Boat Batteries

[DavidJ]

I need to replace two of my port engine batteries. These batteries are only used to start the port engine. The other bank of batteries are used for the starboard engine and ancillaries. My conscience says I should buy the expensive gel deep-cycle/cranking type but I can't really see why I can't buy the same cheap lead acid as I have in my 4X4 which goes at far steeper angles than my boat.
I really don't have a problem topping up with distilled water twice a year.
Another thing, because of location I do leave my boat and batteries unattended and uncharged for 6 months over the winter. Is any type of battery better suited to this.
Please tell me lead acid is exactly what I need (only if it is of course!)

 

[stamfordian]

hi
sounds like you need to replace with ,duel purpose batteries ,these can be used for both aplications,modern batts are far more forgiving than batts of 5 years ago, cheers tb /forums/images/graemlins/laugh.gif /forums/images/graemlins/smirk.gif

 

[Elessar]

I've just got an S37 and the way the battery set up has been designed is poor.
The port engine batteries go through about 15ft of cable, maybe more, of inadequate cross section due to the way it's routed through the isolator switch. You don't need two batteries for the port engine just less resistance between the battery and the starter.
The s'board batteries do domestics and engine starting - again poor design.
I'm going to source a remote battery switch and route a battery for each engine through remote switches - then 3ft of cable should be plenty.
An ordinary, single, car battery will then be fine for each engine. I'll use deep cycles for the domestics only, they will only start the engines if both engine start batteries are for some reason flat.

 

[hlb]

Cant understand why, you presumably have 4 batteries to start the boat. Surely one is enough for both engines, after all it only has to start one. Then the other is bound to start.

 

[markdj]

Stay away from gel. If you want a battery for starting your engine then get a starting battery. If you want one for deep cycle then get a lead acid leisure battery. You will know the difference between the two as the leisure battery will be much heavier which means thick plates for deeper discharging. Starting batteries don't like being discharged to more than 5% but they give much high CCA due to thin plates.

Alternatively and if you have the money, the AGM batteries are the Rolls Royce but it's difficult to justify the initial outlay though they do last much longer.

 

[Sammo]

Lead acid IS exactly what you need…..
Check this out

Sterling Power




..............

 

[stamfordian]

hellow again just re re read where your boat s moored, there a good case if your leaving for winter to fit solar panals to tricle charge the batteries if you don,t have shore powr, i have two solar panals on my 26ft small boat which is plugged into shore power aswell but only uses 6 pounds of shore power elecric per winter mianly to power kettle and heating solar does rest and i am on broads/east coast
ps i use sealed lead acid deep cycle batteries...2 off on for start 6.2 gm 110amps and one for domestic 110amps, switchable does for small boat times up for larger loads/boat

 

[hlb]

Yep. 6 months is far to long to leave batteries uncharged, easy way to knacker them. Wonder about the rest of the boat. /forums/images/graemlins/confused.gif

 

[DavidJ]

Thanks guys, please keep the comments coming. I've got my eye on:
http://marinestore.co.uk/Merchant2/merch...trics-batteries
which seems to be boaty spec enough, the right terminal layout for me (reversed) and not overly expensive. What you think?

 

[DavidJ]

[ QUOTE ]
Lead acid IS exactly what you need…..
Check this out
Sterling Power
..............

[/ QUOTE ]
Certainly the best article I've ever read about batteries. Take a break for 5 mins and read it

 

[[2068]]

Interesting, but a bit black and white.

i.e. "all batteries are either starter batteries or fork lift truck batteries". Some leisure "deep cycle" batteries are somewhere in between.

Overall conclusion still stands, though. Lead Acid, then chuck em away when dead!

dv.

 

[Elessar]

Still think you should spend you money on the wiring.

2 of these electric battery switches fitted adjacent to the batteries will allow you to cut out yards of cable from both battery banks.

Then use 2 of these to keep all batteries charged and allowing any combination of bridging between banks in an emergency.

That's what I will do anyway!

 

[bazobeleza]

brilliant article, I re-equiped Beleza with a starter bank of 3x 90AHr bosch black cab starter batteries (6 litre lump that needs a bit of a kick) and my main domestic bank with 4 x 120Ahr bosch starter batteries all from costco several years ago and I paid a grand total of £50 apiece for them, gone up a bit since but still good value.

I use about 5 litres of distilled water a year topping up the banks.

 

[DavidJ]

[ QUOTE ]
Still think you should spend you money on the wiring.


[/ QUOTE ]
I think you're right. One of the problems with the current wiring is that the port engines only get charge from the port engine, not from the shore support.
Also your explanation of excessive wire would explain the reason why it has to have two 110Ah batteries for what is only a 3.6 litre engine.
Thanks for that.
Just as an aside, never switch the batteries off when the shore support is on. I've just done this and blown the ammeter shunt module unit just behind the ammeter....next job!!

 

[DavidJ]

[ QUOTE ]
.......all from costco several years ago and I paid a grand total of £50 apiece for them,

[/ QUOTE ]
I'm actually going to Costco this week and hadn't considered them for batteries....you might have just saved me a few quid...thanks!

 

[Elessar]

Wonder if that's a fault - the charger on mine has three outputs, currently wired as port, starboard (with domestics currently) and bow thruster.

 

[DavidJ]

[ QUOTE ]
Wonder if that's a fault - the charger on mine has three outputs, currently wired as port, starboard (with domestics currently) and bow thruster.

[/ QUOTE ]
Now that's interesting, I'll check when I'm next there in three weeks. You've obviously gone into a lot of investigation of your boats electrics.

 

[msimms]

Replaced all of ours (three) with these last year and 14 months later still fine. Got them from www.tayna.co.uk. Think there was a small discount having three delivered rather than three times the cost of a single delivery. Might be worth a phone call.

 

[DavidJ]

Thanks Mark, Tanya look very good