Dual Battery Hook up with an Isolator. Will this work: I have a model 490 - 90 amp. rated isolator off a vehicle and I'm thinking of installing it on my M-26X. My motor is a Suzuki - 50 - 4 S and puts out 18 amps. My plan at this point is to disconnect the altenator wire off my 50 HP ( after it comes off the rectafier ) and simply attaching it to the altenator post on the isolator using #10 wire. Then attaching main and auxiliary battery to isolator also using #10 wire. Final step is to join the negative terminals of the two batteries. Does this seem correct or would I have problems or any negative side effects? My goal is to only start my motor off #1 battery and run all other electrical off #2 using the isolator to charge both batteries.. Thanks Cory
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Timm MIller
Isolator
Leave your primary battery hooked up as is....then run leads off to the isolator and connect second battery to isolator and have all grounds connected. I have an isolator for RV's and it works fine. Once primary battery is topped off (13.8vdc)the isolator will trip and allow charging to second battery.
Leave your primary battery hooked up as is....then run leads off to the isolator and connect second battery to isolator and have all grounds connected. I have an isolator for RV's and it works fine. Once primary battery is topped off (13.8vdc)the isolator will trip and allow charging to second battery.
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Cory
Don't understand
Are you saying Timm not to run the altenator wire from the motor to the isolator but to leave it as it was originally hooked up to my battery. Then run a wire from the main battery to isolator and a wire from the isolator to my second battery?? No hook up to the middle terminal ( altenator terminal). Plus connect the two negative posts? I thought a current would only flow one way on an isolator? Cory
Are you saying Timm not to run the altenator wire from the motor to the isolator but to leave it as it was originally hooked up to my battery. Then run a wire from the main battery to isolator and a wire from the isolator to my second battery?? No hook up to the middle terminal ( altenator terminal). Plus connect the two negative posts? I thought a current would only flow one way on an isolator? Cory
Isolator install
What battery switch system are you using? I use three switches and a battery combiner to my three batteries in two banks. Works great. Isolators and combiners both flow one way, that's the whole purpose. Isolators just create more heat and waste more current. With the two motor leads going directlly to the engine battery, and the isolator between the engine and other battery(s) the engine will charge the engine battery first, then the second. Engine will start from the first in line, and NOT draw any charge from the second in line. The second battery drawing down can only draw on itself or the engine it cannot draw on the engine battery. I fooled around for 30 years with various combinations and found the three switch system as illustrated in the current WestMarine catalog is perfect with a West Marine 50 combiner. I used the Blue Sea Systems's mini switches. Picutres available upon request.
What battery switch system are you using? I use three switches and a battery combiner to my three batteries in two banks. Works great. Isolators and combiners both flow one way, that's the whole purpose. Isolators just create more heat and waste more current. With the two motor leads going directlly to the engine battery, and the isolator between the engine and other battery(s) the engine will charge the engine battery first, then the second. Engine will start from the first in line, and NOT draw any charge from the second in line. The second battery drawing down can only draw on itself or the engine it cannot draw on the engine battery. I fooled around for 30 years with various combinations and found the three switch system as illustrated in the current WestMarine catalog is perfect with a West Marine 50 combiner. I used the Blue Sea Systems's mini switches. Picutres available upon request.
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Cory
Thanks for the info
Thanks Night Sailor for the information. I'll look into that system. Are you saying my method will work ... but there is a better way. You stated the isolator causes heat .... Is this a concern ? My battery area is quite large. My understanding is that the isolator will divide my amps to each battery. The motor gives 18 amps therefore 9 amps to each battery. Is this what you mean by wasting current? Cory
Thanks Night Sailor for the information. I'll look into that system. Are you saying my method will work ... but there is a better way. You stated the isolator causes heat .... Is this a concern ? My battery area is quite large. My understanding is that the isolator will divide my amps to each battery. The motor gives 18 amps therefore 9 amps to each battery. Is this what you mean by wasting current? Cory
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Timm MIller
Banks
There are many ways to wire this up.....you can keep it simple or make it complex as you want. The more complex it becomes, the more likely it will be to fail when you least expect it. The positive and negative battery wires coming from your motor that attach to your battery is all you need to keep a charge on your starting battery......it puts out what it needs by reading the voltage on the battery....once it is topped off.....it maintains a floating charge. As I stated before, if you left your current setup as is....you would mearly place the isolator close to you starting battery.....it has connections for positive leads only. One would be for the starting battery...the other would be for your house bank. Once your starting battery has recovered from the start up, the isolator waits for the starting battery to reach about 13.8 vdc....once it does, it trips and the flow starts going to the house batteries. When you shut the motor down, it trips to off and seperates the house batteries from the starting battery. It's like an automatic switch. It's a simple setup and it works. Mine has a jumper, in the event that for whatever reason, the starting battery fails, I can use the house batteries for starting......this is what a selectable switch would do if incorporated into the design....after three years, I have never had to do it.
There are many ways to wire this up.....you can keep it simple or make it complex as you want. The more complex it becomes, the more likely it will be to fail when you least expect it. The positive and negative battery wires coming from your motor that attach to your battery is all you need to keep a charge on your starting battery......it puts out what it needs by reading the voltage on the battery....once it is topped off.....it maintains a floating charge. As I stated before, if you left your current setup as is....you would mearly place the isolator close to you starting battery.....it has connections for positive leads only. One would be for the starting battery...the other would be for your house bank. Once your starting battery has recovered from the start up, the isolator waits for the starting battery to reach about 13.8 vdc....once it does, it trips and the flow starts going to the house batteries. When you shut the motor down, it trips to off and seperates the house batteries from the starting battery. It's like an automatic switch. It's a simple setup and it works. Mine has a jumper, in the event that for whatever reason, the starting battery fails, I can use the house batteries for starting......this is what a selectable switch would do if incorporated into the design....after three years, I have never had to do it.
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Timm MIller
Banks II
Some people like the idea of switches to isolate the batteries......this comes in handy in the event of parasitic drains.
Some people like the idea of switches to isolate the batteries......this comes in handy in the event of parasitic drains.
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Cory
Thanks for the info
Thanks Timm That seems so simple and saves a lot of work running an altenator wire from the motor to the battery compartment.I should have done more research into isolators. I didn't know the isolator would allow a one way current to flow from my main battery through the isolator to my 2nd battery with no connection to the altenator terminal on the isolator. Thangs again Cory
Thanks Timm That seems so simple and saves a lot of work running an altenator wire from the motor to the battery compartment.I should have done more research into isolators. I didn't know the isolator would allow a one way current to flow from my main battery through the isolator to my 2nd battery with no connection to the altenator terminal on the isolator. Thangs again Cory
complexity
Cory, I have outfitted my boat to be a self contained two week cruiser, and it has several small (milliamp) parasitic drains on the batteries. Stereo and 6 pack CD changer, smoke alarm, C0 Alarm. In addition, I have a small 12v thermoelectic Koolatron refrigerator that draws 3 amps and runs constantly when on more than day trips. We do most of our sailing at night, so more draw is taken than for day trips. For me, isolation of batteries is important because some of the places we gunkhole by motor would be impossible to sail from if the starting battery was to die. Swapping battery cables in a rolling sea would not be safe or fun. And although I could start the Merc 50 by rope pull, my wife couldn't, and I always plan on what could happen if I were disabled by flu, injury, or heart problems. Nothing wrong with having it as simple as the factory way, one battery, no isolation, it just doesn't account for human nature and all the accessories we like to have on board for convenience, pleasue or safety.
Cory, I have outfitted my boat to be a self contained two week cruiser, and it has several small (milliamp) parasitic drains on the batteries. Stereo and 6 pack CD changer, smoke alarm, C0 Alarm. In addition, I have a small 12v thermoelectic Koolatron refrigerator that draws 3 amps and runs constantly when on more than day trips. We do most of our sailing at night, so more draw is taken than for day trips. For me, isolation of batteries is important because some of the places we gunkhole by motor would be impossible to sail from if the starting battery was to die. Swapping battery cables in a rolling sea would not be safe or fun. And although I could start the Merc 50 by rope pull, my wife couldn't, and I always plan on what could happen if I were disabled by flu, injury, or heart problems. Nothing wrong with having it as simple as the factory way, one battery, no isolation, it just doesn't account for human nature and all the accessories we like to have on board for convenience, pleasue or safety.
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Cory
Yes better systems!!
Yes the switch or the combiner IS a better system. But I'm still wondering if my method will work to some degree. I don't have to cut into my altinator wire as I can simply join it at a bolt after removing the wire heading off to the original set up. The original wire can be taped so if I want to go back to factory it would be an easy step. But to get back to my original questions. 1) Will my set up work? 2) Will my vehicle isolator work or do I need a marine isolator? 3) Do I have to ground the isolator like on a vehicle? 4) Is joining the negative posts on the two batteries enough to allow current to flow? 5) On an isolator system does #1 charge first or the weaker battery or both at the same time. 6) On an isolator system when I use a battery charger do I have to disconnect anything - ie: wires to isolator? Cory
Yes the switch or the combiner IS a better system. But I'm still wondering if my method will work to some degree. I don't have to cut into my altinator wire as I can simply join it at a bolt after removing the wire heading off to the original set up. The original wire can be taped so if I want to go back to factory it would be an easy step. But to get back to my original questions. 1) Will my set up work? 2) Will my vehicle isolator work or do I need a marine isolator? 3) Do I have to ground the isolator like on a vehicle? 4) Is joining the negative posts on the two batteries enough to allow current to flow? 5) On an isolator system does #1 charge first or the weaker battery or both at the same time. 6) On an isolator system when I use a battery charger do I have to disconnect anything - ie: wires to isolator? Cory
Answers
1) Will my set up work? Yes 2) Will my vehicle isolator work or do I need a marine isolator? It will work, but I'd keep it in a dry environment 3) Do I have to ground the isolator like on a vehicle? You have to make the same connections in the boat as you would a vehicle. 4) Is joining the negative posts on the two batteries enough to allow current to flow? Yes 5) On an isolator system does #1 charge first or the weaker battery or both at the same time. With a diode isolator, both charge simultaneously. 6) On an isolator system when I use a battery charger do I have to disconnect anything - ie: wires to isolator? No
1) Will my set up work? Yes 2) Will my vehicle isolator work or do I need a marine isolator? It will work, but I'd keep it in a dry environment 3) Do I have to ground the isolator like on a vehicle? You have to make the same connections in the boat as you would a vehicle. 4) Is joining the negative posts on the two batteries enough to allow current to flow? Yes 5) On an isolator system does #1 charge first or the weaker battery or both at the same time. With a diode isolator, both charge simultaneously. 6) On an isolator system when I use a battery charger do I have to disconnect anything - ie: wires to isolator? No
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Cory
Thanks Moe
Thanks for the information. I will have to check with the manufacturer of my isolator to see if that model has to be grounded. I didn't think they had to but when I obtained this Isolator I think their was a wire under the screw holding it to the car frame to the fender.I don't know why the need for this wire as the isolator was screwed to the frame. One other point I'm wondering if I should go to a #8 wire from my altinator to my isolator due to the distance--- 10 feet ---???? #10 wire should be OK from the isolator to the batteries as they are close to each other. Lots to do and think about on a new(to me)boat. I can see myself changing to new systems. Thanks Cory
Thanks for the information. I will have to check with the manufacturer of my isolator to see if that model has to be grounded. I didn't think they had to but when I obtained this Isolator I think their was a wire under the screw holding it to the car frame to the fender.I don't know why the need for this wire as the isolator was screwed to the frame. One other point I'm wondering if I should go to a #8 wire from my altinator to my isolator due to the distance--- 10 feet ---???? #10 wire should be OK from the isolator to the batteries as they are close to each other. Lots to do and think about on a new(to me)boat. I can see myself changing to new systems. Thanks Cory
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