Problem more existential than technical. But I have almost no practical experience in PV installations so I ask.
The thing is that I'm doing a friend's PV installation in a motorhome.
The problem is the number of functions to work at once:
1. Loading from a 240W PV panel.
2. Charging from 230V network.
3. Charging from the alternator (ie from the car's main battery, but only when the alternator is running).
4. Reception of energy from the battery during the day (i.e. when it is charged from PV or 230V). Reception and by means of 12V receivers and by means of a 12VDC-230VAC converter with 300W (except when there is external 230V power supply, then the converter would be turned off and 230V receivers would be taken over by 230V network).
5. Battery protection against full discharge.
So it has to be something like this:
And yes:
1. There are a lot of PV charging controllers to buy, e.g.
https://ekotaniej.pl/steca-solsum-10-10f-kontroler-ladowania-baterii-slonecznych
https://tooles.pl/regulator-adowania-solarny-1224v-panel-lcd-40a-o_1426.html
But their description explains nothing. E.g. the way PWM works. What would that mean? I know that charging the battery is like impulse in them, so maybe this is the PWM here. But somehow the voltage from the panel (from 40V) must be reduced to the battery voltage (12V). The driver is small and light. And ridiculously cheap. So how does it do it? There is no converter (with PWM
)?
It is also not known what the load is. I guess it is turned on only when there is no charging. Will connecting the load directly to the battery cause the driver to be fooled?
And they don't write there that it is an MPPT driver or even MPP.
2. There are 230V chargers so I don't even give links. The thing is, they work on their own. They may get stupid when connecting other chargers in parallel.
3. It's such a miracle:
http://techtron.pl/p2523,modul-ladowania-dodatkowego-akumulatora-separator-sla.html
But this will break the battery because it has no control over the charging current.
4. Reception will affect charging if I used the chargers listed above. Load current must somehow be added from the charging current.
5. The discharge protection must be behind all this. Therefore, the protection from the controller from point 1 cannot be used.
And here comes the existential problem.
Would you give up these dilemmas and just connect it with the elements I presented? Has anyone tried? Doesn't that break down the drivers? E.g. when two chargers are connected in parallel to the battery (one with PV and one with 230V mains)?
Should you go into your own driver? Only it is quite expensive and long-lasting project. My driver would have current stabilization from every charging source. Plus load current measurement. On this basis, it could calculate the required charging current (so as not to exceed the maximum permissible for the battery) for each of the charging sources listed. For example, when the power consumption would be small, it would only charge from PV and not from 230V (would impose the priority of charging from PV because it gives free electricity, two parallel chargers connected in parallel will not do the same).
When it's larger, it turns on 230V charging and smoothly increases its current as the load current increases.
Charging from the alternator also some clever algorithm (rather only when there is no 230V charging, and onlywhen the battery is heavily discharged (when it is close to full charge and PV gives power it would not charge from the alternator)).
The control system would even be fairly simple to do. You don't even have to use a microcontroller here.
The problem is only converters because each would have to have enough power and so come out quite expensive.
The thing is that I'm doing a friend's PV installation in a motorhome.
The problem is the number of functions to work at once:
1. Loading from a 240W PV panel.
2. Charging from 230V network.
3. Charging from the alternator (ie from the car's main battery, but only when the alternator is running).
4. Reception of energy from the battery during the day (i.e. when it is charged from PV or 230V). Reception and by means of 12V receivers and by means of a 12VDC-230VAC converter with 300W (except when there is external 230V power supply, then the converter would be turned off and 230V receivers would be taken over by 230V network).
5. Battery protection against full discharge.
So it has to be something like this:

And yes:
1. There are a lot of PV charging controllers to buy, e.g.
https://ekotaniej.pl/steca-solsum-10-10f-kontroler-ladowania-baterii-slonecznych
https://tooles.pl/regulator-adowania-solarny-1224v-panel-lcd-40a-o_1426.html
But their description explains nothing. E.g. the way PWM works. What would that mean? I know that charging the battery is like impulse in them, so maybe this is the PWM here. But somehow the voltage from the panel (from 40V) must be reduced to the battery voltage (12V). The driver is small and light. And ridiculously cheap. So how does it do it? There is no converter (with PWM

It is also not known what the load is. I guess it is turned on only when there is no charging. Will connecting the load directly to the battery cause the driver to be fooled?
And they don't write there that it is an MPPT driver or even MPP.
2. There are 230V chargers so I don't even give links. The thing is, they work on their own. They may get stupid when connecting other chargers in parallel.
3. It's such a miracle:
http://techtron.pl/p2523,modul-ladowania-dodatkowego-akumulatora-separator-sla.html
But this will break the battery because it has no control over the charging current.
4. Reception will affect charging if I used the chargers listed above. Load current must somehow be added from the charging current.
5. The discharge protection must be behind all this. Therefore, the protection from the controller from point 1 cannot be used.
And here comes the existential problem.
Would you give up these dilemmas and just connect it with the elements I presented? Has anyone tried? Doesn't that break down the drivers? E.g. when two chargers are connected in parallel to the battery (one with PV and one with 230V mains)?
Should you go into your own driver? Only it is quite expensive and long-lasting project. My driver would have current stabilization from every charging source. Plus load current measurement. On this basis, it could calculate the required charging current (so as not to exceed the maximum permissible for the battery) for each of the charging sources listed. For example, when the power consumption would be small, it would only charge from PV and not from 230V (would impose the priority of charging from PV because it gives free electricity, two parallel chargers connected in parallel will not do the same).
When it's larger, it turns on 230V charging and smoothly increases its current as the load current increases.
Charging from the alternator also some clever algorithm (rather only when there is no 230V charging, and onlywhen the battery is heavily discharged (when it is close to full charge and PV gives power it would not charge from the alternator)).
The control system would even be fairly simple to do. You don't even have to use a microcontroller here.
The problem is only converters because each would have to have enough power and so come out quite expensive.