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Last Cast
06-04-2008, 01:22 PM
Would like your thoughts on placing a pair of AGM Batteries under the seats about the midline of a 16' half cab glass boat. I am trying to get some weight a little forward because with the motor weight & 50 ltrs fuel & a dual battery setup at the very rear of the boat she's a little ass heavy. 145kg motor,50 kg fuel & 46kg batteries. (241kg total) Another question about getting some weight forward do you think the boat will get up on plane easier & at lower speeds doing this?

Vitamin Sea
06-04-2008, 01:54 PM
Hi

I did exactley what you are talking about doing in my last boat, it was a Haines 163C.

Put the batteries under the helm seat, keeps them dry, easy to get to, no problems.

The ideal would be to have a battery each side to keep even weight distribution, if you can wangle it.

Can't say I noticed any appreciable difference in geeting on the plane, but it stands to reason the more weight forward, the quicker it will get up.

Hope this assists

Cheers

Last Cast
06-04-2008, 02:04 PM
Thanks mate, one either side sounds like a great idea too. Any suggestions on how you would run the cable ie up around the bunks to get to the other side or come from the back of the boat? Also did the position of the batteries in the Haines reduce the lifespan any?

dnej
06-04-2008, 02:09 PM
Is there any problem,with power drop over that length?
It was suggested ,that my brother move the battery for the motor,closer to the motor,after a trigger coil went . He had a whopper of a cable,also,so I could not see the reason,for the recommendation.
Would really like to know ,as it would be great for me as well
David

Vitamin Sea
06-04-2008, 02:26 PM
Thanks mate, one either side sounds like a great idea too. Any suggestions on how you would run the cable ie up around the bunks to get to the other side or come from the back of the boat? Also did the position of the batteries in the Haines reduce the lifespan any?

Hi

I would not go all the way around the bunks etc, would end up with 4+ m of cable.

Directley across would be the way to go if you can, but would have to look at your layout to see how it could be done, just requires a bit of thought.

Running from the back would not work, you still have to "join" the 2 batteries.

I had the batteries 2 yrs + after doing it before selling the boat, they were still fine at that stage.

I have done the same thing in the present boat, which is a HH 19C, all good

Cheers

Vitamin Sea
06-04-2008, 02:27 PM
Is there any problem,with power drop over that length?
It was suggested ,that my brother move the battery for the motor,closer to the motor,after a trigger coil went . He had a whopper of a cable,also,so I could not see the reason,for the recommendation.
Would really like to know ,as it would be great for me as well
David

Hi David

I have not noticed any power drop at all, thick cable running from the back, heavy duty marine batteries, no problem.;)

Cheers

FNQCairns
06-04-2008, 02:35 PM
The only real drawback to me would be the extra hammering they will take when placed forward, it may cost you money and time (hopefully not offshore) than if they were place in the rear.

cheers fnq

Outsider1
06-04-2008, 02:54 PM
My car has its battery in the boot, I am sure plenty of others do as well. At just under 5 metres in length, I would suggest that it is comparable to the cable length you are talking about here, so I don't see it as a big deal at all, providing they are wired up correctly.

The issue would be more FNQ's point, what sort of extra hammering are they going to take being located amidships?

Cheers

Dave

BaitThrower
06-04-2008, 08:48 PM
Aren't AGM batteries less susceptible to hammering/angle issues though? I mean you wouldn't deliberately try to hammer the life out of them, but aren't the supposed to offer more protection than standard lead acid batteries etc etc in this regard? Or maybe I've just been interpreting the marketing hype incorrectly :)

oldboot
06-04-2008, 09:49 PM
Almost without exception, race cars and rally cars have the battery in the boot for the same reasons... weight distribution....some of the new standard cars have them in the boot too.......as long as the cable is heavy enough there arent any problems.

as far as vibration......I cant see that any boat would give a battery the sort of hammering it would get in a car on a corigated road....the AGM most cretianly should cope with the vibration better than a battery with open cell plates.

You do need to be carefull with the cabling.
large size to allow for voltage drop

protecting the cable from damage because if it is a start battery you can not fuse the cable.

I recon the recomendation to shorten the battery cable, after a failed trigger coil.....grasping at straws.......there are lots of people who can't cope with anything unconventional & will blame that for failures they can't properly isolate.

for cable, check out a good welding supplier.........remember you need positive and negative..........wont be cheap.

as far as the effect on performance.........try moving the missus from the front to the back of the boat.......unless she's a heavy weight that will be a similar weight transfer.

I have also heard of people mounting the fuel tank up the bow for better weight distribution too.

cheers

Last Cast
06-04-2008, 10:18 PM
Tried weight distribution with the missus up front & down back but found the boats balanced better with her left right out ;) Seems to have a dramatic effect on how quiet the Boat is too !
Thanks for the tips, you made a good point with the vibration i guess 4wd batteries have had to cope too.
Looked at moving the fuel forward but the V berth is too small, not sure i want to sit on it either, so thought the batteries might be the easier option.
Will speak to the sparky at work re voltage drop etc
Thanks to all for your replies it gives me something to work on
ps better keep the weight thing & my missus on the quiet!

viking08
07-04-2008, 02:58 AM
Cheers,
trying to get any info re weight distribution as I am the middle of removing well and replacing with a pod.
Voltage drop (more importantly crank amps) over 4.5m, provided good connection is negligible.
From what I have been advised put your money into extra (aux) fuel tanks .......

dnej
07-04-2008, 08:30 AM
Oldboot,
How many amps would a starter motor draw on a 90 hp Yammie,2 stroke?
David

dnej
07-04-2008, 06:55 PM
Old boot,are you out there
David

Vitamin Sea
08-04-2008, 01:45 PM
as far as vibration......I cant see that any boat would give a battery the sort of hammering it would get in a car on a corigated road....the AGM most cretianly should cope with the vibration better than a battery with open cell plates.


Good point

Cheers

Bill

FNQCairns
08-04-2008, 03:13 PM
as far as vibration......I cant see that any boat would give a battery the sort of hammering it would get in a car on a corigated road....the AGM most cretianly should cope with the vibration better than a battery with open cell plates.


Good point

Cheers

Bill

I dunno?

It's not vibration it's large scale sudden changes in direction thats the problem (hammering or slamming).

Vibration at the leisure of springs and shock absorbers, corrugations can make my bum feel numb after an hour or so but boating has been known in moments of inattention and in the blink of an eye cause my bum to bounce leave my seat fly through the air and occupy an entirely different portion of the boat:-[ not to mention sorely bruised if I even try to sit down to give my legs a rest from absorbing impacts.

cheers fnq

Last Cast
09-04-2008, 09:48 PM
Another good point, not sure where to go from here but i might try 1 agm battery up under the seat & see how it goes. Thanks to everyone for their tips & opinions, will fit one as i said under the seat on some sort of shock absorbant matting/ Rubber if i can get some, let you know how it works out :)
ps Spoke to Sparky at work & he Recomended 2b&s Cable to allow for any voltage drop over 6mtrs, said it was probably overkill but better safe than sorry for the little extra $$$

Blaster Bretty
11-04-2008, 06:55 PM
Mate I have my century marine battery way up front under the dashboard in my glass runabout, got a long cable and have had no issue's with loss of voltage etc,the reason its up there is to try and get the weight distributed a bit better coz the motor is a tad heavy, she's all screwed down and cant move at all, as we all know there is a heap more up and down left and right movement up front but marine batterie's are specially designed for this exact reason, the turbulence of the ocean travel etc. it is very important to keep the batterie's charge up though as letting them drain to the point of flatness is said to decrease the batterie's life. ive never had the battery located at the rear so I cant say if it planes better or quicker but I love having there coz its outa sight.

Bretty

Last Cast
12-04-2008, 10:25 PM
Thanks blaster , going to move em both up under the seats so now its just finding the time between work & play :)