rooster63 Posted August 28, 2018 Share Posted August 28, 2018 My van starter battery has something that causes it to fall to below enough volts to start the engine if left for more than about a week. Have had an electrician look at it and he couldn't explain what was draining it, maybe the after fit alarm. Am going to away (not in the van) for over 2 weeks and trying to decide on the best option. The battery is only a year old and using the onboard control panel with the engine running voltmeter is showing 14.2V so charge is going in. With engine off usually drops down to about 12.8V and then after 4 or 5 days 12.4V and then 12v 1) Leave things off the EHU and on return connect a trickle charger, if I do this will the battery suffer any damage, I assume there will still be enough juice for the alarm. 2) Leave the battery on charge with an intelligent (CTEK) trickle charger, as the EHU will have to be connected this will also mean the leisure battery is getting a charge but again this is from an intelligent charger. Is there any danger of the batteries being over charged and maybe overheating? I'm not sure if the charger for the leisure battery is switched off whether the 240V sockets remain live for the starter battery charger to get power. 3) Connect the EHU via a timer snd set it to come on maybe 6 hrs per day. Any thoughts on best option? Link to comment Share on other sites More sharing options...
spirou Posted August 28, 2018 Share Posted August 28, 2018 3) is the simplest solution to a one time problem Long term, figure out what is causing the drain (alarm being the obvious suspect), how big is the drain and continue from there. Link to comment Share on other sites More sharing options...
aandncaravan Posted August 28, 2018 Share Posted August 28, 2018 rooster63 - 2018-08-28 11:44 AM 1) Leave things off the EHU and on return connect a trickle charger, if I do this will the battery suffer any damage, I assume there will still be enough juice for the alarm. 2) Leave the battery on charge with an intelligent (CTEK) trickle charger, as the EHU will have to be connected this will also mean the leisure battery is getting a charge but again this is from an intelligent charger. Is there any danger of the batteries being over charged and maybe overheating? I'm not sure if the charger for the leisure battery is switched off whether the 240V sockets remain live for the starter battery charger to get power. 3) Connect the EHU via a timer snd set it to come on maybe 6 hrs per day. Any thoughts on best option? 1. Yes, damage can begin when a typical starter battery starts dropping below 12.3v 2. Intelligent chargers are more dumb than you might think. But for short term EHU, like weeks at a time, it's not an issue, but months will be. 3. A good longer term option, but because you are only talking short term, if it was me I wouldn't bother with the timer, so long as you are sure the batteries are good. Link to comment Share on other sites More sharing options...
rooster63 Posted August 28, 2018 Author Share Posted August 28, 2018 Have found that my Rovert charger has a switch so that the charger can be just a psu so will plug in my CTEK smart charger to the campervan mains and just charge the starter battery as the leisure battery doesn't seem to lose any charge. Had a vehicle electrician give the once over the electrics, can't remember what the drain was, I think about 3 times what it should be, hence the starter battery only lasting about a week. He couldn't pinpoint the source so he suggested wiring the connectors supplied with the CTEK to the terminals for the starter battery on the distribution board (in theory the EHU charger is supposed to charge the starter battery once the leisure battery is fully charged but the relay to trigger that was never installed) so that I have easy access to connect the charger. Don't have to lift the bonnet or take the panel covering the battery which is under the passenger footwell. Link to comment Share on other sites More sharing options...
snowie Posted August 28, 2018 Share Posted August 28, 2018 Disconnect the battery and nobody will be able to nick the van anyway, and alarm won’t drain the battery, Simple? Regards, Snowie Link to comment Share on other sites More sharing options...
aandncaravan Posted August 28, 2018 Share Posted August 28, 2018 rooster63 - 2018-08-28 3:57 PM Have found that my Rovert charger has a switch so that the charger can be just a psu so will plug in my CTEK smart charger to the campervan mains and just charge the starter battery as the leisure battery doesn't seem to lose any charge. Had a vehicle electrician give the once over the electrics, can't remember what the drain was, I think about 3 times what it should be, hence the starter battery only lasting about a week. He couldn't pinpoint the source so he suggested wiring the connectors supplied with the CTEK to the terminals for the starter battery on the distribution board (in theory the EHU charger is supposed to charge the starter battery once the leisure battery is fully charged but the relay to trigger that was never installed) so that I have easy access to connect the charger. Don't have to lift the bonnet or take the panel covering the battery which is under the passenger footwell. It is actually quite easy to trace current drain on the Starter battery, you just need a £6 Clamp meter from eBay (or wherever) like this one : https://www.ebay.co.uk/itm/LCD-Digital-Multimeter-Auto-Handheld-Clamp-Meter-Volt-AC-DC-600-Amp-Tester-UK/153133717650?hash=item23a77b1892:m:mnfNly9eXyPTOnoqkScWgyw Don't expect it to be accurate or great, but it doesn't need to be. Set the meter to the 20amp range and Clamp it onto the Starter battery cable. Then locate all the vehicle (not habitation) fuse boxes and remove each fuse, one at a time only, and watch the meter looking for any current drop. Replace each fuse as you go. Record ANY current drop with fuse and drop seen. When you have finished there are likely to be a few fuses with details of what they power on your list, not just a single offender. That should give you enough info to decide what to do. As a temporary measure, just remove the fuse that is the key offender and replace it whenever you need to use the vehicle. Link to comment Share on other sites More sharing options...
plwsm2000 Posted August 28, 2018 Share Posted August 28, 2018 Allan, In spite of its description, I'm not sure if that particular model of current clamp meter will measure dc current. The spec only says AC current (but it measures dc voltage). Many current clamps use a transformer principle to measure ac currents and transformers don't work at dc. DC clamps use either a hall effect or magnetoresistive sensor to measure the magnetic field around the wire that is generated by the current passing through it. They are a bit more complicated and therefore usually a bit more expensive. If you are trying to measure small currents, you may find that the magnetic field around the wire is not far off that of the earth's magnetic field and so the orientation of the clamp can affect the measurement. I would check the spec says dc current, and it is measured by the clamp (not by breaking the wire and measuring the current in the same way as a simple dmm) Link to comment Share on other sites More sharing options...
plwsm2000 Posted August 28, 2018 Share Posted August 28, 2018 I would also be a bit wary of using a timer to switch on the ehu for 6 hours a day as most chargers will attempt to fast charge the leisure battery, and if it is not being used much, you risk overcharging it. I agree that !eaving it on a permanent ehu until the problem is sorted is probably the better option. Link to comment Share on other sites More sharing options...
Barryd999 Posted August 28, 2018 Share Posted August 28, 2018 snowie - 2018-08-28 4:22 PM Disconnect the battery and nobody will be able to nick the van anyway, and alarm won’t drain the battery, Simple? Regards, Snowie Thats what I do. I Dont have an alarm though anyway. Link to comment Share on other sites More sharing options...
aandncaravan Posted August 28, 2018 Share Posted August 28, 2018 plwsm2000 - 2018-08-28 11:32 PM Allan, In spite of its description, I'm not sure if that particular model of current clamp meter will measure dc current. The spec only says AC current (but it measures dc voltage). Many current clamps use a transformer principle to measure ac currents and transformers don't work at dc. DC clamps use either a hall effect or magnetoresistive sensor to measure the magnetic field around the wire that is generated by the current passing through it. They are a bit more complicated and therefore usually a bit more expensive. If you are trying to measure small currents, you may find that the magnetic field around the wire is not far off that of the earth's magnetic field and so the orientation of the clamp can affect the measurement. Thank you, I didn't spot that, just looked at the description 'AC/DC 600Amp tester'. Try this one, it is a bit more expensive but looks like a better unit but is £25'ish: https://www.ebay.co.uk/itm/UNI-T-UT210E-Handheld-RMS-AC-DC-Mini-Digital-Clamp-Meter-Resistance-Capacitance/232012176542?hash=item360500dc9e:g:2J0AAOSwAPlXhvd- It has both a DC 20amp range and more sensitive DC 2amp range. Link to comment Share on other sites More sharing options...
Alanb Posted August 29, 2018 Share Posted August 29, 2018 An interesting item Allan. More sensitive than the one that I currently use which has a 40A lowest range. However not suitable for Rooster63's immediate problem, as it has to come from China. Alan Link to comment Share on other sites More sharing options...
plwsm2000 Posted August 29, 2018 Share Posted August 29, 2018 I just ordered one from Amazon, and although it is a few quid extra, it should arrive tomorrow. It seems a good item to carry in the van for emergency use. A few points to note however - It is only CAT III 300V so not really safe to use on 240V EHU outside of the van. 240Vac inside should be ok though. Might not be that accurate to measure solar currents. My Votronic MPPT pulses the current into the battery rather than a steady DC current. The clamp meter is supposed to be a true rms but has a low frequency limit, so the error could be quite large (but I am not complaining for something costing around £30). Apparently there is 210D and a 210E model.The "E" goes down to 2A while the "D" is 20A so not as useful IMO. The "D" does have a temperature probe though. Link to comment Share on other sites More sharing options...
rooster63 Posted August 29, 2018 Author Share Posted August 29, 2018 Have now found that when on EHU even if the Rovert charger which I use for the leisure battery charging is switched off the 240V sockets and the fridge are still on so will leave my CTEK smart charger connected so have got the minimum amount of appliances connected whilst away. Will maybe investigate what is causing the drain but not sure even if I locate it whether its worth the bother of having to remove a fuse or 2, especially if it is one under the bonnet. Link to comment Share on other sites More sharing options...
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