"Dual battery" load on regulator

[naghani]

Fellow boaters
I connected my spare battery, parallel to the other battery (+ to + and - to -). Now I can run the starter longer.
Questions:
1- Is it bad for regulator (e.g. consuming more current)?
2- What does the voltmeter on dashboard (Bayliner Capri 1990) show? Charging voltage (after regulator voltage=battery voltage)?
3- In the first half an hour of cruise, the dash voltmeter shows 12-13v....but after a while it gets higher and higher, till 16-17v! Is it normal?
4- When the voltmeter is 17v, are my batteries boiling and losing water???


Thanks
nozar

 

[bruceb58]

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Re:

The regulator/alternator really doesn't care how you hooked up the batteries if they are in parallel.

The guage on your dash is going to read the voltage at the dash...it should be the same as the battery if there are no voltage drops between the battery and your dash.

If it's reading 17V it sounds like you blew the regulator in your alternator some how. Did you ever run the engine with the batteries disconnected?

Check with a handheld meter right at the battery to see what you are really getting. Should be a little over 14V while charging. If you are getting 17V you would be damaging your battery.

 

[Silvertip]

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Since we have no idea what engine you are talking about, it may be that your engine does not even have a regulator. It may have just a rectifier and as the batteries become charged the voltmeter will continue to rise. If you are make very long wide open throttle runs it may be that you will boil the batteries. If one of those batteries is a deep cycle, that may contribute to the problem. Try turning on some accessories when the voltage is in the 15 - 17V range. If it drops below 15V the system is functioning normally.