battery & wiring questions

daydreams · Post by **daydreams** » Feb 4th, '09, 16:48

Hi guys,
I want to build battery boxes and install new cables. What should I use?
I have always used the 24 group battery.
1 battery for the port and 2 for the sb on a [1-2 or both battery switch]. one of the 2 would also handle the electronics.
Is #1 cable ok?

Should the VHF, Radar, AM/FM, GPS, etc come off of the battery directly
or a fuse strip in the bilge [forward bulkhead] electric box fed from a #2 cable from the battery switch? or the battery directly?
or a fuse strip in the bridge.
Thanks in advance Gary

Capn' Tony · Post by **Capn' Tony** » Feb 4th, '09, 17:28

Gary,
What I have set up are 2 batteries (8D's) one for each engine. I added a heavy duty battery with an on off switch on the bridge cabled back to my starb engine Alt. I added a fuse bolck and run all my electronics of it. What I need to add is an inline sensor (forget what its called) to control what battery needs charging. Has worked for me for several years.

CaptPatrick · Post by **CaptPatrick** » Feb 4th, '09, 17:48

Gary,

I'd keep the cranking batteries separate from the house/electronics battery. Wire your cranking batteries on the main battery switch, (on/off. 1, 2 , both), and just an on/ff battery switch for the house. If you wire electronics to a cranking battery you could damage something electronic, you'll lose powere to the electronics if they are on and you crank the engine, and you can get noise from the engines that will give you interference problems.

On the cranking batteries, wire in a parallel circuit using a starter solenoid or relay. If one of the cranking batteries is too low to crank the engine, just push a momentary spst switch on the bridge to instantly parallel both.

Cable size is dependant on amp load & wire length, A standard chart can be seen here: http://www.alternatorparts.com/wire_size_chart.htm

The only things connected directly to the batteries should be the main cables, isolator, and charger leads. Every thing else should come from a DC electrical panel or at least a terminal strip or fuse block, supplied after the battery switches. Bilge pumps should be connected before the battery switch(s) so that there is no way that they be accidentally shut off. Unnecessary wires going directly to the battery should be avoided.

Spread the bilge pump hook ups between the batteries, only one pump per battery...

Br,

Patrick

daydreams · Post by **daydreams** » Feb 4th, '09, 19:14

It always sounds so simple when you know what your doing.
Thanks

Ed Curry · Post by **Ed Curry** » Feb 4th, '09, 19:40

I have two group 24 batteries for cranking and an 8d on a shelf in the bilge between the engines for the house bank. I run a combiner for the two starting batteries off one alternator and the house bank off the other. I went way oversize on the wiring for the house bank as it is in an engine space.

JohnD · Post by **JohnD** » Feb 4th, '09, 22:25

Gary, this is good advise, as always.

I have to say the bigest shock of my repower was adding up the cost of parts for wiring batteries to turn my CAT's. In total I think it was over $2k, keeping in mind I had some long runs to the starters.

I envy the simplicty of the B31 wiring.....

br,
JohnD

IRGuy · Post by **IRGuy** » Feb 4th, '09, 23:10

Daydreams...

Send me an email so I can have your address and I will send you a writeup I just finished on what I just installed in my boat. New batteries, made new boxes, new panel, and a complete rewire of everything in the engine room. I have not yet installed a splitter but everything else is documented.

"IRGuy@aol.com"

Bruce · Post by **Bruce** » Feb 5th, '09, 07:12

At all costs try and prevent the use of isolators and use battery switches to combine charging requirements.

The voltage drop across the isolators can be up to 1 volt on cheaper models and will prevent your battery from getting fully charged.

While this may never lead to cranking problems, in the majority of the time it will lead to shorter battery life and its just another device that is really not needed.

The redundancy of cross wiring the charging systems to charge everything off one systme is just silly given the reliability of altenators today and battery chargers.

By using battery switches you get the full charging voltage and the ability to manualy control your charging.

The house battery is normaly hooked up to the shore charger. So when leaving the dock, it has a full charge and a fully charged properly sized battery for your load will provide power all day without the need for additional charging.

By putting in a 1/2/both switch to one engine or another it gives you the ability to charge the house from an engine if you decide to do an over nighter without the voltage drop of an isolator.

Remember the kiss principle, it will serve you well.

wmachovina · Post by **wmachovina** » Feb 5th, '09, 07:38

I used two 4d glass mats ,port and stbd engines, port also serves as house, and stbd handles its engine and three bilge pumps, port handles extra bilge pump. all can be coupled with manual battery switch. nothing auto( except pumps). Just cranking 454s

IRGuy · Post by **IRGuy** » Feb 5th, '09, 10:54

Bruce...

Thanks for the advice. Actually at the present time my house battery is wired as you suggest, being recharged only by shore power. I have considered installing an isolator so one engine can recharge it after it has recharged it's starting battery, so I can always be sure of having everything recharged, but a manual switching system makes a lot of sense (as long as you don't forget to make the switch changes!).

Mikey · Post by **Mikey** » Feb 5th, '09, 11:33

<a href="http://s187.photobucket.com/albums/x54/ ... 010003.jpg" target="_blank"><img></a>
Installed these much lighter batteries in the cabin bilge to power electronics and start two Cummins. Does the job admirably while being lighter and at a low center of gravity. Usually this space isn't used anyway so good solution.
Not sure why the image has decided not to post, click on it.

John F. · Post by **John F.** » Feb 5th, '09, 12:46

Nice job Mikey. Neat wiring.

John

daydreams · Post by **daydreams** » Feb 5th, '09, 19:52

WOW, its amazing all the really good options. I'm going to ask a few questions and then read this post 3 - 400 times before I will be able to decide which way to go.

Should all 3 neutrals be joined no matter which set up?
Should the neutrals at the block go to bonding?

If one engine starts from a pair of batterys [1-2 or both batt switch] but charges the house battery only does that batterys neutral go the that engine block?
I believe that usually the alternator charge wire goes to the batt on the equipment side.
But in this situation the alternator should go between the battery and the switch to prevent forgetting to turn the switch on and causing alternator damage?

If 1 batt did port engine and bank -#1 batt did SB engine and #2 batt did the house would the neutrals be connected parallel?
I like the solenoid jumper idea. I expect to work that into my system

Mikey nice batterys. I have water tanks in that area. those must be the gel batts no fumes. nice job.

Ed what is a combiner?
Thanks everyone your time and info is very much appreciated.

daydreams · Post by **daydreams** » Feb 6th, '09, 06:20

opps, I was laying in bed at 4:00 AM thinking its to early to get up and I realized that I called the battery negitive / neutral. I figure it's due to stress, a senior moment or just thinking too far ahead. I'm going with the latter.

Charlie J · Post by **Charlie J** » Feb 6th, '09, 06:40

my 4 girls ops 3 girls has 3 sets of batts, 1 for each engine and a 4 d for the house 4 set of switches so i can back feed any way possible. 3 bank charger is connected directly to each batt

Harv · Post by **Harv** » Feb 6th, '09, 09:19

Hey Charlie,

good thing you didn't put the name back on the transom after your paint job.

Mikey · Post by **Mikey** » Feb 6th, '09, 11:03

If you are not using your boat for overnights on a regular basis why do you need fresh water tanks? I carry jugs and find this more than sufficient. That's why I eliminated one water tank. The other I am contemplating using for waste from the head.

IRGuy · Post by **IRGuy** » Feb 6th, '09, 11:21

Bruce...

Re: Your post above...

When underway and you want to manually change the alternator's output to charge another battery do you have to shut down that engine so the alternator won't suffer any damage?

Maybe a dumb question but better to expose my ignorance here than later at sea.

randall · Post by **randall** » Feb 6th, '09, 12:29

mikey...i use the water tank ,in a dinette bench, to balance the boat....it likes to lean to starboard and i can adjust pretty good with the water tank. plus...if you have a galley faucet...its nice to have something come out of it.

Rawleigh · Post by **Rawleigh** » Feb 9th, '09, 09:15

Fresh water washdown to follow the hot saltwater washdown.

Mikey · Post by **Mikey** » Feb 9th, '09, 09:39

Randall,
I used some lead (tire weights) to balance the boat. They all seem to list to starboard. Think they must have anticipated gensets.
Rawleigh,
Fresh water washdown at the dock. Don't need the extra weight. It may not be much but . . .
This is what's interesting about this group, variety of thought. Through the years that I spent renovating Dreamsicle I asked many questions and got as many answers. I think the results to date are pretty impressive and all due to the many different thoughts on any subject.
Keep'em coming!

bertram31.com

battery & wiring questions

battery & wiring questions

Who is online