We need an Auto Electrician who understands Motorhomes.

[drmartinwhite]

Do you know how many amps/watts are drawn? We have a Merc Carthago and get 8w draw( see pictures) but the battery master upto now (10 months fitted) keeps the vehicle battery at about 12.6amps.View attachment 1003944
View attachment 1003945

Hi, your system from your screen indcates on that particular clouding day that your Solar panels are not producing enough Solar Voltage t start your MPPT (SmartSolar) to start charging your lithium habitation batteries, hence 0 W produces by the PV Charge (your MPPT). You are not on EHU, hence 0 W there. Your Lithium is at its rest voltage 13.26 (more or less I think) and lithium will hold that for quite a while as I understand. However, you are at 93% charge, when fully charges if calibrated right should be 990- 100%,, w=hnece you cn see the lithoun is being used. You can clearly see a DC load, and I assume that is your lithium supplying your starter battery with trickle charge presumably via a battery master. You can also see clearly, even over 3 days your starter battery dropping from a bout 12.8 to 12,6V. That will continue due to parasitic currents on the starter battery, very common on Mercedes MBUX systems, alarm, trackers, etc all connected to the starter battery. You don't show the battery history over 30 days which would be very interesting. I suspect you have sufficient solar to kick in your PV charger even on low daylight winter conditions. Sufficient to keep topping up your lithium, hence your starter always gets trickle charge. Nice system. You have convinced me to move to lithium and upgrade my solar as have the trickle charge problem where my system with AGMs simply can't charge the start well enough when in storage. Yours does, as you state fitted for 10 months now, and seen winter use keeping your starter at a healthy 12.6 average.

 

[Barry n Jackie]

I have read good things on here about Off-Grid Power Solutions and Vanbitz, and may yet just turn the van over to one of those with our wish list… once

Another Thumbs Up for Nigel and Roger at Off-Grid Power Solutions. Extremely pleased with the work they’ve done for me and they do Funster discount.

 

[Deafender]

Another Thumbs Up for Nigel and Roger at Off-Grid Power Solutions. Extremely pleased with the work they’ve done for me and they do Funster discount.

Thank you - And now that I’ve looked more closely at their website, they are under an hour’s drive from me as well… I’ll be giving them a call soon…

 

[DangerMousy]

Thank you, that was very informative. The dealer have told us that they have fitted a new battery. But as per my original post, they insist that nothing at all uses the engine battery and the fault is the Mercedes pulling power out.

I'm no electrical expert, but its possible that they're correct.

We managed to flatten the battery on our (Fiat) Carthago in only a few weeks when we'd forgotten to turn the EHU on after we got back from a trip. The media/TV button was switched off (its always off unless we're actively watching TV), but the drain from the tracker and alarm were enough to kill the engine battery (and that's without any smart/remote system).

We also used to have a Merc car with the Mercedes Me/MBUX system, and when on holiday (max 2-3 weeks at a time) we could almost guarantee getting a critical battery notification on our phones around the 2 week mark. Luckily it always started fine when we got home, but it demonstrates just how much energy the Mercedes Me system uses on standby, and if we'd been away for longer may have come back to a dead battery there too.

I'm assuming you have an alarm or tracker, so combine that with the Mercedes system, there's going to be quite a bit of battery drain when parked up unless its on EHU. Its probably fine for camping, but for storage you'll need to keep it plugged in.

 

[G1969]

Hi, your system from your screen indcates on that particular clouding day that your Solar panels are not producing enough Solar Voltage t start your MPPT (SmartSolar) to start charging your lithium habitation batteries, hence 0 W produces by the PV Charge (your MPPT). You are not on EHU, hence 0 W there. Your Lithium is at its rest voltage 13.26 (more or less I think) and lithium will hold that for quite a while as I understand. However, you are at 93% charge, when fully charges if calibrated right should be 990- 100%,, w=hnece you cn see the lithoun is being used. You can clearly see a DC load, and I assume that is your lithium supplying your starter battery with trickle charge presumably via a battery master. You can also see clearly, even over 3 days your starter battery dropping from a bout 12.8 to 12,6V. That will continue due to parasitic currents on the starter battery, very common on Mercedes MBUX systems, alarm, trackers, etc all connected to the starter battery. You don't show the battery history over 30 days which would be very interesting. I suspect you have sufficient solar to kick in your PV charger even on low daylight winter conditions. Sufficient to keep topping up your lithium, hence your starter always gets trickle charge. Nice system. You have convinced me to move to lithium and upgrade my solar as have the trickle charge problem where my system with AGMs simply can't charge the start well enough when in storage. Yours does, as you state fitted for 10 months now, and seen winter use keeping your starter at a healthy 12.6 average.

Hi, At the time of taking the screenshot, I had my solar turned off, I do this to drop the battery level to 80% or as I understand this is the optimal level for lithium when parked up and not in use, once it reaches this level I then switch back on. Below is a screenshot of the last 30day of my vehicle battery charge state, but as you can see this is a combination of driving/ plugged in to 240v and stood just trickle charge off the lithium.

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[Casper46]

Did they replace it with something else? Without the B2B, how will your leisure batteries get a charge when you’re driving?

Ian

I have no idea, that’s why I need someone to go through it and explain what is doing what.
Do other Mercedes owners go through the procedure of turning off the MBUK system when the vehicle is going to be left more that a couple of days. If we do that then we cannot use the Mercedes Me App to check what is happening to the vehicle.
The more I try to get in my mind what is best to do, then the more confused I am getting.
I do appreciate all your replies and thank you to everyone.

 

[drmartinwhite]

As far as Carthago ( dealer) is concerned it does not have a problem that is anything to do with them. They tell us that there is nothing Carthago wise that pulls power from the engine battery, and it is a Mercedes problem. After reading posts on Fun I do not believe them. As for it being under warranty just how many months of my life am I willing to spend driving too and from the dealers. The Motorhome could find its own way there, it has just been returned after being with them for 8 weeks. The front seats are dirty, the floor is covered in footprints and bits of gravel. After they delivered it back I rang them, firstly they said that it had been valeted before it left their premises, then they offered to valet it next time we called in. It is never going to happen.
Thanks for all your suggestions, we will start off with the one nearest to us.

It sounds like you have other problems beside the battery issues. This may be leading you to despair. Try to separate out the issues. I am not saying the dealer is correct, we have a Merc based Hymer and twice during the warranty period I had to diagnose electrical problems myself with multimeter and a DC clamp meter even getting advice and feedback for Schaudt experts and then presenting the evidence of electrical component failure to the dealer where they had to then address and fix the problem. They seemed unable with their service technicians to find the faults!

In your case if you can’t fault find your electrics your self it may well be worth taking on the service of a good auto electrician m, hence your post, and then use that evidence to present to your dealer before the warranty runs out.

Looking at your statement where you say the dealer says there is no fault on the habitation side, they may be right but a good motorhome auto electrician, and some funsters in here have point you at some, I don’t know any as I isolate the problem myself having originally trained as an electronic engineer. Anyway, I digress. I assume your motorhome is Mercedes based, if so they are notorious for parasitic currents discharging the starter battery. Mine takes about 90mA of parasitic current due to MBUx, alarms, tracker, etc. thus discharging the starter battery down to 12.4 V in about 10 days. This is an issue when storing the van, but not really a fault on the Mercedes side. really the issue is on the habitation side and while again not a fault there it is really just an inadequate charging system that can’t top up my AGMs I. Winter and hence efficiency trickle charge the starter. It’s frustrating and sometime you feel it is a fault but really it is an under specified system for the winter.

You don’t really explain what the issue is with your battery system. Perhaps you can tell us a bit more. What solar panels do you have, what is your solar charge controller, what type of habitation batteries do you have. … or have I missed this in an earlier post?

Hope that helps.

 

[DangerMousy]

Do other Mercedes owners go through the procedure of turning off the MBUK system when the vehicle is going to be left more that a couple of days. If we do that then we cannot use the Mercedes Me App to check what is happening to the vehicle.

No we never did that with our car: we wanted the alarm to be on, and to be able to monitor it remotely. We just crossed our fingers that it'd be ok until we got home

Fortunately we don't need to worry about it any more because we replaced that car with an EQC which automatically charges the 12v when needed from the traction battery. But much as I like these smart systems, I don't think they're suitable for vehicles that will be left up parked up for long periods of time unless you can leave them plugged in.

 

[drmartinwhite]

Hi, At the time of taking the screenshot, I had my solar turned off, I do this to drop the battery level to 80% or as I understand this is the optimal level for lithium when parked up and not in use, once it reaches this level I then switch back on. Below is a screenshot of the last 30day of my vehicle battery charge state, but as you can see this is a combination of driving/ plugged in to 240v and stood just trickle charge off the lithium. View attachment 1004861

Yes, nice that is what I expected to see. I am about to upgrade to Lighium and double or triple my solar as I have to put the van in storage and I can’t always get out every 10 days or so to take it for a drive, or put it on EHU. I reckon you could leave your’ solar all the time and not would probably keep the starter charge ok. I hadn’t heard about the 80% optimal charge value for Lithium in storage, I will research that. For me, I would expect the Solar charge to put the Lithium in float charge when Bulk has finished, same as when on EHU. Your Victron SmartSolar charger would be set up for Lithium charging profile, same as your EHI charger and your B2B charger when driving, so I don’t quite get the 80% bit.

However, it is great to see the graphs and convinced me of the need to upgrade now. Thanks.

 

[Casper46]

It sounds like you have other problems beside the battery issues. This may be leading you to despair. Try to separate out the issues. I am not saying the dealer is correct, we have a Merc based Hymer and twice during the warranty period I had to diagnose electrical problems myself with multimeter and a DC clamp meter even getting advice and feedback for Schaudt experts and then presenting the evidence of electrical component failure to the dealer where they had to then address and fix the problem. They seemed unable with their service technicians to find the faults!

In your case if you can’t fault find your electrics your self it may well be worth taking on the service of a good auto electrician m, hence your post, and then use that evidence to present to your dealer before the warranty runs out.

Looking at your statement where you say the dealer says there is no fault on the habitation side, they may be right but a good motorhome auto electrician, and some funsters in here have point you at some, I don’t know any as I isolate the problem myself having originally trained as an electronic engineer. Anyway, I digress. I assume your motorhome is Mercedes based, if so they are notorious for parasitic currents discharging the starter battery. Mine takes about 90mA of parasitic current due to MBUx, alarms, tracker, etc. thus discharging the starter battery down to 12.4 V in about 10 days. This is an issue when storing the van, but not really a fault on the Mercedes side. really the issue is on the habitation side and while again not a fault there it is really just an inadequate charging system that can’t top up my AGMs I. Winter and hence efficiency trickle charge the starter. It’s frustrating and sometime you feel it is a fault but really it is an under specified system for the winter.

You don’t really explain what the issue is with your battery system. Perhaps you can tell us a bit more. What solar panels do you have, what is your solar charge controller, what type of habitation batteries do you have. … or have I missed this in an earlier post?

Hope that helps.

Thank you for your post.
We have not managed to get the engine battery to hold up for more than two or three days. I have posted a few times in the last few months. We do not have a tracker, our MH is parked in a garage therefore our solar doesn’t work. We have 2x80 amp habitation batteries. Summer time and travelling every couple of days is ok, winter time with no sun and no hook up limits our stays away. We have a Votronic battery computer with `Smart Shunt and a Victron MPPT Solar charger. I have little idea of what I am looking at when I read them, that is why I need a tutorial on the Motorhome electrical system.

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[G1969]

Yes, nice that is what I expected to see. I am about to upgrade to Lighium and double or triple my solar as I have to put the van in storage and I can’t always get out every 10 days or so to take it for a drive, or put it on EHU. I reckon you could leave your’ solar all the time and not would probably keep the starter charge ok. I hadn’t heard about the 80% optimal charge value for Lithium in storage, I will research that. For me, I would expect the Solar charge to put the Lithium in float charge when Bulk has finished, same as when on EHU. Your Victron SmartSolar charger would be set up for Lithium charging profile, same as your EHI charger and your B2B charger when driving, so I don’t quite get the 80% bit.

However, it is great to see the graphs and convinced me of the need to upgrade now. Thanks.

Ref 80% see previous thread

Lithium LifePO4 charging regime, I’m confused!

This site has a wealth of info on Lithium leisure batteries and their care. I’ve trawled through a lot of it over the last week or so. There are evidently many very well-informed people posting with an obvious in-depth expert knowledge on the subject that I respect. There seems to be a...

www.motorhomefun.co.uk

 

[bigtwin]

Do other Mercedes owners go through the procedure of turning off the MBUK system when the vehicle is going to be left more that a couple of days. If we do that then we cannot use the Mercedes Me App to check what is happening to the vehicle.

Suzukikettle, what’s your experience of the system?

Ian

 

[DerfelUK]

Our Motorhome had just returned back from the dealers after being there for 8 weeks. We are no further on regarding battery power or lack of it.
We would like to find someone who could check what is what and explain to us how both the habitation and engine batteries take power.
We are not sure that some auto electricians would necessarily understand the workings of the Carthago habitation system. Carthago are blaming Mercedes as usual.
Any suggestions please, preferably in the Yorkshire area, but we will travel if needs be.
Just want it sorting before it is 2 years old as we have had problems since new.

I will just add my experience, unrelated to Carthago or Mercedes, but a Fiat B544 Hymer.
I went through brand new starter batteries before I did a strip down, by removing both habitation and starter batteries. One of the habitation batteries was blown and not taking charge.
The fault turned out to be the incorrect solar controller that directly connected the two systems, engine and habitation.
Changing the Solar controller that separated the two sides solved the issues.
Sometimes it can be the most simple of things, just needs methodical diagnosis.
Good luck!

 

[Stans Van]

Our Motorhome had just returned back from the dealers after being there for 8 weeks. We are no further on regarding battery power or lack of it.
We would like to find someone who could check what is what and explain to us how both the habitation and engine batteries take power.
We are not sure that some auto electricians would necessarily understand the workings of the Carthago habitation system. Carthago are blaming Mercedes as usual.
Any suggestions please, preferably in the Yorkshire area, but we will travel if needs be.
Just want it sorting before it is 2 years old as we have had problems since new.

Speak to Ash at Van-Bitz