Tall_Mike Posted April 13, 2017 Share Posted April 13, 2017 Hope this isn't a silly question, I am a little curious - Following the good advice given via this forum we have had a Solar Panel Professionally fitted by a reputable company, along with the dual regulator and it's working very nicely for us - Batteries are always fully charged, and when out and about (now the sun is shining) the load that we take out over the evening is quickly replaced in few hours. The calculations about usage were correct and as far as I know we have no problems My question is - When both the Leisure Battery and the Engine Battery are full, - I know the Schauld unit goes into a re-cycling mode, draining and topping up at a low level, but what happens to the surplus charge, - If anything we have too much. - How does the regulator turn off the Panel or slow it's charging rate without producing heat - Link to comment Share on other sites More sharing options...
StuartO Posted April 13, 2017 Share Posted April 13, 2017 The Schaudt Electroblok limits the charge going into the batteries (separately) by limiting the voltage which is applied to them. The Solar Regulator limits the voltage which reaches the Electroblok to a manageable level so it can then fine tune the voltage applied to the batteries to optimise charging. Neither Regulator nor Electroblok use resistance to do this these days, it's done by clever electronic switching, so there is no need to "dump" surplus energy by using resistors and generating heat, the unwanted electricity never even leaves the panels. If you measure the output voltage of the solar panels on a bright day it might be as high as 25 volts, the Regulator feed under 15 volts to the the Electroblok which then limits the voltage applied to the batteries toa lower figure according to their needs and type. Once charging is completed, the Electroblok will maintain a final "float" voltage of 13.8 to as little as 13.2 volts, depending on the battery type. Sleep soundly and relax, feeling smug; your Schaudt system is continuously looking after your batteries for you. Link to comment Share on other sites More sharing options...
aandncaravan Posted April 13, 2017 Share Posted April 13, 2017 In very basic terms, not Technically correct, but a good way to understand it, a PWM Solar Regulator places a big load on the Solar Panel to draw off all the power it can deliver. It does this in response to the demand from the battery. The lower the battery demand, the lower the load the regulator places on the Panel. Because the regulator only takes what it needs, there is little excess. The problem with a PWM regulator, like the Lr1218, is that the load it places on the Panel in low light conditions can lead to the Panel voltage dropping to below the battery voltage (the charge voltage must be higher than the battery voltage for current to flow, even if there is 2 amps 'in the Panel') resulting in no charge. A MPPT regulator varies it's demand on the Panel so that the voltage is always above that of the battery, hence it working better in low light conditions. In conditions of full, high sun an MPPT and PWM will deliver pretty much the same power. Some PWM's outperforming an MPPT slightly. You write that, " the load that we take out over the evening is quickly replaced in few hours". This may be correct in your case, but many people monitor the voltage at the battery and see it rise up to 14v fairly quickly so assume the battery is now fully charged, when the battery may actually be at 11.5v". Because it is not possible to 'see' the actually battery voltage once the Solar Regulator is applying it's 14.2v charge voltage, many people underestimate the power 'loss'. A volt meter can only display the voltage at the battery, which may not be the battery voltage, This can lead to a battery that very slowly has more taken out of it than is put back, hence our advice on the Solar pages to monitor actual power taken out and put back by something like the £12 device shown on the pages : http://www.aandncaravanservices.co.uk/solar-power.php See Section 2. All good professional installs now install such a display (if it isn't already built in like it is on the EBL 220, etc.) to help you monitor the Solar panels true effectiveness. I am not saying this is happening in your case, just putting it here for others who read the thread. Note that the LR1218 is a battery charger, not a battery maintainer, and like most pre 2016 designed Solar regulators is designed to continually feed the batteries with a charge voltage, even when they don't need it. It is best isolated during long periods of 'none-use'. If you have the new LRM 1218, it drops it's maintenance voltage down to 13.3v/13.4v so it's impact on the battery long term 'storage' will be less. Not sure what you mean by, "I know the Schauld unit goes into a re-cycling mode, draining and topping up at a low level"?? Where have you got that information from, as I have not seen that written anywhere before? , Link to comment Share on other sites More sharing options...
Alanb Posted April 14, 2017 Share Posted April 14, 2017 aandncaravan - 2017-04-13 11:37 AM A volt meter can only display the voltage at the battery, which may not be the battery voltage, My apologies to Allan, but I think that he will be losing some of our less electrically minded friends with the above sentence. May I explain for their benefit. A battery has internal resistance, although this is low it has an effect on the terminal voltage. A battery can be considered as a perfect battery in series with a resistance. It is the sum of the perfect battery voltage, plus the voltage drop created by the charging current flowing through the resistance, that is seen at the battery terminals. Perhaps more important, is the effect of surface charge on the battery plates pushing the battery voltage up. Link to comment Share on other sites More sharing options...
aandncaravan Posted April 14, 2017 Share Posted April 14, 2017 Sorry, But I don't think that adds anything at all? If I connect my 11.2v battery to a Solar 14.4v charger, I am no longer able to see the batteries true charged state, only the charging 14.4volts. All I am able to see, no matter which way I hold the voltmeter, is the 14.4v Solar charge, the true battery condition is still a discharged 11.2v battery. If I immediately disconnect the 14.4v Solar charge (where some 'seeing' 14v on the gauge might believe the battery has reached full charge) it will quickly drop back to it's 11.2v discharged state. The point of my comment above, was that, just because the battery gauge is showing a high voltage, does not mean that is the voltage of the battery for determining it's charge state. Link to comment Share on other sites More sharing options...
arthur49 Posted April 14, 2017 Share Posted April 14, 2017 aandncaravan - 2017-04-14 7:41 PM If I connect my 11.2v battery to a Solar charger, I am no longer able to see it's true charged state, only the charging 14.4volts. All I am able to see, no matter which way I hold the voltmeter, is the 14.3v Solar charge, the true battery condition is still a discharged 11.2v battery. If I immediately disconnect the 14.3v Solar charge (where some 'seeing' 14v on the gauge might believe the battery has reached full charge) it will quickly drop back to it's 11.2v discharged state. The point of my comment above, were that, just because the battery gauge is showing a high voltage, does not mean that is the voltage of the battery for determining it's charge state. If you know a clever way of being able to see the true charge state voltage of a discharged battery that is being charge, then I would love to know how I apply my voltmeter to read that? Well I got your meaning first time round Allan .......... and I am no expert .... :-D Link to comment Share on other sites More sharing options...
aandncaravan Posted April 17, 2017 Share Posted April 17, 2017 Over the holiday someone has challenged the above in an email, saying that their Solar setup DOES get the battery up to full charge by 10:00, because the Solar Regulator has dropped to a 13.8v float charge, which they think it will only do when the battery is fully charged. This is not always the case. Almost all Motorhome mains chargers, charge at the initial 14.4v rate for a set timer period, such as 4 hours, NOT until the battery is fully charged. The battery may only be 70% charged, but if the 4 hour 'Initial charge' timer has expired it will drop to 13.8v float and continue charging at a much slower rate. This is also how many Solar regulators work. For an example of this operation see the chart below showing that an older Schaudt EBL 100 will charge a wet battery at 14.3v for just 1 hour before dropping to 13.8v. A more detailed explanation here : http://www.aandncaravanservices.co.uk/how-does-a-charger-work.php Each Solar set-up is likely to have a unique element so each person might be advised to find out how their Solar Regulator actually works? Link to comment Share on other sites More sharing options...
Brambles Posted April 17, 2017 Share Posted April 17, 2017 During stage 1 the battery will charge until the voltage reaches 14.3 volts, with the max charge current current being limited. This stage will take as long as it takes. This supplies the bulk of the charge and will be around 90 to 95% charged, Then the 14.3 volts is held and the charge current falls. After 1 hour, or in some cases say 4 hours, of reaching 14.3 volts the charger will switch to trickle or maintenance charge of 13.8 volts. So it is indeed correct to assume if the voltage has fallen back to 13.8 volts then the battery is in effect fully charged. In the example listed above by Allen, a Gel Battery setting maintains the 14.3 volts for 8 hours if you read the notes.This is because it takes a Gel battery a long time to get the final few percent of charge into it. Link to comment Share on other sites More sharing options...
aandncaravan Posted April 18, 2017 Share Posted April 18, 2017 The Voltage at the battery reaches 14.3volts in minutes, even on a 50% discharged battery. The timer then starts and puts out the initial charge till the timer expires. Only if the battery is in an over discharged or damaged state do they take a bit longer to reach 14.3v Chargers like the Nordelettronica NE143_MH will hit 14.4v and close on 18amps in seconds. The timer generally starting at the same time. Are you confusing the battery voltage with the voltage at the battery? Link to comment Share on other sites More sharing options...
Brambles Posted April 18, 2017 Share Posted April 18, 2017 aandncaravan - 2017-04-18 12:50 AM The Voltage at the battery reaches 14.3volts in minutes, even on a 50% discharged battery. The timer then starts and puts out the initial charge till the timer expires. Only if the battery is in an over discharged or damaged state do they take a bit longer to reach 14.3v Chargers like the Nordelettronica NE143_MH will hit 14.4v and close on 18amps in seconds. The timer generally starting at the same time. Are you confusing the battery voltage with the voltage at the battery? It will only reach 14.3 volts quickly if you supply enough current, this will be above the recommended charge current and will damage the battery reducing its life significantly. Also the solar panel will not be able to supply enough current therefore the charge voltage will rise slowly. I take it you mean charge voltage and rest voltage , if so I am not confused. If you do not mean this then yes I am totally confused what you are talking about. Link to comment Share on other sites More sharing options...
aandncaravan Posted April 18, 2017 Share Posted April 18, 2017 Sorry Brambles but you are talking theory, not reality, even then your figures are well out. You also seem to be talking about an over discharged battery (discharging down to damaging levels) not normal Motorhome/caravan use. A battery discharged to an ideal level will happily take the full current it wants and voltage. A perfect demonstration of this happens when you start the engine, the Alternator battery CHARGER takes a 12.3v battery voltage straight up to 14.4v and starts throwing in maximum current. It doesn't start off at 12.2v slowly rising up and slowly increasing current. A mains or any other charger can do the same. If it has the power it will raise the voltage at the battery pretty quickly, even if the battery is down at a 'real' 12.3v. That is the fastest way of charging a battery, to get the battery terminals at 14.4v as quickly as possible, exactly as an Alternator does. Wikipedia ( https://en.wikipedia.org/wiki/IUoU_battery_charging ) notes that the first stage may get the battery up to 70% charge in the first stage, well below your 95% figure. As 70% also corresponds to the the optimum maximum discharge recommended by all battery manufacturers for maximum life, many Motorhomers will be starting their charger at this figure and as Wiki notes the Charger may go STRAIGHT to the second stage. Wiki writes, "Once the Umax voltage is reached, typically when the battery is charged to 70–80% of its capacity, the charger enters the Uo-phase. In case of a battery that is more than 80% full, this may happen immediately once the charger is switched on". But that's the 'theory'. In reality quality Motorhome Leisure battery chargers on a quality battery will reach 14.3v at the battery terminals very quickly, even on a maximum 50% discharged battery. It will then switch on the timer within minutes, even if the 'true' battery voltage is as low as 12.3v. Many people misread the IUoU chart thinking it is talking about the battery voltage when it is the voltage at the battery that the charger uses for sensing, which can obviously be a completely different thing as the Charger can throw 14.4v into the battery terminals even when the 'true' battery voltage is much lower. And yes, even when a battery is taken down to 50% discharge most chargers we have seen will apply maximum current (until the charger gets hot and backs down to protect it) not the slow rise you seem to think will happen. Only when a battery is over discharged, is faulty or the charger has a issue will the current be anything else. But remember all sorts of other factors change the theory in the real world, like temperature : A charger will perform much better at zero degrees than it will at 40 degrees. A battery that is a year or two old can also completely skew the figures. The charts are Laboratory conditions with new batteries, new chargers (usually lower power than a Motorhome) and ideal temperatures. In the real world, batteries rarely perform as many 'laboratory tests' show. I think you have Varta LFD90 batteries so suggest you discharge them down to 12.7v (the recommended 70% charged) and turn on the mains charger. If everything is healthy you should see the voltage at the battery rise to 14.3v within minutes, when the 1 -4 hour timer will start. If you set your stopwatch you will see it drop to 13.8v when the timer expires, but I would expect your 2 batteries to still be well under full. Typically the charger will start off at about 16amps but this will quickly drop as the charger heats up averaging about 8 - 10 amps for those 4 hours, clearly not putting back the 60Ah taken out. Link to comment Share on other sites More sharing options...
Brambles Posted April 18, 2017 Share Posted April 18, 2017 Even wilkipedia.... Oh how things get miss quoted. Information is based on a Samlex manual for a high power charger.. quote: SEC-1260A/SEC-1280A (for 12 V batteries) and SEC-2440A (for 24 V batteries) are high current, 3 Stage Chargers that deliver 60 A, 80 A and 40 A respectively for almost 75% to 80% of the charging cycle ensuring a very fast, safe and complete charging of lead acid batteries. 75% of the charge cycle does not mean 75% charged it means 75% of the cycle total time. It takes a long time to put the last 10% in !!! Anyway I will let you do the test you suggested as I know my batteries take hours to get through the 1st stage to reach 14.4 volts and cut back. Link to comment Share on other sites More sharing options...
aandncaravan Posted April 18, 2017 Share Posted April 18, 2017 Brambles, The IU0U is a standard for chargers and how they work regardless of size. You write, " 75% of the charge cycle does not mean 75% charged it means 75% of the cycle total time. It takes a long time to put the last 10%". You are quoting the manual itself, which I wasn't. I was quoting the Wiki generic description for a charging standard that applies to all such chargers. Wiki definitely states, "Once the Umax voltage is reached, typically when the battery is charged to 70–80% of its CAPACITY". The Waeco charger manual I have been looking at, quite an advanced/new unit, states, " U0 Phase - Now the time that limits the MAIN charging...". This is the phase where charging of the main/usable part of the battery takes place. As I said before if your set-up takes a long time reaching 14.3v then you are over discharging them or you have an issue somewhere? I think we should agree to disagree, otherwise it will end up running like the big saga we had over Powerframe batteries some years back. Link to comment Share on other sites More sharing options...
Brambles Posted April 19, 2017 Share Posted April 19, 2017 Whatever, I am in no mood to discuss this further and convince you the wikipedia contributor has misquoted the source he got the information which I pointed out above. As to me over discharging my batteries - I do not, I know how to manage battery power and maximise the life of a battery. All I was attempting to do was highlight a few errors in your excellent post but clearly I am muddying the waters for you so I will shut up now. Edit - spelling! Link to comment Share on other sites More sharing options...
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