Solar and Alternator charging

K

Keithwill

Joined
Dec 23, 2023
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Location
Chatham, UK
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100,386
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Rimor 95 P Plus
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I'm Newbie
Recently bought a Rimor Katamarano 95Plus 2015 Renault Master coachbuilt. The arscillici Control unit that controls all the habitation electrics 230v and 12v and I assume the charging of the leisure battery has no provision for adding solar charging. A Solar panel has been fitted to a cheap PWM controller and connected direct to the leisure battery. This does charge the battery at 14v and mostly less than 2 amps unless in direct overhead sun. Question is will the charging via alternator see the 14v output from the solar into the battery and therefore a charge is not needed. I disconnect the supply to the solar controller when driving and re-connect when sited to be sure The Leisure battery gets a decent charge. The solar controller has been fitted up close to the roofline midway on an internal partition, and cables run down in a panel then under the floor. Modifying the wiring layout would be a nightmare.
Any advice appreciated.
KW
 
Never touch my solar. Just let it do it's thing. I am guessing the solar will see raised voltage and back off ....
 
Is there any indication of the current (Amps) into and out of the leisure battery? In the manual I've seen, the manual isn't clear whether the amps value is displayed or not. It says it's a positive number for discharging, and negative for charging. If that's correct, you could see for yourself what value the amps reaches when the solar is working, and see what happens when you start the engine so that the alternator is also charging.
 
autorouter said:
Is there any indication of the current (Amps) into and out of the leisure battery? In the manual I've seen, the manual isn't clear whether the amps value is displayed or not. It says it's a positive number for discharging, and negative for charging. If that's correct, you could see for yourself what value the amps reaches when the solar is working, and see what happens when you start the engine so that the alternator is also charging.
Click to expand...
I have no way of getting an amps reading for the battery either in or out. The habitation switchgear and info panel only has a pushbutton battery voltmeter type of indicator for charge level, which when solar is connected always has 4 leds lights up (full). The solar cannot give any indication of alternator output or battery amps input that is why I disconnect the solar so as not to damage it or stop alternator from non charging. I was looking for an answer to if and how the two could be left connected without damag, and without a major re-wiring using £300 bluetooth enabled multi functional wonder box.
 
You could use a DC clamp meter, clamped round the wires to the leisure battery negative. That would tell you the amps flowing in/out without having to disconnect any wires. To measure amps with a standard multimeter you would have to disconnect the wires and pass the amps through the meter - a clamp meter avoids that problem.

But watch out, many clamp meters can not measure DC amps. Even when labelled 'AC/DC Clamp Meter' some of them measure AC and DC Voltage, but only measure AC amps, not DC amps.

But I think you'll find that there's no problem with solar, alternator and mains charging interactions.
 
Jev88 said:
I am guessing the solar will see raised voltage [from the B2B] and back off ....
Click to expand...
I think you have the logic correct. The unit with the highest voltage will do the work. But this is not necessarily the unit which could deliver the highest current.

But I am not convinced that it is always the solar which backs off.

I came to the conclusion in France last year that, in my case, it was B2B which backed off, so I put a switch in the lead from the solar panel to the regulator so I knew that the B2B would be working.

This year, we are using a different B2B and we have not seen the sun yet, so I can not say which will back off.
 
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LithiumConvert said:
I think you have the logic correct. The unit with the highest voltage will do the work. But this is not necessarily the unit which could deliver the highest current.

But I am not convinced that it is always the solar which backs off.
Click to expand...
Not so. I have 2 solar controllers for my 4 panels. One is Victron, the other Votronic. I have a Victron BMV with a shunt. Using Victron's Bluetooth app I can see what amps the Victron solar controller is putting in and also the BMV tells me what the total net amps that is being putting in, or out. The BMV figure is larger than the Victron's solar figure, the difference being the amount the Votronic solar is also putting in.
 
I don’t think the alternator can be that clever, throwing in whatever it can until resistance in the battery makes it less possible. I always felt the alternator would affect the operation of the solar more than the other way round, putting the solar in to float mode.

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Of course, in an ideal world, all of the various chargers would be delivering the same voltage.

And in individual cases the voltages, are going to be within tolerances such that many people will not see the effect.

But you should not assume that we are all going to be so lucky with our ad-hoc charging systems collected over many years.
 
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LithiumConvert said:
Of course, in an ideal world, all of the various chargers would be delivering the same voltage.
Click to expand...
In the first stage of a 3-stage charging profile (the bulk charge stage) that is exactly what happens. The battery voltage is below the Absorption Voltage setting of all the charging sources. The chargers are in Constant Current (CC) mode, not Constant Voltage (CV) mode. CC mode doesn't behave like you expect from using CV mode supplies like batteries and ordinary power supplies

The charger pushes out its maximum amps, and the voltage rises to whatever is required to enable the maximum amps output. Each charger keeps measuring the resulting voltage. As long as the battery voltage is below the Absorption Voltage setting, it will keep pushing out the maximum amps. It's the same for all the charge sources.

Ideally all the chargers will have exactly the same Absorption Voltage setting, but in reality they will probably all be much the same. So they will all be pushing out their maximum amps.

When the battery voltage reaches one of the Absorption Voltage settings, that charger will flip to Absorption mode. The others will carry on in Bulk Mode until the voltage exceeds the absorption voltage of all the chargers, at which point they will all be in Absorption Mode. The battery will be about 80% charged by this point.

I could carry on and describe what happens in the Absorption mode and Float mode, but although the reasons are different the result is much the same - all the chargers contribute to the charging.
 
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autorouter said:
When the battery voltage reaches one of the Absorption Voltage settings, that charger will flip to Absorption mode. The others will carry on in Bulk Mode until the voltage exceeds the absorption voltage of all the chargers, at which point they will all be in Absorption Mode. The battery will be about 80% charged by this point.
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Sorry but I just got confused. Will the charger “flip to float mode”?
Are bulk, absorption and boost different words for the same stage in a charging profile?

Is it fair to think that because one charger is giving an absorption charge to a battery, the other charge source won’t “see” that voltage and consider the battery to be full and not contribute?

TIA Cush
 
Oh, I do like theories.

But, the reality can be very different for lots of reasons. (often caused by dealers not using sense wires or having chargers set to wrong values or using wires that are too thin, too long, etc.).

The reality is that users see chargers apparantly not workiing and ask why?

Explaining the perfect situation theory to them does not help. If they had a system working as you describe, they would not be posting here.

What they want to know is why is it not working for them
 
Cush said:
Sorry but I just got confused. Will the charger “flip to float mode”?
Are bulk, absorption and boost different words for the same stage in a charging profile?
Click to expand...
In the UK we call the three stages of the charging profile bulk, absorption and float.

Bulk and absorption are two distinct stages in a charging profile. The bulk stage is the first 80% or so, the absorption stage is the final 20%. When it's full, it goes to the float stage to keep it full without overcharging.

In translated user manuals it is common to get the translation wrong and use words like boost, but it's usually easy to figure out which of the three stages they really mean.
Cush said:
Is it fair to think that because one charger is giving an absorption charge to a battery, the other charge source won’t “see” that voltage and consider the battery to be full and not contribute?
Click to expand...
Let's consider two cases, where you connect a second charger when the first charger is already charging a battery. If it's for example 50% charged, then the first charger will be in the middle of the bulk stage. If the absorption voltage setting is 14.4V, then the battery voltage won't have reached that voltage yet, so maybe it's at say 13.8V. The second charger will see that voltage, and decide that it is below its absorption voltage setting. So it will turn on in bulk mode, pushing out its maximum amps, until the battery reaches the absorption voltage setting. In other words, it will contribute its full output to the charging process.

In the second case, for example when the battery is 90% full, then the first charger will be in the middle of the absorption stage. It will be keeping a fixed voltage at the absorption voltage setting, and measuring the amps to see if it's fallen low enough. If you connect a second charger, it will see that the voltage has reached the absorption voltage, so it will flip immediately to the absorption stage, and apply a fixed absorption voltage, and measure its amps to see it has fallen low enough.

The interaction is a bit complicated, but the result is that the battery will get the amps it requires to bring it to full charge. It may be that one of the chargers will cut out, but the other charger will be more than capable of supplying the amps needed at that time. Because if it wasn't, then the other charger wouldn't have cut out in the first place. In other words, the battery will get whatever it needs, from either one charger or both of them.

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LithiumConvert said:
Explaining the perfect situation theory to them does not help. If they had a system working as you describe, they would not be posting here.

What they want to know is why is it not working for them
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Smart chargers are not easy to understand for anyone without a technical background, and the manuals are often bad translations from another language. The first stage in fixing a problem is understanding what ought to be happening if everything is working.
 
Keithwill said:
Recently bought a Rimor Katamarano 95Plus 2015 Renault Master coachbuilt. The arscillici Control unit that controls all the habitation electrics 230v and 12v and I assume the charging of the leisure battery has no provision for adding solar charging. A Solar panel has been fitted to a cheap PWM controller and connected direct to the leisure battery. This does charge the battery at 14v and mostly less than 2 amps unless in direct overhead sun. Question is will the charging via alternator see the 14v output from the solar into the battery and therefore a charge is not needed. I disconnect the supply to the solar controller when driving and re-connect when sited to be sure The Leisure battery gets a decent charge. The solar controller has been fitted up close to the roofline midway on an internal partition, and cables run down in a panel then under the floor. Modifying the wiring layout would be a nightmare.
Any advice appreciated.
KW
Click to expand...
You don't need to do anything, the battery will take some from the solar if is available and the difference from the alternator. If all charging sources are set at a equal absorb, 14v it doesn't matter how many charging sources are in the system. They will share the work of charging. As the battery it fills up, the internal resistance rises as well, so it will only take in what 14v allows, regardless from where it comes. Simple physics.
 
Just to be sure can I assume that all the technical terms regarding bulk absorbtion and float all apply to a basic solar controller Direct to the Lead acid leisure battery and the split charge that is managed by the Leisure electrical {ArSilicii] control. To me it sounds like the battery is the smartest bit of kit in my setup, telling all these components what to do:notworthy:
 
I am inclined to agree with the view that all some people need to know is that a permanently high voltage from one charger will effectively turn all the others off.
 
My 2015 Renault based Rimor has not got a "smart" alternator. All the 230v and 12v components are controlled by an ArSilicii made control box. The Lights and pumpswitches are on an "analog" switching unit with a Test button that displays battery level[voltage] water level and a e/hookup warning lamp. A lot of comments on this charging problem make sense if all components are "smart interconnected" using electronic switchgear and lithium batteries. The Funsters with older low tech systems need a way to integrate new solar setups without the expense of running 15mm cables the length of the van with new B2B charge controllers when a simple switch off of a small solar input whilst on the move will not compromise the higher amperage charge of an alternator.

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Keithwill said:
My 2015 Renault based Rimor has not got a "smart" alternator. All the 230v and 12v components are controlled by an ArSilicii made control box. The Lights and pumpswitches are on an "analog" switching unit with a Test button that displays battery level[voltage] water level and a e/hookup warning lamp. A lot of comments on this charging problem make sense if all components are "smart interconnected" using electronic switchgear and lithium batteries. The Funsters with older low tech systems need a way to integrate new solar setups without the expense of running 15mm cables the length of the van with new B2B charge controllers when a simple switch off of a small solar input whilst on the move will not compromise the higher amperage charge of an alternator.
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That's what Autorouter was telling you.

You don't need to switch anything off.

And you are also correct, in that the battery is the smartest part of your system, it knows what it wants and takes the current from anywhere it can get it, split charge, solar, any and all chargers.

No need to turn any charger off, just let them do their thing.
 
Keithwill said:
I disconnect the supply to the solar controller when driving and re-connect when sited to be sure The Leisure battery gets a decent charge
Click to expand...
Like you, I am still firmly of the opinion that I get a better/faster charge whilst driving if I switch off the solar panel.

Maybe not the case for everyone, but if it works for us then why not?
and so simple to do.
 

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