SanDiegoPaul Posted November 2, 2007 Share Posted November 2, 2007 The previous owner of my RV just put in a new coach battery, and it is a Deep Cycle one which I know is correct. I'd like to know if there is any chance that this deep cycle battery does charge with the engine alternator? The charging system on my '85 works fine and keeps the engine battery charged well. I did notice my coach battery went dead after leaving the refrigerator on 12V for a few days. It charged up fine when I plugged the RV in to 110V. But is it supposed to get any charge at all, from the Alternator? There is no generator on my motorhome. Thanks Paul in San Diego Quote Link to comment Share on other sites More sharing options...
bufbooth Posted November 2, 2007 Share Posted November 2, 2007 Hello, On my rig, the coach battery does get charged by the alternator. However, I may have a couple problems, in which you might have one of them. I have some sort of power drain that will also run my coach battery down if the my Toyota sits for 2 or 3 weeks. In addition, my engine mounted battery isolator may not be working since my truck battery will also drain down. For a short term fix, I installed a $5 battery disconnect that mounts directly on the battery post, when I park the Toyota for more than a week, I will disconnect the batteries by a 2 second twist of a knob. Dennis... Quote Link to comment Share on other sites More sharing options...
SanDiegoPaul Posted November 2, 2007 Author Share Posted November 2, 2007 Hello, On my rig, the coach battery does get charged by the alternator. However, I may have a couple problems, in which you might have one of them. I have some sort of power drain that will also run my coach battery down if the my Toyota sits for 2 or 3 weeks. In addition, my engine mounted battery isolator may not be working since my truck battery will also drain down. For a short term fix, I installed a $5 battery disconnect that mounts directly on the battery post, when I park the Toyota for more than a week, I will disconnect the batteries by a 2 second twist of a knob. Dennis... Yea battery disconnects are a good thing. Also a theft deterrent. I havent' had mine that long yet (a month) but so far, the engine battery appears to be just fine. And the only time the coach battery went down was when I tried to see if the fridge worked, and I left it on the 12v setting for several days. I haven't let it sit for weeks on end yet because I'm always doing something to it! Quote Link to comment Share on other sites More sharing options...
picklebill Posted November 9, 2007 Share Posted November 9, 2007 Paul - If you leave the fridge running on 12V it will draw about 12 amps. This will definitely run the coach battery down pretty quickly. I am surprised you got 3 days out of it. When your RV is plugged into 120VAC the converter should keep the coach battery charged. Bill Quote Link to comment Share on other sites More sharing options...
SanDiegoPaul Posted November 9, 2007 Author Share Posted November 9, 2007 Paul - If you leave the fridge running on 12V it will draw about 12 amps. This will definitely run the coach battery down pretty quickly. I am surprised you got 3 days out of it. When your RV is plugged into 120VAC the converter should keep the coach battery charged.Bill Thanks - but I've all but given up on the fridge now. All it does is gurgle but never gets cool inside. I haven't tried it yet real level and may try that one more time before giving up. So far, I've just settled for "comfortably level" but I know these things are supposed to be absolutly level instead. My main focus is the hot water heater now. Cant' get the pilot to light no matter what. I can live w/out the fridge but it would be great to have hot water! Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted November 18, 2007 Share Posted November 18, 2007 The coach battery usually does get a charge from the alternator. The old style which you might have is a big mechanical solenoid located somewhere on your engine side firewall. They do fail. The other type is a battery isolator. It is a electronic type switch. The difference between the two is how the batteries recieve a charge. The mechanical solenoid basically connects the batteries in parallel. The disadvantage of that is when one battery is less charged both get the same charge rate, bottom line is the fully charged battery gets over charged. The electronic battery isolator can direct a charge to the battery that needs the charge without over charging the other. And there are no mechanical contacts to fail. To check if the coach battery is getting a charge you will need a volt meter that can read at least 18 volts dc and take a voltage reading at the coach battery with someone revving the engine a bit. The voltage should be 13 volts or higher, hopefully 14 volts and up. Also note that discharging and charging a lead acid battery will create explosive gases so be careful. No sparks in the battery box! Also a battery discharged down to 11 volts or lower for an extended time period will cause whats called sulfation on it electrical plates. Once that happens, if its too bad then the battery just never works right anymore. It only takes a few days. Any how there is a chance your solenoid is bad or someone disconnected something. Your refer Get a bulls eye level and set it on the freezer tray. If its close to level with in an hour the freezer tray should feel cold and start to freeze drops of water. Run it on the gas side and not 12 volts. 12 volts is OK for going down the road but beware even a small traffic backup with the engine running slow can drain the charge from the battery fairly quickly. And if you have the mechanical type solenoid it drains both the coach and truck battery. Another advantage of the electronic battery isolator, hence the term isolator. So if you get the thing level and still no cold the gurgling sound might mean you have a bad refer. The actual cooling unit can be damaged beyond repair if run in a not level position for to long. The chemicals in the cooling system can solidify. Once that happens it time for a new refer or cooling unit. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted November 18, 2007 Share Posted November 18, 2007 I am new at this, but mine has a box on the backside of the fridge you can open from the outside of the RV. There is a plug, to see if the fridge is killing your battery you could unplug it for a few days and see if the battery holds a charge. I could tell mine was drawing current when I first bought it as the battery charger had a big spark when I attached it. That usually means it is drawing current somewhere, I searched around until I figured out the fridge had been on. Once I bought a plug adapter I plugged the RV into my house, I just the left the fridge on and eventually it started to get cold, but it seemed to take a day and a half to get real cold but it works good now. And my spare battery also got charged. I have heard with home fridges that power must be off, and level and let it settle for a time before restarting, I am not HVAC rated or anything but I did hear something to that effect once. Good luck! Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted November 18, 2007 Share Posted November 18, 2007 There is a plug, to see if the fridge is killing your battery you could unplug it for a few days and see if the battery holds a charge. What kind of plug? Does it look like a regular plug for house current. Refers come in two flavors. One can use gas, 120 volt AC (like your house) and 12 volt DC from the battery. The other is only gas and 120 V AC. Here are some pics of 120 and 12 volt heater elements This image is with the elements inserted into the heat transfer tubes Quote Link to comment Share on other sites More sharing options...
Supurcar Posted November 19, 2007 Share Posted November 19, 2007 (edited) What kind of plug? Does it look like a regular plug for house current. Refers come in two flavors. One can use gas, 120 volt AC (like your house) and 12 volt DC from the battery. The other is only gas and 120 V AC. Here are some pics of 120 and 12 volt heater elements This image is with the elements inserted into the heat transfer tubes Well here is a pic if it comes thru. It is like a wall socket, when I unplugged it I had no more current drain on my battery, until I found the off switch inside the thing a few days later. Again I am new with this thing and learning as I go, and trying not to break anything as I learn. I did notice a converter panel down below my sink, it looked real clean and in good order. My stove finally lit today, I did not wait long enough for the gas to travel to the burner last time when I tried to lite it. So once I fix the gas gauge (my last project) I am ready to take it on a road trip. Edited November 19, 2007 by Supurcar Quote Link to comment Share on other sites More sharing options...
SanDiegoPaul Posted November 19, 2007 Author Share Posted November 19, 2007 Well here is a pic if it comes thru. It is like a wall socket, when I unplugged it I had no more current drain on my battery, until I found the off switch inside the thing a few days later. Again I am new with this thing and learning as I go, and trying not to break anything as I learn. I did notice a converter panel down below my sink, it looked real clean and in good order. My stove finally lit today, I did not wait long enough for the gas to travel to the burner last time when I tried to lite it.So once I fix the gas gauge (my last project) I am ready to take it on a road trip. That's how mine is. Wall Socket. When I shut the fridge off, the battery stayed up just fine. I had just forgotten that it was on when it discharged the battery the first time. Since then I've run it on 110V power and it still doesn't get cold, so I'm going to just forget about it for now. Bigger fish to fry than that right now! Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted November 20, 2007 Share Posted November 20, 2007 That's how mine is. Wall Socket. When I shut the fridge off, the battery stayed up just fine. I had just forgotten that it was on when it discharged the battery the first time. Since then I've run it on 110V power and it still doesn't get cold, so I'm going to just forget about it for now. Bigger fish to fry than that right now! Supurcar - Hmmmm - Unless someone has done some fancy rewiring of your rig that plug is for the 120 volt AC side of your refrigerator and not the battery. If you want to verify that it is 120 volt ac plug your motorhome into shore power and plug something like a lamp or drill or hair dryer from your house into that outlet and see what you have. Now your refrigerator source selector knob will have two or three selections. "Gas - !2V - 120V" 12V being battery and 120V being shore power. Two selections is "Gas - 120V". I have never seen a gas and battery powered refer but maybe I am wrong. SanDiegoPaul - Your 120 Volt AC element could be bad or a bad thermostat switch that powers the element. Worst case scenario is a bad cooling unit. One way to verify is to fire it up on gas. Make sure the freezer tray is level. Converter 101: There will be a dedicated circuit breaker inside your converter door for the refrigerator circuit. It is 120 Volts AC just like your house. Now when you connect your rig to shore power the converter has an internal relay (6300 series) that will make a distinct clunk when it engages. When you plug into shore power this relay takes your coach battery out of the circuit for all of your 12 Volt DC circuits and supplies its own power to them. It also connects the converters battery charger to the battery. When you disconnect from shore power the relay then re connects all your 12 volt dc stuff back to the battery. That's how its supposed to work, a previous owner could have done some fancy rewiring. Hope I have not created more confusion. Last thing, don't be afraid to ask any questions if something is not clear. That's why we are all here for! Greg Quote Link to comment Share on other sites More sharing options...
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