83 SunRader Posted December 30, 2012 Share Posted December 30, 2012 Hi everyone, I recently purchased an inverter to use with my laptop and have been using it for an hour or two a day for over a week and it worked as I had expected. Then yesterday I used it for a 4-5 hours and drained the “house” battery to about a ¼ charge and because I didn’t want to drain the battery down all the way I shut it off. When I went to start the truck nothing, 2 dead battery. Why isn't there some kind of protection for draining BOTH batteries! I had any idea, why not run the generator an hour or so and see if it will charge the battery enough to start the truck. Wahoo! It worked or at least something worked I had enough juice to start the truck so I headed to my next destination. I didn't go 5 miles before my radio started to go haywire, then the headlights started to dim and I knew something was wrong. I also knew that the truck was just going to die once I shut it off and I was right. Well the genie thing worked again this morning enough to get the truck started and off I went to the nearest auto store to test the batteries and alternator. The batteries tested fine so it appears as though the alternator is fried. Does that sound correct? It's 5 years old. Another interesting thing was when I ran the genie and the batteries were dead the converter made what has been called a banjo twang (there is a post about it on this forum). Interestingly after the guy at the auto parts store charged my truck battery the converter does NOT make the banjo twang anymore, but It doesn't appear to be charging the "house" deep cycle battery now. Do you think I'm going to need to replace the converter or could it be a breaker or a fuse? If I need to replace it what converter should I be looking for? Thanks for any help you can give. Bye the way I'm full time with a 83' Sunrader, 22R, 2 batteries, 25 amp converter/charger model 6325 Quote Link to comment Share on other sites More sharing options...
Boots Posted December 31, 2012 Share Posted December 31, 2012 Hi SunRaider, On my rig, there is a battery isolater, in the engine compartment, which isolates the engine battery from the coach battery, in certain conditions. It works like this, engine is started and the alternator starts to replace the power used for the startup and to supply power to the coach battery, it measures both batteries for voltage and if one or the other (or both) require more current to bring up the voltage, the alternator output is adjusted to do so. Generally speaking this is happening continuously when you are running, however, when you shut off the ignition, a switch running from the ignition is opened, there is a loss of a 12 volt signal and the isolator is disconnected from the alternator source. From that point on any current draw from the coach battery is drawn strictly from the coach battery. The car battery is completely cut off from any demands and is preserved for the engine functions only. You can buy these devices from most local autoshops, such as Napa and install it in the engine compartment. If you are handy it is not too complicated (except for locating the ignition switch wire) - the other thing to do, while you are at it, is to measure your alternator output, and see if it is sufficient for your normal needs. Most Toyota alternators put out about 40 amps and this is generally all you need. I went to an alternator shop near where I live and they said they could rebuild my alternator to increase out put (up to 150 amps) for around 150 dollars. I bought a 225 amp Trojan battery for my rig, and easily run for two to three days, I am considering swapping out my stock charger for a more modern unit that is multi-staged and temperature sensing, to increase the battery life. My rigs stock charger is purported to put out 32 amps, but I have never checked that measurement. One of the advantages of the newer units is they can be ordered in capacities up to 65 amps, however, there is a danger of overheating the battery, and that can damage the battery - of course that is the reason for a battery temperature monitor, it can react to overheating and cut back as needed. The benefit of this is you can rapidly charge a battery in a relatively short time, say in three hours instead of eight hours. Let me know if this helps Brian Quote Link to comment Share on other sites More sharing options...
stamar Posted December 31, 2012 Share Posted December 31, 2012 The banjo twang comes from the house battery being wired backwards.... what's funky is that the lights work . However I don't believe an inverter will work wired backwards its usually set up to not work that way. So going by your story.... I'm not sure. I believe what's happened is first your house battery sucked out too much juice when you tried to start it or you just don't have an isolater relay... Then after taking it out you hooked the house battery up backwards. That seems to be what you said. Get a cheap ohm meter to test the alternator, but I believe you're kkilling the house battery because its wired backwards now. Its probably ruined also just takes a couple days retest the battery now Quote Link to comment Share on other sites More sharing options...
stamar Posted December 31, 2012 Share Posted December 31, 2012 In the event your alternator is bad though like the previous poster said ebay has 60 amp replacement alternators for cheaper than the auto parts stores regulat replacements. Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 1, 2013 Author Share Posted January 1, 2013 On my rig, there is a battery isolater, in the engine compartment, which isolates the engine battery from the coach battery, in certain conditions. It works like this, engine is started and the alternator starts to replace the power used for the startup and to supply power to the coach battery, it measures both batteries for voltage and if one or the other (or both) require more current to bring up the voltage, the alternator output is adjusted to do so. Generally speaking this is happening continuously when you are running, however, when you shut off the ignition, a switch running from the ignition is opened, there is a loss of a 12 volt signal and the isolator is disconnected from the alternator source. From that point on any current draw from the coach battery is drawn strictly from the coach battery. The car battery is completely cut off from any demands and is preserved for the engine functions only. I'm not exactly sure if I already have an isolator, I do have a couple of components on the side wall of the engine compartment so I took a picture maybe someone can help figure what they are. Thanks again! Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 1, 2013 Author Share Posted January 1, 2013 The banjo twang comes from the house battery being wired backwards....what's funky is that the lights work . However I don't believe an inverter will work wired backwards its usually set up to not work that way. stamar I don't think the battery was wired backwards since I have been full time in the RV now for almost two months and haven't had any problems until I drained the "house" battery down to a 1/4 charge. I'm currently trying to figure out if I have an isolator installed. I read the original post about the Banjo twang and what I found most interesting was that once the truck battery was charged again the banjo twang went away. Quote Link to comment Share on other sites More sharing options...
zero Posted January 1, 2013 Share Posted January 1, 2013 Why isn't there some kind of protection for draining BOTH batteries! I had any idea, why not run the generator an hour or so and see if it will charge the battery enough to start the truck. The batteries tested fine so it appears as though the alternator is fried. Does that sound correct? It's 5 years old. Another interesting thing was when I ran the genie and the batteries were dead the converter made what has been called a banjo twang There IS supposed to be a battery isolator that keeps your starting battery separate from your RV storage battery. Either its not hooked up or it's defective. As to your alternator working? Might of failed but the problem can also be a failed isolator. if you have a rectifier based battery isolator and it goes bad - it can prevent the alternator from charging ANY of the batteries. In regard to your twang? It might be from poor power supplied by your electric generator. Many small gas powered generators put out low voltage. Good enough to run most 120 VAC appliances but often 20 volts low. You can check your alternator easily and quickly with a volt meter AT the alternator output post OR the isolator input post. Needs to be 13.8 to 14 volts when the engine is running. Quote Link to comment Share on other sites More sharing options...
zero Posted January 1, 2013 Share Posted January 1, 2013 stamar I don't think the battery was wired backwards since I have been full time in the RV now for almost two months and haven't had any problems until I drained the "house" battery down to a 1/4 charge. I'm currently trying to figure out if I have an isolator installed. I read the original post about the Banjo twang and what I found most interesting was that once the truck battery was charged again the banjo twang went away. Low input voltage can make some converters humm or "twang" something awful. A dead house battery putting a huge demand on a small converter will also make it hum badly. Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 2, 2013 Author Share Posted January 2, 2013 There IS supposed to be a battery isolator that keeps your starting battery separate from your RV storage battery. Either its not hooked up or it's defective. jdemaris thank you very much for your input. Did you see the picture I posted yesterday? I'm trying to determine if one of the components in the picture is an isolator. Can you tell? Bye the way, I replaced the alternator on Monday and everything is working fine again after the batteries were recharged. Quote Link to comment Share on other sites More sharing options...
stamar Posted January 2, 2013 Share Posted January 2, 2013 in that picture you dont have the stock isolater relay that most toyhomes have http://www.amazon.co...=isolator relay but the thing with the heat sinks might be an isolator. Nice in that case the alternator was bad and you dont have to rely on psychic internet advice. Quote Link to comment Share on other sites More sharing options...
Bob C Posted January 2, 2013 Share Posted January 2, 2013 The blue finned object is your isolator. It looks like the one that was in my Escaper when I bought it. I replaced it when it would not pass voltage to the coach. Quote Link to comment Share on other sites More sharing options...
waiter Posted January 4, 2013 Share Posted January 4, 2013 The finned device in the photo is the isolator - If both batteries were discharged, and your sure the ignition was turned OFF, I would suspect the isolator is bad. Personally, I would replace it with one of the older style mechanical isolators Bad Alternator - Its possible that the alternator bad and the dead batteries are related, i.e. the bad alternator could have kept the isolar energized, causing both batteries to run down. TWANG - This is the self resetting circuit breaker popping and resetting. If the battery was real low, its possible it could be drawing a lot of current and cause the breaker to pop/reset. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
Totem Posted January 4, 2013 Share Posted January 4, 2013 LOL this exact situation happened to me, I had a post on it. Here is what happend: 1.) you have multiple problems that all came to a head 2.) your alternator is definately dead; pull it. this will involve removing the belt and two bolts holding the alternator one is a tensioner and one is the arm (the bigger) 3.) I wouldn't jump to assume that your isolator (the blue aluminum finned square thing in your picture) is bad just yet here is what I think based on what you told us: you drained coach battery over the span of 5 hours to the inverter. You drained (unknowingly) the cab battery just from driving with a bad alternator. thus they were both dead. The funny part to me is that you should have seen a couple red lights on your dash when your alternator died, like a brake light and one other one. they will light when the alternator output falls below a certain voltage. you will also note that headlights and radio etc will quickly drain a non charging battery. Since your genset charged both coach and cab I'd say your isolator is peachy aok. 4.) you are very lucky to have a generator; run it as a Poor mans alternator and turn off all non essential electrical and drive to nearest Nappa. Avoid autozone remanufactured alternators like the plague. Insist that they bench test the "new" alternator BEFORE you install it in the parking lot to save time on a dud. Good luck! Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 4, 2013 Author Share Posted January 4, 2013 Interesting - I woke up this morning (everything working) and drove about 15 miles to get to a spot where I can get an internet signal. When I set up my office to do some work I had no 12v system again and the banjo twang is back. I purchased a meter to get some amp and volt readings since they are obviously important to help figure out where my problems are. I'm not electrically savvy so please bare with me. I took readings on both batteries and they read the same 12.5 v each not running. Started the truck and now both batteries are dropping. The first time I had this problem the guy at the auto parts store tested the batteries and it was the same thing (both batteries read the same voltage like they are linked or paralleled). So now should I assume the isolator is bad? I tried testing the isolator, but couldn't get a reading. I put the neg on the left black wire and the positive on the right and middle red wire, nothing. With the truck running and not running. Do you think I will need to replace the alternator again since it is not charging the batteries? Quote Link to comment Share on other sites More sharing options...
Totem Posted January 4, 2013 Share Posted January 4, 2013 put a probe on the alternator output post and ground while running. whats your reading? My money is still on dead alternator for sure. we can go from there. Quote Link to comment Share on other sites More sharing options...
zero Posted January 4, 2013 Share Posted January 4, 2013 I took readings on both batteries and they read the same 12.5 v each not running. 12.5 volts is 3/4 charged. You need to take your voltmeter and test voltage at the output terminmal on the alternator. Red lead to that terminal and black lead to a known good ground. It needs to be 13-14 volt range when the engine is running. It should read whatever battery voltage is when the engine is not running. If you only read battery voltage when the engine is running at that terminal - then the alternator is not working. Not sure if you have an internal or external regulator. If internal - it's time to yank the alternator and fix. The isolator box takes the power from that main terminal on the alternator and splits it in two - to charge both batteries. Simple isolators just split the current in half (if both batterie are same rate of charge) or sends the most current to the deadest battery. More complex isolators make sure the engine cranking battery gets priority and gets charged first. There is no "guess work" here since you have a volt-meter. Voltage at the alternator output terminal MUST be higher then your batteries or no charge can take place. Either it IS or it is ISN'T. On a side-note a faulty alternator under certain circumstances can also result in the "no charge" light not coming on to warn you. Doesn't seem quite fair. Quote Link to comment Share on other sites More sharing options...
zero Posted January 4, 2013 Share Posted January 4, 2013 . .both batteries read the same voltage like they are linked or paralleled Both batteries are in essence "paralleled" when the engine is running and the alternator is charging. That because alternator voltage always exceeds battery voltage to a slight degree so both batteries will basically be just a hair below alternator voltage. When the engine is off - both batteries are supposed to be totally separated. If not - your isolator is bad or mis-wired. Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 4, 2013 Author Share Posted January 4, 2013 The alternator tested ok at the shop, but when its in the truck I'm getting some strange readings. Not running Truck bat 12.4, house bat 12.4 Isolator -12.4 Running Truck bat 11.5, house bat 11.9 Isolator -11.9, Alternator 0.25 Quote Link to comment Share on other sites More sharing options...
Totem Posted January 5, 2013 Share Posted January 5, 2013 Red lights on on dash at all? Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 5, 2013 Share Posted January 5, 2013 You have a external regulator I believe it to be a solid state regulator it's on/off state is controlled by a 15 amp fuse I believe it is the "engine" fuse and again I think the color is red. It will be the "ign lead on the regulator if it has no voltage with the key on it won't charge. You voltages represents system current draw of a non charging alternator. Posts 1 and 2 on the isolator should have battery voltage all the time key on or off. The "A" terminal should be zilch with out the engine running if it's not it still should charge but it will not work as an isolator. Once the alternator is charging the "A" terminal will represent charging voltage and terminals 1 and 2 should show rising voltage. If any one asks your system does not require a "E" terminal on the isolator internally regulated alternators do. If the alternator checks good and you have voltage at the "ign" terminal on the regulator you'll need to have a serious look at the regulator. Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 5, 2013 Author Share Posted January 5, 2013 If the alternator checks good and you have voltage at the "ign" terminal on the regulator you'll need to have a serious look at the regulator. Since the alternator tested good once it was out of the truck (not the problem) I now need to identify where my regulator is. Is that the gold looking box in my picture? Bye the way, just like the first time this happened I ran the generator for a few hours last night, ran the truck about 20 miles this morning and now I have 12 v power again and no banjo twang. It's obvious that there is an issue when I drain the battery down more than 1/2 way, but what could be causing the problem? Isolator, regulator, wiring, all of these? Batteries read: Not running Truck bat 13.1, house bat 13.4 Isolator .05 Quote Link to comment Share on other sites More sharing options...
zero Posted January 5, 2013 Share Posted January 5, 2013 Since the alternator tested good once it was out of the truck (not the problem) I now need to identify where my regulator is. Is that the gold looking box in my picture? Bye the way, just like the first time this happened I ran the generator for a few hours last night, ran the truck about 20 miles this morning and now I have 12 v power again and no banjo twang. It's obvious that there is an issue when I drain the battery down more than 1/2 way, but what could be causing the problem? Isolator, regulator, wiring, all of these? Batteries read: Not running Truck bat 13.1, house bat 13.4 Isolator .05 Neither of your batteries can be more then 12.7 volts (fully charged). Either your voltmeter is wrong or you are checking too soon after charging. A battery must sit at least 15 minutes with no charging before you can check voltage. One fully charged cell is 2.11 volts and your batteries have six cells each. When a battery is charged each cell can reach 2.2 volts (13.2 volts for a 12 volt battery) but that is temporary and settles down to true battery voltage in a few mintues. In the photo you posted, the regulator is the metal box on the right that is held to the truck by two bolts. It has a wire-harness with a plastic connector at the end with five connections inside. The five connectors go to: field in alternator, batt neg, batt pos from ignition, stator in alternator, and charge light on dashboard, You can buy a new regulator for $11 if you shop around. Many parts places are unloading them cheap since these trucks are considered "obsolete" by many parts sellers. http://www.rockauto.com/catalog/x,carcode,1277197,parttype,4884 Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 5, 2013 Share Posted January 5, 2013 If you have voltage on the red wire with the key on at the regulator most likely the regulator is toes up you should also see voltage on the white wire key on. The black box next to your isolator is the regulator. 13 volts is normal for a freshly charged battery.You may have more then one issue but it will have to charge before you can move on. The thing that bothers me is running your generator to charge the batteries. The coach battery will charge, the truck battery will not with that set up. So if the truck battery is up to snuff the alternator is doing some thing it kind of sounds like the regulator is intermittent if you can buy one for $11 I would just replace it. The fact you were showing no voltage at the " A" terminal pretty much rules out the isolator. Quote Link to comment Share on other sites More sharing options...
zero Posted January 6, 2013 Share Posted January 6, 2013 Since the alternator tested good once it was out of the truck (not the problem) I now need to identify where my regulator is. Is that the gold looking box in my picture? Do the checks in this chart and tell us what you get. Quote Link to comment Share on other sites More sharing options...
5Toyota Posted January 6, 2013 Share Posted January 6, 2013 in that picture i see what looks too be several heavy rusted connections looks to be a curkit breaker from looks of that i would replace that and clean sand or file those rusted terminals replace voltage reg could even be all rusted up inside seen that before even when they are supposdly sealed. Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 6, 2013 Share Posted January 6, 2013 There is zero magic inside of the isolator it is a simple dumb box with either 2 or 3 diodes inside depending on the alternator type. A diode is a one way gate it only allows current to flow in one direction. This is how the isolator keeps the power flow between the batteries from interacting while allowing the batteries to charge. As you can see the two batteries are connected at the “A” terminal but the diode will not allow them to electrically join but will allow current to flow to both batteries from the “A” terminal. A diode of that type requires .7 volts of a volt to break over and conduct this loss of power this is why the box has cooling fins the diodes get hot. It does not regulate make coffee or care what the batteries are it just blocks current flow in one direction. Terminals 1 and 2 are battery connections the “A“ terminal goes directly to the alternator “B” terminal 1 and two can be interchanged it does not matter what battery is connected to them but it does make it easier for you if you know which one is what. The internal regulated alternator requires a 3rd diode (the “E” terminal) to excite the alternator it goes back to the keyed on electrics of the truck. Without 12 volts at the alternator “B” terminal it will not charge. A externally regulated alternator does not require the "E" terminal. Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 7, 2013 Author Share Posted January 7, 2013 Do the checks in this chart and tell us what you get. I clean up the rusty connections yesterday and replaced the two 30a fuses. These are the readings I got this morning. Not running A/B .07, E/G 12.5, C/D 12.5 Running A/B reading all over the place from .5 to 9.8, E/G 18.5, C/D 17.5 Quote Link to comment Share on other sites More sharing options...
83 SunRader Posted January 7, 2013 Author Share Posted January 7, 2013 If you have voltage on the red wire with the key on at the regulator most likely the regulator is toes up you should also see voltage on the white wire key on. The black box next to your isolator is the regulator. 13 volts is normal for a freshly charged battery.You may have more then one issue but it will have to charge before you can move on. The thing that bothers me is running your generator to charge the batteries. The coach battery will charge, the truck battery will not with that set up. So if the truck battery is up to snuff the alternator is doing some thing it kind of sounds like the regulator is intermittent if you can buy one for $11 I would just replace it. The fact you were showing no voltage at the " A" terminal pretty much rules out the isolator. I show voltage at both the red and white (regulator) wires and the voltage reads the same as the truck battery voltage. Quote Link to comment Share on other sites More sharing options...
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