I have never suffered a flat battery including when the RRS was parked at the airport for 3 weeks last winter. However, with keyless entry, a BlackVue camera hardwired, frequent use of remote park heating and wife not always remembering to put the car in access mode when parking (inclined driveway causing suspension adjustments when engine off) ... I think it could be useful.

So, looking for advice on using a trickle charger to maintain the battery. I park on the driveway and don't have towing electrics so CTEK isn't an option. I guess a solar charger that connects to the power sockets won't work either because they are not live when car is off and locked. I came across this AA OBD port trickle charger. Is the OBD port always live? Has anyone used this or something similar and/or can comment on suitability?

TIA Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

OBD is possible but I would prefer somewhere else. You could use a piggyback fuse to something perm live or if you want to use the cigar socket you can make them perm live by removing the relay in the CJB and adding a jumper wire.

The permanent live for the tow electrics is in the rear left cubby if you want to add a Ctek comfort connector to it, given that you have no external electrics. Others use comfort connectors or even comfort panels to connect Cteks at the front of the vehicle.

Lots of choices, so pick the best for you.

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Thanks for the reply Robbie.

The fact that I don't know what a "CJB" is probably means I should steer clear of this option (although I managed to hardwire the dash cam and fitted & enabled remote park heating myself).

Good idea regarding tapping into the live tow electrics but then again wouldn't I need to run the CTEK power cord from the boot to inside the house or garage and the car would have to be left unlocked?

Any particular reasons for avoiding OBD? Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

Sorry, CJB is the central junction box, which is the big fuse box inside the car, rather than near the battery.

The fuse rating for the OBD is quite low, the wiring is quite fine and is surrounded by the CANBUS wiring. I'd just prefer not to use it for anything unusual.

You can close the boot on the Ctek cord, mains or 12v end. Those with exposed parking who are concerned with theft sometimes place the charger in the boot so only the mains wire is exposed, even if they have tow electrics fitted. You just need something that works for you.

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Thanks again. I will take a look at the wiring in the boot and also see what's the best place to run the cord to the mains. Reading all the good reviews here, CTEK would have been my first choice anyway if I didn't have the concerns I mentioned. Will also need to convince the Mrs. to disconnect it everytime. Worried she might forget and drive off, breaking the cable/charger  Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

Solar in England? Isn't that wishful thinking?  Gone - 2008 Stornoway Grey RRS 2.7 TDV6
Gone - 2009 Buckingham Blue RRS 2.7 TDV6
Gone - 2010 Alaska White RRS 5.0 V8 Aspirated
Gone - 2017 Chawton White RRS 5.0 V8 Supercharged
Current - 2010 Java Black RRS 5.0 V8 Aspirated
Current- 2024 RRS P400 SE Dynamic

It says it works in overcast conditions too and suitable for this country. Needs daylight, not necessarily bright sun. Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

AA site shows , 0,13 up to 0,2 amps per hour (I think, only when the sun is shining etc.) So it needs 10 hours to get 2 Amps !!, in the best case . I think, it`s not effective.

WolfgangK 2012 RRS SDV6, Pan European ST 1300
gone : Audi A6 Allroad, Toyota LC HJ 61,
Honda CB 750 Four

Agreed, seems like a waste of space in that case. I will explore if/how I can make a CTEK work for me while continuing to park on the convenient side of the driveway ( and away from neighbour's gunky tree ).

Last night was fairly cold and we finally got snow that settled ( for a few hours only though ) but the battery was in a decent condition in the morning. I know because my BlackVue is set to shut off if voltage drops below 12v but it was still up and recording. May be I don't need a charger to keep it topped up afterall. Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

Right ... couldn't stop thinking about it even though I was sort of convinced I didn't NEED it. Decided to buy a CTEK MXS 7.0 but then found MXS 10 for not a lot more on eBay. For some reason CTEK website says the comfort indicator cig plug is only for chargers up to 7A but the seller had advertised as 10A so went ahead and ordered that too. Stuff arrived on Saturday and indeed the cig plug box states 10A max so must be a mistake on CTEK website.

Didn't want to take the boot trim apart to tap into towing electrics live feed so went with "jumping the relay" option to make the rear sockets permanently live. Left the charger connected via the power socket in the boot overnight and in the morning it was showing the battery as fully charged. My Blackvue was still on so the voltage must have stayed above 12v all night

I liked the kit so wanted a more permanent set up (no extension wires and no cables going into the house) today. I fitted the comfort connector eyelet part to the battery, even though it is not convenient for me to charge with bonnet open but doesn't hurt. More importantly, took a power feed from the electric car charging point that I got installed outside the garage a few years ago (although I've never owned an electric vehicle). Bought a weatherproof mains socket to fit close to where I like to park the car. Glad I hadn't thrown away the cable trunking leftover from a DIY project a few months ago. Made use of it to avoid upsetting the Mrs. and it made sense too, all cabling being external. Last but not the least, left a note on the driving seat so that she doesn't forget and just drive away without disconnecting the charger first. Need to leave it in the car for a while until it becomes a habit. Constantly reminding her may not be enough

Now I can maintain the battery during the winter months while continuing to park on the preferred side of my driveway. Thanks for all the advice, especially Robbie  Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

Glad you got a combination that works for you. It is usually possible to lay the comfort connector so that it is held below the windscreen by the bonnet seal. You can also get creative with comfort panels in the front grill. This is a Ctek comfort panel in the D4 side vent:



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