All About Boat Batteries

[NiceAft]

I am going to direct you to the thread "What lives in your anchor locker?". Specifically the end of Herschel's last post. Therapy may be in order? I know I am now leaning towards it.

[Neo]

My guesses is 72% is not the "Charge" is the "Depleted Capacity" ... in other words your battery is not charging up to full capacity any more.
I too wonder how a Learning Device would ever conclude that your battery is a "Basket Case" (new Aussie phase ) or "Buggered" (yet another new Aussie phase ) ... or Just plain Stu**ed

I align well with the "Ray method" ... I hate spending money and make that a life challenge .... But I also hate being adrift in the sea without any way to start my OB

Which reminds me I must get my Kicker OB installed some time soon

[NiceAft]

It was 29f last night (-1.6c). 32f (0c) this morning.

The batteries have not been charged for twenty-four hours. Yesterday the % charge was 72, this morning the % charged was 46%, with the house battery at 12V and the engine battery at 12.10.

OK mates, opinions.

[Jimmyt]

You've either got a connected load that is draining your batteries, or your batteries have gone eight legs up...

Without knowing how your boat is wired, hard to give you specific advice. However, I'd disconnect everything from the batteries except the charger and your battery meter, and repeat the test. If you have a good meter that will measure current, you can remove the negative battery lead on both batteries. Then, hold the negative cable on one battery and put your meter leads on the negative pole of the battery and the negative cable. Then, remove the cable from the battery post while keeping the meter leads on the post and cable, allowing you to measure any strange current that might be present.

I suggest touching the cable to the post while connecting the meter, due to the fact that some systems may have a brief inrush current when initially connected. If your meter can take 10-15 amps, you can probably just connect the meter and check it.

Conversely, you can disconnect your batteries and charge them. Then, let them sit for a couple of days and check the voltage.

[NiceAft]

First of all, I appreciate the interest of all who have contributed to this thread.

Unfortunately, it's to d8mn cold to work in the cabin, and the tarp does not allow light to see what I'm doing. This will have to either wait until things warm up, or I can get it to my mechanic to do his thing.

[Jimmyt]

Understand. When it gets below 40F here, I lose interest in outdoor activities. It will still be there when the weather warms up.

A good mechanic can check the batteries and find if you have a surprise drain somewhere. Several of the auto parts chains will check your battery if you ever feel like pulling them.

[Inquisitor]

Understand. When it gets below 40F here, I lose interest in outdoor activities. It will still be there when the weather warms up.

I'm thinking to us Southern boys, 40F is a totally different thing.
Have a Wisconsin buddy who wears shorts even into the twenties. I think he's got a screw loose.

[Neo]

Unfortunately, it's to d8mn cold to work in the cabin, and the tarp does not allow light to see what I'm doing. This will have to either wait until things warm up, or I can get it to my mechanic to do his thing.

Completely understand .... this might give you some time to "buy, steal or borrow" one of those battery testers I mentioned above

[NiceAft]

if you ever feel like pulling them.

No thank you

If memory serves me well (at 71, no guarantee), those batteries weigh 60lb each.

[Jimmyt]

I'm thinking to us Southern boys, 40F is a totally different thing.
Have a Wisconsin buddy who wears shorts even into the twenties. I think he's got a screw loose.

So true! I used to ride a motorcycle, and remember riding over to the beach for the view. There were snow birds there in shorts and bikinis playing in the freakin water. I had on a jacket and gloves and was trying to soak up enough sun to stop shivering. Had to turn in my man card...

[NiceAft]

I forgot to add in my last post; our snow potential by Wednesday evening is 11-18” (27.9-47.2centimeters).

[Inquisitor]

Obviously I'm changing the house side to Lithium, but I'm keeping the AutoCraft Deep Cycle Marine/RV battery (24DC-1) for the starter side. Its old... not like me old, but dog years yes. I wonder if you can help me diagnose if the battery is still something I can rely on. Here are some things I can state now, but if you need some other info, just let me know... I'll jury-rig any test you need.

• Besides being old, a symptom that makes me question it, and that I've already mentioned somewhere... is it seems to struggle starting the Merc 60. And a little more descriptive... it seems to struggle even on the first start, but doesn't seem to get worse even after ten, twenty starting attempts. It seems like my memory of batteries in cars going bad, will hit good on the first, but by second or third attempt they weaken and are gone by the fifth.
• A wise individual suggested to make sure the leads are clean and tight. I did on the battery side, but did not check the motor side yet. Too southern cold outside, so I took the battery out and its on my desk next to me in the warmth.
• I'm testing a fridge for the boat viewtopic.php?f=8&t=28046 and have this gizmo to test it
• Thought it might have significant info for evaluating my battery health. This is the data and everything I know. Don't know what bit is significant, so give all:
  • I did an Internet search, but it doesn't look like the current battery. One hit said it is rated at 75 - 85 amp hours.
  • I fully charged it, but don't really know when the start reading of 12.65 V was taken. Meaning... if I let it rest long enough after pulling the charger. How long is needed?
  • The test is a low current rate: Fridge pulls 2.4 amps when compressor is on, 0.09 amps when not. 62% duty cycle
  • Test is twelve hours in and used 18.74 amp-hours.
  • The voltage is down to 12.12 V whether the compressor is running and 12.24 V when not.

Doesn't this data permit some battery health evaluation... I've used some percentage of amp-hours and is this the voltage it should be at in its capacity run-down curve???

[Inquisitor]

... I used to ride a motorcycle, and remember riding over to the beach for the view...

Exactly which view are you talking about - the sand and sea and sky and clouds and sun and surf and gulls and....
or bikinis?

[Inquisitor]

I forgot to add in my last post; our snow potential by Wednesday evening is 11-18” (27.9-47.2centimeters).

Knock... knock... did you make it?

Years ago, a winter storm struck Atlanta with 1 inch of snow. It went clear right after the storm and went down into the teens, high never enough to melt off, just enough to refreeze into black ice every night and no road clearing services to speak of... totally shut down Atlanta for over a week. Many deaths were attributed to it.

Afterward the mere mention of snow in the forecast and the Mayor tells schools AND companies to send people home.

[Jimmyt]

... I used to ride a motorcycle, and remember riding over to the beach for the view...

Exactly which view are you talking about - the sand and sea and sky and clouds and sun and surf and gulls and....
or bikinis?

I went for the sand, sea, and sky. The winter bikini views are always a surprise - in one way or another - sometimes both . Surprised they are wearing a bikini in this weather; and/or surprised they are wearing a bikini...