Kitz Forum
Computers & Hardware => Other Technologies & Hardware => Topic started by: Weaver on February 18, 2016, 11:24:36 PM
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I have a couple of UPS already, an APC one £90 can't remember exactly and another one whose pedigree I don't recall just now.
I'd like to get a more beefy device with a longer run time. It's just to power
* three modems, DLink DSL-320B-Z1
* an Ethernet firewall/ router (Firebrick FB 2500 is indeed very low power)
* a HP 1820G switch
* a Zyxel WAP
and no PCs, dealt with by other ups.
I need it to have a healthy runtime sufficient to survive a power cut of several hours, or until I can get some help getting the generator going (extremely rare occurrence).
I haven't got anywhere near doing a current budget for that lot or any further towards fixing an an actual runtime. I just know I want to get highly reliable kit, above £100 perhaps rather more if I get better value for money that way.
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I have two UPS with one used in a very similar to the way you intend (FTTC modem, router, 8 port switch and a QNAP NAS with a single disk). It's a APC Back-UPS CS 350. It says the estimated run time on that is just over an hour.
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@jelv sounds like your ups is in the same class as mine, but something I have running must be more of a current hog. Perhaps the old switch a Netgear 24-port unit. I forgot to mention the double mains filtering on the output of the ups, before the modems, a Tacima unit and a Belkin AV mains filter, perhaps that wastes a lot of energy.
So I'm looking for something a lot more heavy duty than that class of kit, with substantially greater runtime.
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I have two UPSes - a second hand APC 1500 unit (1kw) and a relatively new 800 (480W). I think they are both excellent units and given how much cheaper the Cyberpower unit was I would definitely buy another. The APC units are in my experience pretty bomb proof as long as you don't mind exchanging expensive batteries every 2-3 years.
I would describe my APC unit as fairly meaty, it certainly weighs a lot and it looks after 3 PC's and all my network stuff and gives enough power for a short outage and to allow everything to shutdown properly. In past I have bought second hand APC units off ebay with new batteries and they always seem to last OK.
I am no UPS expert but from the runtime graphs for my UPS you will get a max of 100 minutes at 100W so for the kind of duration you are talking about even with a tiny load you are going to need quite a big unit.
I am guessing look at the runtime graphs (http://www.apc.com/products/runtime_for_extendedruntime.cfm?upsfamily=165)on the manufacturers websites based on your calculated load.
A quick look suggests that for a 50W load for 120 minutes you need a 2200 VA UPS, that IS meaty (and expensive). Are you sure you need so long?
GL!
Chunks
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> A quick look suggests that for a 50W load for 120 minutes you need a 2200 VA UPS, that IS meaty (and expensive). Are you sure you need so long?
No. ;D is the honest truth.
Thing is, no one wants to get up in the dark, starting generators up when the weather is vile, so if I can sail through a short outage then that would be very welcome.
In the daytime, we need time to get the generator going first, and then it needs to be able to cover the time when the generator is being refilled later on.
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Since I can't combine them (HCF!), I could increase capacity by assigning the devices to individual UPS's. Highly undesirable in so many ways, and very wasteful. I need to find out the real power draw of these devices. Perhaps I'm missing something here. Basically all I need is a really really big fat huge battery, lots of kg of something.
There was a thread while back where the backup battery capacity in a telephone exchange was discussed.
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Does anyone know anything about these people?
http://www.powercare.co.uk/product/netpower-2000va-ups
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Go for it (http://www.powervault.co.uk/) :D
C
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Referring to that link I posted earlier, powercare, I can see VA and W, but I'm not interested in how high the current delivery can be. I want J, to get to the run down time. Am I going mad? I just can't see it anywhere.
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Sorry clunkers, never any sun, Sod's law, when you need this. It's always as black as night.
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How old are the batteries?
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I've got a Smart-UPS 1500VA LCD 230V at home, and we also have one at work, the batteries are not expensive so long as you don't buy genuine APC ones. I recently purchased two replacement batteries (it takes two batteries) for the works unit and they came to £53 from Allbateries.co.uk
At home I have a server, my modem, 16 port switch and my projector running off of it. The projector is currently off (standby) and run time is estimated at 123 minutes with a load of 9.1%. Unfortunately it doesn't report the load in Watts, at least not that I can find quickly, but the server draws 80w to 100w roughly, the switch 6w, not sure on what the router draws, and there is another bit of equipment which draws 8w.
My home UPS is 5 years old and I've never replaced the batteries, the works unit has had them replaced twice, these UPS's carry out self tests and set off an alarm when the batteries need replacing, which is really easy to do and can be done with the equipment still powered up.
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Worth noting that the self-tests on the APC units (used them for the best part of 20 years) are largely useless in terms of warning you of battery degredation due to their very short duration. By the time it generates a warning the battery is probably down to 30% of its initial capacity.
The "Calibration" function is the one you want to use every 6 months or so as that will accurately test the battery capacity. That's where the "Runtime" estimate comes from.
I have the same model (no LCD display) and for the load you're pulling then 5 years is about the maximum time I'd want to use the same batteries. Obviously this doesn't just depend on how many power cuts you have, it depends on the limits you've told the UPS to switch to conditioning the mains input (which requires battery usage). We have (historically) had a lot of overvoltage here so that has an adverse effect.
For the kit we're talking about here then you can more or less equate VA as W as power factor will be close to unity - probably about 0.95, maybe a fraction lower depending on the number of mains fans. The Powerchute software shows you capacity as a percentage of 1500VA on the UPS status page.
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Have you considered the option of an inverter and a big leisure battery to provide long period power while keeping the UPS to cover brown-outs and short duration failures? It would mean powering things down to swap over. Extending the run time of that option is just add another battery.
Add an 80A solar panel and during daytime it would extend the run time considerably!
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@Rizla, thanks, I'll have to find the calibration option and give it a go. Power at home is pretty good, very few power cuts or over voltages.
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> Have you considered the option of an inverter and a big leisure battery
Jelv, I think that that's an excellent idea, but it would have to be a zero hassle zero maintenance setup. It's in an office environment. You possibly know about my health situation and physical limitation, which rule out sensible solutions that normally would be practical for health people.
> Extending the run time of that option is just add another battery.
Am very sorry, am not following you, :-[ what add them in series?
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I’m currently using a CyberPower CP1500EPFCLCD rated 1500VA/900W which I’ve had since March last year. I mainly suffer from sort interruptions and it has performed faultlessly in those circumstances. Since I’ve had it we haven’t had a lengthy power outage ( :fingers: and touches wood), but some have been at least of an hour’s duration.
With just my modem/router, time capsule, NAS, DECT base station, analogue telephone adapter and Raspberry Pi connected it reports a 3% loading and a battery run time of 143.5 minutes. With my Mac Pro and thunderbolt drives connected the loading is 18% with a lesser battery run time of 60 minutes.
The CyberPower runs very quietly unlike some of my previous UPSs which have suffered from annoying hum. I’ve also had issues with two previous APC models going to battery for no apparent reason and never reverting to the mains.
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Am very sorry, am not following you, :-[ what add them in series?
No, parallel! But I'm not sure if you would need to. The battery inside my small UPS is I think a 7Ah motorcycle type battery. Leisure batteries of around 100Ah are very common (around £75 for a 120Ah battery (http://www.amazon.co.uk/SuperBatt-Leisure-Battery-Caravan-Motorhome/dp/B00WPZFAXK/ref=sr_1_4?ie=UTF8&qid=1455887545&sr=8-4&keywords=leisure+battery)) and it's easy to find ones up to 200Ah.
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@jelv if the voltages on the two batteries aren't exactly matched and you connect them in parallel, then there's just going to be a huge short as the voltages try to equalise and current flows from one battery to the other with only the internal resistance to limit it!
Am I going mad? Apologies if so.
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@jelv if the voltages on two batteries aren't exactly matched and you connect the PM in parallel, then there's just going to be a huge short as the voltages try to equalise and current flows from one battery to the other with only the internal resistance to limit it!
That was my initial thought too :)
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Hmmm... yes you'd need to put together some circuitry for that.
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;D
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But looking further you can get 24v inverters so you could go series.
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What wattage of output would you need?
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I've just found something a bit different - a UPS that you connect to your own battery: http://www.sunshinesolar.co.uk/khxc/gbu0-prodshow/CSC2000.html
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I don't think we've actually established the power he requires?
Weaver do you have one of those plugin power meters - goes in between plug & socket & usually shows :
Voltage, Current, Watts, Volt Amps, Frequency, Power Factor & power/money used.
If not then PM - I probably have one lying around I can send you.
Once we know what the peak power requirements are then its easier :)
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That's true, I don't know what the current consumption of that little lot is
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@jelv well spotted. I just need a battery charger to keep the leisure battery charged up.
Thing is, we're trying to invent the UPS when one already exists. I've noted that some UPS's have extra packs that can be used to extend the runtime.
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Amusingly we've just had our first powercut in the last 2 years now. Couple of minutes duration, hundreds of alarms going off :(
I had typed some stuff out but this machine* isn't on a UPS but basically it comes down to :
Remember to factor in the inherent losses in transformers for costs and remember the losses only get worse the more its used (hysteresis/eddy current losses). My 13 year old SmartUPS1500 eats 60W power with no load, fully-charged new(ish) battery, gets a bit worse each year.
*machine is used as a Steam Link base unit, & if the link got activated during a powercut (like someone playing elsewhere on a cheap lappy) then whatever it was connected to would go flat very damn quickly :D
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I actually can't take over the whole of the desk, and I can't physically do the work to invent a ups, so I'll have to stick to commercial ones that have expansion packs to boost the runtime dramatically. We have our generator after all.
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I actually can't take over the whole of the desk, and I can't physically do the work to invent a ups, so I'll have to stick to commercial ones that have expansion packs to boost the runtime dramatically. We have our generator after all.
Well you may not need a UPS with expansion packs if you do a worst-case test in terms of power consumption while streaming/downloading to wireless clients. ie max it out.
I suspect you may need to put the WAP on a different UPS to get your required runtime.
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I can certainly put the WAP onto a separate UPS, but then I'm not sharing power draw efficiently. Basically whatever piece of kit dies first, it's the end of the whole party.
Does anyone know whether or not WAPs are thirsty?
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Do you think my runtime ideals for say 300W are remotely doable for less than say £500?
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I can certainly put the WAP onto a separate UPS, but then I'm not sharing power draw efficiently. Basically whatever piece of kit dies first, it's the end of the whole party.
Does anyone know whether or not WAPs are thirsty?
considering that wifi on a phone/laptop kills the battery, I'd say theres a strong likelihood of them being relatively thirsty.
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@loonylion - this Zyxel runs at 5 GHz and 2.4 GHz simultaneously. So it might well be thirsty.
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would it not make more sense to invest in a generator autostart system rather than trying to get multiple hours of battery backup for half a dozen different devices?
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I find it difficult to locate C (coulombs) or J. I want to know how much energy or charge is in the store if I am going to get a rundown time. The manufacturers are very keen in advertising VA or W, not surprisingly because it determines how much kit you can plug in to the device, provided it doesn't die from energy starvation before the kit has had enough time to shut down cleanly, the whole point.
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I find it difficult to locate C (coulombs) or J. I want to know how much energy or charge is in the store if I am going to get a rundown time. The manufacturers are very keen in advertising VA or W, not surprisingly because it determines how much kit you can plug in to the device, provided it doesn't die from energy starvation before the kit has had enough time to shut down cleanly, the whole point.
Unless you have a real need to keep going for hours (which you will find expensive), the main reasons for having a UPS are:
- To allow a clean shutdown when the power goes.
You will need a "smart" UPS and something to monitor it.
I use apcupsd with the master connected to the UPS and slaves polling the master. - To protect your kit from power fluctuations when the mains goes off, on, off ... which happens here every six months or so. This can fry a computer.
Has not happened to me since I started using a UPS.
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> Unless you have a real need to keep going for hours (which you will find expensive
I don't want to pay more than £500, and it's crystal ball gazing anyway as to how long a power cut is going to last, as it might simply need us to pull our finger out and get the generator on. Crystal-ball gazing is difficult because we don't get power cuts that often, so don't have enough experience. I don't have anything to monitor shutdown, such PCs have their own separate APC UPSs for that, not under consideration here. This is just about keeping modems alive to keep away the wrath of the DLM Gods and then keeping the LAN and Internet up, for convenience.
I wonder if I would get more value-for-money (more J/£) from eBay. Sounds like a recipe for frustration and knackered batteries.
So I suppose I'm most interest in what I can get that is fairly expensive and gives lots of C (ie A h) can't help sticking to the SI units.
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Ah, sorry, I missed your already having UPS equipped PCs.
Powering (generally) 12v DC kit direct from batteries might be the way to go. Camper van / motor home / caravan technology springs to mind. Visit a breaker?
I can not remember if I bought my UPS new or second hand, but the replacement batteries came from Ebay. Not the cheapest, but significantly cheaper than APC branded replacements.
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> Powering (generally) 12v DC kit direct from batteries might be the way to go. Camper van / motor home / caravan technology springs to mind.
;D
Do you have any experience of such a thing Adrian?
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Do you have any experience of such a thing Adrian?
Only in that I have a camper van with the usual main and leisure battery arrangement, and can safely power 12v devices when the camper van is plugged in to the mains.
Something like this http://www.ebay.co.uk/itm/Caravan-240volt-Mains-to-12volt-20Amp-Power-Supply-Battery-Charger-PO120-/151701419065 might do the job for you. A visit to a breaker might well be a lot cheaper.
I do sometimes look at the burgeoning number of PSUs (2 router/modems, firewall, Samknows box, phone base station, access point, disk caddys, ...) plugged in to extension leads and wonder about a single 12v DC supply to rule them all.
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> I do sometimes look at the burgeoning number of PSUs (2 router/modems, firewall, Samknows box, phone base station, access point, disk caddys, ...) plugged in to extension leads and wonder about a single 12v DC supply to rule them all.
Indeed. Would they be happy running off 12 V ? (Too high for some?)
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> Only in that I have a camper van with the usual main and leisure battery arrangement, and can safely power 12v devices when the camper van is plugged in to the mains.
Apol for being thick, :-[, but does that mean that you supply miscellaneous kit with a fixed 12 V from one device which in turn takes its power from 240V mains ? (So you get rid of all the usual individual little mains three pin mains to DC PSUs?) Or does the device take power from a battery and AC mains?
I've managed to confuse myself, as its late, I'm half asleep and the (NHS) drugs should be kicking in.
This could be the way to go?
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Yes, I am talking about one device+battery that can feed multiple 12v DC devices.
Only 12v DC devices, as others might expel their magic smoke.
Sorry you need NHS drugs, but I hope the side effects are pleasant. I am about to remove the cork ...
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So I would need an efficient inverter (covered earlier I think, in a different subsection of the thread). As I have kit that requires AC, and has no removable DC brick. So inventing the UPS again, I'm afraid.
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I find it difficult to locate C (coulombs) or J. I want to know how much energy or charge is in the store if I am going to get a rundown time. The manufacturers are very keen in advertising VA or W, not surprisingly because it determines how much kit you can plug in to the device, provided it doesn't die from energy starvation before the kit has had enough time to shut down cleanly, the whole point.
Batteries are always measured in ampere hour capacity. Never seen one measured in joules as joules are rarely used as a unit of measure in electrical design. The reason is that battery capacity varies as a function of discharge current (Peukert's law if you're interested) and temperature.
Working out capacity in joules (if you insist on doing so) is simple enough.
One amp at 1 V for one hour equals 3600 joules.
Lets take the UPS I have as an example :
The batteries are 12V and are rated at 18AH so that's 12V at 1A for 18 hours, so 12 x 18 = 216 then multiply by 3600 and you get a capacity of 777600J. Edit - there's two of them in series so bear that in mind in the example - ie there's double the capacity (and voltage) one battery has but the same peak current.
However that's a pretty useless measure in electrical terms.
In reality all you need to know is the current drawn by the load and the capacity of the batteries in ampere hours. You simply divide the capacity by the load and that gives you the time to completely deplete the battery.
However as its lead-acid then you're looking at probably 20% voltage drop between 100% charged (12V) and 30% charged (10V) so you've only got 70% usable capacity in all likelihood*. Now you also have to factor in the efficiency of the inverter/transformer etc. which we'll assume isn't junk so lets call that 85%.
So your 18AH battery becomes : 18 x 0.7 x 0.85 = 10.71 "usable" AH. Going back to your joules that'd mean a usable capacity (for this application) of 12 x 10.71 x 3600 = 462,672J
So I guess if you measure the apparent power drawn by your load, multiply it by 3600 that'd give you joules, then you could divide the usable battery power in joules to give you the total runtime in seconds. However as said before, battery capacity varies as a function of discharge current so it won't be exact.
In terms of your request for a UPS to supply 300W (I'm assuming at least two hours runtime) for under £500 - very doubtful. Don't bother with second-hand as you've no idea how/how long its been used.
tl;dr you need to get an accurate figure for power consumption. If its more than 100W then things are likely to become expensive given the length of runtime you require. Edit - forgot, I tested mine last night and with a load of 150W I get 110 minutes on a deep discharge calibration. That's with two year old batteries.
*this is entirely dependent on how much money you spend on batteries, how old they are and how many times they have been discharged. Basically if you buy cheap then you're not getting deep cycle batteries (they have thicker lead plates amongst other things) and you may only have 50% usable capacity. "Leisure batteries" are unsuitable for UPS by the way as are automotive batteries of any sort.
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I wonder, as an alternative to a beefier power supply, it might be possible to replace the equipment with less hungry equivalents, that would allow the existing UPS to last longer?
A while ago I wanted a new ethernet switch. I chose a TP-Link that by chance claimed improved energy efficiency, though I didn't really believe it. But when tested using a watt-meter, it really was quite a big 'win'. It's a 'proper' rack mount switch, too. Sorry I don't have the figure to hand but I think I waffled on about it already in some other thread.
ISTR that the Billion Modem/Router was also significantly better than the Netgears that preceded it. Can't promise that though, or put numbers on it.
It would all depend on what current equipment Weaver is using, and how much it could be improved by carefully chosen replacements, but the budget of £500 might cover a fair bit of new kit. Downside would be of course, whilst your electric bill would go down, your house would be colder and/or your CH bill would go up to cover the deficit. Except in summer, when it would actually save you money. Assuming you actually get summers on Skye, that is?
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Edit - actually looking at the runtime chart for the UPS linked below shows it would run for 4hrs48mins @ 100W and 2hrs38mins @ 200W. If the average idle power draw was in fact 50W then you could expect 7hrs37mins.
I reckon that to have a runtime of 5 hours for a peak load of 200W it'd take one of these to be sure that you'd still get 5 hours in a couple of years time* :
http://www.apc.com/shop/gb/en/products/APC-Smart-UPS-3000VA-LCD-230V/P-SMT3000I
Fairly sure you can source them for about a grand or so inc VAT but haven't looked lately. Obviously way more than Weaver's budget.
Its the HP managed switch plus the WAP that are probably going to cause issues. Can't remember what a Firebrick pulls but its unlikely to be excessive given it only has to deal with 8Mbps on the WAN.
Until he measures the power consumption when its all running flat-out and idle then its all guesswork anyway :)
*given the number of powercuts per year in NW Scotland then I'd budget on new batteries every 3 years (decent ones)
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It's not obvious to me why a WAP should be particularly power hungry.
They're restricted to tx power of a fraction of a watt are they not, under European law or something? Even allowing for inefficiencies, surely a watt or two at the mains socket should suffice?
What am I missing?
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Fairly sure you can source them for about a grand or so inc VAT but haven't looked lately. Obviously way more than Weaver's budget.
A quick look shows there are a couple on ebay well below that, one new at £650 and another used at £600, might be more... I did look at getting one but would have to get the floor joists reinforced so stayed with a 1500....
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It's not obvious to me why a WAP should be particularly power hungry.
They're restricted to tx power of a fraction of a watt are they not, under European law or something? Even allowing for inefficiencies, surely a watt or two at the mains socket should suffice?
What am I missing?
What you're missing is that his is dual-band and operating at 802.11n and 802.11ac speeds over two bands concurrently requires a non-trivial amount of signal processing. In addition the WAP doesn't sit there in "sleep" mode when nothing much is going on unlike a wireless client so its a constant drain even when there's bugger all going on network-wise.
I'd budget somewhere between 20-40W for the WAP but its all speculation really, best to measure it.
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Fairly sure you can source them for about a grand or so inc VAT but haven't looked lately. Obviously way more than Weaver's budget.
A quick look shows there are a couple on ebay well below that, one new at £650 and another used at £600, might be more... I did look at getting one but would have to get the floor joists reinforced so stayed with a 1500....
Aye the shipping is going to cost as its 52.5kg so H&S-wise its a two-man lift.
Edit - no its not, shipping weight is nearly 64kg which is over the two-man lift limit (60kg IIRC). Big batteries :D
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I'd like to thank Rizla for his generous post and extremely help Paul (cut-out-'n-keep) guide to battery calculations. There as a lot I didn't know there, the info with figures about efficiency particularly comes to mind.
I need to make some actual measurements, discuss with my FD how long a runtime we want and how much cash we want to spend.
I do know that the firebrick FB 2x00 is especially designed to be low-powered. Uses an ARM I think.
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Edit - no its not, shipping weight is nearly 64kg which is over the two-man lift limit (60kg IIRC). Big batteries :D
Even apart from Weaver's mobility issues, my own individual limit is strictly 25kg, wimp that I am. I know that because it's the weight of the bags of salt for my water softener. I can just about manage, but wouldn't be the first time I'd been visiting my Osteopath a few days later to have my back sorted. :D
Apols, off topic, I don't think Weaver's the type to mind. :)
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No idea what this company is like but a quick Google search found it here for £890
http://www.criticalpowersupplies.co.uk/smt3000i?gclid=CjwKEAiA3aW2BRCD_cOo5oCFuUMSJADiIMIL_hoZ3fvrm7D0txv2MihfmDp7MMgXvQzABNg3kqv_iRoCx7rw_wcB
To make it easier to move you could remove the batteries, there's two and they weigh about 12kg each.
http://www.apc.com/shop/gb/en/products/APC-Replacement-Battery-Cartridge-55/P-RBC55
Actually further investigation shows thats two packs of two batteries, so probably exactly the same ax what's in the 1500 version, but just twice ax many batteries.
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I can make it to the bathroom, luckily, but most of the time I'm bed bound because of the pain and drunknenness and confusion caused by all the simultaneous pain killers. It's difficult to explain if you've never been there. How much I can do depends on how well I am doing that particular day, and that is governed by how much sleep I have managed to get, and by posture. Whether or not I can install a UPS more depends on whether I can make it to the office without falling over and most important of all on whether I am too confused (drunk) to work out how to plug it in. Try making a cup of tea after you've had ten pints, that's the idea, the real essence of it. You don't need to hear all of this.
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Weaver, the more you tell yourself you cant do something the less likely you will be able to do it. You want a UPS so you will have to find a way to get it installed, now that may well mean enlisting the help of someone you know, which will probably still involve taking the batteries out of the UPS to make it easier to move if it's as big as the APC Smart 3000.
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@ronski - I'll find some muscle from somewhere, that won't be a problem. I was just explaining the reality of my daily situation as best I can, as you can't expect others to be psychic. ;D but it just isn't possible to try and "fight" the various neuro drugs I'm on, any more than it's possible to try and re-wire a three pin plug after you've had ten pints. I just thought it might make it easier for people if they had some understanding. Burakkucat has been very very helpful in doing jobs for me, for example. And I have some local friends who are gems.
Best
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I remember your illness from previous posts although others may of course not be aware, hence my suggestion about taking the batteries out so as to try and make it easier, but whilst it makes it lighter, it does of course involve fiddly things.
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I just run a calibration test on my APC Smart 1500 UPS, it started at 09:33 and completed at 11:13. I'm not sure at what battery level it stops the calibration test (looking at the logs it was at 24% at 11:17) but it lasted almost 1.75 hours, load was 0.6amps which is 144w which is about right for what I have on. So it seems my 5 year old batteries are still in pretty good condition - I purchased it on the 28 Feb 2011
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What does the battery condition/ rundown time depend on?
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I'm not sure at what battery level it stops the calibration test
20%.
If you discharge the (lead-acid) batteries further than that you run the risk of permanent damage, especially if it happens more than once or twice a year.
Ideally you never want to be below 40% charge as that will help maintain the lifespan of the (lead-acid) battery.
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What does the battery condition/ rundown time depend on?
I don't understand the question - genuinely. Didn't we go throught this a few posts back regarding load, charge & runtime? :)
https://en.wikipedia.org/wiki/Lead-acid_battery#Applications is probably a decent place to start for lead-acid batteries.
They have a finite lifespan which is pretty much proportional to how deeply you discharge them, how often you do that and what the peak current you draw is. Temperature plays a part but can probably be ignored for 99% of the time in the UK for internal applications. External applications will have an adverse effect in certain areas - eg a car battery in Aviemore won't last as long as one in Leicester if the usage is the same.
Basically if you put more load on them more often and charge/discharge them more frequently then they don't last as long. There is no hard & fast rule as to how long they'll last - it depends entirely on the application/usage.
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No, sorry, misunderstanding. I meant lifespan over the years which you've answered ;D
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Ah OK I thought I was losing the plot again :D
Edit - the nice thing about lead-acid batteries is that, unlike other batteries, pretty much everything is recycled into a new battery at end of life. I think its something like 98% of all materials are recovered and reused in a new lead-acid battery.
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The reason I suggested leisure batteries is that they are designed for deep discharge cycles and should last longer.
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The reason I suggested leisure batteries is that they are designed for deep discharge cycles and should last longer.
They're not jelv - they're like half-way between auto and UPS batteries in peak current/deep-discharge characteristics which is why they're in motorhomes/caravans.
They're a decent compromise but they're not going to be capable of what Weaver thinks he needs in terms of winter power cuts. I'm not convinced he needs the power he thinks he does but we'll maybe see as the thread goes on :)
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> I'm not convinced he needs the power he thinks he does but we'll maybe see as the thread goes on
I don't have an opinion on power, I just made up some number which I really hoped would be an overestimate, but I'm completely in the dark and am open to suggestions.