bolero boy Posted February 26, 2020 Share Posted February 26, 2020 I have a 100w solar panel on the roof of the van with a dual channel PWM regulator charging one sealed lead acid starter battery and twin AGM Banner Running Bull 92ah leisure batreries as far as i know, i have the regulator set to provide a split charge of 30/70 in favour of the leisure batteries. the leisure batteries are about 5 years or more old but ive been managing to operate on a site here in Spain without using a mains charger, just relying on the solar panel to provide power for lights, tv, water pump etc. my question is this... using a volt meter the starter battery (which has virtually no draw...no alarm set nor tracker etc) seems be at 14.02v ish all day....not sure what it settles to over night, but not less than 12.8v im fairly confident of... the leisure batteries seem to gradually rise upto 12.8 during the course of the day. perhaps i have a lack of understanding here but i thought i would be seeing a much higher level of charge (14.4v?) from the regulator and this should be visible at both batteries....at some point. i realise the starter battery starts the day 'full' and needs no boost from the regulator and the 14.02v level is some sort of float charge to keep it there? however, with the bias set towards the leisure batteries, why no higher charge level there? if i turn the mains charger on i see the charge level at the leisure batteries rise... with the mix of battery types i have i asked AandN caravans fpr advice on how to set the mains charger, they suggested Gel, which i am using. the cheap PWM regulator has no adjustment thst i know of. if the AGMs arent getting a full charge, for whatever reason, they wont be working at full capacity will they? any suggestest on whether this system is working as it should, given the components, and anything i can do to get more from it....new regulator (MPPT) or change of batteries.....perhaps back to SLA Yuasa EFBs or similar? thanks for any advice.. Link to comment Share on other sites More sharing options...
colin Posted February 26, 2020 Share Posted February 26, 2020 Have you checked the wiring to make sure the batteries are connected to correct outlet? Link to comment Share on other sites More sharing options...
EJB Posted February 26, 2020 Share Posted February 26, 2020 FWIW. When my batteries (Hab and Engine) are full and there is charge from the panel they both read 14+volts and the controller flashes to indicate 'Battery(ies) Full'. Overnight obviously it reduces to a more normal reading. Link to comment Share on other sites More sharing options...
bolero boy Posted February 26, 2020 Author Share Posted February 26, 2020 do you mean have i got the the split right way around? i think so as im sure its 'battery 1' (starter in my case) percentage you set. i am also checking appoximates against a 'motorhome control panel' read out. either way, all charge 'should' go to the 'other' battery onece the first is fully charged shouldnt it? Link to comment Share on other sites More sharing options...
bolero boy Posted February 26, 2020 Author Share Posted February 26, 2020 EJB - 2020-02-26 3:21 PM FWIW. When my batteries (Hab and Engine) are full and there is charge from the panel they both read 14+volts and the controller flashes to indicate 'Battery(ies) Full'. Overnight obviously it reduces to a more normal reading. thanks, yes, thats how my controller works, except that the 14+v is only ever seen on the cab battery (battery 1). for the past 9 days the hab batteries have reached 12.8 (or 12.9) and the light starts flashing, but today on one of the hottest, sunniest weve had, it hasnt reached peak....which is very strange. im wonering if its something to do with the fact that the controller wont (cant) charge AGMs properly? when i turn the mains charger on, i see 14+v at both batteries so im suspecting the solar controller cant do what the mains charger is doing with regard to AGM.? perhaps i need to get the AGMs tested? thanks for the response. Link to comment Share on other sites More sharing options...
spirou Posted February 26, 2020 Share Posted February 26, 2020 It seems unlikely the system would suddenly stop working properly unless you started playing with wires and did them the wrong way round? On the other hand, a 100W panel won't produce a whole lot of charge at this time of year so maybe you're just seeing how the charge isn't keeping up with consumption. Battery age also isn't insignificant when it comes to charge efficiency. When new it can be up to 95% but could drop significantly lower than that with age. So you might need to produce 45Ah to replace 30Ah used or worse. Link to comment Share on other sites More sharing options...
colin Posted February 26, 2020 Share Posted February 26, 2020 What controller do you have? Link to comment Share on other sites More sharing options...
bolero boy Posted February 26, 2020 Author Share Posted February 26, 2020 spirou - 2020-02-26 5:34 PM It seems unlikely the system would suddenly stop working properly unless you started playing with wires and did them the wrong way round? On the other hand, a 100W panel won't produce a whole lot of charge at this time of year so maybe you're just seeing how the charge isn't keeping up with consumption. Battery age also isn't insignificant when it comes to charge efficiency. When new it can be up to 95% but could drop significantly lower than that with age. So you might need to produce 45Ah to replace 30Ah used or worse. im in Spain, its blisteringly hot from 10:30 till 17:00... nothing been 'fiddled with' just checking of the regulator shpuld be showing me a rasised charge of 14.4 or so the AGM leisure batteries... agin, my question is (seems to me) quite simple....on battery 1 (SLA starter battery) i see 14v + bit on the AGM leisure side never more than 13.8 or 13.9v. im sprry i dont know the name of the regulator but ots a generic twin output PWM type 10a AFAIK. Link to comment Share on other sites More sharing options...
colin Posted February 26, 2020 Share Posted February 26, 2020 Battery one is often the leisure battery, you could try changing to give bat1 the higher amount and see what happens. Link to comment Share on other sites More sharing options...
bolero boy Posted February 27, 2020 Author Share Posted February 27, 2020 yes, i might try that but i think i have them the right way as the one with the highest charge (batt 1) also shows as the highest on the control panel with a vehicle symbol....not a leisure symbol. the regulator may have a fault, tne regulator may not be compatible with AGMs and is 'confused'... Link to comment Share on other sites More sharing options...
Paul- Posted February 27, 2020 Share Posted February 27, 2020 If you've checked all the connections on the controller and the battery and haven't found a loose one, I'd consider the earlier phrase " cheap controller" ;-) Link to comment Share on other sites More sharing options...
colin Posted February 27, 2020 Share Posted February 27, 2020 If you are correct about voltage levels I believe your charge controller is wired in wrong, in all dual controllers I've seen bat1 should be the leisure battery, and bat2 should be the starter battery. Companies such as Votronic give specific instructions that bat1 should not be disconnected when panel is producing charge(or switched on if you have a way of isolating it), whilst bat2 can be disconnected, if a vehicle mechanic not familiar with solar set up disconnects the starter battery this can damage the controller. Link to comment Share on other sites More sharing options...
bolero boy Posted February 27, 2020 Author Share Posted February 27, 2020 For info the solar voltage is steady at 15.5-17.5v... i measured the voltages today at the battery terminals as well as at the controller....they were identical at 12.8v which is (just about) fully charged for AGM....however, the controller was showing a solid green light (normal) rather than flashing (full)....so im happy all wiring and fuses are as they should be.....other than the fact that the vehicle battery is Batt 1..... ive had a browse around the net and cant find anything specific about which battery should be connected where. however, i have found 'stuff' which is pretty clear that a cheap PWM controller is unlikely to have the correct charging regime for AGMs and will be undercharging them....which is what im seeing... the charger has been off for nine days or so, so just for a change (and to 'help' the AGMs) i turned on the charger and pretty instantly saw the AGMs sit at the float level of 13.8/13.9 and the cab battery still at 14.02...so there is a further boost to the AGMs that im not seeing with just solar.... as we like to be away from EHU (THS temp hol sites, aires, a bit of wild off grid) looks like my choices are.... 1. change AGMs to 'something else'....Yuasa EFBs rate highly and, being 'normal', my cheap regulator would be more comfortable and keep them more highly charged for longer... 2. change the regulator to more modern MPPT twin channel version that can be programmed for an AGM profile....but would this also be OK for the SLA cab battery? 3. change the regulator to more modern MPPT single channel version that can be programmed for an AGM profile and fit a Battery Master or similar to charge the cab battery? ill be discussing options with local 'solar' guy when we get home but thanks everyone for the help... Link to comment Share on other sites More sharing options...
colin Posted February 27, 2020 Share Posted February 27, 2020 My PWM charge controller was perfectly happy charging the old Banner AGM, although only had the one. The new Varta LFD's don't hold charge anywhere near as good when van is stored under cover, wish I had stuck with AGM's :-( Link to comment Share on other sites More sharing options...
bolero boy Posted February 27, 2020 Author Share Posted February 27, 2020 ok, thats interesting....i know that Allan Evans (AandN caravans and a poster on MMM) dodnt like AGMs much.. :-( Link to comment Share on other sites More sharing options...
spirou Posted February 27, 2020 Share Posted February 27, 2020 PWM or MPPT won't matter much with a single 100W panel. Whether your controller is suitable for AGM (14.8V) s currently irrelevant as it's not even getting them above 14. The first step should be to figure out why and the simplest test is to first cover the panel, then switch the wires between outputs 1 and 2. Do not disconnect batteries when the sun is hitting the panels! This way you can at least eliminate one possible issue. My guess is still on consumption being higher than solar yield and you being in a quite large deficit. 100W panel will stay well below that power for most of the day, while a mains charger is probably closer to 300W and thus much faster to reach 14+ (at least at the terminals if not internally). What happens if you plug into mains for 2 days, unplug at night before you go to sleep, then rely on solar to replace the presumably minimal overnight consumption? If you wish to throw money at the problem, these seem to be very cheap and have dual output models with all relevant charge profiles https://www.olyssolar.com/m/Product_List.aspx?classId=3&T_State_cn=4 Link to comment Share on other sites More sharing options...
bolero boy Posted February 27, 2020 Author Share Posted February 27, 2020 spirou - 2020-02-27 5:26 PM PWM or MPPT won't matter much with a single 100W panel. Whether your controller is suitable for AGM (14.8V) s currently irrelevant as it's not even getting them above 14. The first step should be to figure out why and the simplest test is to first cover the panel, then switch the wires between outputs 1 and 2. Do not disconnect batteries when the sun is hitting the panels! This way you can at least eliminate one possible issue. My guess is still on consumption being higher than solar yield and you being in a quite large deficit. 100W panel will stay well below that power for most of the day, while a mains charger is probably closer to 300W and thus much faster to reach 14+ (at least at the terminals if not internally). What happens if you plug into mains for 2 days, unplug at night before you go to sleep, then rely on solar to replace the presumably minimal overnight consumption? If you wish to throw money at the problem, these seem to be very cheap and have dual output models with all relevant charge profiles https://www.olyssolar.com/m/Product_List.aspx?classId=3&T_State_cn=4 spirou, thanks for that...i can pull the solar panel fuse to save covering the panel? ive not pulled the fuse previously but have run with the charger for a bit and then returned to solar only... from memory i thing it did return the batteries to full power (flashing light) for a few days but just lately (since the fifth or sixth day) they havent been coming back up fully... i can see what you're saying about consumption deficit but we only have lights on (all LED) for a couple of hours along with a 12v tv...water pump only for loo flush, no long showers all in the shower block. i would have found it hard to believe that a 100w panel in this level of sunshine couldnt replace that.... im sure weve done days on end in the uk with the addition of showering in the van and the panel has kept up... perhaps the batteries are goosed? Link to comment Share on other sites More sharing options...
spirou Posted February 27, 2020 Share Posted February 27, 2020 Yes, you can also pull the fuse to disconnect the panel. It is entirely possible batteries are bad but there would probably be other symptoms as well. Most likely by voltage dropping fast under load. No reason not to perform some tests before you go out and buy anything. Link to comment Share on other sites More sharing options...
bolero boy Posted February 28, 2020 Author Share Posted February 28, 2020 thanks, ive got plenty of time here and am not short of power, one way or another, so will turn off again tonight and see what happens re solar refresh on the following morning... last time i did this i think the batteries were still 'full' first thing and so the solar didnt need to do anything. however, its the lack of a 'higher' float charge on the leisure side thats the mystery....even if the solar cant keep up (this may be right or wrong) the panel should be raising the charge to at least 14.02v as it is on the vehicle battery side. ill get round to swapping regulator outputs sometime...which might indicate an issue on the 'Batt 2' side....however, if it does, i wont want the vehicle battery to be gradually losing charge so might need to swap back but would highlight any regulator issues. cheers. Link to comment Share on other sites More sharing options...
colin Posted February 28, 2020 Share Posted February 28, 2020 If the starter battery is kept at 12.8v by the controller that will be fine. Link to comment Share on other sites More sharing options...
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