hi i have a boat with a v140 yamaha and want to run two century 660ccaidentical batterys together to help the starting ,not because one on it self wont start it but because i think linked they will both charge at the same time and just give it the xtra little bit of grunt when winding over and run the fishfinder etc.can someone please advice me of what leads i need to do this cheers
unbeatabull,
Jul 18, 8:18am
Id imagine you will want to run them as parrelel for what you want to use them for, so basically split the Positive lead into two and run one to each battery and same for the negative.
geminidragon,
Jul 18, 8:21am
is there a wiring diagram for parelell and where do you buy these short leads please
thewomble1,
Jul 18, 8:23am
connect positive to positive and neg to neg will give you 12v. not sure if it is a good idea to charge as one unit.
tonyrockyhorror,
Jul 18, 8:23am
Better to get a deep cycle to run accessories with a switch and smart charging relay. They have a starting rating too for use in an emergency but handle long duration low discharge rates much better than a starting battery will.
fryan1962,
Jul 18, 8:24am
positive to positive then same wiring as there now
negative to negative then same wiring that is there now
which will give you 12 volts
geminidragon,
Jul 18, 8:27am
i had one good 15 plate 600 cca marine battery when i bought the boatbut they dont like sittingand i,ve taken these ones out of my truck hoping they would suit
geminidragon,
Jul 18, 8:30am
if i putpos to pos then neg to neg what terminals am i left with to connect power for outboard to ,i,m confused
fryan1962,
Jul 18, 8:33am
hook up to boat as normal, then buy two cables to link new battery to first battery,taking care pos to pos ,neg to neg
pdc1,
Jul 18, 9:32am
It's a boat. You can't just get out and walk. If you have two batteries, don't just permanently parallel together. If something accidentally gets left on, then both batteries will be drained at the same time. Spend a little extra and fit a system that parallels the batteries once engine is running. That way you have 2 separate batteries, and a much higher chance you will never have both flat way out at sea. Plenty of different systems out there. Some have the option to manually parallel as well.
No insults intended, but I would suggest going and seeing an marine or auto electrician. It will be money well spent ($200 or $300!)
etimret,
Jul 18, 9:38am
Hi just get 1 marine battery . It is part cranking and part deep cycle. grandad had the same problems on his boatbut no longer
gammelvind,
Jul 18, 9:52am
Just leave the existing connection where it is and with new cables connect the extra battery to the same connections, pos pos neg neg. As mentioned above this will only give you extra capacity but if you let it go flat then you still won't start. Best if you can have the battery that the fishfinder runs off switched out while engine not running.
geminidragon,
Jul 18, 10:17am
understood thanks for all your help fellow fishos:)
sr2,
Jul 18, 10:32am
Easiest way is to use a voltage sensitive relay (VSR) to connect both batteries (it??
mike77,
Jul 18, 10:41am
I wouldn't wire them in Parallel like the above.
Being in a boat, ( and this advice is on the assumption your not purchasing a smart charging system) you want an switch that can select either battery or both. (1, 2, both, off) This allows you to start with one, charge both whilst running, thus always ensuring you have a good battery.
Wiring them both permanently in parallel means you have no idea, how much drain you placed on the battery bank, and you have no redundancy. Also if one battery is screwed it will quickly drain the good battery until they are both screwed. Then you have to replace both.
Also, I wouldn't bother with a deep cycle battery unless in intend to spend consequtive nights on the boat. If so add up the wattage of your appliance'sand the time you need them to work for and covert to amp hours, to work out the size of battery or banks you need.
mike77,
Jul 18, 10:45am
Just read pdc1 post, just like he says.
Also, if your unsure of what parrallel is, it is definately advisable to go to the boat shop and pay the man, just don't get caught on the upselltrying to get you to pay for those smart charging systems.A switch is basic, and it works 100% of the time.
mike77,
Jul 18, 10:45am
Just read pdc1 post, just like he says.
Also, if your unsure of what parrallel is, it is definately advisable to go to the boat shop and pay the man, just don't get caught on the upselltrying to get you to pay for a VSR or similar.A switch is basic, and it works 100% of the time.
geminidragon,
Jul 18, 12:30pm
thanks mike77
johnf_456,
Jul 18, 9:10pm
Good advise :)
I would also recommend a deep cycle battery for the accessories, they handle been run flat a lot better.
pdc1,
Jul 18, 9:34pm
Some people may suggest a diode for charging the extra battery. Personally I would stay clear of this, as you won't get the best charge into the battery through the diode. On my boat I use a relay system through a oil pressure switch, that parallels the batteries once the motor gets oil pressure (straight away).(not suitable for 2 stroke) I also have wire a master switch to parallel the batteries manually, if needed. You could just carry a set of jumper leads to do this in emergencies if you wanted. The VSR voltage sensitive relay is as it sounds, a relay that parallels the batteries once the first battery reaches a pre determined voltage, so basically the paralleling won't happen until the battery has a good charge into it. As another has suggested you could fit a manual switch between. THis will work fine, if you are the only one to operate the boat, but you have to remember to switch it on and off to get the full benefit of having 2 batteries. and this is a easy part to forget on a boat when you are arriving or leaving a destination. If you do go for a manual switch, again jumper leads may work for what you want to do, without having to spend much.
fryan1962,
Jul 18, 9:50pm
it all comes down to cost / money you could make up small set of jumper leads, hook second battery up for starting. leave connected for a while so it gets charge.then drop one of the jumper leads off and there will be no drain
hopie,
Jul 18, 9:53pm
as stated above Pos to Pos Neg to Neg for 12volt. Hooking it up the other way Pos to Neg and Neg to Pos will give you 24 volt.
tonyrockyhorror,
Jul 18, 10:04pm
Looks like we're all pretty much in agreement. Now that's a first.
hopie,
Jul 19, 12:18am
i disagree
Now don't quote me on this, google it before hand but im sure you hook up your cables POS to one battery and NEG to the other battery.
Mike77 is 100% correct on a dead or flat battery draining the other one. Switch idea is good advice!
elect70,
Jul 19, 1:49am
The charge system may not be up to 2big batteriesAs prev say use1 formotor t &for auxillarysthats the way it is onbig boats,If 1 is a bit oldcan alwayscarry jump starter pack . Thats a bigmotor so needsfull batteryvoltsnot 2half chargedones
Since the public registrations are closed, you must have an invite from a current member to be able to register and post in this thread.
Have an account? Login here.