:-\ Moving from a campground down the highway, and the Heart Freedom starts blinking and the SeeLevel gauge indicates that the house bank is 17 volts! Turn the inverter off and kill the engine. Voltage drops to normal range, but house bank bay smells like sulfur. Start it up, House bank goes back up to 17 volts. Chassis battery seems normal according to VMSPC. Popped the bed, and it the isolated looks like the cable on curb side of the isolator has been very hot. So what to do? Can I bypass the isolator with a switch or disconnect the house bank from it without destroying something? I just want to get it back home base where I can work on it with access to my stuff... Just turning the inverter off didn't help anything. Is it the alternator that may have failed and is putting out to many volts? I am not think that clearly at the moment, so any objective input would be appreciated!
Don
We had that same problem in 06 and turned out to be the voltage regulator on the alternator. easy fix with the right part. :(
Do not rely on readouts from the Displays. Use your multimeter to make sure of these voltages before you go nuts looking for something that is not there.
Don,
Yes, you can bypass the isolator so that the chassis battery is charged, but house is not.
But, first thing I would do is separate the house batteries and see if there is one bad battery that you can just take out of the circuit.
If not successful, remove the center wire on the isolator (from alternator) and nut it to the chassis battery lug of the isolator.
But, I am a little puzzled. The sense wire for the alternator is generally on the chassis battery lug of the isolator, so a bad house battery should not trigger out of spec voltage.
I did check with a meter and it agrees with the SeeLevel... Just did another test. With the generator running, but not the engine, the Inverter appears to be charging the house battery normally. Generator off, start the engine, and for about 60 seconds, everything seems normal. Then, the lights on the inverter go crazy, and the house bank is showing 17 and the chassis shows normal. This was verified at the batteries. Now the question is, how can I disconnect the house bank from the alternator/isolator combo without frying something?
Don
Don, Why can't you just turn the inverter off and disconnect the house batteries to get you home ?
Gary B
I did separate the two house batteries from each other and they appeared to be the same voltage. Unfortunately, I apparently fried my SeeLevel tank gauges when I reconnected the house bank... should have used the disconnect switch, duh! Ironically, the voltage portion of the SeeLevel gage still works. Oh well, live and learn or die trying! Oddly enough, the curbside cable (the melted looking one) on the Isolator corresponds to the chassis battery voltage, and the the street side corresponds to the house bank. the plastic strip along the top of the isolator appears to be somewhat melted as well... but I am not sure if that is new or not.
Don
I will certainly do that if that doesn't screw something else up. Unfortunately, this is one area of coach lore that I haven't explored yet, though it is on my list... :o
Don
Don, sounds like your alternator has gone haywire. I'm afraid you run the risk of ruining your chassis batteries also. Might consider completely disconnecting alternator and using the genset to make it home.
See my first post for how to isolate the house battery bank-- actually, just direct connecting alternator output to chassis battery lug of isolator. If you recall, I basically did this on our U240 permanently: Alternator output, sense wire and chassis battery to one lug of marine ON-OFF switch. House battery cable to the other lug. With switch off, alternator charges only chassis battery. With switch on, both banks charged.
But, you also want to make sure that the sense wire is in good shape, as that is the wire that "regulates" the voltage.
Thanks Brett! I had already done as you suggested... just had tried it yet. I started by disconnecting the house bank, and starting the engine... Chassis battery showing normal charging voltage. Reconnected the house bank and it is showing battery voltage. So, my best guess is that the isolator has taken a shortcut to heaven... bloody coward. I just needed it to go another 200 miles. Thanks for your help! On the road again, will update when we make home!
Don
Don, time to put in a Sterling unit.!!!
I have not done it yet as been busy-sort of with other things. Hopefully will get it in before heading south, if not will take it with us to do in the warmth.
JohnH
Bomb-proof solution-- wire as in my post above: PERKO Inc. - Catalog - Battery Switches - Heavy Duty Battery Disconnect Switch (http://www.perko.com/catalog/battery_switches/99/heavy_duty_battery_disconnect_switch/)
Other use: in CG with shore power this morning. In CG with shore power tonight. Why pay diesel to OVERcharge the house bank all day? Leave switch off.
Other use: Excellent/safe battery combiner for starting (rated 1200 amps intermittent).
Other use: Combine so that converter or inverter/charger charges BOTH battery banks with on shore power.
Easy to mount at the foot of the bed.
MANUAL IS SOMETIMES THE CORRECT KISS ANSWER.
brett,
Does the alternator regulator have to be adjusted to account for the increase in charging voltage after the isolator is removed?
Larry
Larry,
The sense wire is left in place. So, voltage at the chassis battery is exactly the same as before. The only difference is because the loss across the diode-based isolator (about .7 VDC) is eliminated, the alternator does not have to "over-produce" only to have some if its production turned into heat in the diode-based isolator. HEAT is why the diode-based isolator has all those aluminum fins-- to get rid of the heat.
Don,
Shortly after we bought our coach I had the same thing happen. It was a bad isolator. I installed a new 200A unit and it has been fine ever since.
Mark
So Brett. Does the Perko switch enable you to remove the isolater from the system ? I had those on my bus but never new what they did.
Yes, if wired: alternator B+/positive to one lug. Chassis battery cable to same lug. Sense wire to same lug.
House battery cable to other lug.
Just a slight variation on the way all our sailboats were wired-- and 90% of their use was "wet-camping" (w/o shore power and no generator).
Thanks Brett, Next project.
Don, I agree with all that Brett has offered.
Question, did you ever heed my advice and move your alternator sense wire off of the forward engine compartment bulkhead to the engine start battery bank (+) terminal posts? If you did not, it easily explains everything written in this thread (both this entry and all subsequent entries). Where is the far end of your alternator battery voltage sense wire landed?
See: http://www.foreforums.com/index.php?action=media;sa=album;in=170 (http://www.foreforums.com/index.php?action=media;sa=album;in=170)
Here are a few comments entered into your initial question:
Moving from a campground down the highway, and the Heart Freedom starts blinking and the SeeLevel gauge indicates that the house bank is 17 volts! That means the alternator lost good communication with BOTH battery (+)'s, and the alternator has failed to maximum output (17 Vdc), trying to increase the voltage at the far end of the sense wire.
Turn the inverter off and kill the engine. Voltage drops to normal range, but house bank bay smells like sulfur. That means the house batteries have been grossly overcharged. I assume that the engine start batteries were normal smell and their cases and cables were not warm or hot?
Start it up, House bank goes back up to 17 volts. Chassis battery seems normal according to VMSPC. Engine start battery would be the normal Vdc because the Isolator diode has been burned out (OPEN circuit path) and the engine has not discharged the start battery bank for long enough to significantly discharge the bank, even though it is not being charged.
Popped the bed, and it the isolated looks like the cable on curb side of the isolator has been very hot. I assume that the "curb side" is the start battery bank side cable and that that isolator diode has seen over voltage and is burned out (OPEN).
So what to do? At the isolator, tie the house battery bank cable, the start battery bank cable, the Alternator output cable and a temporary Alternator sense Jumper wire all together on the one good terminal of the isolator. If voltages (with the engine running) return to normal, you know what the problem is. The battery start bank sense wire (from the alternator to the start battery bank's (+) terminal, has partially or totally failed (opened or significantly increased in resistance, which drops voltage, which makes the alternator think the start battery bank is low, which causes the alternator to increase its output, which eventually goes to maximum, which is 17Vdc.). With the Alternator output going high (17 Vdc), it overcharges both battery banks until an isolator diode or a battery fails to an OPEN circuit condition (usually taking out things like your SeeLevel instruments along the way because, unless specifically designed to be protected, they cannot tolerate the 17Vdc continuously).
Can I bypass the isolator with a switch or disconnect the house bank from it without destroying something? I just want to get it back home base where I can work on it with access to my stuff... Just turning the inverter off didn't help anything. Is it the alternator that may have failed and is putting out to many volts? I am not think that clearly at the moment, so any objective input would be appreciated!
BTW, if I am right, there is nothing wrong with your alternator (it is doing only what it should be doing). The isolator is definitely toast and the "plastic strip" that you refer to is really a "brick" of diode potting compound that has been melted from overcurrent. No telling how much sympathy the house batteries have for all this. Are the sides bulged badly? The start batteries also saw abuse until the overcharging blew the isolator diode to that bank, so check for bulging there too.
Call if you have questions, 603-770-7459
Neal
Brett,
If you put a battery disconnect switch between the house battery bank and the battery isolator, then you would have the advantage of not charging the house bank unnecessarily. And, you would have the advantage of the battery isolator separating the batteries when they were not being charged.
You would of course still have the possibility of a battery isolator failure. But, I think the failure rate of the battery isolator would be fairly low and it is easy to wire around it in case of failure.
Larry
Thanks for all the suggestions... we made home a few minutes ago with no further drama from the charging system after bypassing the Isolator by putting the center post directly on the Chassis battery terminal on the Isolator as Brett suggested. According to VMSPC, the charging voltage was normal range all the way home. Too tired to respond more at the moment... except to say that I got a stop engine light three times on the way home that went away almost immediately two of the three times and within about 10 seconds the other time (that was a long 10 seconds!). The diagnostics page in VMSPC wasn't very helpful, and thus far I haven't been able to figure out what the fault codes correspond to. This also happened twice on the previous leg of our trip. Every time it has happened so far, it was going up hill under load. Coolant temperature staying around 182ยบ, Trans temperatures, oil pressure, et al. all within normal ranges. This was a Stop Engine light, not a check engine light... by the time I realized what the warning light was and was thinking about pulling over at the next possible spot, the light went away each time. Another head scratcher as if I haven't had my share... :-\
Well, hanging it up for tonight... back at it tomorrow. At least I am parked at my home base and can stay here long enough to get parts and figure out what is what. Neil, I will probably be taking you up on the phone call once I have had a chance to sleep and chew on this a bit... thanks for the offer. I will plan on rerouting the sense wire to the battery terminal as I decide what parts I need. I will definitely be changing how this system is hooked up. I had been planning on it all along, I just ran out of time before we had to leave for our 5 month trip to Canada.
Don
On my sailboat, I installed Blue Sea 7700 and 7622 relays so I could isolate batteries and busses both remotely and manually. I was considering doing the same to my 96 and I will likely do the same to my 2005.
Needless complexity. Install a manual battery switch or better yet tie everything together and don't worry about it. Just about to install three new red tops in my sister's coach because the battery maintainer failed. (long term storage, plugged into bulletproof service behind a progressive surge protector) Had they all been tied together and to the charger all would have been jake.
When you think about it, the isolator is for the owner who doesn't think much about battery levels, just wants to make sure it goes vroom when they want. Who among us doesn't monitor battery state when dry camping?
My guru buddy installed a non normally used outside battery equalizer. Much higher output than a trickl charger. 20 amps? Capacity.
If the house batteries are receiving a charge the chassis batteries get it also.
Brett wanted a picture or info a while ago. Mounted externally he sealed the adjustment holes with sealant.
Seems to work well as my small solar 130 watt panel keeps the house batteries charged and when I try the coach the engine cranks perfectiy after a month stored
For storage, just hook up a jumper wire with alligator clips. Use thin wire, or install a fuse.
Or just eliminate the whole isolator mess, use a standard, self excited alternator available anywhere instead of Duvac, lose the diode voltage drop, tie both battery banks together and enjoy a simple, durable electrical system.
Maybe I'm missing something here, but isn't the purpose of the isolator to separate the start batteries and the house batteries while camping? If all the batteries are tied together all the time what do you do when you run the batteries down to where you can't start either the generator or the big engine? On my coach, the house batteries start the generator as well as supply the house. The engine batteries start the engine. If I run the house batteries down to where I can't start the generator I can still start the Detroit, and the alternator charges both sets of batteries. If the start batteries are too low to start the Detroit I can start the generator or use the boost switch to start the engine. If all are tied together I'd be stuck.
David,
Plan "B" using the KISS theory for alternator yet maintaining isolation if the batteries while dry camping:
Buy a Perko ON-OFF switch: PERKO Inc. - Catalog - Battery Switches - Medium Duty Battery Disconnect Switch (http://www.perko.com/catalog/category/battery_switches/product/150/)
Wire alternator output (B+) and chassis battery cable to one lug.
Wire house battery cable to the other lug.
Either put the sense wire on the chassis battery terminal or to the B+ terminal of the alternator.
The 7622 in my boat setup is a bistable automatic charging relay. It disconnects when batteries are discharging and connects when they are charging.
Absolutely right. That's the reason for the isolator, the Duvac alternator, the sense circuit from isolator to alternator, and the need for an additional trickle charger between battery banks (to keep the chassis batteries charged during extended park sessions while unmaintained). That said, it would be extremely rare to find a forum member who doesn't keep an eye on battery charge while dry camped. Everyone knows to limit house bank discharge to less than 50% in order to preserve the expensive coach battery bank life. At that point, it's time for some shore power, generator power, alternator power or solar power to recharge. The whole additional layer of complexity and inefficiency is simply to compensate for blissfully ignorant management of battery banks. For the reasonably capable owner, though, it's a solution for a problem that does not exist. It also introduces additonal points of mechanical failure previously referenced.
A backup solution for someone who is worried about draining both banks would be to carry a small boost pack to fire up the genset. Or, as Brett suggested, install a mechanical battery selector switch, common marine item.
Mine seems to work well as it was installed from the factory, no re engineering needed. I simply do a little preventive maintenance, and inspection with a good meter once and a while and clean a terminal or 2 every year, keeps me from running out of something to do on the coach(ha).
Mine hasn't been any particular problem either though I have maintained it and if I were going to retain the system would relocate under the bed. One other thing you could eliminate in addition would be the boost switch and solenoid, no longer necessary if banks are tied together. Actually, Steve D's battery charger relay looks pretty intriguing, hadn't noticed it before posting. Noting the warranty on the item it's either absolutely bulletproof or very failure prone!
It has been proven to me without a doubt, though, that the present system puts an expensive bank of chassis batteries at risk depending on lifespan of a $50.00 trik-l-start or similar, and they seem to be pretty sketchy based on peoples comments of replacing them repeatedly. Cost my sister three new red tops to replace fairly new red tops and me some embarrassment explaining why she needed them. Her computerized engine apparently has significantly more draw on chassis batteries when parked than mine.
But many ways to skin this cat for sure.
After removing the isolator, boost solenoid, etc. One could:
(1) Increase the size of the house bank and remove the chassis bank
(2) Install manual transfer switches for shore power, generator and inverter/charger
Larry
If you eliminate the isolator panel (and its associated 0.6vdc voltage drop) make sure you adjust your alternator downwards so you don't fry those expensive batteries. Or install a smart charger for the alternator side of things.
Our old U225 has two house batteries (8D) and one start battery (2 redtops in parallel). I am replacing my two 8Ds with new wet cells simply because I want to wait and see how the Lithium batteries shake out and when we start snow-bording in 3 years we'll have a better idea of which way to go.
The downside to connecting all the batteries in the system together is, of course, the issue of running the bank down to where nothing will start. Solar mitigates this issue to a certain extent; provided that one is in a spot where the solar system will work and also in a place where you can stay long enough for it to charge the system up to the point where you can get going.
Some time ago I ran across a review of a small lithium battery pack that was able to charge numerous Jeeps out on a 4-wheeling weekend. The batteries for people seriously into 4-wheeling with their Jeeps can take a beating what with air compressors that air up huge tires, run the differential lockers, etc. and it's not uncommon for them to have dead batteries. The editors of JP magazine swear that they used this little battery pack to start 4 or 5 dead Jeeps and were looking for more; they just ran out of dead Jeep batteries.
http://antigravitybatteries.com/microstart/ (http://antigravitybatteries.com/microstart/)
I bought the XP-1 from Amazon and we carry it with us any time we drive farther than 35 miles in any vehicle. I haven't had to use it yet but with a 400-amp peak power capability I suspect it can start the 5.9 Cummins. After all, regular car batteries do that job in my pickup. At the very least it should easily start the generator.
http://www.amazon.com/Antigravity-Batteries-639713373219-Battery-Booster/dp/B00I9HGMYO/ref=sr_1_5?ie=UTF8&qid=1418833406&sr=8-5&keywords=antigravity+battery (http://www.amazon.com/Antigravity-Batteries-639713373219-Battery-Booster/dp/B00I9HGMYO/ref=sr_1_5?ie=UTF8&qid=1418833406&sr=8-5&keywords=antigravity+battery)
Holds a charge for a long time but I plug it into AC when we're home and into the solar system when we're out in the coach. I wait 'til the house batts are fully charged before I plug it into the coach's system.
I should probably test it. I think I'll wait for warmer weather.
Craig
This is an interesting discussion. I have just installed a trik-l start on my 1999 U320. The wires connected to my isolator are one from the house batteries to the house battery lug, one from the chassis batteries to the chassis battery lug and one to the center lug which I assume goes to the alternator. Mine looks just like the pictures in the Barry Beam description except there is no second wire on the chassis battery lug on the isolator. There are no additional wires to any of the lugs. Everything has worked well since I got the MH in 2009. Are there alternative wirings that I should be aware of?
Richard Anderson
1999 U320 40' build 5586
Craig,
Because of the external sense wire, no modification of the alternator is needed.
Said another way, the sense wire is on the chassis battery side of the isolator, so it reads voltage after the drop in the isolator. If no drop, it will automatically not OVER volt from the alternator, but keep the battery at the exact same readings.
In fact one could take the sense wire off the chassis battery terminal and put it on the B+ terminal of the alternator (as many, many alternators are already wired).
I