Mark Posted January 7 Share Posted January 7 (edited) Hi all Been looking at Solar Battery maintainers for my van as it sits for long periods unused, and needed to re-charge the battery a couple of times lately. Could be useful for the gt6 also. Looking on ebay they are pretty cheap. What sort of wattage output should I be looking at? AA version offers 4.8 watts output, but lot cheaper versions range from 10 to 100 watts output. Also would I need separate charge controller or is the output at a lower enough level not to cook the battery if connected long term? Thanks. Edited January 7 by Mark Link to comment Share on other sites More sharing options...
JohnD Posted January 7 Share Posted January 7 Mark, My TRansit came fitted with an electrical hook-up point on the outside, and a three-pin socket inside, so I installed a CTEK MX5 battery charger in the van and connect it to a power point in the garage. John Link to comment Share on other sites More sharing options...
DeTRacted Posted January 7 Share Posted January 7 (edited) If your battery is really discharging deeply with no load on it over a few weeks, it is probably on the way out. If you're starting with a battery which is fully charged when you park up, the battery maintainer should only need to provide a very low current to compensate for any self-discharge. A hundred milliamps or so will be more than enough, which translates to 1.2 watts. Any more than that and it isn't just maintaining the battery but trickle-charging it. The rated wattage of these charging devices is just what they can provide - not necessarily what they will provide. That depends on the state of charge of the battery, so a (say) 12 watt charger can provide a maximum of 1 Amp [I=P/V] which will take days to charge the battery if it is low, but once the battery reaches full charge the current should tail off to a maintenance level only. You shouldn't need a separate controller if you buy one made for 12v batteries. You will probably get what you pay for, so a very cheap device with a high power may not be a good idea if it ends up damaging the battery. Be aware it is not a good idea to leave a battery on charge for a long time if the current is above the very low level needed for maintenance. That can cause loss of electrolyte through electrolysis. Edited January 7 by DeTRacted Link to comment Share on other sites More sharing options...
zetecspit Posted January 7 Share Posted January 7 I have looked (very briefly) at Solar chargers as I keep a couple of cars in lockups. I think a lot of the cheap "chargers" are just a solar panel and uncontrolled, so I would be wary of them. The AA one may well be OK, as it is low enogh charge rate. I concluded I will eventually get a panel and a seperate controller. With the panel attached to the roof of said garages. I reckon I can also add an LED or two into the system allowing me to light the garage up using the car battery as the power source, which would be very handy as lockups get dark. Link to comment Share on other sites More sharing options...
Mark Posted January 7 Author Share Posted January 7 Thanks for all the replies and the comprehensive explanation by Detracted. Think I'll go for the AA offering as it comes with OBD2 connectivity, as I cant use the van 12 volt lighter socket, as it's not live until the ignition is switched on. The Battery a Yusa 5000 80AH battery started playing up after about a year, discharging in cold weather. Returned it to the suppliers who tested it with a hand held device that gave a print out stating the battery was fine. Replace the alternator to rule it out, next period of cold weather, battery goes flat, took it back again, tested, nothing wrong with it apparently. That was probably 3 years ago. Ok in warm weather dies in the winter. Possibly just down to very little use, which has probably killed the battery, or I was sold a dud. Got an old Halfords battery, that is at least 10 years old, again only gets occassional use but just soldiers on. Admittedly the diesil van uses a lot more cranking effort than a straight six. Link to comment Share on other sites More sharing options...
JohnD Posted January 7 Share Posted January 7 If - IF - the battery is good, then a gradual discharge could mean that there is a drain on the battery when the van is not in use. It'll be a small current, less then 10A, so a cheap multimeter would be able to measure it. Disconnect the main terminal, set the multimeter to Amps and place it between the battery and connector. John Link to comment Share on other sites More sharing options...
Mark Posted January 7 Author Share Posted January 7 Hi John Good point, I'll give it a go. Like I said, battery struggles when it's cold, but possibly there is a drain, and in the warmer weather the battery is able to cope. A year or so ago I disconcted a dummy Alarm red flashing light on the dash, came with the van. This was after the van was broken into and my new ultra low jack was stolen, so never fooled the thief. It had occurred to me then that maybe the flashing light was draining the battery, but thought it unlikely. I do have a battery disconnect on the van but then I can't lock it. Link to comment Share on other sites More sharing options...
zetecspit Posted January 7 Share Posted January 7 I had an irritating drain on my spitfire. After a bit of faffing, it turned out to be a USB charger left in the fag lighter (permanent live) Pulled it out and the current draw fell to zero, which was a great relief. The draw was only 0.1A, but that is 2.4Ah/day which soon adds up. Link to comment Share on other sites More sharing options...
Mark Posted January 12 Author Share Posted January 12 Looks like John was right. Everything switched off, I have a battery disconect on the earth terminal, so turned the knob to disconnect the earth. Connected a test lamp to the battery earth post and the earth lead and the test lamp illuminates, but strange thing is that it pulses? I set my multimeter to amps to try and measure the drain through the earth, but it just reads 000, so maybe the multimeter is faulty, or Iam doing something wrong. My first thought was the interior lights, as there is a timer that switches the lights off if the door is left open. There is the option of auto or off so I switched the interior lights to the off position, but there is still a drain, test light stay on. Pulled the fuses from the interior light circuit, but the test lamp still stays illuminated. Trying to think what could be causing there test light to pulse? Here's a link to a short clip I uploaded to YouTube. https://youtu.be/lG2bE_HTUyk?si=HVPsuD0kWTXlqEI_ Link to comment Share on other sites More sharing options...
JohnD Posted January 12 Share Posted January 12 (edited) What's the frequency of the pulse? The part that does this on Triumphs (and many other classics) is the temperature, and I think the fuel gauges. They are supplied though the mis-titled "voltage stabiliser" which produces an average 10V by chopping the supply on and off, thus: 12V (or whatever battery volts are at that time) - 0V - 12V - 0V - etc. What is your van? Does it have gauges that have such a supply? If you can identify it, pull the fuse that supplies the gauges. Ah! I've seen your video! That's about the rate that a "stabiliser" oscillates at! But, you're using a test screwdriver, rather than a test lamp. The bulb in those isn't an incandescent but a neon tube, and it will respond to a VERY small current, so small that you can test a mains circuit by putting the end onto a live wire and your finger on the top button. JUST enough current flows into your finger to light the bulb, but not enough to harm you, or even feel it! This current into you, that the screwdriver shows, is too small to be measured by a digital multimeter. It may be that connecting across the disconnect with your screwdriver and another rod energises the loom, and your finger on the top of the screwdriver is sensing this. Certainly the circuit you are using does NOT check the current across the disconnect. Make up a test circuit with a incandescent bulb and put that across the disconnect. Good luck! John PS I feel the need for the University's Dept. of Electrical Engineering, but would an LED work better than even a low wattage incandescent? I think so! But remember that LEDs have polarity - you must connect it the right way around! J. Edited January 12 by JohnD Link to comment Share on other sites More sharing options...
DeTRacted Posted January 13 Share Posted January 13 (edited) No John- that looks like a 12v test screwdriver which has a normal festoon bulb. You can't light a neon mains-test screwdriver from car battery voltage. It looks to me as though it is connected across the disconnect. What that test does show is that the current drain is substantial, maybe in the order of 100 mA but you can't set too much store on that because the series resistance of the lamp is limiting the voltage to the load, which is maybe why whatever it is pulses because it isn't getting full supply voltage. It could be trying to turn on but failing because the voltage is too low, so keeps having another go. You can only make a meaningful measurement like that with an ammeter - preferably a moving-coil one. Pulling fuses until it stops is a good way forward to isolate the problem area but not very much help if there are only a couple of fuses. What is the vehicle? There may be a wiring diagram on-line which could give a clue. (Multimeters sometimes require the probes to be moved to a dedicated socket for current measurement and there is often a meter fuse to prevent catastrophe if connected wrongly on amps. If that has happened the meter won't work on that range until the fuse is replaced. A neon lamp typically takes 80-90 volts to 'strike' and the current in those mains test screwdrivers is limited by a large value series resistor. If that resistor wasn't there the glow would turn in to an arc and amps could flow for a short time, until you let go or the neon melted ) Edited January 13 by DeTRacted 2 Link to comment Share on other sites More sharing options...
Mark Posted January 13 Author Share Posted January 13 Thanks for the replies and advice. Yes, the screwdriver is an a ancient 12 volt tester. The van is a 2005 citreon relay 2litre Hdi. Repeated the test a couple of times, bulb light pulsed again then went out, disconnected the tester then touched the earth lead again, light lit up and I could hear a clicking noise, it was the Speedo and revcounter pointers jumping off their stops and twitching, this with the Ignition off. Repeated the test briefly no clicking, just the test light pulsing. I will start buy pulling the fuses, there are probably 20 or so, plus relays, but will look for an instrument cluster fuse first. Checked the fuses in my multimeter the 10amp is intact but the 600mA has blown. Probably buy a cheapo multimeter for now to try and get an idea of the current being drawn. Link to comment Share on other sites More sharing options...
DeTRacted Posted January 13 Share Posted January 13 Aaah. That van will have all sorts of electronics which are permanently connected, - any of which can be faulty. One possibility - does the van have a built-in alarm? If so, those alarm modules often have internal rechargeable cells so the alarm doesn't stop if some scrote manages to disconnect the vehicle battery. What can happen with some types is those rechargeable cells degrade and start to pull a continuous current from the battery either directly or by corroding the circuit board. 1 Link to comment Share on other sites More sharing options...
Mark Posted January 13 Author Share Posted January 13 Thanks for the thoughts, but this van dosen't have an alarm. Possibly lack of use, corrosion somewhere in the loom components, relays etc. Is the cause. Seem to recall the instrument panel is one big circuit board. Been blaming the slow turn over on a dodgy battery for the past few years, so at least I know there is a fault, and if I had replaced the battery would be in the same position in a couple of weeks. Interestd to find the fault now and hopefuly fix it. Trouble is it's stopping getting on wiyh he spit restoration. Link to comment Share on other sites More sharing options...
JohnD Posted January 13 Share Posted January 13 Thank you for the correction, Prof. DTR! I'm sure that Mark will find your tutorials more useful! And yes, a Citroën! I had a C5, which when it was good was very, very good, but when it as not (handbrake locks on, multiple dashboard warning lights, etc.) it was HORRID! It had to go and it did. John Link to comment Share on other sites More sharing options...
spitfire6 Posted January 26 Share Posted January 26 On 1/7/2024 at 9:53 AM, Mark said: Hi all Been looking at Solar Battery maintainers for my van as it sits for long periods unused, and needed to re-charge the battery a couple of times lately. Could be useful for the gt6 also. Looking on ebay they are pretty cheap. What sort of wattage output should I be looking at? AA version offers 4.8 watts output, but lot cheaper versions range from 10 to 100 watts output. Also would I need separate charge controller or is the output at a lower enough level not to cook the battery if connected long term? Thanks. Hi, A 5-Watt solar panel is unlikely to overcharge a 12v Battery that is more than 50Ah. A low Vf diode would be required to stop the solar panel from discharging the battery. A 100+ Watt panel would need a charge controller. An expensive MPPT controller would make it much more efficient. Cheers, Iain. Link to comment Share on other sites More sharing options...
Mark Posted January 28 Author Share Posted January 28 Thanks for replies. Cause of the drain on the battery turned out to be the factory radio. Pulled all the fuses in turn but still had the test light pulsing. Started dismantling the dash to get to parts of the loom and to the back of numerous switches, and while at it replaced 5 bulbs that iluminate the heater controls, so not a total waste of time. Then noticed the test light had gone out, thought if may have been a dud bulb causing a short. Put everything back, test light started pulsing. Last thing I connected was the stereo. Pulled the 10amp fuse from the back of the unit test lamp went out. Although switched off it must have a constant live for the memory, don't no why it never went out when pulling the audio fuse from the fuse box. So something in the radio is faulty. Anyway after leaving the battery connected for a few cold days, battery span the van over with no problems. I was convinced I had a dud battery for the past couple of years. It was only thanks to John suggesting a possible parasitic drain that got me looking, I really didn't expect it to be. Back to the Spitfire restoration! 1 Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted January 28 Share Posted January 28 2 hours ago, Mark said: Thanks for replies. Cause of the drain on the battery turned out to be the factory radio. Pulled all the fuses in turn but still had the test light pulsing. Started dismantling the dash to get to parts of the loom and to the back of numerous switches, and while at it replaced 5 bulbs that iluminate the heater controls, so not a total waste of time. Then noticed the test light had gone out, thought if may have been a dud bulb causing a short. Put everything back, test light started pulsing. Last thing I connected was the stereo. Pulled the 10amp fuse from the back of the unit test lamp went out. Although switched off it must have a constant live for the memory, don't no why it never went out when pulling the audio fuse from the fuse box. So something in the radio is faulty. Anyway after leaving the battery connected for a few cold days, battery span the van over with no problems. I was convinced I had a dud battery for the past couple of years. It was only thanks to John suggesting a possible parasitic drain that got me looking, I really didn't expect it to be. Back to the Spitfire restoration! Success! Link to comment Share on other sites More sharing options...
Nick Jones Posted January 29 Share Posted January 29 Nice find! Link to comment Share on other sites More sharing options...
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