Leisure Battery

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.

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.

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 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.

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 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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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).

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.