Dedicated Start Battery?

[jsalley]

RC --

I'm planning to reconfigure the DC supply side of my boat, a 2012 Catalina 355. Current setup is OEM: two independent 4D flooded batteries, through a 1-2-B switch. I have already installed a Blue Sea ML ACR, and MRBF fuses. I plan to add a separate Group 27 reserve battery, parallel the 4D's as a single house bank, and rewire the alternator directly to the house bank. Which brings me to my question: I added radar to my Raymarine electronics, but find that when I start the engine with the radar on, the scanner shuts down, and I have to reboot both the radar and the plotter to get it back on. Is there any down side to running the starter directly from the Group 27 (which would no longer be a true "reserve" battery), and activate the currently unused start isolation circuit on the ACR? I should still be able to manually switch the engine to the house bank if the start battery bites the dust. Thanks as usual for your help.

 

[Stu Jackson]

John, didn't Jon Vez do a writeup on electrical systems on the C355 Google group? I don't recall if he did a separate circuit for the issue you're describing.

Here's how to do what you want to do:

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

As we've mentioned, the C34 website is always available for you guys with those great new boats!

 

[jsalley]

Stu --
Thanks for the links - already aware of them (I had rewired my previous boat as described in the links, but didn't have the electronics drop-out problems with the Garmin system on that boat). My question (or maybe what I'm really looking for is validation from someone with expertise!) is whether there is any downside to using the smaller Group 27 as a dedicated starting battery, rather than solely as a backup reserve battery. I believe Jon has his system set up as your links describe, as well, using the Group 27 as a reserve.

 

[Doug4bass]

Just curious if you're starting the engine off off the house bank (4ds) , or the gr 27.

 

[Stu Jackson]

Stu --
Thanks for the links - already aware of them (I had rewired my previous boat as described in the links, but didn't have the electronics drop-out problems with the Garmin system on that boat). My question (or maybe what I'm really looking for is validation from someone with expertise!) is whether there is any downside to using the smaller Group 27 as a dedicated starting battery, rather than solely as a backup reserve battery. I believe Jon has his system set up as your links describe, as well, using the Group 27 as a reserve.

John, using the 27 as a start battery to avoid electronics dropout is just fine. The links describe BOTH ways to do the wiring (i.e., Option 2 in the first link).

 

[Solstice]

Hi John,
I do have my system setup as Stu describes. As Stu says, no issue with using a dedicated Start, however I would be curious as to why your electronics are dropping out, or let me rephrase, why there is not enough battery capacity to create the situation. Are the batteries OEM? If so, they would provide 320 AH (when new), which should be plenty.
I realize the OEM batteries are crap, but I am just starting Season 5 and should be able to squeeze this season out of them. My resting voltage is 90% from when new, so I feel I've gotten my money's worth out of them. I can start my engine with all instruments on, no problem.
I do plan on either moving away from the 4Ds if I can figure out a way to physically get 400 AH worth of battery in that battery compartment. If not, I will go with Lifelines or perhaps take the plunge into Bruce Schwab's Fireflys...let me know if you have any questions....

Jon

 

[jsalley]

Thanks Jon. I do have the OEM 4D's, and believe their capacity is still pretty good. The problem (I think) is the Raymarine radar scanner, which seems to be very sensitive to sudden voltage drops, even if brief and non sustained. I didn't have any problems with any of the other Raymarine gear (same as yours, I think) except the radar - and it only drops out with engine starts. I've heard of others with this issue as well, although it seems only to be a problem with Ray.

 

[Stu Jackson]

John, Maine Sail, who wrote one of the links I sent and many of the wiring diagrams in the first one, has often said that house banks should be able to start everything without electronics dropping out, and, if they do, he always suspects the wire sizing TO that particular "appliance." Many skippers go the Option 2 route first, though.

ITWMB, I'd carefully check the wiring AND connections to the the device that drops out before I redid my main wiring to Option 2 from what you have now. It could well be that the wiring to the device is fine, but perhaps small wires between the boat's system and the device are tiny - unfortunately, sometimes they are.

Good luck, either way.

 

[Maine Sail]

John,

Yes using the 27 as a dedicated start battery is fine and often the easiest way out of electronics drop outs. Sometimes it's the wiring & sometimes the battery bank.. You could also just hit STBY on the dome before hitting the starter...

 

[jsalley]

MS - Thanx. That's what I've been doing (putting scanner on standby during starts). I do a lot of sailing at night on the Chesapeake (lots of menhaden trawlers steering fast and erratic courses), and don't want to lose my radar if I need a panic engine start and forget to turn the scanner off. Will probably go the dedicated start bat route, since I'm reconfiguring my battery wiring anyway.

 

[Solstice]

Thanks Jon. I do have the OEM 4D's, and believe their capacity is still pretty good. The problem (I think) is the Raymarine radar scanner, which seems to be very sensitive to sudden voltage drops, even if brief and non sustained. I didn't have any problems with any of the other Raymarine gear (same as yours, I think) except the radar - and it only drops out with engine starts. I've heard of others with this issue as well, although it seems only to be a problem with Ray.

John,
After rereading your original post, I see you haven't paralleled the batteries yet? Are you having this problem when selecting 'Both'? If not, you may want to see how it works once the batteries are combined. It's easy enough to convert from Reserve to Start if that doesn't take care of it. Since our boats have a dedicated Start switch, I assume you are considering making the connection there? I also have the Ray radar, but have to admit, I only turn it on when needed and always on Standby initially.

 

[jsalley]

Jon - Yes, I was planning on coming off the engine on/off switch. I had also contemplated waiting until I parallel the 4D's; as you said, it would be easy to modify later, given the centralized location of the battery wiring on our boats. Thanks for weighing in!

 

[RIVERCRUISER]

Hi John,
I do have my system setup as Stu describes. As Stu says, no issue with using a dedicated Start, however I would be curious as to why your electronics are dropping out, or let me rephrase, why there is not enough battery capacity to create the situation.
Jon

It may not be a capacity problem.

In a different industry we experienced problems when installing new modern electronic components and powering them with old (1950's design) AC and DC electrical systems. The modern electronics would shut down when power sources were changed as in paralleling generators, etc. Our solution was to change our procedures to minimize power interruptions after the electronic units were powered up.

Not the best solution, but it was the most economical...