Battery Drain - help!

[DavidWNE]

I have a factory fitted AGM battery on my T6.1 and I've noticed recently that the volts are dropping by up to 0.2V per day.

My set up is a 75 amp AGM leisure battery with Redarc DC-DC (to bypass the smart alternator) and PU 170w solar panel, a feed for my Sergent with isolation switch, direct feed for my Autoterm Planar diesel heater, an FMT100 GPS tracker and a victron 240v Charger (Bluetooth version).

I converted the van myself over the summer and due to having solar never noticed the issue and the battery would always sit at around 12.9/ 13V if not in use.

The difficulty is is that I'm currently abroad and will be for a number of months more. My dad is taking the van for a run out every week or so which boosts the battery back up to 13.1V but is then dropping off (I'm monitoring the battery volts from the Tracker App).

I have already isolated the Sergent PMS via the feed isolation so nothing is being drawn from the camper electrical system.

Im hoping for some help with the below please to assist in diagnosing the issue:

1. Am I right in thinking that there will be no benefit / amps produced by the solar panel at this time of year? (I.e. not enough to maintain the tracker etc.)

2. The tracker spec details that it can use up to 26 MA, surely this wouldn't cause battery drain to the extent I'm seeing?

3. Without solar input what volt level would you expect my AGM to sit at?

4. Does the Redarc DC-DC draw any amps when the van is not in use (possibly the solar controller element?)

5. Does the Planar Heater draw amps when not in use (Permanent feed to battery but heater not in use)

6. Could the 240v Victron charger be drawing amps when not in use (something to do with the Bluetooth element maybe?)

All of the above seem unlikely to me however I would very much appreciate your thoughts and/or any other suggestions. Ideally I would isolate each system to find the cause of the issue but being out of the country means this isn't possible.

The van is only 6 months old so wouldn't imagine the battery is the issue unless faulty.

Thank you in advance.

Cheers,
David

 

[Dellmassive]

A. what battery is dropping? - the leisure battery? , you mantion its the starter battery monitored from the tracker?
B. what Redarc do you have ? 20A 40A 50A?
C. my van starter battery will last about 3weeks before going flat and needing a jump start - some ppl have said 4-5weeks.

+++


1. if its grey and cloudy your PV will show good voltage but produce next to no current - so next to no charge.

2. 26mA is way to low a quote more like 75-150mA - this will be the source of you drain most likely. (use a clamp meter to monitor)

3. van will keep it at 80% SOC with regular use, mine sits at 12.2v - Battery Monitoring -- How I Done It --

but AGM volts will drop faster when battery has a lower SOC.

4. possibly . . I've not tested this, but unlikely to cause battery drain, the Redarc will try to use PV to charge the starter battey, but is PV is too low . . . . ?.

5. dont know - anyone with one able to answer this? ( id assume that it doesnt)

6. No, its only alive when powered by 240vac.

+++

My dad is taking the van for a run out every week or so which boosts the battery back up to 13.1V but is then dropping off (I'm monitoring the battery volts from the Tracker App).

- how long is the drive . . ?

a quick drive wont recharge the battery properly/enough . . . it will be better to leave connected to a smartcharger for 24hrs once a week/month - Battery Charging - Main Battery Earth Point -


+++


post some pics of your van and setup.


more info here: Dellmassive’s "How I Done It" blogs.

.

 

[Dellmassive]

FYI -


the tracker spec states:


25mA - no load ( so in sleep mode )

to

250mA - full load ( awake and transmitting data )



so, depending on how often its reporting its location etc it will use more power - ill assume this is you main source of the battery drain?


i run a tracker on mine, with some USB chargers etc and will get the three weeks mentioned above.



any USB chargers connected anywhere?

https://teltonika-gps.com/downloads/en/fmt100/FMT100_Quick_Manual_v1.5.pdf

 

[mmi]

the volts are dropping by up to 0.2V per day.

What's the battery voltage next day, after 3 days, after 5 days the van has been driven (but not "touched", e.g. doors opened, etc)?

 

[DavidWNE]

A. what battery is dropping? - the leisure battery? , you mantion its the starter battery monitored from the tracker?
B. what Redarc do you have ? 20A 40A 50A?

2. 26mA is way to low a quote more like 75-150mA - this will be the source of you drain most likely. (use a clamp meter to monitor)

3. van will keep it at 80% SOC with regular use, mine sits at 12.2v - Battery Monitoring -- How I Done It --

but AGM volts will drop faster when battery has a lower SOC.

Firstly thank you for your extremely helpful reply! This forum really is fantastic. I have replied to your responses below:

A - the tracker is fitted to the factory fitted Leisure Battery not the starting battery so the readings I'm getting are from the leisure battery. Am I right in thinking that because I have installed the Redarc that the Leisure battery will now charge all the way up to 100% rather than 80%, whilst the starter will charge up to 80% for regenerative breaking etc.?

B - it's the Redarc BCDC1225D so 25A

2. I had expected the tracker to draw the 24MA in standby as the van isnt moving except for when the app is being used to check for updates. Maybe it's sending more regular updates than I thought it would.

3. As in response to point A would the leisure Battery not sit at 100% / c13v now that the Redarc is fitted and not relying on the factory fitted relay? (Assuming nothing is drawing current)

The van is being taken for a good 10/15 mile drive at least, would this be enough? My brother borrowed it for a trip to the lakes at the weekend and the leisure battery is draining the same as previously.

Thanks again for your help it is much appreciated!

 

[DavidWNE]

What's the battery voltage next day, after 3 days, after 5 days the van has been driven (but not "touched", e.g. doors opened, etc)?

The van was driven for 2hrs on Friday, when parked up at 4pm it was at 13.1V, 24hrs later it had dropped to 12.8v. It then dropped to 12.7v last night but has gone back up to 12.77v now however I believe its a sunny day at home and could be due to solar.

Before its latest trip out on Friday the battery had dropped from 13v all the way down to 12.11v at its lowest which I believe took around 4 days. I then bottled it and asked my dad to take it for a good drive.

I'm considering keeping a log over the coming days and see how the battery performs. Im kicking myself for not fitting a proper battery monitor before I left the country!

 

[Dellmassive]

A- Correct

B - ok, they great . . . i have the 50D

c -2 mostlikly . . . mine updates every 10sec

d - yes . . . charged voltage will be 13.6v, but the battery rest voltage after charge will drop to 12.8v / 12.6v or so, assuming its 100% soc after a good 24hr charge.

The redarc is only 25A charge max. . . that will take approx 5 hours to charge a flat 100A AGM battery at max rate, but more likely 10-15hrs as the current drops off.

hence the question about how long your dad drives the van for ? - im sure its not 5hours.

so its best to plug into the mains and let your Victron smart charge top the battery up to 100%, then let the van sit for 2-4 weeks, then repeat.

a short drive will only replenish a few % Soc.

.

The van is being taken for a good 10/15 mile drive at least, would this be enough? My brother borrowed it for a trip to the lakes at the weekend and the leisure battery is draining the same as previously.

- thats good as it will help keep the engine and mechanicals in good order while you are away.

 

[DavidWNE]

A- Correct

B - ok, they great . . . i have the 50D

c -2 mostlikly . . . mine updates every 10sec

d - yes . . . charged voltage will be 13.6v, but the battery rest voltage after charge will drop to 12.8v / 12.6v or so, assuming its 100% soc after a good 24hr charge.

The redarc is only 20A charge max. . . that will take approx 5 hours to charge a flat 100A AGM battery at max rate, but more likely 10-15hrs as the current drops off.

hence the question about how long your dad drives the van for ? - im sure its not 5hours.

so its best to plug into the mains and let your Victron smart charge top the battery up to 100%, then let the van sit for 2-4 weeks, then repeat.

a short drive will only replenish a few % Soc.

.



- thats good as it will help keep the engine and mechanicals in good order while you are away.

That all makes complete sense thank you. I hadn't considered that it would take 5hrs of driving to replenish the leisure battery from empty / 2.5hrs + from 50%.

I'll get it plugged in to the victron smart charger for 24hrs and monitor it again this week. It does sound like it could be the Tracker is the cause if anything.

On a completely different subject have you noticed if your redarc has a slight wining sound sometimes when accelerating or braking? Mine is located under the passenger seat and does whine and its quite noticeable if the radio is off. I had a look on Google and couldn't find anything from the UK but some discussion on Australian forums (not nessacerily DC-DC chargers specifically but redarc units).

Thank you!

 

[DavidWNE]

post some pics of your van and setup.


more info here: Dellmassive’s "How I Done It" blogs.

.

I haven't got any photos of the battery compartment set up but I've attached some of the van in general.

First time conversion and never done anything like this before but really enjoyed the challenge. Did everything myself except the pop top.

T6.1 in Ascot Grey and Burgundy top.

Definitely my best purchase to date! Cost an arm and a leg but no regrets

 

[Dellmassive]

note the voltage drop offs after the engine run / battery charge.

Battery Monitoring -- How I Done It --

Battery Monitoring -- How I Done It -- Part #1 Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends...

www.t6forum.com

 

[Dellmassive]

have you noticed if your redarc has a slight wining sound sometimes when accelerating or braking? Mine is located under the passenger seat and does whine and its quite noticeable if the radio is off

- i hadnt noticed before,

I've got the ctek d250se in the van at the min . .

im due to swip it out for the redarc soon . . . so ill keep any eye , or ear out.

possibly the high frequency switching FETS? when its under load - have you got very good hearing?

can you get a clip of it on video from your mobile and post a link to it?

 

[Dellmassive]

I haven't got any photos of the battery compartment set up but I've attached some of the van in general.

First time conversion and never done anything like this before but really enjoyed the challenge. Did everything myself except the pop top.

T6.1 in Ascot Grey and Burgundy top.

Definitely my best purchase to date! Cost an arm and a leg but no regrets

View attachment 140238

View attachment 140239

View attachment 140240

View attachment 140241

View attachment 140242

the van looks great . . .

have a look at the evenmts page and see if you can come to one of the meet ups - Upcoming VW Events



and

Happy New Year T6F - 2022 -

Happy New Year T6F - 2022 - well its that time again . . . New Years eve 2022. +++ 2021 has been a challenging year, with the Covid-19 thing, that was then covid-20, then covid-21 and now most likely covid-22. 2021 has been the year of Vaccines and jabs, followed by Lock-downs and...

www.t6forum.com

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[Dellmassive]

note the voltage drop offs after the engine run / battery charge.

Battery Monitoring -- How I Done It --

Battery Monitoring -- How I Done It -- Part #1 Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends...

www.t6forum.com

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[Higgidav]

My Planar does draw on the leisure battery when parked with the heater off. I’ve not monitored it closely as I have a Smart Battery Protect to turn off everything when I’m not using the van. On the odd occasion I have not disabled the load with the Battery Protect I have noticed a steady voltage decline on the BM2.

You could try pulling the fuse to the Planar.