[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

@Farnorthsurfer did you set the Dc-dc to lithium mode for the TN100 battery?

Also have you got any more BM2 views showing more days?
Yes the unit is set to Lithium profile. Easy enough to do when it was powered up.
Yesterday was a flat line all day as it just sat on the drive.
Back to work today which is a 12 minute drive and shows up like this.
1586773584892.png
Really need to get the Solar fitted but there is a problem with my pop top that can’t be fixed until the lockdown ends and I am not going to bond it on until it’s fixed
 
Last edited by a moderator:
Yes the unit is set to Lithium profile. Easy enough to do when it was powered up.
Yesterday was a flat line all day as it just sat on the drive.
Back to work today which is a 12 minute drive and shows up like this.
View attachment 65892Really need to get the Solar fitted but there is a problem with my pop top that can’t be fixed until the lockdown ends and I am not going to bond it on until it’s fixed
have you had the solar panel tested just loose out of the floor yet? . . . . . . for testing?
 
have you had the solar panel tested just loose out of the floor yet? . . . . . . for testing?
No not yet, its still in the box, but it's a good idea to test it. I should be able to hook it up to the van easily enough as I have lots of connectors and the cable on the panel is much longer than it needs to be. The van cables are all installed and terminate at MC4 plug breaks at the rear. I will let you know how that goes but it probably won't be until next weekend.
 
So I have the Photonic Universe 160w Solar Panel connected and its working fine. At first I just propped it up in the box by the van and despite it being quite late in the evening the Renogy unit gave a solid red light on Solar input and a few minutes later switched to flashing red indicating that it has switched to charge the starter battery.
Unsuprising as the Service battery is pretty maxed out after being on mains charger and alternator without any real load since I installed it.
So I just put the Solar Panel in the back of the van on the Reimo seat parcel shelf. It gets a reasonably good view of the full windows. Wasn't expecting much from it in this position but apparently its happy enough and the Renogy light is on steady. This morning I ran the Planar heater in Ventilation mode for 4 hours straight only a slight 0.05v change to the battery. Although I might try this again this afternoon with the Solar switch off to see if it drops more.
Anyway thanks for prompting me to try out the panel @Dellmassive it's all good so far:thumbsup:
 
I am looking into fitting a Victron 500A smart shunt (Newly release with Bluetooth so no need for the round display, phone is the display) to the second battery in my car, what sort of range does your Victron 712 Bluetooth have?
I have two Chinese voltage only monitors but the range is a useless 2 meters, I can read the voltage of my Blackvue B124 LiPo camera battery from the house 14 meters away.
My T6 has two batteries from the factory and may add one to that too. But only IF the range is reasonable.
 
I managed to install a renogy DC to DC mppt charger on my T6 and for a while I left it without the ignition signal connected and I want to say that it works perfect. I checked every day while driving the VAN and every time after starting the engine it charges the Lithoum battery with no exceptions, while driving always charged the battery no matter if I'm cruising or driving in the city ( always got 37Amps charging from battery monitor).It is not charging if the engine is off or if the key is off. When I installed the battery it was 30% charged (150 LiFePo4 battery) now after couple of days the battery is 100% and not going down at all. Is it possible I don't have a smart alternator on my 2018 t6? Or is it something else? So far I'm happy how it behaves but at the same time I'm worried my blue motion system does not work. Any thoughts ? Thanks
 
If you have the battery manager on the starter battery negative terminal (little shunt with its own ecu which has its own address word 61 battery manager OR can just feed info to the gateway 19 and can give useful information in MVBs) you have a LIN bus alternator, Most if not all UK spec T6 will have one.
Is your starter battery an AGM or EFB/EFB +?
These batteries will charge from between 14.7 and 15V depending on the starter battery state of charge, temperature, driving conditions, DPF loading, they can even be discharged by the system to allow regenerative braking charge and the reason why you shouldn’t fit a standard lead acid battery on a stop start van as they will overcharge and gas as the non stop start van charges around 14.3V.
 
I am looking into fitting a Victron 500A smart shunt (Newly release with Bluetooth so no need for the round display, phone is the display) to the second battery in my car, what sort of range does your Victron 712 Bluetooth have?
I have two Chinese voltage only monitors but the range is a useless 2 meters, I can read the voltage of my Blackvue B124 LiPo camera battery from the house 14 meters away.
My T6 has two batteries from the factory and may add one to that too. But only IF the range is reasonable.
The range depends on where you fit the unit and whats around it...

The BMV712 Bluetooth module is in the display so can have better range.

The only real way is to fit it and test it.

in my experience the range is IN the van or a few meters near the van.

The BM2 in the engine bay gets more range.

dont fit a power shunt to the starter battery as it already has an OEM one. (just stick with a voltage monitor)

Smart shunt on the second battery will be fine.
 
Hi, thanks for the reply.
The 2.5 meter range is no good to me if that’s what you are getting with your unit. Hopefully someone will produce something to allow REMOTE monitoring from the house 15 meters away via Wi-fi and or Bluetooth. (I use an always on hotspot to allow 24/7 camera monitoring hence the need to keep an eye on the secondary battery state).
I was just after user feedback with people who own Victron products with Bluetooth.
I retrofitted a second battery using genuine parts to the boot of my car, this can be done for Skoda Superb/VW Passat as the V6 petrol versions have their batteries in the boot due to space.

573D6211-5CB8-410E-AB36-94F90D3FBA60.jpeg

FC3A7015-F8F1-4593-950D-FDF547332955.jpeg

4D4240F5-E909-4D2D-A9FD-2679182157A9.png

8678B571-0868-481D-86BE-C385E983C97E.png

84D0134F-55CE-4E4A-B235-BB2BD27B1EF1.png

5326E0DA-93F5-4546-A077-C01ABC93B62F.jpeg

E371D003-F617-42C4-A4B1-ADC9FFE60FD5.png

5257BE87-BD41-445E-9741-FDC4CF596442.png

D825E394-2E87-43A8-AD52-91F3D0E09985.png

45EC3C05-2A7F-43A3-8299-6901CCD763C6.jpeg

540A5372-02A4-46AB-B5A7-2348DD732597.jpeg
 
Hopefully someone will produce something to allow REMOTE monitoring from the house 15 meters away via Wi-fi and or Bluetooth. (I use an always on hotspot to allow 24/7 camera monitoring hence the need to keep an eye on the secondary battery state).


you can do all of that with the Victron Kit and the "VRM portal". (Victron kit + RaspberyPi(VenusOS) + wifi hotspot (or Victron GX GSM)

have a look here: https://www.victronenergy.com/blog/2020/04/06/victronconnect-v5-20-connect-configure-remotely/


and here: https://www.t6forum.com/threads/battery-monitoring-how-i-done-it.15346/

and here: https://www.t6forum.com/threads/solar-sheds-other-non-t6-solar-projects-how-we-done-it.16457/
 
@Farnorthsurfer were you able to find the BCM or IGN feed from under the passenger seat? my van is also prepped for tow and I'm about to embark on fitting a DC-DC charger for my campervan setup.
 
That’s the sort of product info I need, it will save me lots of money buying and trying different product options, great write up by the author.
 
@Farnorthsurfer were you able to find the BCM or IGN feed from under the passenger seat? my van is also prepped for tow and I'm about to embark on fitting a DC-DC charger for my campervan setup.
No I didn't take any feeds from the VW wiring under the seat. After advice from @travelvolts and others I went with a simple piggyback fuse holder in the centre row of fuses as it works fine. I also ran an independant 16mm cable from the vehicle battery to feed the Renogy. Two reasons, the Renogy can take up to 50A charge which the big cable can handle and my fuse by the vehicle battery is much easier to get to then the big VW fuses under the vehicle battery. The thread I linked does tell you how to get the signal from the BCM buts it's a right pain and not worth the effort. Especially as you risk other things going wrong when and if you mess about with the BCM.

I did mess about a lot with the wiring under the passenger seat and got rid of a lot of the extra wire and fuse holders that were not used in my van. There was a five or six way fuse holder with one fuse in it so I depinned it and put the fuse in the other holder. Tidied up the big red wire feed to make it a lot shorter and remade the looms so that the DC-DC, Battery and Fusebox all fit under the seat. Just visible to the left of the camper fusebox is the VW fuse holder and relay.
1587557051412.png
 
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DC-DC related info . . .

just checked on the Renogy DC-DC (has an ignition feed)

same thing is happening here.

The starter is on EHU Victron 12v/15A charger, which is charging the starter battery.

The Renogy DC-DC is seeing the raised starter voltage and indicating the ALTERNATOR is running (even with IGN OFF)

The Renogy has started charging the Leisure battery.


Seems this is a feature of most modern DC-DC chargers . . . that even when they have the IGN/BCM RUN feed connected and switch off. They will startup when the starter battery voltage is high enough.


So with either EHU charger OR a solar charger connected to the tarter battery, both can be charged via the DC-DC


NO EHU, battery Low.

20200503_114514.jpg



.

And ALT shown as OFF.

20200503_114629.jpg




Then EHU connected to starter . . .

20200503_115457.jpg




DC-DC now shows ALT power . . .

20200503_114710.jpg



..

Victron shows 8A going to starter.

20200503_114556.jpg




starter shows voltage increase. . . .


Screenshot_20200503-115435_Battery Monitor.jpg



BMV shows 3.2A going to AUX battery via DC-DC . . .

Screenshot_20200503-115341.jpg




and AUX battery shows a voltage increase.

Screenshot_20200503-115321_Battery Monitor.jpg





Happy dayz . . . .


*******************************************************************************


Edit:

here is the 24hr BM2 BM3 readouts showing the effect of the EHU connected to the starter battery . . . . . . which is inturn charging the AUX battery via the DC-DC "Auto VSR mode"


we started off as above, with a 100% charged battery. so after 24hrs is i switched off the EHU (Victron 12v/15A bluesmart charger)

20200504_143103.jpg

20200504_143100.jpg


this is the Starter battery readout :

Screenshot_20200504-143053_Battery Monitor.jpg

and the BM2 24hr readout:

you can see the Bulk, absorb and float/storage stage in the readings. . . . .

Screenshot_20200504-143021_Battery Monitor.jpgScreenshot_20200504-143040_Battery Monitor.jpg

at 10am the folowing day when switched off you can see the drop back to the static battery volasteg.



Next up was the AUX battery . . . .

Screenshot_20200504-143153_Battery Monitor.jpg


here is the AUX 24hr readout.

This had NO EHU connected , , , , just the DC-DC,

again you can see the Bulk,Abs,Float stages in effect. . . . . untill about 2am when the DC-DC stops charging.


Screenshot_20200504-143143_Battery Monitor.jpg
.

.Screenshot_20200504-143136_Battery Monitor.jpg


next up is the combined data on the BM3 app.


Screenshot_20200504-143318_Multi-Batt Mon.jpg

.

Screenshot_20200504-143340_Multi-Batt Mon.jpg


Screenshot_20200504-143328_Multi-Batt Mon.jpg


test procedure:

EHU connected to starter battery at 11:30am day one.
EHU disconected at 10AM daytwo.

Current DC-DC charger : Renogy DC50mppt. (no solar connected)

This shows that as many other DC-DC chargers they work as a "Auto VSR" and will Auto-start when the starter battery is raised high enough.


1588599993622.png


*******************************************************************
 
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***************************************************************
EDIT: this has been added to the first post........ i need help filling in the blanks for other DC-DC units

I've started an excel sheet detailing the most important details of the various DC-DC charger units as an easy to read chart.

I've attached the sheet below to download, if you have any of the missing DC-DC chargers or want to add your own . . .

download the chart edit/add in your own unit then email it back to me for uploading: dellmassive@gmail.com

1588588956964.png



******************
 
Last edited by a moderator:
Additional BM2 & BM3 data added to above post (using EHU to charge Aux via DC-DC)
 
DC-DC Charger Test/Review . . .

REDARC BCDC1250D Sn-00035 =]

( first in UK when i got it from @travelvolts )
( i got the Victron Orion 12/12/30 from there too)
( Electrics | Travelvolts )



This time we have the Redarc BCDC1250D, now I've already got a BCDC1240LV and love it to bits . . .

in fact it might be my favorite DC-DC charger yet, due to its small compact size, rugged design and simplicity.

So why change ? (Redarc> Orion> Renogy> Redarc)

well this one is 50A where as the old one was 40A and this new one is the "D" version meaning it can take Solar input too. Oh and it can do Lifepo4 Lithium now as well =]

so better all round.

The design is the same with a slight change to the front panel LED arrangement.


1588605855445.png

..

Screenshot_20200504-155915_Office.jpg

*****************************************************************************************

Heres what the Redarc has to say about it:

The REDARC BCDC1250D In-vehicle Battery Charger is a 12V 50A In-vehicle DC to DC battery charger. It is the latest variant of the award-winning BCDC Dual range and features REDARC’s Smart Start technology.

Styled with a red line running down its back tells you there’s something different about this dual battery charger. A 50-amp charging output makes it the most powerful in REDARC’s BCDC range.

The BCDC1250D has been developed to provide a higher current output, it features an additional charging stage known as SoftStart which has been engineered to handle more demanding applications.

Featuring a Maximum Power Point Tracking (MPPT) solar regulator, the BCDC1250D will charge from both solar and the alternator simultaneously. And, with built-in 'Green Power Priority' it will select solar charging first, meaning less load on the alternator.

Suitable for 12 or 24-volt vehicle systems, the unit will also work with either standard or variable/smart alternators.

It is compatible with all common types of batteries used in automotive and recreational vehicles such as AGM, Gel, standard lead acid, Calcium and LiFeP04.

As a guide, the BCDC1250D is used for battery bank sizes over 200AH. For smaller batteries of 75-200AH REDARC recommends the BCDC1225D.



Proven and Tested

The award-winning technology in the BCDC has been independently verified and tested to ensure battery life is maximised, charging your battery to a proven 100%.

Built in Australia and tested for our unique conditions, the DC to DC battery charger will work in the extreme heat of the Simpson Desert, up to 80°C and can handle deep water crossings at Cape York – water, dust and vibration are no match for this charger.

If you’re heading out into the bush and want to get there and back again safely – you can trust REDARC.



Features
  • 50amp output makes it the most powerful in REDARC's BCDC range
  • Separate DC and solar charging inputs
  • Maximises the performance and life of your auxiliary battery
  • Simultaneous DC and solar charging with Green Power Priority
  • Suits 12V/24V standard and variable voltage/smart alternators
  • Suitable for AGM, GEL, standard lead acid, calcium and LiFeP04 batteries

*****************************************************************




*******************************************************************



*******************************************************************

here is the standard setup for AGM . . . . . .

1588606019013.png

And here is the Lithium setp:

1588606044467.png

and specs . . .

1588606090751.png



*****************************************************************************

So lets see it in action . . .

I "again" have fitted 50A Anderson connectors so i can easily swap these units in & out.

I've fitted a blue bullet connector for the IGN/BCM RUN . . . . and thats it - just plug and play.

i haven't connected any solar in this example. (i prefer a separate solar controller)

you can see how small it is compared to other dc-dc units, which is great if you are short on space.



20200504_155540.jpg

... the Anderson plugs are labled. . .


20200504_155527.jpg

you can see it tucks away niceley in front of the AUX battery . . .

20200504_155459.jpg

the front panel readout is slightly different . . .


20200504_155509.jpg

and the rear has a handy wire chart . . . . .

20200504_155547.jpg

.
The first test was, standard engine running . . . . which gave us a nice 14.6v (upto 50A) and a Bulk,Abs,Float charge . .

Screenshot_20200504-155453_Battery Monitor.jpg

the charge profile look like this . . .



Screenshot_20200504-155931_Office.jpg

.

1588688033608.png
.


Next up was the "Auto VSR" mode, where by the starter battery was connected to a EHU (Victron 12v/15A charger)

You canb see that same as other DC-DC chargers the Redarc started chargeing the AUX battery even though the igniotion was OFF. - which is nice.


20200504_161610.jpg

here you can see when the EHU was switch on . . . then off.

Screenshot_20200504-155702_Battery Monitor.jpg



Now i know it has a MPPT solar input, but im not sure yet if the Solar will reverse charge the starter battery as well as the AUX battery. (ill upodate this when i find out, untill then well assume it does not)

You can run upto four of these units in parellel.

The box comes with a couple of crimp/solder ends and bits,

The install guide calls for fitting MIDI fuses (60A) and holders . . . The unit its self is basically water proof and as such comes with 9" wire loom.

So you have to crimp/solder you own cables/midi fuses/rings on yourself. . . . . but that no problem.

shown over here: Dc-dc Charger (for Leisure Battery) -- How I Done It --

and here : Dc-dc Charger (for Leisure Battery) -- How I Done It --


.



Edit:

Auto VSR test with Victron EHU 12v/15A charger . .

The redarc kicks in then it sees the starter battery voltage rise, due to the victron charger.

so same as the other dc-dc units, the EHU charger on the starter battery will charge both the battery's.

for the test below the charger was connected at 8am and disconnected at 3pm. . . . .



this is the BM2 readout for the starter battery.

#
Screenshot_20200505-153134_Battery Monitor.jpg

you can see the 3 stages boost, abs, float from the victron charger.

Screenshot_20200505-153142_Battery Monitor.jpg

this is the BM2 readout for the AUX battery.



#
Screenshot_20200505-153225_Battery Monitor.jpg

here you can see an initial boost stage . . . then 13.2v float stage. (battery was charged already)

Screenshot_20200505-153218_Battery Monitor.jpg


this is the combined BM3 readout.

Screenshot_20200505-153523_Multi-Batt Mon.jpg
......

*******************************

edit: 1/6/20

email to Redarc Technical:

what is the max MPPT solar input spec/range for the unit on the yellow wire?
Isee that the VOC Max range is 9v-32v which is great.
but whats the max amps that can be drawn.?
If the unit is 750W, is it (w=v*a or 750w/32v=23A or 770w/22v=34A)
So basically what is the MAX I can go up to with solar arrays in series or parallel.
Can I use 4x 100W in parallel . . . . . (4x100w, 4x22v voc 4x6A isc) so 400W, 22v voc, 24A isc?
If I parallel up say 800W of panels bellow the 32v input max, what amps will be drawn?


Many thanks
**************
Reply:

The BCDC1250D (or any of the BCDC “D” range) do not have a limit as to how much solar can be CONNECTED to the BCDC. The limiting factor is how much it can draw from the solar panels. The BCDC’s can have as much solar wired into them as you like (below32v) without harming the product, but will only draw what they are able to produce at the other end. In the case of the BCDC1250D, 750w is the technical maximum amount that can be utilised fully, but 750w of solar panels rarely, if ever, produce 750w.
So long story short: Put as much as you like, not much point going over about 800-850w for the BCDC1250D.
Feel free to reply with any questions.


Best regards

*****************

 
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DC-DC Charger Test/Review . . .

REDARC BCDC1250D Sn-00035 =]

( first in UK when i got it from @travelvolts )
( i got the Victron Orion 12/12/30 from there too)
( Electrics | Travelvolts )



This time we have the Redarc BCDC1250D, now I've already got a BCDC1240LV and love it to bits . . .

in fact it might be my favorite DC-DC charger yet, due to its small compact size, rugged design and simplicity.

So why change ? (Redarc> Orion> Renogy> Redarc)

well this one is 50A where as the old one was 40A and this new one is the "D" version meaning it can take Solar input too. Oh and it can do Lifepo4 Lithium now as well =]

so better all round.

The design is the same with a slight change to the front panel LED arrangement.


View attachment 68520

..

View attachment 68534

*****************************************************************************************

Heres what the Redarc has to say about it:

The REDARC BCDC1250D In-vehicle Battery Charger is a 12V 50A In-vehicle DC to DC battery charger. It is the latest variant of the award-winning BCDC Dual range and features REDARC’s Smart Start technology.

Styled with a red line running down its back tells you there’s something different about this dual battery charger. A 50-amp charging output makes it the most powerful in REDARC’s BCDC range.

The BCDC1250D has been developed to provide a higher current output, it features an additional charging stage known as SoftStart which has been engineered to handle more demanding applications.

Featuring a Maximum Power Point Tracking (MPPT) solar regulator, the BCDC1250D will charge from both solar and the alternator simultaneously. And, with built-in 'Green Power Priority' it will select solar charging first, meaning less load on the alternator.

Suitable for 12 or 24-volt vehicle systems, the unit will also work with either standard or variable/smart alternators.

It is compatible with all common types of batteries used in automotive and recreational vehicles such as AGM, Gel, standard lead acid, Calcium and LiFeP04.

As a guide, the BCDC1250D is used for battery bank sizes over 200AH. For smaller batteries of 75-200AH REDARC recommends the BCDC1225D.



Proven and Tested

The award-winning technology in the BCDC has been independently verified and tested to ensure battery life is maximised, charging your battery to a proven 100%.

Built in Australia and tested for our unique conditions, the DC to DC battery charger will work in the extreme heat of the Simpson Desert, up to 80°C and can handle deep water crossings at Cape York – water, dust and vibration are no match for this charger.

If you’re heading out into the bush and want to get there and back again safely – you can trust REDARC.



Features
  • 50amp output makes it the most powerful in REDARC's BCDC range
  • Separate DC and solar charging inputs
  • Maximises the performance and life of your auxiliary battery
  • Simultaneous DC and solar charging with Green Power Priority
  • Suits 12V/24V standard and variable voltage/smart alternators
  • Suitable for AGM, GEL, standard lead acid, calcium and LiFeP04 batteries

*****************************************************************




*******************************************************************



*******************************************************************

here is the standard setup for AGM . . . . . .

View attachment 68521

And here is the Lithium setp:

View attachment 68522

and specs . . .

View attachment 68523



*****************************************************************************

So lets see it in action . . .

I "again" have fitted 50A Anderson connectors so i can easily swap these units in & out.

I've fitted a blue bullet connector for the IGN/BCM RUN . . . . and thats it - just plug and play.

i haven't connected any solar in this example. (i prefer a separate solar controller)

you can see how small it is compared to other dc-dc units, which is great if you are short on space.



View attachment 68524

... the Anderson plugs are labled. . .


View attachment 68525

you can see it tucks away niceley in front of the AUX battery . . .

View attachment 68526

the front panel readout is slightly different . . .


View attachment 68527

and the rear has a handy wire chart . . . . .

View attachment 68528

.
The first test was, standard engine running . . . . which gave us a nice 14.6v (upto 50A) and a Bulk,Abs,Float charge . .

View attachment 68530

the charge profile look like this . . .



View attachment 68531

.


Next up was the "Auto VSR" mode, where by the starter battery was connected to a EHU (Victron 12v/15A charger)

You canb see that same as other DC-DC chargers the Redarc started chargeing the AUX battery even though the igniotion was OFF. - which is nice.


View attachment 68532

here you can see when the EHU was switch on . . . then off.

View attachment 68533



Now i know it has a MPPT solar input, but im not sure yet if the Solar will reverse charge the starter battery as well as the AUX battery. (ill upodate this when i find out, untill then well assume it does not)

You can run upto four of these units in parellel.

The box comes with a couple of crimp/solder ends and bits,

The install guide calls for fitting MIDI fuses (60A) and holders . . . The unit its self is basically water proof and as such comes with 9" wire loom.

So you have to crimp/solder you own cables/midi fuses/rings on yourself. . . . . but that no problem.

shown over here: Dc-dc Charger (for Leisure Battery) -- How I Done It --

and here : Dc-dc Charger (for Leisure Battery) -- How I Done It --


.
Fitted a bcdc1240 to my t5.1 and fitted and external led that it can drive to keep an eye on charging.

Quality bit of kit and preferred it to the ctek d250sa I fitted for my sister in her camper.
 
@rover220.....Still there.
I have a 69 plate DSG T6 too.
However to get the van to charge the starter battery as it’s factory additional battery under the seat which is controlled by a 100 relay via J519, to charge both batteries via the 13 pin socket I modified a relay which always has 30 and 87 connected and plug that in once the aux battery is charged to then charge the starter battery too.
When I need the van, I just fit the original 100 relay to have charging controlled via J519 as normal.
As I only have a 5A mains charger, I prefer not to stress it too much by hitting it with both low batteries at the same time.
 
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