Vee-berth battery ventilation

May 16, 2015
42
C&C 37 128 Portland
Hey all,

As I prepare to mount a new windlass on my ‘85 C&C 37, I intend to install a new AGM 12v on the centerline just aft of the holding tank. There is plenty of room here for a battery platform and accessibility is fair. I’ve done my homework on voltage drop, cable size, etc. but if you have specific experience on a 37 with a fwd-mounted battery, I’m mostly ears.

My question relates to ventilation. The under-berth space is fairly large, but I know AGMs need to gas and I don’t want to create a hazard. Any suggestions for adding an adequate vent to this area?
 
Feb 21, 2013
3,794
Hunter 46 Point Richmond, CA
Cut slats OR drill 1 inch holes top and bottom under the berth vertical support.
 
Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
As I prepare to mount a new windlass on my ‘85 C&C 37, I intend to install a new AGM 12v on the centerline just aft of the holding tank.
Have you calculated the size of electrical wiring you will need if you don't install a forward battery near the windlass. This is not the best idea when you consider you can use ALL of your existing batteries plus the alternator for raising the anchor if you use fully sized lines to the windlass. With a small charging line only to the forward battery, that battery will supply most of the power and will see a major voltage drop when put to work. A far greater drop than a properly sized line would supply.

What really makes this really bad is that you are now stuck looking at venting the battery storage compartment. And you're going to need it as you'll be looking at significant charging (and gassing) after raising your anchor.
 
May 16, 2015
42
C&C 37 128 Portland
Ralph,
The battery would be charged from a 40A charger/80A alternator using AWG 4 conductor.

However! For about the same price as our new Lifeline 12v we could still go with 60' AWG 1. Partly for the reasons you mention, but also because I won't like the added weight in the bow, I'm tempted now to return the new battery (gp 27) and just use the house bank. This was my first plan, but my house bank consists of
  • 2 7-yr old agm 6v in series
parallel wired to
  • 1 1-yr old 12v agm
A far from ideal setup, I understand. PO started with the 6v Lifelines and tagged on another 12v for more amp hrs. I understand that the older/weaker AGMs will degrade the newer one. I will be replacing these, but for now the house bank stays at 13+ and seems to keep up with our light loads (sans fridge).

Will adding a windlass kill this bank?
 
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Oct 26, 2010
1,432
Hunter 40.5 Beaufort, SC
Will adding a windlass kill this bank?
It may but I wouldn't worry about "killing the 7 year old bank, at least if you're planning on keeping your boat for several more years. Your're looking at potentially replacing your 7 year old AGM's sometime in the next year or two anyway. But that's just my perspective.
 
Oct 22, 2014
16,145
CAL 35 Cruiser moored EVERETT WA
I went through the same education in battery management and install of a windlass 2 years ago.
An electric windlass will demand power to pull the load up from the bottom of the sea. Locating the batteries near the windlass adds weight to the bow but reduces the size of copper wire running through the boat from the engine/House Bank to the bow. Using the House Bank to power the windlass means you need to buy large cables to avoid voltage loss (which weigh a bit but the weight is distributed over the length of the boat).

A second consideration is usually you will be likely running the engine and charging the battery when you are trying to raise the anchor.

I chose the House Bank wire route to powering my windlass. The install took about a day to run the wires and secure everything.

As @smokey73 wisely points out 7 year old battery bank is like a 70 year old. If he/she has taken care to conserve health may still have a year left. If abused a bit, then you are likely going to be looking for replacements this season.
 
May 16, 2015
42
C&C 37 128 Portland
I'm going with the house bank plan, knowing I'll need to replace batteries this year. Thanks for drifting with me on the topic of battery ventilation:)
 
Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
As @smokey73 wisely points out 7 year old battery bank is like a 70 year old. If he/she has taken care to conserve health may still have a year left.

Hey, not very neighbourly :mad: .................. only a year left if well preserved. So you're saying with all those thousands of hours I've spent at the gym, I can only look forward to another year at best :doh: ? Great, something else to worry about in addition to the boat :eek: !

Will adding a windlass kill this bank?
I was thinking, will the bank kill the windlass ? As it was so rudely stated above, maybe the 7 Y.O. bank is good for another year but you're hoping for many years out of the windlass. If you're looking at 100'+ pulls as we often see up north of Vancouver, the windlass should be nice and toasty while hauling at 7-8 volts.

Just out of curiosity, how many watts does the windlass motor pull ?
 
Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
1 year in humans is like 10 years in battery years. :laugh:
The only comparison I can see between my remaining years and those of the old batteries is the unexpected off-gassing at the most inappropriate moments :sick: !

Off to the gym to see if I can add another 10 minutes to my remaining time.
 
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Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
Don't mean to piss on your cornflakes but you might want to check your windlass against your anchor rode.

I have a 15 kg. claw with a Lewmar VI windlass rated for 700W at normal loading. What the #$%@&* normal loading means with a Lewmar windlass is anyone's guess. Their specs could drive anyone over the brink and I used to size motors in process plants way back when. I can tell you that the Lewmar Vl is just right on the line for my rode.

I had a quick look at the specs for the Maxwell HRCFF-8. Every bit as bad as Lewmar for BS. Ignore the "WOW factor" maximum pull of 900 lbs. That is the locked rotor pull. Line speed at that point is "0". You have to find their "working load" and apply their factor of safety. Lewmar uses a safety factor of "4". No idea what Maxwell uses. I'm sure Maxwell is an ideal windlass for your application, you just have to know how to research their numbers.

1615935887816.png





600W is definitely on the small size unless the line speed is very low. This one is right up there at 108'/min. You've got lots of power back there if you're feeding right from the main batteries,so you might as well use it.
 
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Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
Just a sucker for punishment here. Had to look further into the Maxwell specs and found this:

1615947504950.png

If you have a basic understanding of power and electricity:

- The HRC 6 needs 600 watts to raise 200 lbs. at 81 ft/min.

- The HRC 8 can lift 300 lbs (50% heavier) at 108 ft/min. (33% faster) and yet still needs only the same 600 W.
- This is a 100.00% increase in work output of the windlass (according to their figures) and yet still requires only the same 600 W.

Right there, they're figures don't figure.

The most important number I was able to find in their literature is the factor of safety they require applied to their working load:

1615947858907.png



IMHO, I do not believe 600 W is sufficient power to handle their quoted 300# working load divided by a safety factor of 3 which comes out in the wash at 100 lbs.

Actually, glad I read their installation manual. Now I appreciate that Lewmar isn't the only BS artist out there when it comes to pushing windlasses.
 

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May 16, 2015
42
C&C 37 128 Portland
Just a word of thanks for talking me out of mounting windlass dedicated battery forward. Happy about not having all that added weight up there. Routed 1/0 aft to house AGMs in lazarette with the breaker accessible there, too. Installed foot switches on deck but opted out of the cockpit remote, going with wireless controls instead.
 
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