Battery Types?

colobear · Posted: Fri Aug 23, 2013 11:42 am Post subject:

The engine alternator puts out a certain charging amperage when running and sends that, minus the electrical power needed to operate the engine, to the battery. There is often a battery controller of some kind in the circuit to prevent overcharging but if you run the engine for a few hours the battery will likely be fully charged. A battery will slowly discharge while connected to the boat circuit so many people keep their battery on a trickle charger while the boat is out of the water and then start with a fully charged battery. We use a solar panel to keep C-Cakes batteries charged between trips.

thataway · Posted: Fri Aug 23, 2013 2:38 pm Post subject:

Grazer · Posted: Fri Aug 23, 2013 11:45 pm Post subject:

After reading the latest addition to this thread, I realized it was mine. Good time too. After having the boat at a Marina for the past two months without additional shore supply my '03 Honda 90 (16 amp output) kept the batteries up all summer. The runs were long enough to charge up fully at the end of the day and my draws were minimal. When I got home, l plugged the charger (ProSport 12) in and within approximately 20 minutes the batteries were ready and both at 13.42 V. So it would seem using two slightly different lead acid batteries (one AGM and one standard lead acid) with the dual bank charger works well.

Cheers Beer

,
Grazer

Stan Major · Posted: Sat Aug 24, 2013 6:46 am Post subject:

Thanks for the help in the replies. I did purchase a Battery Tender trickle charger but have yet to try it.

potter water · Posted: Sat Aug 24, 2013 10:41 am Post subject:

Battery disconnect switches are a great invention. Typically, we will shut off both start batteries and the house battery when we are not on the boat unless we will be off for only a few hours. I've yet to actually need shore battery charging. However, during the off season, I remove all three and keep them in the garage and put them on a full automatic charger once every month. Other than that, they don't see shore charging. Every thing seems to work fine with that protocol.

potter water · Posted: Sat Aug 24, 2013 10:43 am Post subject:

Battery disconnect switches are a great invention. Typically, we will shut off both start batteries and the house battery when we are not on the boat unless we will be off for only a few hours. I've yet to actually need shore battery charging. However, during the off season, I remove all three and keep them in the garage and put them on a full automatic charger once every month. Other than that, they don't see shore charging. Every thing seems to work fine with that protocol.

Foggy · Posted: Sat Oct 12, 2013 10:19 am Post subject:

Powerboats have engines with alternators and batteries to charge. So do automobiles. Why do boat batteries require shore power, or other, extra charging to be topped off to a full charge and not automobile batteries?

Just wondering...

Aye.

Foggy · Posted: Sat Oct 12, 2013 7:31 pm Post subject:

Hey there, Foggy, no bites on this one?

Let me give you my 2 cents worth:

I think it's because auto batteries, maybe the original 'starting battery', has mainly just one job: provide high amps over a short time to start the engine. Once the engine is running, the engine alternator provides all the autos power needs: light, horn, gauges, GPS, cell phone chargers, etc. These batteries usually are not run down past 20% or so. This, plus their physical make up of multiple relatively thin lead plates in acid lend them to being adequately recharged by the engine alternator.

Marine batteries, as I see it, are different. Boat electrical needs are often high when the engine is off, unlike an auto - unless one plays the radio too loud too long and then finds the thing won't start. Been there. Enter the 'deep cycle' battery which is designed to meet long hours of draw down. Most don't take much past 50% draw down without shortening their lifespan. AGMs may stand 80% draw down without suffering much as long as they are recharged. Deep cycle batteries have much heavy lead plates than auto starting batteries - notice they weigh more? This physical difference in the plating relates to the need for longer charging at lower voltage than auto batteries. Of course, there are 'combo' starting and deep cycle batteries which split the characteristics, and charging needs, for the auto and marine types.

That's my story and I'm sticking to it.

Aye.

thataway · Posted: Sun Oct 13, 2013 9:44 pm Post subject:

Certainly agree with Foggy's reasoning. An interesting thing is that my 2012 Yukon only runs the alternator if the battery voltage drops or the power draw is increased. The idea is that you will get better mileage with less alternator draw. (I have not gong into the electronics of this), but it bothered me enough to put a SCAN gauge on, so I could monitor the battery voltage. It runs form 12.5 up to 14.1. So this affirms Foggy's thoughts, that even with an alternator which does not run all of the time, you are on the top 20% of the battery.

In a boat which runs a lot of the time, the battery will be charged--maybe even over charged if there is a poor voltage regulator. The inboard-inboard/outboard will have a "smart" regulator. When you are on passage with a trawler--the batteries are always charged, as the car. In a passage making sailboat--just the opposite, where the battery banks are drawn down to 50% by autopilots, nav gear, radios etc--and then a generator is used to bring those batteries up to charged state, heat water, make water, bring down eutectic solution in freezer/refer plates and may even do the wash. by running several hours a day. (I know some boats still use wind vanes...and no power to steer--been there)