Dual battery & on-board compressor install, Discovery Sport

[Scott_Parkes]

Greetings to All,
A few months ago we made a trip with my MY17 Disco Sport to the Flinders Ranges. The car coped with everything thrown at it (although we were not too adventurous!), but storage space was an issue. This got me thinking as to how I could install a dual battery system and on-board compressor. What follows is for a 5 seater, with factory cargo divider.

It turns out to be very easy. If the styrofoam surrounds around the spare wheel are all removed, this frees up a great deal of space around the spare wheel; and between the wheel, cargo barrier and rear seats. Two Optima yellow tops fit in between the rear seats and the spare wheel. The can be secured using a tie down strap running from a small hole in the outer seat runner to the inner bolt securing the two lateral braces that are under the original styrofoam surround. The existing inner bolts can be replaced by an M8 eye bolt to facilitate this. The batteries are connected in parallel, and charged from a Redarc DC-DC convertor.

The ARB twin compressor can be mounted low on the cargo barrier, with M6 vibration isolators and oversize washers. The 4L air tank fits in the recess on the R between the spare wheel and the wheel arch. I had longer stainless braided air hoses made at a pneumatic tool supplies, and mounted the air outlet and the switch to the side of the cargo barrier. The switch wires need to be cut, extended and joined. The compressor is wired with an Anderson plug directly to the new dual battery set-up.

With all this, there is about 5 cm of rear seat travel lost. The resulting space between the cargo barrier and the rear seat back can be utilised with bags that attach to the barrier (3 of the MSA small bags fit across the barrier). There is additional space around the spare for a bottle jack and other tools. The air hoses and inflator for the compressor are stored in the MSA bag above it.

With the false floor back on, only a small amount of space is taken up by the compressor, the rest if the install is hidden. A 28L Waeco fridge fits nicely in front of the compressor, and I am having some custom drawers made to fit along side (600 x 550 footprint). An important consideration is access to the spare; therefore the drawers and fridge are secured with tie-downs and not bolted in.

I hope this is useful and happy to provide further info. I hope the pictures tell the story (but on uploading some of them are upside-down, sorry!).

Regards to All

Scott

[weeds]

Nice....just be careful with the heat coming off the compressor.

[TB]

Impressive!

[drivesafe]

Hi Scott, that’s an interesting location for the auxiliary batteries.


I bought a new VW Tiguan in December last year and with no room under the bonnet, I found a similar solution for mounting the auxiliary battery in the rear cargo area.


While I only removed enough of the styrofoam to allow the battery to fit, leaving the bulk of the rest of the foam in place for the sound dampening.


With removing all the styrofoam from your wheel well, have you noticed any change in the sound levels?

[Scott_Parkes]

Hi,
No, good thought. But no, I haven't noticed any change. I did have to remove just a little of the foam under the carpet behind the back seats, to allow the batteries to sit level, but again, no change in the sound/nise.
Best,
Scott

[drivesafe]

Thanks again Scott and BTW,

:welcome:

[velocity08]

thanks for sharing :)

I’m quiet hesitant to pull things apart in the car and have decided to go with an external Ryobi compressor for $90 from Bunnings which works off the same batteries as all the plus one tools.

Will be looking at a goal zero yetti rechargeable battery via a removable solar cell as a secondary backup, it can also be hooked up to the car battery as a booster with an adaptor.

It’s probably a more costly option but saves me hacking into the car as I’m more likely to butcher it beyond reasonable repair - lol

[velocity08]

Scott how did you find the car on your trek do you have any other
Mods?

Just curious as I’ve only done a
Small amount of off roading and the car so far has exceeded my expectations with everything stock from factory.

Will be looking at some Grabber AT tyres next.

“”Cheers
G

[Scott_Parkes]

Scott how did you find the car on your trek do you have any other
Mods?

Just curious as I’ve only done a
Small amount of off roading and the car so far has exceeded my expectations with everything stock from factory.

Will be looking at some Grabber AT tyres next.

“”Cheers
G
Hi,
Thanks for your reply. So my only other modifications have been AT tyres and a tyre pressure monitoring system. Like you; I have found it very capable off road; with the major limitation being my driving talent!
Cheers,
Scott

[velocity08]

Hi,
Thanks for your reply. So my only other modifications have been AT tyres and a tyre pressure monitoring system. Like you; I have found it very capable off road; with the major limitation being my driving talent!
Cheers,
Scott

Have you completed the complementary one day landrover-experience course?

I’ve heard it’s meant to be quiet good, I’m currently waiting for more dates to be released.

“”Cheers
G

[Nico Verhelst]

Hi Scott,

very nice setup ! I am also looking to install a battery "under the floor ", and connect it via a DC-DC converter to the starter battery, in order to use the energy from the alternator to load this auxiliary battery. I am curious how did you do the routing of the cable from the starter battery to the battery in the rear ? Where is the cable going ?

Regards,
Nico

[drivesafe]

:welcome: aboard Nico.

Can I make a suggestion, if you are not in a hurry to have a dual battery system fitted, it may pay you to wait and get some advice on whether a DC/DC setup will be good for your vehicle.

At this time, none of the DC/DC suppliers know how to setup a system in vehicles with STOP/START and there could be some serious implications for your starting battery caused by using a DC/DC devices in these vehicles.

Just a suggestion.

[Scott_Parkes]

Hi Scott,

very nice setup ! I am also looking to install a battery "under the floor ", and connect it via a DC-DC converter to the starter battery, in order to use the energy from the alternator to load this auxiliary battery. I am curious how did you do the routing of the cable from the starter battery to the battery in the rear ? Where is the cable going ?

Regards,
Nico
Hi Nico,
So after many fruitless hours trying to find a grommet or hole in the firewall, I decided to cheat and use the rear fusebox in the cargo area instead. If you remove the cover; you will find blank slots with no fuse and a single terminal. In the middle and top of the grey segment there is a high current terminal with constant 12 Volt. The easiest way of tapping into this is to use a dual fuse tap (Jaycar part number SF5115, and for a mini fuse part number SF5125). I was a bit nervous that the current draw may be too high, but it is <25 Amp at peak (with a Redarc DC-DC convertor), and there is no excess heat in any of the wiring.

The tap for the switched 12 Volt can be found by probing with a multimeter in the blue section of the fusebox, the attached photo shows the point. Note that the power remains for about a minute after the engine is shut off.

The return negative/earth is all routed to the metal "U" section around the fusebox.

The whole setup has been stable driving daily for 6 months; with no error messages or other problems. The wiring and fusebox remains cool.134927134928134929134927134928134929

The attached photos demonstrate the fusebox taps, the voltmeter displays for starting and auxiliary batteries (while charging), and the completed setup with fridge and Drifta drawers. Please PM me if you want to go through things further.
Best,
Scott

[drivesafe]

Hi Scott, did you by any chance see how thick the main supply cable is that supplies the rear fuse panel?

Also, do you know if the suspension compressor is mounted in the rear?

[Scott_Parkes]

Hi Scott, did you by any chance see how thick the main supply cable is that supplies the rear fuse panel?

Also, do you know if the suspension compressor is mounted in the rear?
Hi Nico,
The input cable to the fuse box is about 5 mm thick, and the fuse box has 40 amp fusible links, so there is plenty of capacity. The Discovery Sport does not have air suspension; so there is no compressor in the car.
Best, Scott

[BobD]

Hi Scott, did you by any chance see how thick the main supply cable is that supplies the rear fuse panel?

Also, do you know if the suspension compressor is mounted in the rear?

Only steel springs on Discovery Sport.

[drivesafe]

Yep, so far I have not had a chance to look at one in any detail yet.

And this is why I have not been able to put a kit together yet.

Thanks for the info Scott.

[Nico Verhelst]

Thanks a lot Scott for a very clear explanation !
I am happy to read that it seems to work very well. And that no extra cable routing is necessary.... I will check it on my car, maybe will PM you if I would have further questions.

Best regards
Nico

[drivesafe]

Hi Scott and a big thanks for all the great info you provided during our phone conversation on Saturday and in this thread.


You were saying you found a thick cable at the rear fuse panel but was not sure what actual size it was, and I was going to see if I could track down a wiring diagram for the Disco Sports.


Well I have got on to one just for the rear fuse panel and if the cable you located at the back of the fuse panel is YELLOW, then it is a 6mm2 cable and is rated at about 45 amps constant load and should be fine for your setup.


I have more details about the Sterling Battery to Battery charger we discussed, but I will cover it in the Verandah section, and it looks like I need another Guinea Pig to test this new DC/DC unit.


More details about a Guinea Pig are located at


https://www.aulro.com/afvb/l550-discovery-sport/253729-looking-discovery-sport-dbs-guinea-pigs.html

[Johni]

Hi Guys
I am about to take delivery of my Sport HSE and have found this thread very informative. As soon as I have the vehicle I will dig around in the fuse-box and find the live wires and attach a more robust fridge connector than the traditional 'cigarette lighter' connector.
Has anyone had any other experiences with the dual battery than what has been discussed here - I am reluctant to start chopping out the Styrofoam on a brand new rig.
Regards, John

[Johni]

Hi Nico,
So after many fruitless hours trying to find a grommet or hole in the firewall, I decided to cheat and use the rear fusebox in the cargo area instead. If you remove the cover; you will find blank slots with no fuse and a single terminal. In the middle and top of the grey segment there is a high current terminal with constant 12 Volt. The easiest way of tapping into this is to use a dual fuse tap (Jaycar part number SF5115, and for a mini fuse part number SF5125). I was a bit nervous that the current draw may be too high, but it is <25 Amp at peak (with a Redarc DC-DC convertor), and there is no excess heat in any of the wiring.

The tap for the switched 12 Volt can be found by probing with a multimeter in the blue section of the fusebox, the attached photo shows the point. Note that the power remains for about a minute after the engine is shut off.

The return negative/earth is all routed to the metal "U" section around the fusebox.

The whole setup has been stable driving daily for 6 months; with no error messages or other problems. The wiring and fusebox remains cool.134927134928134929134927134928134929

The attached photos demonstrate the fusebox taps, the voltmeter displays for starting and auxiliary batteries (while charging), and the completed setup with fridge and Drifta drawers. Please PM me if you want to go through things further.
Best,
Scott
Hi Scott
As I am busy with connecting up a 'live' 12V output from the fusebox in the cargo area, I discovered that it is the blue section of the fusebox that has the permanent 'live', and the grey section has the switched supply. Your article has them the other way around. I hope that I am correct?

[Scott_Parkes]

Just to post a revision here. The fuse tap I used for the main supply to the DC-DC convertor ran quite hot, so I have now taken the power from the main 12 constant input to the rear fusebox. This is the thick red wire alongside a lighter red wire with a blue stripe. Rather than cut and re-join the wire I removed 1.5 cm of insulation using the hot knife attachment of a soldering iron, wrapped the additional wire on the exposed segment, soldered and insulated with tape.

This has run cool since the modification, even when the auxiliary batteries are discharged.

Best
Scott144559

[Robbo DS HSE]

Hi Scott

I am new to the forum and was reading your installation with interest, having purchased a DS August last year.

I was wondering if the lithium batteries enclosed in the small space under the cargo area get hot while charging, and if you have arranged some ventilation to the area.

Regards

Ian

[Scott_Parkes]

Hello Ian,
The batteries are in fact Optima Yellow to AGM, each 50 AH. They run quite cool. When the trim and styrofoam padding around the spare wheel are removed, there is enough space for some air circulation, and there is a gap between the wheel well and the rear carpet, so there is some air exchange between the wheel well and the interior.
Best
S

[Robbo DS HSE]

Thanks Scott

I have run a 16mm2 cable from a VSR at the start battery to an insulated stud on the side of the spare wheel well, then a short 2x6mm2 lead to the stud and an body earth with Anderson plug on the other end for the fridge.

I was thinking of including some batteries to keep the fridge going when the motor is off, and liked your idea of using space below the cargo area

Thanks again

[Scott_Parkes]

Hello Ian,
Thanks. Did you run your cable from the engine to the insulated stud underneath the chassis? If you have some pictures, I would be interested to see.
Best, Scott

[Robbo DS HSE]

I will take some pictures next weekend

[DiscoMick]

I don't know anything about Discovery Sports, so I was wondering if you actually need a DC-DC. Can't you just link the two batteries through a DBC with thick cable and fuses?

[drivesafe]

Hi Mick, the problem with the Discovery Sport, like with the Freelander, up to now, no one has found a reasonable and safe way to get thick cabling to the cargo area, where the auxiliary battery has to go.

In this case, a DC/DC device has been the best option to charge the auxiliary battery. This is because while the current limit of a DC/DC device will cause a much longer recharge time, but it is a simple and SAFE way to use the existing wiring.

[DiscoMick]

Interesting. Can't it go down the transmission tunnel or underneath and up again? I didn't realise. How does LR send power to the rear lights?

[Mamil]

Hi Mick, the problem with the Discovery Sport, like with the Freelander, up to now, no one has found a reasonable and safe way to get thick cabling to the cargo area, where the auxiliary battery has to go.

In this case, a DC/DC device has been the best option to charge the auxiliary battery. This is because while the current limit of a DC/DC device will cause a much longer recharge time, but it is a simple and SAFE way to use the existing wiring.

I've run two 16mm2 wires from the start battery to the rear of the vehicle through the existing wiring conduits. I would say it's both "reasonable" and "safe" but admit it is quite fiddly and takes some time as the wiring channels are not easy to access and already quite full. But, with a bit of perseverance and a few scraped knuckles I managed.

I went through the firewall at the existing grommet that takes the main wiring loom from the engine bay into the passenger compartment, those are my two new wires in the corrugated conduit...

148238

Past the wiring and fuse box behind the glovebox, where I located a new relay, activated in parallel with the existing trailer socket relay, so the new connection is only live when the engine is running...

148239

Along the wiring conduit under the front and rear passenger side door sills with the existing wiring. Getting round the B pillar was the trickiest part of the whole exercise…

148240

Up over the rear wheel arch...

148241


And through an existing wiring conduit into the boot and the rear junction box, and from there down to the spare wheel well...

148242

At that point mine goes through a grommet in the bottom of the spare wheel well to an Anderson plug on the tow bar, to charge the battery and run the fridge in my caravan, but it could just as easily feed a fridge or Aux battery inside the boot area, although my setup is only sized for a 50A current, and the maximum I draw in practice is 30A.

[drivesafe]

Hi Mamil and an excellent post.

That’s a brilliant bit of work!

One question, why did you say it is a 50 amp setup?

[Mamil]

One question, why did you say it is a 50 amp setup?

That's just what I specced it to, knowing that my max. current draw would be 32A, and with a bit of 'spare' for good measure! So I have a 50A fuse and 50A Anderson plugs, and then it was just a case of selecting appropriate cable that is rated to carry 50A and is large enough to keep voltage drop acceptable given the length of run to the caravan, but small enough for it to be manageable running it through the small spaces and tight bends. The only thing I deliberately oversized was a 200A relay hoping that would improve the life of the contacts considering it operates whenever the car is running.

[drivesafe]

Hi again Mamil, with that setup, you could easily charge a battery in the rear cargo area, and provide the 32 amps you want for your caravan and it would carry 60 to 70 amps for up to 30 minutes, without blowing the fuse.

If your Andson plugs are genuine Anderson plugs, then, with that size cable, they can safely handle up 90+ amps.

So I you need to supply more power to your van or cater for battery power in the rear cargo area, you are well and truely covered for any future expansion.

[Mamil]

Hi again Mamil, with that setup, you could easily charge a battery in the rear cargo area, and provide the 32 amps you want for your caravan and it would carry 60 to 70 amps for up to 30 minutes, without blowing the fuse.

If your Andson plugs are genuine Anderson plugs, then, with that size cable, they can safely handle up 90+ amps.

So I you need to supply more power to your van or cater for battery power in the rear cargo area, you are well and truely covered for any future expansion.

Thanks, that's good to know.

[Robbo DS HSE]

Hi Scott and Mamil

I ran a single 16mm2 SDI cable under the car, sited above the guards and brake hydraulic lines, then tied it to the brake line support brackets with a sleeve of pvc tube over the cable at each spot it is tied on for additional protection, then went through a unused grommet under the foam around the spare.

I terminated on a stud in the under the cargo area behind the foam around the spare tire, then connected at 2 x 6mm2 lead to it and an earth stud in the same area with a Anderson plug at the other end. As i don't have a van i curled it up beside the spare to bring out when the fridge is in the back. I didn't run a negative as although copper is a better conductor than steel the amount of CSA in the steel body seams to have limited resistance, so i connected the negative from the Anderson plug lead to a earth stud with a smear of conductive paste for good measure.

At the battery end i fed the 16mm2 to the area behind the battery where i made up an aluminium bracket holding a 50A DC circuit breaker and 140A VSR, then ran 6mm2 from the battery positive to the circuit breaker, then circuit breaker to VSR, with the 16mm2 fitted to the Aux side of the VSR. The negative from the VSR is terminated on the body earth lug behind the battery.

Photos below

148343
Battery compartment showing bracket holding CB and VSR

148344
VSR and back of CB

148345
Front of CB

148346
Cable run above brake lines and guards

148347
Cable coming through grommet under foam around spare tire

148348
Positive terminal post in space behind foam around spare tire, lead to Anderson plug terminated on positive post and body bolt adjacent

Only problem is the VSR cycles each time the motor stops in Eco mode, so when the fridge is on board i will have to remember to turn off the auto stop.

Future project is to add auxiliary battery in this area and a auxiliary power feed back to the console

Regards

Ian