Extra Battery

[TROUBLE]

My 43-dc has 2 -8d batterys. The stbd one is for the generator and the stbd engine start. The port one is the house battery and the port engine start. If I wanted to add two extra 8d's could I just connect them positive to the individual on-off battery switch and ground to the same side existing battery? Will the alternator and the on board charger handle them without isolating them or installing a 1-2 both switch? Boating season is pretty much over where I live and I am looking for things to do to the boat that dont involve too much brain damage.

Thanks as always,
Art

[Chad]

I have heard that mixing old and new batteries in the same bank results in shortened life for the newer battery.

[spartonboat1]

Interesting, as I thought that the 43DC's always came with 4 8D's; at least mine does, as others I have observed. Early years outboard of the mains, later years inboard. So you have only 2? What year is the vessel?

[SKYCHENEY]

Interesting, as I thought that the 43DC's always came with 4 8D's; at least mine does, as others I have observed. Early years outboard of the mains, later years inboard. So you have only 2? What year is the vessel?

Our 1975 43dc had 4 8D's, two on each side, outboard of each engine. What a pain to get to when you needed to add water......and even worse when you needed to change them out.

[Bill Allen]

Thia mornings project is changing out my 4, 8D'd as mentioned two to a side outboard of the engines. Requiring wrestling, pain and crawling and of course lifting all the hatchs. I modified my deck braces and can now crawl outboard of both engines without moving any hatchs, except to replace the batteries. By changing the brace by the genset and moving my water heater farther outboard it becomes just a crawl to check water and of course it gives me storage for oil and some parts outboard as well. Since I can now get there without moving furniture and hatchs it's no biggie. I did go to gallon containers of make up oil since it's still a pita moving 5 gallon containers back there. I also gainned better acces to the ac units by moving them. Bill

[TROUBLE]

The boat is a 1972 and a put the existing batteries in when i bought it in may of this year.
My current batteries are located just in front of each engine., between the water heater and engine on one side and the generater and engine on the other side. I would put the second batteries on the outboard sides of each.
Art

[REBrueckner]

If your existing batteries are the same vintage,and show about the same hydrometer (specific gravity) move one and parallel it as you describe to one side or the other with the other existing battery.

Then install two brand new batteries in parallel on the other (empty) side. It's a good idea to replace those pairs at different times...that way you are assured of always having one recent pair of strong batteries....no guarantee of course, but better than having all four batteries, say, four or five years old simultaneously....

One battery is probably ok for warm weather starts when everything is working fine...two batts are much better because if something is not quite right or when the weather cools that extra power is always nice to have....