golf kart batteries

[d design]

Will two 6v golfkart batteries be reliable enough to use as a starting and house battry? Biggest power draw will be the max 1kw starter motor of yanmar 1gm10. Surely those golf karts have more than 1kw motors!? Im trying to avoid expensive complicated charging relays, conections, and wiring to increase reliability. cheers

[gonesail]

they are fine for starting small motors .. trojan even says so. we had 4 GC batteries for a yanmar 3GM. 2 should be good for your 1GM.

[djmarchand]

gonesail is correct. But the purpose of a separate house and starting battery system is to allow the house to discharge while protecting the starting battery for when it is needed to start. You need two battery (banks) to do this.

David

[SVTatia]

Originally Posted by djmarchand

gonesail is correct. But the purpose of a separate house and starting battery system is to allow the house to discharge while protecting the starting battery for when it is needed to start. You need two battery (banks) to do this.

David

++ 1 on that.

They can be the start battery but you want redundancy for when one bank is down and things hits the fan you have an alternative for your engine, bilge pumps, etc.

[Stu Jackson]

Google "Maine Sail" and read his writeup of how much starting an engine really needs. It's TINY - whoops, shouldn't have used capitals.

You'll be just fine.

The entire issue of having a separate reserve ( or start) bank is an entirely separate issue.

If you choose to do so, then try these:

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

[SVTatia]

Originally Posted by d design

Im trying to avoid expensive complicated charging relays, conections, and wiring to increase reliability. cheers

It doesn't need to be complex or expensive, it just needs to be safe. Please read this excellent post...

1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

Stu was faster than I....

[roverhi]

It doesn't take much of a battery to start a 30hp or less diesel. Two golf cart batteries pack way more energy than is needed. The problem with only one battery bank is inadvertently letting the battery(ies) discharge, BTDT. Fortunately had a hand crankable diesel so was able to get the engine started and charge the batteries back up.

FWIW, if you ever do find your self with weak batteries, sail downwind with transmission in forward. The water flowing over the prop greatly cuts down the energy needed to turn the engine over.

[d design]

My engine has a decompression lever and a hand starter which I have sucesfully started the engine with. Only thing with the separate starting battery is it eliminates high/low voltage spikes from acessories but based on the size of batteries, it shouldnt be a problem.

[FSMike]

Originally Posted by d design

----
Im trying to avoid expensive complicated charging relays, conections, and wiring to increase reliability. cheers

If that's what you want to do one 12 volt battery has fewer connections than two 6 volt batteries.

[roverhi]

Originally Posted by FSMike

If that's what you want to do one 12 volt battery has fewer connections than two 6 volt batteries.

Yes, except to get the amps of two 6v GC batteries, you need a honking big 12v battery. A battery that is way too heavy for my back to handle when moving it becomes inevitable.