One of the best known UK battery "conditioners" made by Airflow is here www.calamander.co.uk/batteryconditioners/airflow.h...m I don't think you even have to disconnect the car leads.
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That looks exactly like what I've got and was describing above, with a different logo. You can leave it hooked up all the time, no battery disconnection needed, that's the whole point of it.
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Yes, Victorbox/Growler. I use an Airflow to keep the Minor battery topped up. Only charges when necessary and works a treat - fit and forget until you use the car. I've also used it to boost the battery on newer cars when they've been out or service for a week or two, and had no problems.
Regards
John S
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Now that I've been provided with a car for business use, my own Rover spends its weeks in the garage and only comes out at weekends. Sometimes it's in the garage for several weeks at a time.
So, I bought a Draper Battery Master from Halfords. £20. You plug it in, connect to the battery terminals, lock your car and leave it. Keeps the battery topped up all the time with a trickle charge. It has a max output of only 300mA and is designed to be left connected. After being connected for 2 weeks once, I checked its output and it was supplying just 10mA and the battery was definately fully charged jugding by the ease with which the engine started.
Works for me and easily available.
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A trickle charger will be fine with the battery still connected to the vehicle.
--
groups.msn.com/honestjohn/problems.msnw?Page=1 - Pictures say a thousand words.....
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I use the Optimate III on my Yamaha R6 bike. It is a battery conditioner rather than a charger, ie it monitors the battery conditon and only trickle charges when necessary. You basically just plug it and leave it, safe in the knowledge that next time you want to go out and play on your bike or your car in this case, it will be charged up and ready to roll. It does everything necessary to keep your battery in tip top condition automatically.
Have a look at this website for a good product overview of the Optimate III.
www.cusworths.co.uk/pages/road/parts/battery_charg...m
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Does anyone know if the solar panel type chargers are any good?
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Previous discussion on the subject:-
www.honestjohn.co.uk/forum/post/index.htm?t=14038&...f
Probably also some more threads, if you use the "search forum" just under where you log in/out.
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My Vectra TDi has a AC Delco sealed for life battery which is as fitted from new although this was replaced recently.
In the cars handbook it states that the battery is to be disconnected before charging.
The Airflow and Accumate suggest otherwise. So what are the true facts behind this conflicting advice.
What do the garages do for example and is there a possibilty of damage to the car ECU or other electronics?.
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On a related issue, I keep an old (but still serviceable) battery from SWMBO's Renault 5 (long gone to the scrapyard in the sky) in the garage as both an emergency spare and also as a useful source of 12V power when testing automotive bits & bobs.
I keep it regularly trickle charged of course, but there used to be a school of thought that recommended a perodic slow discharge (through a light load such as a headlamp bulb or similar) followed by a thorough recharging.
Anybody any thoughts on this practice (say once every 2 months or so)?
Regards
RM
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Alvin
The recommendation to disconnect is for two main reasons:
1/ overvoltage from the charger causing gassing of the battery cells (particularly dangerous in the case of a sealed battery).
2/ over voltage from the charger causing damage to vehicle electronics.
Most battery chargers or so called trickle chargers (and ALL the cheaper ones) provide a constant current to the battery which means that the voltage rises as the battery is charged. If the voltage exceeds about 13.7-13.9v (depending on temperature) the battery cells start gassing. Some of these chargers will give voltages up to 18v which can also damage vehicle electronics if they are in the live circuit.
A battery conditoner (or a three/four stage battery charger) such as the Optimate is electronically controlled and varies voltage AND current to avoid gassing the battery and also to achieve (and maintain) a charge above 80% which the conventional cheaper chargers find very hard to do.
The Airflow is different, it charges at a constant current as the cheaper chargers do, but avoids the gassing problems by switching off when the battery reaches a pre-determined voltage. But unlike the Optimate type the battery may or may not be fully charged at that point. If an Airflow is left permanently connected to the battery the battery charge will decay over time until a pre-determined low voltage will cause the charger to switch on again. This 'on-off' charging method is nothing like as sophisticated as the Optimate type (or similar types from Battery Tender and Gunsons) which can recover deeply discharged batteries, bring them to 100% charge and maintain them at that charge if left permanently connected.
The cheapest electronically controlled charger that I've found is at Argos for about £25 which is at least £10 cheaper than any others. Having said all that, Halfords and Machine Mart sell small top up chargers at £10-£15 (Clarke, Draper etc) which are technically trickle chargers but the current is so low that, in practice, the voltage doesnt rise beyond about 13.5v. Not suitable for permenant connection but I leave mine connected to the lighter socket for two-three days at a time and the max voltage I have ever measured is 13.6v
I wouldnt charge a sealed battery whilst still connected in the vehicle unless I was using one of these electronically controlled chargers. In fact I wouldnt charge it with a cheaper charger even if was disconnected without measuring the voltage at regular intervals using a digital multmeter that reads to at least one decimal place in order to avoid any chance of gassing.
Machine Mart sell a digital multimeter that reads to 2 decimal places for about £7
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Claude..thanks for that and very interesting.. I studied the Airflow and Optimate/Accumate site and came to the same conclusion that the latter is far more technically sophisticated than the Airflow and is the same price. They also give a two year warranty.
I e-mailed them and they replied confirming that it was suitable for continous connection with the battery connected. As such I ordered one from them today.
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there used to be a school of thought that recommended a perodic slow discharge (through a light load such as a headlamp bulb or similar) followed by a thorough recharging.
Regarding the above I believe it to be correct. Some 40 years ago I used to work with an old submariner who served when they used batteries for submerged propulsion.
He told me that it was standard practise to periodically drain batteries completely on a rota basis to prolong their life.
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Thanks for the response Alvin. Like your submariner, my Father also swears by a frequent slow discharge of his stored batteries, a practice he picked up from his dad back in the 1940's. What I'd be interested to confirm is whether this approach still holds good today, with modern battery technology, or whether I'm wasting my time (and possibly doing more harm than good).
Regards
RM
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Submarine batteries are traction batteries which are characterised by periods of long discharge (to about 30% charge) followed by a charge to full capacity. Car batteries are chacterised by long periods at about 70%-80% charge with short periods (seconds) of large current draw. The life of any lead acid battery is determined by the number of charge/discharge cycles, the manner of charging, temperature, quality of elctrolyte, mechanical stress etc. In the case of submarine batteries its typically 20-25 years and for car batteries 5-7 years but, in either case, the less cycles the better.
So I've never understood where the idea originates which suggests that introducing a slow discharge to a lead acid battery is good for it or will do anything to increase its longevity. None of the electronic battery chargers which are designed to be left permanently connected include any form of discharge in their charging algorithm. In fact just the opposite, they all have a third or fourth stage which provide a float charge to keep the battery fully charged at all times. (The exception is the Airflow which allows a cycle of part-discharge and part charge but thats a function of its 'on-off' voltage regulated design).
Maybe the idea originates with the first generation of Nicad batteries (1940's) which had a 'memory' effect which acted to prevent the battery being fully charged. This memory was dissipated by discharging the battery. There is a modern legacy of this in mobile phone instructions which frequently suggest allowing the phone to self-discharge, particularly in the first few weeks.
Maybe someone more knowledgable can say why a lead-acid battery would benefit from this.
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I was taught that car batteries are designed to be maintained at near full capacity, i.e. should NOT be discharged on a regular basis (although i can't remember why!). The more times they discharge, the less able they are to hold their charge.
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Several interesting issues in this thread.
DISCHARGING
You must NEVER fully discharge a lead acid (i.e. car) battery fully. If you do, it causes a sulphur precipitation in the sulphuric acid electrolyte. Once the sulphur has precipitated, it is impossible to get it to dissolve again. As a consequence, the battery's power capacity is reduced.
Therefore, a battery that has gone flat once (through stupidity - I've done it too) is likely to go flat again more easily. Buy a new one if it goes flat again.
If you don't believe me, look for the driver's handbook on a new car with a battery that is guaranteed for 5 years, and look for the section which suggests letting your battery go flat once a month by leaving the headlights on overnight...
BATTERIES ON CARS USED ONLY ONCE A WEEK
If you find that your battery which has been standing for a week or two won't start your car, then buy a new one! If you have to call the AA to start it after such a short period and have trouble with your shoulder, buy a new battery from the AA man. Or go to Halfords and get them to fit one for you.
If you have an old car, or one that can be troublesome to start, or a diesel then buy the biggest battery you can fit into the space. Modern batteries tend to be smaller than batteries from a few years ago, so you'll be able to get a bigger and better battery into the same space.
There is nothing for starting my ancient Polo quite like attaching it to the twin batteries of my Hilux with jump leads!
DISCHARGING A BATTERY
Nickel Cadmium (NiCad) batteries can develop a 'memory' if they are not regularly fully discharged. So you should discharge rechargeable batteries regularly (the sort you get in a mobile telephone, rechargeable screwdriver, torch, or the sort you recharge yourself).
(The 'memory' means that although you can recharge it to 100% charge, if you regularly run it down to only 40% charge, you are then unable to access the last 40% of charge. So you are left with only 60% of your battery in operation.)
DIGITAL MULTIMETER
Maplins were selling them for £2.50. You certainly don't have to pay more than a fiver. Useful for checking your points as well (!)
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Mapmaker is absolutely right with his advice not to discharge lead-acid batteries - this can do irrepairable harm, especially if re-charging is delayed. A lead-acid will last longer if it is kept fully charged for as much of its life as possible. The advice about a voltmeter is also sensible. A fully-charged lead-acid should read 12.7 volts or over. A reading of 12.5v is about 75% charged, 12.4v is about 50% and 12.2v is about 25%. 12v or under is 'discharged'.
CG
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And Maplins are still selling digi voltmeters for £2.50. Half price in their 'sale', but they often have them on offer at that price.
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