Deep Cycle Domestic Battery..

[onesea]

Which one and how much?

The battery is purely for domestics, it will run:
Nav Lights & Cabin Lights (presently filament but will change to LED before long),
Instruments GPS, Wind Gear & Depth
Maybe a tiller Pilot (ST2000)

The engine has its own starter battery the domestics are charged by a splitter relay? (Engine starter battery charges then domestics once voltage high enough), we have no shore power. I do leave a small solar trickle charger to top up when not onboard.

This means frequently the battery is not fully charged, if I am working on the boat I may use the radio and lights for several days and not start the engine... Some days the engine only gets 1/2 an hour use for 8 hours sailing.

My last boat had no battery charging onboard other than small solar panel and battery charger when on holiday, the battery lasted years like this. It was only for lighting and if the voltage dropped you knew as the lights went dim, I believe the instruments and autopilot will be more voltage sensitive.

As I see I have 2 options:
1) Grab an old battery form scrap at marina continue as was (this might work alternator harder?).
2) Buy a deep cycle battery.

I think no 2 is my preferred method but what cost, size and type?

As domestics I figure I want maximum amount of usable Amp Hours without damaging battery, at a reasonable cost.

 

[geem]

Fit a larger solar panel

 

[onesea]

Fit a larger solar panel

That helps replace my missing (old battery "borrowed" for another use, boat gets new battery ) battery by?

I do not want or need bigger Solar Panel, the question is what to replace missing battery with...

I like the electronic system on the boat:
It is simple, there is minimal to go wrong, I have all the charging requirements I need with no expensive and complicated regulators and battery monitors...
All I am looking for is recommendations for a decent deep cycle battery for the above use, or am I better digging out another old battery bin at the marina..

 

[JayBee]

You need a deep cycle battery with an amp hour (Ah) rating to suit your needs, after you have done the sums for the loads you intend to put on it!
You might also have some physical size restrictions. Have a look at the Battery Megastore - excellent service and "free" next day delivery.
http://www.batterymegastore.co.uk/

Type "dc" in the search box and there will be suitable and well priced choices with lots of info.

No connection etc..

 

[shaunksb]

All I am looking for is recommendations for a decent deep cycle battery for the above use, or am I better digging out another old battery bin at the marina..

It sounds like you work your batteries quite hard.


I've just gone down the route of pairing a couple of 50ah genuine deep cycle traction batteries (the ones for golf buggies/EV's)

The price of this type of battery seems to be coming down and I paid around £140.00 for 100ah compared with £70 - £90 for "ordinary" domestic batteries.

They (apparently) will do 300 cycles of 100% DOD though, so they will take some "hammer".

Depends how much money you want to throw at it now.



________________________________-

 

[aquaplane]

My useage on my Centaur is similar, I have a 100Amp hr leisure battery from the local caravan shop, £90 IIRC 4 years ago, it needs replacing though, I have left it undercharged too many times.

It may be a waste but £25 a year isn't much in the greater scheme of running a boat and I can't be arsed managing the battery to double the life for the sake of £25 a year.

 

[vyv_cox]

I find leisure batteries to be perfectly OK for this sort of duty, as Aquaplane says. Leisure ones are a bit of a compromise, being something of a 'Jack of all trades' in plate dimensions, but their main difference is that they are usually taller than starter batteries. The difference is made up of a space below the plates to allow sulphated debris that falls off the plates to accumulate without shorting out cells. For the rather hard life that you subject your batteries to, this is just what is wanted. Don't expect ten years out of it though, four years is a good estimate.

 

[Plevier]

My useage on my Centaur is similar, I have a 100Amp hr leisure battery from the local caravan shop, £90 IIRC 4 years ago, it needs replacing though, I have left it undercharged too many times.

It may be a waste but £25 a year isn't much in the greater scheme of running a boat and I can't be arsed managing the battery to double the life for the sake of £25 a year.

This may well be the best idea.
You are treating your battery so badly you are unlikely to get the benefit of a high quality one.
Spoil a cheap one instead.

 

[rivonia]

Because you are not giving the correct rate of charge at the correct time/intervals. Just get the very cheapest caravan type domestic battery that you can.

You'll do OK.

Good luck

Peter

 

[Tranona]

A deep cycle wet battery of between 100 and 130 AH capacity would suit. Somewhere between £120-150. I got mine from Shield Batteries but you can get similar from Batterymegastore as above. Actual capacity may depend on the amount of space you have as a 130 is a big heavy beast.

 

[onesea]

Replies so far are surprising me...

I have been considering going for Gel or AGM, I understood them to be more robust if left standing partially charged and being really deep cycled...

When I bought the boat she had 3 batteries. 2 Lead acid that appeared newer than a Gel Cel. The 2 lead acid batteries where knackered and the Gel still going strong, I was so impressed to me Gel was the way forward.

I removed the 3rd battery (not required) and on the advise of the local boat electrician this year I had been using a new 100amp starter battery (bought for boat) for the domestic and the Gelcel on the engine.

The 100amp starter battery is now in the Landy, as its battery died.

I believe my alternator is only little so cannot handle to big a battery say max 85 ish amp hour, the electrician scowled at the alternator trying to charge the big battery, never mind 3 batteries.

I guess 85 amp hour is enough to run an Autopilot for 12-24 hours (Raymarine ST2000 1.5amps?) and some lights for 24h giving around 48 hours on passage with no charging.

The odds of us doing 48 hours on the S Coast are slim, but a few days cruising with minimal engine use autopilot for some of the time and evening lighting below is quite likely. Then a night in a marina to charge and shower, or have to run the engine to charge the battery and put up with our own smells .

My thinking had been around £160 pounds for max budget, I was that impressed by the gelcel. So unless the forum advice comes out different I will be eyeing up the battery dump for a good looking leisure battery, if it is free and lasts a year it sounds better than £25 a year to me...

 

[aquaplane]

As I understand it, you need to have compatible batteries, all lead acid or all Gel, one type will steal all the charge and the other will die but I don't know which way round.

I was thinking of doubling up on the leisure/domestic battery(s) when I replace my tired one, but due to space I may fit 2x70 amp leisure batteries and easier to carry to the car to take home for a good charge now and then.

If I can sort out the alternator so that it charges every time not just when it feels like it, whichever battery(s) I fit will last longer.

 

[onesea]

As I understand it, you need to have compatible batteries, all lead acid or all Gel, one type will steal all the charge and the other will die but I don't know which way round.

I understand that when fitted in parallel, these are on 2 separate systems, engine starting and domestic only linked when they are being charged by the alternator.

 

[cmedsailor]

engine starting and domestic only linked when they are being charged by the alternator.

I think (not certain about this and would like somebody to confirm or reject) that when charging by the alternator via the splitter relay, they do get charged at the same time but current cannot run from the engine to the domestic battery or vice versa through the splitter. So, again they are completely separate.

 

[geem]

Sorry to be flippant earlier. No my best in the morning.
I have had my cheap as chips leisure batteries for 7 years now and they are still going strong. They cost me £45 each for 85 amp hour. We have 3 that make up the domestic bank. I run everything off them including starting the engine. We have another one for emergency should the bank go flat. it never has. We have a fridge and a power hungry autopilot but never use the engine to charge other than the normal motoring on and off mooring. My point was that cheap batteries are ok if you hook them up to solar. We have a couple of roving 40 watt panels that clip to guard wires. When you aren't onboard they charge your batteries so when you arrive at the boat you should be fully charged. Even if you leave the boat at the end of the weekend with discharged batteries they will be fully charged when you are back on board the following weekend.
This is far kinder on batteries than leaving them discharged most of the time.

 

[Pleiades]

For my type of sailing the "Leisure Maxpower Heavy Duty Boat/Caravan/Starting blah blah" batteries stocked (expensively of course ) in chandleries have been a total waste of money and effort. Never again will I sully my little ship with them. Good batteries will always be worth the hit on the wallet. Scrimp and save elsewhere on your kit list but not on batteries I say. Have a look at the above mentioned Haze batteries - I Haze electric vehicle/golf cart type deep cycling AGMs for my service bank - the bees knees! I have a solar panel, windmill, split charge controller etc - all that is just junk if the batteries themselves are not up to the job.

Robin
Pleiades of Birdham
MXWQ5

 

[Plevier]

For my type of sailing the "Leisure Maxpower Heavy Duty Boat/Caravan/Starting blah blah" batteries stocked (expensively of course ) in chandleries have been a total waste of money and effort. Never again will I sully my little ship with them. Good batteries will always be worth the hit on the wallet. Scrimp and save elsewhere on your kit list but not on batteries I say. Have a look at the above mentioned Haze batteries - I Haze electric vehicle/golf cart type deep cycling AGMs for my service bank - the bees knees! I have a solar panel, windmill, split charge controller etc - all that is just junk if the batteries themselves are not up to the job.

Robin
Pleiades of Birdham
MXWQ5

But the converse (corollary?) is true too - without a decent charging system (which you obviously have but the OP doesn't) you will junk decent batteries.

 

[Plevier]

Replies so far are surprising me...

I have been considering going for Gel or AGM, I understood them to be more robust if left standing partially charged and being really deep cycled...

###### In general, no, not as good. A few special ones e.g Lifeline are designed for cycling. No L/A battery likes being left part charged and with AGM/gel you cannot use such vigorous revival methods as with a wet one.

I removed the 3rd battery (not required) and on the advise of the local boat electrician this year I had been using a new 100amp starter battery (bought for boat) for the domestic and the Gelcel on the engine.


###### In general, gel batteries do not perform very well at high discharge rates so don't make very good starter batteries. Starter batteries are never good in cycling regimes. So by normal rules this advice was wrong both ways - but maybe he thought, as the cycling battery is going to get killed, use the cheap one.

I believe my alternator is only little so cannot handle to big a battery say max 85 ish amp hour, the electrician scowled at the alternator trying to charge the big battery, never mind 3 batteries.

######## Normal advice is to have at least 10A charge current per 100Ah capacity for wets or gel and at least 15%, some makes call for 20%, for AGM.

So unless the forum advice comes out different I will be eyeing up the battery dump for a good looking leisure battery, if it is free and lasts a year it sounds better than £25 a year to me...

##### Good luck. Do people really throw away batteries with a year's life left in them?

.

 

[rivonia]

Replies so far are surprising me...

I have been considering going for Gel or AGM, I understood them to be more robust if left standing partially charged and being really deep cycled...

When I bought the boat she had 3 batteries. 2 Lead acid that appeared newer than a Gel Cel. The 2 lead acid batteries where knackered and the Gel still going strong, I was so impressed to me Gel was the way forward.

I removed the 3rd battery (not required) and on the advise of the local boat electrician this year I had been using a new 100amp starter battery (bought for boat) for the domestic and the Gelcel on the engine.

The 100amp starter battery is now in the Landy, as its battery died.

I believe my alternator is only little so cannot handle to big a battery say max 85 ish amp hour, the electrician scowled at the alternator trying to charge the big battery, never mind 3 batteries.

I guess 85 amp hour is enough to run an Autopilot for 12-24 hours (Raymarine ST2000 1.5amps?) and some lights for 24h giving around 48 hours on passage with no charging.

The odds of us doing 48 hours on the S Coast are slim, but a few days cruising with minimal engine use autopilot for some of the time and evening lighting below is quite likely. Then a night in a marina to charge and shower, or have to run the engine to charge the battery and put up with our own smells .

My thinking had been around £160 pounds for max budget, I was that impressed by the gelcel. So unless the forum advice comes out different I will be eyeing up the battery dump for a good looking leisure battery, if it is free and lasts a year it sounds better than £25 a year to me...

Yup, your spot on!

 

[KellysEye]

>Deep Cycle Domestic Battery..

Trojan T105s are the best deep cyce batteries they are designed for golf carts. They are 6v so wire two in series, which we did. Available here http://www.alpha-batteries.co.uk/brands/trojan-batteries/t-105-trojan-deep-cycle-battery and many other places.