What solar controller?

[funflair]

Well this morning has shown our batteries are dying. Yesterday we were fully charged on EHU, then drove for 4 hours. Batteries reading 14.1 while driving, solar controller turned itself off, batteries at 13.8 once parked for the night. This morning they are at 11.8v, heating cutting out when we turn on a tap...
300Ah batteries shouldn't run out in just one night when our load is maximum 5A an hour!

Could be just one battery pulling the whole bank down, but if they are of an indeterminate age a fresh start might be in order, big batteries are heavy to shift about.

Have you looked at your old batteries to see if they are open or sealed, you would not be the first person to let open ones go dry.

Martin

 

[Richard n Ann]

And on a grey day? possibly 1 amp, thats where extra capacity comes in.

Martin

Yeah, we are quite low users though. We get 2 or 3 amps if the clouds are white, and that's usually enough.
Our biggest drain will be the TV. Ann tries to watch in bed but falls asleep. I wake up hours later and switch it off

 

[Lenny HB]

With the Hymer you will need low profile batteries to fit the locker so limited to the 90a/h so I would go for 3 of them, you can never have enough battery power or solar.
For your use I would try to get another panel on the roof and a better charger like the Votronic would improve things.

I have 3 X 80a/h gel batteries and just bought a Votronic controller to upgrade my system and a 3rd 100w panel. Waiting for it to get warmer to fit the panel before we are off to Spain next month, too cold for the adhesive at the moment.

 

[Lenny HB]

Another point as you have flooded batteries has the EBL been changed over to the correct setting (original fitment would have been Gel or AGM bateries), if it is set to Gel that will shorten the life of flooded batteries and there is a danger of them gassing off.

 

[Randommoose]

Hi,
Sorry for the delay in replying, didn't have internet for a day and then had a long drive back home. So now we are in the UK, have rung some battery places and got some prices. Came to open the locker and it is a bit more complicated than expected.

It turns out we have two Numax batteries and a Lion battery. The batteries need to come out really to measure the locker as the Varta batteries are bigger (35cm instead of 30cm) so we need to check they will fit before buying them. But I don't know what order to disconnect all the wiring in.

What I know is connected:
12V system
Solar
Satellite, TV, some other 12V that doesn't run through the EBL (couple of lights and a socket I think)

I don't want to disconnect something in the wrong order and damage it so can you advise me how to do it please?

I'm trying to upload photos but having problems, will try in the next post.

Thanks,
Moose

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[Randommoose]

Left battery

Middle battery

Right battery
Front of right battery

 

[Randommoose]

The Numax have 'Maintenance-Free Sealed Battery' and as we thought all three were the same we hadn't checked the third (the Lion one on the right). From the photo I can see it has screw on caps on the top - does this mean it is one that needs topping up?

I don't know whether to try disconnecting that one first and see if the others work better without it.

I don't have a clue!

 

[TheCaller]

I don't want to disconnect something in the wrong order and damage it so can you advise me how to do it please?

Here is the super-cautious approach. Some will say over-cautious & they are probably right.

Wait an hour to see if anyone points out anything I've missed.

Unplug the EHU (if connected).
Turn all 12v items off.
Turn off the master switch on the Control Panel (if fitted).
Turn off the EBL (if it has an on/off switch on the actual unit).
Cover the solar panels - chuck a blanket over them, or similar. Make sure it can't blow off.
Disconnect the +ve wire from the panels at the controller (or pull a fuse, if fitted & accessible). Tape up the end of the cable to stop it touching anything.
Now you can disconnect the batteries. Disconnect the -ve terminal first.

Reconnect in reverse order.

Some controllers rely on sensing the battery voltage to know whether they are on a 12 or 24v system. That's why it's important to reconnect the batteries before you connect the panels, so the controller picks up the correct battery voltage before getting confused by the panel voltage.

 

[Randommoose]

Thanks @TheCaller that is very helpful. A couple more questions:

If we can't reach to cover the solar panels will just removing the fuse between them and the solar controller do or not?

You say disconnect the -ve terminal first - does it matter which battery/cable is first? As there are 3 negative terminals, some of them double terminals so there are lots of cables to them.

 

[TheCaller]

The Numax have 'Maintenance-Free Sealed Battery' and as we thought all three were the same we hadn't checked the third (the Lion one on the right). From the photo I can see it has screw on caps on the top - does this mean it is one that needs topping up?

Probably. See what the label says when you get it out. If it's low on water, you could try topping it up & giving it a good charge to see if it recovers.

I don't know whether to try disconnecting that one first and see if the others work better without it.

Worth a try, if you have the time. Reading your earlier posts, I suspect you will find that all three are now well past their best, but you might just be lucky.

I don't have a clue!

We all have to start somewhere!

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[Randommoose]

Just been researching and see that batteries in parallel like this should be connected diagonally (eg positive feed to left battery (and connected to middle and right battery), negative feed to right battery (and connected to middle and left battery).
But that hasn't been done here. The right battery is only connected to the middle battery, nothing else.

 

[TheCaller]

If we can't reach to cover the solar panels will just removing the fuse between them and the solar controller do or not?

If it's a grey winter's day & the panel is covered with snow, definitely ok! If the panels are in full sun & the batteries are flat, there would be quite a lot of current passing through that wire & the sparks would fly a bit as you disconnected/pulled the fuse & then again when you reconnected it. If the controller has gone into Float mode, you will probably be ok.

You say disconnect the -ve terminal first - does it matter which battery/cable is first? As there are 3 negative terminals, some of them double terminals so there are lots of cables to them.

No, just disconnect all the -ve terminals first, then the +ve ones.

 

[Kevan]

sunWorks' DB2C solar controller is a 15amp controller so as long as your panels don't kick out any more your fine i have used Sunworks for years, like the way no wires are showing nice and tidy, I have the 30 amp system with 4 X 100watt panels on the roof, and three 135 amp batteries

 

[andy63]

was just about to start a reply, but see Simon has covered the points..

I was also going to suggest a few photos of all your connections in case its a while before things get put back in place..

its always nice to have the batteries connected up so loads and charging are shared equally, and most probably more important if they are heavily loaded, but it will still work without it...
heres the link to the explinations ... then you makes your mind up how important it is to you..
http://www.smartgauge.co.uk/batt_con.html
Andy

 

[Kevan]

Description
Dual Battery Solar Charge Controller with LCD Display.
SunWorks dual battery solar charge controller for solar panels up to 15 amps.

• Optimal charging of both engine and leisure batteries, from one solar panel.
• DuoPWM system specially designed for motorhomes and boats
• Includes our new ‘Winter’ mode. This automatically prevents either battery from discharge in low-light conditions:
  • Great for motorhomes and boats stored for long periods. Especially those with active alarm systems
• Fully automatic. No setting up routine
• Intelligent 3-stage DuoPWM charging:
  • ‘Boost’ mode to take full advantage of the available sunlight
  • ‘Absorption’ mode to maximize charge levels, and prolong battery life
  • ‘Float’ mode to maintain the batteries once they are fully charged
• Large clear LCD display provides continuous reading of the solar current and both battery voltages
  • ‘See’ your solar panel working
• Available in Black or Light Grey to enhance the interior of any motorhome or boat.
• Cables can be concealed. All cables can enter from the back, or from the side, of the controller
• Attractive, compact design
• No visible fixing screws
• Can accept solar panels of up to 240 watts, 15 amps
• Suitable for all 12 Volt leisure and engine batteries. Liquid or gel types
• Proven high reliability
• All British design

SunWorks solar panels that suit the DB2C dual battery solar charge controller:
The DB2C dual battery charge controller is suitable for use with any SunWorks solar panel over 100 watts.

We can supply rigid aluminium-framed panels, semi-flexible panels and marine grade solar panels. For example:

• Our most popular solar panel, 100 watts. The DB2C can accept up to two of these.

Installation information for use with a dual battery solar charge controller:
Installing a dual battery solar charge controller is straightforward for the competent DIY person.

Each controller comes with complete illustrated instructions. Here are the basics:

• The controller is mounted inside the boat or motorhome where it can be seen by the user.
• Mount the unit such that the cables can pass through the back or the side of the controller. A bulkhead or cupboard side are suitable places.
• A 2-wire cable must pass through the roof or deck to connect the controller to the solar panel.
• A 2-wire cable must connect the controller to each of the two batteries via a suitable fuse.

Typical connections for a motorhome:

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[TheCaller]

Just been researching and see that batteries in parallel like this should be connected diagonally (eg positive feed to left battery (and connected to middle and right battery), negative feed to right battery (and connected to middle and left battery).
But that hasn't been done here. The right battery is only connected to the middle battery, nothing else.

That's the proper way to do it. With two batteries, it hardly matters. With three, it starts to matter a bit more. With a battery bank of four or more batteries, it would be considered poor practice to do it any other way. If I were running cables from scratch, I would do it the correct way even with two batteries. If you are working with existing wiring that can't easily be re-routed to be correct, I certainly wouldn't worry for a twin battery setup & even for three, I think I would probably live with it unless I was drawing some heavy currents.

 

[nicholsong]

Martin did mention above that it could be one battery (or it could be one cell in a battery) pulling the others down.

Firstly, from the info you have given it would seem that the Numax are seale batteries, but that the Lion is not. So I would check that the electrolyte in that is enough to cover the plates. If not there may be your problem. If it has been below the top of the plates for a long time there may be damage to the plates.

So, then when following what I suggest below, start with that battery, leaving the other two in the system charging off the solar and/or EHU - they may work OK if the Lion was the problem.

The best test for whether one battery is the problem would be to disconnect the batteries from each other.

Then charge up one in situ from the solar or engine. Or since you are home, then in the house with a charger.

When charged up disconnect the charger system, leave to rest without load for 2 hours, check voltage at the terminals. Leave for further 24 hours, re-check voltage. If one battery is faulty it will show a significant drop.

A slightly better test would be to put a small load on the battery for the 24 hours, but to know what the voltage drop should be, one would need to know the Ah of the battery, the load etc. to make the calculation as to what voltage drop one should expect and compare it with the actual readings, which if significantly lower than the calculaton will indicate a problem. You might need help with the calculation.

First check the Lion for electrolyte level and go from there.

Geoff

 

[TheCaller]

Possible replacements we have looked at:
Victron MPPT - like for like replacement. £110ish Can this only work on one battery though? Has Bluetooth app display/settings. Supposed to be good in low light.
Schaudt LRM1218 - wiring up through the electroblock. More complicated? Expensive £200+
Votronic MPPT250 - like for like replacement, dual battery. No display (we would need to buy separately as our EBL isn't compatible)

Priorities:
Charging batteries! Esp in more northerly areas (UK, Ireland, Scotland, Scandinavia)
The cheaper the better
Easy to fit (DIY)
Able to get this week as we are only in England for a week.

Just to clear up any possible confusion over one battery/dual batteries:-
Dual batteries in this context means both your starter battery & your leisure battery(ies). It doesn't matter whether you have one leisure battery or three - the controller sees them as one battery.

The Victron only has one output, but as someone else said, adding a Battery Master or similar bit of kit can achieve the same result - they all work in slightly different ways, but the effect of them all is to top up the starter battery as well, directly or indirectly from the power generated by the panels.

Your existing controller (if it's wired correctly) & the Votronic both send charge to the starter battery directly. The Schaudt does it via the EBL (might be wrong on that ) & the Victron needs any one of several bits of kit that senses the difference between the leisure & the starter battery & diverts charge accordingly.

The 'good in low light' should apply to any MPPT controller, although to extract the maximum benefit from this, you need to connect your panels in series rather than in parallel. This is a double-edged sword, because panels connected in series act like a single panel if you get shading on them - it affects the whole array rather than just the one panel being shaded. It's not just a case of not parking under the trees - you need to ensure that you don't have any shadows from a roof-mounted aerial or similar. Worth considering if you need to rely on solar alone to keep the batteries healthy over winter (no EHU at home or in storage) or if you rely heavily on solar when in Northern Europe (inc. UK). Otherwise not worth the bother, especially given the need to rewire panels that are already in place. I had mine done that way because it suits my use of the van, but for many people, the shading issue outweighs any potential benefit.

The Victron app is a good alternative to having a display mounted in the van, if you already have your phone as part of your anatomy (I do). You need a bluetooth sender unit though - they are about £30-£40 from memory. It also lets you play about with the charge profile settings - useful if you want to optimise for a particular battery type or set of circumstances, like long term storage.

 

[Randommoose]

@TheCaller Again, thank you for all the helpful information. You know a lot about this! I will show that to my husband and we will consider the series/shading stuff to do with MPPT controllers. First we are just going to change the batteries as that might fix the issues. We worked out the controller was going into float or winter mode in the early morning when the batteries were below 12V so maybe it is on purpose (protection of batteries? start charging gently?). So step one is replace batteries as they are few years old anyway and have significantly deteriorated in the last 6 weeks.

We have measured the locker and think we can fit in three varta LFD90 batteries though the middle one would have to be the other way round (front to back rather than side to side) as the Vartas are 6cm longer than the current batteries.

Next question - is it possible to buy adaptors and if so what are they called? Our Numax batteries have double terminals - one normal and one screw with lots of cables attached to both. So my husband thinks we need to get something to adapt the normal single terminal into a double or replacement cables with rings preattached. Any advice?

Thank you!

 

[Randommoose]

@Kevan We think the controller might actually be ok, it might be a battery problem. Thanks for that information

@nicholsong Thank you for that process. If we had more time (and a house!) I think we would do that. But we only have a couple of days and then are off travelling again for 8 weeks so might just have to get new batteries rather than take the risk. But if we decided to test and keep them then we will follow your suggestions, thank you

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[Randommoose]

We've booked a mobile mechanic to sort out the battery wiring It looks quite complicated and we don't have any spare cable or ends so decided to stop getting stressed and get someone else to do it.
We are on EHU on a campsite until then so are sorted for electricity. Once the batteries are changed then we will see what the solar controller does.

 

[TheBig1]

not the best quality but they work well

 

[Miss Piggy]

I have a SunWorks DB2C and it's been great for the last eight years. I have two 120 watt panels connected in parallel. My last set of batteries (the cheapest I could find) lasted seven years with this system. That's pretty good! It's this one: https://sunworks.co.uk/product/dual-battery-solar-charge-controller-db2cblk/

 

[Christosurfer]

When away in Portugal we had a similar problem. Local solar supplier looked into the issue and believed one battery was not as good as the other and the van electronics would fixate on the worst one. We purchased and fitted one big Rolls deep cycle AGM battery and this solved the problem.

 

[Miss Piggy]

My Sunworks DB2C works like this: In the morning it's on Boost mode, unless either the engine or the leisure battery has fallen too low in which case it starts on Winter mode.
In Boost mode all of the solar current flows into the leisure battery. What happens then depends on the state of the batteries and the amount of sunlight available:

1. If there is lots of sunlight and the battery gets up to 14.4 volts the controller changes to PWM mode and it will then hold the voltage at 14.4 volts by reducing the current to this battery. The excess current is fed to the engine battery. I like this because it means that all of the solar current flows into my leisure battery until it's at about 80% charged. The excess is then used to charge the engine battery. Boost mode and PWM mode are used for about 2-3 hours after which time the controller changes to Float mode which works as above but with a maximum voltage of 13.8 volts.

2. If there is not much sunlight the controller still changes to Float mode after a couple of hours but all of the solar current still flows into the leisure batteries until they reach 13.8 volts. Any excess current will then go to the engine battery.

If the controller starts in Winter mode (because one or other of the batteries is too low) then the controller just splits the charge equally between the two batteries. This is good because my alarm system is constantly drawing on my engine battery and the controller saves it from getting too low. I can always be sure that I'll be able to start my engine. Once the batteries are both back up to a reasonable charge level, the controller switches back to to Float mode and continues to work as above.

I hope this helps. It seems to me that your controller is doing its job.

Regarding batteries, do I understand that you have a mix of lead/acid and Lithium ion batteries connected together? My understanding is that these two types should be charged very differently. Perhaps this has had an effect on your battery performance?

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[Hilewaychile]

Are you convinced that your batteries are OK, do they last any longer if you give it all a good charge from EHU.

I bought 100AHr Numax x 2 on the sentimental basis that I had had a spell of delivering for them all over the W. Country - and getting staff discount. But if I had read the battery performance tables http://www.thencc.org.uk/Our_Schemes/ncc_verified_leisure_battery_scheme.aspx, I would probably have bought others.

I know, because I was there, that the depot just splatted Numax stickers on big black boxes and sent me off to schlepp them. At least I didnt have to unload the 38-tonner from Romania that used to tip up with thousands of heavy black boxes on it...

Do read those tables. When your batteries eventually need replacing - that might be now or very soon - you will know what's what in the 12V leisure batt world.

My own controller is the C-TEC. Check out the D250S controller - all over the web and http://www.ctekchargers.co.uk/ctek-d250s.php. All the reviews of this thing are in the 'rave' category. It is absurdly simple to connect up and, in my experience with 2 x 100W panels up top, does a great job. Expect to pay about GBP250.

The job it is designed to do is what you are looking for - to maximise the current flowing to the batts from your charging devices. The C-TEC will get that current into your batts at 14.4V - that's a max for 12V batts - at up to 20A.

It also knows which batteries need juice and will send it to it/them. Once the priority batt is fully charged - and the C-TEC knows that only 12.8V will do, not a 1/10th of a volt less - it diverts charge to the other. And it does this from your alternator output, solar panels, the hamster on a treadmill genny ...

 

[Randommoose]

Update to say we replaced the batteries and problem solved! So it wasn't the solar controller after all, it was dodgy batteries and alternator (see below).

We ended up getting 3 Varta LFD90 for the leisure batteries and something else (I can't remember for the engine). Got a mobile mechanic to fit them as the wiring needed to be tidied.

Secondly we had the motorhome in a garage for a belt squeal on starting which we thought was a dodgy tensioner but turned out to be a seized alternator clutch. That means the alternator was stuck on all the time while driving and would have been overcharging the batteries. As we have done about 5000 miles in the last 6 weeks, it probably helped kill the batteries. So new alternator too means everything is working great!

Thank you everyone for your advice and suggestions!

Moose

 

[funflair]

I didn’t know alternators had clutches, what age van are we talking about.

Martin

 

[SandraL]

https://www.gatestechzone.com/en/problem-diagnosis/accessory-drive-system/oap-function-tests

Not an electrical clutch like an aircon compressor, just a mechanical one.

 

[Stealaway]

Modern technology even more to go wrong

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