205 Sport battery issues

Fattom

New Member
Aug 21, 2017
9
Boat Info
2007 205 Sport
Engines
Mercury Mercruiser 5.0
New boater and had some issues with our boat this weekend.

This is our 5th or so time taking the boat out and we have had no issues before. Wife was in the boat when I went to launce checked to make sure the bilge was on and I thought she had started it and everything was ok.

Reversed in the rest of the way and the boat wouldn't turn over... Poor thing was just out there floating. Luckily she floated to the side of the ramp and a guy was launching and brought over jumper cables. Finally got it to start and we decided to ride around to try and "charge: the batteries. The reading wasn't going over 12 and anytime I moved the trim up or down it beeped and would drop to 10. The speed pass would beep when I hit buttons but wouldn't turn on.

Radio and gauges all worked. After about 45 minutes we went back to the ramp and put it on the trailer. Turned her off and wanted to see if she would start again and nothing.

We last took it out a couple weeks ago then went on vacation. Could the batteries have died that fast sitting in 110 degree central texas weather? We haven't had any other issues with it.

Looks like 2 27m6 Deka Marine Master batteries running together. Any help would be appreciated. Her son is turning 10 this weekend and want to get out on the lake.

IMG_1148.JPG


IMG_1149.JPG
 
Sounds like your alternator is not working/charging. Also need to clean those battery terminals... should not have any green stuff! Check all connection points.

With two batteries, I assume you have a battery switch?
 
That's the interesting part I think the previous owner just chained them... I don't see a battery switch on the console anywhere.

Should I go get the batteries tested? Or take it to my local repair place
 
Have you checked the water levels in the battery?
Keeping them full of water is critical to their life span. The fact that the battery did not charge could mean the alternator is dead or that the batteries have been fried and will not hold a charge.

If you have a battery switch, turning it to the OFF position while away from the boat will help save the battery's life. Things like the radio's display will draw power while away from the boat and drain the battery.

Load testing the batteries is the easiest thing, if they're OK then the alternator is next.
 
Guess after work I'll go to the storage yard pop out the batteries clean and take them to get tested
 
I don't see a battery switch on the console anywhere.
If you have a battery switch, it will be somewhere near the batteries... will be a large (up to 3") four position rotary switch. Most of them have OFF, 1, 2, or BOTH positions like this one:

battery switch.jpeg
 
That's silly why would you put it way back there under the seats
 
They put them as close to the batteries as possible due to cable runs. Longer the run the heavier gauge cable you need. Mine is on a partition wall dividing the battery area from the engine/bilge space.
 
Be certain that the serpentine belt didn't break. The boat will still run without the belt but power steering, alternator, and circulating pump won't function. Then the battery will die.
 
So at the boat right now and there is a switch it was on both...

Either way I turn the key to the left and the radio and humminbird depth finder come on... to the right gauges, perfect pass, radio, and a loud beep. Bilge blower sounds loud and strong...

Any thoughts? Should I take it to the ramp and see if it starts?
 
So when it would not start, it would not crank at all?
You can try the key to see if the motor will crank for the briefest of time out of the water. If nothing, likely not the batteries but the main engine breaker.
 
Check the connections on both batteries - I don't like the way one battery is grounded through the other one. It will work, but it's best for each battery to have a Pos and a Neg cable running to the battery switch.

If you have a battery switch and two batteries, you should have a 1, 2, Both position. A lot of people mistakenly leave the switch on both thinking it will always charge both batteries and you will have both batteries available for cranking. This works fine until one battery starts to fail, then it brings the charge on the good battery down / equal to the charge on the bad battery - and now you have two dead batteries.

You probably have one bad battery - put a volt meter on both, figure out which one has the best charge (< 11v is pretty much dead) and set the switch to that battery, get the boat started and let it charge that one up. After it's running put a volt meter on the batteries, the one you are switched to should see 13-14volts, same as on your dash gauge.

Keep the switch on that battery until you replace the other one or charge it (you could charge it by switching to that battery once the engine is running - but never switch it to "Off" while the engine is running).

Once you have two good batteries in the boat, alternate between Bat 1 and Bat 2, or switch between them using one for a starting battery and one for a house battery. Only time I use "Both" is on a long run to charge both batteries, or if both were somehow run down it combines the batteries for "emergency" starting.
 
So when it would not start, it would not crank at all?
You can try the key to see if the motor will crank for the briefest of time out of the water. If nothing, likely not the batteries but the main engine breaker.

Roger it wouldn't crank at all. I was able to crank it today. I hope I didn't break it
 
Check the connections on both batteries - I don't like the way one battery is grounded through the other one. It will work, but it's best for each battery to have a Pos and a Neg cable running to the battery switch.

If you have a battery switch and two batteries, you should have a 1, 2, Both position. A lot of people mistakenly leave the switch on both thinking it will always charge both batteries and you will have both batteries available for cranking. This works fine until one battery starts to fail, then it brings the charge on the good battery down / equal to the charge on the bad battery - and now you have two dead batteries.

You probably have one bad battery - put a volt meter on both, figure out which one has the best charge (< 11v is pretty much dead) and set the switch to that battery, get the boat started and let it charge that one up. After it's running put a volt meter on the batteries, the one you are switched to should see 13-14volts, same as on your dash gauge.

Keep the switch on that battery until you replace the other one or charge it (you could charge it by switching to that battery once the engine is running - but never switch it to "Off" while the engine is running).

Once you have two good batteries in the boat, alternate between Bat 1 and Bat 2, or switch between them using one for a starting battery and one for a house battery. Only time I use "Both" is on a long run to charge both batteries, or if both were somehow run down it combines the batteries for "emergency" starting.

Went through today and tried both 1 and 2 they worked the same... gonna take a volt meter later this week to test them.

I turned it to off, once I test the batteries I will use the strongest to start it and when we anchor use the other for the radio.

So I can switch between 1 and 2 with the motor on just not to off?
 
With the engine off, you can move the battery switch any way you want.

With the the engine running, NEVER move the battery switch to "off". This can cause immediate damage to the electrical system.
 

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