Battery Charging

[daves6guitars]

I'm about to remove my engine for a recon, but will need to keep the batteries charged for occasional use of my electrics at weekends. I have a genny which has a 12v charging facility on it. Do I need to disconnect the boat electrics/battery management system whilst charging and to which terminals of my 4 bank set do I connect the charger, +ve on battery 1 and -ve on battery 4 or +ve and -ve on battery 1. 'Scuse my ignorance, I will get round to doing a 12v electrics course one day

[FORTUNATA]

It sounds a bit too obscure for people to fathom exactly what the layout is here. All you need to do really is connect a 12 volt charger to the battery bank and make sure it is indeed a 12 volt charger. Always check all the positive terminals are connected and all the nagtive terminals are also connected. It doesn't matter where each charger terminal is coupled (so long as the pole is correct) but normally it's the extreme end of each bank. So, if you have a line of four batteries, one + charger lead will do go + battery terminal no 1 and one - lead will go to battery no 4 - terminal. Or if that sounds confusing, just be sure negative goes to negative and positive to positive.

Battery chargers normally give out a little more than 14 volts to overcome internal plate resistances.

 

 

I'm about to remove my engine for a recon, but will need to keep the batteries charged for occasional use of my electrics at weekends. I have a genny which has a 12v charging facility on it. Do I need to disconnect the boat electrics/battery management system whilst charging and to which terminals of my 4 bank set do I connect the charger, +ve on battery 1 and -ve on battery 4 or +ve and -ve on battery 1. 'Scuse my ignorance, I will get round to doing a 12v electrics course one day

[daves6guitars]

It sounds a bit too obscure for people to fathom exactly what the layout is here. All you need to do really is connect a 12 volt charger to the battery bank and make sure it is indeed a 12 volt charger. Always check all the positive terminals are connected and all the nagtive terminals are also connected. It doesn't matter where each charger terminal is coupled (so long as the pole is correct) but normally it's the extreme end of each bank. So, if you have a line of four batteries, one + charger lead will do go + battery terminal no 1 and one - lead will go to battery no 4 - terminal. Or if that sounds confusing, just be sure negative goes to negative and positive to positive.

Battery chargers normally give out a little more than 14 volts to overcome internal plate resistances.

 

Thanks for that...perfectly understandable, just didn't want to do any damage to the battery management system by putting a higher voltage through it.

[GUMPY]

I'm about to remove my engine for a recon, but will need to keep the batteries charged for occasional use of my electrics at weekends. I have a genny which has a 12v charging facility on it. Do I need to disconnect the boat electrics/battery management system whilst charging and to which terminals of my 4 bank set do I connect the charger, +ve on battery 1 and -ve on battery 4 or +ve and -ve on battery 1. 'Scuse my ignorance, I will get round to doing a 12v electrics course one day

 

Any 230v genset with a 12v output will not charge your batteries from the 12v output

You need a mains charger and run it of the 230v.

[daves6guitars]

Any 230v genset with a 12v output will not charge your batteries from the 12v output

You need a mains charger and run it of the 230v.

 

Interesting...I haven't tried it yet my self, but I lent the genny to a chap who's batteries were flat and it charged them up fine!!

[GUMPY]

Interesting...I haven't tried it yet my self, but I lent the genny to a chap who's batteries were flat and it charged them up fine!!

I have assumed that its a 230v genset

If its just 12v then it will work

[daves6guitars]

I have assumed that its a 230v genset

If its just 12v then it will work

 

 

Well it appears to be both then, as we run power tools and various other 230v appliances off of it too. It has sockets for 230 and 12v.The manual states that the 12v is for charging batteries.

Edited September 3, 2010 by daves6guitars

[bottle]

Does the manual also say what amperage this 12v socket can supply.

 

I bet it is about 8amp maximum, to charge batteries you will need a lot more unless you are willing to run the generator for very long periods ( I mean hours and hours and hours)

 

I am with Idleness and would add that a three stage charger would be best, not a 'standard' car battery charger.

[FORTUNATA]

If you're into reading then I'd highly recommend John C Payne's book The Marine Electrical And Electronics Bible. I'm a big John C Payne fan as I learned so much from that book (originally aimed at sea going boat people). There is actually a chapter on just battery chargers. These usually have overload and short circuit protection. According to Payne, a Swedish company was doing really good "smart" chargers even back in the eighties. These cycle the charge voltage to overcome plate resistance. They're better than standard alternators because of the cycling of voltage levels.

Take a look on the web for 12 volt battery chargers. Or have a look at the one you currently own. You need to find out what the maximum voltage is. Some chargers go a little over 14 volts for periodic "blasts" to stir up the plates a little. Just be careful, though. Payne reckons some of the other 12 volt batteries (the non lead acid variety) have been known to explode when subjected to higher voltage charging.

I think this may be the more modern name of the company Payne raved about back in the eighties:

http://www.ctekchargers.co.uk

Well it appears to be both then, as we run power tools and various other 230v appliances off of it too. It has sockets for 230 and 12v.The manual states that the 12v is for charging batteries.