My first boat - need help with battery charger info!

[neily]

Only been doing this for a month now so still gathering knowledge!

Got a Princess 32 with single diesel 75hp engine. Im not a great electrician and struggling with the relationship between battery, battery charger and shore power. I have purchased an alternator to battery charger thinking that was all I needed ie. whilst cruising batteries being permanently topped up, whilst in marina shore power does the rest. My confusion arises with why do I also need another battery charger to charge batteries whilst on shore power. OR should I not use the alternator to battery charger and just get a normal trickle charger?

If anyone can help me i would be delighted .......... thanks

 

[Guest]

Totally confused ....

You have purchased an alternator to battery charger ???? Pray can you explain a bit better - can you give a name and model ? As this does not make sense in my limited knowledge.

Your engine should already have an alternator fitted and be charging your batterys.
For charging from shore - you need a battery charger that gives good ampage when needed and reduces to float charge to maintain batterys once full charged.

Me - I have engine alternator when boat is in use. A standard car battery charger via Maplin splitter to both batterys when on shore power..... and I'm still using boat ... And a Halfords automatic float charger when I leave boat at home marina for long periods. This Halfords charger is left on the start battery as then I can always start the engine and domestic can be topped up charge from engine ... then when I reach next shore power swap chargers ... and use the spiltter.

I do not use boosters or fancy add-ons as above seems to work.

Still trying to figure out what you have bought .....

 

[Salty John]

Welcome to the forum.
In simplistic terms:
When your engine is running your alternator will charge the batteries. What you refer to as an "alternator to battery charger" is probably an alternator charge controller which controls the way your alternator charges the batteries: It improves the efficiency of the charging procedure, allowing high charging voltages to persist until the battery is approaching very nearly full charge and then dropping into a less agressive mode to preserve the batteries. Without this device the alternator voltage supply to the battery tails off progressively as the battery fills up and it takes much longer to charge the batteries.
A shore power charger takes 240v shore supply and charges your 12v batteries. It has nothing to do with the alternator or engine. It is useful for allowing you to charge your batteries without running your engine at the dock.
These are two separate methods of charging your batteries.
I suggest you get hold of a copy of Boatowner's Mechanical and Electrical Manual by Nigel Calder, or the considerably less expensive 12v Bible for Boats by Miner Brotherton.
Happy boating!

 

[Kawasaki]

Welcome aboard Neil32.
js48 has posted you a cracking reply.
Well done js ,that was clear and simple. (must av been simple cos I understood it!)
Anyway chaps what,s with this letters then/23/56/27/89 gig all about?
There are a few Forumites who use this format.
This time I have to ask why?
Nothing sinister,just a curious nosy sort of person!!! is what I am!
Anyway Welcome man with Name and number /forums/images/graemlins/cool.gif

 

[neily]

cheers js48 - you've been a great help.

You have cured a big headache for me - i've been trying to figure this out for myself for the last 2 weeks! Many technical explainations have been passed on to me but yours is the first i can actually understand. Cheers for the simplicity. I will get myself a shore power charger and the suggested bible!

cheers /forums/images/graemlins/smile.gif

 

[roly_voya]

When you say an alternator to battery charger is that actually what its called - eg is it a Sterling Alternator to Battery Charger. If so look up their web site and they will give advice by email on fitting it. If their are problems with the boats electrics I would definatly advise that you get a good marine electrition to do a survay and recomendations even if you then do any work yourself, otherwise you could either spend a lot more than you need and/or still finish with a system that dosnt work well