Author Topic: MK3 Electrics/Wiring Advice for Trickle Charging  (Read 270 times)

SuperCNJ

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MK3 Electrics/Wiring Advice for Trickle Charging
« on: December 31, 2019, 06:19:29 PM »
Hi Guys,

I'm looking to install trickle charging point in the boot of our MK3 Sport due to the number of short journeys we do so that we can keep the battery topped up easily. It has to be in the rear of the car as it's much easier to reverse into our drive.

I've been using a CTEK MX5.0 charger every few weeks so my plan is to install a socket inside the boot. I think I know how to route the cables most of the way, but I can't seem to find an easy route through the firewall to connect to the battery.

There seems to be a grommet hole for some cables just behind the battery which seems ideal, but I can't seem to get to it from the inside of the car. When I drop the glove box, all I see if more plastic and metal bracings covering the area. I can't seem to get to the other side of the grommet hole. Does any one know if there is an easier way to route a small cable into the engine bay area without having to drill a hole?

Also, I have two options in terms of wiring the cable to the battery and I'd like an expert to advise which one is best please.

1. Route both the positive and negative cables from the charging socket in the boot and connect directly to the positive and negative terminals on the battery.

2. Route only the positive (red) cable all the way through the car and connect to the positive of the battery. Then find and connect to a suitable grounding point near to the charging socket in the boot. I prefer this option as I only need to route a single wire but not sure if this is recommended as the kit comes with the same length red and black cables for option 1 above.

Finally, does any one know if using such a long extension lead for a trickle charger is a problem? The wire from the battery to the boot will be about 3-4m, then there's a 2-3m extension to the CTEK charger, so it will be about 5-7m in total and I think CTEK use 18AWG wires in their kit.

culzean

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #1 on: December 31, 2019, 06:22:50 PM »
You can get extension leads for charger with SAE connectors, so why not leave charging point at front of car ( through the front grille ).  Don't forget to put a fuse in the positive lead - mount the fuse close to battery and if the lead shorts out anywhere the fuse will protect the cable and your car from going up in flames.  get one of these as it already has a fuse in positive lead and it fits onto the M6 terminal clamp bolts ( they are normally long enough to get the ring tag and another M6 nut on ) bearing in mind that if you car has stop start you need to connect negative lead either to body or not directly to the negative terminal as the electronic module on the negative battery lead needs to be in circuit.  Don't worry about length of cable as the currents involved are small and voltage drop should not be an issue..

https://www.amazon.co.uk/KUNCAN-Motorcycle-Extension-Disconnect-Connection/dp/B01N7CHYCF?ref_=ast_bbp_dp

This extension is 12foot but longer ones are available 

https://www.amazon.co.uk/gp/product/B01N7CEV00/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

https://www.amazon.com/dp/B01MZZGHNK/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B01MZZGHNK&pd_rd_w=LyWQK&pf_rd_p=45a72588-80f7-4414-9851-786f6c16d42b&pd_rd_wg=LEOIL&pf_rd_r=2SXA679Z9YB4CFF3W42H&pd_rd_r=ddcd37f6-9fdf-405b-85d7-d2f51ab17a11&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExRjJXNkNCNzVKOU4mZW5jcnlwdGVkSWQ9QTEwMzEzODFMRlRYRFM3RDM2NjUmZW5jcnlwdGVkQWRJZD1BMDU0NDI0NTNITDVKUFRQWTNYTEQmd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl
« Last Edit: December 31, 2019, 06:38:03 PM by culzean »
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

SuperCNJ

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #2 on: December 31, 2019, 06:33:47 PM »
You can get extension leads for charger with SAE connectors, so why not leave charging point at front of car ( through the front grille ). 

This is 12foot but longer ones are available 

https://www.amazon.co.uk/gp/product/B01N7CEV00/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Thanks, I've seen some people have the charge point in the grill but the trouble is, for us, it's a lot more convenient to have the charge point at the rear of the car as we need to reverse into our drive.

SuperCNJ

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #3 on: December 31, 2019, 06:35:43 PM »
This is the wiring grommet hole in the firewall I was referring to earlier.


SuperCNJ

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #4 on: December 31, 2019, 06:39:04 PM »

bobby boy

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #5 on: December 31, 2019, 06:43:06 PM »
Why not run a cable underneath the car?

SuperCNJ

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #6 on: December 31, 2019, 06:52:34 PM »
Why not run a cable underneath the car?

I don't know! :-[ I guess it just seems better to protect it from the elements?

zzaj

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #7 on: December 31, 2019, 07:49:35 PM »
I have a Ctek charger. When I purchased a Ctek charger extension cable, I am sure I read somewhere that a longer cable means that a charge will take longer.

In any event (and to avoid any potential loss of current)..........

I run a weather proof 240v extension cable out close to the car and plug the charger's 13 amp plug into that.

I still need the 12v extension cable between the charger and the car because the lead on the charger is a bit short. The 12v snap together Ctek connectors on the extension cable and charger look pretty weather proof.

You should have, supplied by Ctek, a short connecting cable which you can leave permanently on the battery terminals so everything just clips together. I think it is to help charging motor cycle batteries where access is difficult.

I am pretty sure Ctek do recommend not using two extension cables due to lost of charging ability.

SuperCNJ

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Re: MK3 Electrics/Wiring Advice for Trickle Charging
« Reply #8 on: January 13, 2020, 01:28:17 PM »
Just an update on this. I've managed to locate a really easy route through the firewall and have installed the socket in the boot in case any one else was attempting the same job. I'm thinking of fitting a switch next to the socket as well as I'd like the option to be able to turn off the socket when not in use. I know the LED only uses very little power but given the really short journeys we do, I want to conserve as much power as possible.

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