Nigel P Posted October 2, 2023 Share Posted October 2, 2023 We have a new to us a 2009 Autotrail Mohican. It has a Sargent EC 328 controller, with two 110 amp leisure batteries that are almost one year old. Prior to going away for Saturday night, I hooked the van up to the mains to ensure that the leisure batteries were fully charged. ( the Sargent said 12.2 prior to hooking up the van.) After having it hooked up to the house mains for about 12 hours or so, at rest they showed 12.9 on the Sargent. After just one evening using the interior lights (LED's), and the Trumatic heater fan for 40 minutes, we woke to find that the Sargent was showing 12.2 in the morning, but it didn't drop below that for the rest of that day. ( no power switched on). Is it normal for the Sargent to show its as low as that after one night of use? The van is now back home and is showing between 12.4 and 12.5 on the Sargent, having been sat on the drive since Sunday when we got back. So I'm assuming it's the Solar panel that's topping it up. So my questions are, Is it normal to drop to 12.2 on the Sargent after one night use? Would it take longer than the 12 hours or so I had it hooked up to the mains to top up the two leisure batteries from 12.2 showing on the Sargent, ie could it have dropped so quickly because I maybe hadn't put a full charge in? How long is it safe to leave it hooked up to the mains to ensure the batteries are fully charged if everything is turned off? Thanks I advance Nige Quote Link to comment Share on other sites More sharing options...
Nigel P Posted October 2, 2023 Author Share Posted October 2, 2023 (edited) Since I posted that 45 minutes ago, the Sargent is now showing the leisure batteries at 12.3 V, having dropped from the 12.4/12.5 previously Edited October 2, 2023 by Nigel P Quote Link to comment Share on other sites More sharing options...
david lloyd Posted October 2, 2023 Share Posted October 2, 2023 Nigel if you are not seeing anything above 12.5v on the panel with either the solar panel or mains charger operating then it suggests neither are charging the batteries. However, it would be wise to check those voltages at the battery terminals with a multimeter in the first instance - it could be the panel that is not showing the correct voltage. Even in this fairly dull day my two 105ah batteries are showing 13.2v without EHU just from the 100W solar panel which is sitting underneath a clear roofed carport. If the voltage at the battery terminals is the same as the panel I would then try running the engine and check the leisure battery voltage again - this should now be showing something like 14.2v - 14.4v with the alternator charging. If that happens it does suggest a problem with the Sargent charger. David 1 Quote Link to comment Share on other sites More sharing options...
Nigel P Posted October 2, 2023 Author Share Posted October 2, 2023 1 hour ago, david lloyd said: Nigel if you are not seeing anything above 12.5v on the panel with either the solar panel or mains charger operating then it suggests neither are charging the batteries. However, it would be wise to check those voltages at the battery terminals with a multimeter in the first instance - it could be the panel that is not showing the correct voltage. Even in this fairly dull day my two 105ah batteries are showing 13.2v without EHU just from the 100W solar panel which is sitting underneath a clear roofed carport. If the voltage at the battery terminals is the same as the panel I would then try running the engine and check the leisure battery voltage again - this should now be showing something like 14.2v - 14.4v with the alternator charging. If that happens it dies suggest a problem with the Sergent charger. David David, thanks for the reply, when hooked up to the mains, it shows 14.3 volts charging. When not hooked up, it shows a charge on the Sargent of 0.3 to 0.4 V which I'm assuming is the Solar panel. I can't check the charge on the Sargent with the engine running, but if you run it for 5 minutes or so, it does show that a charge has been put in when the engine's stopped, though it does drop down after the batteries have settled. Quote Link to comment Share on other sites More sharing options...
david lloyd Posted October 2, 2023 Share Posted October 2, 2023 It’s still worth checking the voltage at the battery terminals just to rule out any discrepancy between them and the reading on the panel - depending on size of cable, length of cabling etc it’s often the case that there is some voltage drop to the panel but 12.2 does seem low. David 1 Quote Link to comment Share on other sites More sharing options...
Labby Posted October 2, 2023 Share Posted October 2, 2023 (edited) If you find , when checked , that the actual voltage at the battery terminals is different to that shown at the control panel it may be that the control panel needs re calibrating , the details on how this is done can be found in the EC328PSU manual or from www.sargentltd.co.uk in its support section Edited October 2, 2023 by Labby 1 Quote Link to comment Share on other sites More sharing options...
Nigel P Posted October 3, 2023 Author Share Posted October 3, 2023 Would it take longer than the 12 hours or so I had it hooked up to the mains to top up the two leisure batteries from 12.2 showing on the Sargent, ie could it have dropped so quickly because I maybe hadn't put a full charge in? How long is it safe to leave it hooked up to the mains to ensure the batteries are fully charged if everything is turned off? Cheers...Nige Quote Link to comment Share on other sites More sharing options...
cid Posted October 3, 2023 Share Posted October 3, 2023 Hi Nigel P, If you were away on holiday on a site, I presume, your hook up would be permanently on. Therefore, it should be safe to leave it on at home unless the charger is faulty. All the Best, Ian. Quote Link to comment Share on other sites More sharing options...
Keithl Posted October 3, 2023 Share Posted October 3, 2023 20 minutes ago, Nigel P said: Would it take longer than the 12 hours or so I had it hooked up to the mains to top up the two leisure batteries... Yes, almost certainly. If you were discharged to say 50% then you would need to add 2 batteries x 110 Ah x 50% = 110 Ah of power to fully charge. If your charger was outputting say 5 A then they would take 110 / 5 = 22 hours to fully charge. But in reality the rate of charging falls off as they get nearer fully charged so I would say an absolute minimum of 24 hours, and probably more like 48 hours to make sure. I regularly (at least once a month) charge my single 95 Ah battery for 48 hours to keep it topped up. Keith. Quote Link to comment Share on other sites More sharing options...
david lloyd Posted October 3, 2023 Share Posted October 3, 2023 25 minutes ago, Nigel P said: Would it take longer than the 12 hours or so I had it hooked up to the mains to top up the two leisure batteries from 12.2 showing on the Sargent, ie could it have dropped so quickly because I maybe hadn't put a full charge in? How long is it safe to leave it hooked up to the mains to ensure the batteries are fully charged if everything is turned off? Cheers...Nige Nigel, yes as Keith says it would take much longer to fully charge two 110ah batteries. If your mains charger is charging at 14.3v (this would eventually reduce over the charging period) then it seems to be working. However, you say the solar panel alone only shows a charge of 0.3 - 0.4v even without full sun that may indicate a faulty panel or regulator. If the batteries were not fully charged when you set off and you relied sole on that level of solar output then you wouldn’t get much out of the batteries. Similarly, if the alternator is not putting in a sufficiently high voltage whilst driving then it would have the same effect - hence the need to check a) the voltage AT THE LEISURE BATTERY TERMINALS with the engine running and b) the voltage at the solar panel regulator. David Quote Link to comment Share on other sites More sharing options...
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