Battery Idea: 1 big house bank, no starter

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cqr35	Battery Idea: 1 big house bank, no starter		Lead	[-]
Posts: 8 01/15/08 14:15:28	Tags : None I need to replace my 4D lead acid batts and am wondering if this idea is crazy: I am considering 3 new gels or AGMs (2 in port cabin, one at bulkhead) and wiring them all in parralell as one big house bank. That would presumably reduce the degree of discharge on them, and give me lots of Ah's. As a precaution, I would carry one of those battery jump starters in case I ran the house bank too low to start the engine. I always run it when using the windlass, and it seems like a huge waste of space to dedicate a 4D to start a 56 hp diesel. In addition, I always forget to switch the perko to start, start, then switch back to house, so I use house most of the time anyway! Thoughts? Kevin Harmony #729
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yorkrose		#1	[url]	[-]
Posts: 250 01/15/08 14:45:29	Kevin, There is a never-ending religious war regarding connecting large house banks in parallel or using smaller banks serially. Personally, I like the large bank idea. However, in this case the physical location of the batteries makes such a parallel connection a poor idea. The long wire between the third battery up front and the two in the back should not really be used as the parallel connection. There could be voltage drops that would give you less performance than you might expect, due to the imbalance among the three batteries. The hook-up would probably also violate the ABYC guidelines for electrical connections. In general, such permanent connections should be kept shorter than a few feet unless additional fuses are installed. The forward 4D also operates the anchor windlass. That is one of the primary reasons the third battery is located nearer the front of the boat. Finally, make sure you really understand how your system is currently wired. The scheme seems to change from time to time. On our boat the wiring from the factory was not as shown in the owner's manual. It is OK; just not as drawn. Regards, Gene Fuller Yorkshire Rose, C42 #870
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rbetzing		#2	[url]	[-]
Posts: 58 01/15/08 16:12:55	That is the way I have my house bank set up. All 3 4Ds are connected to battery switch 1 as the house bank and then I installed a seperate Group27 battery connected to switch position 2 as the start battery. Ron Desperado 2000 C42/2 cabin #708 San Diego, CA
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lakandjc		#3	[url]	[-]
Posts: 143 01/15/08 17:57:04	FWIW I used the forward batteries as part of the house batts in the garage and had a small AGM starting batt tucked in a corner. This worked very well in 2.5 years of cruising in Mexico with no charging or usage problems. We used golfcarts to keep the cost down. But if you wanted to use non-wet batts, I stongly urge AGMs instead of gels. AGMs charge better and present less problems. I used AGMs on my previous boat and they gave trouble free service for many years. James Collins
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pdrimmer		#4	[url]	[-]
Posts: 150 01/16/08 06:16:26	I changed to AGM's. When I added a new alternator and regulator I wired the alternator to the batteries through a battery isolator and added another selector switch for the starting battery. These connections do not go through the battery switch so you do not have to remember what switch position you are in. A small starting battery and echo charger complete a foolproof and very reliable installation. I only use the selector switch on the load side, it is reminder that we have to charge the batteries. I also have the ability to use all of the batteries to start the engine, but I have never needed to do that. Finally, while I used 4D's alot of people have used AGM golf cart batteries with goood success.
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Bob VonDrachek		#5	[url]	[-]
Posts: 21 01/16/08 08:13:19	Is there any difference between wiring the 3 batteries in parrallel and just leaving the selector switch in the "both" position?
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CaptNorm42	Parallel Batteries	#6	[url]	[-]
Posts: 616 01/16/08 10:07:18 Moderator	Kevin, Gene is right, there is much debate on putting batteries in parallel. I also agree, the long run to the forward battery is less than ideal. My personal feeling is I DO NOT recommend everything in parallel. If you put 3 @ 12-volt batteries in parallel, you have 18 cells. If one of them shorts out (my feeling is in a bouncing boat there definitely is that possibility), that battery will produce roughly 10-volts. The other 2 healthy 12-volt batteries will try to charge the dead battery, causing havock in the bank, possibily making the entire bank unusable. I still feel if you just keep the original configuration (3 batteries/banks), the way Catalina wired them is the best. One battery pretty much dedicated to be sure the diesel will start, 2 batteries as a house bank. But, my personal feeling is adding a dedicated starting battery is by far the best. The link below has more info about my favorite small Optima battery and how it is wired with a second 2-bank Perko switch along with a crude photo. In all fairness, if you have a Freedom inverter/charger, you don't have much of a choice. I haven't researched it recently, but, in the past (and I think still now) this charger only only has one 12-volt input/output. The way it was designed is to have all house batteries in parallel. I really like my factory configuration of a 3-bank battery charger (charges them independently) and a seperate inverter. The inverter gets its juice from the battery(s) selected from the Perko switches. Besides, this charger works perfectly with my Honda 1000. http://catalina42discussionforum.yuku.com/topic/915 ~~~~_/)~~~~ Norm Perron, Hull #600/2 cabin, Aphrodisiac, Marina del Rey, CA Last Edited By: CaptNorm42 01/16/08 10:09:57. Edited 1 time.
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svzephyr44		#7	[url]	[-]
Posts: 113 01/24/08 16:22:13	OK - My question. At the moment my battery wiring is the two aft batteries are each "Bat 1" and "Bat 2" and the foward battery is in parallel with "bat2" Are you suggesting I would be better off it I paralleled the aft two batteries as "Bat 1" and the forward battery as "Bat 2" Of course this way the anchor windless would only be running off a single battery, but since I always run the engine when using the windless I don't know how big a problem this would be. The down side is that the forward battery would become my "starting battery" but would never be completely isolated from the boat as it would always be attached to the windless. Roger REBOOT USA 60493
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CaptNorm42		#8	[url]	[-]
Posts: 616 01/27/08 08:00:00 Moderator	I think both aft batteries are in parallel from the factory. So that makes the forward battery the starting battery. Considering the heavy circuit breaker for the windlass, you can assume it will stay off except when you turn it on. There is nothing else to discharge it, so it would be an OK starting battery. As was mentioned, the windlass is only used then the engine is on, so that is no problem. The only drawback to the forward one as the starting battery is the long cable run will give you a bit more of a voltage drop when the starter is on. Catalina actually did a great job there of putting double-ought (00 gauge) cable, to reduce the voltage drop with all battery cables. If you really want my opinion, it would be to put another 2-bank Perko (just like the factory switch) switch in the circuit. This way, you could select which battery to start from. Then you may be tempted in getting a real starting battery as you could connect it to this new switch. I've mentioned it before, but will repeat I installed an Optima 1000 near the other 2 aft batteries. It has worked flawlessly for 10.5 years, no maintenance. It is also shares compatible charging characteristics as 4D's. ~~~~_/)~~~~ Norm Perron, Hull #600/2 cabin, Aphrodisiac, Marina del Rey, CA
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Battery Idea: 1 big house bank, no starter

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