switching from battery isolator to battery separator problems

[kerryb]

Just had my lucas 70 amp alternator repaired and found my 100 amp isolator was also bad. Shop owner said alternator was not designed to work with isolator and talked me into a sure-power 100 amp separator. I tried to connect using present setup, ie just connecting the wire from alternator to the main post on the separator. When I leave the negative switch in the on position, it drains the battery. I switched the main battery and the aux. battery cables and it drained the aux bank. I don't think I had this problem when using the isolator. sure power tech. was unable to help as he sent a diagram basically eliminating the battery switches which is really not possible. Should I be able to use the separator with my setup? If so, am I doing something wrong in the connections? Why would having the positive alternator connected to the separator cause the battery(s) to discharge?
Thanks for any help,

Kerry

 

[Don S/V ILLusion]

Unless this is one of those local jargon things, it sounds to me like your local shop owner is using the wrong terminology which might indicate he doesn't know what he is talking about.
The only context in which I am familiar when discussing battery separator technology is in the fundamental construction of the battery itself.

More to the point, eliminating the isolator is a good move in favor of something either mechanical (e.g., relay) or a combiner, neither of which would cause the problem(s) you described.
Rather than get into a debate over semantics, if you can provide a wiring diagram, we can walk you through the problem.

 

[kerryb]

Unless this is one of those local jargon things, it sounds to me like your local shop owner is using the wrong terminology which might indicate he doesn't know what he is talking about.
The only context in which I am familiar when discussing battery separator technology is in the fundamental construction of the battery itself.

More to the point, eliminating the isolator is a good move in favor of something either mechanical (e.g., relay) or a combiner, neither of which would cause the problem(s) you described.
Rather than get into a debate over semantics, if you can provide a wiring diagram, we can walk you through the problem.

OK, here is the best I can do from memory on how it is setup. The MX....pdf file. Separator instructions to big to upload. Will try to find link and send.

 

[kerryb]

OK, here is the best I can do from memory on how it is setup. The MX....pdf file. Separator instructions to big to upload. Will try to find link and send.

The instructions is here:

http://www.surepower.com/bulletins.html

Firts pdf in the separator section.

 

[Rick Sylvester]

In a nutshell,

you've got the separator (most of us know it as a combiner) in the wrong circuit. If I understand your drawing (I'm not sure I get your switches) the separator is between the battery and the load. The separator should be separating the batteries.

There's any number of ways to do this but I would run circuits between the batteries and the switches normally so that they don't both see a load unless you want it. I'd then put the separator between the positives of the two banks. With a charging source running to one of the batteries the separator will connect that circuit only when it senses a voltage of 13.3 or higher. It will then disconnect that circuit when the voltage falls below that threshold so that the batteries can't be inadvertently and simultaneously discharged.

If my explanation still has you scratching your head you can refer to the Surepower link you provided. Their PDF provides a nice schematic and directions.

Why it's still discharging as you have it wired I don't know. It should be disconnecting your load before that happens so maybe you've got other issues. For sure it's doing you no good now.

 

[kerryb]

Don, the separator is like a selonoid switch from what I understand.

 

[kerryb]

oops! "solenoid"

 

[kerryb]

Rick, Thanks for the reply. I tried following the instructions, but what is throwing me, and the people from sure power, is the switches. Their tech department sent me a diagram, basically eliminating the switches as unnecessary, but that is not the case. I am almost thinking that I have another problem as well. I may pick up another isolator and put it back in the circuit to see if that solves it. It was working fine until the alternator stopped. I am also thinking I may have took a hit with lightening as I am working through the instruments one by one getting them repaired. I am just not sure what to look for outside of a cable that might be bad.

 

[Don S/V ILLusion]

Kerry
Rick summed it up well and I too saw the schematic on the mfg web site which should be helpful to you. Think of it as a relay used to temporarily connect batteries for charging purposes and disconnecting them to preclude the common problem of inevitably forgetting to switch them required with a manual switch.

You might want to refer to the mfg diagram and start over rather than trying to make your existing wiring conform to it.

 

[kerryb]

One last question before I dive into it tomorrow. If I move the alternator cable to the battery side of the main battery switch, and it discharges the main battery, what should I look for as the cause? I have the devise totally disconnected from the circuit now, and have the battery switches in the on position. I am pretty sure the batteries will be up when I go to the boat, which leaves the cable from the alternator as the suspect area.

 

[Rick Sylvester]

If the tech guy says to eliminate the switches

then he is an idiot. There are so many reasons NOT to follow this advice that I won't even get into it here.

I also wouldn't bother putting an isolator back in between the battery and the load. That's not what it's designed for and frankly, the combiner/relay (whatever you want to call it) is a far superior solution provided it's placed in the correct circuit.

I agree with Don (he must be a pretty smart guy ) in that it might be best to rebuild the whole shebang. That way you'll know how it's put together in case you have any problems or wish to make modifications in the future. If you "just get it to work again" you're going to continue to play guessing games. That's what I did. I ended up with one On-Off switch (no Both) for the start circuit, another On-Off switch for the house bank. I put a combiner in-between the banks. It's dead-nuts simple so that even an idiot like me can get his brain around it.

I agree that your alternator circuit needs some investigating. No way should it be discharging your batteries. There could be a partial short within the alternator itself but I'm sure there are many other possible reasons. Regardless of what you decide to do about the whole combiner thing you're going to have to put on your detective hat with a multimeter in hand and do some sleuthing.

Best of luck. Be sure to get back to us with some follow up. We all want to keep learning.

 

[kerryb]

Worked last three days sleuthing, but still have not solved the problem. Did find a hint at what might have been the cause. There is a ground cable that runs from the stay to the keel. There is a block that had a fuse like device in it that was simply blown apart. I think it may be a diode of some sort. Only marking in a round ceramic like piece is CLAUDE 91 230V. Took it in to two WM and a BOW but no one recognized what it might be, or could not find in their catalogs. I searched online for diodes, but never found anything that looked like it. It is a Beneteau Oceanis 400 that was made in France. Going to call Beneteau tomorrow to see if they can help.

 

[kerryb]

Here is a crude drawing of the device.