What battery for my trailer sailer?

[mrming]

Out 23 foot trailer sailer came with a dodgy old car battery which has been okay but is now giving up the ghost. I want to try and replace it with the right battery for the job. There's charging from the Yahama F8 outboard which is only used to get on and off the mooring so is not much of a help. There's also a 30W solar panel.

The boat has cabin and nav lights (not yet LED but on the list to switch), VHF, wind, speed and depth instruments, and a DMK Box (wifi mux). There's also a couple of USB sockets for charging phones. We're pretty frugal with power, using a handheld VHF unless range is an issue and trying not to go crazy with lights in the evening.

We stay on the boat for a long weekend at the most. She's a competitive racer and so I don't want to add any more weight than strictly necessary.

What I'd like is to spec a battery that can last the weekend with the 30W solar panel topping up during the day, and not drop to a level that damages the battery.

Any pointers greatly appreciated .

 

[peteK]

Probably a 85amp hour leisure battery but I am sure others will say different.

 

[AngusMcDoon]

Varta Hobby 80Ah is a good one. Not the cheapest, but money well spent. Got mine from Tayna. I have 2 with a similar engine & 64 Watt of solar.

 

[VicS]

I get by with a 60Ah Varta leisure battery and a 5 watt solar panel

If I am lucky I get to spend a week on board once in a while other wise just occasional weekends.

Having a large enough solar panel, permanently mounted, is the key to ensure the battery is recharged as quickly as possible after the weekend

Estimate your power use over a weekend in Ah Make sure your battery capacity is at least double that. Size your solar panel to recharge it within a couple of days if possible but definitely before the next week end outing

But if you are trailer sailing is recharging with a mains powered charger during the week not possible

 

[mrming]

Varta Hobby 80Ah is a good one. Not the cheapest, but money well spent. Got mine from Tayna. I have 2 with a similar engine & 64 Watt of solar.

Seems that Varta Hobby is now Varta Professional (as far as I can work out). There's a 75AH on Tayna which would probably do the trick:

https://www.tayna.co.uk/LFD75-Varta-Professional-DC-Leisure-Battery-930075065-P3636.html

It weighs 18kg (eek) but I know the current lighter one has never really had enough capacity so I guess I'll just have to suck up the extra weight.

 

[William_H]

Well just for a way out alternative you could try 18650 lithium batteries with a charge controller for 3 cells which will also cut drain when batter voltage drops. These might be rated at 9900 maH But I doubt they are that good and will start at 12. 3 volts and finish at 10.5 volts.
You could afford several packs output in parallel or switched from one to another. So very light weight.
You might consider 4 cells and a 12v regulator with a 4 cell controller. All from China. Ebay. All chargeable from a solar panel no regulator. (that is in the cell controller) Of course you need to go to LED lights. olewill

 

[shaunksb]

I have a very similar set up on my Jag 24.

I use two golf cart batteries that fit into one standard battery box.

The Ritar RA12-45ev which is actually 50amps at the 20 hour rate.

They cost about £125 a pair but you can use and abuse them till the cows come home as long as you don't go below 10.5 volt.

So I have 100amps in one box but I can use pretty much all that if needs be.

My last 100amp "leisure" battery lasted a season and a half and cost about £85.00. I think it's worth paying the extra.


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[mrming]

I have a very similar set up on my Jag 24.

I use two golf cart batteries that fit into one standard battery box.

The Ritar RA12-45ev which is actually 50amps at the 20 hour rate.

They cost about £125 a pair but you can use and abuse them till the cows come home as long as you don't go below 10.5 volt.

So I have 100amps in one box but I can use pretty much all that if needs be.

My last 100amp "leisure" battery lasted a season and a half and cost about £85.00. I think it's worth paying the extra.


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That's very interesting thanks. I've ordered a 75AH leisure battery for now. If I have a similarly unsatisfying experience with that I may well give your setup a try.

 

[MonniotC]

Changing your interior lights to LED is probably the quickest, cheapest, and biggest hit you can make. And another solar panel to go with the one you've got. And a reasonable controller for the panels.

 

[ghostlymoron]

You need to match your usage, battery size and generation power. No good having huge batteries if you can only charge them on shore power.
I replaced interior light bulbs from 2x10w to 1xLED. Makes a huge difference.