1990 sundancer 270 da battery charging/layout

[Rapidroy5858]

Rookie boat owner here,thanks for any help or advice in advance!
I left my shore power plugged in when I put my searay up for winter in my barn with the thought that it would keep batteries charged.
Today I found a very heavy acid smell in the barn and the single battery on the port side was very hot,the 2 batteries on the sb side seemed fine.
I am trying to figure the battery charging
system and layout of the 3 batteries .
I have been trying to find a schematic of the battery wiring to figure out which batteries are for starting and which one is for cabin accy.
Is it a mistake to leave boat plugged in for winter? Battery maintainer a better idea?
When plugged in are all 3 batteries supposed to charge?
Thanks!

 

[Cocktail Time]

All three should charge and the important question is the charger the original? The original units are notorious for cooking batteries and you need to check the water level often. There isn't an issue leaving the boat plugged in. A battery maintainer or upgrading to a "smart" charger might be a better option. Great boat btw. I had a '91 270 as my first Sea Ray and loved it. Mine was the single 7.4 though. I added a genset and ac and know the boat pretty well, if I can help answer questions. Best- Dan

 

[Rapidroy5858]

Thanks Dan, I have no way to know if it's original, also as I have read more about battery charging and the system in general I realized I have never checked battery selector switches. I will have to go out and check what position they are in.
My main concern is what each of the 3 batteries do.
Do you know if the switches need to be in the on position for the batteries to charge?.

 

[Cocktail Time]

Take a picture if it isn't too difficult. The switches on mine did not affect charging with the charger. But, there are about a million ways to set up the batteries and everyone has an opinion on what's best. A long time ago I found an article in a West Marine catalog that went over battery charging and it was really helpful. It is on their website. Do you have a genset? On most setups including my old one, there were two banks, one for house (two batteries) and one for starting, but then I had a single engine. I think I still have the wiring schematics, let me see, they might have both twin and singlr setup.

 

[MonacoMike]

And sometimes it is set up two house/start and one generator. You never really know what may have changed on a boat that age. Run the wires and see where they go.

MM

 

[Rapidroy5858]

No gen. Looked at switches,
One switch has the one/both/two/off
Other one is on/off
Checked batteries the 2 on port side were 12.8 and 12.5 seems they were getting charged.
The single on at was 11.6 and was also the same one that was hot this morning when I unplugged the shore power cord.
Seems like the 2 on port side were maintained as they should be by the charger.
Not sure why sb side was hot/ cooking.

 

[techmitch]

No gen. Looked at switches,
One switch has the one/both/twp/off
Other one is on/off
Checked batteries the 2 on port side were 12.8 and 12.5
The single on an was 11.6 and was also the same one that was hot this morning when I unplugged the shore power cord.
Seems like the 2 on port side were maintained as they should be by the charger.
Not sure why sb side was hot/ cooking.

Check the water level in all batteries and if necessary top off with distilled water only.

 

[Bt Doctur]

Hot, smoking, smelly acid smell all indicate a bad battery, bad cell(s) ,high charge rate, and YES batteries do just explode. A fully charged battery in the fall should have enough life in it to start a motor in the spring. If not, it`s junk. Good batteries do not constant charging.
Are the batteries flooded, gel. or agm or some other type? It matters to the chargers used .
With a twin you should have 2 independent charging system, check that first. You should also have dedicated engine batteries that only work the engines, nothing else.A 27 footer should have more than enough room for 2 deep cycle, golf cart batteries (4) , or a large diesel battery only for the house.
Wire your battery switch`s 1/BOTH/ 2 That`s right 1 switch for each engine. Use #1 for engine starting for both engines , easy to understand. A jumper between the #2 positions and another jumper to the house on-off switch.
Should the need arise "both" "both" "on" gives you all the batteries to start atleast 1 engine to get home on. Another option is to add a battery to the #2 post. This gives you another battery to add to the system for starting "both" , "both" ,"on" uses all 4 batteries .
And if you manage to kill all the batteries ,you need further instructions

 

[Rapidroy5858]

They are flooded bats, new last year by previous owner.
I dont see anyway to add water, no caps or plugs. Putting maintainer on each battery for winter,
I'm concerned the one battery that cooked is likely trash, charging it then doing a load test.
Does each engine typically have it's own battery? It confusing looking at it.
Probably just going to keep them charged for winter and figure it out in spring.

 

[Sea ray sam 27]

All three should charge and the important question is the charger the original? The original units are notorious for cooking batteries and you need to check the water level often. There isn't an issue leaving the boat plugged in. A battery maintainer or upgrading to a "smart" charger might be a better option. Great boat btw. I had a '91 270 as my first Sea Ray and loved it. Mine was the single 7.4 though. I added a genset and ac and know the boat pretty well, if I can help answer questions. Best- Dan

Hello
I have a 1996 - 270 She has sat in fresh water all her life. I upgraded from the old "Black box" charger to a new smart charger. I keep her plugged in all the time, we live in TN. As stated, the water levels in the batteries must be checked, they will go down. I have never had an issue. One engine and no generator. I do turn the master switch to the off position every time I leave the boat.

 

[MonacoMike]

They are flooded bats, new last year by previous owner.
I dont see anyway to add water, no caps or plugs. Putting maintainer on each battery for winter,
I'm concerned the one battery that cooked is likely trash, charging it then doing a load test.
Does each engine typically have it's own battery? It confusing looking at it.
Probably just going to keep them charged for winter and figure it out in spring.

Unless they are Optma or other AGM batteries there is a water fill cap. It is often under a decal covering most of the top of the battery. It likely even says "sealed", to further confuse the matter.

MM

 

[Cocktail Time]

I found the info I got from Sea Ray a looong time ago. Looks like the schematic is original. It shows the diesel and single option layout but not twins.

 

[Rapidroy5858]

Battery on sb side cooked,appears to have overcharged . I decided to unplug the system from shore power and put float chargers on the 2 batteries that tested fully charged. Will address battery situation in spring. Seems odd 1 out of the 3 overcharged but anything is possible.

 

[Rapidroy5858]

I found the info I got from Sea Ray a looong time ago. Looks like the schematic is original. It shows the diesel and single option layout but not twins. View attachment 62420 View attachment 62421 View attachment 62422 View attachment 62423

Its similar to mine but without the 2nd switch and 3rd battery port side.
Thanks for the information.

 

[Rapidroy5858]

Hot, smoking, smelly acid smell all indicate a bad battery, bad cell(s) ,high charge rate, and YES batteries do just explode. A fully charged battery in the fall should have enough life in it to start a motor in the spring. If not, it`s junk. Good batteries do not constant charging.
Are the batteries flooded, gel. or agm or some other type? It matters to the chargers used .
With a twin you should have 2 independent charging system, check that first. You should also have dedicated engine batteries that only work the engines, nothing else.A 27 footer should have more than enough room for 2 deep cycle, golf cart batteries (4) , or a large diesel battery only for the house.
Wire your battery switch`s 1/BOTH/ 2 That`s right 1 switch for each engine. Use #1 for engine starting for both engines , easy to understand. A jumper between the #2 positions and another jumper to the house on-off switch.
Should the need arise "both" "both" "on" gives you all the batteries to start atleast 1 engine to get home on. Another option is to add a battery to the #2 post. This gives you another battery to add to the system for starting "both" , "both" ,"on" uses all 4 batteries .
And if you manage to kill all the batteries ,you need further instructions

Thanks for the try, looking at it I believe it's not been changed from factory wiring setup. I believe each engine has it's own battery for starting and the 3rd battery is for cabin, lights, etc? One battery fried on sb side, other 2 tested at 12.5 and 12.7 volts.