Monthly battery charger?

[T i m]

A mate has several combinations of rechargeable / battery powered kit (portable tools, mobile radios etc) but doesn't use them all frequently.

So, he would like to be able to power them on for say a couple of hours, once a month to keep them charged up.

He hasn't been able to find a commercial / plug in timer to cover that sort of cycle (7 days typically max) so wondered if anyone here had come up with anything suitable?

Failing finding a production monthly timer, the next step might be a Arduino / ESP type project with RTC or NTP and a mains output relay?

There are a few RTC / NTP examples out here and a mate should be able to tweak such to suit our needs but if something already exists ...

Cheers, T i m

[Harry Bloomfield]

T i m formulated on Thursday :

A long way around to it, but a plug in electro-mechanical time clock set to be on for 1 hour per day, with a second plug in timer set for one hour on per day would turn a charger plugged in to the second one on for one hour, in every 24 x 24 hours, or every 82.2 days. Set the first one to 2 hours on per day and it becomes every 42.1 days, 3 hours would produce every 27 days.

Note, both clocks would need to be synchronised at the beginning, by both just clicking on at the same instant, or you would get weird out of sync on's and off's.

Plug-in time clocks can be had for a couple of quid each.

[Marland]

I haven?t time to check the specs of any at the moment but that sounds similar to the sort of timer that is used for long term time lapse photography. Intervalometer would be the term to start a search on. Obvously capability?s vary with cost.

How long could the timers be set on old VCRs? I think I had one that could bet set for months in advance but it has long gone so cannot check but the PIRA use a hidden one for the Brighton bomb setting it a fair way in advance. Old VCRs can still be found for asking so maybe one could be tinkered with. ICBW but I think mine already had some method to turn on something external like a satellite receiver or cable box.

GH

[T i m]

27 days would be fine I'm sure, as it was only 'about a month' he was looking for. But he asked for 'for two hours' (I think he's noted how long it typically takes for all the batteries to become fully charged). The first one set for 3 hours would initially drive the second for 3 and it in turn would run for it's two plus and hour off. So would that be 8 x 12 hours so once every 8 days (max)? <Confused>

Understood.

So are we talking the straight mechanical clocks here Harry, the ones with the segments or pins round the outside for setting the On/Off times, or wouldn't they be accurate enough. The electronic / LCD / digital timers would probably offer better accuracy assuming they could do so when powered off themselves (free running rather than mains synchronised, assuming they work like that)?

Cheers, T i m

[T i m]

<snip>

Thanks for that. I found some info on a Canon one but that only went up to 100 hours.

I think that would be a bit too 'hands on' for both of us and even an Arduino solution might be easier. ;-)

Thanks for the thoughts though ... it's this sort of OOTB thinking that often *does* come up with a workable solution. ;-)

Cheers, T i m

[Bill Wright]

Just charge the tools up for a two minutes every day.

Bill

[Harry Bloomfield]

T i m submitted this idea :

I was busy watching something on TV, so I didn't think it through properly, I'll leave it to others to double check the numbers. Not a fully formed idea, but a cheap way to do it.

Electrically driven synchronous mechanical clocks will offer best accuracy, I would suggest. They type with pins, or fingers that you flip out.

The electronic type usually run on a rechargeable battery and a cheap oscillator when there is no mains. They can drift quite a lot on battery.

Mains synched ones, will only miss a few mains cycles in starting and stopping.

[Brian Gaff]

Has he considered the Armstrong method? set a reoccurring alarm on something like a smart phone or smart speaker and having all the kit plugged into a socket bar with a switch, alarm goes of man switches on bar, second alarm goes off man switches off bar. These walk will make the man fitter. Of course not to be sexist, it could be a woman. You might have problems training a dog or parrot to do this however... :-) Brian

[T i m]

<snip>

Agreed, however, that would be difficult to manage especially across a range of tools / devices and to an overcharged battery (for storage purposes) was considered better (and more useful when needed at no notice) than a flat / ruined one?

Cheers, T i m

[T i m]

<snip>

Whilst I'm sure that would be better / safer than doing nothing, I'm not sure it would be ideal with some of the intelligent chargers that go though a bit of a routine before they indicate fully charged or even start charging properly?

I think his idea is that a monthly recharge would allow the batteries to self discharge a bit and two hours would be enough for them to become fully charged and the charger lights go green etc (not that he would be there to see it, just that's what he's been doing manually).

That said, there could be a compromise here, say a 7 day timer and a

10 min charge etc?

Cheers, T i m

[T i m]

That's what he's been doing up to now Brian but the gear in question is in an outbuilding and not so easy to get into (security), especially when it's dark or raining etc.

Or you are out for the weekend when you remember to respond to the first or second alarms ... ;-)

In this case it's a man. ;-)

Or kid ... <weg>

Cheers, T i m

[Harry Bloomfield]

T i m formulated on Friday :

A wireless remote control mains socket would work around that problem. I use four of them, one to remotely turn printers on, second to switch several outdoor flood lights on, one to power some decorative lighting indoors and the final one is used to turn some decorative lights on at the far end of the garden. Yet another wireless remote, powers my fibre modem which at the top of the house - it saves climbing up there to force it to reboot.

[Bill Wright]

If the charger was on for a few minutes every day and it detected a fully charged battery, nothing would happen. After x days the battery would not be fully charged so the charger would then charge it.

Bill

[T i m]

<snip>

Except some do (was my point). Some of the chargers use Delta rather than straight voltage values (possibly NiCad / NiMh) and so do need to be on for 'some time' before they indicate a fully charged state. I'm not saying you need to wait for that, just that he does have some iffy batteries and they do seem to take some charging to be considered 'charged'.

Same with my Optimates on LA batteries (and I am thinking of using this sort of solution for my gaggle of Semi Traction batteries).

I agree with Li based chargers.

[T i m]

Again, it *would*, as long as you remember to actually turn it on an off. ;-)

I had one for all the HiFi gear years ago.

;-)

The other problem with that could be the lack of any positive confirmation that the thing has switched? Ok if you see a water feature start up or your floodlights come on but not if your chargers don't actually turn on or off?

I think the best OOTB solution so far might be a 7 days timer with the on time set to the shortest that will ensure even the slowest battery indicates 'Charged'. It just means they will be held at a higher level of charge more of the time (rather than self discharging a bit more between charges).

That or we play Arduinos ... ;-)

Cheers, T i m

[T i m]

Many solutions are a compromise, especially when dealing with a range of rechargeable batteries.

Yup.

Nope. Most of us will have older rechargeable battery powered kit that have 'died' because of a failure to maintain the batteries *at all*.

I have fitted a new battery to one of my motorcycles, only to find it completely flat (and therefore 'dead') when I've next gone to use it. A solar charger on it or a regular re-charge would have saved it.

In most cases, more than the cost of any solution that would go some way to preventing such losses.

The last 'brand new' but dead bike battery I scrapped was £60 retail. My mate has several De-Walt drills that had perfectly good batteries, till he left them uncharged for ages ...

Not only can it be expensive it also mean these things aren't ready for use.

I have many vehicles and even more batteries and they aren't my only hobby. Automating some of this will same me (and my mate) money in even the short term.

Cheers, T i m

[T i m]

<snip>

Nope, they really are.

Quite (and the whole point of the thread).

I didn't know you lived to close to be able to know that?

See, when you have several vehicles you often don't know if / when you might use any one of them as it depends on a myriad of variables, many of them external. Disconnecting the batteries would have made no difference as none of my bikes have any kit running when the ignition is turned off. Bringing them indoors may have helped a little [1], but not as much as charging them once in a while ....

Because sometimes you do? You buy a battery drill and then later buy a better / faster / more powerful / impact one. Then one day you need two drills on the go and find your first one is now dead.

Corded motorbike? Corded walkie talkies? Corded torches?

Good. ;-)

Cheers, T i m

[1] I take the battery out of the 250 scooter because it's small, sealed and very easy to do. Getting the battery out of the BMW R80 or kitcar is less so.

[JameBUYv]

It is interesting. Tell to me, please - where I can find more information on this question?

[T i m]

<snip>

Wassup, can't do the code, don't know how to attach it to an email or don't actually have a clue what people who aren't you might want to do? ;-)

Cheers, T i m

[T i m]

<snip>

I may well do, thanks.

Aww <blush>

I do like to keep an open mind on things, that's for sure as it generally allows one to be more flexible / adaptable.

But hey, you already knew all that didn't you ... even if you don't enjoy such things yourself ... [1]

Cheers, T i m

[1] Most other people who have contributed to this thread so far have been positive in offering suggestions to resolve the question, understanding and accepting that the scenario is fairly specific.

You on the other hand seem to (as usual) insist that the scenario outlined isn't valid or can be replaced with alternatives (which they can't for 100 other reasons you could never accept).