Solar charging engine battery

[chenderson1965]

Hi All,

I have a 2012 N&B Arto 79R. We bought it second hand in September and it was very highly specced with a number of mods added by the last owners - levelling jacks, hab air con, two TVs, Gaslow etc.

The mods include a 100w (I think) solar system on the roof. This seemed to work OK when we took it for it's first trip, although we were driving most days so hab and vehicle batteries were being topped up that way too.

It's stored away from my house. It's parked next to a tall building, on it's East side - with another tall building a short way to the west, so should get good sun from late morning to early afternoon. There's nowhere to hook it up to mains electric. I do understand that sunshine hours and intensity in winter are much lower so the yield from the panels will be much less.

I know that the alarm, tracker etc will use a little charge so I'm going regularly to give it a good run (45 mins at least but until I can see hab and vehicle batteries are both fully charged) to top up the batteries. I'm finding that the vehicle battery is going down to 12.2-12.4v in 2 weeks, which means fortnightly trips to take it out and this is becoming a bit of a pain. I've had the vehicle battery properly tested and they tell me that it's fine. The Hab batteries (2x80aH) do drift a little but are usually over 12.5/12.6v. I'm happy to go over to drive it every month (which is probably good for the engine/tyres etc anyway) but every two weeks is annoying.

Before I invest money to solve the problem (maybe Efoy or adding more solar panels), I want to test whether the solar is charging the vehicle battery as well as the hab batteries. I have a multimeter but don't know how to test whether the solar panels are charging and, if so, which batteries the charge is going to.

I've attached the best pics I have of the charger unit because I know that tool can have an impact on charging efficiency.

Could someone guide me please?

Thanks

Chris

 

[WillH]

I am certainly no expert but the first picture showing showing your solar charge controller indicates only one battery connected to the controller, probably the leisure battery. If this is the case then your chassis battery is getting no charge.

There are many other controllers available that will charge both your batteries on a selective proportion, i.e. 50/50% or 90/10%. (this is what I have on my van).

 

[Jev88]

Search battery master or battery to battery on the forum. Simple device that will skim excess Leisure battery power to engine battery.

 

[eddie]

Hi buy one of these and it will do exactly what you want.

Battery Master

 

[funflair]

Being a N+B it will have CBE electrics system as standard and this will most likely include a CSB2 that allows charging of the vehicle battery when you are on hook up, it switched to charge the vehicle battery when the leisure bank reaches 13.6 or 13.8 volts, it is similar to vanbitz battery master BUT also different in one important aspect and that is that on a solar system of limited capacity or in poor weather the habitation battery bank might only reach 13.5volts so nothing goes into your starter, with the VB battery master it works on a difference of something like .65 volt between the two batteries so it kicks in and does what it does. These two devices sit side by side quite nicely so no need to worry about disconnecting anything, we had exactly this on our Flair plus the EFOY as there was a roof where it was in store, if you had the EFOY you would still need the "battery master" for it to work well.

If you can get a bit more solar up and a MPPT if not already that would help as well.

Martin

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[autorouter]

It is a fact that a 12V lead-acid battery of any type (wet, AGM, Gel etc) can never give out more than 13.6V. So if you measure a voltage at the battery terminals of more than 13.6V, something must be charging it.

When a battery is disconnected from a charger, its voltage will slowly drop over an hour or so from about 13.5V to its 'resting voltage', which to some extent indicates its charge state. 12.7 to 12.9 is fully charged, depending in the battery type. There are charts showing charge percentage against battery resting voltage, very similar but slightly different for each battery type.

So reading the battery voltages with panels in full sun and at night will tell you if they are being charged. A 100 watt panel in sunlight for a good part of the day should be plenty to keep both batteries charged. I use a 2.5 watt panel inside the windscreen to keep a car battery charged while away from home.

If as I suspect the starter battery is not being charged from the solar panel, there are two solutions.

A BatteryMaster connects between the leisure battery and starter battery. If the starter battery voltage drops more than about half a volt below the leisure battery voltage, it will send a trickle charge to top up the starter battery. Even if you run the leisure battery flat, no charge will go from starter to leisure battery via the BatteryMaster. Simple, fit and forget.

Alternatively you could upgrade your solar controller, which I think is a single output type, to a dual-output type, which will split the solar power between the two batteries, 10/90% for example. You could upgrade to an MPPT type at the same time, which gives a bit more output in cloudy conditions than the existing PWM type.

 

[chenderson1965]

Hi buy one of these and it will do exactly what you want.

Battery Master

Thanks. I'll almost certainly order the Battery Master.

Is it worth also ordering an MPPT charger unit? Do you stock them and how easy would that be to fit alongside the Battery Master? (I'm a novice to that sort of thing).

Cheers.

Chris

 

[chenderson1965]

Being a N+B it will have CBE electrics system as standard and this will most likely include a CSB2 that allows charging of the vehicle battery when you are on hook up, it switched to charge the vehicle battery when the leisure bank reaches 13.6 or 13.8 volts, it is similar to vanbitz battery master BUT also different in one important aspect and that is that on a solar system of limited capacity or in poor weather the habitation battery bank might only reach 13.5volts so nothing goes into your starter, with the VB battery master it works on a difference of something like .65 volt between the two batteries so it kicks in and does what it does. These two devices sit side by side quite nicely so no need to worry about disconnecting anything, we had exactly this on our Flair plus the EFOY as there was a roof where it was in store, if you had the EFOY you would still need the "battery master" for it to work well.

If you can get a bit more solar up and a MPPT if not already that would help as well.

Martin

Thanks Martin. Super helpful (as ever).

 

[eddie]

Thanks. I'll almost certainly order the Battery Master.

Is it worth also ordering an MPPT charger unit? Do you stock them and how easy would that be to fit alongside the Battery Master? (I'm a novice to that sort of thing).

Cheers.

Chris

The link to buy the Battery Master is the Motorhome Fun shop

We do stock MPPT Regulators, but to be honest we are an installation company and don't really do mail order so you would be best off buying online,

We have tested loads of MPPT regulators side by side and the output variation is enormous so we recommend the Victron BlueSolar MPPT 75/15 15A Solar Charge Controller for Solar Panels up to 220W which is only £87.99 on Amazon for example

You simply swap the wires over one by one so very straight forward

 

[pappajohn]

Nothing wrong with your engine battery.
Alarm, radio memory, immobiliser and some engine electronics will draw a current with ignition off/key rwmoved and what you state is about right over a 2 to 3 week period.

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[chenderson1965]

The link to buy the Battery Master is the Motorhome Fun shop

We do stock MPPT Regulators, but to be honest we are an installation company and don't really do mail order so you would be best off buying online,

We have tested loads of MPPT regulators side by side and the output variation is enormous so we recommend the Victron BlueSolar MPPT 75/15 15A Solar Charge Controller for Solar Panels up to 220W which is only £87.99 on Amazon for example

You simply swap the wires over one by one so very straight forward

Thanks Eddie. I want to buy a controller which will allow me to add more panels. Could I trouble you to a couple of further questions?
- Is there a Victron model which will do greater capacity - say 300w?
- If you add extra panels do you need a model with extra inputs?
- I think there's a model which has bluetooth control so you can adjust how the charging power is distributed between the vehicle and leisure batteries. Which should I look for to be able to do this?

Thanks so much

Chris

 

[eddie]

Thanks Eddie. I want to buy a controller which will allow me to add more panels. Could I trouble you to a couple of further questions?
- Is there a Victron model which will do greater capacity - say 300w?
- If you add extra panels do you need a model with extra inputs?
- I think there's a model which has bluetooth control so you can adjust how the charging power is distributed between the vehicle and leisure batteries. Which should I look for to be able to do this?

Thanks so much

Chris

There is a whole raft of Victron Solar Controllers to suit pretty much every permutation

Solar Charge Controllers - Victron Energy

Get the highest attainable efficiency from sunlight, even if it is limited, with the solar charge controllers from Victron Energy. Find a dealer nearby.

www.victronenergy.com

I have three 150W solar panels on my camper roof and I decided to use three matching Victron regulators, this way if there is any issue with an individual panel or regulator I am only loosing a third of my solar capacity until I can rectify the issue.

It is possible to install the panels in parallel so using one larger regulator, which is fine, I prefer the built in redundancy of separates

Or you can wire the panels in series on the roof, which again will allow you to use a single regulator at a higher input voltage. The downside of this is that shading will have an effect, but I accept that this problem is of less consequence on better quality panels but a potential to think about none the less, again, which is why I favour the way that we do it.

Yes there are Bluetooth variants that does give you a lot more options, but I would always go for a good solar set up and a Battery Master than a dual regulator that will only charge the engine battery when its light so potentially not charge for longer periods over the Winter months, whereas the Battery Master will keep the engine battery topped up using the leisure battery, allowing the panel to replenish the leisure battery when the grey cloudy skies have gone!

 

[chenderson1965]

There is a whole raft of Victron Solar Controllers to suit pretty much every permutation

Solar Charge Controllers - Victron Energy

Get the highest attainable efficiency from sunlight, even if it is limited, with the solar charge controllers from Victron Energy. Find a dealer nearby.

www.victronenergy.com

I have three 150W solar panels on my camper roof and I decided to use three matching Victron regulators, this way if there is any issue with an individual panel or regulator I am only loosing a third of my solar capacity until I can rectify the issue.

It is possible to install the panels in parallel so using one larger regulator, which is fine, I prefer the built in redundancy of separates

Or you can wire the panels in series on the roof, which again will allow you to use a single regulator at a higher input voltage. The downside of this is that shading will have an effect, but I accept that this problem is of less consequence on better quality panels but a potential to think about none the less, again, which is why I favour the way that we do it.

Yes there are Bluetooth variants that does give you a lot more options, but I would always go for a good solar set up and a Battery Master than a dual regulator that will only charge the engine battery when its light so potentially not charge for longer periods over the Winter months, whereas the Battery Master will keep the engine battery topped up using the leisure battery, allowing the panel to replenish the leisure battery when the grey cloudy skies have gone!

Thanks Eddie. Just one more question. On the Battery Master, what is the threshold differential between the voltage on the leisure and vehicle batteries at which cross charging begins?

 

[DBK]

Just to chuck in my tuppence worth. I replaced a cheap but not very cheerful controller with a Victron 75/15 controller and it worked fine for about 3 years until it failed in Spain. I found a local supplier and had a replacement unit delivered to the campsite we were on in a couple of days. Far from putting me off Victron my experience did the opposite. They have a five year warranty and a Europe wide distribution network so you should be fine if you run into troubles, which are rare I think and I was just unlucky.

I already had a battery master and it has performed faultlessly for the last 7 years. My two panels, making 190W, are wired in series. Victron recommend series wiring. The installed wiring when I added the second panel I felt was a bit thin for nearly 200W but series wiring means higher voltage and lower current so minimizing the effect of the thin wires.

 

[ManTheVan]

I’ve had a Victron Smartsolar 75/15 on the boat and now have it in the MH. The difference is very noticeable and you can see the stats and live performance of the panel using the Bluetooth connection.

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[Nasher]

Another vote for the Battery Master - fit & forget, it just works

 

[funflair]

Thanks Eddie. Just one more question. On the Battery Master, what is the threshold differential between the voltage on the leisure and vehicle batteries at which cross charging begins?

I think Eddie is having a day off so I will jump in I believe that it’s 0.65v starter lower than habitation.

And just to add, on your Arto you should find battery B1 B2 and -ve terminals right next to each other in one of the CBE boxes so fitting couldn’t be easier.

Martin

 

[Richard n Ann]

I fitted a dual output mppt controller (Votronic duo 250) it sends up to 1 amp to the starter battery. So if you're changing the controller for an mppt type you might as well fit a dual one and save yourself £59.99

 

[jongood]

Thanks. I'll almost certainly order the Battery Master.

Is it worth also ordering an MPPT charger unit? Do you stock them and how easy would that be to fit alongside the Battery Master? (I'm a novice to that sort of thing).

Cheers.

Chris

Sorry havent read the whole post, but Ive got a CSB2 on my Arto, works a treat and really cheap.

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=323168547938

 

[funflair]

Sorry havent read the whole post, but Ive got a CSB2 on my Arto, works a treat and really cheap.

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=323168547938

You need to read the first post Jon the CSB2 needs minimum 13.6v before it kicks in a you don't always get this from solar alone. We had both on the Flair

Martin

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[jongood]

You need to read the first post Jon the CSB2 needs minimum 13.6v before it kicks in a you don't always get this from solar alone. We had both on the Flair

Martin

Ours works ok Martin as long as its outside.

 

[jongood]

You need to read the first post Jon the CSB2 needs minimum 13.6v before it kicks in a you don't always get this from solar alone. We had both on the Flair

Martin

Actually I'm having a rethink on this. I'm basing ours working fine on being parked up off grid for a few days at a time. I suppose a prolonged period of no sun could mean that it wouldnt supply enough to maintain. Sorry Martin.

 

[funflair]

Actually I'm having a rethink on this. I'm basing ours working fine on being parked up off grid for a few days at a time. I suppose a prolonged period of no sun could mean that it wouldnt supply enough to maintain. Sorry Martin.

That’s what we found Jon and if you are using the van in one place or a week or so you are constantly using power from your habitation stopping it reaching 13.6v and using the radio on Starter battery depletes that.

Martin