Battery Chargers & Isolators

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Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Kevin, what you described means just

the opposite of your conclusion. If the banks stay at 12.7+ volts when you DISCONNECT the charger lead, BUT are DIFFERENT when you keep the charger connected, then it could be that there is NO isolation. Are the outputs of the charger to cable clamps (alligator clips) or hard wired? Have you checked the manufacturer's website to see, and are there any indications in the instruction manual that recommend disconnecting the charger after use? Something sounds fishy if you do indeed need isolators, because they drop more than half a volt between the charger and the banks and is no longer a recommended method of isolating battery banks because of poor charging because of lower voltage. Some more input is needed for us to help you out here.
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Kevin, what you described means just

the opposite of your conclusion. If the banks stay at 12.7+ volts when you DISCONNECT the charger lead, BUT are DIFFERENT when you keep the charger connected, then it could be that there is NO isolation. Are the outputs of the charger to cable clamps (alligator clips) or hard wired? Have you checked the manufacturer's website to see, and are there any indications in the instruction manual that recommend disconnecting the charger after use? Something sounds fishy if you do indeed need isolators, because they drop more than half a volt between the charger and the banks and is no longer a recommended method of isolating battery banks because of poor charging because of lower voltage. Some more input is needed for us to help you out here.
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Kevin, what you described means just

the opposite of your conclusion. If the banks stay at 12.7+ volts when you DISCONNECT the charger lead, BUT are DIFFERENT when you keep the charger connected, then it could be that there is NO isolation. Are the outputs of the charger to cable clamps (alligator clips) or hard wired? Have you checked the manufacturer's website to see, and are there any indications in the instruction manual that recommend disconnecting the charger after use? Something sounds fishy if you do indeed need isolators, because they drop more than half a volt between the charger and the banks and is no longer a recommended method of isolating battery banks because of poor charging because of lower voltage. Some more input is needed for us to help you out here.
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Kevin, what you described means just

the opposite of your conclusion. If the banks stay at 12.7+ volts when you DISCONNECT the charger lead, BUT are DIFFERENT when you keep the charger connected, then it could be that there is NO isolation. Are the outputs of the charger to cable clamps (alligator clips) or hard wired? Have you checked the manufacturer's website to see, and are there any indications in the instruction manual that recommend disconnecting the charger after use? Something sounds fishy if you do indeed need isolators, because they drop more than half a volt between the charger and the banks and is no longer a recommended method of isolating battery banks because of poor charging because of lower voltage. Some more input is needed for us to help you out here.
 
B

BobW

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Jul 21, 2005
456
Hunter 31 San Pedro, Ca
You seem to have a charger problem, KevinB...

but it's definitely not one battery 'draining into' the other. A 12v battery's fully-charged, open-circuit voltage will be somewhere between 12.6 and 12.8 volts. When you read 13.3 volts, either with the charger running, or shortly after the charger is turned off, that is the charger voltage, not the battery voltage. The charger voltage will drop after it is shut off as its internal capacitors discharge. The charger appears to be doing the draining, and I suspect it is faulty, since it has..... memory time here.... deep dark recesses..... I think it is called a 'blocking diode', which only allows current to flow one direction - in this case, towards the battery. I strongly suspect your charger is faulty. If you can return it, by all means do so. If not, you could probably install an external blocking diode, but you'd still need to worry about what else might be wrong inside... particularly something that could cause a fire. Cheers, Bob s/y X SAIL R 8
 
B

BobW

.
Jul 21, 2005
456
Hunter 31 San Pedro, Ca
You seem to have a charger problem, KevinB...

but it's definitely not one battery 'draining into' the other. A 12v battery's fully-charged, open-circuit voltage will be somewhere between 12.6 and 12.8 volts. When you read 13.3 volts, either with the charger running, or shortly after the charger is turned off, that is the charger voltage, not the battery voltage. The charger voltage will drop after it is shut off as its internal capacitors discharge. The charger appears to be doing the draining, and I suspect it is faulty, since it has..... memory time here.... deep dark recesses..... I think it is called a 'blocking diode', which only allows current to flow one direction - in this case, towards the battery. I strongly suspect your charger is faulty. If you can return it, by all means do so. If not, you could probably install an external blocking diode, but you'd still need to worry about what else might be wrong inside... particularly something that could cause a fire. Cheers, Bob s/y X SAIL R 8
 
B

BobW

.
Jul 21, 2005
456
Hunter 31 San Pedro, Ca
You seem to have a charger problem, KevinB...

but it's definitely not one battery 'draining into' the other. A 12v battery's fully-charged, open-circuit voltage will be somewhere between 12.6 and 12.8 volts. When you read 13.3 volts, either with the charger running, or shortly after the charger is turned off, that is the charger voltage, not the battery voltage. The charger voltage will drop after it is shut off as its internal capacitors discharge. The charger appears to be doing the draining, and I suspect it is faulty, since it has..... memory time here.... deep dark recesses..... I think it is called a 'blocking diode', which only allows current to flow one direction - in this case, towards the battery. I strongly suspect your charger is faulty. If you can return it, by all means do so. If not, you could probably install an external blocking diode, but you'd still need to worry about what else might be wrong inside... particularly something that could cause a fire. Cheers, Bob s/y X SAIL R 8
 
B

BobW

.
Jul 21, 2005
456
Hunter 31 San Pedro, Ca
You seem to have a charger problem, KevinB...

but it's definitely not one battery 'draining into' the other. A 12v battery's fully-charged, open-circuit voltage will be somewhere between 12.6 and 12.8 volts. When you read 13.3 volts, either with the charger running, or shortly after the charger is turned off, that is the charger voltage, not the battery voltage. The charger voltage will drop after it is shut off as its internal capacitors discharge. The charger appears to be doing the draining, and I suspect it is faulty, since it has..... memory time here.... deep dark recesses..... I think it is called a 'blocking diode', which only allows current to flow one direction - in this case, towards the battery. I strongly suspect your charger is faulty. If you can return it, by all means do so. If not, you could probably install an external blocking diode, but you'd still need to worry about what else might be wrong inside... particularly something that could cause a fire. Cheers, Bob s/y X SAIL R 8
 
D

Dan

Easy enough to check

If the charger is draining one battery into the other as you suspect, after charging, remove the + lead from charger to the battery and measure the voltage between the disconnected battery and the lead you lifted. If there is no voltage present, the charger is isolated. I think you are seeing differences in voltage due to the batteries are a different type. One is starting and one is deep cycle. Then they settle out at their normal voltage, 12.7, which isn't bad. Once you've charged the batteries, disconnect the charger. Measure the voltage in the batteries after 24 hours. With both + leads removed from the charger, measure for continuity between both + legs of the charger. That will tell you if there is a problem.
 
K

KevinB

Stu, you are correct.....

it looks like I don't have isolation (that's what I originally meant to say). To answer your questions. The output leads are hard wired to the batteries. And there is nothing in either the web site or the manual saying you have to disconnect the leads after charging. The feedback I have received so far (and my reading of the archives) is answering my question; which is these types of chargers should have built in isolation (the diagrams on the ProMariner web site and manual don't show external isolators being used, which leads one to believe it has built in isolation) and therefore my charger probably has a defect. What got me second guessing this conclusion was the salesperson at my marine store being insistent that he was told all of these types (including the other brands they sell) of battery chargers require external battery isolators. Hopefully I'll hear back from ProMariner early next week to get them to confirm if their charger supports isolation. Thanks, Kevin
 
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dan

I didn't mean all the time

I didn't mean to disconnect the leads every time you charge the batteries. What I meant was disconnecting the charger only once while you have it on the bench for a test. You should not have to disconnect the charger, ever, normally. But to run a test you need to isolate the system to see if it still acts the same way. It a troubleshooting procedure. How are you measuring the voltage? Do you have a multi- meter? Having external isolators would cause the charger to see a higher voltage at the charger output leads and would then continuously under-charge the batteries. So I don’t believe you need them. They probably have MOSFETS that isolate the batteries (as opposed to diodes) and one might be defective, but you have to disconnect it, to test it. If you disconnect the charger and check the batteries voltage after 24 hours, and the batteries act the same way, that's part of the puzzle. Check the charger with a meter and see if there is continuity between both positive leads. IF there is continuity, the charger is definitely defective. I’ll go and check mine for continuity and see if there is a closed circuit or not and I'll report back in a little bit. Over and out, Dan
 
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Dan

Hmmm... Sumptin fishy here

Second paragraph of the instruction manual says, "These units should be permanently installed in your boat and hardwired directly to your batteries." The next sentenane says, "They are designed with three isolated outputs that can sense and charge three heavy duty battery banks as needed." (Mine is a three bank charger) However, I read continuity between all three outputs. With my meter on the 2K ressitance scale, the meter reads, 1.9K resistance. That aint good. So they are connected. Hmmmmm If they're designed with three isolated outputs, why can I read continuity? When I get into this resistance stuff, I don't get it very quickly, I need to think about it. I'll wait and see what Promariner tells you. It will be interesting. Dan
 
S

Steve Dion

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Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Think about a quality charger

Kevin: Think about a quality battery charger. I assume that this charger is normally installed in your boat. If you are depending on this charger to start your engine it WILL cause you a problem when you need it the most. Take a look a the Xantrex Truecharge 20+. It will charge up to 3 battery banks and will do the 3 different battery chemistries too. If you want a really cool charger, then Xantex makes the new XC series. This will allow you to have mixed chemistries all on the same charger at the same time.
 
Stu Jackson

Stu Jackson

.
Feb 26, 2004
23,345
Catalina 34 224 Maple Bay, BC, Canada
Is your charger a Flyback model?

If it is, please let me know. Those have been known to start fires on board. Really. If you do, I can point you to some previously published personal experiences that suggest that Steve Dion's recommendations should be implemented. Here's one: http://c34.org/bbs/index.php?topic=3716.0
 
professor bills

professor bills

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Dec 12, 2007
8
- - St. pete
not sure we are all talking teh same thing

But I'll throw my 2cents in. If you have a charger with multiple outputs and not just tw wires spliced into one output, the outputs should be isolated. It sounds as if the charger may be draing one battery due to the fact that the problem is following teh charger leads. Aside from that two things to remember theoretically a perfect battery will not stay above 12.6 volts (2.1 volts per cell) once disconnected froma charging system. Also if you are checking a diode with a digital ohmmeter the ohmeter must be set to the diode checking position. Thats the position with the diode symbol which is a sideways triangle wiht a line at the point. Diodes will allow current to flow through both ways on digital ohmmeters. In conclusion, judging by what I have read your charger has a problem with it.
 
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Dan H

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Oct 9, 2005
143
Catalina C25 SW Michigan
Yup it is a Flyback

I wish I would have known about this when I bought it. Obviously I wouldn't have bought it. I'll be calling them in the morning. Thanks Stu
 
A

Andy

Check for Jumper Wire

There should be a jumper cable between #2 and #3 if you only have two batteries. The ProMariner on our 340 is capable of being wired to three batteries. The instruction manual says to wire directly to the positive post of each battery and if there is only two, there should be a jumper wire (sometimes a little brass plate) that combines the output of #2 and #3 positive. I added a third battery, took out the jumper and wired them directly to from charger to battery. Hunter factory wires the positive charger wire through the battery isolation/selector. Check the archives and you will see that ProMariner and Hunter seem to disagree as to which way is "best" or "proper".
 
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KevinB

The charger is for use at home...

Steve, I store my batteries off the boat at home during the winter so the ProMariner was for use in the garage where I would normally just plug in the charger 2-3 times a month for a couple of hours. It seemed well priced for that purpose. I agree with you that when it comes to the boat we shouldn't skip on quality and that's my normal approach. I guess the lesson learned with the ProMariner just re-enforces that thinking. Thanks, Kevin
 
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KevinB

Andy, The ProSport12 is for two batteries....

so the jumper doesn't enter into the picture. Thanks
 
A

Andy

ProSport 12 vs Flyback

I did a quick check of the ProMariner site and reread the postings. I see now that YOU have the ProSport and Dan has the Flyback. My bet is the Flyback has a jumper like my ProTech-4. So I'm all wet on being any help. When you hear back from ProMariner, perhaps you can tell us if the problem gets resolved. I had better luck emailing ProMariner. I guess the electric engineers on this site will chime in soon-wonder if combining deep cycle and starting batteries are causing a problem? I choose to use a house bank of two deep cycles wired parellel and a starting bank of one combination deep/start battery. What boat will is this be on?
 
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