96 Speedster - Batteries in Parallel?

[chansman43]

Rather than have 1 big battery, has anyone put a cable between the positive leads on the twin battery setup to put them in parallel? There is already a cable connecting the negative terminals. Is there any issue in doing this? Seems it would be electrically the same as having 1 battery.

 

[jmdotso1]

Yes you could put the positives together which would put the batteries in parallel increasing the total amperage of the system. While this is the simplest way to increase capacity for running equipment such as stereos longer and providing more current when starting an engine it does have some downfalls. If one battery becomes worn, damaged or drained the other battery will try to equalize the load and be drawn down as well or if you drain your entire bank running an amplifier you will have no reserve remaining to start your engine. A better way is to install a battery selector switch providing a 1, 2 or BOTH option for the battery being used. This also allows for charging the batteries independently, easier troubleshooting and provides a way to run house loads (stereos and such) off one battery while at the beach and having a reserve battery to start the engine. Then once you're engine is running switch back to the low battery and allow the engine to recharge it.

 

[unclejay]

Dont Do It

Dont do either of the above. There are 2 separate electrical systems with a comon ground wire, if you fool around you could short the MPEM (Multi Purpose Electrical Module) which is almost impossible to replace and totally disables the boat.

You can put 1 battery in, many owners have done that. I dont see any reason to since there is a crossover switch at least on the 95s.

 

[parrothd]

Replace the 2 single batteries with a large marine battery, plenty of write ups on it, combining the 2 small batteries will only improve your cranking power a few percent. The Large single marine battery gives the best power and longer..

 

[parrothd]

Also,

If you have a 95 speedster you should have the switch that combines the batteries on the console, no need to re-invent the wheel..

 

[chansman43]

Also,

If you have a 95 speedster you should have the switch that combines the batteries on the console, no need to re-invent the wheel..

I do have the COMBINE switch but it does not seem to be working. Something else for me to troubleshoot. Great replies all. Thank you.