Battery Charger Advice

seanfoster

seanfoster

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I've been trawling through the previous posts relating to battery charging, and I've got to say I'm getting confused!

My boat at present has a 110 ah battery, just being topped up by a 25w solar panel. I'm thinking about adding another battery (I think the solar panel would be ok to keep them both topped up on the basis of them self draining by 1% a day)
The boat will be on a swinging mooring, so a permanent electrical supply is a no-no.
What sort of (reasonably priced) charger should I go for if I want to give the batteries a boost everytime I visit a pontoon berth? Are there any non-marine (i.e non-ripoff) chargers that anyone has been using that provide good service?
 
Unless you are visiting the pontoon power for more than 24 hours at a time, you really need a decent 3 or 4 stage charger. If you keep it on the boat, then a marine one is more likely to survive the sea air.
 
OOOOHHHHHH .... be prepared to prise open that wallet and spend large amounts of wedge .....

Well that's what some will advise you to do.

There are a few doddery old so&so's like me that refuse to be convinced about "Marine" chargers and need ... (not liveaboard and no power hungry stuff on board).

So I use a cheap bog standard non-automatic charger - not intelligent, no maintenance charge facility .... Argos, Halfords, even dear Tesco have them. It then feeds a maplin splitter to charge both batterys as they want. It all stays permanently connected - so when I plug in to shore ... it starts automatically. If I'm on shore power for more than a day or so - I put a mechanical timer inbetween charger and mains so I don't overcharge.

I also at times use an "intelligent" charger - Halfords .... that drops to maintenance charge as soon as battery is charged. It can be left permanently connected if you want. But these automatic chargers don't like being connected to splitters or two batterys parelleled.

I have a boost charger that we use for the truck - this has manually set amps and can do 12 - 24V etc.

The bog standard job incl. Maplin spitter comes to about 25 quid all in.

The Halfords charger was just over 40 quid.

The truck charger was 65 quid.

Of course some may say you need multi-stage charger, high amp charge rates .... but if you are solar charging your batt's andf only need topping of alongside - IMHO don't waste money on fancy marine stuff. Non-automatic charger and connect to both batterys. Disconnect when finished.

Don't you have a charger at home for the car ?
 
That's the sort of info I was after, I only need power for instruments, nav and interior lights and a radio, and only for short trips anyway.
Do you know whatr model of splitter you have?
 
A cheap simple one, but remember that the actual output will be about half what they say, this is due to normally giving you a rms output not average. A 10 amp charger will only be good for 5 amp, so look for about a 20 amp one. This will give you 10 amp charge, so should top up the batteries in a few hours.

I would go for a voltmeter ( multimeter ok ), and monitor the recharge voltage, and switch off when you reach 14.6 /14.8 volt, depending on battery type. This will get rid of sulphation and keep the batteries good. Once the service batteries are up, you can always connect the charger to the engine battery.

You want a slowish charge, ie 20 hour rate, this will allow a resonable deap charge, a multi stage will give you little if anything, but will be a much larger hole in the pocket.
 
Halcyon, no doubt you know more about chargers than I do, I have been dealing with AC for 35+ years!

Surely the output is DC and hence is not effected by route mean square (rms) normally associated with AC? Can this affect the regulated output? /forums/images/graemlins/confused.gif

I am genuinly ineterested to learn why - dont wish to be contentious so if off-subject can you PM me....
 
I recently bought a charger from Halfords after the demise of my previous one which could only put out 11v. My local marine electrical man STRONGLY advised an automatic one which was what I bought. It is for use when laid up for winter and on occasional visits to Marina if needed. HOWEVER, it will not charge both my domestic batteries at the same time - I tried it and it never reached 'float' stage. So I would recommend that you read the spec before purchase relating to the max size of battery it will handle. I have 2 110Ah domestic batteries and 1 85Ah engine start. I have disconnected one of the domestic batteries temporarily and will reconnect at launch time.
 
Hello John on the older crude battery chargers the transformer feeds a rectifier then straight to the battery via an ampmeter. The actual current is either rectified half wave so DC actually a current (and voltage) rising from zero to peak then down again in a sine wave shape 50 pulses per second. If full wave rectification is used the same pulses are repeated in the time gap to give 100 pulses per second.

The ampmeter being mechanical relies on the inertia of the needle to show an average current. Which is what you need to know.

The average current depends on the battery voltage ie a which point the voltage rises of the pulse overcomes the battery voltage to push current in.
The pulse (open circuit) is usually quite high at its peak 18v or more and is often adjustable to adjust total current.)(The higher voltage falls with current flow to that of the battery due to internal resistance of the transformer)
The pulse shape means that while the average current will drop as the battery voltage rises it will not drop much compared to the rapid cut off of a smooth regulated DC.

Hence the crude battery charger will keep pumping current in as long as it is connected. Which means full charge is achieved quickly but means also the battery can be destroyed if left on charge inadvertently.

So for a guaranteed short charging period they are great. Just don't forget it is left on. olewill
 
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That's the sort of info I was after, I only need power for instruments, nav and interior lights and a radio, and only for short trips anyway.
Do you know whatr model of splitter you have?

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http://www.maplin.co.uk/Module.aspx?ModuleNo=37767&TabID=1&WorldID=&doy=6m1

But I believe they have a new one now ...

It's made by Kemo - very simple to wire in and mines been working for a few years now.
 
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I recently bought a charger from Halfords after the demise of my previous one which could only put out 11v. My local marine electrical man STRONGLY advised an automatic one which was what I bought. It is for use when laid up for winter and on occasional visits to Marina if needed. HOWEVER, it will not charge both my domestic batteries at the same time - I tried it and it never reached 'float' stage. So I would recommend that you read the spec before purchase relating to the max size of battery it will handle. I have 2 110Ah domestic batteries and 1 85Ah engine start. I have disconnected one of the domestic batteries temporarily and will reconnect at launch time.

[/ QUOTE ]

Go back to my post earlier and I mention that a Float charger doesn't go to float when batterys are parelleled - I don't know why but mine doesn't I know. It also will not work with relay or solid-state splitters - it will remain in charge mode.

Reason for my going back to bog standard non-auto charger
 
This might be a bit too dear for your taste, but I bought a Sterling 10amp switch mode charger for Kudu. It's brilliant.

Wall mounted, and fairly small, keeps the battery in order, always at full charge and has dual outputs, but mine is bridged for a single battery.

Here's a pic of it all in place...
http://onkudu.wordpress.com/2009/02/11/refitting-the-corribee-in-pictures/dscf0451/

As I say, you can go cheaper, but I wouldn't for the sake of an extra £40.
 
[ QUOTE ]
This might be a bit too dear for your taste, but I bought a Sterling 10amp switch mode charger for Kudu. It's brilliant.

Wall mounted, and fairly small, keeps the battery in order, always at full charge and has dual outputs, but mine is bridged for a single battery.

Here's a pic of it all in place...
http://onkudu.wordpress.com/2009/02/11/refitting-the-corribee-in-pictures/dscf0451/

As I say, you can go cheaper, but I wouldn't for the sake of an extra £40.

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For 40 quid - I can buy 2 chargers and have them totally separate. You say 10 Amp ... most cheapo chargers are 8A or so now ... not like old days of 4A etc.
 
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Go back to my post earlier and I mention that a Float charger doesn't go to float when batterys are parelleled - I don't know why but mine doesn't I know. It also will not work with relay or solid-state splitters - it will remain in charge mode.

[/ QUOTE ]

Does it still reach it's full voltage with two batteries, and does it go on to a higher voltage if left on?

Brian
 
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Go back to my post earlier and I mention that a Float charger doesn't go to float when batterys are parelleled - I don't know why but mine doesn't I know. It also will not work with relay or solid-state splitters - it will remain in charge mode.

[/ QUOTE ]

Does it still reach it's full voltage with two batteries, and does it go on to a higher voltage if left on?

Brian

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No idea - I didn't leave on long enough to risk. Batterys were already charged and when I connected auto-charger separately to each battery - it quickly dropped to maintenance charge. So I knew each battery was at that level. Connected both and it just stayed on normal charge rate. No drop to maintenance.

When I connected via the splitter - the charger failed to charge - I think the splitter confused the innards of the charger... it flicked on / off charge but not to maintenance.

Put my old charger back on that cost about a fiver and all fine.
 
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No idea - I didn't leave on long enough to risk. Batterys were already charged

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Could be then that the charger did not have enough power to get the voltage up to charge level, so no trip to float.

Brian
 
Can I be cheeky and add my own supplementary question..

I too am looking to install a battery charger to charge both my domestic and engine batteries. I have a pontoon berth and will possibly be connected to the mains for long periods of time.

From what I can see from the above posts, I'd need a charger that dropped to a float charge when the batteries were full, and I'd the charger would need two outputs to avoid using the splitter.. Is that correct?

If that's the course I take, then I presume I'm in to the 'open my wallet and let them take what's inside' scenario?

Cheers all.
 
[ QUOTE ]
Can I be cheeky and add my own supplementary question..

I too am looking to install a battery charger to charge both my domestic and engine batteries. I have a pontoon berth and will possibly be connected to the mains for long periods of time.

From what I can see from the above posts, I'd need a charger that dropped to a float charge when the batteries were full, and I'd the charger would need two outputs to avoid using the splitter.. Is that correct?

If that's the course I take, then I presume I'm in to the 'open my wallet and let them take what's inside' scenario?

Cheers all.

[/ QUOTE ]

Why ? Bog std charger without auto-float ... cheaper the better. Maplins splitter. Mains plug in timer.

So you set timer to be on for 1 - 2 hrs each day ... Charger then is controlled and not overcharging the batterys by being constant. Maplins splitter will decide which battery needs charge.
If you find batterys are not charged fully - increase the length of time on timer - but I suggest you have 1 day in the week cycle that is resting. Mine is 2 hrs per day 6 days a week ... 7th nothing. Charger is a 4A Halfords special from so long ago - I forget ... but probably 20yrs old.

Sorry but I am yet to be convinced by this marine stuff - it all seems to be based on 'stuffing as much amps in as fast as possible' which in my book is not so good.

I've just swapped out a normal wet acid battery that is yonks old for a larger truck battery to give me more A/Hr's ... That battery taken out is sitting in my barn still in VGC after hard work on board and above cahrging regime. The replacement battery was up to full next day after fitting.
 
Re above,

Thanks for the advice - think I'll go the cheap route as I'm convinced I'm being ripped off every time I buy something with the word 'marine' in front of it! Sometimes get paranoid about over-charging batteries, explosive fumes, etc which no doubt the industry are all to happy to perpetuate so it's good to hear that a basic set-up, if done properly, can work just as well.

If you ever come across a boat called Singing Blues - (assuming it's me(!)) I'll buy you a pint...
 
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