Batteries dead - running rough after jump start

[rufnek100]

(1993 Baja 24' w/502 mag) The batteries (2) were run down to almost a complete discharge level over the holiday weekend. I had to jump it to start it. After gettting it running, it seemed to run very rough with a little black smoke coming from the exhaust (black smoke=ignition problems?). Now the voltmeter seems to be erratic between 10-13 volts. I didn't run it long enough to recharge the batteries with the alternator and from what I understand, boat alternators don't fully recharge them anyway.<br /><br />Could some bad batteries (one of the two is a car battery which I'm going to replace with a deep cycle type anyway) be causing the problem? Lesson learned, I suppose - always recharge the batteries during the week...<br /><br />Also, is there any collateral damage to watch out for from my latest lake mistake?

 

[SS MAYFLOAT]

Re: Batteries dead - running rough after jump start

Sounds like your alternator/regulator is not operating correctly. Your taking out power and not putting anything back into your batteries. It is also possible that you may have a bad battery. Are you running on just one of the two batteries? or both? If you run on both, that may be your problem. Your alternator is not designed to charge two batteries at once. <br /><br />The reason it is running rough is because: Low voltage=weak spark=poor performance. There isn't enough spark to burn all the gas that is going into the cylinders.<br /><br />Put a volatage meter on your battery while it is running (make sure your muffs are on) Your voltage should be between 13.5 to 14.5 volts dc. If you don't get that voltage, your alt/reg needs replaced.<br /><br />Good Luck

 

[LubeDude]

Re: Batteries dead - running rough after jump start

Also if you are running on both batteries at the same time, they should be a matched pair, a common mistake. Yes your alternator can charge BOTH batteries at one time if hooked together.

 

[rufnek100]

Re: Batteries dead - running rough after jump start

They are hooked up in parallel when running, but separated by a solenoid relay when the key is off. This is to keep one battery isolated while anchored to run the amp/stereo so there's always enough power to start the boat. <br /><br />I thought that the different batteries might be a problem. One of the batteries is a marine combo deep cycle/starting and the other is a common car battery. When matching the pair, is it acceptable to use a deep cycle/starting battery in conjunction with a straight deep cycle battery? It seems like the pure deep cycle batteries have longer reserve times to run the stereo, but the high amperage would be nice when starting; although, I don't want to compund the problem if that kind of a setup isn't sanitary... (I've got a 700W 5-Ch. amp that probably draws a lot of power).<br /><br />If the batteries need to be matched, what's the best setup for what I've got (two deep cycle, two combo starting/deep cycle, etc.)?<br /><br />Think I fouled the plugs? I guess there's only one way to find out...

 

[LubeDude]

Re: Batteries dead - running rough after jump start

I would use two deep cycle starting, But there is something else to concider. With the batteries hooked the way they are, if you run the other battery down with your stereo and other accesories, and then try and start your engine, the power from the good battery is going to drain into the dead battery in short order. You need a complete isolation system, then you could have one deep cycle starting, and one regular deep cycle for your accesories.

 

[rufnek100]

Re: Batteries dead - running rough after jump start

Thanks for the advice LubeDude. I'll try another combo battery with the one I've already got and see how it works...