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bxroads
07-09-2009, 12:32 PM
In typical bxroads fashion, I’m agonizing over this darn auxiliary battery install. To summarize, I used Diesel’s “dumb” relay system and it’s installed exactly like he has diagramed. The 2nd battery is wired in parallel with the relay breaking the positives. The relay works as advertised. When the key is “off” and “acc” the relay is not energized and the connection is broke. I can hear and feel (with my hand) the relay switching. When tested with a digital multimeter there is no continuity between the two positive posts on the relay. When the key is “on” the relay is energized and there is continuity between the two positive posts on the relay.

All is well until I connect the on board Guest charger. It’s a dual charger and when connected to both batteries I have continuity between both positive posts on the relay. This occurs when the charger is plugged and unplugged, regardless. The relay is still “working”. I hear/feel it click when the ignition is turned to “on” and hear/feel it click when the ignition is turned to “off”. But I still get continuity between the positive posts at all times.

I then disconnected the 1st battery (starting battery) from the charger. So the charger is now only connected to the 2nd battery. I still get strange results. Like always, the relay is “working” (feel/hear it switch). Most of the time when in the “off” and “acc” position I get no continuity between the positive posts. But sometimes there is continuity and it seems to be when I have the charger plugged in. Continuity is haphazard in that sometimes when the charger is plugged in there is continuity in the “off” position and sometimes there is not.

1 – If the relay is working (feel/hear it click) is it most likely that it is truly breaking the connection?

2 – If it is truly breaking the connection then the charger is causing the continuity when the relay is off.

3 – If the charger is causing the continuity is there enough flow that the auxiliary battery will drain the starting battery?

4 – Using the multimeter is there a way to test the flow of electricity to/from each battery? All I know how to do is test the battery volts and continuity.

Advice will be greatly appreciated.

bxroads
07-09-2009, 02:51 PM
Any electricians out there? Maybe Jim will stop by shortly.

bxroads
07-09-2009, 03:22 PM
Reading through the "Ground" thread made me think I'd better add some more info. There is a total of two batteries. The 2nd is wired in parallel to the first with 2/0 (2 ought) cable. The system has two amps. The 2nd battery has four wires connected to each terminal; 1) Lead from first battery 2) Amp #1 3) Amp #2 4) Battery charger. Everything else is through the first battery; head unit, relay ground, wireless RF remote, etc.

JimN
07-09-2009, 03:31 PM
In typical bxroads fashion, I’m agonizing over this darn auxiliary battery install. To summarize, I used Diesel’s “dumb” relay system and it’s installed exactly like he has diagramed. The 2nd battery is wired in parallel with the relay breaking the positives. The relay works as advertised. When the key is “off” and “acc” the relay is not energized and the connection is broke. I can hear and feel (with my hand) the relay switching. When tested with a digital multimeter there is no continuity between the two positive posts on the relay. When the key is “on” the relay is energized and there is continuity between the two positive posts on the relay.

All is well until I connect the on board Guest charger. It’s a dual charger and when connected to both batteries I have continuity between both positive posts on the relay. This occurs when the charger is plugged and unplugged, regardless. The relay is still “working”. I hear/feel it click when the ignition is turned to “on” and hear/feel it click when the ignition is turned to “off”. But I still get continuity between the positive posts at all times.

I then disconnected the 1st battery (starting battery) from the charger. So the charger is now only connected to the 2nd battery. I still get strange results. Like always, the relay is “working” (feel/hear it switch). Most of the time when in the “off” and “acc” position I get no continuity between the positive posts. But sometimes there is continuity and it seems to be when I have the charger plugged in. Continuity is haphazard in that sometimes when the charger is plugged in there is continuity in the “off” position and sometimes there is not.

1 – If the relay is working (feel/hear it click) is it most likely that it is truly breaking the connection?

2 – If it is truly breaking the connection then the charger is causing the continuity when the relay is off.

3 – If the charger is causing the continuity is there enough flow that the auxiliary battery will drain the starting battery?

4 – Using the multimeter is there a way to test the flow of electricity to/from each battery? All I know how to do is test the battery volts and continuity.

Advice will be greatly appreciated.

Relays are switches and they are wires in series from the charging lead to the battery they're connected to, not parallel. Parallel would mean that one post would have the positive and the other would connect to the negative.

The relay has a pair of posts that should be connected to a ground and one that goes to something that activates it, so it will make current flow to something. One of the other posts is connected to the charging lead side of the circuit and the other post connects to the positive post of the battery, interrupting current flow. If you have a test light or voltmeter, disconnect the second battery and switch the relay off. If you test for voltage, you should see none. Switch the relay so it's ON and you should see voltage. The negative remains connected at all times- you're only switching the positive feed. If you're switching power to both batteries, the wire that connects to the charging lead goes to the input post on the relay and the output post connects to both batteries, at their positive posts. The problem with doing it this way is that both batteries are connected to each other and one can draw the other down. If you're using the relay to isolate the batteries, you would be able to drain one without affecting the other until the relay connection is closed.

JimN
07-09-2009, 03:38 PM
Reading through the "Ground" thread made me think I'd better add some more info. There is a total of two batteries. The 2nd is wired in parallel to the first with 2/0 (2 ought) cable. The system has two amps. The 2nd battery has four wires connected to each terminal; 1) Lead from first battery 2) Amp #1 3) Amp #2 4) Battery charger. Everything else is through the first battery; head unit, relay ground, wireless RF remote, etc.

Every piece in the audio system should be connected to the same battery. The main battery should be connected as it came from the factory but the second should be wired in parallel with the first, but the relay should be in line with the positive cable that connects the two batteries. The ground cables should be connected at the main battery, with a heavier one going to the block since the charging system is working harder and conducting more current.

If you don't have fuses or breakers on the positive cables within 12" of the second battery's positive post, you need to install them. A better way is to run one heavy positive cable to a distribution block and connect the amps to that, with a breaker on the heavy positive cable. Use a distribution block on the ground cables in the same way, using black instead of red.

bxroads
07-09-2009, 04:08 PM
Jim, thanks for the response.

Do you have any insight on the continuity issue when the battery charger is connected?

JimN
07-09-2009, 06:30 PM
Jim, thanks for the response.

Do you have any insight on the continuity issue when the battery charger is connected?

Is it the usual kind of charger that clamps onto the battery posts? If not, can you post a link to it? I seem to remember you posting that it's inline and I don't remember seeing anything like that.

TallRedRider
07-09-2009, 06:53 PM
Which relay are you using?

BriEOD
07-09-2009, 07:05 PM
All is well until I connect the on board Guest charger. It’s a dual charger and when connected to both batteries I have continuity between both positive posts on the relay. This occurs when the charger is plugged and unplugged, regardless. The relay is still “working”. I hear/feel it click when the ignition is turned to “on” and hear/feel it click when the ignition is turned to “off”. But I still get continuity between the positive posts at all times.

LMAO!

I think I know your problem. It freaked me out as well.

Take your multimeter and ground it. Then touch either + positive side of the relay. You should see voltage. What you are getting is just the battery on that side of the relay, not both batteries in parallel.

bxroads
07-09-2009, 08:08 PM
Jim, its the usual kind of charger that clamps to the battery posts. It is permanently mounted in the boat and has a line for each battery. Ring terminals permanently attach it to the battery. Dual 2611A (http://www.marinco.com/product/10-amp-dual-battery-chargepro-charger-0)

Go Red, I ordered from NAPA the BW that Diesel recommends but received the Echlin AR158, though I think its the same thing. Remember, the relay is working like it should when the battery charger is not connected.

Brian, bear with me. What you said confuses me. If I do not get continuity between the posts when in the key is in the "off" position and the battery charger is not connected then why should I get continuity in the same situation but with the battery charger connected to each battery.

JimN
07-09-2009, 09:53 PM
Jim, its the usual kind of charger that clamps to the battery posts. It is permanently mounted in the boat and has a line for each battery. Ring terminals permanently attach it to the battery. Dual 2611A (http://www.marinco.com/product/10-amp-dual-battery-chargepro-charger-0)

Go Red, I ordered from NAPA the BW that Diesel recommends but received the Echlin AR158, though I think its the same thing. Remember, the relay is working like it should when the battery charger is not connected.

Brian, bear with me. What you said confuses me. If I do not get continuity between the posts when in the key is in the "off" position and the battery charger is not connected then why should I get continuity in the same situation but with the battery charger connected to each battery.

If you have one battery + on each large post, you'll see voltage on each as BriEOD says, but you really can't get a valid continuity reading with the batteries connected and voltage present. In the Continuity setting, a small DC voltage comes out of the meter and the voltage drop is calculated internally, using the Ohm's Law formula (we all know how small calculators can be). This means that if the meter sees the same/more voltage, you'll see 0 Ohms or a reading with a negative sign. If you want to check continuity, you must have the large posts empty.

If the charger is connected or not, you'll see voltage on both posts with both batteries at any decent state of charge. If you disconnect one set of leads to the charger and it's not energized but you still see voltage on the disconnected positive lead, the charger has a problem.

Is the point of using the relay to be able to charge the batteries separately and discharge the second battery without bothering the main one? Are you not able to charge both batteries with your alternator?

bxroads
07-09-2009, 10:20 PM
Jim, Thanks! I think I've got it now. If I understand correctly, just because there is continuity between the positive posts on the relay while the batteries are attached does not mean there's a problem.

The objective of the relay is as Diesel described in the "Official Battery Thread". I'm sorry if I was not clear. The relay is to cut off the auxiliary when the key is turned to "off" and "acc" so that it doesn't drain the starting battery. When the key is "on" the relay connects the aux battery to the starting battery and charges.

I have bare minimum electronics other than the sound system. My boat (2008 190 with LY6) came standard with a 90 amp alternator.

I just installed the auxiliary battery and have not really tested it on the water. I am just being cautious that I've done everything right so that I don't get stuck anchored on the island. I'll check the starting battery with my meter from time to time to verify that its not being drained with the aux battery.

Thanks again.

Clint

BriEOD
07-09-2009, 10:23 PM
Clint you've got it. Jim explained it much more eloquently than I did. But, based on what I've read, I had the same oh shoot moment as you with my multi-meter. Once I thought about it I relaxed.

JimN
07-09-2009, 10:34 PM
Jim, Thanks! I think I've got it now. If I understand correctly, just because there is continuity between the positive posts on the relay while the batteries are attached does not mean there's a problem.

The objective of the relay is as Diesel described in the "Official Battery Thread". I'm sorry if I was not clear. The relay is to cut off the auxiliary when the key is turned to "off" and "acc" so that it doesn't drain the starting battery. When the key is "on" the relay connects the aux battery to the starting battery and charges.

I have bare minimum electronics other than the sound system. My boat (2008 190 with LY6) came standard with a 90 amp alternator.

I just installed the auxiliary battery and have not really tested it on the water. I am just being cautious that I've done everything right so that I don't get stuck anchored on the island. I'll check the starting battery with my meter from time to time to verify that its not being drained with the aux battery.

Thanks again.

Clint

Once again, you can't check for continuity with the batteries connected. You're seeing voltage, which is a different matter. If you set the meter to Volts, ground the negative lead of the meter and see voltage on both posts, you're not checking continuity. Again, if you want to make sure the relay is doing its job, remove one battery cable at a time from it and check for voltage on the bare post with the key ON and OFF. If you only see voltage when the key is ON, it's working. If you see really small numbers when the key is OFF, like 50mV, don't worry about it. Humid air will conduct that well but it won't cause a problem.

As long as the aux battery is grounded to the same place as the main one, you should be OK.

JimN
07-09-2009, 10:35 PM
Clint you've got it. Jim explained it much more eloquently than I did. But, based on what I've read, I had the same oh shoot moment as you with my multi-meter. Once I thought about it I relaxed.

Call me 'eloquent' again and we'll have words!:mad:

JimN
07-09-2009, 10:37 PM
Clint you've got it. Jim explained it much more eloquently than I did. But, based on what I've read, I had the same oh shoot moment as you with my multi-meter. Once I thought about it I relaxed.

Ever tried measuring voltage after measuring current, but forgot to change the position of the leads? Now that's an Oh schnit moment. The meter's fuse does not like that. Makes the inside of the glass tube shiny.

BriEOD
07-09-2009, 10:53 PM
Ever tried measuring voltage after measuring current, but forgot to change the position of the leads? Now that's an Oh schnit moment. The meter's fuse does not like that. Makes the inside of the glass tube shiny.

No, but have checked continuity on electric blasting caps when someone forgot the "approved" tester. Talk about a pucker moment.

JimN
07-09-2009, 11:48 PM
No, but have checked continuity on electric blasting caps when someone forgot the "approved" tester. Talk about a pucker moment.

Is the "approved" tester a big, black Simpson analog meter? Those put out a couple of Amps in Continuity mode.

bxroads
07-10-2009, 12:36 AM
Once again, you can't check for continuity with the batteries connected. You're seeing voltage, which is a different matter. If you set the meter to Volts, ground the negative lead of the meter and see voltage on both posts, you're not checking continuity. Again, if you want to make sure the relay is doing its job, remove one battery cable at a time from it and check for voltage on the bare post with the key ON and OFF. If you only see voltage when the key is ON, it's working. If you see really small numbers when the key is OFF, like 50mV, don't worry about it. Humid air will conduct that well but it won't cause a problem.

As long as the aux battery is grounded to the same place as the main one, you should be OK.



Jim, I did as you said (remove one cable at a time and test voltage) and everything is checking out OK. Thanks!

Brian, thanks for your help as well.

BriEOD
07-10-2009, 03:41 PM
Is the "approved" tester a big, black Simpson analog meter? Those put out a couple of Amps in Continuity mode.

No, military grade tester with a special silver chloride battery which keeps the amps well below the threshold.

bxroads
07-10-2009, 10:57 PM
LMAO!

I think I know your problem. It freaked me out as well.

Take your multimeter and ground it. Then touch either + positive side of the relay. You should see voltage. What you are getting is just the battery on that side of the relay, not both batteries in parallel.

I've been out testing again (I'm a little hard headed) and it works perfect! Can't imagine why I didn't think of testing the volts vs continuity. I feel a little better knowing I'm not the Lone Ranger.:D

BriEOD
07-10-2009, 11:14 PM
I've been out testing again (I'm a little hard headed) and it works perfect! Can't imagine why I didn't think of testing the volts vs continuity. I feel a little better knowing I'm not the Lone Ranger.:D

Deep breath. Diesel didn't steer you wrong.:D