is so transparent that the clock on the microwave stays on when switching off shore. When you go back to shore or genny the inverter holds on for a minute or so before unlatching to 110.
Think, inverter has shore/genny inlet for 110, supply from it to distribution panel loads selected (fridge, microwave, two or three or? selected outlets). Power goes off inverter takes over the output to selected outlets. Power comes on inverter reverts to multi-stage charger.
Major caution, do not load system greater than alternator output without making sure you shed some of the house system load. I am not certain of all possible consequences but I can think of ones less than desireable. Good application for your second interruption switch.
Be happy to discuss if you want to call. All above worth what you paid.
Tim

quote:

Originally posted by ccctimtation:
All above worth what you paid.

I've looked at the ProSine 2.0 in the past and have thought about that unit. I see how it is hardwired to separate circuits and how it does an automatic transfer with line voltage sensing.

These are pretty expensive units ranging in price from around $1,800-$1,100.

Thoughts?

I still want to remove the extra generator and install a larger storage compartment in its place.

Why would I need a second generator anyway... especially with a 2000w inverter?

NOTE: Normally I would remove this and make up a separate post so I don't step on another post... but this line of thought, questions & answers, I believe, is directly related to what Chris Tyler Texas may want to pursue for himself seeing that he is contemplating doing the same type of thing.

quote:

Originally posted by Bill N.Y.:

quote:

Originally posted by ccctimtation:
All above worth what you paid.

I've looked at the ProSine 2.0 in the past and have thought about that unit. I see how it is hardwired to separate circuits and how it does an automatic transfer with line voltage sensing.

These are pretty expensive units ranging in price from around $1,800-$1,100.

Thoughts?

I thought enough of the Prosine line to buy a 2500. I particularly like its ability to charge a lot in a short time. Not installed yet, though.

quote:

I still want to remove the extra generator and install a larger storage compartment in its place.

Why would I need a second generator anyway... especially with a 2000w inverter?

Only a commercial or medical user. I can't imagine an RVer needing more than one genset. Our 7K is big enough to run both ACs at once, but we are fine with just one running. We close off the bedroom on really hot days, anyway, to avoid all that window heat, so one AC does it. For our purposes, a genset need be only large enough to run the microwave, toaster oven, or one AC.

If I were starting over, I would install a Honda or Yamaha 2800 or 3000 inverter on a slide mount.

quote:

Originally posted by ccctimtation:
Bill, a little quick noodling puts your fridge well into the inverter world. I have done this for mine and it works quite well. The 1.65 amps shown on the sticker will require 17 to 18 from a battery through the inverter. I am guessing the on cycle time is about 1/3 so you may need 6 or 7 amps per hour with the door closed. Figuring a maximum discharge of 40% for the battery and at least a 100 amp hour capacity you should get around 7 hours out of the charge. With two house batteries there should be plenty for quiet time. Most inverters will drop out around 11.3 volts...

I installed an 1800 watt inverter and left it to power my 120v fridge. After 27 hours, 65-85 degree range, open and close the fridge 12+ times, turned off the inverter for 1/2 an hour, my batteries are now at 12.46 volts which places it at the "80 percentage of charge" range.

I checked the Interstate Battery Website and it states "To get the most charge-discharge cycles out of a deep-cycle battery, it should not be frequently discharged below a specific gravity of 1.190 as measured by a battery hydrometer."

That 1.190 specific gravity places the Battery voltage at 12.20 volts or at the "50 percentage of charge" range.

Question: Fill in the blank.
I think that I'll kick on my charger at the "___ percentage of charge" range.
My answer is 65 or 12.32v

Yes-No... What would you do? Thoughts?

I know that this is Bill H's favorite topics. .



I'll tell you... I'm like a kid in the candy store with this inverter. I should have done this awhile ago!

Problem is that in order to use the battery voltage as a reference for discharge, all load has to be removed for some minutes and allow the voltage to settle, then what ever you read is an "indication" of the state of charge.


Example: Morning battery voltage-12.5 VDC, when I kick on my coffee maker in the morning, the battery voltage will drop to 12.0 VDC and by the time the coffee is made the battery voltage is at 11.8 VDC. As soon as the coffee maker heater clicks off the battery voltage will go back up to about 12.3 VDC and slowly rise back to 12.3-12.4 VDC. I don't worry about charging the batteries until later in the day.

Gel or AGM batteries are a completely different story.

quote:

Originally posted by MWrench:
Problem is that in order to use the battery voltage as a reference for discharge, all load has to be removed for some minutes and allow the voltage to settle, then what ever you read is an "indication" of the state of charge.

Sorry Ed, I should have stated - turn off inverter 1/2 hr and then checked voltage readings. I'll reword my post.

You have to admit... for most people, it is alot easier to check the voltage than it is to whip out the trusty hydrometer.