87Dolphin Posted March 18, 2015 Share Posted March 18, 2015 Hi. I have recently purchased a 1987 Dolphin. I absolute love it and have gotten familiar with mostly everything on board (appliances, water & waste systems, etc...Here is my issue...I would run my generator and plug the RV into it to run everything (ie. Fridge, water pump, 12v lights and electrical outlets). All was good. But when I would unplug from the generator, it would take anywhere from 5 mins to 1 hour for the coach battery to power on the 12v lights and water pump. This happened a dozen or so times. Then one day the coach battery never kicked on and I haven't been able to use the 12v lights or water pump without being plugged into a generator or to 110v power.Does anyone have any idea what could be up? Or can someone direct me to where this switch of power happens when I unplug?The coach battery is a couple of months old and is fully charged up.Any help would be appreciated....thx Quote Link to comment Share on other sites More sharing options...
Vanman Posted March 18, 2015 Share Posted March 18, 2015 There is a relay on the older converters that switches the RV 12V feed from the coach battery to the converters output. When no 120 VAC is going to the converter the relay puts the coach battery to the RV's 12V system. When you "plug in" and supply 120 VAC to the converter the relay puts the converters output to the RV's 12 V and switches the coach battery to a small charger mounted inside the converter. It could be that relay or a bad connection between the converter relay and the coach battery.On the older RV's like yours the relay is usually black, on my '91 it's blue. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 18, 2015 Share Posted March 18, 2015 It is common with age for the relay contacts to pit and hang up. When you kill the 120 volt power a spring returns the relay to the battery position. If yours has an open relay a small file can cure your problem it does however mean you have to get to it, it is inside of the converter/charger so be sure it is unplugged first! Quote Link to comment Share on other sites More sharing options...
87Dolphin Posted March 18, 2015 Author Share Posted March 18, 2015 Thank you. I thought it may be something like that. Do you know where the location of the relay is? Ps. I opened the fuse compartment on the power converter and cleaned the fuse connections and I got 12v power back! But I would like to know the location of the relay in case this happens again after disconnecting from 120v. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted March 18, 2015 Share Posted March 18, 2015 The better the information you give the better the answers will be (maybe). What make and model converter do you have? Quote Link to comment Share on other sites More sharing options...
87Dolphin Posted March 20, 2015 Author Share Posted March 20, 2015 Thanks for responding. It's a Progressive Dynamics...model # PD723Q08RMT Quote Link to comment Share on other sites More sharing options...
Derek up North Posted March 20, 2015 Share Posted March 20, 2015 Hopefully these will be useful. "Covers: PD720Q thru PD723Q, PD731Q thru PD738Q, PD731 thru PD733, PD743 thru PD746, PD753 thru PD756, PD761Q thru PD768Q, PD773 thru PD776, 7220, 7231, 7338, 7348, 7648 and 7655." http://www.progressivedyn.com/discontinued_prod_basic_operation.html PDI Service Manual 710778.pdf PD720Q - PD723Q MANUAL.pdf Quote Link to comment Share on other sites More sharing options...
zero Posted March 20, 2015 Share Posted March 20, 2015 Thanks for responding. It's a Progressive Dynamics...model # PD723Q08RMT Here's a diagram showing the relay. If it's clicking when engaged but not powering on, the contacts are likely bad. If it was mine, I'd just wire it for manual contol like many came new. Quote Link to comment Share on other sites More sharing options...
87Dolphin Posted March 20, 2015 Author Share Posted March 20, 2015 Thanks to the both of you for your help. Very useful information. Much appreciated. Cheers Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 20, 2015 Share Posted March 20, 2015 Frankly the best thing you can do is replace it with a modern 3 stage charger your batteries will thank you. Depending on your charger they had two types one with an open frame relay the other had a sealed relay meaning there was no fixing it. It had to be replaced if it was hanging up. The older units had very poor voltage regulation and had a tendency to boil the water out of the battery pretty much making it impossible to leave the camper plugged in to keep the battery charged properly. They also have no relays and recharge at a far faster rate. Quote Link to comment Share on other sites More sharing options...
TheChief Posted March 25, 2015 Share Posted March 25, 2015 As usual, you guys are going to have to forgive my newbie ignorance here, but since the topic of coach batteries and 12-volt systems was brought up, I was hoping someone might be able to educate me. I have a 1984 Toyota Dolphin that I bought last year and have taken out on only one trip, so I'm still in the learning mode. I grew up as a kid spending the summers in my granddad's motorhome but I'm quickly finding out that his high-end Monaco was a lot different than my little Toyota is, so I'm having to re-learn things all over again. Here is my understanding of things, please correct me if I am wrong on any of this; the coach battery will charge up whenever you are connected to an outside power source (shore line or generator) or from the vehicle's alternator when the motor is running. If you are connected to an outside power source (shore line or generator,) that will power the coach. When you are just sitting, parked and not connected, you are running off of your coach battery. So, when I am running down the road and use electricity in the coach, does the alternator in the vehicle power those things, is it pulling the coach batteries down, or is it dependent on other factors? My follow-up to that would be, can I run my (electric-only) mini-fridge while driving down the road? I don't want to do something to ruin my battery or overtax the vehicle's electric system, but otherwise is my fridge (since it isn't LP fueled) basically a fancy cooler from the time I pull out of the driveway until the time I plug in at the campground? Quote Link to comment Share on other sites More sharing options...
WME Posted March 25, 2015 Share Posted March 25, 2015 What is the voltage requirement for the refer?? 110v AC or 12v DC?? Quote Link to comment Share on other sites More sharing options...
TheChief Posted March 25, 2015 Share Posted March 25, 2015 110. It's just a regular residential mini-fridge. Quote Link to comment Share on other sites More sharing options...
WME Posted March 25, 2015 Share Posted March 25, 2015 Some where you have an inverter to convert the 12v DC to 110v AC to run the refer. Look and see how much power the refer takes. There should be a label that says how much it uses, either in watts or amps. Rough estimate is a 3 amp refer is using 30 amps of 12v power to make it work. You have a 40 or 60 amp alternator. So at night you could be cutting it close. A large battery will help buffer things. If you forget to turn off the refer it will kill a battery in a couple of hours. So plug in asap. The rest of your thoughts are correct. Quote Link to comment Share on other sites More sharing options...
zero Posted March 25, 2015 Share Posted March 25, 2015 So, when I am running down the road and use electricity in the coach, does the alternator in the vehicle power those things, is it pulling the coach batteries down, or is it dependent on other factors? My follow-up to that would be, can I run my (electric-only) mini-fridge while driving down the road? I don't want to do something to ruin my battery or overtax the vehicle's electric system, but otherwise is my fridge (since it isn't LP fueled) basically a fancy cooler from the time I pull out of the driveway until the time I plug in at the campground? I've used a small AC refrigerator for years in one of my RVs. It is hooked to a 1200 watt AIMs mod-wave inverter and has worked flawlessly. That RV has a 62 amp alternator and running with the frig on all that time, at night, with all the lights on too, has never been an issue. When hooked this way, amp draw @ 12 volts will be 8-12 amps when the refrigerator is running which is no big deal. If you add some 1" or 2" foam around the frig for extra insulation, it will rarely come on anyway when driving. As far as your coach battery goes . . Usually you drive with the converter turned off and all the 12 volt equipment that is hooked to the converter control-center runs off the "house" battery. That battery is constantly being charged by the RVs alternator while driving. Quote Link to comment Share on other sites More sharing options...
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