Deep cycle marine battery

[Danielb]

I've purchased a new deep cycle marine battery
I'm running a dual setup on my boat
After ive connected everything, it's all working fine the next time I go to start the outboard the starting battery is completely dead "dropped cell" I returned the battery and got a new one and the exact same.thing happened it also dropped a cell. Would any one have an idea? Could it be a faulty isolator switch

 

[James]

Can you draw a diagram of how it is all connected?

 

[JBW175]

What type of boat, a rib? Could be a heavily corroded isolator, or a corroded connection somewhere on the outboard that needs cleaning up, normally on the neg where the starter motors bolted to the engine.

sea waters a killer on most things, gets into battery compartments and rots everything.

I’ve seen that many knackered batteries on boats over the years from it. In the end we’d either disconnect the battery at the terminals, or take it out completely when not in use.

Get a lot of problems with electrolysis between dissimilar metals on boats too. How’s your sacrificial anodes looking? They’ll need changing if over 50% warn.

 

[DPG]

Lucien is your man for this I reckon.

 

[pirate]

We need more information on the type of boat, exposure to the elements etc. and isolation details...a dropped cell isn't that common these days. What type of battery is it? If it's a RIB with the battery in a "box" it is more prone to harm than in, say, a cruiser, where the batteries are typically well inboard and not exposed to the weather.

 

[Timbo]

Lucien is your man for this I reckon.

Best to tag him in, then.
Hello @Lucien Nunes can you help?

 

[DPG]

Best to tag him in, then.
Hello @Lucien Nunes can you help?

Good point, thanks!

 

[PEG]

Hi,if that was the diagnosis on two consecutive batteries,and they were the same,i would suspect cheap batteries.....as in cheaply made,not cheaply bought?

....unless the time scale between all these incidences is many years....

 

[EricMark]

Does the outboard charge the battery? I know the one my did bought did not charge the battery, had electric start, but no charging.

Outboards often have a very low charge rate, where inboard my son had 2 x 70 amp, so much depends on the outboard.

 

[PEG]

A tilley lamp.MSR stove and oars,solve a lot of these problems...?

 

[DPG]

A tilley lamp.MSR stove and oars,solve a lot of these problems...?

Can't beat a night out with a couple of oars!