Cranking Battery selection

CnC

Wondering what cold cranking amps I need (or even how important they are?) Or "how" they come into play when choosing cranking batteries? I'm going to replace both mine with new and need some advice? Strictly cranking , do marine batteries even come this way? Cranking/Deep cycle combination??? At this point I can't afford the super expensive types or specific brands so I'll probably go to Canadian tire for them and will replace all (cold cranking and deep cycle) with the best available when I have the money to do so. Also on the list is a decent Ronca anchor to replace the CQR that slipped out and sent me close to shore while I was below deck for a bit. Anyhow any and all help appreciated
Thanks so much
Cliff

YYZRC

The cheapest version of the Nautilus battery will be just fine.  I run group 27 for starting and group 31 for house.

Group 24 Starting (1000 marine cranking amps)
https://www.canadiantire.ca/en/pdp/motomaster-nautilus-group-24-starting-battery-1000-mca-0102495p.html

Group 27 Starting/Deep Cycle Combo (800 marine cranking amps):
https://www.canadiantire.ca/en/pdp/motomaster-nautilus-group-27-starting-deep-cycle-battery-0102799p.html

Aqua_Aura

Get your old batteries tested it should be free. It would be peace of mind to know that your old batteries are indeed bad so you know that if you have problems after the new ones are installed it should cross off the battery being the issue. 

CnC

I have a load tester Aqua, is that what you mean?

Aqua_Aura

I would let them test it. They should have a fancy battery tester that does a much more in depth test. It shouldn't cost anything. 

CnC

So are the engine batteries exclusively for cranking the engines or are there other accessories utilizing these as well such as bilge and fridges? 

Aqua_Aura

Engine battery should only be for the engine and house should run everything else. I'm sure the engine may run some consequential stuff related to starting the engine and running it but not house type accessories 

CnC

Please be patient with me here guys regarding this battery thing but I have another question if I may? I changed out the two cranking batteries simply because of the dates stamped on their  decals. The deep cycle are a touch newer but being this late in the season (and budget) I'll change those out in the spring. My question is "are all 4 of my batteries being charged by the on board charger while I am on shore power?" Or, do the house batteries "only" receive the charge and cranking get theirs from the alternators when the engines are active? Reason  I'm asking is that when I'm on shore power with both batteries "OFF" only the cabin fridge runs and not the cockpit fridge until I turn on the engine batteries? Not sure how much draw a fridge takes but couldn't it be enough to be a concern when we are off shore power and maybe only doing short runs and then stopping? If it is the alternators "only" charging the engine/cranking batteries paired with short runs (hence very little in the way of re-charging?) doesn't it make sense that a fridge and whatever else might prematurely lessen battery life? Sorry, electrical is not a strong point of mine

YYZRC

If the charger is working properly, and assuming no previous owner modified the electrical system, all batteries will be charging when on shore power or while the engines are running.  If you're not seeing charging when the engines are running, it could be an issue with your isolator.

CnC

You are going to think I'm a complete idiot here and I'm sure I already know but this is what you're referring to right? Not some little box or switch hidden in a closet or in the engine compartment right?

YYZRC

No, the isolator is probably located on the firewall near the charger.


https://images.app.goo.gl/9HU7Y6YGMCfwD5iB8

Pat310

We are all here to help each other so no don’t be shy about asking. That is the battery selector switches. The isolator is in the engine compartment near the battery charger. 
Black box with red wires running to it is the isolator on my 310

CnC

How can you tell if it's caput? I wondered what that thing was?

YYZRC

If your alternators aren't charging the batteries, either the isolator or the alternator(s) could be faulty.

I think you need to do some more investigating around the cockpit fridge - it seems unlikely that the fridge would be wired to one of the engine batteries, but if it is, that is not prudent and it should be wired back to the house battery bank.

Spyderweb

"...with both batteries "OFF" only the cabin fridge runs and not the cockpit fridge until I turn on the engine batteries?"

Is there any chance the cockpit fridge is DC Only"?

Aqua_Aura

It seems like it is DC only however it still shouldn't be running off engine battery. Maybe this was not factory installed and someone wired it to the wrong battery. 

CnC

Thanks to everyone with the advice so far, it is more than appreciated. Went to the boat yesterday to get my wife out of the house so the kids could decorate for her 50th and decided to do a short run to an island about 15 minutes away from the dock. We were almost there when an alarm sounded (the same one that signals briefly at pre-start). All gauges read normal so into neutral we went, dropped the anchor and lifted the engine hatch with the engines still running. The starboard side outdrive reservoir was empty? I'm assuming this is a closed system and wonder where the lines lead from that reservoir between it and the actual drives? Never noticed any leaking but at the same time wasn't looking either? Maybe a slow leak? The outdrive levels were checked by the surveyor a month ago and we're fine. Going back today and was hoping someone could give me pointers of what to look for before heading back there? Also another question, my bilge holds water like any other but the pump doesn't appear to have an automatic switch. I want to install a new extra pump with the automatic float switch and wonder if how I'm going to do it is a good idea and which battery to use? I plan to place it beside the existing pump and run it directly to a battery (depending on which anyone here recommends?) and install an online fuse so its switch has a constant power source. Or, is there a power bar somewhere in the engine compartment I should use?
Thanks again so much guys!!

Pat310

Check to see if you can see the model number on the bilge pump you have and look it up. Some have the float switch built into them. If changing and adding separate float switch use the existing wiring to power it so the switch at the helm can manually turn the pump on. If your not sure it is working most have lever on them to check if it is functioning or add water with a hose to see if it comes on. As far as drive reservoir the hose connects to the drive through the transom assembly. Check for oil in the bilge and see if there is an oil sheen on the water behind the boat and let us know what you find. Mine had a cracked fitting going into the transom and leaked into the bilge. If in the water its leaking from the drive.  Wish the admiral happy 50th!

CnC

Will do Pat thanks so much

CnC

So yesterday I managed to spare s little time to get to the boat. Trying to maneuver inside that mess it a challenge. Looks like there's lots of room until you try to reach anything lower than the flame arrestors. Anyhow turns out it ust the float switch. I cut the two wires leading to it, touched them together and on it came. Changed that out and it is working well automatically and at the helm switch too. There was an oily residue in the bilge but looked more like sludge from the past. Traced the line from the out-drive monitor to the transom and it looked daily clean and dry so my dear is that it may be external. Never noticed any residue but that could easily be hidden by the swim platform too I suppose? Anyhow, going to go this evening and replace the lost fluid in the reservoir, check it for leaks and cross my fingers that by some strange miracle it was always low and the surveyor missed it. 

CnC

Just to note, auto-correct is making me appear like I'm a complete low functioning imbecile so please pay it no mind. 

LaRea

Know worries, it happens too hall off us!  BTW if you want to edit something you already posted, go to that post and click the gear icon just above it near the right side.

Handymans342

CnC said:

Just to note, auto-correct is making me appear like I'm a complete low functioning imbecile so please pay it no mind. 

I thought it was translating from French to English.