I guess if I connected my boiler, and if it had something that required what you say (possibly not as it's an old Baxi system boiler, non condensing, non combi, made before 2000 as it was here when I moved in), I'd need to strap the two together. But that would short out half the UPS output, so I'd have to give the boiler a fake earth, meaning touching it when on battery might give me a 110V shock if I touched a grounded washing machine. No, that wouldn't work either, as the pipes are most likely connected to its chassis and probably grounded elsewhere in the house. Perhaps a small isolating 1:1 transformer just for the boiler? Then I could strap one leg of its output to earth.
Correct, but if there was an issue somewhere (a cross fed circuit) and someone was playing with what was assumed to be a fully disconnected circuit ... ?
I think it's the same idea of remote earth bonding of anything that 'could' lose it's earth somehow.
I think the idea of bonding the output of a generators neutral to earth is because it's otherwise 'floating', rather than the neutral being referenced to ground as I believe it generally is (here in the UK).
Yeah, they are handy. That or you run PowerChute or apcupsd (as I do) and monitor it that way.
Ok.
If yours is the same 'black' one as mine it's normally two 12V x 17Ah (or similar) mobility / golf cart / UPS SLA batteries. I know because I 'borrowed' the batteries from my Dads mobility scooter to test the UPS when I first got it (he had passed away by then).
Yes, I've had those in the older beige plastic APC units.
I'm not sure about that as they would have to be in series and that would affect the voltage (unless there was independent charge management when connected in parallel)?
Car batteries would do but you wouldn't want to run them anywhere near as low as you would with proper deep discharge cells. But if you weren't using them as such, often or deeply they could be a cheaper solution. ;-) [1]
Yes, I think initially a pure sine wave UPS to be quickly followed by the generator etc.
And does it generally come on much would you say?
Most of ours have only been a matter of minutes but I'm trying to plan to have some lighting on (and stay on instantly) for an hour at least.
Yes, Dad was having regular power disconnections and it cost him 600 quid to have a corrupted Mac drive recovered. They (the electricity board) gave him a UPS to protect him after that. ;-)
Funnily, I have several 660VA UPS's here that I meant to put on my server and workstation but the only person who has one atm is my Mrs on her PC. ;-)
Ok.
No, I've had a couple of reasonable LED lights blow and they tripped the lighting MCB both times.
Cheers, T i m
[1] I used to race (after designing and building) an electric 'motorbike' on two std car batteries and they lasted a full race season with no ill effects. ;-)
If you're that paranoid, then just connect all the earths together somewhere. Or don't use plugs, just switches. You'd need a two way switch with an off position, or if they don't make such a thing, a two way switch and a normal switch for off. Two single switches would not be good, as feeding mains into the output of the UPS might scare the shit out of it. And that last thing would also cause problems if you cross fed something. The answer is not to cross feed something.
I assume the UPS we both have references the live and neutral outputs to ground. I tested them with my multimeter and got -110 , 0 , +110. But perhaps they were floating and the meter was just guessing? One of us would have to try connecting a small load between live and earth of it's output to see if it clamped it.
I'm not familiar with the technology of fibre, but there only used to be one with ADSL broadband. Why are they now separated into two? The first one (Openreach) gives an ethernet output. So does it do everything except wireless transmission and firewall?
I've not installed drivers, I just plugged the USB cable from the UPS into my computer. Windows detected it as a battery and acts accordingly, sleeping and shutting off monitors earlier, and shutting down or hibernating (I can't remember which and hope it's shut down) if the battery level gets too low. Just changed it in the control panel, it now shuts down if it hits 20%. IT's Windows 10.
Yes it's a black APC Smart UPS 1500VA, so I assume identical. I could have sworn I fitted four batteries. I can't look at it now as the computer is on top of it in a small area beside my desk and I can't easily get to the back of it. I could be thinking of another UPS I had years ago, or one I repaired at work.
I just assumed you could connect as many as you liked in parallel. The UPS presumably wouldn't care, and just find its battery lasted for ages, or would read the battery level slightly differently? Does it just go by voltage or does it intelligently know that a battery of X capacity with X load and X voltage has X% left? Presumably it expects the voltage to gradually fall as it gets emptied, and a much larger battery would fall slower.
Modern car batteries don't care that much if emptied. I had a car where I flattened (completely by using a fridge with no cutout) the battery many many times and it worked just fine. A mechanic told me the cells are constructed differently nowadays and don't collapse.
I was wondering if it was always on UPS (which continually recharged the battery off mains), even if the mains was ok, so it didn't get any surges through to the sensitive equipment.
It comes on at about 80% load (4 out of 5 load LEDs) when mains is present, which in my case is if all the lights in the house are on and the computer, or I'm playing a game which uses the graphics card heavily. I think it always comes on if running off battery.
I'll only do that if it ever happens.
Why did she get one first?
I don't have any circuit breakers. I've never had an LED "blow" either. They just begin flickering and I dismantle them and find one of the LEDs keep going open circuit. The original CREE spotlights were terrible, they ran too hot.
Cool! Were you racing against other EV bikes or petrol ones?
I avoid danger which is likely, not something with a 1 in a million chance. Do you have a statistic for the number of people killed by mains being where they thought it was off? I bet it's a hell of a lot lower than being run over by a bus.
Dunno how it works. Maybe there are two invertors? Maybe one invertor that makes a +ve and -ve output and has the earth connected in the middle?
It was exactly half on each side, so I guess it wasn't just floating.
Assuming it is 110-0-110, I guess you have a handy 110V supply. If it doesn't mind you drawing power off half the cycle only. If it's designed to be American then perhaps that would be ok, as thy have two voltages present in their houses.
I really couldn't care what the chances are mate. 1) I'm not asking you to do it for you. 2) I'm not asking for you to do it for me. ;-)
Ok.
Again, I'm a utilitarian mate and so practicality and simplicity come over 'looks' every time (when it comes to 'utility' especially).
So, two 13A surface mounted sockets fitted over the CU labeled 'Upstairs and Downstairs lights' and above them, two junction boxes with cable outlets and short lengths of cable with 13A plugtops on them. To have it as 'normal' you just plug the plugs into the sockets. To insert the UPS into the upstairs, downstairs, with two UPS's or one bigger feeding both, you just 'Plug and play'. ;-)
It's also easier to buy what you know exists than to buy what you don't and I could probably get all the bits mentioned above for under a tenner (and I've probably got most of the stuff here anyway).
Seeing people talking about safety is as repulsive to me as seeing someone doing a shit.
Do you mean you'd connect the two sockets to the output of your CU's lighting breaker, then the plugs to the wires that feed the lights. So you plug them into the sockets and it's as it was? So to use the UPS you have to plug those plugs into the output of the UPS, which presumably you've fitted with more sockets? And you plug the UPS into the sockets where the lights were?
Yes, because they *normally* have the modems built in.
Don't know, just seems to be what they do.
Yes, but I don't think that is taking the fibre itself is it? Normally the fibre goes to the local cabinet and they still use the copper cable to your new modem.
The modem? I's say it only does the modulation and demodulation and the router does all the rest (WiFi, NAT, Firewall, switch).
Ah yes, I had forgotten that later Windows has reasonable UPS support built in.
Cool. If you had more than one PC on the UPS you could also get the main one to shut down if you ran apcupsd on both / all.
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Yup. ;-)
No, it could well be (4 x 6v) and I've even seen straight 2V cells uses in UPS's but that one seems to take the 2 x 12V.
It is possible, as long as the electronics was there to cope. Like when you add an auxiliary battery to your car or want to charge the caravan battery from the towing vehicle, you really should use a dual output alternator or at least a split / charging relay.
Yes, that's the problem wiring most batteries in parallel.
Not if they are just directly connected in parallel etc.
Yes, that bit would be ok, as long as the control circuitry could manage each of the battery paths intelligently.
I believe most std car SLI (Starting, Lighting and Ignition) battery's are not designed for any real depth of discharge.
I don't believe so.
Ah, 'a mechanic'. ;-)
How well they can recover from that sort of level of discharge can be a function of how quickly you get round to charging them back up again. Leave it too long and the plates can start to sulphate and can be difficult to recover. Also, the 'Calcium' LA batteries to recover better than straight LA (but should still be avoided).
Ok, thanks.
Makes sense.
I'm guessing you have never been married mate? ;-(
Yes, that's the other thing. Whilst they (LEDs) don't give off anything like the heat of an incandescent, most of them still have reasonably sized heat sinks and can get pretty warm.
Cheers. ;-)
Only EV's and not only two wheelers. Basically the rules were very open. The only real limitations is that it had to be reasonably 'safe', have an easily accessible are readily recognisable electrical cut-off and carry a maximum of 25kG's worth of battery. After that it was pretty well up to you. I would say the majority were feet forwards
4 wheel streamliners but they didn't fare so well on the twisty go-cart circuits we sometimes used with their lightweight cycle orientated wheels. It was then the two wheelers really came into their own and the race that I was pictured in on the link I actually won (my first and only), beating the previously undefeated master of EV's, Cedric Lynch. ;-)
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To be fair the 'only' reason I beat him that day is I got the drop on him over the last couple of laps (in a 1 hour race) and he wasn't able to catch back up in time (partly again because of the twistyness of the course).
To junction boxes containing the original ends of the two lighting rings, yes.
Yes, that's the idea anyway.
I have made up many IEC male to UK 13A trailing sockets so yes.
Yup. Either two smaller UPS's (that typically use a single 12V battery so easily replaceable by a bigger / cheaper battery externally) or one bigger one running off just one of the lighting ring MCB outputs.
I was also thinking if I should run the UPS outputs though 6A MCB's as I'm not sure what would happen to the UPS if a lamp failed in a way that would typically trip the CU MCB? I know if bad enough it could blow the fuse in the 13A plug but it wouldn't be so easy to 'reset' as an MCB?
rs, a stereo, 2 printers, and 2 internet routers (for some reason there'= s a "fibre router" from BT Openreach aswell as the one my ISP gave me).
be one with ADSL broadband.
Correct. Apart from Fibre to the premises, which I don't have.
Sounds about right. The BT engineer told me it's so they can tell that = everything in their wires is working fine and not wonder if it's your IS= P's or your own router not connecting right.
into my computer. Windows detected it as a battery and acts accordingl= y, sleeping and shutting off monitors earlier, and shutting down or hibe= rnating (I can't remember which and hope it's shut down) if the battery = level gets too low.
I'm pretty sure it worked quite a few versions ago with another USB UPS.=
%. IT's Windows 10.
You mean the computer with the USB cable form the UPS could tell the oth= er computers to shut off?
ve got some incandescent bulbs left, but as they and the CFLs wear out I= 'm replacing stuff with LEDs.
ng fan), you can add additional batteries to them as required, just use = car batteries.
es, I can't remember).
s the computer is on top of it in a small area beside my desk and I can'= t easily get to the back of it. I could be thinking of another UPS I ha= d years ago, or one I repaired at work.
I may have bought something different, something that was the right volt= age and fitted inside it. I don't remember not having enough connectors= but I might have just added some I had kicking about.
You don't have to. That's only to stop you running all the batteries fl= at with the caravan lights then not being able to start the car. When t= he engine is running, all the batteries are in parallel. When you stop = at a campsite, the starter battery is disconnected from all the loads yo= u're using.
A similar strange thing I hear people saying is you mustn't jump start s= ome modern cars. Something to do with the uneven voltage coming form th= e donor car into the electrics. But I have two problems with that theor= y:
1) Why is it any different than when the car you're trying to start is r= unning?
2) I never start the donor car when I'm jump starting anyway, it's not n= ecessary. If the good battery can start its own car, it can start the o= ther one. The amount of current drawn by the empty battery charging up = when it's only given 12 volts is bugger all. Car batteries charge at ar= ound 14 volts.
r ages, or would read the battery level slightly differently?
ry of X capacity with X load and X voltage has X% left?
d, and a much larger battery would fall slower.
I don't think it would matter. It would say "you have 30 minutes runtim= e left", then 10 minutes later it would say "you have 29 minutes runtime= left" and wonder why the battery isn't getting tired very quickly. It= would still have a rough idea when the battery was getting very low.
atteries (presumably in pairs in series) wired into it.
utout) the battery many many times and it worked just fine.
Well it happened. And I remember doing the same thing 20 years ago and = the second time the battery was f***ed.
don't collapse.
Nope, the battery was perfectly fine after draining it too low to even t= urn on dash lights about 15 times. It charged up as quick as it always = did, and had the same capacity, as the fridge lasted as long as it shoul= d.
esent, which in my case is if all the lights in the house are on and the= computer, or I'm playing a game which uses the graphics card heavily.
Not sure if it's a thermostat inside it or if it just knows that certain= loads and tasks require cooling. Probably not just a thermostat, as it= engages the fan immediately the invertor comes on. The cooling for nor= mal usage might be thermostatic though - it should be, as it needs to co= me on earlier at a higher ambient temperature.
Never known a woman desire a UPS....
er. They just begin flickering and I dismantle them and find one of the= LEDs keep going open circuit. The original CREE spotlights were terrib= le, they ran too hot.
Anything electronic that's too hot to keep my hands on I consider badly = designed.
This is interesting:
Typical efficiency Steam Engine =3D 8% Petrol Engine =3D 20% Diesel Engine =3D 40% Conventional Electric motor =3D 75% Cedric=E2=80=99s electric motors =3D 93%
I wonder how efficient the motors are in electric cars generally availab= le on sale to the public?
So superior driving as opposed to superior design :-)
-- =
Why does the law society prohibit sex between lawyers and their clients?=
To prevent clients from being billed twice for essentially the same serv= ice.
Yes ... Basically they talk to each other over the LAN and so a slave will know when the master (and so themselves, if also powered from the UPS) is running on battery and so also initiate a power down (using their own config file timings).
I set this up for a mate who has three groups of PC's. One group is next to the server with a 1500VA Smart APC USP and the other two groups share 650VA IPS's between them. All the network gear is also powered by the UPS's (of course) and I think I've set it so that ALL the slaves get their clue from the master of their group (just in case the LAN fails between them). They have used it a few times now when the building was having some refurbishment work doing.
I would. *You* don't have to. ;-)
Mope. If you just had them in parallel and connect the caravan or aux battery up flat, then the alternator will see the low voltage / resistance of the flat battery and effectively charge both at the same rate. The vehicle battery will then risk being overcharged if for no reason than it would see a higher voltage from the alternator than the more remote aux / caravan battery.
Not ideally (see above).
Yes, the split charging relay can do that but it should do more than just that.
I'm no expert on that sort of thing but I'm thinking spikes and such might not be good?
Depending on the size of the assisting battery, the charge state of the slave battery and the resistance of the connection between them.
Yup.
If the UPS electronics preempt the runtime from the theoretical battery capacity (new) and the measured discharge rate then yes, you would just get a false predicted runtime and the UPS would still initiate shutdown at the preset threshold.
Ok. I'm guessing they wouldn't make batteries *designed* for deep discharge and they be different from the SLI role on cars? Most deep discharge calls are tubular in construction and generally have thicker plates. Thicker plates resist damage and live longer better than thin ones and cars (SLI) sacrifice durability for energy density.
And you measure it's capacity accurately (constant current load and the right temperature) before and after? ;-)
I have an instant capacity reading meter and even that will show an over discharged battery to have reduced capacity. I'm not saying it will be masses or instantly but that is how I believe it is.
Possibly both? Thermostat when running on mains and all the time when on battery?
Yeah.
Makes sense.
You don't know my Mrs (G7ICX). ;-)
Agreed (within reason, some stuff needs to be 'small' for example and so might run hotter than it might otherwise for that reason).
He is a smart cookie that's for sure!
I used what was likely to be a very expensive (MIL grade) DC motor in my eBike because that was the best I could find. I have no idea how efficient it was but I didn't have much choice. When we were racing, Cedric was in the beginnings of starting his motor production so no one else could really get hold of one.
Yes and no ... in that _one_instance I guess it was but to be fair Cedric sort of brought it upon himself. What he would do is just keep a reasonable distance in front of the person running second, that way he never showed his hand. We would go away and make say a 5% improvement to the performance of our machines and he may have 30% still in reserve over us. ;-(
Except the day I caught him out I went past him at a rate that he couldn't physically catch up (in time) because his top speed wasn't high enough and because the circuit shape and looseness suited his machine even less than mine (again limiting his speed). ;-)
I know, which isn't to be advised, especially in that circumstance.
In the case of two batteries connected in parallel (or even individual cells), there is a very good chance that they will have different characteristics. Therefore, one cell / battery may attain a full charge but because the voltage is depressed by the partially charged battery it is tied to, the fully charged battery will *also* continue to have a charging voltage applied to it and become overcharged.
Fact mate.
Nope (see above).
Good in theory. In practice however ... any voltage over the charged batteries resting voltage will cause it to continue charging and therefore, potentially overcharge.
It doesn't need to because no two batteries need have the exact same characteristics.
Not quite but yes, it would need some 'management'.
Not the same as connecting up another battery.
Nope, just ohms law mate.
Correct, subject to the size and charge state of both the batteries of course. A fully charged large 12V battery connected to a flat motorcycle battery may charge it reasonably well (to start with anyway).
Possibly (depending on why the dead battery is dead and the size and charge status of both batteries).
It can, yes.
Probably not, assuming there isn't a shorted cell etc.
As have I. Not sure that proves any of your assumptions though?
Nope, For a battery terminal voltage to raise naturally it has to 'accept charge'. Therefore at any point between it being flat and fully charged there will be every voltage in between. So, if one battery is sitting at 13.6V and is connected in parallel to one at
11.5V, one battery *will* charge the other (it must).
And why you have to allow for such deterioration when speccing and installing a UPS.
So you mean the 'current capacity in Ah' based on it knowing (or calculating via monitoring) the charge and discharge process?
I think what UPS's do may depend on the UPS themselves (firmware etc).
Voltmeter.
? The terminal voltage on a battery is normally a function of the load upon (internal resistance) it and it's state of charge.
That doesn't mean it's not true in general. Batteries are 'designed' for different roles and those rolls require different designs. A battery 'designed' to run a submarine, fork lift or milk float will be a very different beast than one designed for a car SLI.
I don't believe so. Modern car battery's tend to last less time than they did many years ago. Partly due to the loads put upon them and their construction (greater energy density for their weight and size v heavier construction, better lifespan and tolerance to over discharge).
Yup.
It sounds like it to me. If by treating it that way reduces it's life prematurely then by definition you are 'killing it'.
Deeper levels of discharge are supposed to reduce the cycle-life proportionally.
Leisure batteries are somewhere between SLI and semi traction although many tend towards SLI.
Yes, because you may still be within your 300 cycles.
So you didn't do it many times and you did see the capacity drop. QED?
Well, we were indirectly. ;-)
Computers can but house lights won't and I'm not sure if all UPS's disconnect before they sense the battery is at a critical low charge threshold (say 30%).
We often determine that threshold, not it as such.
Correct.
And given the battery capacity at the time. In two years time your 20% could be insufficient.
Or it gets the fan running to try to preempt the heat?
Ok (I like that).
Cool.
UK Amateur Radio call sign so close. ;-)
Likewise.
Soldering iron? In a PC, or electronics in general, nothing. ;-)
It's all to do with managing the risk to both me and others. If by ensuring the earth is continuous at all times may stop someone else being electrocuted and it's easy to do then I will. Just in the same way I'll generally not take my motorbike out in the snow or ice.
They aren't 'safe' by definition as they (mostly) only have two wheels (so naturally 'unstable') however, we often sacrifice raw safety when we want to achieve other things, like get to work though heavy traffic or just for 'a change'.
We couldn't object to our daughter taking her motorcycle test as she spent much of her youth either on the back of mine or going round a track on her 50 then 80cc motorcossers. I'm not sure if her later riding to work on her 250cc motorbike was any more dangerous for her then being 60' up a tree with a chainsaw or feeding a tractor PTO driven chipper?
She's recently upgraded to a Suzuki GSF600 'Bandit' and seems to love it. ;-)
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