Simple Auxiliary Dual Battery system.

Happened across a ad for a Dual Battery Isolator which keeps both batteries of a dual system charged up from the same alternator while keeping the batteries separate.
Running an PC-680 , on occasion I’ve had my sky-tech starter turn over slowly to the point of killing the battery and not being able to start the engine. Is there a way or has anyone installed one of these isolators along with a second battery and a manual battery switch so you can use one battery but always have a fully charged backup battery. There’s only about 100 hours on the sky-tech but I’ve ordered a new solenoid switch for it just in case the contacts are bad to cause slow operation. All the cables and connections are clean and tight. Also have dual P-mags so hand proping on a dead battery is useless. I know about the 9volt battery trick with P-mags but just don’t want to hand prop especially if stranded alone somewhere.

Which Sky Tech starter?

The lightweight Skytech is pretty weak unless you are using an EarthX battery. Many issues and pretty well documented. Good luck with the mods. A few I know just replace with an Earth X.

All you need for an isolater is another contactor and switch. Both on for start and charging.

Ed

Unless you are doing something weird, two batteries in parallel on a single alternator work well.

While I agree being able to split them out (i.e. master solenoid for each) to separate busses is a good backup mode, having them in parallel for normal operation is simple and effective. Both of my PC-625 batteries are on line for engine start and for all normal operations. One bonus is I do not have a panel brown out problem when cranking the engine (IO-360 or IO-540).

Carl

Does the type of battery matter (drycell, Lithium)?

I’m planning a dual battery setup - each with a separate contactor and switch. I’ve already purchased a PC680 and am looking at a smaller aerovoltz or earthX that will fit better on the firewall and add less weight. Is there anything with the lithium battery management systems that will cause me trouble?

When the alternator is off line, lead acid and lithium batteries should NOT be connected in parallel.
A lithium battery must be big enough to accept the FULL output current of the alternator without damage.