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Charging batteries from PV and other sources with simultaneous energy reception.

atom1477 8790 18
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  • #1
    atom1477
    Level 43  
    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:
    Charging batteries from PV and other sources with simultaneous energy reception.



    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 :D )?
    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.
  • Helpful post
    #2
    Jan_Werbinski
    Level 33  
    1. Any controller.
    2. It does the motorhome's electric block.
    3. It fixes the alternator.
    4. These functions are handled by the electric block and converter. To have automatic switching of 230V receivers between the inverter and power supply from the outside, use an inverter like mine.

    Does this motorhome have an electric block? You plan it anyway or you don't know it. Elektroblock is such a switchboard. Usually from Schaudt.
    First, write us what the electroblock has. And start the whole project from the beginning, after considering its existence / non-existence. In my opinion, you are overwhelmed because you do not mention the electric block and the existing installation. Like you would never have done camper electronics in your life.

    My Hymerek has flexible panels and a Votronic MPP 350W controller that charges both engine and bodywork batteries. Votronic sine converter that automatically shuts off after connecting a 230V extension cable. The electroblock does the rest.
  • #3
    atom1477
    Level 43  
    The motorhome contains absolutely nothing. Everything is stolen. There were only cables left in places where they could not be stolen because they went in hard to reach places.
    I would add that originally there were no solar panels, so returning to the original installation is not an option anyway. At most, you could choose a driver from another motorhome.
    And I don't really have experience with it. This is the first time I've done anything in a motorhome. And probably the last one.

    Quote:
    4. These functions are handled by the electric block and converter. To have automatic switching of 230V receivers between the inverter and power supply from the outside, use an inverter like mine.

    So what? I ask out of curiosity because I already have an inverter and switching.
  • Helpful post
    #4
    Jan_Werbinski
    Level 33  
    inverter
    http://votronic.de/index.php/en/products2/sine-inverters/standard-version/smi-300-nvs
    Regulator
    http://votronic.de/index.php/en/products2/sol...trollers/standard-version-mpp/mpp-350-duo-dig
    Or Chinese Tracer also very good and much cheaper.


    As water indicators you can e.g. this
    http://votronic.de/index.php/en/products/level-measuring/combi-panels

    But Votronic is an expensive company. I suggest some cheap Chinese inverter. Tracer regulator. Make a switchgear with fuses for everything. In general it will be hard for you. If you were a camper user and gouge, you would know what's going on. If you don't know, your chances are zero unless you waste a lot of time studying. You do not mention the issue of powering the refrigerator, hot water, water tank level indicators and sewage. It will be really hard without an electroblock.

    Therefore, maybe start with buying a new electroblock?
    E.g. here for 1800.
    http://allegro.pl/elektroblok-ebl-208-panel-wskaznik-kena-wroclaw-i6841403421.html

    Once you mount it and everything works, then you will add solars with a regulator and inverter. For now, get rid of the solar panels and inverter. It will only be at the end.
  • #5
    atom1477
    Level 43  
    I think it's the opposite for me. The entire power supply to the receivers is very simple, but charging the batteries is a problem. You write as if it were the other way around. You probably look at it as a user or installation composer (from ready modules).
    And I do the opposite. Making my own charging controller from PV or alternator is not a problem for me. It is only about the sensibility of doing and the cost.

    I intentionally did not mention powering the receivers, because I have already done it, and it does not matter. The fridge, water pump, water level indicator, toilet flush and lighting are on 12V (and only on 12V, e.g. the fridge does not have a separate 230V input). There is no heating of water and there is not.
    There are almost no receivers on 230V. It is supposed to be only a TV set and something that may eventually appear unexpectedly in the future (phone charger, shaver, etc.).

    I am not convinced by these charging drivers.
    I don't understand how it would work.
    Charging from the alternator. Ok but on my own.
    Loading from the solar. Ok but on my own.
    Charging from 230V network (i.e. from this electroblock). Ok but on my own.
    Each of these modules gives some charging current. Which must be large but not greater than the permissible battery charging current.
    And here these 3 blocks are to be connected to the battery in parallel.
    And that's what I'm interested in. What in this whole system would prevent exceeding the maximum charging current?

    And as for the electroblock, it's probably too late to buy. I still read, but so far it looks like he would do what I have already done myself.

    Unfortunately, I have no experience and I don't know how it is usually done. As well as I do not know the vocabulary (I hear about electroblock first, although its principle of operation is simple and obvious to me). But it's not so bad. The case certainly does not overwhelm me because I know from the kitchen how it all works.
  • #6
    Jan_Werbinski
    Level 33  
    atom1477 wrote:
    What in this whole system would prevent exceeding the maximum charging current?

    Maximum voltage of each charger.
    For example, the regulator is set to 14.4V and that's it. Elektroblock also has some setting. Probably 14.4V to AGM. If several chargers tried to charge it at once, the voltage will increase and stop. While driving, solar charging usually turns off, but not always. I connect to the power grid only in winter, and then the sun does not matter.
  • #7
    atom1477
    Level 43  
    It won't work for me.
    Once that the permissible charging current is exceeded.
    Two that it will not be possible to provide the correct charging mode (IUoU) because the chargers will go to the oU mode too soon.
    Three that chargers will go crazy. The end voltage of all chargers is not exactly 14.4V. One of them will decide that the 14.4V voltage has been exceeded. And it will be the first to enter the oU mode. Which? Lottery. What the others will do then is unknown.
    And what if the charger pulses with pulsation? So this mode called PWM. On an uncharged battery, the current pulse from one of the chargers will exceed 14.4V and the other chargers will turn off even though the battery is not charged yet.

    And there is still the matter of simultaneous current consumption from the battery.

    I read descriptions of ready drivers. Is it solar chargers. Are these motorhome chargers. And despite the huge price (over 1000 PLN) they had basic disadvantages that I am just talking about.
    That's why I'm thinking about my own charging drivers.
    I just want a system that works constantly, not like yours, that the 230V power supply is almost unused and the solar power is turned off while driving. No wonder then that there is no problem because 3 chargers never work at once.
  • #8
    Jan_Werbinski
    Level 33  
    It will not exceed the maximum current. Maybe because my battery is almost never fully discharged? If it is heavily discharged and goes e.g. 20A / 240W from solar panels, then after starting the engine and normal driving charging from solar panels decreases e.g. to 100W. It happens automagically and I have never thought about it.
    Charging mode does not matter. I don't have to have a fully charged AGM constantly. It is enough if it is not heavily discharged and is charged to the end almost every day by driving the alternator or by stopping the solar.
    It just works. And now :)
    The Votronic regulator is 120-200EUR and I have not seen more expensive and better ones and I have been to Tracera and I have tested it many times. Votronic has support for several types of lead and LiFePO4 batteries. I don't think you would do better.
    Why do you need a system that works constantly? Where should this energy go? I will go 120W to the fridge when I force it manually or the solar controller will switch on itself via AES.
    Why should I connect 230V if the sun is shining or I'm going? It doesn't make sense. 230V is connected at a standstill especially in autumn and winter, but then we do not start the engine because what for? The manual probably even prohibits starting the engine while connected to 230V.
    So in practice I have a situation that the alternator charges mainly the engine battery and the bodywork, and at the same time the solar tries to help him but turns off quite quickly allowing the alternator to charge. At standstill 230V keeps charged batteries and solar is also bored.
    I don't understand what your problem is.
    You write about some flaws, but these are your dry theories because you have never ridden a camper. :-) These problems do not exist. It just works.

    Let's imagine that we want to exceed the maximum charging current. It will be very difficult. If the battery has discharged after a night and we start in the morning, it will be charged from the alternator because the solar panels do not give power yet. If in the afternoon, the solar panels have already charged him a bit and the alternator will do the rest. Connecting 230V in the morning it will be charged from 230V, and in the afternoon it has already been charged with solar panels. I do not know how to exceed the maximum current. It is almost impossible. If this happens, it will be a temporary situation and it is unlikely to happen again.
  • #9
    atom1477
    Level 43  
    The problem is that charging mainly goes from the solar and not from the alternator.
    And you come out that it is so.
    The solution would be only what you describe, i.e. giving up loading from many sources at once. Fortunately, it's not for me so I'll see what the owner of the motorhome will say. I will only add that he has been driving (and a lot) camper for years. It was from him that such ideas came.

    PS. You can link to "Votronic 120-200EUR" because I can't find anything like that? (I also tried to search without 200EUR assuming that this is the price :D )
  • #10
    Jan_Werbinski
    Level 33  
    atom1477 wrote:
    The problem is that charging mainly goes from the solar and not from the alternator.
    And you come out that it is so.
    The solution would be only what you describe, i.e. giving up loading from many sources at once. Fortunately, it's not for me so I'll see what the owner of the motorhome will say.

    Charging which battery?
    I would like that too, but it doesn't work. You would have to limit the tension and then you will be undercharged during cloudy days.
    It only annoys me when having a fridge switched to 12V and full sun I see that the energy goes from the alternator instead of solar. This type has it and in the name of simplification of design and priority of long life and high battery level, we devote energy from solar panels to fuel. Lost money is penny. There is no point in worrying about it.

    The solution may be to separate the bodywork circuit from the alternator while driving. This will be done by a solar controlled relay and an alternator signal. But I don't want to play it. I usually don't drive more than 300km / day.

    Added after 3 [minutes]:

    atom1477 wrote:

    PS. You can link to "Votronic 120-200EUR" because I can't find anything like that? (I also tried to search without 200EUR assuming that this is the price :D )

    From 99 to 200 EUR
    http://www.ebay.de/itm/Votronic-MPP-Serie-165...lage-/142104415132?var=&hash=item2116154b9c:m : mNgl5dd0Redb7oMYQlInr4g
  • #11
    atom1477
    Level 43  
    Jan_Werbinski wrote:
    Charging which battery?

    This additional one. No engine starter.

    Jan_Werbinski wrote:
    I would like that too, but it doesn't work. You would have to limit the tension and then you will be undercharged during cloudy days.

    Why not? Not only go with the solar but:
    Quote:
    The problem is that charging goes mainly from the solar and not from the alternator.

    So charging from the alternator also has to be. But the controller is to ensure that it goes a lot from the solar and only the remaining part of the alternator. Technical is absolutely possible. And it doesn't change anything about the battery charge. Energy redirection would be done not by reducing the voltage but by controlling the current capacity of the solar and alternator chargers.

    Jan_Werbinski wrote:
    It only annoys me when having a fridge switched to 12V and full sun I see that the energy goes from the alternator instead of solar. This type has it and in the name of simplification of design and priority of long life and high battery level, we devote energy from solar panels to fuel. Lost money is penny. There is no point in worrying about it.

    The matter of long life is questionable because even the best controller if it does not distinguish between the current and the current received by the load, it will not provide a good way of charging.
    That is why I think that my own driver may be better than ready, even this Votronic.

    Jan_Werbinski wrote:
    The solution may be to separate the bodywork circuit from the alternator while driving. This will be done by a solar controlled relay and an alternator signal. But I don't want to play it. I usually don't drive more than 300km / day.

    I'll think about that.

    Jan_Werbinski wrote:

    So 120 was also not part of the designation?

    Have you done more motorhomes or just your own?
  • #12
    Jan_Werbinski
    Level 33  
    atom1477 wrote:

    So charging from the alternator also has to be. But the controller is to ensure that it goes a lot from the solar and only the remaining part of the alternator. Technical is absolutely possible. And it doesn't change anything about the battery charge. Energy redirection would be done not by reducing the voltage but by controlling the current capacity of the solar and alternator chargers.

    If you want to do it for an idea, try it. The economic sense is none. The switching relay has some chance to turn in saved fuel, but the controller rather never. It is better to spend this money on an additional battery or increasing the number of solar panels.
    In practice, batteries are simply always charged with some oversizing. To increase the energy recovery from solar panels I need to switch the fridge to 12V. There is more room here.
  • #13
    atom1477
    Level 43  
    The biggest number of switches bothers me the most. But let's see what the camper guest will say.
  • #14
    Jan_Werbinski
    Level 33  
    atom1477 wrote:

    So 120 was also not part of the designation?
    Have you done more motorhomes or just your own?

    120 is the price. It turned out that the smallest ones cost from 100EUR. In my opinion, it's better to pay twice as much for Votronic than Tracer. Whoever puts these two regulators next to each other will understand how much they differ in their advancement.
    I only did mine. And everything works fully automatically.
    The next modifications will be Fantastic Vent, maybe heating and hot water control via bluetooth / SMS. In future inverter air conditioning as soon as there are mobile air conditioners. No one is producing yet.
  • #16
    Jan_Werbinski
    Level 33  
    hostii wrote:

    something for motorhome owners :) although the price does not encourage ....

    I watched it at the fair. An unnecessary gadget for me. With oversized energy solars, it's enough from March to October. Almost nobody is camping in the winter. And if so, the aggregate for 1000 does the trick. Efoy has a price from space. Requires dedicated fuel, which you need to have with you.
  • #17
    hostii
    Level 25  
    Jan_Werbinski wrote:
    Efoy has a price from space. Requires dedicated fuel, which you need to have with you.


    You buy the aggregate exactly and you still have a camper trailer :)
  • #18
    Dll
    Level 1  
    I would like to connect to the topic so as not to duplicate the topic.
    I bought a camper bus and would like to connect pv in addition. Generally, the "la strada" buildings charge two batteries, cars and hotel, I have located a rectifier that works securely as an external 230V connection, there is a 230v converter and ...
    .... such a tin
    The question is, can I connect a solar panel directly here or a panel to the controller and only here?
    I haven't started it yet because it's cold but you have some experience what exactly is it?

    Charging batteries from PV and other sources with simultaneous energy reception. Charging batteries from PV and other sources with simultaneous energy reception.
  • #19
    JESIOTR1
    Level 33  
    Jan_Werbinski wrote:
    It will not exceed the maximum current. Maybe because my battery is almost never fully discharged? If it is heavily discharged and goes e.g. 20A / 240W from solar panels, then after starting the engine and normal driving charging from solar panels decreases e.g. to 100W. It happens automagically and I have never thought about it.

    Such statements and others testify to the lack of knowledge of Ohm's law. First, I recommend classical electrical engineering, and then automation.