batteries

dougal_22 · 15 February 2011, 16:02

hi all im after a bit of advise, all boats i have ever had have had standard batteries ie automotive style and never had any problems, now for my rib it will be bounced about a bit and my question is what type do i need, its for a mercury 20 4 stroke, in a valiant 380d sport

treerat · 17 February 2011, 21:02

I run a leisure batery in mine - bought from a caravan supplier at Highbridge.

Hightower · 17 February 2011, 21:46

You can buy "Leisure" deep cycle batteries that have good cranking amps too

9D280 · 18 February 2011, 11:43

There is a train of thought here that says it's a 20HP, therefore willprobably have a pull start for emergency use and I bet it is "self sustaining" (i.e doesn't need the battery to stay running once started).

My rib came with a super duper deep cycle heavy duty etc etc battery that I discovered would cost about £120 to replace like for like. One batt failure halfway through helping out at an event and a trip to the local Halfords for their £40 cheap N cheerful battery to keep it all going & I've not had a problem with it since.

A 20Hp won't pull anything like the cranking currents that some of the bigger three figure horsepower machines draw when the key is turned.

I suspect this will cause all manner of "you can't do that" kind of replies, but for a smaller engine in a sub 4m rib, there's almost an argunment for using a motorbike battery & keeping the weight down.

Starovich · 18 February 2011, 12:27

Quote:

Originally Posted by 9D280

there's almost an argunment for using a motorbike battery & keeping the weight down.

Agreed. my 1150 cc 80hp boxer Mcycle engine can be started on a bike battery then a modern smaller outboard would be no sweat.

Nos4r2 · 18 February 2011, 23:30

Quote:

Originally Posted by Starovich

Agreed. my 1150 cc 80hp boxer Mcycle engine can be started on a bike battery then a modern smaller outboard would be no sweat.

Yep, for sure. However, the dimensions of a bike battery may make it hard to keep upright and gel batteries are very expensive.

Starovich · 19 February 2011, 11:14

lots of battery boxes out there that can be bolted to a seat or console, remember, bikes in many cases get to much more extreme angles of lean than most boats,so the needs are similar.

Poly · 19 February 2011, 20:08

Quote:

Originally Posted by 9D280

There is a train of thought here that says it's a 20HP, therefore willprobably have a pull start for emergency use and I bet it is "self sustaining" (i.e doesn't need the battery to stay running once started).

My rib came with a super duper deep cycle heavy duty etc etc battery that I discovered would cost about £120 to replace like for like. One batt failure halfway through helping out at an event and a trip to the local Halfords for their £40 cheap N cheerful battery to keep it all going & I've not had a problem with it since.

A 20Hp won't pull anything like the cranking currents that some of the bigger three figure horsepower machines draw when the key is turned.

I suspect this will cause all manner of "you can't do that" kind of replies, but for a smaller engine in a sub 4m rib, there's almost an argunment for using a motorbike battery & keeping the weight down.

I use a "jump start pack" which I've 'hard wired' into the boat for my 20HP. Its worked for quite a few years with much neglect and long periods of not being used. Has the bonus of having an isolator switch, plus switched 12 V socket and voltage gauge etc all built in for the same cost as the cheapest battery Halfrauds has in stock!.

Nasher · 19 February 2011, 20:21

I have two Halfords car batteries in my RIB, an 80AH and a 110AH.

Both are still going strong after 5 years, even with long periods of non use, plus with the Halfords guarantee you can take them back within I think 2yrs if they give up.

I'd suggest the smallest one on the shelf would be suitable.

As already suggested I'd also have a look at motorcycle batteries.
If the tiny battery in my Z1000H can start the old dinosaur it would start your 20HP outboard.

Nasher.

rayfish2 · 19 February 2011, 21:03

started a thread on batts last month, great advice.. went to car breakers came back with 2 in great nick, fully charged for 10 quid each, thanks boys..

Nasher · 19 February 2011, 21:16

Quote:

Originally Posted by rayfish2

started a thread on batts last month, great advice.. went to car breakers came back with 2 in great nick, fully charged for 10 quid each, thanks boys..

Good man

Nasher

willk · 19 February 2011, 22:39

Quote:

Originally Posted by rayfish2

started a thread on batts last month, great advice.. went to car breakers came back with 2 in great nick, fully charged for 10 quid each, thanks boys..

I'm gonna file this beside JW's dimmer plans. Genius!