Battery Diodes

[95starcraft]

Has anybody heard of TNT Power, I had one on my boat when I bought it, it is a one way diode setup between the starter and deeps it allows the starter to pull juice to off the deeps so juice is always there to start the engine and run accessories. I checked the one way diode with a volt meter and found out the diodes are allowing voltage both ways, where can I find one. It is a type of isolater but not one that you hook up the alternator, I already have a 3 bank charger.

 

[Silvertip]

Re: Battery Diodes

You don't use a voltmeter to check a diode -- you use an ohm meter and one end of the diode must be out of the circuit. Obviously if you have power going into a diode it will measure voltage on that side. Current flow in the forward direction will show voltage on the other end as well. With an ohm meter you check continuity in one direction then reverse the meter leads and check continuity in the other. If you show continuity in both directions the diode is bad. A good diode will show continuity in one direction and not in the other.

 

[95starcraft]

Re: Battery Diodes

Yes I understand but when is there voltage on both ends, I gues I would have thought you only have voltage in one direction.

 

[Silvertip]

Re: Battery Diodes

Obviously you don't. I just explained that. If you measure on the battery side of the diode to ground you measure battery voltage. If you measure on the load side of the diode to ground you also measure battery voltage because that's the direction current is flowing. If you turn the diode around so the + end is on the positive terminal of the battery you will measure battery voltage on the + end but not the - end but then whatever you have connected in that circuit woulldn't work either because the diode is blocking current flow.

Post a diagram of the wiring of this thing. I'm guessing this thing does not perform the functions you think it does. An isolator cannot allow current flow in both directions.