separate battery

[yamp]

just got into rewire job on old mans hooker 5m, wiring was a bit messy and had to follow,problem was the furuno sounder plotter would drop out when you cranked the battery,spoke to furuno and was advised to run separate battery for sounder only,does any one actually do this? the boat currently only has one battery for starting and bilge,deck wash etc,the boat has a 1 2 both switch , thought could wire in second battery,either a small stand alone 7amp hour or second battery off the switch,just after any advice on best set up cheers Yamp

[Xahn1960]

I run 3 batteries; 1 for motor and bilge, 1 for electronics, and 1 spare ( not needed but has come in handy :) ) I find this works well for me, may sound like overkill but I've never been stuck with a flat battery or problems with the electronics...

Bill.

[foxx510]

If you do add one, you really need to stay with a wet cell type battery, if you use a small 7ah gel cell it won't like the charging current supplied by the motor and wont last real long.

[Chimo]

Its worthwhile having your electronics operating of the "house" battery that is isolated from the starting / "spiking" battery.

I was told this by Lowrance when they replaced my GPS/Sounder which lost pixcels due to engine spikes when starting.

Fit an auto battery coupler to keep the house and electronics isolated from the motor. The little battery would be a waste of time.

Or do nothing and replace your electronics often.

Cheers
Chimo

[FNQCairns]

Honest if your battery is big enough and in good condition it should never drop the sounder or any other equipment out, I have never had this problem that couldn't be trace to something out of spec.

I would also check resistance of everything at the battery.

Also as a thought, do you have the take off for the sounder at the battery terminals? if not and you have it elsewhere like on the ignition?? regardless if from the terminals it simply shouldn't drop out.

cheers fnq

[yamp]

thanks for replies fellas, I was thinking about the 1 2 both switch and was thinking about the spiking issue,you would have to be carefull electronics are not switched on when starting outboard, I have never ever really been worried about it on my tinnie step up but only had problem on old mans setup, fnq I think will probably be some sort of voltage drop type problem see what happens after rewire, chimo was is the auto battery coupler about sounds like it might prevent the spike problems, my thinking with the 7 amp/hr battery would be just charged of 240 charger at home not hooked up to battery switch,which would be a pain

[Hornet Rider]

thanks for replies fellas, I was thinking about the 1 2 both switch and was thinking about the spiking issue,you would have to be carefull electronics are not switched on when starting outboard, I have never ever really been worried about it on my tinnie step up but only had problem on old mans setup, fnq I think will probably be some sort of voltage drop type problem see what happens after rewire, chimo was is the auto battery coupler about sounds like it might prevent the spike problems, my thinking with the 7 amp/hr battery would be just charged of 240 charger at home not hooked up to battery switch,which would be a pain

yamp, I'm no expert so blend that with the option I've adopted. I was experiencing my Lowrance 525 sounder dropping out on start up. Thought it was a wiring problem, but spoke to one of their techs & said unless the wiring was isolated from the possibility of spiking when cranking the motor then the sounder is unguarded against spikes, & hence damage, ie loosing pixels or worse. I then adopted the procedure of switching off the sounder on the switch panel, start the motor, then switch the sounder back on. No problems with that sequence. Last week I fitted dual batteries, a quality Bluesea marine switch (ie 1,2, Both, Off) (http://bluesea.com/category/1) & used the wiring diagram attached. Chimo has a very sophisticated electrical system for his Seafare Vagabond with twin ETecs. I've examined his set up as he explained in a detailed thread on here, & decided to fit for something more basic because I only run one engine & my trips are not overnight or longer. It's always a toss up if you have a smaller boat to fit at least two batteries. I'm a fan of redundancy so for me the choice to fit a second battery was simple, it just took me too long to get around to it.

[steveg1100]

They know the environment when they build these things you would think they would have a good enough design that the starting currents would not bother them. They need to up there game. Look at the electronics in a car these days. How many cars have a second battery so that the starting surges does not effect the computer, efi, radio, gps etc?? I think the answer is none.

[Fed]

Wiring a small battery to your 1-2-Both switch won't help you at all.

Pos 1 = Same as it is now.
Pos 2 + The small battery won't start your motor.
Pos Both = Marginal (Nil) help if your big battery is no good.

If your electricals are all up to scratch it won't drop out.

[krazyfisher]

I have only had this problem when the battery was not big enough or was getting down in charge

[Hornet Rider]

yamp, I forgot to mention that I run 2 x champion hvy duty 4x4/marine batteries, both about 770 CCA

krazyfisher, low battery power was the other reason the Lowrance tech advised would cause the sounder to drop out. Mine did it both on normal start up with a fully charged battery & also one night on a low battery (11.4v) after a day of drifting, lots of start ups & then small run ups. Not enough to recharge the battery & then used the nav lights, deck lights.

Fred, 'If your electricals are all up to scratch it won't drop out.' yamp said he was having problems with his furuno dropping out. Don't know anything about furuno's but my electrics were good & my lowrance was dropping out on normal crank/start-up & also on low battery. The low battery drop out is mentioned in the manual, as a protection system on the sounder. The lowrance tech suggested fitting a surge protector, but I decided to use a manual one, ie turn the sounder off at the switch panel, not at the head unit, before start-up. Works for me.

[black runner]

They know the environment when they build these things you would think they would have a good enough design that the starting currents would not bother them. They need to up there game. Look at the electronics in a car these days. How many cars have a second battery so that the starting surges does not effect the computer, efi, radio, gps etc?? I think the answer is none.

Motor vehicles have additional voltage regulators for dash equipment and also in most cases current is cut to accessories (via the ignition switch) during the cranking phase.

Cheers