Solar not charging Engine Battery (1 Viewer)

[kimndon]

Hi
I have 100 w solar panel which doesn't appear to be charging the Fiat battery while in storage. The engine battery was in the red when I came to check the motorhome, leisure battery showed healthy.
Do I need more solar or is there a problem with the controller?
Thanks IA.

 

[kimndon]

Sorry - guage images are after 3 hours on EHU.

 

[funflair]

You don't have the starter battery connected to the regulator. You need a battery master or battery maintainer connected between the leisure and starter battery.

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[tonka]

You have a dual regulator. Connect the second battery output to your starter battery. Twin cable and a fuse. Sorted.

 

[RM_Marine]

You haven't got trickle charge from your controller to your vehicle battery so it won't keep your battery topped up

 

[autorouter]

As other have said, the second battery output of the solar controller is not connected to anything, and could be connected to the starter battery. I can't find the manual for this controller, but if you have it you will probably find you can set the charging ratio, to for example 90% to leisure battery, 10% to starter battery.

Just one caution, if you do wire up the starter battery, keep a close eye on the voltages for a few days to make sure it is working OK. There is one type of solar controller, rebranded by different companies, that has a common positive terminal instead of a common negative terminal normally found in vehicles. In that case the second battery output is unusable, and causes problems if connected. That brown wire left unconnected makes me a bit suspicious that it's one of those.

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[funflair]

You have a dual regulator. Connect the second battery output to your starter battery. Twin cable and a fuse. Sorted.

Yes I suppose that was an option as well I was thinking it might be a long way to the starter battery from where the solar regulator is and sometimes it's just easier to go BM or maintainer route as the two battery connections are very often close together somewhere

 

[kimndon]

Gets right on my top note when you pay an expert to do a job. Why he didn't connect the starter battery I will never know!
So I will do this myself and add on another 100 watt panel at the same time. Is it worth getting a better controller or is that one ok? Funfair - sorry that went right over my head 'BM or maintainer route'.
Thanks. Don

 

[autorouter]

Even in this day and age, motorhomes are still being produced that have a good way of charging the leisure battery, but no way to maintain the starter battery if parked up for an extended time.

One solution is to have a device which trickle-charges the starter battery from the leisure battery. That's what a battery maintainer is for. It's an alternative to a dual solar controller. It trickle-charges the starter battery when the solar is charging the leisure battery. It has the advantage that it also trickle-charges the starter battery when the mains charger is charging the leisure battery. There are various brands, but a favourite on here is the BatteryMaster (BM).

The Vanbitz Battery Master

No More Flat Engine Batteries The Battery Master keeps your engine starter battery topped up by linking it to the leisure battery. This automatic one-way action passes a small trickle charge to the engine battery whenever its voltage becomes less...

www.motorhomefun.co.uk

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[autorouter]

So I will do this myself and add on another 100 watt panel at the same time. Is it worth getting a better controller or is that one ok?

I think that controller, at 20A, is good for up to 250W of panel. If you are thinking of a new controller, there are two types, known as PWM and MPPT. In the midday Spanish sun, they are about the same, but in cloudy conditions and low light the MPPT type will give you a few percent more yield. The MPPT type costs a bit more too. PWM controllers seem to be mostly for lower power solar arrays, and MPPT can be used for both low and high power, including high voltage arrays on house roofs.

 

[funflair]

Even in this day and age, motorhomes are still being produced that have a good way of charging the leisure battery, but no way to maintain the starter battery if parked up for an extended time.

One solution is to have a device which trickle-charges the starter battery from the leisure battery. That's what a battery maintainer is for. It's an alternative to a dual solar controller. It trickle-charges the starter battery when the solar is charging the leisure battery. It has the advantage that it also trickle-charges the starter battery when the mains charger is charging the leisure battery. There are various brands, but a favourite on here is the BatteryMaster (BM).

The Vanbitz Battery Master

No More Flat Engine Batteries The Battery Master keeps your engine starter battery topped up by linking it to the leisure battery. This automatic one-way action passes a small trickle charge to the engine battery whenever its voltage becomes less...

www.motorhomefun.co.uk

You now have the excellent explanation from auotorouter but I will add that there is a subtle difference between the battery maintainer from the likes of Votronic, Buttner and CBE, and the Battery Master from Vanbitz, to use the battery maintainer type you need to be sure that your solar is taking the leisure batteries above 13.6v as this is the point that the trickle charge to the starter battery starts, the Battery Master works a little differently in that it is just looking for a differential in the two voltages of something like 0.65v so your leisure batteries might only be at 12.9v but your starter battery would be maintained to over 12.2v, OK not fully charged by any means but usually enough to start the van.

The one warning re battery maintainers listed above is that they don't like LiFePO4 batteries, the Vanbitz seems to be OK with them.

 

[kimndon]

Brilliant - thanks.
So the easiest solution would be vanbitz's BM. Reading the instructions I need to find the 'Split Charge Relay'. Where am I likely to find this?

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[funflair]

What sort of electrical control system do you have, that might be an easier place to find the connections, some photos might help, but no sorry I don’t know where your split charge relay will be.

 

[royandsharont]

Even in this day and age, motorhomes are still being produced that have a good way of charging the leisure battery, but no way to maintain the starter battery if parked up for an extended time.

One solution is to have a device which trickle-charges the starter battery from the leisure battery. That's what a battery maintainer is for. It's an alternative to a dual solar controller. It trickle-charges the starter battery when the solar is charging the leisure battery. It has the advantage that it also trickle-charges the starter battery when the mains charger is charging the leisure battery. There are various brands, but a favourite on here is the BatteryMaster (BM).

The Vanbitz Battery Master

No More Flat Engine Batteries The Battery Master keeps your engine starter battery topped up by linking it to the leisure battery. This automatic one-way action passes a small trickle charge to the engine battery whenever its voltage becomes less...

www.motorhomefun.co.uk

I have charging to both my sets of batteries via the system I have but these past couple of months the sun has not been effective enough to the starter battery meaning I have had to charge it at home every 8-12 days. The leisure batteries have always been full. I’m looking now at the % setting.

So I have been looking at getting a Battery Master and spoken by email with Ash at VanBitz and also RoadPro via live chat re similar Voltronic system. Both very helpful

The purpose of posting now was to draw attention to the fact not all things are equal. The VanBitz Battery Master charges when there is a voltage drop whilst the Voltronic one needs to have a +ve EHU or solar charge producing something into the leisure battery, if not it won’t activate so can’t share the current. So there is a risk if no solar charging re cover or cloud it won’t help you.

 

[pappajohn]

Gets right on my top note when you pay an expert to do a job

Not a very expert expert.....
He used 3 core flex which is no doubt undersized anyway.
Should be twin core cable and be at least 4mmsq.

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[Drexl]

Kimndon, the charge controller and wiring don't look to be properly secured. At risk of stating the obvious the charge controller needs to be securely mounted to a surface and the cables supported with suitable clips to stop any cable movement or strain on the cable connections.

 

[stevewagner]

Gets right on my top note when you pay an expert to do a job. Why he didn't connect the starter battery I will never know!
So I will do this myself and add on another 100 watt panel at the same time. Is it worth getting a better controller or is that one ok? Funfair - sorry that went right over my head 'BM or maintainer route'.
Thanks. Don

Sorry but I wouldn’t have paid a penny for that installation. Wrong and undersized cables with the controller not secured. If I were you I would check the panel is secure on the roof and the cables are in a weatherproof box or gland for water tightnes.

 

[GeoffnDee]

Brilliant - thanks.
So the easiest solution would be vanbitz's BM. Reading the instructions I need to find the 'Split Charge Relay'. Where am I likely to find this?

I think your Motorhome may have a Schaudt EBL (119 ? ) fitted , if so , and the leisure and starter batteries are to far apart for direct connections , the rear of the EBL is a good place to connect a Vanbitz battery master as the 3 x connections needed are all there,

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[kimndon]

Yes, you are all correct. Going over to the motorhome in storage and check everything, take photos and come back and check with you guys. Will rewire this properly.

 

[royandsharont]

I have charging to both my sets of batteries via the system I have but these past couple of months the sun has not been effective enough to the starter battery meaning I have had to charge it at home every 8-12 days. The leisure batteries have always been full. I’m looking now at the % setting.

So I have been looking at getting a Battery Master and spoken by email with Ash at VanBitz and also RoadPro via live chat re similar Voltronic system. Both very helpful

The purpose of posting now was to draw attention to the fact not all things are equal. The VanBitz Battery Master charges when there is a voltage drop whilst the Voltronic one needs to have a +ve EHU or solar charge producing something into the leisure battery, if not it won’t activate so can’t share the current. So there is a risk if no solar charging re cover or cloud it won’t help you.

Just an update, I adjusted the output settings on my Truma sun controller to give 70% of charge to the vehicle battery where before it was 30%. Very easy to change settings, even for me. The van battery is charging great these past 2 days back in storage, even with low levels of sun, currently showing 13.6v on the Phantom App so I’m very pleased. At this rate I may not need to add a battery master.

 

[royandsharont]

Further update, it’s 9 days since I changed the setting, as described above, and even on the cloudy days the starter battery has not dropped below 12.6V and each day it has been charging at over 13V. Not able to say what the leisure batteries are like until I visit but I expect them to be pretty fully charged still.

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[Stealaway]

Gets right on my top note when you pay an expert to do a job. Why he didn't connect the starter battery I will never know!
So I will do this myself and add on another 100 watt panel at the same time. Is it worth getting a better controller or is that one ok? Funfair - sorry that went right over my head 'BM or maintainer route'.
Thanks. Don

The most difficult bit of a solar installation is finding a way to the Fiat starter battery under the cab floor. That's why they don't tend to bother.
The controller will be ok if you can fit a pair of 4 mm cables to the starter battery

 

[royandsharont]

After changing the Truma solar controller settings to 70% to cab 30% to leisure 12 days ago. The cab battery was seen to be charging every day via the Tracker App and today I found them to be cab 13.95V leisure 13.73V and there was 0.29A going into them even though it was very cloudy. A big big improvement

 

[kimndon]

I have fed 4mmsq. From the solar controller to the Fiat battery, (approx 1 metre in length). Just to check that I am ok to connect the red to the positive and my yellow wire to the negative??
If this works ok I might add another 50 or 100 panel. Should I rewire from the solar panel to the solar controller with 4 mmsq. Wire?
I have checked the roof gland and panel - both good.
Thanks for all your help.
Don

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[SMB]

Very informative post for someone like me who knows very little about electrical systems. I have recently acquired a CI motorhome which is fitted with a Carbest MPPT regulator. It appeared that the solar panel was only charging the leisure battery even though it appears to be a dual-charge controller. Having downloaded the manual for the regulator and looked at the wiring on mine it shows that the starter battery isn't connected.
My question is about the grounding/negative cable for the engine battery. The manual only shows a positive port for connecting the MPPT controller to the engine battery, is this because the engine battery is already grounded? And, if so, does this mean that I only need to have the positive cable attached from the MPPT to the engine battery? Apologies again for my lack of basic knowledge

 

[autorouter]

does this mean that I only need to have the positive cable attached from the MPPT to the engine battery?

In a word, yes. As you know, the alternator charges the starter battery, and the negative return from the starter battery to the alternator negative is through the engine and bodywork. The leisure battery is charged from the alternator when the engine is running, and for that to happen the leisure battery negative return needs to be connected to the chassis as well. If the solar controller negative connects to the leisure battery negative, that is already connected to the chassis and the starter negative.

The chances are the two negatives are linked together inside the solar controller anyway. If they aren't, a short link between the two negative terminals may be required.

 

[SMB]

In a word, yes. As you know, the alternator charges the starter battery, and the negative return from the starter battery to the alternator negative is through the engine and bodywork. The leisure battery is charged from the alternator when the engine is running, and for that to happen the leisure battery negative return needs to be connected to the chassis as well. If the solar controller negative connects to the leisure battery negative, that is already connected to the chassis and the starter negative.

The chances are the two negatives are linked together inside the solar controller anyway. If they aren't, a short link between the two negative terminals may be required.

Thanks for taking the time to explain it in detail, that's very helpful

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[Jimbohorlicks]

I have fed 4mmsq. From the solar controller to the Fiat battery, (approx 1 metre in length). Just to check that I am ok to connect the red to the positive and my yellow wire to the negative??
If this works ok I might add another 50 or 100 panel. Should I rewire from the solar panel to the solar controller with 4 mmsq. Wire?
I have checked the roof gland and panel - both good.
Thanks for all your help.
Don

Just check that the solar controller can accomodate an extra 50/ 100watt going into it. You may be better with an mppt controller rather than the pmw that you have now.

 

[kimndon]

Just reading above - I am not sure. Should I connect the yellow, ( brown/negative) to the battery or to ground.
Sorry - confused. This will be a temporary fix until I get more solar and a MPPT.

 

[autorouter]

Just connect the positive from the engine battery to the terminal on the solar controller. It is not necessary to connect any negative wire. There is already a negative connection to the leisure battery, and that is connected via the chassis to the engine battery negative. It's only a small trickle charge, so there will be very little voltage drop along the negative return path.

If it was a heavy current, say 20 or 30 amps, it might be worth considering a direct wire connection, but for a trickle charge current of about 1 or 2 amps the existing return path will be fine.

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