Crabber One Posted December 3, 2019 Share Posted December 3, 2019 Hi All, My wife and I have a 2004 Hymer B614. I am proposing to add (a) solar panel(s) to the roof with the hope that I can charge the 2 x 90Ah Varta LD90s (in parallel) leisure batteries as well as keeping the 90Ah starter battery (Bosch S3) topped up in periods of inactivity. The MH is fitted with an EBL100 connected to a DT200 display. My intention, after a limited amount of research (on this forum and others), was to install the Schaudt LRM1218 close to the EBL100 and run cabling to a single 270W solar panel. On purchasing the LRM1218 I am now aware that, whilst it can take a solar panel to ~270W, the open charge voltage is likely to exceed that accommodated by the LRM1218 in certain conditions. I have been advised to purchase 2 x 120W solar panels instead and wire them in parallel to the LRM1218. 1. Will this setup charge the leisure batteries to an adequate voltage and then move on to charge the starter battery? 2. Will I see the charging voltage and current on the DT200 display? 3. If I replaced the LRM1218 with a Votronic MPP350 Duo can I (simply) wire this up to the EBL100 and achieve the same result and with a single 275W panel? Thank you all in anticipation. Kind regards, John Link to comment Share on other sites More sharing options...
spirou Posted December 3, 2019 Share Posted December 3, 2019 With regard to single vs dual solar panels it doesn't really matter much. From the regulator onwards they behave exactly the same. Before the regulator you get to choose whether to wire panels in series or parallel. Both have pro/con. Series will in theory start producing useful charge earlier in the morning and at lower light levels but is more sensitive to partial shading. My logic is that I need the panels more in winter when lower light levels favor the series wiring. That said, it's not going to produce much anyway, a few % of the nominal power.. In the summer, when I'm more likely to park in the shade, I figure the cons are largely irelevant as there is more than enough light to cover lower consumption. How and what happens after the regulator in your case with EBL100 is an area I'm not familiar with. If it has a solar input and you can monitor what goes in and out of the battery, then it makes sense to wire that way. I believe votronic regulators are also compatible with Schaudt EBL. Just check first if there are any power limits for solar through EBL. Whether LRM or Votronic wired this way will charge the starter battery depends entirely on the EBL. Schaudt has a catalog of manuals and it is definitely worth reading through them to find out specifics. As far as I know the LRM does not itself have dual charging, so if EBL doesn't support it you need to go with votronic and use it to wire into starter battery separately. That said, I find there is very little if any draw on starter battery when stationary (X250 & X290 generations). Unless you have an alarm or any other equipment draining the starter battery, it might not be worth the trouble. Link to comment Share on other sites More sharing options...
747 Posted December 3, 2019 Share Posted December 3, 2019 It sounds like you have bought a solar panel intended for use on the roof of a house and not suitable for a motorhome installation. You can buy solar regulators that can handle higher input voltages but they are not cheap (and you already have a very good one in the Schaudt LRM). Probably best to get 2 other panels. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 4, 2019 Share Posted December 4, 2019 This advert for a 270w panel describes it as being suitable for motorhomes https://www.alpha-batteries.co.uk/12v-270w-xplorer-german-cell-solar-panel/ (I don't think John has committed yet to which panel(s) to purchase.) Link to comment Share on other sites More sharing options...
spirou Posted December 4, 2019 Share Posted December 4, 2019 The issue is the open circuit voltage limit which is 32V for the LRM1218, and the panel linked above will go to 36V at standard temperature, which could easily mean close to 40V below freezing. With such low Voc limits on the LRM1218 you don't really have any other option than parallel wiring whatever size panels you choose. With the Votronic 350 the Voc limit is 50V so you can do either (up to a point but 2 regular panels should work). The other thing to consider is the available space and panel dimensions. There is no "caravan" vs "house roof" specific panel, but there's rarely enough space for a classic 300W panel on the roof of a MH hence the more usual 80-160W range. Link to comment Share on other sites More sharing options...
747 Posted December 4, 2019 Share Posted December 4, 2019 If you follow advice and go for the 2 smaller panels, these are on offer with Sunshine Solar. https://www.sunshinesolar.co.uk/Item/SSP130M Link to comment Share on other sites More sharing options...
Crabber One Posted December 4, 2019 Author Share Posted December 4, 2019 HI Spirou, Thank you for your very helpful reply. I have already ordered the LRM1218 and the question was really whether there was enough benefit to go through the process of exchanging it for a Votronic as the price is similar. I agree that there is very little discharge from the starter battery and I may use a portable solar panel for the winter months to keep it charged up especially when alarmed. It seems that 2 x 120W should be sufficient for our needs if the wife leaves her hairdryer at home. Many thanks, John Link to comment Share on other sites More sharing options...
Crabber One Posted December 4, 2019 Author Share Posted December 4, 2019 Hi Jim, Thanks for your reply. I haven't bought the panels as yet and I was looking on the Photonic Universe website. Both the 300W and the 2 x 120W rigids are suitable for a motorhome. I have discounted the lighter semi-flexibles on account of reports of their high failure rate. I think I will end up sticking with the LRM1218 and buying 2 x 120W or 2 x 130W panels and we shall see how I get on. Thanks again for your help Jim, Regards, John Link to comment Share on other sites More sharing options...
Crabber One Posted December 4, 2019 Author Share Posted December 4, 2019 Derek Uzzell - 2019-12-04 11:55 AM This advert for a 270w panel describes it as being suitable for motorhomes https://www.alpha-batteries.co.uk/12v-270w-xplorer-german-cell-solar-panel/ (I don't think John has committed yet to which panel(s) to purchase.) Hi Derek, Thank you. This sounds like a similar panel to what I was looking at but at a much better price. I am however tending towards the 2 x 120-130W panels and I shall see how I get on. Thank you very much for your help and I suspect that this will not be the last time I turn to this forum for assistance. Kind regards, John Link to comment Share on other sites More sharing options...
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