Dual Battery Connection

[tholmes3]

I have a 1990 Mastercraft pro 190. I want to set up a dual battery connection so that when I run my radio for several hours, I can still have enough power to crank the engine. I have read up on connections and have decided on a parallel connection. I wanted to see what y'all thought and the best way to do so? I was thinking of the following, is this correct or what would you suggest?: (I also have a 2 amp battery maintainer I use to keep the battery full when on shore or trailered)<br /><br />+ bat 1 to + bat 2<br />- bat 1 to - bat 2<br /><br />+ cable from boat to bat 1<br />- cable from boat to bat 1<br /><br />+ bat 1 to + maintainer/charger<br />- bat 1 to - maintainer/charger<br /><br />(NOTE: I have also heard of attaching + bat 1 to charger and - bat 2 to charger, what does this do, what what is the difference from the above?)<br /><br />I am trying to figure out the best method to do a dual battery connection with minimum wiring (as a selector switch would require)<br /><br />Thank you,<br /><br />Tommy<br />tommyholmes3@sbcglobal.net

 

[Bondo]

Re: Dual Battery Connection

Without the Selector Switch,.......You could Still be left on the water with Dead Batteries........<br /><br />The Idea of wiring the Charger to Both batteries is to Force the charging of Both batteries.........<br /><br />Electricity takes the path of Least resistence,.............<br />That could lead to only 1 "Hot"(Fully Charged) Battery the way you're looking to wire it.........

 

[tholmes3]

Re: Dual Battery Connection

So, to have optimal usage of both batteries I would use a selector switch in which the alternator charges both batteries while underway. IE: Always use Bat 1 when starting engine, and bat 2 while not underway to run the accessories and while boat is running, have switch set to both or 1, to ensure I always have enoguh amps to crank the engine.<br /><br />I guess worst case, have an extra battery on hand and jumper cables or channel locks....?

 

[vipzach]

Re: Dual Battery Connection

I personally do not like the manuel switches, I don't like having to remember to switch it after I stop or start. I bought a combiner/isolator from bass pro, and many other places sell them also, iboats may even have them.<br /><br />It will keep the two batteries isolated from each other while the motor is turned off and when started it will charge both batteries. I have two batteries, just like what you want, one for starting the boat and one for electronics.

 

[JRJ]

Re: Dual Battery Connection

Two batteries and a manual switch works very well for me. I use battery 1 all day and battery 2 all day the next trip. Both my batteries stay charged. I don't run an electric trolling motor.

 

[carljh]

Re: Dual Battery Connection

I prefer the high tech method to charge my bass motor battery and always have the main battery charged even if I run the bass battery flat.<br /><br />From the manufacturers website:<br /><br /> http://www.antares.co.uk/products/asc_133.htm <br /><br />Split charge systems are commonly specified on vehicles to ensure that the engine start battery is protected from drain by auxiliary loads.<br /><br />The Antares system uses an electronically controlled high power switch which responds directly to the on-board voltage. It recognises the presence of the alternator and external power supply when fitted. It is also compatible with the new breed of electronic regulators and the new generation of 200A alternators<br /><br /> Key Benefits<br />12V or 24V versions<br />Simple to fit - does not require any connections to the alternator<br />No energy loss in the switch<br />140A or 200A versions available<br />Dual sensing to recognise charging on primary or auxiliary systems<br />Remote sensing option to allow fitting away from the primary battery<br />Heavy duty studs and enclosure construction<br />Designed to IP66 environmental conditions<br />e marked<br />Can be used in pairs to create a three battery system.<br /><br />My own opinion:<br /><br />Fit, forget and foolproof.

 

[salty87]

Re: Dual Battery Connection

i use a stinger relay to isolate the loads on each battery. the alternator charges them both, the engine/starter are connected to starting battery, stereo is hooked to deep cycle.<br /><br />there are pros and cons here as with all systems on a boat. con...the stinger relay drops the charge rate but it hasn't caused me any problems. pro...no switches to mess with.<br /><br />i bought it at a local stereo shop. you can find stinger by searching.

 

[cuzner]

Re: Dual Battery Connection

Hey Tommy, I like to keep things simple, my suggestion, wire it the way have listed, and instal a good make before break battery switch, and instal it where you can get to it without ripping your boat appart.I also have my electronics and cabin power wired to a dedicated fuse block, with their own wires to one battery only, but I did this more because it made things easier than to save battery power.<br /><br /> Jim

 

[tholmes3]

Re: Dual Battery Connection

Cuzner:<br /><br />If I wire it how I had listed, where would I install the break switch, and how does that work? Would I install the onboard 2 amp charger to the + of bat 1 and - of bat 2 to ensure equal charge?

 

[imported_Curmudgeon]

Re: Dual Battery Connection

I'd suggest you go to a professional before you burn something up. Batteries aren't difficult, but there're some protocols that are very unforgiving if not respected.

 

[rickdb1boat]

Re: Dual Battery Connection

I have run my radio for the better part of the day many times and not run my battery down . But I do keep a spare battery onboard when I go out just in case. If all you are looking for is insurance in case your main battery gives out, just have a good fully charged one on hand....

 

[vipzach]

Re: Dual Battery Connection

There is nothing complicated about the combiner/isolator that I bought. It already had the wires on it, you simply attached the wires to the two batteries, it was labeled, one for primary and one for secondary. <br /><br />A battery switch takes a little more effort. If you use a combiner you don't have to worry about running down your starting battery when you ran the stereo all day, because the two batteries are isolated from each other when the engine is off. If you ever forget to switch the switch after the boat is turned off, you can stil end up with two dead batteries.

 

[imported_Curmudgeon]

Re: Dual Battery Connection

.. because the two batteries are isolated from each other when the engine is off.<br /><br />What happens to the batteries if the charging source goes bad? I've yet to understand why anyone would have multiple batts that can't be isolated from each other or the power grid.

 

[salty87]

Re: Dual Battery Connection

Originally posted by Old Curmudgeon:<br /> What happens to the batteries if the charging source goes bad? I've yet to understand why anyone would have multiple batts that can't be isolated from each other or the power grid.

your example is about a charging going bad....what if your back-up battery goes bad and you need it? you're stuck too. at least having them both charged off the alternator is a better attempt at keeping them both fully charged. a battery that is getting used regularly and charged regularly is much more reliabe than one that just sits around never getting used.<br /><br />"what if the charging source goes bad?"...proper maitnenance, stuff happens. i know my relay gets used, the lake i live on is very social so rafting up and listening to tunes is common. in 5 years with this boat, the alternator hasn't failed me.<br /><br />here's the link to installation instrux for a stinger relay... http://stingerelectronics.com/tech_department/sr200_sr80 diagram.pdf <br /><br />it's very straight-forward and they're pretty cheap too.

 

[salty87]

Re: Dual Battery Connection

dupe

 

[vipzach]

Re: Dual Battery Connection

Originally posted by Old Curmudgeon:<br /> .. because the two batteries are isolated from each other when the engine is off.<br /><br />What happens to the batteries if the charging source goes bad? I've yet to understand why anyone would have multiple batts that can't be isolated from each other or the power grid.

Well duh.......the batteries will go dead! Pay attention to your volt meter on the dash when you start the boat. My batteries are isolated from each other until the alternator is charging and the primary battery is full!

 

[tholmes3]

Re: Dual Battery Connection

So, if I simply have a back up battery and the main battery goes dead, should I then jsut connect it to the main one with jumper cables, like jump starting? Or should I have a wrench on hand?<br /><br />Also, I was thinking that every so often, start up the engine and let it run for about 10-15 minutes. How long do you think a batter would last with just the radio running, hour or two?

 

[rickdb1boat]

Re: Dual Battery Connection

Thomas,<br />As I said in my earlier post, I have gone out and beached for the entire day many times and my battery never came close to going dead just running the radio. Granted, I don't have a super powerful system. Just the basic AM/FM CD player running 6 speakers. In my case, I have a pontoon boat, so I have easy access to the battery if I ever needed to swap the spare to get me going. Fortunately, I've never had to do that. I've never heard of a fully charged battery (Spare) going dead just by sitting there, as long as it's charged up once in a great while. Just the way I do it and it's worked out for 20 some odd years...

 

[tholmes3]

Re: Dual Battery Connection

Perfect. I always test my batter after disconnecting the maintainer. At least once a month I also use a gravity meter to test the specific gravity of the battery acid to see if the battery is still in good condition.<br /><br />Now, for the use of others, I have found out the followign from a mechanic/electrician who works on all sorts of stuff.<br /><br />If you want to increase the longevity of your system by adding another battery in a parallel system, do the following:<br /><br />+ bat 1 to + bat 2<br />- bat 1 to - bat 2<br /><br />+ terminal form boat to + bat 1<br />- terminal from boat to - bat 1<br /><br />+ lead from charger/maintainer to + bat 1<br />- lead from charger/maintainer to - bat 2<br /><br />Now, if it is feasible, by way of cable connectors, connect the positive from the boat to bat 1/2 and the negative from the boat to the other. This would ensure that when charging by the alternator or the maintainer, there is equal distribution of amperage, though in a maintainer of 2-5 amps, it is so negligible, it should not matter. If you can not connect the terminal leads from the boat to different batteries, that is fine to, but the second battery might not reach a full charge by way of the alternator.<br /><br />With this set up, you have double the life of the "battery" which in this parallel set up joins the two 12 volt batteries into essentially one.<br /><br />If this seems incorrect, please let me know. I have just found this out and it seems possile and valid, but I would hate to hurt the electrical system of my boat.

 

[imported_Curmudgeon]

Re: Dual Battery Connection

..at least having them both charged off the alternator is a better attempt at keeping them both fully charged.<br /><br />And if the alternator goes bad both batteries may become uncharged very quickly. Exactly what happened to some folks off CHS last fall; I understand it was a long, cold, and hungry night.<br /><br />No system can be made "stupid" proof, but they surely can be made "stupid". Insuring fully charged batteries is merely a matter of moving the switch; insuring at least one good battery is merely a matter of never connecting 'em, except for emergencies, and going home when the the first one falters. More complicated than that just opens the door for that "stupid" thing.