House Battery Power Wiring Picture
Michael T
Member Posts: 7,227 ✭✭✭✭✭
Last year I promised to post a picture to accompany a discussion we had about the proper way to wire house batteries - when you have more than one of them, to make them far stronger by functioning as if they were a single battery. The batteries in the picture are wired in the proper fashion. The battery to the far left in the picture is the Port engine starting battery so it has both the -ve and +ve cables attached to it. However, you will note that on the house battery bank - the battery to the farthest left has the main positive cable attached to it and the rest of the batteries' positives are "back wired" to it. The house battery to the farthest right has the negative cable attached to it and the rest of the batteries' negatives are "back wired" to it. This wiring scheme more than doubles the reserve minutes and amp hours of EACH battery thus creating a huge synergy. With this system when there is a draw on the battery bank the batteries act as one big battery. If wired differently they usually act as "stand alones" which means as the first one runs down it starts to draw from the second and so on, creating a scavenging effect. That creates a far faster draw down. Using the proper method is the cheapest way I can think of to get the most power from multiple house batteries. BIG BIG P.S .- I just noticed in the picture that the positive cable to the last battery is not connected, it's just lying there loose. This is the initial install and we were waiting for a new, shorter positive cable to arrive to simplify installation! It arrived and the job was completed. So I posted the Big Orange Filter picture again and you can barely see the "proper" finished battery bank install in the back ground with the new shorter cable LOL!!!.....too funny :-) P.P.S. FINALLY - Found a third picture (P5210651) with the finished set-up.
Comments
1 = port starter
2,3,4 = house battery bank, wired in parallel.
On the house bank, you have the house circuit connected between +ve2 and -ve4. Am I right?
@LaRea Yes, you are correct. The first battery is a Series 31 AGM that is the Port engine starter battery. It is wired as a single battery "stand alone" battery whose sole purpose is to start the Port engine.Ttherefore, it has a -ve cable to its -ve post and a +ve cable to its +ve post .....standard way to wire any single "stand alone" battery.
These three batteries (which you correctly refer to as batteries two, three and four) are Series 31 AGMs that comprise my house battery system.
What you correctly refer to as battery two, is the first of the house batteries.
This battery receives the hook-up of the main positive cable. The main +ve cable is attached to battery number two's +ve terminal. Then small positive cables have been run back to battery three and battery four.
What you correctly refer to as battery number four is the last of the (three) house batteries in the line.
For the hook-up of the main negative cable: The main -ve cable runs all the way down the battery bank to the -ve terminal on what you correctly refer to as battery number four. Then small -ve cables have been run back to battery three and then two.
The schematic I have shown makes all the batteries function as one. Their reserve minutes and amp hours are at LEAST doubled over what is often done - which is the main -ve and +ve cables are run to the first battery in a bank then connected via short cables to the remaining battery(ies). IF a bank is wired this way the load hits the first battery, starts to draw it down then the first battery starts to pull from the second, etc. This is called power scavenging and is a very inefficient method that has one battery trying to pump-up the next etc. which is very wasteful.
Regards MT
Go Steelers!!!
@Greg, Greg both the Starboard engine (and generator) and Port engine are on Series 31 AGMs. Each battery has 1000 marine cranking amps (MCA) which Mercury Technical Support (Fond du Lac Wisconsin) said was plenty for my 2014 Axius 8.2 Mags.
IF I was buying new batteries today I might get the new (as of late 2014) Thin Plate Pure Lead AGM Batteries. These are not much more expensive than the "regular" Series 31 AGMs. Their reserve minute and amp hour ratings are about the same but they have insane cranking power - 1370 MCA!.....HOWEVER they accept charge at 300% of their Ah which is the fastest charge rate of ANY type of battery and 3X faster than the very expensive lithium batteries. For now, I'm very happy with my 3 AGMs as we essentially treat them as shore power because we never even turn down the fridges while at anchor. When I replace them I will sure look at the new AGM technology.
In terms of raw voltage, you can connect to any terminal in the bank and you'll get exactly the same voltage. But you're saying that the battery system will perform better if you connect + to the first battery, and - to the last battery.
I believe this based on MT's say-so and some admittedly scant web research, although I don't understand it. I'd love to find a good explanation.
Thanks MT -- I'm planning to check my wiring!
@La Rea, Yes that's what I have been told.....and what seems to work extremely well for us. So well that we often forget that we're off shore power and one of us says Oh cr*p we had better turn a few things off/down LOL.
I can't take credit for this installation, although I believe I understand the concept. In fact I was told that the "regular" way that many batteries used to be hooked-up actually draws the power down faster as each battery is trying to "subsidize" the battery in front of it that is being drawn down. Does my explanation make sense? The process behind the picture of the installation I posted was told to me awhile ago by an electrical engineer.
However, before I purchased the AGMs, first for my 2013 Rinker EC 310 and then again for our 2014 EC 360 I decided to try to talk with some "experts". I was told to try the guys at Intellipower Battery Chargers and East Penn Deka Batteries. Both men I talked with said it was the ONLY way to wire the batteries. In fact, I believe Intellipower had a diagram to that effect - with an explanation on their website - including , I believe, the comment of how much the reserve and Ah were increased - which the guy at Penn Deka also said would happen.
As I mentioned they said, in effect, you turned the batteries into one huge battery. I'll see if I can find the posting. One thing for sure, those 3 AGMs of mine, wired in that manner, seem almost impossible (knock on wood) to draw down! BTW - as you can probably see from the pictures I left room to install a fourth AGM house battery "just in case" but we have found no need - so far - for the extra reserve capacity.
Just remembered..... one of the guys gave me an analogy to make sense of his explanation. He said that when a single battery starts to draw down it runs down faster and faster as it loses power, like a ball rolling down hill. But, when two or more batteries are properly linked they draw down much, much slower significantly delaying the rapid draw down phenomenon. That made a lot of sense to me.
is there a difference a big between the wiring diagram you posted and this one.