Any reason I can't trickle charge through the trailer socket?

[skotl]

We don't use our car much so, if it's had a series of starts and very short journeys, the battery often drains (modern car syndrome, where the car is never truly "off").

The dealer recommends leaving it on trickle charge but I don't want to be plugging in under the bonnet or in the boot (where the actual battery lives).

Any reason I couldn't connect a trickle charger to the trailer socket, which has a permanent 12V on pin 9? Electrically, that is going to end up at the same +ve post on the battery...

I was thinking of rigging up a quick release plug & socket to a trailer plug for the inevitable time when I forget it's connected and just drive off.

Thoughts?

 

[Bobtail4x4]

I have been thinking the same on a couple of my cars,
as long as the 4 terminal on the S socket is permanent live it will work,

 

[Ross365]

Got this problem too, but on one car I am using one of these battery isolation switches https://www.ebay.co.uk/itm/334971820021?hash=item4dfde057f5:g:-YkAAOSwL8ZkIuQq&amdata=enc:AQAIAAAA8MCrHrO9gXQ9T76ePvNQA8pE3dzZ84GWqLjrtalMKKkMei2i4XiOk66MHduZiF2dtfSbliCKjduJlnXNFFniQRmEfj0BHZ/D9l7225+QrF8rdkaG/NzLfCB058nz1lMjWAhpc6t6/mPjXgGeegsuNf9boI3T60BYLgNyATPwPhlm1n8GHxkG6QQUjcFafbNVw7VzcuMNBTHEeB+/uuY0ISOwt23z9mti6zsut+RheRFlZpSbmJVf1TPp8uQz8tdQCR+xhJee7o43LEDzlDsXtAONoomT+a1KxILF+lQEsk7awsfPjx1PBni9WzGaRdbUdw==|tkp:Bk9SR7jW7_q3Yg and it works very well indeed.

The only drawback is that some car radios lose the station memories when the battery is isolated.

 

[Pigeon_Droppings2]

In my Volvo XC70 the rear boot socket is hot (basically always live)....I kept a solar panel plugged in and stuck to the window which worked a treat.

Don't see any reason the trailer socket can't be used in the same way with a trickle charger.

The car was often left for months...I killed 1 battery by depleting the voltage so this was a solution to that problem.

 

[8ob]

Did something along these lines on a pickup truck with the 7n type plugs/sockets,it was more for charging the battery pack on the trailer but would work both ways. Put a two way switch in the boot on the fog light (blue wire ) and run a separate wire from this switch to the battery. Short lead then on a male trailer socket from the charger connecting fog and earth and this will charge the battery if the switch is in the correct position, flick it back for normal use.

Bob

 

[skotl]

OK - sounds like a plan. In terms of "quick release plug and socket" for when I drive off and forget it's plugged in, this seems like a reasonable option right?

I'd follow the opposite-the-norm approach and have the 12V supply on the plug pins and the socket connected to the car, so there was never any danger of someone plugging a 230V lead into the car! (over-thinking it, I know...)

 

[OJCar]

Ctek do an adaptor for their chargers to do just this.
(IMO expensive at £33.60)

https://www.mobilecentre.co.uk/ctek...harging-vehicle-battery-through-towing-socket

Positive to Pin 9 and Negative to Pin 13.

As regards the "Drive away protection" don't do up the twist lock (or remove it) length of para-cord attached to the plug and a suitable immovable object ?

 

[Mikey D]

Those orange connectors you pictured are quite hard to pull apart ,so u might break the charger wires first in a drive off situation

 

[Ross365]

mention of CTEK raises the question of what will you use for the trickle charger? People used to leave old fashioned transformer-based chargers running unattended for long periods. I'm not sure how long I would want to leave a modern (switched mode) charger running unattended; their reliability concerns me.

 

[hotponyshoes]

I'm not sure if those orange plugs are keyed?
Check one first as you'll do some damage if it gets plugged in reverse polarity.

Have you got a 3d printer?
I've seen a free stl for a quick release Power connector that just uses magnets to hold together.

 

[Morrisman]

Those orange connectors you pictured are quite hard to pull apart ,so u might break the charger wires first in a drive off situation

Make a big orange sign to hang on the steering wheel while it's connected up.

 

[MetalMonkey]

I'm not sure if those orange plugs are keyed?

It is a good point, they aren't!

Personally I wouldn't use any mains compatible plug on a vehicle, just in case something gets plugged in that shouldn't.

I'd be more inclined to look at something like this if you want something that will disconnect when pulled:

https://www.ebay.co.uk/itm/372591928903

or this

https://uk.rs-online.com/web/p/magnetic-connectors/1760897?gb=s

https://uk.rs-online.com/web/p/magnetic-connectors/1760896

 

[skotl]

It is a good point, they aren't!

Personally I wouldn't use any mains compatible plug on a vehicle, just in case something gets plugged in that shouldn't.

I'd be more inclined to look at something like this if you want something that will disconnect when pulled:

https://www.ebay.co.uk/itm/372591928903

or this

https://uk.rs-online.com/web/p/magnetic-connectors/1760897?gb=s

https://uk.rs-online.com/web/p/magnetic-connectors/1760896

Love that magnetic connector, but not at £59!

 

[skotl]

mention of CTEK raises the question of what will you use for the trickle charger? People used to leave old fashioned transformer-based chargers running unattended for long periods. I'm not sure how long I would want to leave a modern (switched mode) charger running unattended; their reliability concerns me.

...which was going to be my next question!

I'm looking at Noco chargers which have a good rep, and the dealer says that's what they use in the showrooms.

 

[skotl]

Hmmmm.... Bit of 3D printing and we might have a solution...

 

[OJCar]

^ That is almost cheaper than a ball of string ...

 

[gaz1]

why just lift your bonnet find a place for the charger run the wires to the battery and charge it up its what they do on the forecourts of car sales

if your bothered about the extension slide it under the car and just latch the bonnet back down

i cant see the point in messing around just to recharge the battery up most of the time i do the recharge when working near it

 

[Ross365]

...which was going to be my next question!

I'm looking at Noco chargers which have a good rep, and the dealer says that's what they use in the showrooms.

Noco look like modern, switched mode chargers and are appreciably cheaper than CTEK, which my mate (the electronics engineer) likes most.

I bought a very cheap switched mode charger last year; it lasted 3 months, then failed overnight, completely overcharging and destroying the battery.

In ~40 years, I've never had a transformer based charger fail.

 

[bricol]

Hmmmm.... Bit of 3D printing and we might have a solution...



View attachment 411033

Are you not fixing a problem you don't actually have? You need another trailer plug to connect to the socket on the car - so as others have suggested, don't fully secure it, or even relieve it a bit so it will come out easily if you forget.

 

[Pigeon_Droppings2]

why just lift your bonnet find a place for the charger run the wires to the battery and charge it up its what they do on the forecourts of car sales

Lot of cars have rear batteries buried under layer of boot floor stuff I think (Volvo!)....there is a main feed at the front but means opening the fuse compartment and leaving it open.

I used to leave a trickle charger on my mr2 with the bonnet down...worked really well until one day the battery exploded. I have zero idea why but I don't do it anymore.