New Starting Battery

[Paulus]

I need to replace my starting battery. How many cranking amps(cold) should I have for my Universal engine?  What are the rest of you using?
Thanks,
Paul

[TonyP]

Paul
Ours is a Amaron Pro 95A/h zero maintenance ... not sure what the cca is.
We also have 2 of the same for the house, so all 3 when cranking the motor.
I will get bigger house A/h when these ones fail though.
cheers
Tony

[Ron Hill]

Paul : I wouldn't worry about cold cranking amps - after all you've only got a 23 hp engine.  It's not like your large auto 200 hp engine!  Just get a group24 starting battery.

If your starting battery is in a location that not easy to get to, get a maintenance free.  It's best to also have it the same type as the rest of your batteries gel/AGM/flooded.

A few thoughts

[waterdog]

I have an Optima yellow top buried under the aft.   Always ignored.    Never maintained.   Performs flawlessly.   

[Paulus]

I had a Everstart Maxx from Walmart.  Buried under aft. Has performed flawlessly for 7 years.  Never removed in the Michigan winters.  Tried to charge it but no luck.  I think the cold finally killed it.

[stevewitt1]

Hey all.
I know I'm about to get blasted for the "dumb question" of the month, but I'll ask anyway.  Why do these boats have a "starting battery?"  When I bought my boat the PO referred to the starting battery.  I replaced all three.  There is a battery switch OEM on the panel, then an added one inside (not the most convenient but I guess out of the way) under the dinette just forward of the galley for bat 2 and 3 which is located under the starboard seat of the dinette.  Bat 1 which appears to be #1 on the OEM switch is also referred to as the starting battery.  My diagnosis seemed to show, OEM switch in pos 1, goes to the 8D/starting bat, switch pos 2 goes to the second switch.  This seems to control all DC items in the panel but even with all in Off pos,  the engine still turns over.  The mystery is that there is only 1 cable attached to bat 1 + terminal.  I figure the starter is wired to the hot side bat 1 on the OEM switch.  I wired my inverter to the + & - directly on bat 1 (8D)

The dilemma that I want to avoid this season is that when anchored out (I'm too cheap to pay transient fees) and I run my inverter the engine shows low voltage in the morning.  Switching to bat 2 on the OEM doesn't change voltage at the engine panel. Switching to both brings it up. (but now I feel I'm just using the switch as a jumper through the 8D)  I'm thinking of putting an Optima under the aft or on the shelf as others for starting but then I will have to configure a charging circuit, correct?  I could use an isolator but don't like the voltage drop through the diodes.

What am I looking at wrong? 

OK, time to beat me up.

Thanks in Advance, be gentle as I'll be back for lots of help this spring. (still snowing here north of Green Bay)

Steve

visit us at www.ocontoyachtclub.com and www.warbirdsix.com

[TonyP]

Steve
The way I read your question is your "starting/engine" battery is there for you to start your engine when you have run down your house bank. The way you described yours,I feel ours is wired the same. I often forget to turn off the engine battery switch (ours in in the head under the sink inside the door) and with our old original fridge/freezer running, it does drag down the two house batteries overnight. If I do forget to turn off the engine battery they don't run down as fast so instead of running on our 2x95ah house batteries it is running on 3 x 95ah batteries. As soon as these batteries start to fail, I will be updating the ah size for all 3. Even though we have a couple of solar panels they would only trickle charge the batteries so have to run the engine for a couple of hour per day to keep on top of them. I believe ours is set up that each of the house batteries is battery 1 and 2 and both with the engine battery only in line if the separate isolation switch is in the ON position.
Only late afternoon here so others will add their input as they come on line as their day begins
cheers and good luck with it
Tony

[Jim Hardesty]

Steve,
No question is a dumb question.  Expecialy when it comes to batteries and boats.  Everyone has a well reasoned idea.  Can be confusing.  My well reasoned idea is that the right battery bank has to do with the way the boat is used.  The factory setup works well for me.  I'd add a starting battery and change the bank if I often stayed at anchor or mooring for days at a time.  Or under sail for days at a time.  A dedicated starting battery is like a car battery, lots of cranking amps, soon used, and will charge quickly.
Know what your system will do.  If you often do something differnt, then think about changing it.
Jim

[DaveM]

I use a group 24 with 650 cca from West Marine on a Universal M25XP and it does fine.

Goodwinds
DaveM

[Stu Jackson]

Steve, it all depends on how it's wired.  I created the "Electrical 101" topic within the "101 Topics" sticky, to gather the kind of information you need to answer your question.

You might be interested in these threads, and then do some wire tracing and wire diagrams on your boat.  The concept of a "start" or "reserve" bank is discussed.

Basic Battery Wiring Diagrams  This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html

This is another very good basic primer for boat system wiring:  The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615

There are many options, and it all depends on how you want to use your boat.

There's a lot more electrical system information in that "101" topic.

[mregan]

I thought the purpose of the starting battery was to use only for the engine.  If the house batteries were drained down, the starter battery would be un-affected so the engine could be started if need be.  I have mine wired this way.  I like knowing I always have a full battery to start the engine just in case I run the house batteries down too far.

Not to hijack the thread, but if the batteries are too drained down to start the engine, if I hook up a Honda generator to the shore power plug, will the engine start up right away or do the batteries need to charge first?

[Stu Jackson]

There are two schools of thought about "start" or "reserve" banks.

One says use the house all the time and keep the other in reserve.  The other says to use the start to start all the time.  The different wiring diagrams in the Electrical 101 link discuss them both.  You can also use the single 1-2-B switch to use the reserve to start all the time.  If/once you relocate the alternator output from the C post to the house bank, you can move the switch positions with the engine running with no fear of blowing alternator diodes.  Your boat, your choice.

To your second question, the answer is yes.  Once the generator is connected and the charger is on, the voltage will  go up and you can start.  Shouldn't be any reason to get to this condition unless both banks have died or the house bank has and you've made the mistake of using BOTH, which will drain what's in the good reserve bank into the dead house bank.  That's why many of us don't like the Blue Sea Dual Circuit switch concept for sailboats.  That's covered in detail in the "Darn AGM" thread in the Electrical 101 posts.  That's also why it is important, I believe, to have a switching system that allows you to use either bank to start or to run the house without using both together.

[Ron Hill]

Guys : Just remember that "even in reserve", you are obliged to exercise (use) a battery - especially a flooded battery!! 

A thought