New system install. Advice please.

[Friday]

4 minutes ago, plonkster said:

TBH... I'm still a little shocked that someone is downgrading from a Microcare to an Axpert... (insert mental picture of me running away from torch-and-pitchfork wielding Axpert owners).

Its an upgrade for us - the Microcare is only 1 Kw and the Axpert is 5Kw and within our dwindling budget. Also Microcare can fly a kite as far as after sales service goes - I have had a problem on both the controller and the inverter in the 18 months we have used them and I got sweet fanny adams from Microcare when I approached them for help - they refused to even talk to me as I wasn't an "approved intaller or distributer of their products". I had to sort out the issues myself, which I did manage to do. They will not see a cent of my money again and if anything goes seriously wrong, the stuff will become expensive sinkers for fishing.

[___]

16 minutes ago, Friday said:

Also Microcare can fly a kite as far as after sales service goes

Yeah, I was really just kidding. My own experience with them wasn't stellar either, but I heard such good things from others that I assumed my experience must have been an exception.

I sent a working 40A charge controller to them some years ago to have the microcontroller replaced (well known issue on the older models) and it came back with the MOSFET driver stage blown. Must have happened in testing, or something. They asked me to send it back again, but since I was already seriously considering upgrading to more blue kit, and since it would have meant another two courier fees, I chucked it in a box and bought a new Vicky. I later disassembled it, initially disliked what I saw, then grew to like the simplicity. It's actually not a bad design, perhaps a bit old (async buck converter, most new ones are sync now), but definitely not bad.

I'm still not quite sure what is wrong with it. I repaired the driver stage and it works for power levels under 200W, but the controller reboots if you go above that. My plan is to rip out the controller guts, keep just the high-power stuff in the back, and put my own controller on it. Nice little hobbyist project... if I can ever find time for it.

[Friday]

46 minutes ago, plonkster said:

... They asked me to send it back again, ...

Yes, that was their only response to me - I could not afford to be without power for 3 months (their stated time it would take to repair). SO a woman with a screwdriver is a dangerous thing, eh.... I just took the covers off, oh the blasphemy!! I started at the first thing I could think of and replaced the inverter fan, which luckily sorted the problem LOL. then the same with the controller - process of elilmination starting with the simplest first and I replaced an isolator switch and there you go, it worked. So instead of talking to me they wanted me without power for 3 months and pay courier fees... go figure.

[Friday]

I think I am making some headway with the two system set-up.....

[___]

2 hours ago, Friday said:

process of elilmination starting with the simplest first

I wasn't that lucky. Well, in some ways I was, I watched Julian Ilett's videos on MPPTs, and that introduced me to the concept of driving N-channel MOSFETs on "the high side", as well as the generic buck converter setup (FET, Schottky diode, inductor), so when I screwed it open and saw the three big components on the back of the heatsink I almost felt at home. So what you do is look up the numbers of the various parts, and when I found the opto-isolator I knew what was going on. I got so much confidence in the process that I ended up buying an oscilloscope a few weeks later :-)

[Guest]

7 hours ago, Friday said:

14 to 17 years at 80% DoD

Not quite. +-4000 hours at 20% DOD - SOC of 80% = about 10 years.

Or 1600 cycles at 50% DOD.

Interestingly, if you keep them at 20% DOD or run them every day to 50% DOD, you should get the same AH out of the batteries.

So either oversize to keep above 20% DOD and pay more for the bank but keep for +-10 years.

Or ...

Spec the loads right, manage them as you do, and don't worry to go to 50% if you have to on said smaller bank knowing that every +-1600 cycle (+-4-5 years) you get to buy a new bank, for on my calcs, the L16RE-B's are at R2.75 per kWh.

If you want to be really the envy of this crowd, bar the litium groupies, IND33-2v are 1849ah at R1.52kWh ... but a 48v bank will kill the budget ... but you get 2800 cycles at 50% DOD.

My point, as you use the batts, next time you get better ones.

[Friday]

7 hours ago, plonkster said:

I wasn't that lucky. Well, in some ways I was, I watched Julian Ilett's videos on MPPTs, and that introduced me to the concept of driving N-channel MOSFETs on "the high side", as well as the generic buck converter setup (FET, Schottky diode, inductor), so when I screwed it open and saw the three big components on the back of the heatsink I almost felt at home. So what you do is look up the numbers of the various parts, and when I found the opto-isolator I knew what was going on. I got so much confidence in the process that I ended up buying an oscilloscope a few weeks later :-)

errr... that went so far over my head I didn't even see the contrail....

[Friday]

4 hours ago, The Terrible Triplett said:

Not quite. +-4000 hours at 20% DOD - SOC of 80% = about 10 years.

Yes, sorry my mistake

...

So either oversize to keep above 20% DOD and pay more for the bank but keep for +-10 years.

This is what our plan is. I can't afford to replace batteries every 4 or 5 years. Our current battery bank is sized to very very rarely go under 20% DoD, and with the new set giving us twice as much battery power as the current set it should, barring a catastrophe, last the full +- 10 years.

Spec the loads right, manage them as you do, ...

Oh we do, we started on the lifestyle change before we even went full off grid. At night, nothing stays on standby at all, our lights are only on where we are, our freezer gets turned off if we don't end a day with full batteries, security lights will all be timed and on motion sensors and with their own power/batteries, all phone, tool, laptop charging etc gets done daytime, and of course the constant draw from inverter and controller - basically our overnight needs are minimal and only the evening entertainment needs to be kept in mind and with only two laptops getting used it is also not heavy. All our heavy use gets done daytime. We have ditched a truckload of the convenience appliances and quite honestly don't miss them.

If you want to be really the envy of this crowd, bar the litium groupies, IND33-2v are 1849ah at R1.52kWh ... but a 48v bank will kill the budget ... but you get 2800 cycles at 50% DOD.

Which bank would you suggest? I hate ABSA so maybe them?

My point, as you use the batts, next time you get better ones.

Which hopefully will be in more than 8 years time for our older batteries and 10 years for our new ones - and who knows what the technology will have achieved by then

Also I think I may have won the two system battle!!!

 

[Guest]

9 hours ago, Friday said:

Also I think I may have won the two system battle!!!

HADMD (Hoe Anders Doen Mens Dit.) 

 

A thought to ponder for the future. You said, and I agree, few of us actually can: I can't afford to replace batteries every 4 or 5 years.

Once the current BATTERY (not ABSA) bank/s are done and dusted, do the sums for:
1) a bank that you use to 50% DOD - lean and mean and keep it going for as long as you can.
2) a bank to keep it at 20% DOD - there is a thought that a bank's chemical reactions will only last X years, whether you use them or not.
And, there is a case to be made to use more of the bank to get a better ROI versus nurturing it and losing a number of AH at the end in any event.

Right, here is the curve ball.
On option 1, the monies you have not spent, run the bank lean and mean and "save" for the next bank by investing the difference between option 1 and 2, thereby offsetting the replacement cost of the next bank in +-5 years. The longer you stretch the lean and mean bank, the bigger the investment payout.

Obviously it relies on financial discipline to save the monies, not spend it on other stuff.

[Guest]

10 hours ago, Friday said:

Which bank would you suggest?

If I was off-grid, I would seriously have looked at Trojan IND33-2v 1849ah at R1.52 per kWh. 6 of them for I would not have had a 48v system.

The guys here argue against 12/24v but here is where I get stuck on. I would have made my system fit a 12v system comfortably, for the =<500w load range is where the monies go ito battery banks.

And a 1600VA / max 2000va inverter to ensure I run at 1/4 of the inverters power to ensure it last as long as it can for I do not care for peaks on such a system. Want coffee at night, use gas. Want to heat the geyser, use gas if the EV tubes did not do the job that day. Want to run the microwave ... well tough. Use the gas oven.

I want to save on batteries yet have the comforts of lights, TV, tablets, Internet, stuff that uses power at night.

Daytime the game changes. Now we want to use said microwave, washing machine etc. For that I would have chased a 2nd hand picked up for next to nothing cheap like a Axpert 5kva 48v inverter with a small as can be throwaway when done bank to run the bigger loads on solar only, if there is solar.

For me it is all about saving the cost on said battery bank to last as long as it can if I am off-grid.

Off-grid or to save some real money versus Eskom, needs substantial lifestyle changes. Any off-gridder I have seen in places like say Alaska, run their systems lean and mean and their banks last 15 years. What they do make sense. Here in SA we have a lot more sun, so daytime is where you go bos.

So, for me to have 1 inverter and a 48v bank to make sure all runs 24/7 makes no sense at all seeing, as I said, the bliksim loads are =<500w. That is 12v level.

[___]

3 hours ago, The Terrible Triplett said:

The guys here argue against 12/24v but here is where I get stuck on. I would have made my system fit a 12v system comfortably, for the =<500w load range is where the monies go ito battery banks.

I think the only reason to go 12V is because you want something small that can run from your car battery (or the second battery in the back) when you go camping. Or perhaps because you're American and from 12V to 110V doesn't seem so steep to you. I honestly don't know why anyone would do it for a home system.

Why pick 1850Ah * 12V = 22kwh (at 14k a piece, or 84k) in this shape rather than 8 x L16RE-b, 48 * 370Ah = 17kwh (at 5.5k a piece or 44k)? Sure, the IND33 has about a thousand more cycles and has double the lifetime otherwise (17 years vs 8)? By my calculations (nowhere near yours), There is about a 20c/kwh difference between the two.

It still seems to me that you can compensate for the higher voltage by buying smaller batteries, that in terms of cost/kwh it all evens out. There are only three reasons to go smaller, the first is because your loads are (with only rare exceptions if any) small enough and you can literally get away with making everything smaller (which is not the case with those huge IND33s), because you have a different plan where you specifically pick the ability to extend over full independence (which is why I have a 24V system -- I drank the self-consumption cool-aid), or because you want lower quiescent draw (because it is a fact that a 48V inverter has a higher no-load draw, for the Multi it's 35W on the 48V, 18W on the 24V, and I assume less still for the 12V model).

If you need to save money on the batteries, buy smaller capacity batteries. As I said a previous time, that does have some limitations. Finding decent batteries below 100Ah isn't always easy and 4 decent 100Ah batteries will set you back close to 8k. I completely understand that perhaps 8k is a bit much for your budget, and this is precisely where I was in 2013, fixed budget of 25k and I had my heart set on a Multiplus which was 12k back then... :-)

[Guest]

1 hour ago, plonkster said:

There is about a 20c/kwh difference between the two.

I see L16RE-B 6v have gone up, IND33's prices dropped. More like R1.23 difference
T10RE's are now at +-R2.57 kWh - due to a recent price increase.
And the new 12v J200RE's are at like +-R2.70 kWh - less batts to connect though.

I am not saying get IND33-2v, you need to want the power and all that. But if R kWh is important to you, IND33-2v today are the cheapest. Just so you know.

 

First: I concede anyone wanting to run a house that 48v is better.

1 hour ago, plonkster said:

... first is because your loads are (with only rare exceptions if any) small enough ...

But as I say over and over =<500w per hour yes, those are small loads. Because one is off-grid, from 6pm to 12am I guess it will hover at 500w ph, and from 12am-6am more like 100w or less. Add to that a lower wattage loss because of smaller inverter where the standby load draw is even less, it becomes quite a low load.

Why such big batts you ask? If you have wants they may be more affordable long term.

[Friday]

I aplogise for my absence fro this thread - a rather nasty fire went through the Knysna Plett area last week and my focus was elsewhere. We are just thankful to still have our home and farm untouched when there is such devastation around us.

The decision was made to have two separate systems. so all the hardware I have is now sorted into these two systems.

I can't change the batteries as they are already purchased.

I now have a different problem. Is there anyone here that has already installed their system themselves, or knows how to wire the system properly, someone who is in the Knysna Plett area who could kindly either come and give advice onsite or that can talk to us real time on the phone. I know what needs to be done, but my husband needs to hear the technical stuff from someone else. Please.

If anyone can help me with regards to switches and fuses. Please.

[___]

There is a guest house up there somewhere in Knysna or neighbouring towns -- the owner sometimes posts/replies on Victron posts on Facebook -- but I cannot for the life of me find it now. I recall that the guy is dutch... can't be that many Dutch-speaking guest-house owners there. Unfortunately I don't know anybody else up that way. Yes I did my system DIY but I made a lot of mistakes and things I fixed later and even now there's still some labeling missing.

[SilverNodashi]

On 6/18/2017 at 0:00 PM, Friday said:

I aplogise for my absence fro this thread - a rather nasty fire went through the Knysna Plett area last week and my focus was elsewhere. We are just thankful to still have our home and farm untouched when there is such devastation around us.

The decision was made to have two separate systems. so all the hardware I have is now sorted into these two systems.

I can't change the batteries as they are already purchased.

I now have a different problem. Is there anyone here that has already installed their system themselves, or knows how to wire the system properly, someone who is in the Knysna Plett area who could kindly either come and give advice onsite or that can talk to us real time on the phone. I know what needs to be done, but my husband needs to hear the technical stuff from someone else. Please.

If anyone can help me with regards to switches and fuses. Please.

It's very sad what happend in Knysna last week! Glad to hear that you're OK though. 

Most people on this forum have done their own installations. Perhaps, state what you struggle to understand, or search the forums - chances are your problem has already been discussed before.