Dacswells Posted September 21, 2020 Share Posted September 21, 2020 Hi all, we picked up our new Knaus Boxstar over the weekend and, leaving aside the poor service received from the dealer, we were sat in the van yesterday morning 'playing with things' and noticed that the control panel showed that the main battery was almost dead, while the leisure battery was fully charged. We promptly started the engine and tried to charge the battery; engine started first time but the main battery didn't show any signs of charging. Later on we plugged the EHU in and both batteries showed as fully charged. Once we turned the EHU off the main battery retained to showing as 'empty';I willingly admit that I am totally confused; any ideas what might be going on? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 21, 2020 Share Posted September 21, 2020 Welcome to the Out&AboutLive forums, Damian. Are you sure that you don’t need to ‘program’ your new motorhome’s electrical system to reflect the batteries fitted to it? If so, it should (hopefully) mention this in the Owner Manual. As you were able to start the vehicle’s motor with no sign that the starter-battery was badly discharged, it’s reasonable to assume that the control-panel is misreading and that there’s nothing significantly wrong. (I’ve altered the title of your question as I know one forum (Brian Kirby) has a recent-ish Boxstar 600 and should be au fait with Knaus motorhome electrics.) Link to comment Share on other sites More sharing options...
Dacswells Posted September 21, 2020 Author Share Posted September 21, 2020 Thank you for coming back so quick Derek. Although I was unaware that such an action was necessary (I am just beginning to appreciate the steep learning curve we are going to have to go through!), I would have expected that to be done as part of the pre-delivery inspection and set up from the dealer. I will head to the manuals! Link to comment Share on other sites More sharing options...
Robinhood Posted September 21, 2020 Share Posted September 21, 2020 Other than a failed control panel or a wiring issue, I can think of one scenario (with a question) that might fit what you describe. I'm assuming CBE electrics here (though others might be similar) If the vehicle battery was giving no reading except when on hook-up, then I would suspect the fuse protecting the on-board charging circuit to the vehicle battery. This is likely to be close to the vehicle battery and should be a relatively high rating. I suspect the charging circuit is also used to show the battery voltage, so a failed fuse here would prevent vehicle battery charging and also show a zero voltage (under all circumstances except when on EHU, where I suspect the voltage being delivered by the charger, but not reaching the battery due to the open circuit, would be shown - it is common for both batteries to show a decent state of charge when on EHU, as it's the charging voltage, not necessarily the battery voltage). It isn't unknown for dealers to remove such main fuses to avoid current draw before sale. Link to comment Share on other sites More sharing options...
Dacswells Posted September 21, 2020 Author Share Posted September 21, 2020 Hi Robinhood, thanks for the response. I can confirm that there was no reading from the vehicle battery. The dealer has other issues to put right on the van, sounds like this is another that is going to be added to the list *-) Link to comment Share on other sites More sharing options...
Brian Kirby Posted September 21, 2020 Share Posted September 21, 2020 Dacswells - 2020-09-21 3:06 PM Hi all, we picked up our new Knaus Boxstar over the weekend and, leaving aside the poor service received from the dealer, we were sat in the van yesterday morning 'playing with things' and noticed that the control panel showed that the main battery was almost dead, while the leisure battery was fully charged. We promptly started the engine and tried to charge the battery; engine started first time but the main battery didn't show any signs of charging. Later on we plugged the EHU in and both batteries showed as fully charged. Once we turned the EHU off the main battery retained to showing as 'empty';I willingly admit that I am totally confused; any ideas what might be going on? Can you say which control panel you have, and whether it is by CBE? You should have a manual for the panel in your Knaus info pack, and that should confirm both manufacturer and model. Failing that, look in the index of the Knaus manual where it should be mentioned under "Power supply". In our manual it is on page 72 where, in the note on page 73, it says: "You will find further information in the separate Operating Manual supplied by the manufacturer.". Ours came with both Knaus and CBE panel manuals, plus that for the CBE charger. Link to comment Share on other sites More sharing options...
Dacswells Posted September 22, 2020 Author Share Posted September 22, 2020 Hi Brian, thanks for that. It is a CBE panel. The battery does seem to be holding its charge - for example starting first time, so I guess it is a panel problem. I have just spoken to the dealer and we will be returning the van to them to get this, and other number of other shortfalls, sorted. Can I add a quick thank you to all of you who have offered support. We have be waiting for delivery of the camper van since April and I have been lurking on the edges of the forum waiting for the day I could join in. I have been impressed by the knowledge and general friendliness. Thank you. Link to comment Share on other sites More sharing options...
Brian Kirby Posted September 22, 2020 Share Posted September 22, 2020 You're welcome. I suspect Robinhood is correct about the fuse on the starter battery charging circuit. I'm unsure whether your van will have the same control panel as ours (CBE PC110-KN), but if it has, pressing the centre button on the left hand side of the panel (with the "chassis" pictogram on it) should give a reading of the battery state, and if the battery were heavily discharged the second warning light from the left at the top of the panel (carrying the same pictogram) should be flashing red. As neither appears to be happening it seems the control panel can't "see" the starter battery. A pulled or blown fuse on the charging circuit for the starter battery (under a trap in the front passenger's footwell) seems a good first bet. The starter battery only gets a trickle (or float) charge from the charger when on EHU, so if it has become heavily discharged due to absence of that input before you got it, it will need to be driven for some distance to get its charge level up to scratch. See what it is showing after the dealer has fixed the problem. Ours only shows full charge after several 10's of miles driving, and always otherwise shows less than full charge even when on EHU. The leisure battery, OTOH, which is charged at a higher rate for the first few hours on EHU, will show full charge. You may find that with the control panel energised (top press button on the right hand side of the panel) the low water level warning (second warning light from the right at the top of the panel) continually flashes when the fresh water tank is drained. Rather than leaving the panel on with this continually flashing when the van is not in use, I have found it best to turn the panel off. I discovered that leaving it on with an empty tank eventually resulted in the panel locking up, for which the cure was to pull the fuse on the power feed to the panel. The fuseholder for that fuse, on our van, is attached by two cable ties to one of the leisure battery restraining straps (inside the front passenger's seat base behind the front drop down access flap). You have to first pull off the fuseholder cap to reveal the fuse. Should this happen on yours, just remove the fuse, leave it out for a few minutes, and then re-insert it. The control panel should then have re-set. Then turn the control panel off and leave it off until you next fill the fresh water tank! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 22, 2020 Share Posted September 22, 2020 Image of the ‘generic’ version of the CBE PC110 control-panel is attached below. (The PC110-KN Knaus version may be a slightly different.) There is a German forum entry about a problem with the PC110-KN panel (GOOGLE Translated link here) https://translate.google.co.uk/translate?hl=en&sl=de&u=https://www.wohnmobilforum.de/w-t139832.html&prev=search&pto=aue but I’m not sure it’s relevant. Link to comment Share on other sites More sharing options...
Dacswells Posted October 15, 2020 Author Share Posted October 15, 2020 just for completeness. The van has been returned and the problem was, as explained to us, 'a faulty brown fuse' which has been changed and the battery is now charging, albeit we have not yet seen it charged fully (after a 120 miles- 75 of which was continuous driving - the control panel still suggested that the battery was still not quite fully charged - it was on the first light of the 3/3 section). Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 16, 2020 Share Posted October 16, 2020 I wouldn’t be too concerned about your control-panel’s battery-voltage reading. My Fiat Ducato-based Rapido has a CBE PC180 panel (image attached below) that uses a similar non-numeric LED system to indicate the voltage of the vehicle’s starter battery or leisure battery. When the Rapido’s motor is running and the starter and leisure battteries are both being charged with a 14+ voltage via the vehicle’s alternator, all of the panel’s four green LEDS illuminate when the ‘check voltage button’ for each battery is pressed. When the Rapido is connected to a 230V power-supply (eg. a campsite electric hook-up) and the onboard CB516 battery-charger is operating, all of the four green LEDS illuminate when the ‘check voltage button’ for the leisure battery is pressed, but only three of the four green LEDS illuminate when the ‘check voltage button’ for the starter battery is pressed. This is to be expected as the leisure battery will normally be receiviing a 14+ voltage, but the starter battery will just be getting a low amperage, lower voltage maintenance charge. When both of the Rapido’s batteries have been fully charged and are no longer receiving charge (and the batteries have ‘rested’ for several hours) I expect to see a three green LEDS voltage readout for the leisure battery and a two green LEDS voltage readout for the starter battery. The Rapido has two brand-new Varta wet-acid batteries and, if they were removed, fully charged, ‘rested’ and voltage checked with no load placed on them, the voltage would probably be around 12.8V for both batteries. The lower ‘green LED’ voltage reading for the starter battery when in situ is probably because it is maintaining dashboard stored data, plus the starter battery is in the vehcle’s cab, while all the CBE gubbins is near the vehicle’s rear and close to the leisure battery in the rear garage. The implications of the above are that four green LEDs will illuminate only when the CBE system detects a voltage of around 14V, three green LEDs will illuminate if the voltage detected is somewhere between 12.8V and 13.5V, and two green LEDs will illuminate if the voltage detected is between 12.5V and 12.8V. But if there’s a load on the battery (eg. maintaining dashboard stored data) this will affect the control-panel’s readout and may well give the impression that a battery is not fully charged even when it is. Possibly the best way for you to cross-check the control-panel’s readout for the starter battery would be to fully charge that battery while it is in situ with a separate charger connected to the battery terminals (and WITHOUT the onboard charger running) let the battery rest afterwards and see what the panel then displays. I occasionally do this with my Rapido using a CTEK MXS 5.0 charger, which causes four green LEDs to appear on the control-panel while the battery is being charged. However, once I’ve disconnected the CTEK charger and let the battery rest, the control-panel’s voltage readout for the starter battery always reverts to two illuminated green LEDS. It’s like Elliot Aronson said - it’s not what people say, it’s what they mean ;-) Link to comment Share on other sites More sharing options...
Alanb Posted October 16, 2020 Share Posted October 16, 2020 Derek Uzzell - 2020-10-16 8:38 AM ===================================================================================== When the Rapido is connected to a 230V power-supply (eg. a campsite electric hook-up) and the onboard CB516 battery-charger is operating, all of the four green LEDS illuminate when the ‘check voltage button’ for the leisure battery is pressed, but only three of the four green LEDS illuminate when the ‘check voltage button’ for the starter battery is pressed. This is to be expected as the leisure battery will normally be receiviing a 14+ voltage, but the starter battery will just be getting a low amperage, lower voltage maintenance charge. ===================================================================================== The usual CBE arrangement for charging the starter battery from the CB516 battery charger consists of a relay operated via the mains ON, or "S" wire from the battery charger, in series with a current limiting (2A) thermistor, and a blocking diode to prevevent the possibility of the starter battery discharging into the habitation battery. The diode will have a minimum voltage drop of 0.4V across it. Hence the starter battery voltage will always be at least 0.4V lower that the habitation battery voltage, when both batteries are being charged via the CB516 charger. Alan Link to comment Share on other sites More sharing options...
Dacswells Posted October 16, 2020 Author Share Posted October 16, 2020 Great advice. I had not appreciated that I would be on such a steep learning curve ;-) Link to comment Share on other sites More sharing options...
DavidG Posted April 14, 2021 Share Posted April 14, 2021 Hi! did replacing the fuse solve the problem without any recurrence? Our Boxstar also came with this 'feature', but replacing the fuse only cures the problem up until we drive the vehicle... and then the fuse blows again! Pre-delivery, we had a second battery installed and we are suspecting a short circuit somewhere... We took delivery last September, but can't get back to the German dealer (we're in Switzerland), so we are living with the issue for now - van has started reliably all winter :-D Link to comment Share on other sites More sharing options...
Brian Kirby Posted April 14, 2021 Share Posted April 14, 2021 David, the fuse in question was on the starter battery. As you've referred to having a second battery installed, I'm assuming your problem is with a fuse at the habitation battery? It might help if you could clarify if that is correct, and also whether your BoxStar is the same model as the OP's. The reason the fuse is blowing will be that the circuit is carrying too high a load. It may just be a wrongly rated fuse, but it would not be safe to fit a higher rated fuse without checking for an actual fault. The important thing is to identify why the charging load is higher than the installed fuse fuse can tolerate. Under present circumstances, if you can't get the van to the German dealer, according to the Knaus website there are 10 Knaus dealers reasonably well distributed around Switzerland, who should know their way around the electrics. Perhaps one near you? Plainly something is wrong at present, and without knowing what that "something" is, I think it is probably unwise to rely on the fuse blowing to prevent consequential damage. Link to comment Share on other sites More sharing options...
Dacswells Posted April 16, 2021 Author Share Posted April 16, 2021 Hi David, replacing the 'brown' fuse in our van does seem to have resolved the problem, both the leisure and the main battery are charging both when we are driving and when we put it on a mains charge. When we were chatting with the dealer about the problem, they did seem to think it was quite a common problem. Link to comment Share on other sites More sharing options...
bertievansmallhousen Posted June 2, 2022 Share Posted June 2, 2022 Hi all, We are new to all this. Just picked up our Knaus Boxstar 540 and we are having exactly the same problem. Does anybody know whether or not this was resolved, and how? Link to comment Share on other sites More sharing options...
Alanb Posted June 2, 2022 Share Posted June 2, 2022 I have not looked at this thread for sometime, but as it has been resurrected by the previous poster, I have read it again. The problem on Dacswells MH was solved by replacing a failed "brown" fuse, and by the description of its mounting position I assume that it was either a standard blade fuse with 5mm blades & 19mm body, or a maxi blade fuse with 8mm blades & 29mm body. CBE recommend 50A fuse rating for both B1 (starter), and B2 (habitation) battery connections. A standard blade fuse of brown colour has a rating of only 7.5A, whereas a brown maxi fuse is rated at 70A. The 7.5A rating is too low, while the 70A rating is too high. A fuse does not blow instantly if its rated current is exceeded by a small amount, so a 7.5A starter battery fuse may survive the alternator charging current flowing into one habitation battery, but not when two batteries are fitted. With CBE system, the fridge element supply is taken from the B2 side of the split charge relay, but only when a voltage above about 13.2V indicates that the alternator is charging, and the fridge is selected to 12V. In this state the B1 fuse will be carrying the fridge current of about 13A, plus the charging current for B2. I would not expect a 7.5A rated fuse to survive. Standard blade fuses are available with a 40A rating, which are coloured orange. Maxi blade fuses are available rated at 20A upwards, with the 50A versions being red in colour. It may be worth noting that when I fitted a B2B in conjunction with my CBE system, I arranged to interrupt the B1 connection when the engine was running. I can still see a reading for B1 voltage on the PC200 control panel, but this reading is spurious. Alan Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 3, 2022 Share Posted June 3, 2022 bertievansmallhousen - 2022-06-02 1:46 PM Hi all, We are new to all this. Just picked up our Knaus Boxstar 540 and we are having exactly the same problem. Does anybody know whether or not this was resolved, and how? Tom, if your Boxstar 540 is new, the simplest remedy will be to return it to the dealer to sort out under warranty. If not new then the selling dealer should be still be liable for the problem under consumer legislation. If bought privately, then it would be helpful to know what year the van is, and also (assuming you have the Knaus and CBE handbooks), what version of CBE's control panel and distribution board are present. On our Boxstar 600 Street both items have a "KN" suffix, indicating that they have been modified to Knaus' requirements, and I would expect yours to be similar. Link to comment Share on other sites More sharing options...
bertievansmallhousen Posted June 3, 2022 Share Posted June 3, 2022 Brian. Thanks for the reply. It's brand new - 71 plate. The problem started after we had had it back to the dealer to sort out a couple of other issues: bathroom light permanently on, parking sensors working intermittently, and wifi with no DC feed. They are resolved now, but now we have this new issue. I was hoping there was a known / common problem which needed a quick reset or a fuse that can be easily accessed etc., so that I could sort it, or have a more helpful/informed informed discussion with with the dealer. The panel is the CBE PC110-KN and the he distribution board is also CBE: DS300KN Part of my problem is that I am immunosuppressed so have to limit my contacts with people as much as possible. Unfortunately, I think you are probably right - sounds like another trip. At lease we have an excuse to go out for the day again. Cheers Tom Link to comment Share on other sites More sharing options...
bertievansmallhousen Posted June 3, 2022 Share Posted June 3, 2022 Many thanks for your reply. That makes a lot of sense. I think I will take it back under warranty ( another 200 mile round trip), but at least I am now more informed. Thanks guys. Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 3, 2022 Share Posted June 3, 2022 bertievansmallhousen - 2022-06-03 5:42 PM...............................The panel is the CBE PC110-KN and the he distribution board is also CBE: DS300KN............................ Cheers Tom That is the same as ours (hardly surprising - but you never know!) and I have not experienced similar problems. I assume you are experiencing failure of the starter battery (not the leisure battery) to charge as indicated by the PC110? Even if you try pulling and testing each fuse in the DS300 and find one that has blown it won't tell you why it blew, and ideally the cause needs investigating before the fuse is replaced. If the dealer has left the van standing over an extended time without either disconnecting the batteries, periodically running the engine for an hour or so, or connecting mains to the on-board charger, the batteries will have suffered. The starter battery is permanently running the Fiat on-board electronics, which can drain it quite quickly as it is a 24/7 load although the hab. battery shouldn't have an connected load so will only suffer self-discharge over time. Once the engine is stopped, a relay separates the two batteries from each other so that use of the hab. battery can't pull down the starter battery charge. When the engine is next started, that relay performs the opposite function and links the two batteries so that the alternator charges both. If the dealer has allowed the starter battery charge to fall to the extent the van wouldn't start he may have jump started it and then run it for a while to ensure it started OK when you were collecting it. In that case the alternator will have delivered a very high charging current to the near flat starter battery that may have caused a fuse that wasn't rated for that Amperage to blow so cutting off the starter battery from the alternator. If that was all that had happened it would be reasonable to charge the battery separately, then replace the burnt out fuse, and then start the engine. Problem is, who knows? So, if the hab. battery shows a satisfactory charge level when the van is not connected to mains, and the starter battery shows flat, the relay should be functioning as intended. (If the control panel battery state indications are used when the van is on mains they will merely indicate the rate of charge from the charger, and not the charge state of the batteries. So, to see the battery charge state the mains must first be disconnected.) So, I think the dealer needs to investigate what is causing the flat starter battery and either Fiat, the dealer, or Knaus need to put it right at whosever cost is the culprit! Link to comment Share on other sites More sharing options...
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