What type of battery charger do I need?

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shamrock

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www.tydewi.co.uk
One for the electrical experts out there.

Do I need a pukka £100 battery charger or something cheaper?

I have been keeping the batteries topped up by solar over the summer but now on shorepower and want to use a charger. We have a Link-2000 regulator already fitted, so does this do all the necessary control and let me fit a simple car type charger, or should I buy a proper Sterling or similar?

The skinflint approach is because we depart for Caribbean and then Canada next year so a 240-12v charger is useless after that and we already have a decent 110v one.

Batteries are 900AH Rolls Surrette

Other option is a 240-110v transformer to drive the existing charger.

Suggestions from the panel?

thanks. Nick
 
[ QUOTE ]
Batteries are 900AH Rolls Surrette

[/ QUOTE ] With batteries that big a cheapy from Screwfix or any where else for that matter will be no where like big enough. But was that a typo?
 
A cheapo charger will give you around 5A/120AH a day at constant current which is around the probable self-discarge rate of a 900AH bank (1%/day) so should be OK BUT if you have a "decent" (? 4-stage charger) then the 240/110 tranformer will be a better option as it will look after you premium (expensive ) batteries much better - you can sell it before you go don't forget!
 
Sounds like he means 90 amp hr 900 amp hr would need a boat of its own!

With batteries up to 110 amp hr (largest i ever had) i use a 20w solar panel without a regulator, that cycles the battery discharhing a bit at night and charging as the sun comes up.

If you use the battery as the main power source then add a 50/60 or 85w panel but then you will have to add a regulator or keep an eye on the charge at that can cook the battery if left!

When near power any battery charger will do but i bought a small pulse charger from lidle for 20 euros its about the size of 2 ciggarette packets and sealed and ideal for a compact boat such as mine to my total amazment it seems to charge better than the conventional charger!!!
 
With a battery bank of that size and quality I think I would favour using the system you already have, which is no doubt a quality charging and monitoring system, fed by a transformer from a builders merchants.

Cheap and effective, waterprrof enough for the marine environment, easy to move on when you no longer need it.
 
Transformer...

A transformer is by far the most cost-effective solution, and will enable you to use the existing smart charger to get the best out of your batteries.

Nice looking boat, by the way!
 
Re:Charging big battery bank

We have a 1050Ah house battery bank (not a typo) and to charge it we have a 4KVA diesel generator which has a maximum charging current of 280 amps, and a 2.5KVA inverter which also acts as a 4-stage shore power charger giving 120 amps. So we have 240v AC on tap all the time - and can even run our 12,000 BTU air/con heating system from the batteries - for up to 2.5 hours. This is not a "cheapo" option - but as liveaboards we like our home comforts and are prepared to pay for them. Its all realitive to the origoinal cost of the boat.
 
Thaks all for quick replies as usual, yep, think you've convinced me and I'll get a transformer - actually just did another search and found maplins doing a special on a 300VA transformer which should be big enough for the job and down to 20 quid, so that's now a no-brainer.

And no, not a typo, really 900AH and top of the range batteries - they are over 15 years old so I need to do a proper load check before we set off but the signs are that they are OK.
 
Not big enough!

A 300VA transformer isn't anywhere near big enough! If your charger can supply say 100A, you'd need at least 1200VA rating - or say 2000VA to allow for efficiency losses, etc. Go for something like the Screwfix one colmce suggested.
 
Re: Not big enough!

The charger is a West Marine 20A output at 12v = 240VA so I reckoned that'd be OK.

The boat is rarely connected to shorepower, we'll be on a swinging mooring from April - and we have 2x100W panels plus a wind gen, so this is really meant only as top-up charging over the winter. Will consider the screwfix transformer though, might know someone with a spare one.

thanks
 
Re: Surprised...

yes, but the boat has been liveaboard all her life, not sure she's ever been marina based.

there's a 65A and 120A alternator on the engine, plus the solar and wind.

If I was staying marina based I'd invest in a proper charger, but we're not, hence the question.

thanks

N
 
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