Leisure Battery

I have the standard AS set up of 100w solar and 100ah Lithium Iron leisure battery together with a compressor fridge which pulls around 4 amps for around 9/10 hours per 24 hours so that's around 2 amp per hour average with an additional  system parasitic draw of 0.3 amps when the fridge is off. It appears from the paperwork that the BMS in the battery will shut the battery down around just over 11volts or so which is a bit of a shock. Solar is around 4.5 amps when the sun shines to around 2 amps later in the day down to 0.5amps when cloudy.

The question is it looks like with no hook up even after just 36 hours unless it's a really sunny day I will have no 12v supply as it will shut down even with no TV, no rectifier and only a few internal led lights on?

Freeride wrote:I have the standard AS set up of 100w solar and 100ah Lithium Iron leisure battery together with a compressor fridge which pulls around 4 amps for around 9/10 hours per 24 hours so that's around 2 amp per hour average with an additional  system parasitic draw of 0.3 amps when the fridge is off. It appears from the paperwork that the BMS in the battery will shut the battery down around just over 11volts or so which is a bit of a shock. Solar is around 4.5 amps when the sun shines to around 2 amps later in the day down to 0.5amps when cloudy.

The question is it looks like with no hook up even after just 36 hours unless it's a really sunny day I will have no 12v supply as it will shut down even with no TV, no rectifier and only a few internal led lights on?

If the fridge draws on average 2A, over 24 hours it will consume 48Ah
If the parasitic load is on average 0.3A, over 24 hours it will consume 7.2Ah
Total consumption over 24 hours - 48Ah + 7.2Ah = 55.2Ah

The real unknown is the solar charge but if on average a current of 2A flows for 12 hours, over 24 hours it will generate 24Ah

So, over each 24 hour period the leisure battery will lose 55.2Ah - 24Ah = 31.2Ah.  If the Li-Ion battery is not allowed to drop below 20% SOC and it is fully charged to start with, it will have 80Ah of useable charge which will last 80 divided by 31.2 = 2.56 days.

Others who have a similar setup to yours will comment on how realistic the figures are which exclude any charge from the engine alternator.

Freeride wrote:I have the standard AS set up of 100w solar and 100ah Lithium Iron leisure battery together with a compressor fridge which pulls around 4 amps for around 9/10 hours per 24 hours so that's around 2 amp per hour average with an additional  system parasitic draw of 0.3 amps when the fridge is off. It appears from the paperwork that the BMS in the battery will shut the battery down around just over 11volts or so which is a bit of a shock. Solar is around 4.5 amps when the sun shines to around 2 amps later in the day down to 0.5amps when cloudy.

The question is it looks like with no hook up even after just 36 hours unless it's a really sunny day I will have no 12v supply as it will shut down even with no TV, no rectifier and only a few internal led lights on?

Quite possibly. I am afraid that in my personal opinion AS design these vans to just make it from one EHU to the next on a daily basis. You probably have a B2B charger, but perhaps only 20 amps from what I have read here, so that may not be an awful lot of help particularly if you want to stay for more than one day in one place and don’t drive for more than an hour or so. 100 watts of solar is little more than a maintenance charge, just a top up, certainly if reliant on Sargent elechronics.

With respect I suspect that Caraman’s calcs. are rather optimistic and exclude TV, lights, water pump, boiler, phone charging etc. The stark truth in my possibly jaundiced opinion (I come from the marine trade where the billionaires expect their chip fryers to be on 24/7) is that your van will run for not much more than 24 hours on fairly minimal loads. That is fine if you use campsites with ehu, but if you want to camp without ehu you will need a fairly comprehensive upgrade to your electrical system, to include enhanced battery capacity, enhanced solar & enhanced engine/B2B charging.

Bargee is quite right.  As I thought you had excluded other habitation loads, for comparative purposes I did likewise.  But it's not realistic to do so.

We have near identical loads, especially the compressor fridge   
130w solar, dual battery pwm controller.
In normal, not necessarily sunny conditions we are energy self sufficient indefinitely.
Gas for cooking, hot water and heating of course.
I suggest, switch everything  which can be, off, disconnect solar or do this when dark, and measure the current the battery is supplying, clearly, it should be zero. If not, there is a parasitic load somewhere

IanH wrote:We have near identical loads, especially the compressor fridge   
130w solar, dual battery pwm controller.
In normal, not necessarily sunny conditions we are energy self sufficient indefinitely.
Gas for cooking, hot water and heating of course.
I suggest, switch everything  which can be, off, disconnect solar or do this when dark, and measure the current the battery is supplying, clearly, it should be zero. If not, there is a parasitic load somewhere

But as I recall Ian you have a better charging system, viz. dumb alternator and heavy duty split charge relay, also possibly better solar regulator direct to batteries. I suspect Freeride has smart alternator and only 20 amp B2B, so the batteries might not be quite so well charged at the point of parking up if not many miles driven. Solar doesn’t sound that effective either.

Ian, I suspect the 12V habitation load of a newer motorhome is more than yours.  Modern heating systems draw quite a bit.  If the oven or grill is used for any length of time, its cooling fan comes on.  The kitchen has a fan.  The vehicle electrics, tracker and alarm if fitted take a bit and the EC700 which you don't have has a constant load which the OP has estimated at 0.3A.  It all adds up and that's without the compressor fridge's significant drain.  I suspect the compressor fridge is only suitable for those who do a lot of driving and have a decent solar panel set up.  It wouldn't work for me for example as we typically spend 4 days on a pitch without driving anywhere, we only have a 80W panel and I suspect our 90Ah leisure battery only has a useable capacity of about 40 Ah.

Thank you for your most informative replies.
My old MH 100w solar and 7 year old leisure GSM battery with a gas fridge could easily cope with 4 days with no hook up at a motorsport event or a "town festival". With no TV as that was 240 and no microwave of course. No tracker or Wi Fi fitted. No worries at all just a split solar charger that I changed to 80/20 in favor of the leisure battery.

Now it appears from experience with this van unless it is really sunny all day I'm not going to cope for any length of time as the "battery alert" comes on. Bearing in mind  we didn't use  the TV as it's 12v, not used the gas oven so no fan, limited lights on, the tracker is on, Wi Fi is on the TV Ariel was on but I could switch that off but that can't a big draw? Phone charging someone raised is a good point as  when plugged in this was 0.3/0.4 amps.
The big draw is the fridge the water pump is 3/4amps but not on for long. Water heating is gas of course.

So the solution must be another panel and possibly another 100ah battery as I don't want to spend all my time worrying about the 12 volt battery? We are not wild campers but we do have a number of long weekends away with no hook up when toilets and showers are provided mainly motorsport.

The other question is how long do you need the engine on at idle to charge the LB back up as it doesn't seem too long although not very environmentally friendly or is that how long is a piece of string?

If you are mostly travelling to events directly from home then it may be that you can leave home with fully charged batteries (from the mains) and then you only need solar to keep them topped up, presuming summer events. I upgraded the solar on my Kingham last spring.

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As I recall I was seeing 20+ amps in the spring from these Renogy panels and Victron controller. Works really well. See also recent threads on TV aerials.

With respect to running your engine to charge batteries that is not a good idea, certainly if you are starting from cold. Diesels want to work, and are best warmed up quickly. Ticking over cold on a very light charge rate (see below) is not good for the engine. Automotive alternators are regulated to cut back the charge rate fairly rapidly, so prolonged running will be subject to the laws of diminishing returns. My alternator shoves out as I recall 90 amps + on start up, but this rapidly cuts back (within a few minutes) to about 40 amps, which then remains steady for quite a while, so the LB charge is good over say two + hours driving. In your case (presumed with 20 amp B2B) none of that applies because your B2B will only ever charge at 20 amps, and will shut down once you stop the engine and the VB voltage drops below 13.3. So to put back say 80 amps into a max. discharged 100 AH lithium will take about four hours.

I'm on a trip now and have just moved site - a little over 45 miles and 1 hour driving plus a supermarket stop on the way.  Over 7 days this is the only mileage I will do.  Although I don't have your setup Freeride or a compressor fridge, I am sure that if you aspire to do the same without EHU support at this time of year or later, as a minimum you will need to fit a better solar regulator which many of us have done and increase your solar panel area.  The only other option is lots of driving and improved alternator charging which Bargee has alluded to.  BTW I totally agree with Bargee, static engine running is definitely not the way to go.  It will wear out your engine and cause unwelcome noise and pollution on site.

Many thanks but I do think I've made a step backwards on the "capacity" front! It is looking like the only upgrade I can do for a quick fix is add one more 100w panel which will allow me to keep the original solar controller(max 200w) as if I'm not careful I will ruin any possible future warranty claims??

I’m afraid my impression from what I read is that there could be overall battery charging issues when a modern eco friendly EU6 van with smart charging is converted to a motorhome. I suspect (but only an impression : I have no personal experience) that the overall charging output from the vehicle alternator is much choked down by the software controls applied, and I don’t think there is any way round this. So even if a larger B2B is fitted I do wonder whether there will be enough output “allowed” from the alternator to feed it. I would be happy to be corrected.

Improved solar would seem to be the way to go. If you would be employing somebody to install this for you then surely Autosleepers might do the job, and then you could hardly be affecting your warranty. You would need advice on the specification, for example to make sure that good components are used and that the charge output does go straight to the batteries, not via the Sargent system, which I suspect is limited to 20 amps anyway for circuitry and heat reasons, but I am sure this forum would put you straight on that.

I think you are right about the warranty though. One of the possible issues that you might well face and might need your warranty for is the electronics, so you don’t want to be messing with any part of the related electrical system whilst your warranty remains valid, unless A/S agree.

Ah! Now see your vehicle age.
It is therefore likely that your solar is connected via your Sargent system....
If so your performance will be greatly improved by a dual battery controller connected to each battery directly with a 10A fuse on the battery +very terminal.

Freeride - I would do the solar first and see how you get on with that before increasing your battery storage.  If you get A-S to do it to maintain the warranty, try and get them to do what IanH has said and fit a suitably matched solar regulator that bypasses the EC700.  EC700 smart solar charging is not that smart.  Its better IMO to fit a regulator that charges the LB directly with a trickle charge going to the VB.  When you arrive on site, the VB should be fully charged.  Providing you don't leave the cab lights or cab radio on, all the VB should need is a trickle charge.  The regulator I and quite a few other have fitted is the German made Votronic MPPT.  You will need a higher capacity one than mine which includes a cooling fan. The only downside of bypassing the EC700 is that the EC700 CP will always show nil solar charge but there are many upsides.  Also get them to use the high gauge cables that Votronic recommends from the solar panels to the regulator and the regulator to the LB.

Do Votronic do a Bluetooth regulator with App? The regulator needs to be as close to the battery(s) as possible to minimise DC voltage drop at the regulated lower voltage. That can make it difficult to mount the unit in a visible area, hence Bluetooth and an app can be useful. I prefer Victron stuff , and in your case would consider a Victron regulator with Bluetooth. That will be single output so I would fit a battery master to keep the VB topped up.

I’m not sure AS have any big cabling! If they do they didn’t use it in my van. Go as big as possible on the cable sizing, especially from regulator to LB.

I don’t think they do an App but an optional remote display can be bought.  I fitted my Votronic where the previous Sargent unit was which means I can’t see the LED lights on it and didn’t bother with the display.  Others said it wasn’t worthwhile.  I fitted some additional leads to a small terminal block that allows me to monitor the input voltage and outputs to both batteries with a digital meter. I used to do this quite often particularly when the EC700 was shutdown but now it’s much more fit and forget.  The Victron way you have described is the alternative way of doing it.  I don’t know which is cheaper.  My Votronic behaves like a battery master with the VB trickle voltage tracking the LB charging voltage but a little bit less.  It even does this at night when there is no solar charge with the mains charger on.

I believe there is a unit/app which connects to the Votronic solar controller but I didn’t investigate it much after I saw the cost, it was more than the controller itself!!

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Going back to my old van as above it had one 100w solar and a dual controller this was wired directly to the LB. Later I wired the VB into the other side of the controller and set it around 80%VB. 20%LB over the winter as the only loss was the vehicle locking no alarm or tracker. That would survive easily  5 weeks or so in the dead of winter when we were away start up straight away.
Now I think I will add another panel with a separate controller for the LB and wire directly to the LB hopefully this will not void any warranties? I need to speak firstly to Mr Sargent and AS to see how I stand however this may need another roof penetration or I may get them to do the work.
As I stated above we went away for 3/4 days in the summer with no hook up used lights, 12v TV, Wi Fi, charged phones no oven cooking. It was very sunny, in a school car park with no shade and I never gave the LB another thought at all. But our last trip in early September was  dull and overcast that's when the alarm triggered all checked out OK by the dealer. But accuracy aside of the readings the solar panel was struggling however  fine when the sun was out but that was sporadic.

If it was me (and it was me when my van was still in warranty) I would just bite the bullet and do the ‘solar mod’ now with the existing panel also going to a new controller wired direct to the battery/batteries. The new panel can be connected with the existing. That setup will work great as many on here have proved.
As far as the warranty is concerned, all you are doing is disconnecting the existing panel from the Sargent which is usually a plug connector.

My impression was that a new separate panel direct wired to the LB was the pragmatic immediate solution, but I didn't want to be the first to suggest it!

One of the biggest warranty issues with these vans (and topics on this forum) seems to be the Sargent installation. When mine failed just after I bought the van (and before I could even use it) the causation was supposedly spikes from the Sargent solar controller. These apparently damaged something and the entire Sargent system shut down completely. Luckily we were still in the drive and not out on top of a mountain. That was fixed under warranty but I never trusted the unit after that.

So I do feel that any solar modifications need at least to be referred to AS for approval, and perhaps carried out by them if you value the warranty. They may well specify Sargent components, which do not always seem to be the best available. They may not agree to wiring direct to the LB. But I would have thought that if the new solar system was wired directly to the LB through a good quality controller such as Victron, and not connected through the EC700 in any way, then the possibility of spikes would be minimal, certainly with LA batteries. LA batteries will act as a buffer against spikes but I wouldn't know about your lithium. 

There are perhaps some deeper considerations though if you will be making a habit of staying several days in venues where no EHU is available. The simple addition of another small panel may not prove enough long term, or of course it may, but I would be looking at the alternatives to improve the system as much as feasible in one hit.

Some points arising from my own solar improvements on my 2019 Kingham:

1.  The 175 watt Renogy mono panel fits perfectly where the existing panel is at the front. It just fits between the roof rails and is the biggest "quality" panel that I could source that would fit.

2.   The same size panel also fits neatly between the middle and rear skylights if you first remove and blank off the TV antenna. You may or may not use that antenna and/or agree with the negative comments in a recent thread on these but I was more than happy to get rid of that antenna and use the space for a second 175 watt panel.

3.   In my opinion the original Sargent wiring to our 80/100 watt (?) panel was of dubious quality and size, and certainly not sufficient for any larger panel output. Connections were also childishly poor which to me made the whole system suspect, visible and invisible. Cable sizing and quality is paramount when dealing with low voltages; the bigger the better. I wired the two new panels in series with well sized (6 sq.mm) cabling going down through a new inlet sited above the wardrobe, so easy to access now and in the future. It was impossible to use the original input fitting over the cab.

The additional electrical energy demand of a compressor fridge is clearly a factor that AS have not properly considered. Personally I think that the advantages outweigh the disadvantages, but I would be putting as much solar on that roof as possible, particularly if I was trying to park off-grid for days on end on open event fields where the fridge will be working hard (but as will be the solar).

Dbvwt wrote:If it was me (and it was me when my van was still in warranty) I would just bite the bullet and do the ‘solar mod’ now with the existing panel also going to a new controller wired direct to the battery/batteries. The new panel can be connected with the existing. That setup will work great as many on here have proved.
As far as the warranty is concerned, all you are doing is disconnecting the existing panel from the Sargent which is usually a plug connector.

I think Dbvwt is right.  If all you are doing is unplugging the existing solar panel from the EC700 and then routing the output to a different regulator connected directly to the battery(s) it shouldn't invalidate the warranty - unless lifting out the EC700 to access the regulator invalidates the warranty which I don't think is the case.  Research tells me that if 2 or more panels are to be connected to the same regulator input, whether in parallel or series, each panel should ideally be the same with the same voltage output.  So that means replacing the 100W panel with say 2 x 175W panels like Bargee giving 350W, or, adding an identical 100W panel giving 200W, or, 2 identical 100W panels if they will fit giving 300W.  I also understand that an additional panel of any size or voltage can be added if it is connected to its own regulator and then 2 regulators are connected to the same battery.  How that works is beyond me but apparently it does.

Looking at my photo again I think you might get 2x 100 watt panels on the rear area of roof without removing the TV antenna. One across the roof by the antenna and one fore & aft to the near side of the over-bed skylight. If that is the case you could leave the present Sargent installation as it is for the present and wire the two new panels in series through a single channel controller (e.g. Victron) to the LB. I did look at all these possibilities when I planned my install but the original panel was doing nothing so I plumped for the 2 x 175 watt identical panels, and the antenna was also useless so that was coming off anyway.

You might get some shadowing from the antenna though.

The Bargee wrote:Looking at my photo again I think you might get 2x 100 watt panels on the rear area of roof without removing the TV antenna. One across the roof by the antenna and one fore & aft to the near side of the over-bed skylight. If that is the case you could leave the present Sargent installation as it is for the present and wire the two new panels in series through a single channel controller (e.g. Victron) to the LB. I did look at all these possibilities when I planned my install but the original panel was doing nothing so I plumped for the 2 x 175 watt identical panels, and the antenna was also useless so that was coming off anyway.

You might get some shadowing from the antenna though.

I have phoned Mr Sargent a couple of times and their response/advice mirrored what has been posted.
With a compressor fridge the original set up of 100w solar and 100ah LB will struggle for any length of time with no hook up unless you are in Spain?  The advised solution is to add more solar through a separate controller and wire directly to the LB. The existing Sargent Controller install will only take a total of 150w anyway.
As advised on here the solar input on the existing  Sargent display will obviously be incorrect as any new solar will not show up when wired directly to the LB. I'm assuming that the LB voltage read on the main display will show the actual battery voltage which will include the  additional from the new solar wired directly to the LB??
From the post above:- The Bargee as I understand I should be able to install two additional 100w panels  on the roof to the rear albeit with a little TV area shadowing with presumably another hole in the roof to get the cables down through the wardrobe?? There is the possibility of unplugging the existing solar and redirecting that to the new stand alone controller. 
To be looked at is how I do THE WORKS to retain any warranties the easy option is to let the supplying dealer do the install with maybe an additional roof penetration? later I can add a second battery as that looks to be like a plug and play job with a ready made harness.

You have a solution.  Fit two new 100W panels identical to the one you already have.  If there is any chance of unequal shading between the panels, as there will be due to the TV antenna, connect them in parallel with the highest gauge cabling possible to a new MPPT regulator fitted as close to the LB as possible and connected to it with the highest gauge cable possible.  The new regulator must be rated for at least 300W.  Unplug the existing 100W panel from Sargent's 150W poor quality PWM regulator (the same as I had) which can remain connected to the EC700, or, put in the bin which is all its any good for.  The effect on the EC700 will be no different to covering up the 100W panel and should not have any impact on the EC700 warranty.  Cut the feeble plug off the existing solar panel feed and splice a high gauge cable to the new MPPT regulator.  All this will vastly improve your off-grid performance.  In the longer term you could double your LB storage which I am sure in the right conditions will allow an inverter to be used to power mains appliances intermittently.   

Your choice of MPPT regulator is the dual battery Votronic or Epever but the latter is rather large, or, the single battery Victron with a battery master between the LB and VB.  The Victron way might be best if you want to see what's going on through its App.  Although the EC700 CP and AS Monitor will show nil solar charge, they will still show the LB and VB voltages and, whether the EC700 is shutdown or not, AS Monitor will still give historic snapshots of the LB voltage.