johnlc Posted April 2, 2014 Share Posted April 2, 2014 I have the Plug-In Systems Power Management System 3 control panel and have a couple of queries in the hope that someone is familiar with it. I recently got my van and found that the two 85ah batteries were very dry. After topping them up with distilled water but not charging them, the PMS 3 battery level indicator was showing full! I do have a 60 watt solar panel fitted but this would not have charged the batteries even over a few days. I'm puzzled by this and suspect a fault in the PMS but don't know how to track it down. I'm considering buying two Banner 85ah batteries but want to know the PMS is indicating charge levels properly before I do. Any suggestions on identifying a fault with the PMS would be appreciated. The second query relates to battery charging as well The manual for the PMS 3 says it has a 13.8v battery charger. Given everything I have read about battery charging, both here and elsewhere, this would seem not to be enough to charge the batteries fully, as they need 14.4 to 14.8 volts. Is my understanding right? Does this mean I would not be charging brand new batteries properly with the PMS charger rather than a separate battery charger like a CTEK? I definitely don't want to spend £200 on two batteries just to find I am damaging them from the outset if I charge them only at 13.8 volts. Thanks in anticipation of your help Link to comment Share on other sites More sharing options...
Keithl Posted April 2, 2014 Share Posted April 2, 2014 Hi John, As no one else has replied yet I'll try and answer as best I can. First off your 'Battery level indicator' is nothing more than a volt meter and what you are actually reading is the output of your solar panel and NOT the state of charge of your battery. To measure your state of charge correctly you need to remove all loads and charging currents and leave to stand for a minimum of 1 hour. Then and only then will your Battery level indicator give a true reading. Second you are correct (certainly as I understand) that 13.8 volts is not sufficient to fully charge your lead acid batteries. I use a CTEK 8 stage charger to regularly top up my leisure battery. Finally get a good charger (eg the CTEK) and give your batteries a minimum of 24 hours charge, preferably individually, and then leave to stand for 24 hours and check voltage with a good DVM, if they are still over, say, 12.5 volts they should be OK. If you search this forum (or Google) you can find voltage versus state of charge to confirm their condition. If this overnight charge fails to achieve a good holding voltage then, and only then, replace them. I would not replace them until I had confirmed they were in fact duff. I'm sure others will now chime in with their comments but these are mine for starters. HTH, Keith. Link to comment Share on other sites More sharing options...
johnlc Posted April 3, 2014 Author Share Posted April 3, 2014 Keith Thanks for your response. I'm a bit puzzled that you say the battery level indicator is an indication of the output of the solar panel. I have a separate basic indicator for that, so don't understand what you mean - sorry. How do I remove all loads from the battery without disconnecting it? I realise I could then use the volt meter but it wouldn't allow the PMS3 battery level indicator to function? Sorry for my ignorance. I'm hopeless with electrics! John Link to comment Share on other sites More sharing options...
Keithl Posted April 3, 2014 Share Posted April 3, 2014 OK John, I'll try to explain in a little more detail. A very good measure of the state of charge of a battery is it's voltage at rest. So your battery level indicator is no more than a simple volt meter. But you are trying to measure the voltage with the solar panel connected so it is in effect 'on charge' and you are actually measuring the output voltage of the solar panel and not the 'at rest' voltage of the battery. You will have to disconnect the solar panel to remove the battery from charge then allow it to rest for an hour or more before you can check your state of charge via your PMS3 panel. Alternatively disconnect the battery entirely and check with a good DVM. Here is an extract from Wiki giving SOC versus voltage... Open-circuit voltage Approximate charge Relative acid density 12.66 V 100% 1.265 g/cm3 12.35 V 75% 1.225 g/cm3 12.10 V 50% 1.190 g/cm3 11.95 V 25% 1.155 g/cm3 11.70 V 0% 1.120 g/cm3 I hope this now makes sense but if not please do ask again. Keith. PS And be very careful of disconnecting and reconnecting your solar panel as I have heard warnings that they must be done in a correct manner (but I don't know any more as I haven't got one myself). Edit to add. Can you disconnect one battery at a time and bench charge and test off your MH then you will not have to disconnect your solar panel at all. Just be very careful of loose leads and spanners, do not short anything out! Link to comment Share on other sites More sharing options...
bluesprinter Posted June 3, 2014 Share Posted June 3, 2014 Hi John I can't offer any advice on your PMS at the moment, I've just bought a Mercedes Sprinter-based motorhome with a PMS3CDR system installed and have a fair few queries but note that you have a manual for your system - could you tell me where you sourced it please as I am currently searching high & low to find one ;-/ !! Many thanks Phil Link to comment Share on other sites More sharing options...
johnlc Posted June 4, 2014 Author Share Posted June 4, 2014 Phil Here is a link to the manual for the PMS in my van http://www.tonhauser.com/rubbersoul//images/PMS3%20User%20Manual.pdf I'm assuming it is the same as the one in your van but don't know. Someone who used to work for Plug-In Systems has a website with some basic info http://www.expluginsteve.co.uk/ I contacted him by phone with a couple of queries and he was helpful. Good luck! John Link to comment Share on other sites More sharing options...
Derek Uzzell Posted June 4, 2014 Share Posted June 4, 2014 Welcome to the Out&AboutLive forums, Phil. My understanding is that the PMS3 unit came in two formats - vertical or horizontal - and was thus referenced PMS3V or PMS3H. Both units functioned similarly and there are pictures showing both formats on the following link. http://www.grassroutesleisure.co.uk/products/223/bonus-power-management-system I'm guessing (and it really is a guess!) that your PMS3 unit is a 'bespoke' job and that the "CDR" relates to the motorhome's name (Compass "Commodore" perhaps?) Anyway, I can't find any on-line reference to a PMS3CDR but there are instructions for PMS3V/H units here: http://www.olearymotorhomes.co.uk/ekmps/shops/olearys/resources/Other/pms3-instructions.pdf (This is the same document as the one John provided, just a better quality image.) Link to comment Share on other sites More sharing options...
vick Posted August 28, 2015 Share Posted August 28, 2015 I also have a PMS 3H. It seems not to be charging the battery when connected to the mains. "Charger supply" switch is on and illuminated but there doesn't seem to be a 12V out from the unit. There is a fuse on the outside of the unti which is fine. There is another inside the unit but since it is sealed, it's difficult to check and not possible to replace, without drilling out all the rivets holding the case closed. Main supply is working fine. Any clues? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 29, 2015 Share Posted August 29, 2015 Welcome to the Out&AboutLive forums, Vic. Suggest you seek advice from the specialist company mentioned earlier in this discussion http://www.expluginsteve.co.uk/ There is a webpage relating to checking the charger http://www.expluginsteve.co.uk/Checking-your-chargerrepairs(1521199).htm This merely says that “The PMS3 charger is fused on the front panel” - no mention is made of an internal fuse. You need to be confirm (not just assume) that your PMS3 unit that is not working properly. If the charger has failed and the unit is genuinely not producing any charging output, it’s quite likely a replacement PCB will be needed. Link to comment Share on other sites More sharing options...
aandncaravan Posted August 31, 2015 Share Posted August 31, 2015 We repair the Plug in Systems range, like the PMS 3 and almost always the unit is damaged by the batteries. As your batteries are dry that is most likely why the charger has failed. However, don't just assume that it is the PMS that has overcharged the batteries, that is a very unusual fault for them. Please check both the Alternator voltage is right and that of the Solar Regulator. We see a lot of inappropriate Solar Regulators fitted that either don't back down the voltage when the batteries are full or continue to put out too much current. Some allegedly 'Motorhome' specific Solar Regulators are designed for a House roof installation. These Solar regulators can have a 'trickle' charge of several amps as they expect a continual draw on the batteries + a big battery bank that will tolerate the higher current. If you fit one of these in a Motorhome you will have less than satisfactory results. A Motorhome specific regulator expects a Motorhome to have long periods of inactivity, like in storage so the Solar regulators expect times when there will be no draw on the battery for months on end. They are therefore designed to have the ability to drop to very low voltage and current output when required and not overcharge the battery. Please take a look at our Solar Power page as it tells you how to identify a none Motorhome specific regulator and lists a 'power' meter (about £19? ). It is sold by another company, nothing to do with us so not a sales pitch, but it is one of the best we have seen as it shows both the current and voltage being output by the Solar panel so you can keep an eye on it. http://www.aandncaravanservices.co.uk/solar-power.php Also tells you how many amp hours your battery gets over a set period. Very easy to fit, it mounts remotely anywhere between the panel and the Power control unit/PMS/Battery. Do you have a B2B fitted elsewhere in the van as these can dry out batteries which may require constant topping up? One of our options in repairing the PMS unit is a modern multi stage charger assembly not the fixed 13.8v, 12a many have. Our more modern chargers are also more powerful and can support a bigger battery bank than the single 130Ah battery bank of many Plug in Systems units. Please can we suggest you don't fit a CTEK (we know lots of people rate them, but have you ever seen a proper test comparing these to other motorhome chargers?). We repair them so we know what is inside. A Motorhome specific Battery charger is much better value, they is designed for the Motorhome environment. A Motorhome specific Charger unit of decent 20A output will cost less than £100. Argos sell the CTEK 7amp charger at £159. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 31, 2015 Share Posted August 31, 2015 aandncaravan - 2015-08-31 12:45 PM We repair the Plug in Systems range, like the PMS 3 and almost always the unit is damaged by the batteries. As your batteries are dry that is most likely why the charger has failed... I suspect that your advice may to some extent fall on deaf ears as johnlc’s initial posting (that I’m pretty sure you are responding to) was in April 2014 and - as his most recent forum logon was last May - you may well not get a reply to your question about a B2B being fitted. I’m sure that vick (posting of 28 August 2015 12:58 PM) would welcome your help about his problem. Link to comment Share on other sites More sharing options...
aandncaravan Posted August 31, 2015 Share Posted August 31, 2015 Thank you, I did not look at the dates. You can tell I am a new user!! Hopefully it answers other peoples potential questions on the Plug In Systems kit? Link to comment Share on other sites More sharing options...
johnlc Posted September 1, 2015 Author Share Posted September 1, 2015 aandncaravan - thanks for your response to my query. I don't have a B2B charger fitted. I have since fitted two Banner leisure batteries and, whilst the 5 level indicator on the PMS seems a bit primitive I am certainly getting much better battery life from the new batteries. Best Wishes John Link to comment Share on other sites More sharing options...
Oliver.m Posted May 11, 2021 Share Posted May 11, 2021 Hello Everyone, we have a PMS3CD unit in our Fiat Ducato 2001 Bilbo conversion. I understand that there are different models etc and ours ends in "CD". Does anyone have a manual for this one too? Second Question: The Battery selector switch ( VEH / OFF / AUX) is faulty and needs replacing. I am not able to find an exact replacement with 3 positions but 4 prongs at the back! Please see picture attached. Does anyone know where to get this one? I already tried a few places and forums including ebay without success. Third Question: There seem to be 3 way switches with 3 prongs readily available, would it be possible to use this instead? On the attached picture it looks to me like the middle 2 prongs are connected anyway. Any help much appreciated and thanks for reading this! Best wishes, Oliver Link to comment Share on other sites More sharing options...
Derek Uzzell Posted May 11, 2021 Share Posted May 11, 2021 Welcome to the Out&AboutLive forums, Oliver. The PMS3CD unit was mentioned in this 2012 forum discussion (a lot of the links may now be out-of-date or inactive) https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/controle-panel/29731/ but I couldn’t find any data on that specific PMS3 unit even back then. The 2012 thread may still be useful for you though. (I notice that you’ve also asked about this on the Fiat Forum https://www.fiatforum.com/tech-talk/486917-3-way-switch-4-prongs-t85-pms3cd-fiat-ducato-2-8-jtd-bilbo-camper-conversion.html but I suspect that - as the PMS unit is not a Fiat part - you’ll be very lucky to get answers there.) Link to comment Share on other sites More sharing options...
mikefitz Posted May 11, 2021 Share Posted May 11, 2021 The 3 pin switch should work, however you will find that its a 230v AC rated switch at rated current, although it will function on a DC circuit at lower currents, long term reliability is in doubt. Before you replace the switch I suggest you investigate the blue butt crimp connectors, these are not original. It could be worthwhile rewiring further back into the unit so there is a sensible length of cable to the switch terminals. It may be the switch is OK and the wiring 'bodge' is causing issues. I think you will find there is only one usable center pin on the existing switch once you investigate further. (the 'stub' is part of the manufacturing process) The complete concept of the PMS3 design is flawed, and is designed for a 1980 caravan. I hope you are able to fix the unit but a more reliable alternative up to date power control center should be considered as a future enhancement. Mike Link to comment Share on other sites More sharing options...
mikefitz Posted May 12, 2021 Share Posted May 12, 2021 On reflection my comments regarding the blue crimps may be incorrect, rather than a modification they could be original. however it would still be useful to test they are correctly made and making good contact with the wire. Mike Link to comment Share on other sites More sharing options...
Oliver.m Posted May 12, 2021 Share Posted May 12, 2021 Hello Both, thanks a lot for your swift replies and support, much appreciated. I really like this Forum already :-D @mikefitz Yes you are right, I just had a look into the Unit and all other crimps look the same, so they are original. I will investigate the connections and report back. As a quick update, I have disconnected the switch now and realized that one of the prongs is a little bit loose and can move slightly. I presume this might have damaged the connection inside the switch and is creating the problem. I will get an alternative switch sorted. Last question: Do you think the below switch would fit in terms of Amperage? It is a 20A one. http://shop.apuljackengineering.co.uk/index.php?route=product/product&path=142_92&product_id=76 The original one says on the back which I didn't see at first: 15A - 125V a.c. 10A - 250V a.c. 10A - 28V d.c Size wise it should fit perfect and it also says for "PMS3" but just thought i pick your brains. Thanks in advance. Oliver Link to comment Share on other sites More sharing options...
mikefitz Posted May 12, 2021 Share Posted May 12, 2021 The switch should be a direct replacement for the existing switch. Its available from several sources including ebay, search using part number C1510AB. Although the specification is not perhaps ideal, the note on the data sheet suggests its tested to 20A at 28 volts. Mike Link to comment Share on other sites More sharing options...
Oliver.m Posted June 1, 2021 Share Posted June 1, 2021 Hello all, I have now repaired my PMS3CD unit again using the following switch: http://shop.apuljackengineering.co.uk/index.php?route=product/product&path=142_92&product_id=76 It is slightly smaller but you barely notice it. Thanks again for all your help guys! Best wishes, Oliver Link to comment Share on other sites More sharing options...
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