well i measured up today for my Solar installation

[Bart]

@Misterg thanks for the link , typical by the time i add P&P its like £20 dearer that the 15amp version from ebay/photonic universe lol

 

[Bart]

is 6mm2 cable thick enough for the above solar setup ?

 

[tonyidle]

That's what I thought, so how would 2 solar controllers get along on the same battery? One will offer slightly higher voltage than the other.. I would have thought

Correct but irrelevant. If the battery state is low enough both will contribute. As the battery charges and its voltage rises one will give up before the other. You are over-thinking the non-issue.

 

[Minxy]

Correct but irrelevant. If the battery state is low enough both will contribute. As the battery charges and its voltage rises one will give up before the other. You are over-thinking the non-issue.

Interesting ... so does that mean that if you have a 10a and 15a charger you'll actually get less benefit than a single 25a charger?

 

[tonyidle]

Interesting ... so does that mean that if you have a 10a and 15a charger you'll actually get less benefit than a single 25a charger?

Not really. A charger will only charge at a current determined by the state of the battery and the open circuit (disconnected) voltage of the charger. There are other considerations but simplistically that's how it is. So for example your vehicle may have an alternator capable of safely supplying 70 Amps. But it's output voltage is restricted to around 14.2Volts so as the battery voltage rises towards 14.2 it opposes the alternator, reducing the current flow, until it actually reaches 14.2 at which time 0 Amps will flow. Chargers are the same. When the battery terminal voltage is below the voltage output by all the chargers they will all contribute towards the current that is charging the battery. As battery terminal voltage rises the charger with the lowest voltage output will drop off first. The last to go, as the battery voltage rises and charging current drops towards zero, will be the one with the highest voltage output. Regardless of the capability of any individual charger it is the battery and its state of charge that determines the charging current.

Going back to the alternator it's current capability is determined more by how much current is needed to run the vehicle services (engine management, lights, environmental services, etc) than by what's needed to charge the battery.

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[Minxy]

Not really. A charger will only charge at a current determined by the state of the battery and the open circuit (disconnected) voltage of the charger. There are other considerations but simplistically that's how it is. So for example your vehicle may have an alternator capable of safely supplying 70 Amps. But it's output voltage is restricted to around 14.2Volts so as the battery voltage rises towards 14.2 it opposes the alternator, reducing the current flow, until it actually reaches 14.2 at which time 0 Amps will flow. Chargers are the same. When the battery terminal voltage is below the voltage output by all the chargers they will all contribute towards the current that is charging the battery. As battery terminal voltage rises the charger with the lowest voltage output will drop off first. The last to go, as the battery voltage rises and charging current drops towards zero, will be the one with the highest voltage output.

Going back to the alternator it's current capability is determined more by how much current is needed to run the vehicle services (engine management, lights, environmental services, etc) than by what's needed to charge the battery.

I think I need to clarify my question which was in relation to the solar panel controllers, not the alternator (ie when stationary for a few days) - if there was a single 25a charge controller with all solar panels linked to it (ie 2 x 50w and 2 x 150w), the input from all the solar panels would be utilised until the batteries were full, however if there was a 15a one with 2 x 50w panels linked to it, and a 20a one with 2 x 150w panels linked to it, from what you've said would the 15a one stop putting oomph in before the 20a one? If so would that mean you lose the input from the 2 x 50w panels thus prolonging the amount of time for recharging? Or have I misunderstood? I've only had to take a greater interest in the solar electrickery input side of things since we got a camper with an all electric fridge freezer so am still learning.

 

[Richard n Ann]

would the 15a one stop putting oomph in before the 20a one? If so would that mean you lose the input from the 2 x 50w panels thus prolonging the amount of time for recharging?

Possibly yes, being microprocessor controlled only the designers of the units will know how they would react for sure. The paragraph I quoted above (post 19) explains how parallel controllers need to be linked to be able to talk to each other and coordinate the charge.

 

[Misterg]

...If so would that mean you lose the input from the 2 x 50w panels...

No. (With the proviso that both controllers are set to similar charging profiles.)

Each controller will keep doling out ‘oomph’ until the battery voltage rises to the programmed end point and the charging current drops below the programmed end point. This will only happen when the battery is fully charged.

 

[Richard n Ann]

No. (With the proviso that both controllers are set to similar charging profiles.)

Each controller will keep doling out ‘oomph’ until the battery voltage rises to the programmed end point and the charging current drops below the programmed end point. This will only happen when the battery is fully charged.

Until one of the panels hits a bit of shade, the output drops a bit, then the other one takes over and the shaded one backs right off.

That's what mine does anyway when the mains charger is switched on or alternator starts charging. I think the company linked to above are correct (certainly in my case) the controllers need some sort of coordination.

 

[tonyidle]

Possibly yes, being microprocessor controlled only the designers of the units will know how they would react for sure. The paragraph I quoted above (post 19) explains how parallel controllers need to be linked to be able to talk to each other and coordinate the charge.

That is true only if it were possible to connect all charging sources with a data link so they could act in unison. It would mean that their 'smart' profiles (the profile that determines boost, bulk, float outputs) could act as one. The systems used on a motorhome are a mix of smart and simple. Certainly the van charger and the solar controllers are smart but each manufacturer has his own method of setting the charge profile, but the alternator doesn't adhere to any of them and is as far as our use is concerned, a very simple 14.something source. Again, as far as our use is concerned, as each source of charge comes on line it will try to determine what state the battery is in and at what point on its profile it should start. However it will be unable to do so because, even if it could match other charge sources, there will always be a load on the battery from from one or more hab services.

So, as I said earlier, it is possible to over-think how a number of charge sources will interact and equally impossible to come to any conclusion. Nothing we use is that clever and each manufacturer assumes his device is acting alone. What we can do is connect as many charge sources as we wish to the hab battery. Each will contribute if the battery requires a substantial charge and as that requirement reduces as the battery nears full charge the charger whose maker set the highest bulk, then eventually float, voltage will be the last man standing. It will all work well, each charge source will do its job, and the battery will be taken care of.

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[tonyidle]

I think I need to clarify my question which was in relation to the solar panel controllers, not the alternator (ie when stationary for a few days) - if there was a single 25a charge controller with all solar panels linked to it (ie 2 x 50w and 2 x 150w), the input from all the solar panels would be utilised until the batteries were full, however if there was a 15a one with 2 x 50w panels linked to it, and a 20a one with 2 x 150w panels linked to it, from what you've said would the 15a one stop putting oomph in before the 20a one? If so would that mean you lose the input from the 2 x 50w panels thus prolonging the amount of time for recharging? Or have I misunderstood? I've only had to take a greater interest in the solar electrickery input side of things since we got a camper with an all electric fridge freezer so am still learning.

That's partially true. By the time one of the controllers stopped charging the battery would not accept its output anyway as the charge current needed would be tapering off as the battery terminal voltage would have risen. There's no reason to assume the panel with the lower Wattage output would drop off first. That would depend on the parameters designed into the controller. (and see @Richard and Ann s post). On the face of it interconnecting the panels and using a single controller would give the best result. But it's never that simple: there are losses involved in mixing and matching panels anyway unless they're identical in every way so having separate controllers might (or might not) be the better option.

 

[Misterg]

It will all work well, each charge source will do its job, and the battery will be taken care of

Very much that^

Don’t over-think it!

 

[TheCaller]

P.S forgot to say i will be reinstalling my battery master ( the one that trickle charges the cab battery once the leisure batteries reach a certain charge )

Why not get a Votronic one instead with dual ability to charge your leisure and hab batteries ... they do a 430 one which would capable of handing 400w.

I've told them Minxy they won't listen

Because the OP already has a battery master to do that job.

 

[Minxy]

Because the OP already has a battery master to do that job.

... but it would easier surely to just put in a duo ...

 

[TheCaller]

... but it would easier surely to just put in a duo ...

Not if he prefers the Victron app, which is very good. I'm not sure if there is a Votronic or other equivalent.

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[Richard n Ann]

Not if he prefers the Victron app, which is very good. I'm not sure if there is a Votronic or other equivalent.

An app would be good then I can monitor it whilst driving or waking up in the night I could quickly check the discharge in bed without disturbing Ann... actually it probably wouldn't be very good for my mental health

 

[Minxy]

Not if he prefers the Victron app, which is very good. I'm not sure if there is a Votronic or other equivalent.

There appears to be some sort of app ...

https://www.votronic.de/index.php/en/products/measuring-display-systems/energy-monitor-app

 

[Silver-Fox]

or waking up in the night I could quickly check the discharge in bed without disturbing Ann

That doesn’t sound good

 

[Richard n Ann]

There appears to be some sort of app ...

https://www.votronic.de/index.php/en/products/measuring-display-systems/energy-monitor-app

WOW graphs! Data! Tables! Comparators! Information heaven!
.
. .
.

. No, Ann says we don't need it. I'm not looking. La, la, la, la

 

[TheCaller]

There appears to be some sort of app ...

True, but you have to buy the separate Bluetooth module to connect to the controller. That used to be the case with Victron, but current controllers have Bluetooth built in.

If the OP was also fitting the Votronic battery monitor, then it would be well worthwhile, because the Bluetooth module & app works with both.

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[Bart]

True, but you have to buy the separate Bluetooth module to connect to the controller. That used to be the case with Victron, but current controllers have Bluetooth built in.

If the OP was also fitting the Votronic battery monitor, then it would be well worthwhile, because the Bluetooth module & app works with both.

I've installing the victron 100/30 Bluetooth solar controller, along with the victron 712 Bluetooth battery controller C/W shunt.
I had the victron 700 battery monitor in our last MH , it is a good bit of gear yy yy

 

[Bart]

So I've got my solar wired up today, and just waiting for delivery of the batteries ( Varta LFD 90s), and I have a question relating to the rotary switch setting for the batteries, what setting matches the above batteries

 

[Richard n Ann]

Wet flooded lead acid

 

[Bart]

Wet flooded lead acid

Sorry I should of added the Screenshot of the manual, as I looked for flooded lead, but did not see it.

 

[Richard n Ann]

Position 2 going by voltages. But it's not very clear is it. Anyone confirm this?

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[Bart]

So I finally got the Varta LFD 90 batteries &, Victron controller & solar all hooked up and I've left the controller at the default rotary setting of 2 and here are some screenshots, can anyone confirm these are the correct charging voltages for the batteries.

 

[Richard n Ann]

Looks OK to me. It didn't charge fully on the bulk charge before it timed out, so it's still taking 1.7amps. Ours does that.

 

[Richard n Ann]

I think I'm going to fit a big pull out fuse on the solar panel incoming wire so I can start the charge when I get up and the sun is stronger.

 

[Lenny HB]

Should be OK as the Victron as standard has a 4 hour absorption phase on Gel settings.
I think with the Victron if you buy the USB dongle you can program it yourself and set your own parameters.

 

[Bart]

Looks OK to me. It didn't charge fully on the bulk charge before it timed out, so it's still taking 1.7amps. Ours does that.

Thanks

Should be OK as the Victron as standard has a 4 hour absorption phase on Gel settings.
I think with the Victron if you buy the USB dongle you can program it yourself and set your own parameters.

Yip that SS is from the Victron Bluetooth app, and yes you can set custom parameters, but I'm not sure what I should set them to.
Here is what I can change.

Also I'm unsure what "manual equalisation" does.

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