House Batteries - Question

Michael T

Hey Guys, Opinions appreciated! I am getting ready to install the batteries in my 2014 EC 360. Comments from anyone, particularly from those familiar with 342/350/360 Rinkers would be appreciated. All batteries will be series 31 AGM. One battery will be installed in the starboard engine bay for the starboard engine and the generator. I plan to install 4 batteries in the port engine bay. One for the port engine and 3 for the house batteries. The house batteries will be wired properly to enhance charging and reduce draw ( that is the main positive lead to the +ve terminal of the first battery and the main negative lead to the -ve terminal of the last battery) for parallel hook-up that maintains (in fact enhances) the 12 volt load capability. I can't decide if I want to have 4 house batteries but that would be an extra 70 pounds of weight to starboard and probably overkill? Of course everyone uses their boats somewhat differently regarding time spent at the dock v.s. at anchor - BUT I would like to know how many house batteries owners/users of 342/350/360 Rinkers have installed and any comments. Thanks! :-) MT

Black_Diamond

I have 2 house batteries on my 342 and they cover me just fine when on the hook or long trips. That includes that I have had genny issues since day one.....but I digress.

LaRea

Two group 31 house batteries.  It has always worked fine for me, as long as I replace them regularly, and run the generator a few times during the day.  Three would be a nice luxury. Four sounds like overkill, i.e. too much weight penalty.

craigswardmtb

I have two group 31s for house and two group 27s all on the starboard side. On my 360 the genny is on the port and I think it balances it out just fine. Minimal listing unless I have full water.

Michael T

Gentlemen, thank you for the great information and for the speedy replies! I'll go with 3 series 31 AGM House batteries. I agree that 4 would be overkill and a weight penalty. P.S. I have looked at a number of boats while contemplating this issue and you would not believe how many have their house batteries wired to give less power than they should provide by not taking advantage of the electrical synergy of a "unified" bank of batteries. In fact on one battery website (I think it might be Penn Deka) they state you can double the Ah capability of your batteries by wiring them in parallel - properly. :-) MT

MarkB

Micheal, why aren't you considering distributing the weight more evenly between port and starboard. If you like to keep your water tank full and waste empty, you will likely have a list if you have 4 batteries on port side. You can avoid this by going 2 on one side and 3 on other side where waste tank is.

Dream_Inn

well, if it means anything, I've had two 31 house batteries for 2 seasons now with my 400 with no issues whatsoever.  I think a third is overkill unless you tend to run a lot of DC stuff while on the hook.  I do not run my genny a bunch, typically twice a day for an hour or two each time.  I think the key for me is keeping the fridges at the half way point while on battery, and turning up while on shore or genny power.

Michael T

Hey guys, thankyou - your thoughtful comments are most appreciated! :-)  Mark on my 360 the generator, hot water heater, drinking water tank (which we keep full)  and one battery are already on the starboard side, so that is quite a bit of weight. I also plan to put any heavy items that I can on the starboard side of the storage areas above and below. I hope that this will balance the weight of the head and galley and galley storage cupboards which are to port. My thinking was that the weight of the two starting batteries would cancel each other out balance wise. That would leave 3 house batteries at 70 pounds each or 210 pounds "extra" - to port. I have a friend (who is often on this talk list) with an EC 340 that has one battery to starboard and 4 to port and another acquaintence at the same marina as him who has a 350 with the same configuration. Soooo - I hope that I will be able to balance things out. Also, I don't think there's enough room on the starboard side of the engine bay to put two batteries and even if there was it would be quite the cable run. DI, on my 310 last year I had two 31 AGMs for house batteries and never turned either of the fridges down and ran LED underwater lights and other items at the same time without problem. But now, the galley fridge for the 360 is twice the size of the one on the 310 and there are a lot more lights in the 360 - including 4 red/blue/white combination lights in the hard top - soooo - I was looking for a bit more "firepower". What I might do is put the boat in the water with two starting and two house batteries then lay the third house battery in the port bay to see if the boat flips! :-) Once again, thanks everyone!!!!! :-) MT  .....P.S. I took a picture of my friend's 340 (which has the port engine removed for a drive repair) - $$$$$.  It shows his port battery bank with the starting battery and three house batteries.

Michael T

Hhey Steve, my friend does keep a clean bilge. The boat is starting its fourth season. Those are merc 5.7s. Diesel that colour- farm diesel? MT

Hamdog

I have two Group 27's as starter batteries and 2 Group 31's as House Batteries. Upcoming season will be our 5th and no problems at all. We typically stay on the hook 2 nights per stay and 3 weekends out of the month. Has not been an issue.

OldDogNewTrix

Hey Michael, thanks for the photo. I forgot to take some when I was polishing last weekend. If you took any others, could you email them to me please? I'm thinking of going AGM next time around, possibly at some point this season. Where have you found the best prices for the group 31's? As I mentioned to you, I had a few early morning alarms last summer when the batteries dipped too low. We usually run a fan or 2 overnight as well as the 2 fridges. I'm also thinking that some days we never go over 1500 rpm's when travelling through all the locks and possibly the charger doesn't do its job properly. Anyone have any thoughts on that theory? Wayne

kneedeep

ODNT, what happened?? Why is your engine out? Marcus

Michael T

Wayne, one of the main reasons I have bought AGMs for two boats now is that they accept a charge 40% faster than the most battery types. Of course the significance of this is threefold: first you don't have to run your engines as fast for as long a time. Second you don't have to use your generator as often or as long a period and third they charge much faster and discharge slower, I will definately send you all of the pics I took of your boat. BTW - There is a new AGM battery on the market. I think it is called a thin plate full lead AGM. It is a premium battery with a super premium price but it allegedly accepts a charge 300% easier/faster than any other type. But, for me that technology is too new and too pricey. Also a big part of house battery performance is how they are wired trogether. At least 50% of the house wirings I have seen are not done for maximum performance. I'm not saying they are done in a way that is harmful but the way they are wired will deprive the boat owner of about 25% of the house bank's total capable power. :-) MT

Michael T

Well Steve, even though series 31 AGMs (or 4D/8D AGMs) are beasts they do (of course)  have to be re-charged. Because they accept a charge much, much better (as in faster and deeper) that deep-cycle flooded  you can usually re-charge them at low displacement speeds, like under 1500 rpm. As well, if you have to use your generator to charge them you save time, money and noise because they charge so much faster. A lot of the guys I meet at marinas and even the techs who were showing us the operation of our EC 310 last year said to turn the fridges down to half when cruising. We never had to with the AGMs and we could blast tunes etc. while on the hook. Once the boat was underway again even at very slow speeds they charged right up real fast. I'd like to take credit for the decision to buy AGMs but it was a conversation with an electrical engineer who was  installing a solar "farm" in town who sold me on them for cruising. BTW the next generation of AGMs is out and they will accept a charge 300% faster that DCFs and they are apparently REAL hard to run down - but - way too steep $$$$ for my pockets. Rinker has all my money! Maybe Randy will have them in his cruiser? :-) MT

craigswardmtb

In my line of business we use 12v lithium iron phosphate or lithium nano batteries. It puts any sla, nimh, lithium ion battery to shame. When compared to typical flooded cell sla batteries they are 1/3 the weight, get 5x the cycle life, do not suffer from deep discharge, recharge 3x faster, are sealed and generally more tolerant to adverse conditions. They are also about 700% more expensive. I have about 20 of ese batteries sitting around. I really need to figure out if they would work as a house battery. As for AGMs, check out the deka/Duracell AGMs at SAMs Club. The cheapest I could find.

Michael T

Craig, if you could work a marine application for your LIPs you'd be a very rich man. The weight saving alone would be a huge factor not to mention all of the other +ve attributes.There's no doubt in my mind that something like that is coming. Yes, I hear that Sam's Club has an amazing price on the AGMs. I got a pretty good deal from my marina when I bought the 360. I wrote into the sales agreement that they would provide 5 AGM batteries at their cost which is really good. But, as your great advice suggests - go to Sam's Club for your aftermarket AGMs!  MT

craigswardmtb

I hear ya MT. These batteries really revolutionized my industry about 3 years ago. We manufacture wireless mobile computing and medication EMR carts in healthcare. Nurses are using these mission critical devices 24/7 and they rely on uptime and not being plugged in. These batteries cured all the woes of sla. Most other verticals the added cost is a tough sell. Right now I have 20k of these taking up space in my storage unit.

Michael T

Craig, I know from firsthand experience how your batteries have helped health care. I get a transfusion once a month and it is regulated by a portable infusion computer. It has really helped the nurses out and made transfusions safer and the locations for them flexible.Those batteries were a game changer for medical devices. :-) MT

OldDogNewTrix

KneeDeep, my port drive developed quite a bit of play resulting in awful tracking, especially at low speeds. The straight ahead feature of the Axius / Vesselview would always be off 10 degrees but I could at least re compensate for it. Without that feature, the boat wandered all over the place. I just heard the right parts finally came in and it's all being put back together today. Thankfully, I had the extended warranty! Michael, thanks for the photos and explanation on the AGM batteries. From the research I've done, it looks like starting and deep cycle are all in one with the AGM's? I'm estimating about $300 x 5 = $1500 for a direct replacement of my present set up. Are mine wired as you suggest?

Michael T

Wayne, it doesn't look like it to me. I'll tell you what I was told and why. Sooo the +ve cable from your battery charger should go to the +ve termimal of the first battery. Then the +ve leads from battery one to two and two to three are connected as usual. HOWEVER the -ve cable from the battery charger should be run to the -ve terminal of the LAST battery (in your case #3). That will probably mean that you will either need to install a longer -ve cable from your battery charger or connect two cables together to get enough length (this is okay). Sooo now you have the -ve cable from your battery charger attached to the -ve terminal of your LAST battery. Next the -ve cable from three to two and two to one are connected as usual (short connecting cables). REASON: when the batteries are connected in parallel in THIS manner all of the batteries share the load SIMULTANEOUSLY which makes them Far stronger and WAY more resistant to draw down because they are working as a team. IF - as is often or maybe usually the case - the +ve cable from the battery charger is connected to the + terminal of the first battery and the -ve cable from the battery charger is connected to the -ve terminal of the first battery and the rest were hooked up from them - when electrical load is applied it would hit the first battery and draw it down before hitting the second battery and drawing it down, then finally hitting the thirtd battery and drawing it down. In effect the batteries would NOT be acting as a unified "team"  but almost as stand alone batteries. They would still be connected as a battery bank but not nearly as effective a bank as they could be.They would draw down faster and charge slower. AS WELL, it has been reported that the way I was told to connect them can double the effective Amp Hours (a very big deal) of your battery bank. As you know I used two Series 31 105 Ah AGMs last year and I could not knock them down. This year I will use 3 Series 31 105 AH AGM batteries. If I was not clear please feel free to tell me and I'll take another whack at the explanation -or -  telephone me. I would like to take credit for this information but it was imparted unto me by an electrical engineer who is way smarter on these matters than I. :-) MT

OldDogNewTrix

Michael, thanks for this explanation, makes sense. However, wouldn't your way actually be in series, meaning that it would be sending out 36 volts? If i,m wrong, then it will be easy to switch them around . The charger is on the firewall beside/ behind the waste tank. So both the +ve and the -ve cables are going to the furthest away battery. I'll just bring one of them up to the closer battery. If that is the proper way to do it.

Cableguy Greg

All three batteries are in parallel. The difference is that the positive wire on battery #1 is connected to the positive that feeds the boat. The negative of battery three is connected to the negative that feeds the boat. The three battery positives are connected to each other. The three battery negatives are connected to each other. Traditionally the negative is connected to battery #1. MT is saying connect that negative to battery #3. What he is saying makes sense to me.

When a bank is in series, the negative of battery #1 is connected to the positive of battery #2, then the negative of #2 is connected to the positive of #3, giving you 36VDC.

Michael T

!00% Greg. MT.....BTW I just remembered something else the engineer said. He said that most batteries, regardless of their chemistry - (although AGMs and Gels are better) - resist discharge quite well until they get to a dischsrge of -Ii think he said - 25 to 30%. From that point on the rate of disicharge speeds up until you get to the 10.5 volt danger range. Therefore, anything that you can do to assist your battery bank discharge and recharge evenly and as a synergistic unit is to be strived for. OK that's it, I'm done :-) MT

OldDogNewTrix

Ahhh, got it. I'll be re arranging the cables as soon as the boat gets launched! Thanks for clearing up my confusion Greg and Michael.

Michael T

Wayne, in Canada the best place I have found was through our marina. You purchased your boat there, have a slip there, winterize and store it there as well as giving them all of your service. I'd talk with Wendy and Bonnie M. I bet they'd give you a discount that paired with their dealer price would beat the heck out of anything you could buy retail. Worth a shot - yes? MT

Dream_Inn

MT, I'm not sure I can completely buy into the parallel connection thing. I'm not saying it's better, cause it definitely is. But to me, the reason it's a better way to connect is because a lot of people don't use the correct wire gauge to connect the batteries and also because people also don't keep the terminals clean. Now, before I go further, yes, I do have mine connected the way you say. If you really think of the basics, using a low resistance wire and minimal length should give you no voltage drop across the connections. Again, I'm not arguing with you, it should be connected the way you state, but I believe for other reasons than stated.

Michael T

DI, I should have explained it better. I can get too wordy. The theory, which I am in agreement with 100%, is that the less effective way to wire the house batteries leaves the first battery to take the initial load, it then starts to draw from the second and the second will then draw from the third. This becomes a sort of catch-up situation. This creates what I'd term a "differentiated draw down" with all 3 batteries at different rates of a discharged state - not effective voltage management.That is how batteries in "stacked parallel" or "back wired" from the first battery situation perform. They discharge faster and recharge slower. They arrive at their rapid discharge tipping point faster - and worse yet at different times. By putting the main +ve cable on the +ve terminal of the first battery in the bank and the main -ve cable on the negatvie terminal of the last battery in the bank - the batteries, according to the electrical physics of batteries, will receive the load or draw simultaneously. I have read in a number of respected sources that claim this can double the amp hours of your battery bank. Of course, I am assuming that people use the correct gauge of wire. It is so easy to calculate the correct gauge or look it up on any of a number of readily available tables that I expect that to be the case. I am trying to scan a file to the forum. If I can I will. I'll also try to scan a diagram. :-) MT

frenchship

Hi Is this what you are talking about. Thanks Paul

MarkB

So what if you have 2 batteries. Is it better to hook up on series, ie 24', or the way you are saying Micheal with + to +, - to -, and tie into the circuit via one wire from each battery.

Dream_Inn

Mark, that really is a completely different question. Here, we are talking only parallel connections, either way it is connected. For your question, you would not want series, giving 24Vdc. You would want a parallel connection as well. If there was absolutely no resistance in the connections, it would not matter which way they are parallel connected. But since there is, in the second picture shown, the last battery furthest away from the charger connection would have the highest resistance thus discharging or recharging last.

Michael T

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