Solar charge controller

[Jagtazman]

I posted earlier than my leisure batteries are dead, and only 3 years old.
I currently have an EP solar dual battery control and a battery master but I still managed to flatted engine battery and both LFD90 leisure batteries
Appreciate van not been used for 5 months.
Engine battery seems to have recovered atm.
My concern is the solar charge may not be operating correctly and may need replacing. I am not adverse to replacing it.
Ive read before that Votronic MPP 350 are recommend units. Also read that MPP is better than PWM which is my current unit.
I see there is also 165 and 250 model. Assume difference is
350 up to 350w
250 up to 250w
165 up to 165w
I only have 1 panel which is 150w

Would the 165 be okay or is it better to get an high capacity unit?

Are they easy to replace, IE Is it just plug and play with existing wiring or would I need an expert to re wire it?

Do you feel its worth changing and the charger is prob the issue so best to replace or could I have other issues?

Thanks in advance

 

[pappajohn]

It may be over the last couple of months there wasn't sufficient sun for long enough each day to get a proper charge.
3 weeks with little or no sun is enough to discharge an engine battery due to things like radio memory, immobiliser etc
Leisure battery will depend if the control panel is turned on and what's running from the battery... Alarm etc.

 

[Jagtazman]

It may be over the last couple of months there wasn't sufficient sun for long enough each day to get a proper charge.
3 weeks with little or no sun is enough to discharge an engine battery due to things like radio memory, immobiliser etc
Leisure battery will depend if the control panel is turned on and what's running from the battery... Alarm etc.

Just the alarm was set, first time in 3 years that ive had an issue with my batteries.

Had van 4 years, had an issue in year 1 and established dealer added 2nd battery but wired it up wrong and added a completely diff battery. Took both batteries down. So replaced with 2 new ones.

 

[TheCaller]

Engine battery seems to have recovered atm.

Have you had it on a mains charger?
What about the leisure batteries. It would be better to get them charged up too before doing much else.

My concern is the solar charge may not be operating correctly and may need replacing. I am not adverse to replacing it.

Is is worth finding out if it's working, or do you want a better controller anyway? More on how to check later, if you think it's worth it.

Ive read before that Votronic MPP 350 are recommend units.

The Votronic range are well respected. All the MPPT range are dual output, like the one you are replacing. If the one you have & the Votronic are wired correctly, there is no need for a battery master as well. You should have 6 wires connected to your existing unit. 2 from the panel, 2 to your leisure batteries & 2 to the starter battery.

Would the 165 be okay or is it better to get an high capacity unit?

If you have no plans to add an additional panel, the 165 will be fine. Unless you are planning a trip to Morocco your 150W panel will never get near its rated output in Europe, so you won't be pushing the controller's limit.

Are they easy to replace, IE Is it just plug and play with existing wiring or would I need an expert to re wire it?

IF your existing wiring is correct & adequately sized, then it should be a straight replacement. I say 'if' because a dual output controller and a battery master makes me suspicious of the existing installation.

 

[Jagtazman]

Have you had it on a mains charger?
What about the leisure batteries. It would be better to get them charged up too before doing much else.

Is is worth finding out if it's working, or do you want a better controller anyway? More on how to check later, if you think it's worth it.

The Votronic range are well respected. All the MPPT range are dual output, like the one you are replacing. If the one you have & the Votronic are wired correctly, there is no need for a battery master as well. You should have 6 wires connected to your existing unit. 2 from the panel, 2 to your leisure batteries & 2 to the starter battery.

If you have no plans to add an additional panel, the 165 will be fine. Unless you are planning a trip to Morocco your 150W panel will never get near its rated output in Europe, so you won't be pushing the controller's limit.

IF your existing wiring is correct & adequately sized, then it should be a straight replacement. I say 'if' because a dual output controller and a battery master makes me suspicious of the existing installation.

Thanks for informative respinse

Vanbitz installed thr battery master when they installed the Growler system, they did not mention anything about the solar controller but might be as never noticed it as hidden in cupboard. As per pic attached. Are you saying I installed a device I didnt need Doh!
As you can see 6 wires wired up.
Only 1 green light atm as disconnected leisure batteries.

Fancy a better controller to be honest

Was thinking Votronic but recently seen the Victron SmartSolar MPPT 75/15 with built in bluetooth.
Would mean def need battery master as not dual. Suppose could just tape off the 2 wires going to the engine battery.

Or is the Votronic better even thou no. Bluetooth

Nope not had on main EHU as kept in storage, not had chance to bring home yet.

Reckon leisure batteries dead when brought home were 3.53. Had one charge for 8 hrs just taken off as dont like to use battery charger overnight currently 11.80.
Will see what reading is in morning.
Will get up to max charge and leave 2 days
If dont hold charge will just replace, but worth charging to find out.

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[TheCaller]

Was thinking Votronic but recently seen the Victron SmartSolar MPPT 75/15 with built in bluetooth.

I think Vanbitz did you a favour, intentionally or not. I have a feeling the Vanbitz Battery Master is pretty much a part of their usual install when fitting a Growler. But a favour because you now have a choice of controller. In your situation, the Victron SmartSolar is probably the one to go for - not because it may or may not do a better job as a controller than the Votronic, but because it has the built in Bluetooth. You can link your phone to the Votronic as well, but they take a different approach. While Victron are gradually adding Bluetooth to each of their individual units, Votronic have a single additional unit that handles Bluetooth & you connect all your Votronic units to it. That's fine if you have multiple units to connect, but if you just want a solar controller & you fancy the Bluetooth monitor & control system, then Victron is the way to go.

The good news is that you can assume that the Battery Master is connected as it should be. So yes, make the starter battery wires safe, install the Victron, remembering to connect the leisure batteries first, then the solar panels last. That's so the unit registers the battery voltage & knows whether it is on a 12 or 24v system. The Battery Master will then pass a trickle charge to the starter battery whenever the leisure batteries are at a higher voltage than the starter battery.

BUT, if your batteries have been as flat as that for any length of time, then they are unlikely to fully recover to any useful long term capacity. Worth a try, but be prepared for replacement.

 

[autorouter]

The BatteryMaster has the advantage that it will keep the starter battery topped up from the leisure battery, whatever is charging the leisure battery. So it will work if charging the leisure batteries from EHU. The dual controller only charges if the sun shines. If you have a BatteryMaster already, then there's no need for a dual output controller.

An MPPT controller is better than a PWM type in less than optimal sunshine - cloudy days and low winter sun for example. In full strong summer sun they are about the same.

The power 'limit' on a solar controller is fairly flexible. If for some reason there's more than the spec limit, the controller will limit the output to its maximum output. Any excess is wasted, safely. But if you're getting a new controller, no point in under-sizing it.

 

[Pausim]

The self discharge rate of a lead acid battery is likely to be 5% or more per month. What little sun is available in winter will by mid winter hit a roof mounted panel in Yorkshire at an angle of 78°, which I think means it is at best 13% efficient. I would be surprised if the batteries were not flat after 5 months.

 

[autorouter]

The self discharge rate of a lead acid battery is likely to be 5% or more per month. What little sun is available in winter will by mid winter hit a roof mounted panel in Yorkshire at an angle of 78°, which I think means it is at best 13% efficient. I would be surprised if the batteries were not flat after 5 months.

I agree with the conclusion, but it's not the self-discharge that's the problem. 5% per month for a 100Ah battery corresponds to a steady discharge of about 7mA. From your figures, a 100W panel will yield about 2Ah per day (on average, some days less than that). That corresponds to a steady current of 83mA.

However many motorhomes have a residual power drain of more than 100mA, including all the permanent connections like alarm, tracker, frost protection valve etc.

 

[Kannon Fodda]

We shouldn't expect a single solar panel to be able to keep battery systems fully charged over the winter. My 100W solar with Victron MPPT on a PVC now goes to 120Ah lithium with a Vanbitz Battery Master to top off the engine battery. There is a Strikeback alarm system. All will have been fully charged when parked up after the last use before lockdown's had started, mid December. Monitoring it all and by mid January the lithium was down to about 50% capacity, the solar panel on many days of limited daylight and cloudy weather having generated negligible amounts. I got close to putting it on EH you to top off but as days have slightly lengthened, and it got a bit sunnier, the system has recovered.

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