Solarexploits

Cable, 100m & 4mm normal solar cable

Morning Gents, as per title, where are people buying from? I've not found anyone cheaper than CEF for cable, anyone else found anything cheaper & still decent quality Tradesparky seems very competitive on inverters, tho' their after sales, supply times etc. seem a bit iffy, looking at past reviews. they are also pretty competitive on poanels, JA solar are coming out at decent prices, but they do have a £125 delivery charge on anything under 50 panels, which makes it a bit less inviting. ABsolar seem very good on bulk orders & large panels. I'm looking for "besy bang for the buck" basically, rather than necessarily most efficient panel for size etc. Who have you found is godd for what? Thanks in advance for any info

@ConorDo you by any chance have a copy of the general instructions you could post? Not bothered about inverter instructions as obviously will come with whatever inverter he chooses,& he's intending to do his own panel mounts on a flat roof, it's more stuff like where AC & DC isolators should be located, labelling such as you've described above that sort of thing?

I have plenty of idea re the install, I've already installed my own off grid system & have an MCS array fitted 11 years ago. But I'm well aware that electrical regs change frequently & don't want to assist a friend installing something which is then knocked back by a sparky because it doesn't conform to latest guidelines. He's looked at buying a complete DIY kit, but can pick up the individual bits far cheaper elsewhere

Read the OP - he's not looking for an MCS system, he's intending to DIY,not concerned with selling back to the grid, for the extra cost of installation of MCS, you'd need to be selling LOADS back to the grid for about the next 20 years to justify the costs!

Surely the installation doesn't need to be done by them, simply a question of having a sparky sign it off surely?

Hope this hasn't been covered b4, but couldn't find it anywhere with search. I know some of the solar suppliers that offer DIY install packages issue a complete set of instructions which I thought would be handy, both as a "shopping list" & for guidance on exactly where to fit breakers/fuses/AC cut off etc. Just wondered if anyone that's purchased one of these packages had a copy of the installation guidance, I've had a look around the web & can't find anything that's more than a basic list of "install the panels, install this, that & the other & connect to grid", I'm looking for something a bit more informative than that to help a friend with a 3.6kW DIY g98 install, he's not bothered about getting paid for any return to the grid so doesn't need MCS Thanks for any help in advance

It's a Powland 4/5k, I'm told it's a Voltronic clone. I've had some replies on the diysolar.com forum which are suggesting bulk charge at 57.6 & float at 54.9/55, I thought I might go slightly under those voltages for safety's sake I now understand your point re the freshening charge, would it make sense to reduce the max amps setting to 20A which would be pretty close to their suggested 19A & should therefore prevent any damage

"What charger do you have and what are its capabilities ? " The charger is the inverter, so it's either charging from the PV array or, overnight for 4 hours, it's charging from the built in charger within the inverter, in both cases the only control I have is the voltage setting on the inverter, which it would appear is definitely set too low, as you're saying that 2.29Vpc would be OK as a charge voltage, (tho' wouldn't give a full charge) which equates to 55V across the 4,they are currently only getting 54V. There is also a current limit setting whivh I think I have at 30A max for both charge systems, I would have expected that to be fine with 170Ah of batteries, would get a 50% charge in around 3 hours I'm slightly mystified that it gives 2.4Vpc for both "freshening" & fast charge, but you're saying that would be too high? In my ignorance I'm thinking that I'm simply giving them a fast charge if I up the voltage2.4Vpc I must admit I got somewhat lost by the whole thing about measuring amps taken & recharging to 103% etc - unless you had a dedicated charger that you could both measure what's taken (or Watts taken!) & had complete control over what the charger puts in, that just doesn't seem a realistic proposition in the real world If I get several years of battery life I'd be happy with that as they would have easily paid for themselves & I would hope to replace with Li in a few years time, I'm not worried if I shorten battery life by, say, a year, what I don't want to do is either undercharge so they keep dropping below 50% (or I have to remove some load), or overcharge so I cook them, which in both cases would presumably shorten life significantly more! It would appear the batteries aren't ideal for charging from solar, but I did get them very cheaply, if I went for a voltage between the 2.29 & 2.4Vpc, say, 2.35, so 56.4V across the pack, is that going to get significantly more charge into them without being likely to do significant damage?

The batteries are 170Ah, if you look at the range nomenclature for Powersafe, a 190 is 190Ah etc I realise now, that a lot of the info is actually within the data sheet, including the resilience to deep discharge, I just wasn't understanding it fullyPowersafe Datasheet.pdfPowersafe Datasheet.pdfPowersafe Datasheet.pdf I think all I really need to be sure on now, is , am I reading the datasheet correctly, see attached below, am I correct that the charge voltage can safely be set to 57.6V (2.4Vpc) without overcharging?

"I use Wh counting and it is very revealing, even though I know I may be almost 1Wh out at any time." How is Wh counting done?

Thanks for that, I've put a post on there

I know from earlier testing the batteries have differing internal resistance, (are any 2 batteries actually identical???) hence the battery balancers, which usually keep things within 0.1V of each other, but surely you would still expect that if you add the individual battery voltages checked with multi meter (confirmed with separate meter) they would come to the same figure (perhaps within 0.1 or so) of what the inverter is recording 2.29Vpc would give an overall charge voltage of 55V, the inverter is currently set on it's standard AGM setting which is 54V, so would it be worth changing this to 55V as otherwise presumably I'm not actually getting a full charge in? Actually, having just reread the datasheet it says both freshening charge & fast charge should be 2.29 - 2.4Vpc, so does that mean in fact I should have the charging voltage set to 57.6? If that's the case then I'm not charging them fully in the first place. I obviously want to get a full charge in whenever available, but certainly don't want to "cook" them! I do measure load, but have no way of tracking total load taken, the load is inconsistent as freezer cuts in/out, TV, lights or computer switched on/off etc etc - I always wonder how folks manage to come up with any accyrate figure for their "base load" as mine is certainly far from consistent even overnight as freezer would still be intermittent

Had a good hunt round the forum as I thought this must have been covered b4, but if it has I didn't find it. There are a no. of charts around t'internet showing battery voltage as giving a good guide to state of charge of the batteries, but there appears to be some discrepancy/alternative figures when it comes to AGM & Gel batteries I have 4 x Powersafe 12V 170FS deep discharge batteries, which are described by Powersafe as valve regulated Lead acid - elsewhere in their literature they refer to them as AGM, looking at the charts at 50% discharge, which I would prefer to stay above, for sealed or flooded it gives 12.2V & AGM at 12.3V. The batteries have got battery balancers on them & are normally within .1 of a volt difference, possibly a spread of maybe 0.15 between highest & lowest Several questions I hope you guys can help with as can't find it given anywhere in Powersafe's spec 1. Is that discrepancy of 0.1V reasonably accurate, might seem a little petty, but given that a drop of just 0.2V takes them from being 50% to being 25%, that's quite significant 2. Whether you measure with a multimeter at each battery, or take the reading from the inverter input, unless all loads have been removed (which would include the inverter, so you wouldn't be reading anything from that!) then the voltage you record is going to be under load, rather than the unloaded volts given in the charts - how significant is this likely to be, my load when no solar charge available is typically around 3 to 5% according to the inverter? - no idea how accurate that figure is, nor where it calculates it from or how. There does seem to be a slight discrepancy between what the inverter displays & measuring with a multi meter, for instance inverter displays 54.0V (it has increments of 0.1V), individual battery readings are 13.35, 13.38. 13.43 & 13.46, so I would expect a reading of 53.6V at the inverter? 3. As soon as the batteries are no longer being charged with solar, the battery voltage seems to drop quite quickly into the 49 to 49.9V level, load would be around 300 - 400Watts at this period, over the next couple of hours load rises to around 600 - 700W for a couple of hours b4 dropping back to around 200 Watts, by this point, currently around 4 hours after the sun's gone down, battery voltage is down in the 48 - 48.9V area, If I'm wanting individual battery voltage of 12.2V as a min, this is marginal, if it should be 12.3, then it's already too low & even with just 200W, a 4A draw, by the time the charger kicks in, another 2 & 1/2 hours later, will have dropped further - I'm not around to monitor this as already asleep by that point! Am I letting battery voltage drop too low, bearing in mind these are "on load" volts? 4.Having been charged on the overnight cheap leccy for 4 hours, by around 7am, still drawing around 200W at this point, there is already some (very small) incoming solar & voltage is up to 49.5 - 50.5 range - does that sound sensible? 5. How resilient are deep discharge batteries to dropping below that 50% & are the voltages you see in the common charts accurate for this type of battery, or are they taken from typical car battery sizes & what I'm looking at I should expect to be different? These were SH batteries, but are dated 2021, I started using them earlier this year & unfortunately as I didn't understand balancing & had some other hiccups, I did have one or 2 of them down at below 11V a couple of times, when they arrived with me they were showing 13.0V off load, I'm wondering if I've done some damage, but the pack as a whole has worked so much better since having the balancers on. From the charts anything below 11.8V is completely discharged, however, as I accidentally discovered, this is most certainly not the actual case as i defo measured at least one unit below 11.0V & others not far above & inverter was still working fine & supplying power as normal, it's safety cut off voltage is far lower at 42V or 10.5V per battery??? Sorry for all the Q's, hoping someone can help!

Just a thought, would it not be cheaper to buy an off grid inverter & simply take part of the house off grid as a completely separate setup? This is what I've done using SH panels & batteries with a new inverter So far as I have been able to establish providing the circuits you take off grid are completely separate to your existing consumer unit etc. then there is no further application required, as, although generating, the generating side is not connected to the grid?