Dead Battery When Towing
When towing my PT Cruiser, I use a BrakeBuddy supplemental braking system. I have a 20-amp charge line coming from the motorhome’s house batteries to the towed vehicle. I pull the PT Cruiser’s fuse as required when towing, and I turn off the radio, heater, and air-conditioning. But after a couple hours, the battery will be dead. Do you have any suggestions to remedy this problem?
Paul May, F243341
Kemp, Texas
If the PT Cruiser’s battery is being run down after just a few hours, the charge line is not charging the car’s battery. If the charge line is connected and there were other problems, the car’s battery might still die, but it would take much longer. It appears on the surface that you are doing everything right — pulling the fuse, using a charge line, etc. — so I think the problem could be a faulty charge line.
Depending on the length and gauge of the wire, it’s quite possible that the voltage that’s coming from the battery is significantly less than what is being fed to the towed vehicle. You might start your investigation by measuring voltage coming from the battery and then at the terminus of the wire with a voltmeter. If you find a significant drop in voltage between the two, you may need a lower gauge of wiring, particularly for long wire runs.
Was it fused at each end, as I’ve recommended several times in this column? If so, check each fuse. If both fuses appear to be okay, you will need to find the electrical disruption in the charge, and to do this will require a 12-volt-DC circuit tester (available at auto parts stores). Much like checking for a water leak, you need to follow the charging circuit from the source (the motorhome’s battery) to what is being charged (the PT Cruiser’s battery). Make sure the circuit tester has a good ground (touch the tester’s point to the plus terminal on the motorhome’s battery) and then test the downstream side of the first fuse with the fuse in place. If it’s good, then test the circuit at the motorhome’s connector. If that’s good, plug the connector cable into the motorhome and test the PT Cruiser’s end of the connector cable. If that’s okay, check the downstream side of the second fuse. If there’s no juice at the fuse, the problem is either a blown fuse or an open line between the car’s connector and the fuse, or the PT Cruiser’s connector is bad. If your readings test out good on both sides of the fuse, disconnect the line at the PT Cruiser’s battery and test the line. If there’s power all the way through, that means the circuit between the two batteries is good and the car’s battery should be tested.
Battery Charging
I have a 2007 Safari Trek on a Workhorse chassis that I purchased three years ago. I recently found out that the chassis battery does not charge when the unit is plugged in to shore power, which caused some inconvenience over the past winter. Is there a simple means by which the chassis battery can be recharged while the house batteries are being charged when on shore power? I keep it on shore power at all times. It appears to me, upon looking at the schematic provided in the owners manual, that bridging across the battery boost solenoid would complete the circuit to the chassis battery and allow it to receive the same charge as the house batteries. Would this potentially harm the chassis battery?
Ron McClellan, F426164
Olathe, Kansas
Depending the way the wiring was set up by the motorhome manufacturer, the chassis battery, when on shore power, can charge after the house batteries are fully charged. You will need to verify through the company or a wiring schematic whether your motorhome was set up for the chassis battery to charge through shore power. If you have determined that your electric is set up this way, perhaps your converter or inverter — depending on which one is in your coach — has gone off-line. You should check all your chassis fuses and circuit breakers first. If they are all good, you may need a qualified technician to work on the house wiring in your coach — you don’t want to have major problems down the road.
As a short-term fix, if you have access to the chassis battery pack, you can connect a 120-volt-AC battery charger to the batteries and hook the battery charger to shore power via an extension cord to the 120-volt-AC outlet on the post.
Battery Facts
I have a 2005 33-foot Itasca Suncruiser motorhome. I am about ready to replace the coach batteries. I am tired of messing with lead-acid batteries that require watering. Is there any downside to using absorbed-glass-mat batteries? Do they require any special type of converter/charger? I have recently upgraded to a 65-amp WFCO converter. H0w do glass-mat batteries compare to the lead-acid batteries I am now using? I do some dry camping where I have to run the generator to charge the batteries. Thank you for any help you can give me.
Don & Terri Hubner, F243708
Oak Harbor, Washington
I have used absorbed-glass-mat (AGM) batteries in my current motorhome and previous two coaches and have been very pleased with their longevity — the current batteries are 5 1/2 years old and are still very strong. I never discharge over 50 percent. Other than keeping the tops clean, there is virtually no maintenance.
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