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alternator charging coach batteries

Yahoo Message Number: 66283
Between destinations I boondocked overnight house batteries went from green to red on telltale panel within hours, next morning checked both sets of batteries while engine was warming up-found chassis bat. charging, house bat. not charging. Don't have wiring dia. Any help appreciated.

Bill 04 Inspire 51166

Re: alternator charging coach batteries

Reply #1 –
Yahoo Message Number: 66285
Bill, The symptom suggests the battery boost solenoid, located above the chassis battery on the front wall of the compartment. On the attached diagram, it is in the upper left corner.
The solenoid closes with a signal from either the chassis boost switch (on the driver's side console) or the oil pressure switch (on the engine).
With the engine off, press the chassis boost switch and listen for the solenoid (if you're like me, that means have your wife listen!). Mash it a few times - the solenoid might have been stuck. If there's no "click" the problem is with the solenoid (or the connections - check and clean).
If the solenoid clicked, start the engine and see if you're charging. If not, have your wife hold the switch (engine running). You should see charging voltage on the house batteries. If holding the switch closes the solenoid, the problem is with the oil pressure switch.
You can work around the solenoid with a simple jumper cable. Let us know if you need to go to that step.
For what it's worth, I recently had my oil pressure switch "fail", and was about to buy a new one (from Kevin Waite) when it fixed itself. I never knew if is was a bad electrical connection or a balky switch. But while it was "failed", I just jumped the solenoid after startup each day.
(You didn't mention - - does the house bank charge from the generator/charger?)

Jay

05 Inspire 51457

Re: alternator charging coach batteries

Reply #2 –
Yahoo Message Number: 66296
Quote from: bllmayhew"

Between destinations I boondocked overnight house batteries went from green to red on telltale panel within hours, next morning checked both sets of batteries while engine was warming up-found chassis bat. charging, house bat. not charging. Don't have wiring dia. Any help appreciated. Bill 04 Inspire 51166
you may also want to check if you have an "ACR" installed between the chassis and house batteries -- my 2009 intrigue has one and the 60 amp fuse/breaker was tripped and I could not get the house batteries to charge from the engine despite a fully functional boost switch/solenoid.

Re: alternator charging coach batteries

Reply #3 –
Yahoo Message Number: 66339
Quote from: bllmayhew"

Between destinations I boondocked overnight house batteries went from green to red on telltale panel within hours, next morning checked both sets of batteries while engine was warming up-found chassis bat. charging, house bat. not charging. Don't have wiring dia. Any help appreciated. Bill 04 Inspire 51166
Bill;I had the same problem on my 02 intrigue#11436.replaced the oil pressure sending unit and all is well. Contact me via email or cell 815 222-0728 and I will walk you thru it.
Jim 02 intrigue 11436

Re: alternator charging coach batteries

Reply #4 –
Yahoo Message Number: 66343
This really intrigues me! I would really like to know how changing the oil pressure sending unit can fix the charging problem ?

Ron Baran 09 Magna 7025

Re: alternator charging coach batteries

Reply #5 –
Yahoo Message Number: 66344
It's not the oil pressure sending unit. It is a oil pressure switch.(2 lbs. on mine) When closed it completes a ground circuit that closes the battery boost solenoid so both batteries (chassis and domestic) can charge off of the alternator when the engine is running.
Kevin Burns

00 Affinity 5865

Re: alternator charging coach batteries

Reply #6 –
Yahoo Message Number: 66345
In order to understand how an oil pressure sending unit (I think the original author meant switch) can effect battery charging you need to think about the relationship between your house and coach battery banks and how they are kept charged when the main engine is running as opposed to when on shore power or with the generator running.

Normally the two battery banks are not connected or possibly connected by means of an isolator to allow current to flow to the coach bank from the house bank but not the reverse. This to assure that the coach bank is not depleted by use of house accessories when parked which might make it impossible to start the main engine.

There is, however, the desirability to charge both banks from the alternator when the main engine is running. To accomplish this a solenoid switch operated by a remote manual switch could have been designed into the system so that after the engine is started you could connect both banks for charging from the alternator. In fact there is such a switch labeled "battery boost" which allows the operator to override the normally unconnected banks if for some reason the coach starting bank isn't up to the task and, hopefully, the house batteries still have juice. The engineers in their wisdom and desire to confuse us all and make everything automatic also supplied another switch to activate this solenoid connecting the two banks and this is activated automatically when the oil pressure builds up sufficiently to trip the switch and activate the solenoid switch that connects the two banks and allows the alternator to charge both banks when the main engine is running.

This, of course, creates a number of places where failure can occur, the oil pressure switch, the solenoid switch that actually connects the two banks probably located in the battery compartment to minimize the connection distance, or the alternator or related drive mechanism (belt + belt tension pulley). Unfortunately, when you have a situation where one bank isn't charging it's not obvious where the problem is although there may be clues.

One clue is that with a failed alternator you are able to get a normal voltage reading and charge both banks while going down the road by running your generator set and battery charger incorporated in your inverter. I think under such circumstance the oil pressure switch has to be functional for your coach DC meter to indicate proper voltage which corresponds to the charging cycles of the inverter/charger. Otherwise the coach batteries would charge but the house batteries would only be dependent on the "echo charger" which has a lower voltage output.

I'm just guessing at the mechanism described since I've never seen the workings of our charging system and battery banks in our manuals.

Jim M

'02 Intrigue#11410, ISL 400.

Re: alternator charging coach batteries

Reply #7 –
Yahoo Message Number: 66369
I guess you learn something every day, and that is the benefit of this forum. If the pressure switch does not MAKE, then the theory is that the engine isn't running and therefore you would have no charging. I didn't check the year of the coach involved, but I would think the newer coaches with all the electronics would not have this problem.

Ron Baran 09 Magna 7025

Re: alternator charging coach batteries

Reply #8 –
Yahoo Message Number: 66374
Ron,

I don't think you still have figured it out. The purpose of the switch is to disconnect the chassis batteries from the domestic batteries when the engine is not running so that you don't end up stranded somewhere. Just because the key is on doesn't mean the alternator is spinning. If it doesn't have oil pressure you better hope it's not spinning. At least that's my "theory". Your response is so condescending it irritates the ___ out of me.
Kevin Burns

00 Affinity 5865, Old outdated POS

Re: alternator charging coach batteries

Reply #9 –
Yahoo Message Number: 66375
Kevin Not sure what you find condescending. In fact, I said the same thing, as your explanation---there has to be oil pressure before the connection is made. I thought it was a compliment that you can learn something on this forum every day. Lighten up man!!

Ron Baran 09 Magna 7025

Re: alternator charging coach batteries

Reply #10 –
Yahoo Message Number: 66376
"Otherwise the coach batteries would charge but the house batteries would only be dependent on the "echo charger" which has a lower voltage output."

Jim M,

Good post, but wouldn't the Echo Charger be charging the coach batteries while the gen is running instead of the house batteries?

Tom

Trans-Specialists/Lifeline Batteries
01 Magna 5999

Re: alternator charging coach batteries

Reply #11 –
Yahoo Message Number: 66382
Ron,

My bad. I guess I'll have to quit reading my emails at 1am after a long day when I'm not feeling good. I read my own email this morning and it was a bit nasty. I think I said what I did the way I did because Your comment "I didn't check the year of the coach involved, but I would think the newer coaches with all the electronics would not have this problem." I don't know if they started using another method to disconnect the chassis and domestic batteries from each other( when the engine isn't running) in the newer models but I never saw the design as a "problem". They also use the same oil pressure switch on my coach for the audible "Danger Low Oil Pressure" warning. But my guess is Your newer coach has the same method used in it, maybe not, but I would be interested in knowing how they did it in your newer coach if it is indeed an improved design. But to just automatically assume that because your coach is newer it is better and doesn't have these "problems" seems somewhat condescending.
Kevin

00 Affinity 5865,

Re: alternator charging coach batteries

Reply #12 –
Yahoo Message Number: 66385
The answer to your question is "Yes, if the main engine is not running or the oil pressure switch is not functioning to, in effect, connect the two banks in parallel". The output of the echo charger (at least mine) is so low compared to the alternator or inverter/charger that it's incapable of really charging the coach bank. It's just meant to maintain the coach bank while stored on shore power. As near as I can see there's not place to adjust the voltage on my echo charger. later models may be different.

I don't pretend to be an expert on exactly how they've got these thing hooked up but when the main engine is running and the oil pressure switch (not simply the oil pressure sender) activates the solenoid or relay that connects the two battery banks then, if the generator set is running, the inverter/charger is charging both banks in parallel. The echo charger is there and on but its voltage output is relatively low compared to the inverter/charger or alternator. Your gauge, obviously, reads the highest voltage in the system depending on exactly how it's hooked up. If you have a functional oil pressure switch and run the generator while going down the road you will see that the voltage reading either on your panel DC meter or SilverLeaf monitor will reflect the 3 stage charging cycle voltage of the inverter/charger - not the relatively constant output of the alternator which doesn't have absorption, saturation and float cycles. Incidentally, as I assume most know, the charger part of the inverter is on regardless of whether the inverter is switched on. The only way to turn it off is to trip the inverter circuit breaker. At least that's the case with my unit.

I'm not really sure which is first in line, so to speak, for the charging entities, alternator, inverter/charger or echo charger but it would seem logical to have the system set up so that the alternator, if working, would charge the coach (start) batteries regardless of whether the banks were connected but would only charge the house batteries also it the oil pressure switch is functional, in effect, connecting both banks.

At the moment I have a problem with low DC readings with the main engine running and the generator set off (alternator only charging source) but when the generator is started the voltage jumps to the expected voltage from the inverter/charger and, if run long enough, cycles through the various charging cycles. I'm assuming I have a alternator problem and not an oil pressure switch problem and am due to have it checked during a service appointment in a couple days.

Jim M.

'02 Intrigue #11410, ISL400

Re: alternator charging coach batteries

Reply #13 –
Yahoo Message Number: 66398
Jim: My understanding is that the echo charger only works one way - when the house bank has been charged (I think from any source - gen, shore, solar, etc) it allows current to flow to the chassis battery, thus maintaining a charge in it. It doesn't work the other way, will not try to charge house batteries from the chassis battery.
That job is done through the alternator circuit and as others have stated, it is dependent on having the engine running. The echo charge circuit works with no engine running, obviously.

Richard Owen '05 Inspire 51442

Re: alternator charging coach batteries

Reply #14 –
Yahoo Message Number: 66400
I have experienced low voltage while the engine was running.
A new/rebuilt alternator fixed the problem. however during the install process I learned that the alternator requires a 12 volt source in order to put out the charging current ( no 12 v input, no output).

Bob Wexler
SOB

Re: alternator charging coach batteries

Reply #15 –
Yahoo Message Number: 66403
I don't think the echo charger "knows" when the house battery is charged or has anything to do with the house batteries. I think the echo charger is "on" whenever there is AC current in the AC system, whether that's from the shore cord or the generator set. If you allow the coach start batteries to discharge a little. Check the voltage across the start battery terminals. Plug in shore power. Then recheck the voltage across the start (coach) battery (ies) I think you will find the voltage at whatever the echo charger is set to put out as long as there is AC whether from the shore cord or the generator set.

In any case that's the way mine works. The voltage reading across my start battery terminals is about 12.5VDC with 120VAC from either the shore cord or generator set. If the main engine is running the voltage across the terminals of the start battery and house batteries is identical meaning, of course, they are connected in parallel and that voltage is whatever the DC in the system is - whether from the alternator or inverter/charger.

Jim M. '02 Intrigue#11410, ISL400

Re: alternator charging coach batteries

Reply #16 –
Yahoo Message Number: 66412
Thanks for your insight. I normally store my coach inside hooked up to 240VAC shore power with the inverter "off".When shore power is sensed the charger part of the inverter goes into action and starts its 3 stage charging routine. Starting around 14.4VDC and eventually stabilizing at 13.6VDC float voltage. This is displayed either on the inverter control panel or measured across the house battery terminals.

In the meantime, after it's been stored awhile, the house batteries still are at 13.6VDC float voltage with the indicator light on the inverter panel indicating a "full charge". The start coach battery, however, stabilizes at 12.6 VDC measured at the battery. This is with the green light on the echo charger "on" indicating it is working OK. AS far as I know there is no means for the user to adjust the voltage of the echo charger up to a float level of 13.6VDC which might be desirable and possibly is a feature or later models echo chargers. I check the electrolyte level in all batteries every couple weeks.

This 12.6VDC level is marginal when it comes to starting but is usually enough. In any case the "Battery Boost" feature is available to allow connecting the house batteries in parallel with the coach start battery.

I normally hook up an electronic automotive charger with auto cutoff across the start battery terminals in parallel with the echo charger every few weeks and the day before I anticipate getting the coach out. The output across the start battery terminals is 13.6 VDC when this charger is hooked up.

I believe there have been a few posts on this site where people who have stored their coaches hooked up to shore power for a considerable period have found their start coach batteries without enough juice to start their coach. Perhaps I misunderstood their postings.

I believe what you are referring to in your 1st paragraph below is an isolator installed so as to allow current to flow from the house batteries to the coach (start) battery but not the other way around. I have no idea whether the CC's have such an isolator in the system. In order for the main engine alternator to be able to charge both the coach start battery and the house batteries there has to be a heavy duty switch (200A solenoid) operated by oil pressure or manually (Battery Boost). This, of course, bypasses any isolator in the system so that both battery banks are charged while going down the road and, incidentally, are also charged by the generator set if running via the inverter/charger while going down the road. If you've ever observed your voltmeter while going down the road on a really hot day while running your generator set and roof top AC's you will see the VDC displayed corresponding to the charger output of your inverter.

Jim M.

'02Intrigue#11410, ISL400

Re: alternator charging coach batteries

Reply #17 –
Yahoo Message Number: 66415
The Echo Charger operation is independent from the presence of 120VAC. The EC device has three connections.

red fused to house positive
red fused to chassis positive
black to ground

The device senses voltage on the house battery. If VDC is 12.8 or higher it sends current to the chassis battery. If house VAC is below 12.8 it is idle.
My coach sits outside without power. I have a solar charge system on the roof. My chassis battery is charged every sunny day as the house battery exceeds 12.8 volts.

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298

Re: alternator charging coach batteries

Reply #18 –
Yahoo Message Number: 66417
What is the charge voltage put out by your echo charger across the start battery terminals when the house bank is >12.8 (I assume you meant VDC not VAC)?

In any case that's good to know in trying to understand how the system works. In other words the echo charger is bleeding off current from the house batteries to the coach start batteries when the house batteries exceed 12.8VDC which makes sense. I'm not sure I understand why the voltage it's "bleeding" to the coach start battery is less than whatever the house batteries are at but apparently - at least in the case of my coach - the voltage limit to the coach battery is 12.6VDC instead of the 13.6 VDC float voltage on the house batteries measured at the same time. This might be explained by the echo charger actually being an inefficient isolator allowing current to flow from the house to the coach battery while dropping the VDC from whatever the coach system ( in my case 13.6VDC) is to 12.6VDC.

Jim M.

'02 Intrigue#11410ISL400

Re: alternator charging coach batteries

Reply #19 –
Yahoo Message Number: 66418
Jim, yes I did mean VDC. I just checked the Echo Charge documentation and my memory was wrong about 12.8 VDG as the beginning charge point. It is 13.0 VDC as quotedfrom the manual below.
"When the input voltage is 13.0/25.5 volts DC or higher, echo-charge automatically switches ON. The LED glows a steady green. When the input voltage is lower than 13.0/25.5 volts, the echo-charge automatically switches OFF, and the LED blinks green. The output voltage of echocharge is limited to 14.4/28.8 volts. When it reaches 14.4/28.8 volts, the charge current will decrease, maintaining a float condition. The starter battery will be fully charged without overcharging.
No load current drain on the house bank is less than 50 milli-amps.
If the input voltage is above 14.4 volts (or 28.8), output will be limited to a maximum of 14.4/28.8 volts."

Here is a link to the Xantrex Echo Charge Manual.
http://www.xantrex.com/documents/Accessories/Auxiliary-Battery-Charger/Echo-charge-OwnerGuide(445-0204-01-01).pdf

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298

Re: alternator charging coach batteries

Reply #20 –
Yahoo Message Number: 66419
On mine, the echo charger is connected to both the engine and house battery but it does not charge the house battery. When the house battery reaches a charge of 13 volts, it triggers the the echo charger to begin charging the engine battery. The installation diagram shows the echo charger connected to both engine and house batteries. Here's a link the the echo charger intallation and operational manual which is in the file section on this site:
http://f1.grp.yahoofs.com/v1/cAIETZZYefxvrInZ468KQu8zEtN0QoFby4UATKNLh7u2RF10zw2vpGDFPv0DINAehdjRUJAuHYbpRGC3bpUyT7AAGpY/Digital_echo_charge_Xantrex.pdf
Hope it works. If not, go to the file section on the left of this screen and find the manual there. The diagram is on page 8.
When going down the road, I believe the alternator is charging all batteries.
By the way, my engine battery voltage is always 13+ volts when plugged into shore power. Anything less that 13 volts (12.5?) tells me I may have a problem, which usually means the echo charger fuse is blown.
Larry, 03 Allure 30856

Re: alternator charging coach batteries

Reply #21 –
Yahoo Message Number: 66420
I didn't answer your question about voltage output from the Echo Charge. I don't know what my voltage on the chassis battery is as I have never checked it. I do know that it is fully charged by the way it starts a cold engine. I doubt 12.6. I'll check when I get a chance. No sunshine in the forecast here for the next few days.
I also see that my link to the EC doesn't work. I don't know how to fix it so you can cut and paste if you wish to see the doc.

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298

Re: alternator charging coach batteries

Reply #22 –
Yahoo Message Number: 66421
I'm not sure of the brand echo charger I have but I've heard later model CC's have a better one than the '02 models. In any case mine seems to be limited to about 12.6 VDC measured across the start battery when the coach batteries measure 13.6 float voltage. The echo charge may be faulty but its light is steady green. That link to the echo charger manual will be helpful.
Your description of how it works makes better sense than the way mine appears to be working.

Thanks.

Jim M.

'02 Intrigue#11410 ISL 400

Re: alternator charging coach batteries

Reply #23 –
Yahoo Message Number: 66423
Jim, after thinking about your description of how yours is operating I wonder about the condition of your chassis battery.
The EC is pushing amps to try and bring the voltage of the Chassis battery voltage to equal the house battery. If it can't get there I suspect either a problem with the ECor the chassis battery. With your green led lit I suspect the chassis battery.
I think you have the same Echo Charge in an '02 as I have in an '04. I don't think they have changed much, if at all.

George in Birmingham
'04 Allure 31038
George in Birmingham
2003 Magna 6298

Re: alternator charging coach batteries

Reply #24 –
Yahoo Message Number: 66424
Jim: You will never see much increase in voltage on the chassis battery from the echo charger. It is a "maintaining" device, not a full 3-stage charging method like the inverter/charger offers.
No, they are not adjustable. The unit has the ability to detect when house bank is charging (by measuring voltage) and it will direct a some of that power to the chassis battery if the voltage is high enough. The charge rate is limited to 15 amps. The newer Echo Chargers are the same. And no, I am not referring to an isolator, I am referring to the Echo Charger - it allows power to go only one way so that the house batteries don't ever draw down the starting battery.

Richard Owen '05 Inspire 51442