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Ducato starter battery


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Hi, my starter battery (2012 ducato) appears to be past it's best. It starts if it has been on ehu overnight, or driven recently, but if I start it then need to stop again for some reason (such as leaving something in the house and turning the van off), there isn't enough power to restart - it tries to but won't.

If it has a decent journey recently it will start without trouble. It is trickle charged through solar panel into leisure battery and a battery master into the starter battery.


I think it is my battery that is done - whilst I don't tend to make many short journeys, I do want my battery to start the vehicle more than once (i.e not get stuck at a petrol station or shop).

There was quite an interesting letter in another m/h magazine this month about airbag ECU failures caused by dud batteries. My airbag light came on in early winter and my local garage said it was knackered and needs replaced (£500-£750). I am planning to send my 'broken' ECU to a company that should be able to reset it for £30 once I have replaced the starter battery - something to be aware of if your airbag light comes on.



Any suggestions for a replacement - there is a large range of options. The current battery (I assume it is from 2012 or earlier) is 95aH.

- Lion


- Gel etc.


A Bosch S3 battery seems to be reasonably priced with a 3 year warranty - would anyone recommend this battery or a slightly more expensive S5 020 battery?


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Expert opinion on this forum is that a Varta/Bosch battery incorporating “Powerframe” technology would be an excellent choice for a motorhome’s starter-battery.


The size of a 2012 Fiat Ducato’s under-cab-floor starter-battery storage-compartment limits the dimensions of the battery that can be installed. Either of the following Varta Silver Dynamic batteries should fit






with the former suitable for Ducatos with an engine capacity of 2.3 litres and the latter (longer) battery appropriate for Ducatos with the 3.0litre motor. If your Ducato has the 2.3litre motor, you could fit the longer 110Ah battery, but the (shorter) 100Ah version should be perfectly adequate.


Both of those Varta batteries can also be obtained 'Bosch-branded', but the asking-price is usually higher, and as the Varta and Bosch batteries are identical except for their label (and both have a 5-year warranty), the Varta-branded versions seem to be the logical choice.


The Bosch equivalents are these:






An alternative approach would be to fit a Varta LFD90/Bosch L5013 ‘dual purpose’ battery






as this battery’s design characteristics make it particularly suitable for motorhomes where the vehicle may stand idle for prolonged periods of time. The dimensions are 353mm (length) x 175mm (width) x 190mm (height), so it will fit in your Ducato’s battery compartment.


(The next size up - LFD140/ L5075 - are 140Ah capacity, but much too large to go in the compartment.)

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These batteries usually last a very long time.

Before you do anything else, you must check the charging rate of the alternator.

Use a multi-meter across the jump start points under the bonnet with a multi-meter and make sure that you are getting at least 14V. It's not the ideal place to do such checks but it will give you an indication of the output.

If you see less than 14V you will need to check and/or upgrade your earth strap. More about that later.....

The air bag fault may have been caused by poor earth and might be re-settable by diagnostics once the earth situation is sorted. I have seen this a couple of times before.


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We were away this weekend and had to move the van a small distance couple of times (2 x starts) then when we went to leave, it wouldn't start (not the first time this has happened, usually when it is cold). We were jump started and drove 50 miles home.


I tried to start the van this morning just to see what happened and it started no problem, but after reading the above post I just went out and the battery was sitting at 12.3V and won't start.

I will have to put it on charge before trying to start again tomorrow, however I did a voltage test on the battery when engine was on a couple of months ago and it was over 14V at that time.


If I charge the battery the van always starts first time and if it has been out for decent drive recently it always starts first time. It seems to be if I try to start if a second time there just isn't enough power in the battery.


The van has a solar panel which only charges the leisure battery but it also has a 'battery master' that trickle charges the starter battery. (although in winter not much power is produced from a 100w solar panel!)


Would this be a symptom of an earth problem? Would it not have a problem starting even after the battery has been charged?


I am thinking either battery or alternator (or the above mentioned earth strap). It took a few tries to jump start the van yesterday - it didn't go first time, however the battery was totally flat beforehand.



Euroserv: in the Ducato the battery is inside the vehicle. Is the earth strap also inside or will it be in the engine bay?


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There is a metal earthing ‘strap’ attached to the starter-battery’s negative (-) terminal, but that’s not the strap Nick Fisher (euroserv) is referring to.


The earth-strap that can lead to electrical problems connects the vehicle’s gearbox to its chassis. The issue has been mentioned here several times in the past and in 2012 Nick advised as follows:


"There are some very frustrating electrical issues with the X250 van. We have had many instances where, completely without any warning a van has refused to start. This is normally due to degradation of the earth cable that runs from the gearbox to the chassis. For some insane reason the ECU gets it's power through this route and if there is insufficient current it just will not play ball. While driving you can sometimes see the battery warning light on and this suggests a lack of charge being returned to the battery. It never actually is though; it is the ECU flagging a problem in the only way that it knows how.


The first thing to do is to clean the joint between the earth strap and the chassis. This may help, but if you see any oxidisation on the cable it will almost certainly need replacing. Get an new one made up by an electrician and make it 6" longer. Attach it securely to the chassis point and then remove one of the screws on the gearbox end cover. Put the other crimp terminal in place and screw it down tightly using a shakeproof washer. This is the best you can do and appears to be the 'fix' recommended by Fiat to the dealers. We have had no further problems with vehicles so modified, but more than half of the vehicles we have over 2 years old have had to be repaired.”


Other forum discussions with “earth strap” in them where Nick has participated






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I guess I should just change his earth strap regardless of the battery. You said to have one made up by an electrician - would somehing like this be suitable? https://www.amazon.co.uk/gp/aw/d/B014SX66LQ/ref=mp_s_a_1_3?ie=UTF8&qid=1519203075&sr=8-3&pi=AC_SX236_SY340_FMwebp_QL65&keywords=earth+strap&dpPl=1&dpID=51S-sjaUvqL&ref=plSrch


Does it just run from the gearbox to the chassis/ does the van need to be lifted on a ramp or is it accessible from the bonnet/crawling underneath?


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Thanks Derek,


I have had a busy day!



The first thing to do is PROVE it is the earth strap. You might have a dodgy alternator but to be honest you would probably have a warning light on or at least elevated revs while idling.....


What you need is half a pair of jump leads. You only need one cable with clamps on each end but they need to be good ones; no feeble budget Halfords rubbish!


With the engine off, connect one end to the earth point at the top of the front grille and the other to the lifting eye at the rear of the top left hand side of the engine. Once this is all secure, start the engine and measure the voltage as you did before. If this additional earth is working, you should see a much better voltage which proves that with sufficient earthing, the alternator can pass on the power to not only the battery but most importantly; the engine ECU.


Assuming i was right, you need to get a new earth lead and attach it to the chassis point where the existing one is secured (straight down behind and to the right of the air filter). Leave the old one in place. It won't do any harm.

The other end goes to one of two places.

If your vehicle is a EURO4, you will have to secure it under one of the gearbox end cap screws (a lead of about 12" will do for this) but if you have a EURO5 there is an even better place to fix it. The EGR cooler tube (square aluminium, about 8" long has some curiously long screw threads exposed and Fiat have left enough room to place the loop of the earth strap over it and fit a new nut on. It's tight but it can be done and it's the better option if you can do it. You need a strap of about 18" to do this.


Earth leads need to be long enough to allow for a little engine movement and need to be guided around and away from any obvious sources of chaffing. Any excess should be looped in a 'pig tail'.


All you need (apart from the new lead) should be a 13mm socket, a ratchet and 6" extension plus a 13mm spanner and 8mm (flanged if possible) nut. If you are removing a screw from the gearbox end plate, i think it's a Torx 40. You would need to be underneath for access to the gearbox but EURO5's can be done from above. It may help to remove the air filter cover to give you some more space and remember to put some grease on those screws before you put them back.


Of course, i might have been wrong.......



By the way; NO those braided things are useless.

You need a lead made from 'welding cable' and terminated in proper crimps with 8mm holes. I believe that Halfords can make these up for you as can auto electrical specialists but i don't see any point in adding another crappy braided cable that will probably not even last as long a s the Fiat original one!


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Hammer, it does look like you had a duff battery, which is what we would expect with the Solar setup you have.


In your description of the Solar setup, you described it as having a Battery Master to 'look after the Starter battery'??

These devices are constantly monitoring both Starter and habitation battery drawing power from both. It is only a small draw but can be significant when the Winter Solar Gain is almost zero.


A battery Master is designed to steal power from the habitation battery when the Starter battery drops 0.5v below the Leusure battery.

The problem with this is that a modern Starter battery is already heavily discharged at the average 12.2v that corresponds with half a volt below a Leisure batteries fully charged 12.7v

At 12.2v the Starter battery is already undergoing long term life shortening degradation.


Have a look at the Vanbitz battttery Master Tech spec which states,

"It is designed that when the engine battery drops half a volt below the leisure battery, Battery Master automatically adjusts the charge and tops up the engine battery".


Why would you want a battery to sit at 50% or more discharged before it is 'topped up'? See the attached chart.


You can imagine how discharged the Starter battery will get if the habitation battery drops to 12.4v? if it only charges the Starter battery when there is greater than a 0.5v difference then the Starter battery will drop below 11.9v before it gets charged.


These devices do 'work', but there are much, much better ways of doing things without sacrificing battery life or capacity.


A far more efficient Solar solution would be to replace the single battery Solar Regulator (usually low quality and efficiency) with a quality dual battery solar regulator that charges both the habitation and Starter battery dynamically and directly. Without the inherent losses and inefficiencies of a battery master device. Something like the Votronic MPPT 165.



If you look at the chart from Yuasa below, you will see that an AGM 13v Starter battery would be in serious trouble if it only got 'topped up' when it was 0.5v below a conventional Habitation batteries 12.6v.

For a 13v AGM starter battery, 12.1v is over 80% DOD, just 20% power remaining.


Therefore it is very important on your existing set-up you don't fit anything other than a conventional Starter battery. I would advise against fitting a Varta Powerframe battery as these have a resting voltage near to 13v.


Euroserve is right, a Starter battery should last a long time in a commercial van that gets used every day, around 10 years is typical. But in a Motorhome the battery can stand idle for weeks at a time so discharges below the ideal for longer than ideal.

This causes them to Sulphate and degrade.


Typically, Motorhome Starter batteries on Solar can have lives half that of a commercial van that gets used every day..

I think you have actually done well to get 6 years out of the Starter battery with the setup you have.



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aandncaravan - 2018-02-23 3:59 PM


...Therefore it is very important on your existing set-up you don't fit anything other than a conventional Starter battery. I would advise against fitting a Varta Powerframe battery as these have a resting voltage near to 13v...





As ‘hammer’ has now replaced his motorhome’s starter-battery (no details provided of the make/model of battery that was purchased) it’s all rather academic - but which battery would you have recommended he fit if a Varta/Bosch “Powerframe” battery would be a poor choice?

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I fitted a Varta I1 battery. Interesting information above.. I guess in the short term it might be a good idea to ditch the battery master and give my starter battery a charge with my trickle charger every week or so to prevent damage before I sort out the solar.
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Derek Uzzell - 2018-02-23 6:55 PM


aandncaravan - 2018-02-23 3:59 PM


...Therefore it is very important on your existing set-up you don't fit anything other than a conventional Starter battery. I would advise against fitting a Varta Powerframe battery as these have a resting voltage near to 13v...





As ‘hammer’ has now replaced his motorhome’s starter-battery (no details provided of the make/model of battery that was purchased) it’s all rather academic - but which battery would you have recommended he fit if a Varta/Bosch “Powerframe” battery would be a poor choice?



Derek, the Powerframe technology battery you suggest is, IMO, the best for a Motorhomes Starter battery and habitation battery. In that price range nothing else comes close.


However, devices like the Battery Master (and many Voltage sensitive Relays) have not kept pace with changing battery technology with their higher resting voltages. So where these are fitted it changes things significantly. In Hammers case a Vanbitz Battery Master device could result in a 10 year life Varta LFD having just a couple of years life..


Where old technology electronics, like the Battery Master, is being used, best to stick with an old fashioned, conventional Starter battery, like a Hankook (but not the newer Carbon technology Hankook UMF61000 which is a very good battery but I suspect has a higher resting voltage?).

Maybe a Numax 020? It is not a great battery but has the right operational voltage range?



Even better would be to do what hammer has suggested and disconnect the battery Master and manage the Starter battery charge manually until the Solar setup can be upgraded.




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I used to use a battery master when I originally installed solar and rather than the Van-Bitz (for the reasons Allan stated) I used a CBE Battery Master just to be sure not to waste any solar energy available. It said:-



The CBE is designed to maximise the benefit of solar by sending charge at up to 4 amps to the cab battery once the hab battery has reached 13.6 volts (it only has to reach that voltage for an instant to begin transferring charge) and continues to transfer charge until the leisure battery is sensed to have dropped to 12.6 (wont in daylight due to solar input) i.e. it doesn't switch off just because it drops to 13.5V.


I figured it was a better option.


These days I'm always worried about over charging with the solar in the light of what I have read recently and wonder what those folk with the latest Powerframe Batteries and solar charging do to prevent this. It's both an interesting and complex subject.


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I notice that there was a LONG (2008 to 2016) MHFacts discussion about Van Bitz’s “Battery Master” device and CBE’s CSB2.




Also that Allan commented on such devices here in early 2017



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Thank you Derek, you certainly are a Master Searcher ! I previously took heed of Allan's comment in the second discussion you mentioned, I had never considered the difference between the apparent and actual voltage. I was pleased that I only ever used the battery master when my van was laid up/not in use, before I discarded it.


Can you locate any information on safe long term solar charging of the Powerframe LFD Batteries ?


I am still trying to figure out if I can re-program my Morningstar controller to do it satisfactorily or if the Voltronic MPPT165 can do it or if I should head in a different direction on this.

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The issues with constantly float charging a battery at 13.8v depends on the battery technology and several other factors.

An old fashioned Antimony based battery suffers Antimony poisoning and consequential high fluid loss.

Most of the issues of overcharging on non 'high' Antimony content batteries are related to corrosion of the Plates.



Most battery manufacturers specify that if a battery must be float charged, it should be at around 13.2v - 13.4v to minimise battery degradation.

Most Datacentres with big battery backup systems float charge at 13.2v

The Optimate specialist maintenance/float charger uses a mixture of 13.2v and "30 secs On/30seconds Off" technology.


Victron Energy have a charger purpose designed for long term maintenance of batteries and that has a specific 'Motorhome storage' program that monitors battery drain and charge and adapts the 13.2v charge accordingly.


The new for 2016 Schaudt Solar regulator dropped the float voltage down from 14.2v of the old unit to 13.4v for the new model.

Votronic also adopted a 13.4v float/maintenance charge for the 2016 year Solar charger range.

Rumour has it that Victron are following suit.


So clearly there is evidence that a constant 13.8v float charge that many mains chargers and Solar regulators Float/trickle/maintenance isn't ideal.



The Bosch L5/Varta LFD Powerframe range are more resistant to plate corrosion than other batteries, especially at higher voltages and temperatures. However, asking any battery to tolerate a continuous 'charge' when it isn't wanted isn't going to deliver the ideal result.


Secondly, the Powerframe range self discharge at very low levels, less than 1% a month has been quoted, compared to a budget batteries potential 13% per month. So while a budget is self discharging at a high rate, and therefore 'needs some charge', a Powerframe won't.


Thirdly some Motorhomes will have 'higher' current drain devices, like Frost protection Valves, etc. so the batteries on these Motorhomes may benefit from 'topping up' without suffering..



So depending on what mains charger/Solar regulator, battery, equipment installed, etc. could have significant impact on how one Motorhome is affected versus another. They will all be unique in the end effect on the batteries.



I would guess that a Varta/Bosch Powerframe will tolerate overcharging better than anything else, especially AGM batteries, but so many factors will affect the outcome that I would suggest you play safe and only connect Solar charging when the batteries need charging. Especially during the Summer when over charging and higher temperatures really don't go together. During the colder winter months the damage from 'overcharging' will be significantly less.


Better still adopt the Votronic MPPT 165 range as they manage float charging in a much more sophisticated way than most. Even down to better management of the Starter battery charging voltage and current..




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Allan, once more many thanks for your detailed, interesting and most useful reply, I am sure it will be of great value to many readers. I feel almost sure that there will many owners of these superb new technology batteries that are inadvertantly ruining them by overcharging, both timewise and voltage wise.


I asked Morningstar (The maker of my Solar Controller) to give me some advice on the matter and they have thus told me as follows:-


"If you needed to change the float value to a lower level you could do this by custom programming the charge controller. Below are instructions on how to go about custom programming the controller, also attached is a document that gives the definitions of the custom programmable parameters.


"Yes, the 4 stage cycle begins new every day when sunrise occurs and voltage is sensed on the Solar terminals. We have no means of taking a voltage measurement in the morning and telling the controller to just go straight to Float. Some people use the custom settings to try to mimic this somewhat. What can be done is to tell the controller to only stay in absorption for 1 Minute (Time Before Float Value). This would have the controller charge the batteries up to the absortion voltage but only stay there very briefly before going to Float. Then if you have an occassion when the batteries are discharged at night you can then use the "Float Low Battery" and "Time Before Float - Low Battery" values to extend the absortion time if the battery is discharged to a lower level the previous night. This is probably something you would want to discuss with your battery manufacturer or a system designer before implementing, so you know what may be in the best interest of the health of your particular batteries"


There are a 'raft' of parameters that can be set/reset by re-programming and I would not feel confident in setting them up myself so am considering asking if Varta/Bosch may be able to assist here if I send them the details. To re-program I need to obtain an adapter to connect the solar controller to my PC (costs about £40)


Otherwise I can simply alter the float voltage value and monitor the actual battery voltage regularly, and I am assuming I can simply disable/enable the solar charge system by switching the solar input to the controller or simply remove/replace the fuse, without causing any damage.

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Can we clarify that you are referring to two issues here with the Morningstar Solar Reg?

The first is the usual long full charge Timer interval that the Solar regulator charges at when it 'wakes up' each morning after the Solar Panel has been in darkness.

Most Solar regulators will 'wake up' in full charge mode, regardless of how charged the battery is, for a set period of time.. This can be as long as 4 hours on some regulators.

The second is the high Float voltage?


These are not an issue when the vehicle is being used and the battery needs full charge, but during long periods of being idle, to 'boost' charge a battery every day at 14.4v or whatever the voltage is, isn't ideal.

I assume you want to reduce this Timer and possibly the 'Boost' and Float voltage?


These can sometimes be reprogrammed to have both shorter time intervals and lower voltages for when the vehicle is idle, but this also results is a much reduced Charge when the van is put into use.

Continuous manual management of the settings then becomes necessary to achieve the optimum in all situations.



Most Solar regulators on the market, despite claims to the contrary, are not Motorhome specific units, but 'House' Solar based with House Solar parameters.

These House units use the premise that you will always want to gather maximum power from the Sun and throw excess power into the Grid.

Where dual 12v output is available they generally assume that both batteries are to be charged at full output.


However, on a Motorhome specific Solar regulator it assumes the Starter battery will almost always be full and the habitation battery full at least 50% of the time.


They are two quite different approaches that can lead to overcharging on many Solar installations.



The only two Motorhome specific dual battery Solar Regulators we are aware of are the Votronic MPPT range and the Schaudt MPPT LRM1218.

Both have optimised charging programs to suit Motorhome specific use with low float current and voltage for both Starter and habitation batteries.




I can't help with reprogramming the Morningstar, we would suggest that trying to program any other Solar regulator that has fundamentally different design criteria may be more hassle than it is worth, especially when the best Motorhome specific units are less than £70?.

Votronic are Motorhome specialist electronics suppliers, they understand Motorhomes and how they are used. Votronic are also Battery charging specialists, the units are very efficient.



Yes you can isolate the Solar Panel by pulling the fuse between the Panel and the Regulator without causing any damage. But as you already know, interrupting the 12v flow on the battery side should not be done without first isolating the Solar Panel from the regulator.




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Thanks again for your valuable advice, sorry I haven’t made my aims clear here.


I was not aware of the different usage characteristics of MPPT controllers (home/motorhome) when I bought my Morningstar which came from America where I was told ‘you won’t beat a Morningstar MPPT controller for motorhome use’ that was about 2008, when as far as I was aware, at the time, MPPT was a new technology (I had a PWM controller first)


I had already doubled the Battery capacity of our Transit based Camper Van by duplicating the Varta (Hobby) 957 052 000 (as fitted by Ford as an Auxiliary Battery) and wanted to make our van ‘self sufficient’ as we rarely use hook up. It has worked perfectly since then, we camp most of the year except December and January and have never been short of battery power for our requirements, and, all I have done is top up the batteries 2, sometimes 3 times a year, nothing else, just used it and parked it up. I fitted a bridge to the vehicle battery using a 5 amp circuit breaker and during lay up sometimes bridge it to keep the vehicle battery around 12.6 V.


I consider this to have been relatively low maintenance though it is a bit difficult, as the batteries are beneath the front seats, I have found ways to make it easier. The batteries have so far lasted 10 years.



I have always studied postings regarding batteries and find them very interesting, you/AandN are clearly the experts here, so having read all about the Powerframe LFD’s/Bosch’s they seem to be the ‘way to go’ for replacements, which surely I need to consider soon. All I need to determine is: The best way to charge them to suit my requirements and what to charge them with to get, hopefully, a good lifespan.


We have an on board mains powered charger fitted by Auto Sleeper (Plug in Systems CTSAN-18A)which has worked well but I have hardly used it since fitting the solar system. I assume this charger will be un-suitable for the LFD90’s as it’s float voltage is 13.6V therefore 0.2V too high for the LFD’s. I have been told that floating the LFD’s too long at 13.7V (Morningstar factory set) will shorten their lifespan probably to 12months.


So now, if I am to use the LFD90’s I have to consider:-


Re-programming the Morningstar or buying a Votronic MPP165 or another solar controller as mentioned by yourself. I don’t really mind which, and fortunately cost is not prohibitive to get the best set up with the least installation work. I just don’t know which way to go.


I must say the Morningstar MPPT Solar seems very versatile from the point of view of programming to suit (if you know what you are doing) but just to change the Float voltage looks quite easy, even to me and it can be changed to 13.4V or 13.2V even, just for the cost of the adapter and using the same charging program as default, which, I have no idea if it is comparable to the optimised Votronic program for motorhomes.


Too much information maybe is confusing me. Here is a link to the Morningstar MPPT Solar Instructions for interest:-




It would, so far appear to me that, the timings of re-charging the LFD’s is a matter that needs addressing manually if using solar charging and the float voltage needs to be considered as a matter of importance for whatever means of charging is employed. I am happy to monitor voltage and to isolate solar charge accordingly, much easier than the topping up !!


I’m not sure how to include the custom program parameters (part of) for informations but will try a picture as an example.


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Dipsticks, I did understand what you wanted to do by reprogramming the American optimised Solar regulator to compensate for it's current working, but I am not sure it is worth the effort as setting it optimally for one situation is likely to result in it needing reprogramming for another.


I have no idea how American RV's are used in the States so I don't know what an American Morningstar Solar Reg will be optimised for. Just because it works for users in the States, doesn't mean it will be optimum for UK users.

For example do they always use EHU or rarely use EHU? Do they leave Solar active all year or disable it when no charge is required? What size battery bank is typical? Do they use the vehicles more often than Europeans and maybe hire them out in between usage? Do they travel longer distances between stops relying more on the Alternator to replenish the batteries?. What battery technology is the most popular, it used to be 6volt high Antimony content batteries, but that may have changed. What electronics are installed and what is the typical charging profile, Etc.



I am not a Morningstar expert but several things seem clear.

First your battery fluid loss seems very high, indicating an issue of some sort? That may be from a failing battery, but just as likely overcharging of the batteries.


Secondly that the default Absorption 'boost' charge voltage is a very low 14.0v. This will lead to longer charging times but may have helped reduce your 'overcharging' fluid loss which may have otherwise been greater.

Setting it to the usual 14.4v will charge the batteries faster but may also result in an increase in fluid loss if the vehicle isn't used regularly?


The Float voltage of 13.7v is higher than most battery manufacturers state is ideal but remember that in this regulator when the Absorbtion charge Timer ends on the Morningstar, all the remaining charge is put in at the 'Float' voltage.

Most people think that a battery charger drops to the Float voltage once the battery is 'fully charged' but it doesn't. It usually drops to the float voltage when the 'Fast' charge timer expires. See our webpage on how a charger works : http://www.aandncaravanservices.co.uk/how-does-a-charger-work.php


So reducing the Float to 13.2v might mean that 10 hours charge is at this low voltage and only 1 hour at 'Fast' charge. On a discharged battery that might result in only partial charging versus all day at 5amps and 13.8v..


The default Timers seem to give 60 mins at 14.0v at the main 'Boost', or fast charge, when the Solar regulator first wakes up each morning.

Bear in mind that in June in the UK, that will be about 05:00 when the Solar Panel current may be well below it's peak current as the Sun is still low in the Sky.

In other words the 14.0v Boost charging takes place when the Solar Panel current availability is low. The Boost 14.0v timer probably expires just when the Solar Panel is getting into it's stride as far as current is concerned.



This is partly offset by a second timer, set at 2 hours by default, that seems to replace the usual 'Boost' timer if the battery is low - Time before Float : Low battery.



Suggest the Equalisation section is disabled as this is primarily aimed at deliberately overcharging the battery to de sulphate it. Something almost all battery manufacturers say should not be done and most experts agree does more damage than good.



So while you can alter the values, it may be a compromise for all situations.



I would suggest it would be a better option to fit a Votronic MPPT where all the values are likely to be optimum for European use.

Votronic and Schaudt are among the few companies who understand Motorhome use, Battery charging and Solar so more likely to create a Solar Charger that fits UK users better than anyone else.



We would still advise you enable Solar in the summer months only when the batteries need charging.




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Thanks again Allan for your interesting post on the solar charger subject.


Sadly, I am so sorry, as I have confused you furthermore here, the ‘parameters.jpg’ was included simply to give an idea of the parameters that can be re-programmed by the user (there are many more) (if required) It's extracted from the ‘Custom Settings Definitions Document’


The values shown are not the values in the default program I have been using for the last ten years. The actual values I have used are automatically set up as a result of setting the slider switches (just the same as is required when the Votronic is installed) as instructed in the Morningstar Instructions.




I don’t know what all the values are set at currently as I don’t have the required adapter only the values that are shown in the installation instructions as a result of the slider switch settings and jumper.


I have been using the settings for a Flooded Battery thus an Absorption voltage of 14.4 and a Float of 13.7, and, as mentioned before I fool the regulator into thinking the batteries are Gel, thus an absorption voltage of 14.0 when I am not using the van by switching a switch across the jumper terminals. (Float stays at 13.7 though) I have never used the equalization feature. I must say I still think the Morningstar re-programming can be very useful if you know, or can find out what is required or the optimum for a battery type.


Anyway I am rather naïve here as I had no idea that European Regulators as mentioned have specific values for European Motorhome use, I just thought the aim of all regulators would be to extract as much energy as possible from the available light and get it into a low battery as soon as possible until it was full, and, to achieve this to make the battery last as long as possible without damage. And to choose an appropriate model in respect of Solar Wattage and Battery/s size.


When the time comes I think I will (regretfully) pension off the Morningstar and replace it with a Voltronic MPP165 Duo. I will gain the benefit of hooking up the main engine battery but lose the facility of the Low Voltage Disconnect that the Morningstar includes. I will certainly engage and dis-engage the solar charging as required to avoid overcharging in future.


Although this thread is somewhat misplaced under the original title I’m sure Allan and certainly myself hope the information that can be extracted from it will be useful to others, as, I’m sure there will a lot of people unwittingly overcharging their batteries.


Best wishes




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I have been thinking about whether to reconnect the battery master since swapping my starter battery. After reading the above posts I wasn't going to as I figured that it doesn't really help much, particularly if the resting voltage of my starter battery is higher than that of my leisure battery.


However, when the solar panel is working the leisure battery will be higher than 13V (at the moment it is overcast and snowing lightly but the leisure battery is showing 13.6V - would it not be better to reattach it so that during spring/summer the vehicle battery would be topped up as when being charged via solar any excess energy has somewhere else to go.


In winter I could still plug in my stand alone battery charger to keep things charged.

I have just discovered that by removing the battery master, my starter battery is no longer charged when on EHU, again the starter battery is being charged via the battery master.


Thanks for the advice so far.



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hammer - 2018-02-26 11:38 AM


I have been thinking about whether to reconnect the battery master since swapping my starter battery. After reading the above posts I wasn't going to as I figured that it doesn't really help much, particularly if the resting voltage of my starter battery is higher than that of my leisure battery.


However, when the solar panel is working the leisure battery will be higher than 13V (at the moment it is overcast and snowing lightly but the leisure battery is showing 13.6V - would it not be better to reattach it so that during spring/summer the vehicle battery would be topped up as when being charged via solar any excess energy has somewhere else to go.


In winter I could still plug in my stand alone battery charger to keep things charged.

I have just discovered that by removing the battery master, my starter battery is no longer charged when on EHU, again the starter battery is being charged via the battery master.


Thanks for the advice so far.



If you're going to fit a Votronic regulator, it automatically diverts excess current up to 1Amp to the starter battery. I only have a single 100W panel and because of where my van is parked right next to the house it is in shade for most of the day until mid afternoon, but I have found the Votronic controller capable of keeping my vehicle battery charged most of the time even so.

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