[C36IA] Loosefooted mains was Re:batteries
Bill Boggs
bill815 at hughes.net
Sat Jun 13 21:08:33 EDT 2009
What's the complaint with a loose footed main? I choose a loose foot main for my new sail after talking it over with my sailmaker. With a beefed up outhaul, it allows you much more control of the lower part of the main, its easier to bend on an off the boom and otherwise seems just as simple to deal with as footed sail. Seems to me the way to go for a performance oriented sailors
Bill Boggs
s/v Palmetto Moon
Stingray Point, VA
----- Original Message -----
From: Bob McCullough
To: gforaker at gmail.com ; Catalina 36 Association Mailing List
Sent: Saturday, June 13, 2009 10:06 AM
Subject: Re: [C36IA] golf cart batteries and Battery system design
Gene:
I'm in complete agreement with you. The 1-2-off switch is good protection for the batteries. The wiring harness update connected the alternator directly to the starting motor battery connection so all charging current would flow straight to the batteries via the 1-2-off switch. A simple good design. I did have a shore water inlet but with a shut off valve so no sink of the boat. I don't like mast furling mains either and I positively hate-loose footed mains. I did have a combiner so either the alternator or the battery charger would charge the batteries. My charger had leads for three banks but with the combiner I only had to use one lead for all three banks.
Maybe I should be the list curmudgeon. :-(
Bob M
----- Original Message -----
From: Gene Foraker
To: Catalina 36 Association Mailing List
Sent: Saturday, June 13, 2009 8:36 AM
Subject: Re: [C36IA] golf cart batteries and Battery system design
We HAVE been talking about the possibility and risk of a bad cell and it's implication on paralleled batteries. I have experience with a bad cell.
Steve - It is great that this has worked fine for the first 4 years. I'd be more concerned about the next 4 or 5 years. Bad cells do happen and you have no way of easily isolating it.
Jeff - The 1-2 -off switch allows you to isolate a bad battery. Hard wiring the alternator and charging system to paralleled batteries with no switch would allow the bad cell to soak up all of the charging current while still draining the good battery. You would still have the starting battery to start the engine, but would be unable to charge with the alternator because most of its output goes to the failing cell.
Please don't misunderstand me, I do advocate the benefits of on large paralleled banks, but only if they are monitored and only paralleled while you are on board.
I know, I am probably just a little too risk adverse on the boat:
I don't have a PSS seal because I don't want the risk of a bigger hole in the boat.
I don't have a shore water pressure hook up for the boat. Too many boats have sunk at the dock this way.
I don't have a mast furling main. I know yours hasn't jammed in the first 10 years, what about the second 10?
Boat systems don't usually fail when they are new, but when they are old. What happens with the inevitable failure?
Jeez, I'd better watch out or I will replace Miller as the list curmudgeon. ;-)
Gene
Jeff Cote wrote:
For what’s it worth I too am a systems design engineer (working in the marine systems industry) and have my house batteries in one large bank with a group 27 as dedicated starting battery. Having a larger battery bank does have its advantages:
<!--[if !supportLists]-->- <!--[endif]-->minimizes the depth of discharge which directly correlates to battery life (more battery cycles)
<!--[if !supportLists]-->- <!--[endif]-->ability to handle larger amp draw (e.g. inverter loads)
Notwithstanding there are some potential problems, such as a bad cell causing the whole battery bank to fail. As with everything on boats this decision is about trade-offs and in my opinion (due to low probability of a bad cell) the benefits of a larger single house bank outweigh the battery 1 and 2 approach.
As Steve mentions, the ideal situation is to have any battery bank composed of the same types and model, same age, and same location.
The 1-2-on-off battery switch design is riddled with unintended complications. Of which human error is the most common one. For instance:
<!--[if !supportLists]-->- <!--[endif]-->Forgetting to alternate batteries 1 and 2 regularly and consequently having either 1 or 2 handle most of the discharge cycles
<!--[if !supportLists]-->- <!--[endif]-->Leaving the switch on both and potentially deeply discharging all batteries without having a battery for engine start-up
A better approach is a dedicated house and engine battery. A switch in this instance is used only in case of emergency for back-up purposes. An automatic combiner relay (Blueseas ACR) can be used to have either battery charged when a charging voltage is present (e.g. alternator or battery charger). Furthermore one should also have the alternator connections bypassing the battery switch altogether and directly connected (with appropriate fuse of course) to the house bank. This eliminates the possibility of the battery switch disconnecting the alternator output current from the battery therefore frying the alternator.
The marine industry is pretty much in agreement on the depth of discharge rule: A balance between battery life (i.e. # of discharge cycles) and the depth of discharge is achieved at 50%.
Anyways… that my two cents.
Hope this helps.
Cheers,
JC
From: c36list-bounces at c36ia.com [mailto:c36list-bounces at c36ia.com] On Behalf Of Steve
Sent: Friday, June 12, 2009 7:15 PM
To: Catalina 36 Association Mailing List
Subject: Re: [C36IA] golf cart batteries
I'm an electrical engineer and I've had 4GC batteries hard wired in series/parallel for about 4 years now. I think it's the way to go. It reduces the depth of discharge to prolong the battery life. I understand the arguments against it but there are many very large battery banks that operate this way. The key is you can not mix batteries. You replace them all at the same time with all the same type. As with any issue there are pros and cons.
Granted, my area is most certainly not lead acid battery technology (I'm into digital hardware design and FPGAs - small wires!) but a large series/parallel bank (almost 500Ah) with a separate starting battery has worked very well for me and I would recommend it.
Steve
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From: Wait Griswold <wrgriswold at gmail.com>
To: Catalina 36 Association Mailing List <c36list at c36ia.com>
Sent: Friday, June 12, 2009 4:18:27 PM
Subject: Re: [C36IA] golf cart batteries
There used to be a guy on the list named Norm that argued long and persuasively against paralleling batteries just for that reason. He much preferred alternating days with each bank. I think he was an electrical engineer and was very knowledgeable.
Wait Griswold
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From: c36list-bounces at c36ia.com [mailto:c36list-bounces at c36ia.com] On Behalf Of Jeff
Sent: Friday, June 12, 2009 1:11 PM
To: 'Catalina 36 Association Mailing List'
Subject: Re: [C36IA] golf cart batteries
There's one problem any time your operate with the battery switch on "ALL", and this applies to both two and four battery configurations. If you have a bad or weak battery, it will draw down the good one(s). In essence, the good battery tries unsuccessfully to charge to bad one, and you can end up with all the batteries down.
Jeff
Con Brio
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From: c36list-bounces at c36ia.com [mailto:c36list-bounces at c36ia.com] On Behalf Of Wait Griswold
Sent: Friday, June 12, 2009 3:01 PM
To: 'Catalina 36 Association Mailing List'
Subject: Re: [C36IA] golf cart batteries
I think that in theory you will divide the load equally between the two banks. The batteries will not know if they are wired in parallel directly or through the switch. I say in theory because the batteries may not be exactly equal and I think that could influence the division of the load. In saying that I am getting lost in my mind and considering things that really don’t matter but are interesting to think about. That quirk of mine drives the Admiral crazy. If they are not equal, they will be close enough not to matter.
Remember that golf cart batteries are true deep cycle batteries and can be safely drawn further than marine deep cycle batteries that are not really deep cycle. I used to know the recommended safe level for GC batteries but now I am not sure. I think it was 50% or maybe lower (I seem to vaguely remember 20%); and that can be repeated hundreds of times.
Wait Griswold
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From: c36list-bounces at c36ia.com [mailto:c36list-bounces at c36ia.com] On Behalf Of Bill Hague
Sent: Friday, June 12, 2009 12:43 PM
To: Catalina 36 Association Mailing List
Subject: Re: [C36IA] golf cart batteries
Wait and Gene,
Our estimated use is 100amps/day. If I connected them in series, 2 to a bank, and chose "all "on the battery selection switch would I draw 50amps from each bank.I am trying to reduce the percentage of amps taken from each bank.. 50 amps from each bank would be about 20% of capacity from each bank. I don't want to take 100 amps ,40%, from one of the banks.
Bill
----- Original Message -----
From: Wait Griswold
To: 'Catalina 36 Association Mailing List'
Sent: Friday, June 12, 2009 3:15 PM
Subject: Re: [C36IA] golf cart batteries
Bill,
I would wire the new “12V” (actually 2 6 V) batteries just like the 4D’s through the existing switch. Then they can be paralleled just like the 4D’s or used individually if necessary, if for example one of the 6V batteries failed. In rereading your email, maybe that is what you meant.
Wait Griswold
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From: c36list-bounces at c36ia.com [mailto:c36list-bounces at c36ia.com] On Behalf Of Bill Hague
Sent: Friday, June 12, 2009 10:57 AM
To: c36list at c36ia.com
Subject: [C36IA] golf cart batteries
Thanks to Gene, Bob & Bill for the suggestions, and thank you to Gene and Mike for the photo's. I picked up the batteries this morning so I can now start measuring for the cables.
A few more questions:
1) Did you use 2/0 cables?
2)I had my 4d's connected in parallel to increase amp hour capacity. Is there any downside to doing this with the GC, after they are connected in series.My goal would be to reduce the percentage of amp hours removed in between charges?
Bill Miller,
I thought you were still using the 4D's?
Thanks
Bill
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