Battery Questions

[Tarkus]

I'm carrying 2 batteries on board. A12V motorcycle battery to start my (yes I know...over sized) 9.9hp Honda 4 stroke and a standard 12V car battery for the boat electronics. Is there a problem since they're not marine batteries? This is what the previous owner had. Thx

 

[rpludwig]

Deep cycle group 24 Walmart $100, has served me well for 3 years with a trickle charger on it when not in use. Our electrical needs are minimal....couple fans, chartplotter, a few cabin lights, phone charger....ymmv. (oh, my outboard starter battery is my right arm....however weaking with age!)

There's a lot of battery discussion here on the forum...do a search here, and others will chime in as well....

 

[Don S/V ILLusion]

. Is there a problem since they're not marine batteries?

Generally, using a typical automobile battery is a problem as it isn’t designed to power anything other than the instantaneous starting of the engine. If you have electronics, depth gauge, radio, etc.. running, these will prematurely kill a battery not designed to power equipment. Get a good deep cycle battery and use your car battery to start the engine.

 

[Gene Neill]

What Don said. Except I'd continue to use the motorcycle battery for starting. Unless the motor has a pull rope for emergencies? In which case, I'd just use the one deep cycle battery. It will start that motor many dozens of times.

 

[greg_m]

I bought another old boat as mentioned in my SA Catalina thread. It had two batteries according to the seller. One turned out to be a dud although it was hooked up. The other one was infact a few months old before my purchase. The dud one was draining the good one so I removed the dud one completely.

On my boat I have reduced down to one battery. In my case my boat has a 2 cylinder inboard diesel - Sole Mini 17. The one battery is a maintenance free Calcium/calcium battery from Deltec with code SMF 24HCM-600.

When i took the battery to a battery specialist I was informed that this is in fact a deep cycle battery that is capable of providing starting current at the rate of 600 Amps! As my boat has pretty much zero in way of instruments, one old Garmin GPS/plotter and only essential nav and cabin lights my electrical demand is pretty close to zilch.

So I do not intend to supplement my battery situation with a separate starter battery. Of course my boat lives alongside, has access to dockside shore power if I need it. A 30W solar panel and basic mppt charger keep it topped up along with regular engine/alternator runs runs. I do keep an AC power battery charger handy should the need arise.

Read into the above = frugal budget for this boat!

I was very surprised by the battery expert to be told that this battery will do as a starter battery as well as a house battery. There is no hand cranking facility for my inboard so I'm pretty paranoid about electric consumption. Everything is isolated when I'm away from the boat.

 

[Leeward Rail]

A friend of mine uses a good quality automotive battery in his Tanzer 22. If it dies within 5 years he gets a new one for free. He does the same with his RV. He says he has always done this.

He uses leds for lighting and minimal power consumption, similar to our C22, so i assume this is a factor.
His sailboat battery is on it's 6 or 7th season.

According to the local battery rep, not all deep cycles are true deep cycles of good quality. When the automotive battery in our C22 dies, I plan on buying a Rolls Premium Deep Cycle but our 5 year old $90 auto battery is doing fine so far. ($18 per year at this point)

Personally i would use what you have and switch when they die.