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Battery charging

  • 25-04-2020 10:52am
    #1
    Registered Users, Registered Users 2 Posts: 114 ✭✭


    Hi guys
    As I am currently cocooned, haven't driven the car now in over a month. I am worried about the battery. Neighbours around me in same boat looking into engines with flat batteries.
    I put charger on last week and charged to full. Can anyone tell me if charging battery like this replicates normal charging by driving and how often it would necessary to do it.
    Grateful for any advice


Comments

  • Registered Users, Registered Users 2 Posts: 161 ✭✭Mr.Cool2015


    Hi guys As I am currently cocooned, haven't driven the car now in over a month. I am worried about the battery. Neighbours around me in same boat looking into engines with flat batteries. I put charger on last week and charged to full. Can anyone tell me if charging battery like this replicates normal charging by driving and how often it would necessary to do it. Grateful for any advice


    Charging your battery with a charger regularly will eventually destroy your battery. Disconnect the battery once fully charged,it won't lose its power afterwards.

    I know a guy who disconnected his car's battery and left it parked for 6 months.

    He reconnected it and it was back to normal for him, just the tyres needed replacing because of dry rot.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    I'm
    Charging your battery with a charger regularly will eventually destroy your battery. Disconnect the battery once fully charged,it won't lose its power afterwards.

    I know a guy who disconnected his car's battery and left it parked for 6 months.

    He reconnected it and it was back to normal for him, just the tyres needed replacing because of dry rot.

    Thanks for that. So, the one charge should be sufficient?
    However, not technical enough to disconnect battery as it is pretty complicated in there, not like the old days. There's also an auxiliary battery in there.
    Leaving it connected, roughly how long should charge last?


  • Registered Users, Registered Users 2 Posts: 14,907 ✭✭✭✭CJhaughey


    Charging doesn't destroy a battery.
    Leaving a Battery flat will destroy it much faster than any potential overcharge situation.
    Overcharging will eventually kill a battery but these days you can get smart chargers which can be hooked up and left with no ill effects, the only issue is that some of them won't recharge a battery which is less than 2v, if your battery is less than 2v then you may have to try and recover it with a dumb charger first before connecting a maintenance charger.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    CJhaughey wrote: »
    Charging doesn't destroy a battery.
    Leaving a Battery flat will destroy it much faster than any potential overcharge situation.
    Overcharging will eventually kill a battery but these days you can get smart chargers which can be hooked up and left with no ill effects, the only issue is that some of them won't recharge a battery which is less than 2v, if your battery is less than 2v then you may have to try and recover it with a dumb charger first before connecting a maintenance charger.

    Thanks CJ
    Hopefully, we'll get some release from this nightmare in the next couple of weeks. It's a long time since I've used the charger but, I think it cuts off when the battery is charged. I wouldn't leave it on, but, maybe in another week or so, give battery another charge if I don't get to drive.
    I seem to be surrounded by neighbours with flat batteries, somebody will make a few bob out of this


  • Registered Users, Registered Users 2 Posts: 8,800 ✭✭✭jmreire


    Thanks CJ
    Hopefully, we'll get some release from this nightmare in the next couple of weeks. It's a long time since I've used the charger but, I think it cuts off when the battery is charged. I wouldn't leave it on, but, maybe in another week or so, give battery another charge if I don't get to drive.
    I seem to be surrounded by neighbours with flat batteries, somebody will make a few bob out of this

    They will, and not only that, because it's not just as straightforward nowadays to swap out a flat battery and replaced it with a new/charged one...a lot of modern cars will show faults from having a flat / low charged battery in them, and these faults will need clearing on a diagnostics computer. But as CJ says, its possible to get a special charger that can be left charging permanently..they are automatic, and adjust themselves to the charge status of the battery. Google"CTEK Charges".


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  • Registered Users, Registered Users 2 Posts: 161 ✭✭Mr.Cool2015


    Thanks for that. So, the one charge should be sufficient? However, not technical enough to disconnect battery as it is pretty complicated in there, not like the old days. There's also an auxiliary battery in there. Leaving it connected, roughly how long should charge last?


    Not sure if one charge would be sufficient or not and how long it will last for, depends on what car you have.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    Not sure if one charge would be sufficient or not and how long it will last for, depends on what car you have.

    A Class Merc


  • Registered Users, Registered Users 2 Posts: 161 ✭✭Mr.Cool2015


    CJhaughey wrote:
    Charging doesn't destroy a battery. Leaving a Battery flat will destroy it much faster than any potential overcharge situation. Overcharging will eventually kill a battery but these days you can get smart chargers which can be hooked up and left with no ill effects, the only issue is that some of them won't recharge a battery which is less than 2v, if your battery is less than 2v then you may have to try and recover it with a dumb charger first before connecting a maintenance charger.


    What I was trying to say is that if you regularly charge a battery after it goes flat, that would eventually have a negative impact on the battery.

    Of course,if there is some power in the battery and you charge it then you shouldn't have a lot of problems.

    In case of the OP, as they're not technical enough to disconnect the battery, the smart charger you mentioned is the best option for them.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    What I was trying to say is that if you regularly charge a battery after it goes flat, that would eventually have a negative impact on the battery.

    Of course,if there is some power in the battery and you charge it then you shouldn't have a lot of problems.

    In case of the OP, as they're not technical enough to disconnect the battery, the smart charger you mentioned is the best option for them.

    Battery still had just under half charge, so it wasn't too bad. My query really was just to figure out the best way to keep it charged as much as possible without doing damage, or if I was doing damage by using charger


  • Registered Users, Registered Users 2 Posts: 161 ✭✭Mr.Cool2015


    A Class Merc


    I have a Nissan Almera, so there's a difference there but I know that Merc's don't like battery depletion. One of the lads I know had a 07 S Class with two batteries sitting for a few months while he was away, the primary battery died and the secondary battery had a bit of power left so that survived. He wasn't able to jump or charge the primary battery so he ended up replacing it, but that was before smart chargers were introduced.


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  • Registered Users, Registered Users 2 Posts: 161 ✭✭Mr.Cool2015


    Battery still had just under half charge, so it wasn't too bad. My query really was just to figure out the best way to keep it charged as much as possible without doing damage, or if I was doing damage by using charger


    Ok, that's fine then.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    If I was to go by the hand book I'd be afraid to go anywhere near the battery, but, the charger definitely fully charged it and no problems that I can see.
    I know there is an auxiliary battery somewhere but absolutely no mention of it anywhere in the handbook. I think it just runs the start/stop system which is a pain in the h*** anyhow


  • Registered Users, Registered Users 2 Posts: 8,800 ✭✭✭jmreire


    A Class Merc


    For sure Merc's will show fault codes for any kind of electrical fault,,,,battery flat, low output, charging rate etc.


  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    Battery still had just under half charge, so it wasn't too bad. My query really was just to figure out the best way to keep it charged as much as possible without doing damage, or if I was doing damage by using charger

    A smart charger like the Ultimate Speed ULGD 3.8 A1 (max, 3.8A) will charge up and maintain your battery with no ill effects even if you forget to disconnect as it (or any of these smart chargers) will vary its trickle charge between 0.1A & 0.8A once the battery is fully charged, the important thing to remember is not to let the battery fully discharge as relatively few of these will kill the battery very quickly.
    If the battery voltage is < 7V then this particular charger will not charge the battery but will show a error code.

    The chart below gives a indication of the battery SOC (state of charge), ideally these voltages should be taken with the battery disconnected but it still gives a reasonable indication of SOC with the battery connected with every thing switched off.

    Volts Capacity %
    11.51 10
    11.66 20
    11.81 30
    11.96 40
    12.10 50
    12.24 60
    12.37 70
    12.50 80
    12.62 90
    12.73 100


  • Registered Users, Registered Users 2 Posts: 383 ✭✭Waterson


    Hi OP,
    Probably the simplest way to keep battery charge topped up is to run the engine for 15 mins 2-3 times a week. I'm not sure what your area is like but if you have concerns over car being lifted from driveway and you have a spare key, start the car, then lock it with spare key and have a cup of tea.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    Thanks for that
    I always thought short starting like that used more battery than was put back. However, as you say, probably the best way at the moment. Keyless start, I'll have to keep an eye out


  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    Pretty much all modern cars have some form of smart alternator charging now which IMO never results in a fully charged battery, all my older cars charged at a constant 14.2/14.3V which gave a fully charged battery, a 1 year old Polo will initially charge to ~ 14.8V but very quickly settles down at 13.3V, even in pre covid days with plenty of driving the battery was only 70/80% charged. If I only ran it these days for 15 mins a few times a week it wouldn,t achieve very much whereas the charger brings it right up to 12.7V after ~ 1.5 hrs/week. IMO, this is a far better method of keeping your battery healthy and bring the car for a 30 minute drive (if possible) every 2 weeks or so.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    [QUOTE=John.G;11329036
    and bring the car for a 30 minute drive (if possible) every 2 weeks or so.[/QUOTE]

    That's the problem when cocooning, not supposed to go anywhere and I'm a law abiding citizen. So, conflicting advice here.
    Run for 15 mins or charge? that is the question


  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    IMO, charge, with a suitable charger, can you post your charger details please.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    It is a Sealy Autocharge12 12V/12A 45-180Ah Automatic Battery Charger

    Suitable for lead-acid or low maintenance batteries, the chargers react continuously to battery condition and deliver whatever charge rate is required. Reverse polarity protection prevents inadvertent damage to charger. LED indicators confirm the status of the charger and an analogue ammeter gives an accurate indication of charge rate. These electronic chargers can be connected to a battery for an indefinite period - the intelligent circuitry constantly monitoring the voltage and maintaining the charge level at optimum


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  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    That looks pretty smart to me, it has a ammeter so when the LEDs indicate full charge the amps should be ~ 0.5/1.5 which should also indicate full charge, depending on the parasitic battery load it might read a bit higher than this but one way or the other if you switch it off when the LEDs indicate so, you should be fine.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    Thanks for that John.G very helpful, though I have no idea what a "parasitic battery load" is

    I wouldn't want to be using the charger too often but, it seemed to me that a boost now and again should do no harm. However, when you read the manual it makes it sound so complicated because of internal computer etc. It's a bit worrying when this stuff is well outside my expertise.


  • Registered Users, Registered Users 2 Posts: 383 ✭✭Waterson


    Thanks for that
    I always thought short starting like that used more battery than was put back. However, as you say, probably the best way at the moment. Keyless start, I'll have to keep an eye out

    I can see why you may think that, however modern automotive batteries are designed to be discharged and recharged continuously, so even though starting it after an extended period of time will draw down a large amount of current, the battery is designed to cope with the counter electromotive load put on it by a cold, stationary engine, (this is the CCA or cold-cranking amperage you will see printed on the battery label).
    A trickle charger will also keep a battery topped up, just more hassle to set it up. They works in fundamentally the same way as the alternator on your engine, pumping current into the discharged battery cells to create potential.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    Many thanks for all the advice here lads

    A lot of conflicting advise though. Probably best to take a sneaky drive now and again, but I don't like to do that as I feel "rules is rules" and better for all to obey them.


  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    That parasitic battery load is the electrical load required by the car electronics while the car is off, it can vary from 0.05A to 0.1A and probably higher in some cars so the battery will slowly loose its charge over time, most car batteries should last 10 days or longer and still retain half charge, I think your posts indicated that you still had half charge after ~ 2/3 weeks? which would seem OK. Suggest that after you charge it fully that you then take a reading after 1 week and see what the state of charge is and you will quickly see how often to recharge it but shouldn't allow it to fall below 50/60% IMO before recharging.


  • Registered Users, Registered Users 2 Posts: 114 ✭✭Gobethewall


    Excellent piece of info
    Thanks for that John.G


  • Posts: 0 [Deleted User]


    All this faffing about looking for chargers and jump-leads...just go for a good drive "going to the shop"


  • Registered Users, Registered Users 2 Posts: 1,355 ✭✭✭Belfast




    Automotive Battery Chargers - Jay Leno's Garage
    the above video gives good advice on cars not being driven and charging.

    I bought one a few years ago as I drive very little and had problem with batteries going flat.
    I found it worked well for me.

    CTEK MXS 5.0 Fully Automatic Battery Charger (Charges, Maintains and Reconditions Car and Motorcycle Batteries) 12V, 5 Amp - UK Plug
    https://www.amazon.co.uk/CTEK-MXS-5-0-Reconditions-Motorcycle/dp/B00FC42HAA/ref=sr_1_5?dchild=1&keywords=ctek+battery+charger&qid=1588384161&sr=8-5


  • Registered Users, Registered Users 2 Posts: 14,907 ✭✭✭✭CJhaughey


    salonfire wrote: »
    All this faffing about looking for chargers and jump-leads...just go for a good drive "going to the shop"
    You obviously have little understanding of modern charging systems.
    A good smart charger will put a battery back into almost new condition and keep it there almost indefinitely, easily until the restrictions are eased somewhat.
    I have my car hooked up to a Procharger Xl right now its only a 4 Amp unit and has taken most of the day to get up to nearly 100% but once there it will maintain it until I change over to one of the other vehicles that need Battery maintenance.
    Its not faffing about its actually preventative maintenance and the cost of a very good smart charger is a lot less than a battery costs to buy.


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  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    Agree with above, I too smart charge during these cocooning days. I've also noticed that on two, one year old VWs, that the alternator only supplies a steady 13.3V which IMO will never get a battery up to 100% SOC, so one could drive them all day and the battery will never be fully charged. Formerly, all VWs and quite a few other makes that I have monitored charged at 14.2/14.4V which led to very long battery lives, in my own case, 10/12 years. There appears to be a monitor of some sort now attached to the battery negative terminal (2019 Polo). On start up, the battery goes up to ~ 14.8V for a few seconds then settles down to 13.3V. Has anyone any views on this or would care to monitor their voltage on any make of relatively new car.


  • Registered Users, Registered Users 2 Posts: 383 ✭✭Waterson


    The smart charging systems that you are describing have been designed to conserve energy by varying the electrical output from the alternator. The strength of the field voltage to excite the windings in the alternator is varied depending on the load requirements by driver. For example, you may notice on your 2 one year old Volkswagens that you will have 13.3 V with engine idling and no consumers switched on. However, say your are driving on a cold winter night with all lights on, rear demister, heater blower on full, that the charging voltage will be more like 14-14.5 V.
    You are correct in saying that the current output from the battery is monitored at the negative pole of the battery and this feeds into the charging loop decisions made by the ECU.
    The chemical composition and design of batteries, conservation of energy, reducing engine load and fuel consumption targets are all reasons that alternators are not simply outputting 14 V at all times.


  • Registered Users, Registered Users 2 Posts: 3,623 ✭✭✭John.G


    Yes, the good old days of long lived batteries (> 8 years in my book) are probably over for good in the interests of the above.
    I can certainly state that this 2019 Polo does not increase the charging voltage with increasing electrical load, in fact when fully loaded (no A/C in this car) and driving at ~ 2.5 to 3k RPM, the voltage stays very steady at 13.3V, in fact it drops very very slightly with the increased load.
    I will be interested to see if it increses/decreases with battery age or in very cold weather.


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