Car Battery for Simple Electrics?

[aquaplane]

Aquaplane, First 18, didn't have any power at all. I fitted a car battery in a fastened down box so I could have a VHF. I used a simple panel like the one you looked at with the fag lighter socket but just 4 fuses, no fag lighter.

I had no nav lights and no interior lights, except a storm lantern, and the battery lasted about a week with frugal use. I went to bed when it got dark, quite late in Scotland. Pi$$ poor charging from the outboard.

Carousel, Copland 20', has lights, VHF and, well that's all. I got one of those 3 outlet tent hookups someone posted a link to. A night in a marina every 4 or 5 nights and the 240V battery charger tops up the battery. And the moby, and the camera(s). No charging from the outboard.

Sometimes I think you can spend more money looking after batteries, making them last longer, than they are worth.

 

[paul.norton]

I sometimes wonder if it's only the label that's different

Anyone care to comment on this: http://www.sterling-power.com/support-faq-2.htm

Paul

 

[Lakesailor]

What a load of pontificating.
I use a car battery for my fish finder. Two small crocodile clips with a fuse in one lead.
Lasts months.
Take it home and charge for a night.

 

[wytco0]

I sometimes wonder if it's only the label that's different

Anyone care to comment on this: http://www.sterling-power.com/support-faq-2.htm

Paul

Yes its excellent.

 

[Plevier]

I sometimes wonder if it's only the label that's different

Anyone care to comment on this: http://www.sterling-power.com/support-faq-2.htm

Paul

There is an awful lot of good sense in it about conventional and "leisure" batteries BUT he is wrong to lump gel and AGM batteries together. Good quality AGM batteries (there are lots of poor quality ones around) do accept charge faster, if correctly treated do not gas and can give decent cycle life. Some on this forum would say as good cycle life as flooded batteries but I'm not yet convinced.
Gel batteries are not appropriate for fast charge and are more prone to water loss than AGM. In general that makes them undesirable for boat applications.
"Leisure" batteries in general will have slightly thicker plates than starter batteries and extra separators. Worthwhile but as he says, it doesn't turn them into real deep cycle batteries. In some cases VicS's cynical comment may be justified. "Leisure" doesn't have an accepted industry definition.
I agree Sterling's overall conclusions except I would say go for AGM if their quick charge, non-spill and no topping up advantages justify their price to you. It's a personal choice.
I make these remarks as a former manufacturer of both flooded and AGM (high quality of course ) batteries and therefore not one of Mr Sterling's favourite people!

 

[electrosys]

What a load of pontificating.
I use a car battery for my fish finder. Two small crocodile clips with a fuse in one lead.
Lasts months.
Take it home and charge for a night.

OP: "I would be running the echosounder, anchor light and possibly nav lights off it."

And that's how it starts ... then add a computer, and maybe a VHF ...

 

[Lakesailor]

Yeah....and then a microwave.

Simplify your life.

 

[William_H]

Small boat batteries

Firstly yes OP needs LED nav lights. Then yes the old battery will probably do fine for some time. And yes as said a single fuse near the battery terminal is all he needs. + switch for lights.

However just for a completely different approach. I love NiMh batteries.I use them at home for security 12v lighting charged daily by a small solar panel. In D size you can get 11 amp hour and even cheaper for power you can get 6AH Sub C batteries with tags. You need 10 of course to make 12v. I put them in a small lunch box with a fuse. The advantage of NiMh apart from much lighter is that you can happily discharge all of the AH. So 6AH is equal to 12AH lead acid. About 10 squid will get you 6AH and you could parallel to sets to give 12AH for 20 squid. This is waht I will use on boat when present battery expires. The D size seem more expensive for the capacity than Sub C and the sub C having tags can be soldered together. (Ebay from China of course) Just a thought olewill

 

[reeac]

I have a wooden dayboat which needs regular [weekly] pumping out - due more to rain than leakage this summer - and I have a Lucas sealed 12v., 12Ah. leisure battery which is intended for use in a mobility buggy. It will do a season's duty without recharging but its weak point is its fragile brass terminals as I use croc. clips to attach and detach it from the free-standing bilge pump.

 

[nigelmercier]

I use croc. clips to attach and detach it from the free-standing bilge pump.

Why not just make up a lead with a plug and socket?

 

[electrosys]

I use a car battery for my fish finder.
Lasts months.
Take it home and charge for a night.

But bear in mind that it's a trailer-sailer, NOT a day-sailer.

So, let's do some sums ...

It *was* a 60AH battery - let's say it's good for 40 now (?) - allowing halfway discharge, that gives 20 Ampere Hours 'running time'. Over-simplified ? Sure.

Anchor Light/Nav Lights (say 0.5A for 10 hours ?) - that would suggest around 4 days between charges, using my very last functioning brain-cell.

Is that enough, bearing in mind that it's always good to have something in reserve ? Only the OP knows the answer to that one.

 

[KellysEye]

Car batteries are cranking batteries designed to put out lots of amps for a short period. Light, depth sounder etc take out a relatively small amount of amps over a long period of time thus need deep cycle batteries, as used in golf carts. Trojan batteries are an example.

 

[Little Rascal]

If you go armed with a suitable portable battery charger you may find one of these
http://www.towsure.com/product/Mini_Mobile_Mains_Unit
or
http://www.towsure.com/product/Camping_Site_Mains_Supply_Unit_3_Outlet

useful to connect to the marina shorepower when available. Both incorporate an 2 pole mcb and an RCD

Coming back to this thread after a long time...

Sounds silly but having never used it: what is provided when you have shore power? Just the hook up point? Presumably you bring your own cable?
I'm seriously thinking of getting one of these http://www.towsure.com/product/Mini_Mobile_Mains_Unit

Thanks!

 

[ostell]

Yes you plug into the socket on the pontoon. The item you are thinking of using, the single unit, only has a 10 metre lead. How long is your boat? Bow in and lead back to the companion way uses the length of the boat at least and then from boat to pontoon and then to the nearest socket, which could be some distance away, using a safe route so that nobody trips over it. Go for the 3 socket version with the 20 metre lead. Looks like the same price at the moment.

Last week, if I had plugged in, I reckon I would have needed a 16 metre lead

 

[jwilson]

I know some trailer sailors who use a car battery and actually run said battery in a the car except when they hoick it out and into the boat for the weekend expedition.

I did this for years in a small yacht: used to park my car on a slope so if I did flatten the battery after few weeks away I could bump-start it. Used only for low-wattage tricolour nav light, compass light and and one 12v fluorescent tube in the cabin. Rest was oil lamps, and eventually the decadent luxury of a spinning-neon echo sounder to replace the leadline.

 

[William_H]

Yeah things to consider are the weight of the battery and convenience to remove and replace if you are going to remove it for charging. Solar panel may solve all these problems. Certainly a car battery is not the most efficient at storage for low current use for its weight but if you can cope with the weight and have the battery why not.
Certainly even since this post started LED are for more common and cheap so current demand falls. olewill