High Voltage!

[redjmp]

So I went to Wallyworld and got one of their marine heavy duty starting/deep cycle type 27 batteries because it was a great deal for such a large well built battery.
My 9 year old Crappy Tire deep cycle was finally starting to fail to start my 86 115.

I know the battery is fully topped up at 12.9 volts on deep cycle mode on my smart charger.

Between the battery and the helm electronics, I loose 2 volts and I am used to seeing 10.9 volts on my Humminbird FF when off and 12-13 volts when running.

So when running it sees ~14 - 15 volts from the engine.

But with this new battery I have seen the voltage on my Humminbird FF display slowly climb up while running to 16 volts meaning more like 18 at the battery and engine.

Then my Navman gps froze... maybe too much voltage?

Then my motor started missing and running rough at less than 4500 rpm...

I'm thinking I fried my switchbox maybe? Or maybe a coil started to overheat and fail.

Geez! Is this normal for a battery to allow the voltage to get that high?
Isn't it supposed to work like a voltage regulator especially when new to keep the volts down?

Plugs were new. Compression is good. Pulled off the carbs and they were clean...

Comments anyone?

 

[aussieflash]

Re: High Voltage!

Mine does the same and its normal for unregulated charge systems to peg around 16-17v while at higher rpms.My FF tolerates the high voltage to around 18v...i think.A good battery will pull volts down fairly quick at lower rpms or when motor is shut down.
Remember you will need to watch water level in battery as it tends to evaperate at higher volts.
This will not affect ignition system at all.