Jump to content

another charger question

emlclcy

By emlclcy
in Boat Equipment

 Share

Featured Posts

WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted

 

 

I wonder why not turn the 'donor' car engine OFF then disconnect the jump leads...

It's not the donor car electronics that you're trying to protect, it's the one with the flat battery. Remember that many modern cars do not have regulators built into the alternator, it's all done by the cpu. Now imagine what happens when you disconnect the donor car and the flat one suddenly sees a much reduced voltage. The cpu has much potential (sorry) for getting terribly confused.

Link to comment
Share on other sites
nicknorman Veteran II

nicknormanDonate to Canal World

Posted
Posted

Paralleling chargers isn't going to cause a problem.

 

Just wondering about modem marine chargers, are they really still transformers, rectifiers and linear regulators? I can't imagine they are. Most probably SMPSs and so most of the ripple is filtered out before regulation, and the post regulation (high frequency) switching ripple is fairly easily removed without huge capacitors. It's only the basic car type chargers (unregulated and not "smart") that will have lots of ripple.

Link to comment
Share on other sites
emlclcy Community Regular

emlclcy

Posted
  • Author
Posted

There will be no load when charging. The solar will still be connected. I can give each battery say 1 hour then the other to gradually bring them up to fully charged.

They are just 2 x 250 ah batteries in series the load is an inverter I switch on and off. Just this time of year the panels don't do the business

Link to comment
Share on other sites
nicknorman Veteran II

nicknormanDonate to Canal World

Posted
Posted (edited)

So do we presume that the solar controller and the inverter are 24v, the charger is 12v?

 

If so there is no fundamental reason why you can't do as you suggest, provided the output from the charger is "floating". With the charger off and disconnected I'd check for resistance between the charger's 12v leads and the mains plug pins on its mains lead. If it is all very high resistance there should be no problem, but if say the 12v -ve lead was connected to earth, you'd have to be careful not to create a short when you connected this -ve lead to the mid-point battery connection. Whether it is a big problem will depend on what you are using to run the charger, ie mains, an integral genny, or a stand-alone (on the bank) genny.

Edited by nicknorman
Link to comment
Share on other sites
Graham.m Rising Star

Graham.m

Posted
Posted (edited)

There will be no load when charging. The solar will still be connected. I can give each battery say 1 hour then the other to gradually bring them up to fully charged.

They are just 2 x 250 ah batteries in series the load is an inverter I switch on and off. Just this time of year the panels don't do the business

 

Sorry is this 12V batteries wired in series to give 24Volts or what?

 

What voltage is the charger?

Edited by Graham.m
Link to comment
Share on other sites
emlclcy Community Regular

emlclcy

Posted
  • Author
Posted

Good call I understand what you are saying. Yes batteries 24 and charger 12. Will check if the charger has a floating output. My concern was if 1 battery was 100% charged and the other was say flat the charged battery would see the charge current for the flat one.

Unless this is not an issue

Link to comment
Share on other sites
Graham.m Rising Star

Graham.m

Posted
Posted

Good call I understand what you are saying. Yes batteries 24 and charger 12. Will check if the charger has a floating output. My concern was if 1 battery was 100% charged and the other was say flat the charged battery would see the charge current for the flat one.

Unless this is not an issue

 

Be very careful a lot of chargers do not have a floating output. If the neg is not floating do not even attempt

Link to comment
Share on other sites
Guest

Guest

Posted
Posted

Not only a misconception but also contrary to the advice for modem cars. It's very important to allow the 'poorly' battery to get some charge into it prior to disconnecting the jump leads. My own car's manual for example suggests to keep the leads connected for a minimum of 10 minutes.

 

This is to protect the on-board electronics.

Never knew that; we live and learn.

Link to comment
Share on other sites
WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted

Good call I understand what you are saying. Yes batteries 24 and charger 12. Will check if the charger has a floating output. My concern was if 1 battery was 100% charged and the other was say flat the charged battery would see the charge current for the flat one.

Unless this is not an issue

As long as the output is floating as described by Nick then no, it won't be a problem.

Link to comment
Share on other sites
emlclcy Community Regular

emlclcy

Posted
  • Author
Posted

mm I'm assuming earth and neutral are connected together at a star point. The source for the mains was from the existing or I should say original 12v victron inverter. The boat spent most of its life with a shore hookup. I insalled a separate 24v solar system but they share a common earth. The original system is 12v and alternator charged so I used this to run my victron 12v 15A charger for half hour on each battery. No big bangs so I guess the charger must be floating

Link to comment
Share on other sites
Graham.m Rising Star

Graham.m

Posted
Posted

mm I'm assuming earth and neutral are connected together at a star point. The source for the mains was from the existing or I should say original 12v victron inverter. The boat spent most of its life with a shore hookup. I insalled a separate 24v solar system but they share a common earth. The original system is 12v and alternator charged so I used this to run my victron 12v 15A charger for half hour on each battery. No big bangs so I guess the charger must be floating

 

Any reason why not to get a 24V Charger?

Link to comment
Share on other sites
WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted

... I used this to run my victron 12v 15A charger for half hour on each battery. No big bangs so I guess the charger must be floating

Ahh, so you're not asking 'can I do this?', you're asking 'I've been doing this, is it ok?'

 

Yes it is.

 

When you can afford a 24V charger that will of course be a better solution ?

 

Tony

Link to comment
Share on other sites
Graham.m Rising Star

Graham.m

Posted
Posted (edited)

Yes a 24v charger would be the answer but the question is, is it still ok to charge then independent assuming no grounding issues

 

It is very difficult to keep the batteries balanced doing it your way. Also you cannot give an overall equalisation

 

Short term possibly OK long term could be a problem

Edited by Graham.m
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.