BAC Forum
General Boards => Technical Support => Topic started by: Bruce Sieloff on September 14, 2016, 09:20:37 PM
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Must be the time of the year for battery problems. My DW is threatening to put a bomb under the coach. When trying to move out we suddenly had what has turned out to be 2 problems. After airing up, we turned off the engine and attempted to raise the jacks and bring in the slides, but neither worked - unless we used the coach batteries to boost power. The next time we tried to turn off the engine, it started but the ignition key would not turn it off, so we killed it by turning off the chassis batteries. I replaced the clearly worn ignition switch which now works as it should. The second problem is that our new no-maintenance chassis batteries aren't getting power to the starter and we had to use the coach batteries to boost for starting. We had the chassis batteries checked at Interstate Batteries and they were fully charged and putting out 1000 cca so it is not a battery issue. I reinstalled the batteries and replaced the continuous duty solenoid with a NAPA unit (for a Ford F-350) since many of the symptoms noted in the thread are also present in our coach. No effect. I have 12V at the batteries but have only 11V at the big red cable on the solenoid. Something downstream from the batteries is causing resistance. If I turn on the chassis batteries and put the key in ACC nothing on the dash works, the power visors go down but not up and no reaction from the instruments nor buzzer from the low air warning. Cranking the engine is met with silence. I can get the coach to start and pull in the slides using the boost switch, but the chassis batteries are not on line. I'm stymied. I intend to run the coach 60 miles down to my friendly Freightliner dealer on Friday using the coach batteries (and hopefully not get stranded), but before I get nailed at $130/hour (AGAIN), does anyone have any suggestions??
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Bruce,
12V is not a fully charged chassis battery. Try running your generator and check battery and solenoid voltages after 15-30 min or so. If 13+v at battery, try starting.
Steve
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Steve,
Not sure the Park would be happy about the generator test.
Batteries test out at 12.87, we have been plugged in to shore power for several weeks.
We still get no dash action at all, I'm concerned about the total lack of power (in particular the low air warning) when you turn the ignition to ON.
I have had a slow cranking condition manifest itself before, but never a complete lack of response.
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Bruce,
It sounds like you have a poor connection in a battery cable or the chassis battery cut off switch. The only way to determine where your problem is located is to take a volt meter and trace the circuit. You may need to have someone try to crank the coach as you check for voltage drop at each splice or connection.
Gerald
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Bruce,
The solenoid you replaced, is that at the bottom of the copper busses in the electrical bay under the drivers seat area?
When you get down to no click at the starter using the chassis batteries but the boost will work that makes me think that the control circuit from the front of the coach is not capable of supplying enough voltage to the starter circuit at the starter solenoid coming from the ignition switch. I'm not sure if using the boost is working because it is giving just enough extra voltage/current to better fire the solenoid at the bottom of the copper busses to get the ignition circuit and dash online, or if they are required to crank the engine because the chassis batteries are not well charged. If the dash is not coming online then the starter solenoid small wire that fires it is not coming online either.
The boost uses the same large cable wiring going to the starter as the chassis batteries do without boost. With whatever online chassis batteries charging source you have while plugged into AC 50 amps, are you getting 13V to the chassis batteries(Steve's thought)? If not that has to be fixed to get the chassis set fully charged.
I would clean the chassis batteries terminal posts using a wire brush tool to rule that out. I would try a physical jumper wire between the large terminals on the solenoid at the bottom of the copper busses to rule out that internal contractor, if you have not changed that solenoid out.
To get a test to see if the chassis battery wiring set is working use a jumper cable between the 12V of the house set and the 12V of the chassis set and wait a minute to bring some charge into the chassis set and see if the coach starts properly. That would rule out most all wiring issues except charging of the chassis set, the chassis batteries, and posts. Hope this helps.
Later Ed
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I now have a working chassis battery switch after cleaning all the lugs and terminals at the switch. The transfer switch is testing fine and the chassis batteries will charge off the generator but won't charge off shore power. I have a new echo charger in place. How can the chassis battery charge off the generator but not off shore power? Does the generator go around the inverter? Should I be testing the inverter for charging function and if so where?
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Bruce,
When on shore power, what are the voltages seen on the house and chassis batteries? Also, what is the status of the light on the
Echo Charger?
Steve
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Echo is steady green, coach Batteries are 6.99v at the battery bay, chassis are 12.52. Aladdin says coach Bat's are 13.9' Chassis were 13.2 on the generator.
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Bruce,
Echo Charger should be charging chassis batteries with about 15A of current. Give it an hour or 2 and see if chassis bats reach about 13.2 v.
Steve
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Problem solved, Gerald nailed it, turned out to be a loose battery ground on the chassis batteries. Hidden a bit near the divider between battery banks and attached to the frame rail by a big wing nut (!) it was cleaned up and tightened and now the chassis batteries are charging at 13.6 V. Happy camper here. Thanks for all the support, apparently I need to get on a ground/connection regimen to keep all my contacts clean. Clean now or gnash later.
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Bruce,
On thing that I did that you might consider also, is to run a battery cable (same gauge as what you have now) between a battery ground lug of the house set to the battery ground lug of the chassis set. That gives you a redundant ground path using the house battery connection to the frame and reduces the total resistance of the current path to the starter.
It is an inexpensive change that would have kept you going until you did some maintenance and found the loose connection.
Wing nuts have a tendency to vibrate loose, you should consider using an air craft style nut with a nylon insert or one of the other style locking nuts to keep it tight.
Later Ed
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Talk of speaking too soon, after sitting for 3 days I am still not getting a charge on my chassis batteries, they had 6.6V this morning. New Ground wasn't it. Ran the generator for an hour to get them up to 12.7V. My new echo charger doesn't seem to be doing the job. I get 14.4 V on the red coach battery wire (this is inserting my probes in each flag terminal, basically making it part of the circuit) and a 12.0V (and dropping) on the red striped wire for the chassis battery side. The black ground wire shows 13.5V. Since the echo charger isn't wired for all the amperage the coach side can produce I can only assume that the next thing in line is a solenoid that handles the real current and the Echo is only the brain. There is a solenoid mounted at the upper rear of the battery box that seems to be connected to a blue anodized heat sink. Am I right in assuming that this is the "switch"? I read 12.5V on one side (Side big terminal to nearest small terminal) and nothing on the other when plugged into shore power. If this is the switch and the chassis batteries are depleted then this should be active, yes?
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Bruce,
If you have 14.4 across the house battery bank (two 6V in series to ground measurement) that is good and your house batteries and charger are fine. The blue heat sink has three terminals, it takes the charging lead from the alternator and feeds both house and chassis battery + leads and its function is to block current from one battery set from transferring to the other so if you had a bad battery it would not drag them all down. That is most likely OK and does not weigh into your problem.
The Echo Charger is a current limiting switch which gets its cue as to what to do from voltage levels on both battery banks. In general if the chassis batteries need charging as measured by the voltage level at the chassis bank and the house bank voltage level is up to snuff (in your case 14.4V which is fine) then the chassis set should be charging ultimately reaching 13-13.5V. So three things can happen here, a bad fuse in one of the red or red stripe wire sets or you have a chassis battery that is bad and 15amps will not be able to handle that load and charge, or the Echo Charger is bad which will usually show a blinking or no led light. I am not sure about the black wire showing 13.5V that black wire goes to chassis ground if it is the Echo Charger wire and is at 0V. Check the fuses, check the Led status, have a load check of the chassis batteries to see if they are good.
Later Ed
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Ed,
Fuses are fine. Had batteries load tested a week ago, no problems. LED indicator is steady green no matter what the chassis batteries read; it used to blink when the chassis batteries were low, but that isn't happening. Pretty sure the ground wire should not be carrying voltage. All the common tests indicate the Echo is OK. Bad Echo?
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Bruce,
Very specifically between chassis ground (negative battery post chassis set) and (+ of the chassis set) what voltage do you measure? Same for house set at the 12V end of the series parallel pairs? Does the black wire from the Echo Charger screw to the frame of the coach in some way with a clean tight contact?
If the fuses are good, the ground is good, the chassis batteries are good then the most likely issue is a failed echo charger. The ground 13.5V throws me because that is impossible if the Echo Charger black wire is connected to a solid chassis ground. How did you get that reading probe wise, please check it again. The only other possibility is you have a load still on the chassis set that exceeds say 10 amps and the Echo is trying but cannot keep up, that takes an ammeter to check out. Any chassis battery loads turned on that you know of?
Later Ed
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Chassis battery pair is producing 12.36V right now (I have had it on a 15 amp battery charger for most of the afternoon), The Coach battery pairs are producing 14.02V. The Echo Ground wire when disconnected from ground and tested with one probe at the Echo and the other to any common ground is putting out 12.5V. Contacting Xantrex they said it is unlikely the Echo is the issue, I must have a positive lead going to ground somewhere, although I don't know where, I've been careful to avoid mixed connections. I have no idea how a ground wire coming directly out of the Echo can produce voltage unless there is something wrong with the Echo. No chassis battery loads that I can find. I am going to disconnect the Echo charger and watch the chassis batteries for continued discharge, maybe the Echo is pulling voltage from the chassis batteries and routing it to ground.
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Bruce,
In order to get a good reading you should not be disconnecting the ground wire from the coach chassis ground. It is a reference 0V ground connection that is used by the Echo Charger. All measurements are taken from the ground lead of the Echo charger connected to chassis ground (black probe). The red probe to the + battery post of the battery banks. At 14V the house set are OK.
All you need now, with all Echo Charger leads connected, Red wire to house battery bank + 14V post, Red stripe wire to chassis + battery post, black wire screw lug to frame ground, is to measure the chassis + battery post to ground. You can use the Echo Charger black lead frame connection or your chassis battery negative post for the ground measurement point, readings should be the same.
Your portable charger needs to be disconnected and wait maybe 1/2 hr before taking the reading with the Echo Connected. If that value is not 12.8 to 13.8V then your Echo Charger is defective. That voltage range is wide based on the charge state of the chassis battery set affects this value. Eventually they should be 13V+ while using the Echo Charger when fully charged.
The only other cause of low voltage is if a chassis battery is bad and you have had them tested so that should rule that out. Let us know what you find.
Later Ed
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Ed,
Today is moving day. I did the test as you described and am pulling 12.1V at the starter batteries and between the + post on the starter side and a ground on the house side. Same readings. I currently have the generator running to charge the starter side and will test again when we get settled. Don't expect any magic. The 13 volt draw still concerns me. I have done several swaps of the solenoid in the electrical bay, I don't think I swapped any wires but just as a check, which terminal does the ignition ground go on as you face it, FWD or aft?
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Bruce,
I think the Echo Charger is bad if you only have 12.1V and your chassis batteries are good and your house set are being charged at 14V when you took the measurement. Not sure what you mean by 13V draw, if that is ground wire lifted off chassis from the Echo Charger and measured to ground do not worry about it. You can have voltage there without current flow when lifted.
Unless the generator has its own alternator, or the Echo Charger is working, there will not be a charging source to the chassis battery set with the generator running. Some had a built in alternator but most did not.
The two solenoid small terminals should have a diode across them. The diode end with the bar on it should go to the + 12V side, the other terminal would be the ground.
Later Ed
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Bruce,
There seems to be a misunderstanding here in the definition for electrical terms. This may put them into nontechnical language.
Voltage is the electrical pressure that pushes the current or electrons through the circuit, and it is not a measurement for the amount of electricity that travels through a circuit.
Amperage is a measurement for the volume of current that travels through a circuit.
Ohms is a measurement for the resistance to the flow of current through a circuit.
Therefore, as you can see from the descriptions above, the presence of voltage in an open circuit (disconnected wire) does not mean that it is the source of a battery drain problem. The circuit may only be flowing an amperage in the milliamp range because of a high resistance, but it could still have full system voltage when disconnected.
Gerald