patmartino93 Posted June 10, 2020 Share Posted June 10, 2020 Hello everyone! I seek help and advice installing a leisure battery on my new VW Caddy Maxi! It's a 2015 model with blue motion technology, therefore smart alternator and brake-regen and all of that! I searched for battery chargers and recently bought a " Schaudt WA 121525" booster because it seemed well priced, had good reviews and was on a German website where I had already a full shopping cart (and therefore free shipping ;-) ). NOW, I'm pretty confident about the wiring, but I'm confused about the D+ connection : is it really necessary? And where can I source a wire to it? Diagrams suggest a connection to the alternator, but it looks really tricky to access.. I've seen a few tricks on the internet, like sourcing the D+ from a fuse box or glove box light.. Could this work? Is the D+ just an "ignition signal" and any 12v signal when the engine is running would do the job? Or.. Should I just ship back the unit and buy a Sterling or Votronic that seem a little more straight forward to install and apparently don't need a D+ signal? Thank you all for your help, and enjoy the camping summer!! Link to comment Share on other sites More sharing options...
arthur49 Posted June 10, 2020 Share Posted June 10, 2020 patmartino93 - 2020-06-10 2:11 PM Hello everyone! I seek help and advice installing a leisure battery on my new VW Caddy Maxi! It's a 2015 model with blue motion technology, therefore smart alternator and brake-regen and all of that! I searched for battery chargers and recently bought a " Schaudt WA 121525" booster because it seemed well priced, had good reviews and was on a German website where I had already a full shopping cart (and therefore free shipping ;-) ). NOW, I'm pretty confident about the wiring, but I'm confused about the D+ connection : is it really necessary? And where can I source a wire to it? Diagrams suggest a connection to the alternator, but it looks really tricky to access.. I've seen a few tricks on the internet, like sourcing the D+ from a fuse box or glove box light.. Could this work? Is the D+ just an "ignition signal" and any 12v signal when the engine is running would do the job? Or.. Should I just ship back the unit and buy a Sterling or Votronic that seem a little more straight forward to install and apparently don't need a D+ signal? Thank you all for your help, and enjoy the camping summer!! I have a smart alternator and regen braking on my Renault Master base vehicle. What I did was put the WA121525 in line from starter battery/alternator to the CBE Control unit. In this way it doesn't matter what the alternator volts are, the Schaudt unit produces a rock steady14.4v and the bonus was no need to disable existing split charge relay ...... from memory! The idea came from the late Allan Evans of AandN Caravan Services and it works a treat (I actually used the bigger WA121545). Sorry I haven't answered your D+ question but thought you might be interested in my solution Check out these links: https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Improvements-to-leisure-battery-charging/50677/91/ http://www.aandncaravanservices.co.uk/wiring-your-camper.php Link to comment Share on other sites More sharing options...
Alanb Posted June 10, 2020 Share Posted June 10, 2020 The term "leisure battery" is widely misused on this forum, and more generally in the UK. A leisure battery is a battery suitable for deep discharge at relatively low currents. I tend to use the term "habitation battery", but "service battery" is also a good alternative, and shorter. For your habitation/service battery, you may wish to consider a dual purpose battery, of which the Varta LFD95 is a popular example. This type of battery has the advantage of being capable of being able to supply high currents, as well as deep (50%) discharges without shortening its life. If one of your prospective uses is to supply a 3 way, or Automatic Energy Selection (AES) fridge, then since such fridges can draw in the region of 15A when running on 12V, a significant proportion of 25A nominal output of your Schaudt WA121525 could be consumed by the fridge. The D+ signal refers to the alternator field connection. Overloading this point can cause the alternator not to start generating (so called lazy alternator). As you are aware locating a suitable connection point for the D+ signal is difficult in modern vehicles. If you decide to use a D+ style of control, I suggest considering the following alternative derived from the popular CBE 300 and CBE 520 systems. These use an ignition switched supply, which they monitor internally to be over about 13.2V. (Alternator deemed to be charging.) A suitable module from Ebay, to perform the voltage monitoring role is available here. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted June 11, 2020 Share Posted June 11, 2020 Patrick Welcome to the Out&AboutLive forums. There is a good deal of on-line discussion relating to leisure-battery charging for VW T5/T6 Transporter-based campers that have a smart alternator https://tinyurl.com/ycvt34mr and it’s reasonable to assume that the electrical system of your 2015 Caddy parallels that of a recent Transporter. Personally (as it seems to be the KISS approach) if the Schaudt WA 121525 demands a D+ connection and meeting that requirement is problematical for your Caddy, instead I’d opt for a B2B product from another manufacturer like Votronic or Sterling. I notice that you've made the same enquiry on the Practical Caravan forum. Best of luck with that ;-) Link to comment Share on other sites More sharing options...
mikefitz Posted June 11, 2020 Share Posted June 11, 2020 The VW Caddy has a smart alternator and thus there is no 'conventional D+' terminal on the alternator, the regulator is controlled by the engine electronics. The suggested alternative B to B chargers from Sterling and Votronic would ideally use a D+ type signal. Due to the problems finding this on a modern vehicle with a smart alternator, both manufactures suggest using 'ignition on' as a controlling signal for the B to B. I see no problems in adopting a similar approach could be used for the Schaudt WA 121525, using 'ignition on' as a control. This can be easily sourced via a piggy back fuse holder on a suitable 'ignition live' fuse in the Caddy fuse box. The suggestion of using a system to detect high voltages is going to fail on a VW smart alternator system, as the alternator average charging voltage is low, below 13 volts, peaking to 15 volts or higher for short periods under breaking or overrun. Thus any voltage sensing charging system will perform poorly. Some of the information on the internet including the you tube videos, give unsafe advice, specifically in the areas of fusing and cable installation. Mike Link to comment Share on other sites More sharing options...
Alanb Posted June 11, 2020 Share Posted June 11, 2020 mikefitz - 2020-06-11 11:29 AM -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- The suggestion of using a system to detect high voltages is going to fail on a VW smart alternator system, as the alternator average charging voltage is low, below 13 volts, peaking to 15 volts or higher for short periods under breaking or overrun. Thus any voltage sensing charging system will perform poorly. Some of the information on the internet including the you tube videos, give unsafe advice, specifically in the areas of fusing and cable installation. Mike The above is fair comment on my suggestion. In view of Arthur49's experience with a smart alternator, the OP may wish to reconsider the output capability of the Schaudt WA 121525, particularly if used to supply a fridge. Alan Link to comment Share on other sites More sharing options...
Derek Uzzell Posted June 11, 2020 Share Posted June 11, 2020 It might be worth Patrick wading through on-line forum discussions relating to the WA121525 unit https://tinyurl.com/yar3okxc This company has converted the VW Caddy https://www.lovecampers.co.uk/small-camper-conversions-and-camper-cars/ and the specification is said to include a "Leisure Battery and power management system”. They might be prepared to advise Patrick on how they have dealt with the Caddy’s smart alternator/braking system. (Given how compact the Caddy is (even the Maxi variant) I would have thought that - if a fridge is to be installed - it will be a small compressor type.) Link to comment Share on other sites More sharing options...
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