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Electrical relations

Recently I posted a couple of threads, one dealing with my charger/inverter and the second on my salesmen sw. After camping this weekend at Lazy Days I cant help but think maybe they are related. Let me explain, first the salesman sw.  Works fine when plugged into shore power or when the engine is running. When unplugged and engine not running does not work. When engine is running I can start the generator and when its plugged in but when unplugged and engine not running it will not start. Also when engine is running I can start the generator but when I shut the engine off the generator shuts off. Now the charger/ inverter. When the engine is running it puts out 14 volts. When plugged in I'm getting 17 volts. And finally all these problems came at once which makes me think they are related. Now I need opinions which I greatly appreciate. 

Re: Electrical relations

Reply #1 –
A bad cell in the house battery can do all that.

Fully charge them then load test them or if wet cell, check each sell with a hydrometer.

Re: Electrical relations

Reply #2 –
This COULD explain it all...

Salesman switch does not MAKE electricity, it just connects house battery bank to coach for lights, gen start, water pump, etc.  When switch is off nothing will be powered.  When switch is on, IF battery is completely dead / empty, nothing will work.

IF house batteries are dead / empty and damaged it is the same as if they are not in the coach.

When switch is on and engine is running, alternator generates electricity that flows though the isolator to power all coach things.  When engine is turned off, nothing will work.

When plugged into shore power the inverter/charger will generate electricity that powers all coach things.  When shore power is disconnected, nothing will work

As to the voltage from charging sources:

Alternator has about correct voltage which means it is working ok and likely will not damage any electronics or working batteries.

Battery charger at 17 volts is incorrect and way too high and left alone for a long time, would likely damage house batteries, and start battery bank if connected to house bank. 

17 volts could come from charger being at an equalize setting, but likely is from a failed charger.  While we don't know why charger is putting out 17 volts, you do have a possible answer to your symptoms so well described.

If you have multiple house batteries, try to run with just one battery at a time.

Try to use a stand alone battery charger connected to house batteries.

Try to temporarily use just a different battery in place of house batteries, but be aware 17 volts if still coming out of charger, will damage a new battery.  So maybe better to install a different battery (any size, from car or start bank) and a stand alone charger.

Good luck.




Re: Electrical relations

Reply #3 –
Joe, if you can get a meter to the output of the charger you might have your answer.

Re: Electrical relations

Reply #4 –
Sounds as if there is NO connection to the house batteries. The alternator or the inverter/charger is supplying all the 12Vdc.
The charger with no load connected could read high voltage especially if reading with a very high impedance meter.
Agree with the above statement....... sounds like a problem with the house batteries or connection between them and the salesman switch.
Just a thought...........

Re: Electrical relations

Reply #5 –
Quote from: Barry & Cindy –
This COULD explain it all...

Salesman switch does not MAKE electricity, it just connects house battery bank to coach for lights, gen start, water pump, etc.  When switch is off nothing will be powered.  When switch is on, IF battery is completely dead / empty, nothing will work.

IF house batteries are dead / empty and damaged it is the same as if they are not in the coach.

When switch is on and engine is running, alternator generates electricity that flows though the isolator to power all coach things.  When engine is turned off, nothing will work.

When plugged into shore power the inverter/charger will generate electricity that powers all coach things.  When shore power is disconnected, nothing will work

As to the voltage from charging sources:

Alternator has about correct voltage which means it is working ok and likely will not damage any electronics or working batteries.

Battery charger at 17 volts is incorrect and way too high and left alone for a long time, would likely damage house batteries, and start battery bank if connected to house bank. 

17 volts could come from charger being at an equalize setting, but likely is from a failed charger.  While we don't know why charger is putting out 17 volts, you do have a possible answer to your symptoms so well described.

If you have multiple house batteries, try to run with just one battery at a time.

Try to use a stand alone battery charger connected to house batteries.

Try to temporarily use just a different battery in place of house batteries, but be aware 17 volts if still coming out of charger, will damage a new battery.  So maybe better to install a different battery (any size, from car or start bank) and a stand alone charger.

Good luck.
B/C, agree with you, basically what we told Joe last week, he needs to get decent charger and check batteries before he does anything else. Are you sure about gen start going through salesman switch? Your mod? Have not seen it on my coaches, gen start is always dedicated line to coach batteries.

Re: Electrical relations

Reply #6 –
Jim, I was generalizing about the salesman switch, and you are correct that it does not power the genset.

Actually years ago, we removed our salesman switch which was mounted on rear-side of step.  We learned that the two large salesman switch cables are both sourced on the top of the 12-volt bay-wall breaker panel behind the big large white cover.  We disconnected both cables at the breaker panel and put a short jumper across the connections.

We wanted to cut a large hole on step wall for access to the air fitting on the air bag located on the other side of the step wall and found the heavy duty cables and switch were in the way, and with the disconnected switch, we had a clear shot at the air bag.  We were changing all 8 air bags and the two front bags were easier to change with our access holes.

Over the last 20 years, we never used our salesman switch and figured we would later put it back in action on the bay wall connection.  Also figured there must be some voltage drop on the pair of very long cables, so removing approx. 40 feet of cable, replacing it with 4 inches could benefit us.

A month ago, we put the salesman switch on the main ground house battery to fully disconnect the battery bank when storing our motorhome.

Re: Electrical relations

Reply #7 –
Quote from: Barry & Cindy –
Jim, I was generalizing about the salesman switch, and you are correct that it does not power the genset.

Actually years ago, we removed our salesman switch which was mounted on rear-side of step.  We learned that the two large salesman switch cables are both sourced on the top of the 12-volt bay-wall breaker panel behind the big large white cover.  We disconnected both cables at the breaker panel and put a short jumper across the connections.

We wanted to cut a large hole on step wall for access to the air fitting on the air bag located on the other side of the step wall and found the heavy duty cables and switch were in the way, and with the disconnected switch, we had a clear shot at the air bag.  We were changing all 8 air bags and the two front bags were easier to change with our access holes.

Over the last 20 years, we never used our salesman switch and figured we would later put it back in action on the bay wall connection.  Also figured there must be some voltage drop on the pair of very long cables, so removing approx. 40 feet of cable, replacing it with 4 inches could benefit us.

A month ago, we put the salesman switch on the main ground house battery to fully disconnect the battery bank when storing our motorhome.
Good Idea, have never use mine, but thinking about voltage drop and resistance, best to to put it next to batteries. Thanks for the tip.

Re: Electrical relations

Reply #8 –
Before taking out the 12V cutoff at the steps, you might see what actually runs thru that 90 amp breaker.  For instance my solar, as most are, is wired directly to the house battery, not thru the 12V panel in the bay.  I like being able to leave for a few hours, easily cutting off most of the 12V draw, and not having to run around the rv making sure all the 12V is off, ceiling fans, water pump, closet light, bathroom light, etc.  I also have a ground cutoff off on both chassis and house batteries for when I'm away longer and wish to cut everything on that bank off.

Re: Electrical relations

Reply #9 –
Quote from: Jack Lewis –
Before taking out the 12V cutoff at the steps, you might see what actually runs thru that 90 amp breaker.  For instance my solar, as most are, is wired directly to the house battery, not thru the 12V panel in the bay.  I like being able to leave for a few hours, easily cutting off most of the 12V draw, and not having to run around the rv making sure all the 12V is off, ceiling fans, water pump, closet light, bathroom light, etc.  I also have a ground cutoff off on both chassis and house batteries for when I'm away longer and wish to cut everything on that bank off.
Thanks Jack, but I have the PMC Intellitec system with a several control buttons around coach that basically turn off all 12 volt loads [except water pump]. I would keep the breaker, just remove the switch and its wiring.

Re: Electrical relations

Reply #10 –
Quote from: jcus –
Thanks Jack, but I have the PMC Intellitec system with a several control buttons around coach that basically turn off all 12 volt loads [except water pump]. I would keep the breaker, just remove the switch and its wiring.
Jim,
It's curious that your 2003 does not have the water pump on your Intellitec switch panels. 
Several of my switch panels (and I've seen other 2002 U320's.....but they may have been customized) have the water pump and water fill valve circuits on the appropriate (kitchen, bath, utility bay, front door) Intellitec stations. 

Of course, having an Intellitec station by the entry door makes things even more convenient. For those that don't have an Intelletec System, when leaving the coach for short periods of time, just one (three second) "Master Lights Off" button press and ALL (30) of the Intellitec circuits, power down. The 12 Vdc is removed from all circuits until you once again "press the button for an instant"  for an individual circuit, as needed.

We also have the salesman switch, but when in public spaces such as restaurants, we can leave a few manual lights on, making the coach appear occupied, but power down the Intellitec, which minimizes battery drain and risk of water where it isn't wanted.

Our coach has ten of these Intellitec stations, varying with the circuits pertaining to each particular area, or able to switch lots of lights on and off from the underside of the cabinets over the bed.  DW detests the scheme because she has to read the switches.  I love it because I just push from memory, but also fear it because the stations communicate over twisted wire pairs with computers that are no longer made.  One day, a single failure will be very expensive.
HTH,
Neal

Re: Electrical relations

Reply #11 –
Neal, I do have the water pump button in 5 places, {wet bay, bathroom, toilet, kitchen and by entry door} but the master 12 volt switches [also labeled master lights off], in the bedroom and by the front door, only turns off 12 volt lighting circuits. May be modified, have not seen another coach of my era with intellitec. I do have intellitec buttons for two 1500 watt aqua-hot heating elements, which I really like because I can run both on 30 amps, [no starting surge like a ac would require]. Will keep coach warm down into the 30's without diesel. Am also dreading the day it starts to cause problems, but have read posts on other forums about an upgrade to current PLC modules, and reprograming available for about 3 grand.

Re: Electrical relations

Reply #12 –
Here is a brief update. Disconnected the charge/inverter and charged batteries and load tested. While showing 12 volts they failed the load test. Have ordered to new 8d gell batteries and will install. I plan to reconnect charger/inverter and measure voltage from charger. If still high i will replace with a new one. Maybe the charger was sending high voltage because batteries were dead.

Re: Electrical relations

Reply #13 –
Quote from: joeszeidel –
Here is a brief update. Disconnected the charge/inverter and charged batteries and load tested. While showing 12 volts they failed the load test. Have ordered to new 8d gell batteries and will install. I plan to reconnect charger/inverter and measure voltage from charger. If still high i will replace with a new one. Maybe the charger was sending high voltage because batteries were dead.
Just remember, anything over about 14.2 volts [max bulk charge voltage for most gel cells] will damage your new batteries.

Re: Electrical relations

Reply #14 –
Quote from: jcus –
Just remember, anything over about 14.2 volts [max bulk charge voltage for most gel cells] will damage your new batteries.

Yup, we've got fresh batteries, here's after dry camping for a few days, then charging. It sits at around 13.4 the rest of the time when hooked up. Our "True Charge 40" indicates full charge @ 13.2/ 13.4

Re: Electrical relations

Reply #15 –
Joe
Check the startup mode of your inverter/charger.
When I purchased my 96 U320, the inverter/charger startup mode had been set to "Equalize" which sent 100 amps to the batteries while tripping the 20 amp breaker in the 120 VAC power panel when the inverter/charger received 120 VAC.
This was set using dip switches in the back of the remote control on the OEM inverter/charger in my 1996 U320.

Equalizing new Gel batteries will quickly damage them.

Re: Electrical relations

Reply #16 –
Wyatt i believe i will have to remove the panel by the 4 screws and pull it out to see the dip switches. Im not changing anything or using different batteries they will be 8d gell batteries which has always been in there.

Re: Electrical relations

Reply #17 –
Well here is current status. Brett, The batteries were dead. Replaced them with AGM 8d from oriellys. Great price $849 including tax and they installed. With that the salesmen switch works and I can start Generator. The voltage at the batteries when engine running 13.3v. Now the bad news. When plugged in I get 17volts. I pulled remote and checked dip switches and equalize was off and it was set for gell batteries. I would like to replace with something easy to install and not expensive. My current model is a Heart 25 charger/inverter. Can it be repaired?  Thanks everyone for your help I learn something new every day.

Re: Electrical relations

Reply #18 –
Reset the dip switches for wet cell and check voltage

Re: Electrical relations

Reply #19 –
And don't scrimp on inverter charger Victron and Magnum good brands to look at, search past posts, a lot of threads on the topic