charging via cigarette lighter

[fjweaver]

I have 2 batteries (one in the engine compartment, the other in the cockpit locker) in series & can either or both be switched on or both off

I'd like to leave my Accumate charger on when leaving the boat. There is an adaptor to charge thru the cigarette lighter.

Can I leave both batteries 'on' and charge both using the cigarette ligther adaptor?

 

[VicS]

[ QUOTE ]
have 2 batteries (one in the engine compartment, the other in the cockpit locker) in series & can either or both be switched on or both off


[/ QUOTE ] In parallel i guess you mean.

Personally i would not leave the batteries ON.

Cigarette lighter sockets generally are piss poor and often make bad or unreliable contact (Perfect for what they were designed for but nothing else ) and my phone charger shorted the whole darned shooting match out in one car!) Having said that there are plugs and sockets available that do positively lock together.

I would make a separate and fused provision to connect the charger directly to the engine start battery. If however you want to have both batteries on charge then you should be looking for a charger with 2 independent outputs

EDIT: Sorry that reads a bit on the "sharp" side. It was not intended to

 

[fjweaver]

no worries that's fine Vic and yes I did mean in parallel.

Was worried about the cigarette lighter charging but would have been a quicker way of doing it with no rewiring - will investigate further. only a stop gap as i'm looking to put in an all in one consumer unit & charger at the end of the year

 

[Searush]

FWIW, I too would be nervous of leaving batteries connected or charging via a ciggy lighter. However, I recently got a cheapo solar panel that sticks on a window & connects to one battery by croc clips. I dithered about this for a while, then decided the output was too low to cause a fire or any other problem & left it connected. It has been a great success giving my starter battery a steady trickle to keep it in good condition. I may now get a seperate one to top up the domestics battery as well.

 

[VicS]

[ QUOTE ]
i'm looking to put in an all in one consumer unit & charger at the end of the year

[/ QUOTE ] One of the Dolphin ones? Expensive but a very convenient way of installing a basic shorepower unit and battery charger. Even the smallest has dual charging outputs.

Even as stop gap I would steer clear of the ordinary cigarette lighter type of connector. Nothing holds the plug in fully except for the pressure of negative connection on the side of the socket

 

[rogerdog]

[ QUOTE ]
However, I recently got a cheapo solar panel that sticks on a window & connects to one battery by croc clips. I dithered about this for a while, then decided the output was too low to cause a fire or any other problem & left it connected

[/ QUOTE ]

Yes they do work well -but you should ensure that the wires for the panel connected to the battery are fused - the solar panel won't produce enough to cause a problem but the battery that you are now connected to can!

 

[William_H]

A better trick is to fit 2 diodes to the positive lead from the solar to the 2 battery positives. Cathode (head of the arrow or the ned with a band) goes to the positive battery terminal. If you fit the diodes near to the battery terminals you don't need a fuse. The diode will stop current flowing from battery to any short circuit.
This arrangement will charge both batteries equally while enabling you to leave battery power turned off. Diodes need be only small silicon types. (a few pence from an electronics shop).
The added volt drop of the diodes doesn't matter with solar producing some 20volts no load. olewil

 

[moody1]

[ QUOTE ]
[ QUOTE ]
have 2 batteries (one in the engine compartment, the other in the cockpit locker) in series & can either or both be switched on or both off


[/ QUOTE ]
I would make a separate and fused provision to connect the charger directly to the engine start battery. If however you want to have both batteries on charge then you should be looking for a charger with 2 independent outputs

[/ QUOTE ]

A previous forumite mentioned a split charge unit available from Maplins for less than a tenner. It uses a standard charger (not a fancy drop to maintenance charge type or chip controlled, it has to be a basic unit). Connected to each battery it splits the charge to the battery that needs it. Simple and effective as well as cheap. He also reccomended the use of a mechanical timer to switch the charger on and off for a number of hours so many days etc. We followed his advice and have a beautifully maintained set of batterys on board with little cash outlay to sort.
Maplin Reference : http://www.maplin.co.uk/module.aspx?moduleno=37767&C=SO&U=OldModulePage

 

[bedouin]

[ QUOTE ]
FWIW, I too would be nervous of leaving batteries connected or charging via a ciggy lighter. However, I recently got a cheapo solar panel that sticks on a window & connects to one battery by croc clips. I dithered about this for a while, then decided the output was too low to cause a fire or any other problem & left it connected.

[/ QUOTE ]
If you are taking this route then I would make sure you have a fuse in the circuit somewhere near the battery.

While the solar panel does not put out enough power to cause problems, if a short developed in the panel itself or the lead it would short out the battery itself, and that has plenty of power to cause a fire!

 

[DaveNTL]

THESE charge via a cigarette lighter socket or croc clips and have an optional charge controller to prevent overcharging which is recommended for the larger panels.

They have coupling cables for two or more panels. I have two and the controller which I use at anchor. Still considering whether to keep them running when the boat is left unattended.

Available from West Marine in the USA, not sure if they are in the UK yet.

Apparently VW are going to be using this firms panels as a standard feature in their cars.

 

[VicS]

The issue over using cigarette lighter style sockets is not so much one of safety as one of reliability. You might plug your solar charger in and come back 2 weeks later and find that at some point during that time the connection as been lost.

The fuse issue is unrelated to the sockets. Any equipment added to the 12V system should have a fuse fitted as close to the connection as possible, or ever better be made to a fused connection. The fuse should be rated to protect the added cable from the potentially very high current that could flow from the battery in the event of a short circuit occurring.

Therefore provided you have a fuse rated below the max rating of the wiring to the solar panel and its controller the system will be safe to leave connected but you should not be upset if you find the connection has failed at the plug and socket.

 

[DaveNTL]

[ QUOTE ]
The fuse issue is unrelated to the sockets. Any equipment added to the 12V system should have a fuse fitted as close to the connection as possible, or ever better be made to a fused connection. The fuse should be rated to protect the added cable from the potentially very high current that could flow from the battery in the event of a short circuit occurring.

[/ QUOTE ]

So the charge controller which has an 'Auto-reset circuit breaker for reverse polarity and surge protection' doesn't do that?

 

[VicS]

The controller is primarily a regulator to prevent overcharging the batteries. It has built in protection against the consequences of reversed polarity connection and against surges . What might cause surges I don't know!
It is possible that the reverse polarity protection may protect against the consequences of a short circuit occurring between panel and controller, but insufficient information is provided to know one way or the other. Even if it does a fuse is still necessary to protect the wiring between battery and controller.

Looking around that website I notice there are some quite large panels and controllers able to control up to 25A. While reluctantly accepting cigarette lighter style sockets for small panels there is no way I would consider them for large panels or multiple panel arrays. A poor contact on a plug carrying several amps would be a fire hazard.

 

[VicMallows]

[ QUOTE ]


Cigarette lighter sockets generally are piss poor

[/ QUOTE ]

It seems to be an inescapable fact-of-life that nearly all plug/sockets which become endemic in consumer electronics fall into that category.

Just think: Belling-Lee coax (standard TV antenna) ; RCA Phono ; SCART ; mini Jack Sockets ..................

And we all continue to use them because it's the easiest/cheapest option!

(and by the way, LIDL have from today 3-way lighter adapter leads at £3.99. At least they have a slightly better than average plug on them /forums/images/graemlins/smirk.gif

Vic