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Battery Isolator Wiring


ffdawg

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I'm trying isolate my batteries so one of them is reserved for starting ONLY (battery #1) and the other will run ALL accessories (battery #2). The previous single battery setup had 2 ga positive and negative cables running from the alternator to the battery and 6 ga positive and negative cables running from the battery to the positive and negative distribution blocks. My question is if I connect the 6 ga cables to battery #2 won't the ignition, starter, etc. be getting their power from that battery and not #1? I know that when I do not have the 6 ga cables hooked up the ignition does not work, therefore they are not just accessory cables.

My fear is that I will completely run battery #2 down and not be able to start the engine. Hope this makes sense. Thanks.

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Purchase a battery isolator/combiner.. like the Hellroaring unit http://www.hellroaring.com/bicfaq.htm

Then you'll have the separate, but charge together. If you do drain down the accessory battery so much that the ignition doesn't work, then simply disconnect the positive connection to the dead battery, and connect it to your starting battery - and walla! You're back up and running.

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I'd guess that you would have to add a separate positive and negative distribution blocks & identify and relocate all the ignition components to the starting distrubion blocks & leave the accessories on the current distribution blocks.

You will need some power to the ignition key to enable the starter solenoid to put the power from those 2GA cables to the starter - also to fire the spark plugs, MDC, guages & fuel pump system until the engine starts and possible more (Bilge blower for safety).

You may be better just moving the accessories you want isolated (Stereo, lights, bilge?) instead of trying to identify all the necessary systems for running the boat.

Probably more trouble than it's worth when isolator/combiner set-ups work so well.

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Yes, waaaaay to much work to isolate all the ignition, fuel pump, engine computer power from the main power-block. If you already have two batteries, you either need to get a perko- and switch manually, or a combiner/isolator that does it auto-magic-ly Yes.gif

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I just did install a Blue Sea 7600 Automatic Charging Relay along with two Optima Blues. This isolates the two batteries unless there is enough charging current, then the relay closes and both batteries are charged. With this setup, or a Perko switch, I was hoping to not have to worry about how long I ran my stereo, cause if I happened to run my accessory battery all the way down I would still have a fully charged starting battery ready to go and could fire up the boat without having to manually disconnect anything from the dead battery and connect it to the good one. However, I'm finding it difficult to seperate all the starting items (ignition, fuel pump, etc.). Unless I can somehow get them seperate, they will have to run off the accessory battery along with the stereo and all other accessories, I guess, because I don't want anything running off the starting battery - that would defeat my purpose of having the batteries isolated.

So unless I want to go through with what sounds like quite a bit of work to seperate the starting items I will have to manually move them to the starting battery if my accessory battery goes dead. If my understanding is correct?

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Why not just run all the stereo stuff off the accessory battery (and maybe nav/tower/interior lights) & run everything else off the starting battery? They way your are describing it right now, you would be stuck dead if either of your batteries drained entirely.

You also set it up to use a perko to combine the batteries for starting everything if you ran it down with the stereo or other accessory. (Pardon the drawing, it was a quick 'Paint' throw together.) You'd still charge with Blue Sea like it is now & would generally leave the perko switch on ONLY the accessory battery. If you fully drain the accessory battery, then either switch to the other or combine them to get going. Once running & sufficiently charged, switch back to accessory battery only.

post-1242-1176932311_thumb.jpg

Edit: add last 3 sentences.

Edited by weinrdog
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Why not just run all the stereo stuff off the accessory battery (and maybe nav/tower/interior lights) & run everything else off the starting battery? They way your are describing it right now, you would be stuck dead if either of your batteries drained entirely.

You also set it up to use a perko to combine the batteries for starting everything if you ran it down with the stereo or other accessory. (Pardon the drawing, it was a quick 'Paint' throw together.) You'd still charge with Blue Sea like it is now & would generally leave the perko switch on ONLY the accessory battery. If you fully drain the accessory battery, then either switch to the other or combine them to get going. Once running & sufficiently charged, switch back to accessory battery only.

post-1242-1176932311_thumb.jpg

Edit: add last 3 sentences.

I agree with you on this.

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Thats the way I had planned on wiring mine...but not sure the inline fuse is necessary? I will be installing a Stinger 200A relay on Saturday. But am also likely going to need to extend my wire so I can put the bats under the observer seat, so maybe adding an inline fuse will be a nice of adding length to it? Dontknow.gif

I know a fuse is hardly EVER a bad idea, but is it necessary on that end?

Here's mine, Stereo on Battery #2. Everything else on #1. Works for me.
Edited by WaveMake'nLSV
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Thats the way I had planned on wiring mine...but not sure the inline fuse is necessary? I will be installing a Stinger 200A relay on Saturday. But am also likely going to need to extend my wire so I can put the bats under the observer seat, so maybe adding an inline fuse will be a nice of adding length to it? Dontknow.gif

I know a fuse is hardly EVER a bad idea, but is it necessary on that end?

Here's mine, Stereo on Battery #2. Everything else on #1. Works for me.

Theres a fuse/breaker on your stock set up so why not put one on your after market just incase. I think Stinger also makes some nice fuse blocks and breakers

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