Fit an isolation switch for the battery then, if good, it will keep for months.
Maintaining little used car batteries
- Thread starter Harry Bloomfield
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I think your right.
Yes but then you often lose radio coding. With the caravan if the battery is disconnected and reconnected than the radio auto turns on in demo mode, and with wife's car the engine management will need telling what size battery has been fitted and will send all sorts of messages to her mobile phone, with modern car not really an option.
My father-in-law was one of the few people I know who used his garage for a car, it had bonnet tucked under work bench at end of garage, and block on floor so he would stop at exactly right place so door could close, there was things along the side of garage except where the drivers door was, where there was a large lump of sponge stuck to wall so he would not damage car door, he did not use car for a time, and it seems it had electric hand brake, there was it seemed a hole in the floor some where so you could release the brake, but could not reach the hole, and also could not lift bonnet, ended up jacking up rear axle with trolley jack and using my car as anchor using ratchet straps to drag car out enough to open bonnet.
I would assume wife's car would also be a problem, on turning off, the gear selector retracts so you could not get it out of Park, or release electric hand brake, this it seems is progress?
I have just been doing a few experiments, with one of the Lidl smart chargers, the one I usually keep my car's battery charged with. Its the earlier one, which just has LED indicators, 3.8amp, a button to select the mode, red charging and green for charged. It's clipped to a roof beam and its battery clips connect to a long extension, and at the end is a ciggy lighter plug - idea is to make it quick to plug into the car and because it drapes over the steering wheel, no chance of driving off with it plugged in.
It's a brand new Varta E44 77aH battery, last week. With the * mode selected, for maximum charge - It seems the charger brings the battery up to a full charge, 14.?v. Once full, the green LED lights and the charger drops back to a maintenance charging mode - 13.05V, delivering 50/60mA. A little over 20mA is consumed by my car's electronics whilst parked, so 30/40mA going into the battery. As it is not a direct connection to the battery, there will be a tiny amount of volts drop.
Turning everything on, in the car, does not seem to trigger the green LED to go off and the charger to go back to high rate charging. The only way is to press the button to stop it, then cycle through the modes again.
I am reasonably happy to just leave the car connected permanently to the charger, whilst parked in the garage, at such a low voltage and low current.
It's a brand new Varta E44 77aH battery, last week. With the * mode selected, for maximum charge - It seems the charger brings the battery up to a full charge, 14.?v. Once full, the green LED lights and the charger drops back to a maintenance charging mode - 13.05V, delivering 50/60mA. A little over 20mA is consumed by my car's electronics whilst parked, so 30/40mA going into the battery. As it is not a direct connection to the battery, there will be a tiny amount of volts drop.
Turning everything on, in the car, does not seem to trigger the green LED to go off and the charger to go back to high rate charging. The only way is to press the button to stop it, then cycle through the modes again.
I am reasonably happy to just leave the car connected permanently to the charger, whilst parked in the garage, at such a low voltage and low current.
I have a couple of big 12 batteries as stand by for my ham radio system, they are permanently on charge but at 13.2 volts which is officially the fully charged voltage for lead acid batteries (6 x 2.2v). I bought them secondhand at least 10 years ago, could be longer and they are still doing their job.
Peter
Peter
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Car, battery and charger are outside in my detached garage, so not easy to keep a close eye on proceedings, but...
When last checked Wednesday lunch, it was showing 13.05v charging at 55mA (20mA maintaining the cars electronics, 35mA charge into the battery). I checked it again yesterday lunch and it was showing 14.03v which is a little higher than I would like, for a battery kept always on charge.
Pushing the button on the charger, so it was no longer charging, but on - the charger discharges 5mA from the battery. This will be the voltage sensing system in the charger, preventing reverse polarity and making sure the battery is properly connected before initiating its charging process.
I also have (yet another) charger, which is just a dumb charger - it senses the voltage on its terminals and refuses to charge unless the polarity is correct, when correct it outputs up to 8amps, but limited to 14.4v maximum. When unpowered, its polarity sensing circuit discharges the battery at the rate of 17mA or 0.4amp/hour per day. Total discharge from battery 17mA + 20mA = 37mA or 0.900amp/hour per day, 77amp/hour battery, so should be not too unhappy without any charge, for at least 40 days at a time. However......
I am thinking to put this last charger on a time clock, so it comes on once per day for 10 or 15 minutes. It has to be better for the battery, than my present regime of bring the battery up to a full charge every few weeks. If there is a power interruption, it will carry on as normal once power is back on.
The problem with using a smart charger is that a button always has to be pressed after powering it up, to start the charge. If there is a mains interruption, I would have to remember to go out and press the button.
Comments and suggestions welcome.
I have this car battery to care for, the caravan's 120amp/hour - I have its 12v SMPSU on permanently, just keeping it's alarm system topped up and connect the 120 main battery for a top up, once per month. Then I have a standby 72amp/hour car battery which I replaced 5 years ago, but still has some useful life in it.
Under the bench I have around 6 12v new ex-telecomms gel cells. I keep them for the same purpose as you, amateur radio (M1BYT). I give those 7 batteries a boost when I remember.
When last checked Wednesday lunch, it was showing 13.05v charging at 55mA (20mA maintaining the cars electronics, 35mA charge into the battery). I checked it again yesterday lunch and it was showing 14.03v which is a little higher than I would like, for a battery kept always on charge.
Pushing the button on the charger, so it was no longer charging, but on - the charger discharges 5mA from the battery. This will be the voltage sensing system in the charger, preventing reverse polarity and making sure the battery is properly connected before initiating its charging process.
I also have (yet another) charger, which is just a dumb charger - it senses the voltage on its terminals and refuses to charge unless the polarity is correct, when correct it outputs up to 8amps, but limited to 14.4v maximum. When unpowered, its polarity sensing circuit discharges the battery at the rate of 17mA or 0.4amp/hour per day. Total discharge from battery 17mA + 20mA = 37mA or 0.900amp/hour per day, 77amp/hour battery, so should be not too unhappy without any charge, for at least 40 days at a time. However......
I am thinking to put this last charger on a time clock, so it comes on once per day for 10 or 15 minutes. It has to be better for the battery, than my present regime of bring the battery up to a full charge every few weeks. If there is a power interruption, it will carry on as normal once power is back on.
The problem with using a smart charger is that a button always has to be pressed after powering it up, to start the charge. If there is a mains interruption, I would have to remember to go out and press the button.
Comments and suggestions welcome.
I have this car battery to care for, the caravan's 120amp/hour - I have its 12v SMPSU on permanently, just keeping it's alarm system topped up and connect the 120 main battery for a top up, once per month. Then I have a standby 72amp/hour car battery which I replaced 5 years ago, but still has some useful life in it.
Under the bench I have around 6 12v new ex-telecomms gel cells. I keep them for the same purpose as you, amateur radio (M1BYT). I give those 7 batteries a boost when I remember.
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My early Lidi charger pre the voltage display failed, I think it was my fault for using two chargers together, had a mA charger to get the Lidi one to trigger, however it was before I was using a energy meter so no graphs for that one.
I do see your point in 14.4 volt being a bit on high side, and to switch down/off it needs that 14.4 volt. Never tried two diodes reverse direction to each other, but they would drop the volts 0.6 volt but would mean it would not restart charging until 12.2 volt which I think is too low.
It seems early one you have is two stages, new 5 amp version like old 3.8 amp with voltage display has 4 stages would suggest you get the new version.
I do see your point in 14.4 volt being a bit on high side, and to switch down/off it needs that 14.4 volt. Never tried two diodes reverse direction to each other, but they would drop the volts 0.6 volt but would mean it would not restart charging until 12.2 volt which I think is too low.
It seems early one you have is two stages, new 5 amp version like old 3.8 amp with voltage display has 4 stages would suggest you get the new version.
I have one of those too, I put it on my 120amp/hour battery not 10 minutes ago, to bring that one up to a full charge in the caravan. We are due away in a couple of weeks, so I thought I would give it a boost in readiness
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I think there is an intermediate battery size that has a problem with the newer Lidi chargers, up to 20 Ah on motorcycle option it will turn off, and with a 75 Ah at 0.1 amp it will not hold a battery volts up anyway, it does depend on how good the battery is and also any discharge, but it can reach the point where it seems to just hang there, it will not raise the voltage enough to switch off or down, but is over the 13.8 volt we have considered as charging/maintaining voltage for a 12 volt lead acid for years, however we are looking at either 0.1 amp or 0.8 amp, in both cases it is a very low charge rate, and I can't see it really damaging a battery, it is more likely to be converting the last bits of hard sulphur back into acid. And at around £14 for the Lidi charger it is not worth building one just use the ready built unit.
The problem as I see it is the reverse, having fitted an energy meter, I have realised how long it takes to fully recharge a battery, up to 95% quite fast but it slows down with last 5% and if not fully recharged a little more each time ends up staying as sulphur so slowly the capacity reduces, with flooded there is no problem leaving on charge, with absorbed glass mat/valve regulated lead acid may be a slight problem, but so slight not worth worrying about.
The problem as I see it is the reverse, having fitted an energy meter, I have realised how long it takes to fully recharge a battery, up to 95% quite fast but it slows down with last 5% and if not fully recharged a little more each time ends up staying as sulphur so slowly the capacity reduces, with flooded there is no problem leaving on charge, with absorbed glass mat/valve regulated lead acid may be a slight problem, but so slight not worth worrying about.
I have it set up now on the 8 amp fixed voltage dumb charger, since yesterday morning. Charger powered from a time clock which comes on for 15 minutes, once per day. Battery at rest voltage is 12.93v. Nearing the end of the 15 minutes during which the 8 amp charger comes on, it brings the voltage up to 14.43v.
That charge regime will be not much different than if the car were started and given a daily run out, but without the heavy current discharge of starting the car.
My later model Lidl charger (with voltage display), is still charging my caravan's 120amp/hour battery. It wasn't discharged to begin with, it gets a monthly boost without fail, on the caravans 13.8v SMPSU and between times is isolated.
I spent a bit of time, toying with the idea of isolating the car's battery from the car, when the car wasn't in use - as a way to avoid the constant 20mA discharge of the car's electronic systems. Maybe and isolator switch? There wouldn't be a problem of typing in radio codes, it uses other methods of theft protection. I decided the hassle of lifting the bonnet to isolate every time, would make it impractical, versus just plugging a charging system into my lighter socket.
That charge regime will be not much different than if the car were started and given a daily run out, but without the heavy current discharge of starting the car.
My later model Lidl charger (with voltage display), is still charging my caravan's 120amp/hour battery. It wasn't discharged to begin with, it gets a monthly boost without fail, on the caravans 13.8v SMPSU and between times is isolated.
I spent a bit of time, toying with the idea of isolating the car's battery from the car, when the car wasn't in use - as a way to avoid the constant 20mA discharge of the car's electronic systems. Maybe and isolator switch? There wouldn't be a problem of typing in radio codes, it uses other methods of theft protection. I decided the hassle of lifting the bonnet to isolate every time, would make it impractical, versus just plugging a charging system into my lighter socket.
I have a remote control roller door and to prevent the door trying to close onto an obstruction, I installed an IR beam across the door at tow ball height inhibiting the door close. I then got the bright idea of running an LED off the beam unit relay, wired to a point I could see ahead of the car as I drive in nose first. LED lit, when there is no obstruction in the way of the door closing. As I drive in, the LED gives a brief flash as it 'sees' the gap between bumper and ball, then stays on once clear of the door. I fitted a wired up, down and stop buttons to the door controller, so I could operate the door inside the garage.
After a few years use, the push buttons on the 2x remotes were starting to become a bit 'iffy', so I bought a couple of centre return toggle switches to wire into the remotes and made fixing brackets for them. One is fixed by the back door and the other one is fixed in the car. Much better than searching round for misplaced remote controls
I can just push the toggle as I get in the drive, to open the roller door. One day, I might get around to electrifying and remote controlling the drive gates - or maybe not. The faff of getting the car in and out is a great encouragement to just walk or catch the bus for a lightweight shop.
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My father-in-laws electric garage door was always a problem, first they failed to fit a manual override, and only way in the garage was through that door, and consumer unit in the garage, they returned and modified with a keyed pull out, it pulled out a pin so you could lift the door, then it was use of remote controls, it was in a pocket next to front door, he would push it as he went in and you could hear door closing, but one stone under door and it would reopen, he was next door but one to us, number of time we knocked on door to say garage door is open I lost count.
But he would not go out to close it, just pressed button again and always seemed to close, trapping a cat once.
It did worry me this just press the button, be it a cat or child he never checked, here never close the garage door it is bent and does not easy close, but you can't see it from road, and nothing of any value kept in it. And door too narrow to get car in, trailer is parked in it only. Why the previous owners of the house built it don't know, I would guess motor bike.
I have never closed the gates since moving in, don't know if I could, but as far as electric goes the rules mean rather expensive to fit today, after the Manchester child death councils are very quick to want to see all the paperwork to show they pass all the safety requirements, and in the main that means they are not secure, so why fit them.
As to batteries I had hoped the mobility scooter battery a 35 Ah AGM would recover, but seems it will not, so £86 for a pair, other one had clearly failed. Plus £8 delivery, I had thought of picking them up, but fuel would cost more than £8. I think one battery had a shorted cell, and the rest of the cells were killed as a result of over charging because one cell shorted, can't see any way to protect from that other than a time limit on charger. Big problem is there is no option to charge off the scooter, so whole scooter has to be taken into the house to charge.
But he would not go out to close it, just pressed button again and always seemed to close, trapping a cat once.
It did worry me this just press the button, be it a cat or child he never checked, here never close the garage door it is bent and does not easy close, but you can't see it from road, and nothing of any value kept in it. And door too narrow to get car in, trailer is parked in it only. Why the previous owners of the house built it don't know, I would guess motor bike.
I have never closed the gates since moving in, don't know if I could, but as far as electric goes the rules mean rather expensive to fit today, after the Manchester child death councils are very quick to want to see all the paperwork to show they pass all the safety requirements, and in the main that means they are not secure, so why fit them.
As to batteries I had hoped the mobility scooter battery a 35 Ah AGM would recover, but seems it will not, so £86 for a pair, other one had clearly failed. Plus £8 delivery, I had thought of picking them up, but fuel would cost more than £8. I think one battery had a shorted cell, and the rest of the cells were killed as a result of over charging because one cell shorted, can't see any way to protect from that other than a time limit on charger. Big problem is there is no option to charge off the scooter, so whole scooter has to be taken into the house to charge.
I have the roller door, a small code access side door, plus a wide door for access to my add on workshop. I have never had animals trapped in there, well apart from one of the dogs. I spend odd bits of time in my workshop fixing things, which I enter via the small code door. The dog tends to follow me and likes to hide out the way and doze, under the back of car, between car and roller door. I've long since lost count of the number of times I have finished in the workshop, come out, turned the lights out and slammed the small door shut with her inside. I have developed the habit of knocking on the door now and listening for movement, before slamming it shut. She is of a size (border collie) that she cannot turn around from where she lies, so she has taught herself to reverse out from under the car and all the way down the side of the car to the back door, then she appears blinking in the light.
My car has built in monitoring, but thanks.
I have had the Lidl charger, the model with the voltmeter, in the caravan, charging its 120amp/hour battery for the past four days. It was still showing 'charging', late yesterday evening, but showed fully charged this morning so I have taken it off. I was beginning to wonder if it was beginning to fail, because of the amount of time it was taking to come to a full charge. This is the battery I connect once per month for a couple of days, to the always on 13.8v SMPSU in the caravan, as a maintenance measure.
The battery is around 8 or 9 years old, so I wouldn't be surprised if it failed now, I have certainly had my moneys worth out of it. It is sort of reassuring, the longer within reason it takes to recharge a battery.
The battery is around 8 or 9 years old, so I wouldn't be surprised if it failed now, I have certainly had my moneys worth out of it. It is sort of reassuring, the longer within reason it takes to recharge a battery.
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