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loving retirement
SF Bay Area
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Joined: 06/30/2006
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Seems that the isolator that prevents the engine battery from being drained by the coach battery(s) on B's for decades is being replaced on some (maybe all, I do not know) B's by a new device, the "separator."
Anyone know the advantages, and disadvantages of the separator over an isolator?
Anyone replaced their isolator with a separator on their B and why?
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landyacht318
Near a large body of water
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Joined: 07/11/2007
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Excellent question. One I wish I knew a definite answer to.
The isolator solenoid connects the batteries when it sees 12 volts from a switched source. The isolator solenoid pulls some amperage just to keep the contacts engaged. I think up to 1.5 amps. Amps that could be sent into the batteries instead. I have also read how the contacts inside can burn out over time and keep the house battery from seeing alternator amperage. Apparently the quality of these solenoids varies greatly.
Depending on the source of the switched 12 volts, the solenoid could be starting the vehicle with all the batteries. Not usually an issue, but once when I had a newly rebuilt alternator and before I had solar, I started my van with 3 depleted batteries. Either the unbroken in brushes glazed over under the stress, or got temporarily blown off the armature leaving me without a charging system while far from any town, south of the border.
I think a separator is a diode allowing electricity to only flow in one direction.
Perhaps it has some circuitry to only connect the two batteries when it sees charging voltages. Maybe they have their own DC to DC converter stepping up the voltage to the house battery to insure a full charge is possible.
I know most simple isolator/ separator diodes drop the voltage flowing through them and that can lead to chronic undercharging of the isolated/ separated battery.
I have opted for the manual switch, which has the detraction of not being automatic, but does not cause significant voltage drop.
It also has the ability to be an alternator destroyer if someone turns the switch to off while the engine is running. I know some people like to claim this procedure(disconnecting the battery with engine running) is a good test to see if the alternator is working properly, but every alternator website out there says not to do this.
I enjoy being able to start the van on the isolated engine battery(1) and watching my battery monitor for the alternator amps, then after it settles down, switching to BOTH and then hearing the note of the engine change as the amperage goes from about 12 to 40+ amps(temporarily) depending on the SOC of the house batteries(2).
It also works nicely as a battery disconnect for the chassis system. I have most of the house systems wired directly to the House battery terminal so they are still operational with the switch off. I could change this, but with solar, I don't worry about needing a house battery disconnect. I could just pull the fuses if I needed to.
I've read how 25 alternator charging amps requires 1 HP from the engine.
This thread might get a lot of more qualified answers over in the Tech issues forum.
On edit: After a little research I have found some solenoids are called separators, some are called isolators. Some have additional logic circuitry added so they only connect at voltages above 13.2. All the Solenoids appear roundish. There are the other type of separators/ isolators that are squarish with visible heat sink type fins. I have no knowledge on how these operate.
* This post was
edited 03/07/10 12:37am by landyacht318 *
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pianotuna
Regina, SK, Canada
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Hi landyacht318,
It is too bad the OP did not give a url for the "battery separator". I agree that a simple diode may often be a route to chronic under charging.
You could easily modify the manual switch so that it would not be an alternator destroyer.
snip
I have opted for the manual switch, which has the detraction of not being automatic, but does not cause significant voltage drop.
It also has the ability to be an alternator destroyer if someone turns the switch to off while the engine is running. I know some people like to claim this procedure(disconnecting the battery with engine running) is a good test to see if the alternator is working properly, but every alternator website out there says not to do this.
I enjoy being able to start the van on the isolated engine battery(1) and watching my battery monitor for the alternator amps, then after it settles down, switching to BOTH and then hearing the note of the engine change as the amperage goes from about 12 to 40+ amps(temporarily) depending on the SOC of the house batteries(2).
It also works nicely as a battery disconnect for the chassis system. I have most of the house systems wired directly to the House battery terminal so they are still operational with the switch off. I could change this, but with solar, I don't worry about needing a house battery disconnect. I could just pull the fuses if I needed to.
I've read how 25 alternator charging amps requires 1 HP from the engine.
This thread might get a lot of more qualified answers over in the Tech issues forum.
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
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landyacht318
Near a large body of water
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pianotuna wrote:
You could easily modify the manual switch so that it would not be an alternator destroyer.
Yeah, my manual switch has the ability to route the field wires of the alternator through the switch instead of directly from the voltage regulator to the alternator. This would disconnect the field and essentially turn off the alternator if the switch were turned to off. Protecting the alternator and any sensitive electronics.
This would be good idiot proof insurance, but since I don't allow anyone else inside my electrical cabinet, I have not made the Modification. This modification would also add about 18 feet of additional wiring from the ECM and it's internal VR to the Switch and back to the Alternator. I fear this might lower the ultimate output of the Alternator unless I used some real heavy wire.
I brought it up to inform others of the possibility of alternator and/or other electronic damage when turning the manual switch to OFF while the engine is running, or the foolishness of disconnecting a battery of a running engine to check the alternator. This might have been okay on the lower output alternators of the pre '85 pre electronic era vehicles, but not today's vehicles.
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pianotuna
Regina, SK, Canada
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Hi Landyacht318,
I am still very curious to know exactly what the "separator" is that the OP has alluded to.
That's a very elegant solution to alternator protection--but my idea was much more low tech.
I feed one of my battery banks from the starter battery via a manually controlled relay fused at 60 amps (a manual switch would have worked just as well), which draws from the alternator, so the alternator is never without a load. If the battery bank is down when I switch it in that causes the alternator to work a bit harder.
The original bank is charged directly from the alternator (I think--not sure about that) via a second manually controlled relay fused at 60 amps.
I don't have to worry about the fuses blowing nor the contacts burning because the relays are opened when the key is turned to the start position. It has a side benefit of a "poor man's" boost. If the starter battery happens to be down, I can turn on the key...and wait 15 minutes for the house batteries to back feed to the starter battery.
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landyacht318
Near a large body of water
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PT, I think it is bad for the ignition coil for the key to be switched to run(not start) for any extended time. I have witnessed a coil die on a 80's land cruiser when the owner turned the key to run, just to listen to the stereo.
I think the OP was more interested in fully automatic battery isolators, neither of which we have.
Perhaps I misunderstood but your description, but it sounds like you have a manually operated relay between the alternator and starting battery, which could leave you vulnerable to damaging the diodes in the alternator, if it were switched off. I don't think I would be happy with only 60 amp fusing either. Even my under wired 130 amp alternator can output more than that, briefly. If your fuse blows, then so might the alternator.
I think if I were to build a fully automatic dual battery system, I would go with this product.
National Luna Intelligent soleniod.
Which is designed to work with these battery monitors:
National Luna Dual monitor/controller
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landyacht318
Near a large body of water
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I was just reading over at a 4x4 forum and came across this post by someone who thoughtfully described most all the ways and methods products of battery isolation.
Lots of good info, well summarized. Should cover the OP's question.
"There are 5 types of battery management systems that i count...
1. a manual high-current switch with A/B/BOTH selectors (a "boat switch")
- there are no "smarts" to the system, it only does exactly what you tell it, this can be good and bad (good that you have full control, but bad as you could leave it set to "both" and leave something on thereby depleting both batteries and having no backup)
- when in "both" mode, the batteries are not isolated in any way, i.e. if one is a different physical type that rests at a lower voltage, it will always be trying to discharge the higher resting voltage one
- good in the fact that you wouldn't have to remove a completely shorted battery physically from the system. i.e. you could just set the switch to "B" if "A" had completely shorted out.
- doesn't work well remotely... i.e. you need to mount the switch near the batteries or else you are going to have to run 3 cables of some very large gauge wire all the way to wherever the switch is (i've seen it done, but not practical for most people)
2. a "boat switch" and a battery isolator (such as from sure power or perfect switch)
- all the same characteristics as just a "boat switch" but without the worry of one battery "bleeding" the other, the batteries are isolated in that only charge current goes to both of them, but no current transfers between them
- i my opinion this would always be the way to go in a completely manual system, you wouldn't want to just go with the boat switch when you can pickup and isolator to use with it for pretty cheap
3. an intelligently controlled solenoid system (national luna or IBS for example)
- in this case a solenoid (high current relay) acts as the "boat switch", except in all systems i know of, you only have "A" and "BOTH" settings. the big plus is that you run a small cable to a remote controller to set the state of the solenoid instead of having to run giant cable in order to relocate the "boat" switch (and the solenoid stays near the batteries).
- the intelligence is in the form of a small microcontroller that can monitor either ignition state and/or time and/or each battery's voltage, and based on that information set the solenoid switch to "A" or "BOTH"
- - when i say monitor ignition-state/time/voltage, it depends on the system. some merely tie the batteries in parallel (i.e. the "BOTH" setting) when the car is running and for a few moments after the car has been shut off, then it sets everything back to the main battery (i.e. the "A" setting). other systems may be smarter and actually look at each batteries voltage and the incoming voltage and sense that it's ok to tie them together when there's a supply voltage (i.e. the car is on) and then sense that if for any reason one of them starts to loose voltage (bad battery, whatever), it shuts off feed to that battery.
- ussually these systems have an override so that when you want to, you can manually set the batteries in parallel (the "BOTH" setting) for winching power or for starting from the backup ("B") battery.
- the only downside compared to the "boat switch" + isolator method is that in most systems you only have the "A" and "BOTH" setting, you have no pure "B" setting... i.e. if your "A" battery actually shorts out, then you will have to physically remove it from the system... you wouldn't want to switch to "BOTH" in that scenario. now if your "A" battery is just low (more typical situation), then you can safely switch to "BOTH" in order to start the car still.
- these manufactures will tell you a solenoid (high current relay) is tried and true simple switch that is less prone to failure than fancy digital switches
- national luna and IBS both offer fancy remote controllers with voltage monitors for both batteries, audible alarms, etc.
- IBS's "BOTH" setting is timer based so you can't easily leave them connected for too long. national luna's "BOTH" setting has a warning light to show you it is engaged.
- IBS's system handles 500 amps (200 continuous) whereas national luna is rated at 400 amps (85 continuous). note the continous rating is very different, might matter for when you want to tie both batteries together for a large winch.
- IBS and National Luna are about the same price, and i hear that Etreme Outback is carrying the IBS system even though their site doesn't show it yet (according to winter overland journal).
4. in intelligently controlled digital switch (hellroaring for example)
- pretty much the same as the intelligently controlled solenoid except that the solenoid is replaced my a modern digital switch
- these manufactures will tell you a digital switch is supposedly better technology than a solenoid which can get contacts stuck, worn, corroded, or filmed (opposite of what the solenoid people say, i tend to believe that modern solid state electronics are better than traditional high current relays, but this is personal opinion).
- hellroaring uses the voltage monitoring method of intelligent control instead of just a timer and ignition switch check.. i.e. if you alternator fails then it will sense the non input voltage and isolate your backup battery so that you aren't draining them both. a lesser system might just know that the car was runnign and therefore assume it was safe to tie the batteries together for charge when in reality it would be letting them both run dead.
- hellroaring has a remote switch module that lets you put the system in "A", Automatic, or "BOTH" but doesn not have fancy voltage monitors (you could add these yourself for cheap). it also does not have a timer circuit (so you are more likely to accidentally leave it set to "BOTH" and then potentially run both batteries down).
- hellroaring handles 500 amps (150 continuous)
- hellroaring is a fair bit less expensive than national luna or IBS, but doesn't offer nearly as fancy of controller interface
5. some "i did it this way" method that use pieces from the above types of systems
- i guess the ultimate system would be to use 2 digital switches (probably from perfect switch, as they supposedly have the best digital switch) and your own custom microcontroller that would allow you to have all the system sensing and control qualities of national luna/IBS/hellroaring products, but with a "B" setting too (instead of just "A" and "BOTH"). add to that your own digital voltage readouts of both batteries and custom control panel with override switches and timers and audible alarms.
the above would be $$$ and room for errors since it's a custom system instead of a tried and true system tested by thousands of users.
more reading:
http://www.nationalluna.com/DIY.htm
http://www.hellroaring.com
http://ibs-tech.ch/en/products/dual-...ith-uproc.html
http://www.surepower.com
http://www.bluesea.com
http://www.perfectswitch.com/power-g...ge-controllers
For the full thread, if that was not enough reading for you:
http://expeditionportal.com/forum/showthread.php?t=35667&page=2
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pianotuna
Regina, SK, Canada
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Hi landyacht318,
Nice post on the "five" methods. I sure would not like the hellfire--if my alternator did happen to fail, I want as much battery as possible to "get me home".
>PT, I think it is bad for the ignition coil for the key to be >switched to run(not start) for any extended time. I have witnessed >a coil die on a 80's land cruiser when the owner turned the key to >run, just to listen to the stereo.
I don't expect to use that feature--but it remains there "in a pinch". I've not checked to see if the relays are operative on the aux setting of the ignition switch. I keep forgetting to do so.
>I think the OP was more interested in fully automatic battery >isolators, neither of which we have.
agreed
>Perhaps I misunderstood but your description, but it sounds like you >have a manually operated relay between the alternator and starting >battery, which could leave you vulnerable to damaging the diodes in >the alternator, if it were switched off.
Yes, you did. There is no fuse or relay between the original starter battery and the alternator, therefore there is always something for the alternator to "see".
>I don't think I would be happy with only 60 amp fusing either. Even >my under wired 130 amp alternator can output more than that, >briefly. If your fuse blows, then so might the alternator.
Nope. The fuse is there to protect the wire down stream from the relay. Relays are rated at 100 amps continuous and 1000 amps momentary (I think--been too long now and I failed to write it down).
>I think if I were to build a fully automatic dual battery system, I >would go with this product.
>National Luna Intelligent soleniod.
I don't prefer automatic in general.
>Which is designed to work with these battery monitors:
>National Luna Dual monitor/controller
I don't think that I want more than a decent volt meter for monitoring, but those look nice. I'd really rather spend my money on more solar than on a gauge to tell me I need more solar LOL
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RJsfishin
Winston Or.
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Joined: 10/16/2007
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Quite simple,....
Diodes isolators suck, get rid of it.
And I can't believe we would even be talking about perko switches, chuck that idea,
A seperator can be anything that physically seperates the 2 banks of batteries.
There are $20 ones (constant duty solenoids) and there are $100+ ones, like Intellec.
For simplicity of hookup and least expense, the $20 constant duty solenoids work just great. I have had one fail in 30 years, and even if that happens it simple to tempory fix it,....just connect a jumper from one big post to the other, and all batteries charge.
If we're worries about the 1-2 amps to power it, then I give up 
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat.
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pianotuna
Regina, SK, Canada
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Hi Rich,
I agree--Kiss may often be better. But we still don't know what the OP was referring to--and it might be fascinating.
My original RV did have a diode and it did fail. I had no idea that it had until there were serious electrical problems elsewhere. A tiny teeny solar system (by today's standards) had kept the house batteries in good shape.
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