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Battery Isolator

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G&G

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Hello, I have a 1989 Evinrude 120hp outboard engine installed on my Pontoon. I have tried several times at Installing a battery isolator to separate my starting battery from my accessory battery in an attempt to charge both when the engine is running. I have tried the battery doctor version and now I have the Newmar 1/2/70 Isolator model 702. I have search the web high and low and I have the general idea of how it's to be installed, but my failing point has to be the "Alternator" hook up. I know the engine has a stator and a rectifier that control the electrical part of the charging. My sticking point is what wire do I connect to the Isolator as the "Alternator"? Is it a wire from the rectifier or the purple wire from the harness or am I way off???? Thanks in advance for any assistance.
 
The red, DC positive output wire from the rectifier regulator must be re-routed to the "A" terminal of the Newmar battery isolator.

Be aware that this is a diode type of device and that there will be a significant voltage drop across it ( approx 0.7 volt ) My understanding is that the purple wire is a voltage sensing wire and that if this remains connected to one of the batteries the regulator will compensate for this voltage drop. However replacement rectifier/regulators may not have the purple wire, voltage sensing being internal. This may cause poor charging if the r/r is replaced with one without the purple wire.

Personally I would have chosen a VSR ( voltage sensitive relay ) type of battery isolator, which would not suffer from voltage drop of a diode splitter type.
 
G&G said:
Hello, I have a 1989 Evinrude 120hp outboard engine installed on my Pontoon. I have tried several times at Installing a battery isolator to separate my starting battery from my accessory battery in an attempt to charge both when the engine is running. I have tried the battery doctor version and now I have the Newmar 1/2/70 Isolator model 702. I have search the web high and low and I have the general idea of how it's to be installed, but my failing point has to be the "Alternator" hook up. I know the engine has a stator and a rectifier that control the electrical part of the charging. My sticking point is what wire do I connect to the Isolator as the "Alternator"? Is it a wire from the rectifier or the purple wire from the harness or am I way off???? Thanks in advance for any assistance.
Click to expand...

vics said:
The red, DC positive output wire from the rectifier regulator must be re-routed to the "A" terminal of the Newmar battery isolator.

Be aware that this is a diode type of device and that there will be a significant voltage drop across it ( approx 0.7 volt ) My understanding is that the purple wire is a voltage sensing wire and that if this remains connected to one of the batteries the regulator will compensate for this voltage drop. However replacement rectifier/regulators may not have the purple wire, voltage sensing being internal. This may cause poor charging if the r/r is replaced with one without the purple wire.

Personally I would have chosen a VSR ( voltage sensitive relay ) type of battery isolator, which would not suffer from voltage drop of a diode splitter type.
Click to expand...

The Battery Doctor battery isolator is an electronically controlled VSR type of device. It should have been a good choice and easier to fit as it requires no alteration to the engine wiring, merely connections to each battery positive terminal and a negative connection for its internal electronics.

What was the problem with it ?
 
vics said:
The Battery Doctor battery isolator is an electronically controlled VSR type of device. It should have been a good choice and easier to fit as it requires no alteration to the engine wiring, merely connections to each battery positive terminal and a negative connection for its internal electronics.

What was the problem with it ?
Click to expand...

I'm almost positive the person who put it in initially had it installed incorrectly, so I though switching it out might be easier. They way they were wired, my second battery would always die. It would never charge.
 
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