Screen Removal Bargman L-300 Door Handle brakes Satellite Fuel Tank Fire Extinguishers Roof Antenna Tech Talk Forum Shortcut Motor Oil Window Generators headlights batteries Radiator AC Unit Grab Handle Wiper Blades Wiper Blades Door Locks Door Locks Door Locks Door Locks Rims Front Shocks Rear Shocks Front Tires Oil Filter Steps Roof Vent Awning Propane Tank Mirror Info Clearance Lights Clearance Lights Clearance Lights Clearance Lights Clearance Lights Spartan Chassis Gillig Chassis Freightliner Chassis P-32 Chassis MCC Chassis
    Forums    Tech Talk    12V system gremlin
Go to...
Start A New Topic
Search
Notify
Tools
Reply To This Topic
  
12V system gremlin
 Login now/Join our community
 
Supporting Member of Barthmobile.com 12/12
Picture of Lee
posted
The scenario: 10+ years of perfect service from the 12v system. During recent trip, while using lights/fans/pump, I fired up genny for microwave use - everything was working fine. When I shut down genny, the whole 12v system went down with it - no lights/fans/pump/12v recepts. Fired genny back up and 12v came back online. Tried the same thing with shore power - same results. 12v system works as long as I supply 120v, but won't operate on its own.

Checks so far (performed by admitted electrical illiterate):

1. Coach battery tests 12.7v at rest - battery ground "appears" good.
2. No load transfer switch - just old fashioned either/or plug for genny/shore power.
3. 12v fuse panel shows good fuses - all test OK on both sides of buss (continuity only)
4. Nothing changes when chassis battery brought on line with coach battery
5. When hooked to 120v, PD converter indicates all cycles (charge/float/desulfate) are operating
6. All 120v breakers appear OK & set.
7. Cursory look at under belly wiring - no breaks/abrasions/disconnections observed

Summary: I'm stumped - Any thoughts & suggestions appreciated Click
 
Posts: 1266 | Location: Frederick, Maryland | Member Since: 09-12-2003Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Doorman
posted Hide Post
Lee, I think your problem is in your converter. When running off 120v the converter supplys your 12v. I think the relay to connect back to the battery circuit must not be making contact.

Check 12v from batteries to converter, then 12v from converter to 12v fuse panel. This is the way my 76 is wired. My 86 does not use a transfer relay.


1986 31' Regal -1976 Class C
454/T400 P30 -350/T400 G30
twin cntr beds - 21' rear bath
 
Posts: 1026 | Location: Dayton, Ohio | Member Since: 09-27-2009Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Doorman
posted Hide Post
After looking at PD website. The 12v does not transfer thru their unit. I would look for a open between batteries and PD converter. Does your 12v to your converter come from your gen. lugs? Is there a breaker in line there?


1986 31' Regal -1976 Class C
454/T400 P30 -350/T400 G30
twin cntr beds - 21' rear bath
 
Posts: 1026 | Location: Dayton, Ohio | Member Since: 09-27-2009Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 2/16
Captain Doom
Picture of Rusty
posted Hide Post
Older converters are dual-output. When 120VAC is present, a relay powers the 12VDC direct from the converter. When 120VAC isn't connected, the relay switches to the battery.

I suspect the converter also.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
 
Posts: 7734 | Location: Brooker, FL, USA | Member Since: 09-08-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 12/12
Picture of Lee
posted Hide Post
Yep, it was the converter alright.....Replaced
and back in business. 6 years on a new PD9245....I woulda thought more lifespan than that.......My genny might have spiked to cause
the problem, but PD claims the unit protects itself from that....Oh well....Thanks for the advice guys....On the road again.... Thumbs Up
 
Posts: 1266 | Location: Frederick, Maryland | Member Since: 09-12-2003Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 2/16
Captain Doom
Picture of Rusty
posted Hide Post
I would guess there's more to it than that. The 92xx series is single-output, that is 12VDC always comes from the batteries and the converter when plugged in (the converter basically acts as a battery charger). The batteries are always connected unless the 12VDC master is off.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
 
Posts: 7734 | Location: Brooker, FL, USA | Member Since: 09-08-2005Reply With QuoteReport This Post
  Powered by Social Strata  
 

    Forums    Tech Talk    12V system gremlin

This website is dedicated to the Barth Custom Coach, their owners and those who admire this American made, quality crafted, motor coach.
We are committed to the history, preservation and restoration of the Barth Custom Coach.