Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 08-09-2006, 18:47   #1
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
why have a starter bank

given that im going to be installing 2 9.9 yamahas explain to me why i would bother having a seperate starting battery and not just put extra battery capacity into the house banks, i realise that if there is not enough power left in the houes bank i cannot start the motor however i have hand started one of these before and they are not that hard to pull over so what reason would i have to have a whole other battery just for starting ?? if i just had one bank then i could use my outboards for charging the house bank as well as the solar panels as well as elimate a bit of wiring, as for hand starting the things i planned to cut a hole in the side of my seat and put a screw out access hatch there so i could pull the motor over from the side, so are there any reasons why i really need a seperate starting battery
sean
__________________

__________________
northerncat is offline   Reply With Quote
Old 08-09-2006, 20:00   #2
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2006
Location: Chesapeake Region and Maine
Boat: 42' Bob Perry sloop
Posts: 4,038
Images: 4
Two possible reasons: redundancy and convenience. Redundancy in the event your house batteries go flat, and convenience so you don't have to cut a hole or bother with hand-starting.

Re: extra wiring, yeah, there'd be a bit. You could still rig your Yamaha's to charge the house batteries, though, and use a little device like an EchoCharger to keep the starting battery topped off. Easy, relatively cheap, effective.

But, you've gotta decide whether or not it's worth it.

Bill
__________________

__________________
btrayfors is offline   Reply With Quote
Old 08-09-2006, 23:09   #3
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
The main reason for a "house" bank and a "start" bank is that the two types of battery are very different from each other. A house bank is or should be a Deep cycle battery. Deep cycle is very poor at supplying the laod requirements of a starter motor or anchor winch. A "start" battery is very poor at suppling the demands of long term low energy drains.
However, in your situation, the demand of starting a 9.9 outboard is so low that a deep cycle "house" battery would do it with ease.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 08-09-2006, 23:44   #4
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Question 2 U

Is there any reason why you're not running (1) 25 hp OB instead of two 9.9's?
__________________
delmarrey is offline   Reply With Quote
Old 09-09-2006, 00:01   #5
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
my house bank will be 400ahrs which i would think would be plenty for starting 2 9.9s which dont require a lot of current to start any way, delmarryey the 9.9s push my boat along at 10+ knots so i cant see the reason to go for the 25's which will just use more petrol for a small increase in top speed
sean
__________________
northerncat is offline   Reply With Quote
Old 09-09-2006, 01:20   #6
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
Sean, what delmarrey was meaning was why two 9.9's as against ONE 25hp.
I would love to know more about your boat. What is it, weight, length, hull shape etc. Reason why is that I ahve just been talking to a friend about putting outboards on the back of his boat. He has a VERY old VERY heavey Ford diesel that is probably about 90Hp. The boat has a planing hull, but they don't plane it, they may push it to 11knts tops. The time is soon aproaching that the engien and old leg may have to go, so I have suggest why not look at twom small outboards on the back. They are going to loose 500Kg odd in old engine and leg and I reckon this boat will require very little to push it along. She is 36ft and 6500Kg. I reckon two 25's or 40's would be more than adiquate. So how does your boat perform?
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 09-09-2006, 02:02   #7
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
What I'm suggesting

is since you have two motors, why not two batteries. One smaller for each motor. With a 1-2 switch to your main pannel. I'm assuming this is a power boat. The charging system on those smaller motors are not the greatest for depenability (around 6 amp). And if your using a bunch of electronics, two batteries would help reduce the load on the charging systems. a 400 ah battery can put a real strain on a small O/B if it happens to run down e.i. At anchor.

Where as, a 25 hp motor has a more dependable charging system. and can EZ'ly keep up with a higher load like; radar, VHF, lights, and starts plus what ever other toys a man/woman may have on the boat.

If your running an inverter your 400 ah will be fine but you wouldn't want to drain it down very far......................._/)
__________________
delmarrey is offline   Reply With Quote
Old 09-09-2006, 02:25   #8
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
it is a sailing cat with the 9.9s as auxilarys, im looking at cutting weight and have started to ponder the necessity of a starting battery as it would seem to be extra hassle i.e extra weight,wiring and if i just go with one bank i can have my outboards charging it and save a few dollars as well
as for the boat it is under construction but you can check a few photos of it here check out sean and tania cairns http://easycat.50webs.com/easy_cruising_general_005.htm
__________________
northerncat is offline   Reply With Quote
Old 09-09-2006, 06:05   #9
Registered User
 
Sunspot Baby's Avatar

Join Date: May 2003
Location: New Bern, NC
Boat: Prout Manta 38' Catamaran - Sunspot Baby
Posts: 1,521
Images: 14
Another reasons catamarans have dedicated starting batteries is to avoid the long cable runs and associated voltage drop. With the battery close to the engine, a wire run from the switch to the solenoid is much lighter. I have a 30A relay so assure the solenoid gets full voltage.

Since your running 9.9 outboards that are, as you say, easy to pull, maybe you want to save the weight. Another consideration would be a motor cycle battery as a dedicated start battery at each engine. Much lighter and you still have the redundancy and convenience.

Seems you are really making good progress on construction. Good on you mate!

George
__________________
She took my address and my name
Put my credit to shame
Sunspot Baby, sure had a real good time
Bob Seger
Sunspot Baby is offline   Reply With Quote
Old 09-09-2006, 08:51   #10
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,055
Sean-
A couple of reasons that you can weigh. As others have said, reliability. You preserve the starting battery isolated, and that ensures you'll have one if there is *any* type of battery, cable, or systems failure in the main bank. Let's say the wind is slack and the USS Ronald Reagan is coming down at you doing 40 knots and you'd like to motor out of the way NOW. Nice to know the starting battery is going to be reliable.

Bear in mind that a dedicated starting battery can be a WEE THING and that also makes it a cheap thing, which won't hurt to replace as needed. And by locating it near the engine, you can use smaller cabling for it, another convenience and cost cutter. Or one starter battery cabled out to both of your engines, located between them or directly AT one.

I can't see that a 9.9 would take a heavy starting current, and most deep cycles can provide a strong enough surge to start larger engines with no damage to them, but I would also check the starter motor draw, against the current rating for whatever battery you plan to start them with. It shouldn't be a problem, but it is easier to check.

What's the worst thing that can happen with only one battery bank? You become a sailboat, you need patience, and the USS Ronald Reagan chalks up another silhouette on her island.<G>
__________________
hellosailor is offline   Reply With Quote
Old 09-09-2006, 16:59   #11
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
my main house bank is only going to be about 2m from one motor and 4m from the other
sean
__________________
northerncat is offline   Reply With Quote
Old 09-09-2006, 17:43   #12
Registered User
 
Jon D's Avatar

Join Date: Sep 2004
Location: Ft. Lauderdale, FL currently CLODs [cruisers living on dirt]
Posts: 423
Images: 11
Sean

FWIW and IMHO with 9.9 outboards I would not add the complexity.

Dedicated starting batteries become real important when you can't pull/crank start you main engine. Then you don't want to be caught without a way to start it if you can avoid it.
__________________
Jon
S/Y Sirius
Moody 47
Jon D is offline   Reply With Quote
Old 09-09-2006, 23:30   #13
Registered User

Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
Images: 41
by complexity do you mean having a starting battery or noit having one and having to start the motors with the house bank
__________________
northerncat is offline   Reply With Quote
Old 10-09-2006, 16:08   #14
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,055
BTW, do these 9.9's have pull-starts on them?
__________________
hellosailor is offline   Reply With Quote
Old 10-09-2006, 16:12   #15
Registered User
 
Jon D's Avatar

Join Date: Sep 2004
Location: Ft. Lauderdale, FL currently CLODs [cruisers living on dirt]
Posts: 423
Images: 11
Quote:
Originally Posted by northerncat
by complexity do you mean having a starting battery or noit having one and having to start the motors with the house bank
I meant just start them with the house bank. They don't need enough juice to worry about and you can always pull start them.
__________________

__________________
Jon
S/Y Sirius
Moody 47
Jon D is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric Main Drive(s) Limpet Multihull Sailboats 551 08-01-2012 08:37
Which engine? Moby Dick Engines and Propulsion Systems 34 03-08-2006 07:32
Two Banks used as one. Charlie Electrical: Batteries, Generators & Solar 22 02-08-2006 15:54
Seeking Advice on Common Configurations ssullivan Electrical: Batteries, Generators & Solar 54 09-05-2006 07:38



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 00:54.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.