Ninian Posted May 24, 2017 Share Posted May 24, 2017 Hi, Currently on site in Spain and permanently on EHU and keeping battery trickled charged with on-board charger its reading 12.5v constantly. Is this showing fully charged ???. Thanks. Link to comment Share on other sites More sharing options...
Keithl Posted May 24, 2017 Share Posted May 24, 2017 No! You will have to turn off or disconnect the charger and then wait at least a couple of hours with no load on the battery before you can measure its 'at rest' voltage. Anything below your 12.5 V and the battery has probably expired. How long has it been on charge and when did you last check its water level (assuming it's not sealed for life)? PS And a charging voltage of 12.5 V is doing no good at all, you need to be seeing at least 13.0 V and probably more like 13.4 V. I think your charger may have expired as well as your battery! Final test, what is the battery voltage with the engine running? Assuming it will start! Keith. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted May 25, 2017 Share Posted May 25, 2017 Ninian The following link contains a battery ‘state-of-charge’ listing http://modernsurvivalblog.com/alternative-energy/battery-state-of-charge-chart/ Its worth noting the caveat (touched on by Keith) "Note: For best accuracy when measuring battery voltage, the battery must be in ‘open circuit’ condition (at rest). This means that the battery must NOT be under load and it must NOT be charging. To be somewhat accurate, the battery should be in that condition for an hour or two before taking a measurement, while for a more accurate measurement you should wait 6 hours up to 24 hours.” If the voltage of a recentish motorhome’s starter-battery is measured (at the battery’s terminals) with the battery connected to the vehicle’s electrical system, there will be some load on the battery as it will be powering certain of the vehicle’s electronics. This load will skew the voltage readings somewhat. You haven’t said how the 12.5V reading is being obtained (eg. are you taking voltmeter measurements at the battery terminals or relying on a control-panel display) but 12.5V sounds like the battery’s state of charge is reasonable but the battery itself is not actually being charged. I believe your Dakota is a 2014 model and I note from the relevant handbook (Pages 19 & 21) https://www.auto-trail.co.uk/assets/downloads/files/f49e1eadd4ed685d3fbe196b27597e258327cb23.pdf that (apparently) charging the starter-battery requires that the motorcaravanner manually select that function via the EC480 control-panel and that there will be an indication on the control-panel as to which battery is being charged. However, I believe that the Sargent EC500 also has a “Smart Charge” feature which may override the need for manual intervention. Anyway, are you certain that, when the readout indicates 12.5V, that the starter-battery is genuinely being charged? Link to comment Share on other sites More sharing options...
Ninian Posted May 27, 2017 Author Share Posted May 27, 2017 Hi, Thanks for the replies, I've contacted Sargent Elect. just for confirmation before I do anything. Link to comment Share on other sites More sharing options...
Charles Posted May 27, 2017 Share Posted May 27, 2017 My guess is the on board charger is off or faulty. Link to comment Share on other sites More sharing options...
Ninian Posted May 27, 2017 Author Share Posted May 27, 2017 Hi, The charger is OK as it charges the leisure batteries with no problem. Link to comment Share on other sites More sharing options...
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