BAC Forum
General Boards => Technical Support => Topic started by: Larry Azus on November 27, 2018, 10:16:48 PM
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Our RV had been in storage for four months. While in storage we had it plugged into a 50A circuit and charging. When we went to start the RV the chassis batteries were totally dead - however the house batteries were kept charged fine. At the time, we were able to start the RV by holding the Battery Boost - but several weeks later the chassis batteries were dead again after being plugged in for several weeks.
I had always assumed the shore power charging circuit would also keep the chassis batteries charged - but this did not appear to be the case. Should the charger also be charging the chassis batteries while connected to shore power? Not sure if this is a problem with the charging circuit and/or the house batteries. Any suggestions?
On another note - I could start the generator by holding the Battery Boost switch to bridge the house and chassis batteries. However, the generator would stall as soon as I released the boost switch. This happened for the first five minutes or so (I assume until the chasis batteries held some charge). Does the generator require some level of charge on the chassis batteries in order to run?
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You should have a bi-directional electrical device between the chassis and house battery banks that allows a charging current to charge both battery banks. The typical electrical devices are a BIRD System or an ECHO Charger. Do you know which electrical device you have?
Basically, if your coach is plugged in, then the inverter will charge the house battery bank. After it gets to 13+v, then the bi-directional device will allow the charging current to cross-over to the chassis battery bank. Conversely, when traveling, the engine's alternator will charge the chassis battery bank. After it gets to 13+v, then the bi-directional device will allow the charging current to cross-over to the house battery bank. It sounds like your bi-directional electrical device isn't working properly.
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My unit appears to be the BIRD system. Would this be the Battery Isolator Relay that is suspect (https://www.amazon.com/Intellitec-77-90006-120-Battery-Isolator-Relay/dp/B077YR1W55 (https://www.amazon.com/Intellitec-77-90006-120-Battery-Isolator-Relay/dp/B077YR1W55))? I didn't get a chance to make any measurements yet - I'll head over there tomorrow with a meter. What are some good checks to confirm the defective component (and not battery problem)?
Looks relatively easy to replace - anything to be wary of (obviously after disconnecting all power)?
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Larry, at 13.4v your Bidirectional Isolator Relay Delay (BIRD) switches charging to the other battery bank. When on the road, it switches from an alternator-charged chassis bank to begin charging the house bank, and when plugged in it switches from an inverter-charged or generator-charged house bank to begin charging the chassis side.
The BIRD has been known to fail from corroded or loose high resistance connections. But as reported on this Forum recently, the Big Boy solenoid that does the actual circuit switching can fail from corroded internal contacts. When on the road have you noticed whether or not your house batteries arrive fully charged? If not, the Big Boy is suspect. It could also be your Magnum inverter’s charger has failed, but not likely since your house set is getting charged when plugged in... and over time it goes from Bulk Charge to Absorb to Float Charge, right?
Use a voltmeter to see if when plugged in to 110v power and the remote reads Float Charge (at least 13.4 volts on the screen) that both large wire lugs on either side of the Big Boy indicate identical voltage readings. Over your battery tray and between the chassis and coach Main Switches is a gray door behind which are both above mentioned devices, large-amp 12v fuses, and other components. The Big Boy is front and center. The BIRD is mounted on the inside of the door.
Others here have disassembled, cleaned, and reassembled their Big Boy. Search the Forum.
I’ll leave generator commentary to others more familiar with that circuitry, except to say the genset may rely on fully charged chassis bats to stay running, and they aren’t at that point except via the alternator. With a working BIRD/Big Boy, the genset would eventually go from charging the house set to doing the chassis set, thereby then supporting the generator.
Joel
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Now that you mention it, I do recall a few times that the house batteries were not charging while on the road. However after tapping the Battery Boost switch once or twice they would start charging. This sure sounds like the problem you describe.
I'll head over to take the measurements on the Big Boy tomorrow. How to best isolate the problem to the Big Boy or the BIRD? Can I clean the internal contacts or would it need to be replaced?
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Search the Forum here for “Big Boy” and reference useful info. I couldn’t find the photos I’d seen re. cleaning the device, but you may find something on YouTube, if Bill Lampkin or others don’t chime in here to assist. I think Mike Schumack recently did something with his.
Joel
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Larry,
If you don't have approx. equal voltages on the 2 large terminals of the Big Boy (assuming one of the battery banks is at ~13v), check the "solenoid" output voltage at the BIRD. It should be about 3v or so if the BIRD is working. Dis-assembling the Big Boy is fairly easy. Clean up any corrosion and re-assemble. Be sure to inspect the 'O' ring. If you've got corrosion it is probably because the 'O' ring is allowing moisture in. Hitting the Boost Switch causes the big Boy to close, so sometimes that can get it working for a while if you are in a pinch. After hitting the boost switch a few times, check voltages on the large terminal of the Big Boy.
Steve
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Larry,
There is nothing wrong with your generator. It requires at least a partially charged chassis battery for it to operate, and since your chassis batteries were dead, the only way it could operate is for you to hold down it boost switch so that it could run off of the fully charged house batteries. You just need to repair your "BIRD" system and everything will be OK if you have not damaged your chassis batteries by excessively discharging them.
Gerald
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Quick Update: I went to the RV today and made the suggested voltage measurements at the batteries and Big Boy terminals. While plugged in the house batteries had a float charge of >13.4 volts, but the solenoid output terminal on the Big Boy (as well as chassis batteries) were reading low <8 volts. This seemed to confirm that the Big Boy was not operating.
I removed the Big Boy, took it apart and cleaned and burnished all of the internal contacts and reinstalled. After a few minutes, I heard the Big Boy energize and then started charging the chassis batteries. Hopefully the batteries will recover.
I greatly appreciate everyone's help on this (David, Joel, Steve and Gerald) - Many thanks!
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I’m glad it worked out, Larry, and we appreciate your reporting back affirming our suspicions.
Check the chassis set regularly now, especially after drycamps or storage. Unlike deep cycle house batteries, they don’t like being discharged even once. And after dry camping, charge things up using the generator before hitting the highway; it’ll save overheated alternator issues down the road.
Joel
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I had battery issues for years. Basically, with house-battery priority using an echo charger, once those things get a tad weak nothing ever goes to the chassis batteries, and the parasitic draw of the drivetrain computers eventually drains the start batteries to the basement. Since the house batteries are deep cycle and the chassis are not, the house batteries are much more likely to recover from a discharge.
I re-engineered my system to be chassis-battery priority with an amp-l-start in place of the echo charger and an alternator designed to be used with a solid state isolator. Haven't had an issue since.
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I have been following this thread so I decided to do a voltage test. My house batteries read 15.43 volts and my chassis batteries read 14.43 volts. The coach is plugged in to 50 amp service at my home. Are these readings OK?
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Turn off or unplug the shore power, give it 10 or 15 minutes, and re-test the batteries.
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Turn off or unplug the shore power, give it 10 or 15 minutes, and re-test the batteries.
Ok, just did that. Reading on house batteries dropped to 12.67 volts and the chassis down to 12.49 volts. After turning shore power back on house batteries went up to 14.45 volts and the chassis stayed the same at 12.49 volts. Does this seem ok?
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It probably means the follower charger is not passing anything to the chases batteries yet. Prior to your test, the house batteries were high enough for the follower charger to kick in. It will probably take a little while for the house batteries to reach the cutover point again.
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I guess I'm not quite out of the woods yet with regards to my battery issues...
I went to the storage unit yesterday, and the charger indicated "Float Charging: 12.6V / 0A". I measured both battery banks, and the house batteries were at 12.6V and the chassis batteries were at 11.4V.
I toggled the charge button off and on a couple times, and after a few seconds it indicated "Absorb Charging: 13.9V / 48A". I again measured the battery banks and both were at 13.7V and appeared to be charging properly.
I went back today and again the charger indicates "Float Charging: 12.6V / 0A" and the batteries were in similar state as yesterday. I also measured the batteries with the charger off and the voltages remained the same.
Any ideas on this issue? Is this a problem with the "float charge"?
Thanks for your continuing assistance!
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I assume your coach is plugged in and power is getting to your inverter/charger.
The following is what I see on our coach.
1. When unplugged and generator off, and Cat C-12 not running - if the batteries are fully charged up, then both battery banks will show 12.6-12.7v on the Aladdin.
2. While on the road traveling, (obviously unplugged) and generator off and Cat C-12 running at 1,500 RPMs +/- - both battery banks will show 14.2v +- on the Aladdin.
3. When plugged in or generator on, and Cat C-12 not running - if the inverter/charger is in BULK charge mode, then both battery banks will show 14.2v +- on the Alladin. If the inverter/charger has moved through BULK and ABSORPTION modes to FLOAT mode, then both battery banks will show 13.7v.
I don't understand why your battery banks are not showing 13.7v +- in the inverter's FLOAT mode when your coach is plugged in after the batteries have received a full charge. It sounds like your inverter/charger is doing its job to charge up the batteries, but then quits and doesn't maintain the full charge in FLOAT mode. You cleaned the Big Boy and it appears to be functioning properly. Could the BIRD module be the problem or perhaps your inverter/charger is not getting to and remaining in FLOAT mode?
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Larry,
If you haven't already done so, suggest you check the inverter/charger settings. Also, you may want to try resetting the inverter/charger. Most have a reset button on the inverter.
Steve
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I think you need to take your start batteries to a battery vendor and have them load tested. I think your batteries were damaged when they were so deeply discharged and they are not going to recover. I know that isn't what you want to hear, but that is my opinion.
Good luck, Sam
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Larry,
Your float charge voltage seems low (12.6). I assume that you have a Magnum Inverter/Charger. If so, you should have a battery temp sensor on the house battery bank. If the temp sensor is bad it will adversely affect the Magnum Inverter/Charger (i.e. low float charge voltage). You can check the battery temp at the remote, press the ‘Tech’ button and select ‘Get Temperatures’. Currently, with shore power, ours is in ‘Float’ @ 13.8 volts and battery temp of 8 Celsius.
**Edit**
Also, if your float (house battery) voltage drops below 12.8 volts the BIRD system will cause the Big Boy to drop out and your chassis batteries will not be charged.
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I checked the various Inverter/Charger settings. All seemed to be good - with the exception of the Battery Temperature Sensor (BTS) which was reading 151C. I saw what appeared to be the battery sensor which was hanging freely from the top of the battery bay (in fact, it couldn't even reach the batteries).
Even if I unplugged the BTS cable from the inverter, it still read 151C. I also reset the inverter using the pushbutton on the inverter and still got 151C for the Battery Temp.
It appears that the inverter may be bad - I'll check with Magnum to see if they have any ideas...
Thanks for everyone's help!
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From what you just posted I would suggest that the BTS is bad! At the very least it should be connected to one of the battery posts (I forget which one, I think neg.) That is a common failure item that causes all kinds of weird symptoms as described by folks on all the RV forums.
Good luck
Jerry
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When I unplugged the BTS from the inverter - the reading still displayed 151C. I guess my question would be - what should the "Battery Temperature" reading on the inverter be without a sensor plugged into the inverter?
If the inverter should show 151C without a sensor then it is likely a bad sensor. But if it should display something else then maybe there's a problem with the inverter...? I thought the charger should work without the BTS, but that you would lose that temperature protection (I may be wrong on this, though). The manual seems to indicate that it is optional - but recommended...
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Larry, right now it's 38 outside and my BTS is reading 58 degrees. Batteries are float charging at 13.7 VDC. If your inverter is good it should charge with fewer crazy symptoms without the bad BTS plugged into the inverter.
Jerry
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Larry,
The reading with the BTS disconnected should be 25C, this would allow non-battery temperature compensated charging. It is also my understanding that the BTS is optional but recommended.
Also, I believe that are two types of BTS, one that is connected to the negative terminal of the battery and one that is installed on, or in close proximity to the battery bank. Ours is connected to the battery.
This is from a Magnum manual.
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If the BTS is installed, the charge voltage settings will increase if the temperature around the BTS is below 77°F (25° C), and will decrease if the temperature around the BTS is higher than 77° F (25° C).
The inverter/charger will shut down if the Battery Temperature Sensor (BTS) has reached a temperature greater than 54°C/129°F.
Remove the BTS from the inverter BTS port. If the BTS reading goes to 25°C/77°F, replace the BTS. If the reading does not go to 25°C/77°F, then inspect the BTS port for cleanliness and/or have the inverter/charger serviced.
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Larry, As others have suggested, reboot your inverter. Unplug from shore power, open the gen breaker, turn off the inverter using the small on-off switch on the inverter itself, then open both the chassis and house battery disconnect switches. Leave all off for a couple of minutes, then reset by closing the battery disconnects, turn on the inverter switch, and connect to shore power. My inverter was doing weird things a while back and I found this inverter reset procedure in the Beaver manual. Now all is right again with the inverter. Good luck!
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I attempted to reset the inverter: unplugged from shore power, opened house and chassis battery disconnects, and reset the inverter using the reset switch on the inverter. With the battery disconnects open, there was still power to the inverter and display. So, I also tried flipping the "salesman switch" at the door to try to kill all power. I then turned everything back on. No noticeable effect on the Battery Temp reading (still 151C).
However, after powering everything back on, I found I had no power in most of the interior: No power to light switches or thermostats or rear slides. However, the front slides work as do the front steps. After checking into this further, it appeared the solenoid for the "Salesmans Switch" appeared to be the culprit. After reading what others did with a similar problem - I ended up just connecting the input cable and output cable to the same terminal on the solenoid. That fixed the internal power problem.
So now the problem remains that the charger sits at "Float Charging: 12.6V / 0A" rather than 13.4V. The reason is likely the Battery Temp reading on the inverter of 151C - however even with the sensor unplugged, it remains at 151C which seems to point to a defective inverter. I'll try to contact Magnum to see if they have suggestions.
Thanks everyone for your input!
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Larry,
You have to disconnect the house battery + cable to remove power from the inverter as it sources 12v before the disconnect switch.
Steve
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I've been having the same problem on my '96 34' Monterey. Same symptoms. Checked same stuff. Finally pried the caps off the 4 month old Costco Interstate batteries and they were dry. I mean DRY! No water and long charge would bring them back! New batteries (which Costco would not honor because I didn't buy them..the seller did) were procured. Anyway, I didn't know about this BIRD thing..anyone tell me where I can find it on my model ?
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Your model may not have a BIRD system, Henry. Perhaps an ECHO charger, who's location apparently varies. Others here may be able to verify that and pinpoint the device for you on your coach. In the meantime on the menu line below your name/profile at the top of this page, choose the Search tab and run a search of the Forum for Echo charger for perhaps useful info. The Echo charger has been known to fail, assuming that's what's on your rig. Some mechanically injected engines may not have either a BIRD nor an Echo charger.
Regardless, your wet cell batteries may just have been neglected, or have been overcharged by a faulty system.
Joel
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Pretty sure you've got an Echo charger as Joel noted. Here's the manual for the Echo charger. It charges the chassis batteries when the house batteries are about 13V. There is a picture of it in the manual. Normally they were either mounted in the battery compartment or on the wall of the engine compartment access from the bedroom cover.
Steve
http://beaveramb.org/wp-content/uploads/2016/11/Echo-Charger-OwnerGuide445-0204-01-01.pdf
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Can't find it. Don't think it's working.
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Henry,
Your coach does not have a "BIRD" system, they were only installed on Monaco built Beavers. If it has anything, it will be an Echo Charger. On most of the 96 Monterey coaches, battery combining was accomplished by turn the ignition key to the accessory position to activate the boost switch. What are you trying to fix?
Gerald
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Quick update in case someone else has this problem in the future:
The symptom that I originally had was that the chassis batteries would go dead even when plugged into shore power and charging via the inverter/charger. I found that the inverter/charger would settle at "Float Charging: 12.6V / 0A". Consequently the Big Boy Relay would not engage and the chassis batteries would not charge when plugged into shore power.
This was caused by the Battery Temp Sensor reading 151C which would shut down the normal ~13.4V float charge since it indicated the batteries were overheating. Normally you could just disconnect the BTS cable from the inverter, and the BTS should then default to 25C and operate normally. In my case, it still registered 151C even with the BTS disconnected. This could only be caused by a defective Control Board in the Magnum inverter.
I purchased a new control board for $290, and swapped out the old control board. After hooking everything back up, I am back in business with normal inverter/charger operation. (Note - I also had a problem with the Big Boy relay in which I cleaned/burnished the internal contacts which fixed that problem).
Thanks everyone for your suggestions. Hopefully, this could help someone else out in the future.
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I had similar problems with my 2000 Monterrey--got tired of messing with the Echo charger and bought a Trik-L-Start, installed it, and haven't had any trouble since.