ClintonDBN

Thank you, I've been checking out a few online charts and calculators but ended up just confusing myself more 😂 I started wondering whether I need to add the amps from the two lights and pumps, and then confused myself with seriew vs parallel, then I got an idea of cable size and then got caught up on ripcord vs cabtyre vs surfix (??). Then I started concerning myself with earthing... Hoped someone might just say get this size and this is what it's called 😁 Edit: I see that chart also doesn't mention actual cable sizes. I presume there is a key missing?

I am running off grid. I have a separate panel, batteries and a charge controller that I want to run some 12v garden lighting and a small 12v garden pond fountain pump off. I am unsure of what cable to use between the batteries and the lights/pump. Lights - no more than 20w LEDs, probably 10w, two of them at most. Pump - 12v 12w pump. Distance - batteries to pond is about 20m one way. I have an inkling of an idea about voltage losses etc but am looking to do this the most cost effective, but obviously safe, way. What is the smallest cable size I can safely use? I will need to go across the garden so I will need to bury the cable. Will basic white 25mm conduit suffice or is there a better way?

Hi, Just wanting to bounce something of you guys and gals. I currently have solar set up with 4x250w panels, a 150/85 Victron MPPT, a Cotek 2000w 48V inverter and 8x 105ah 12v batteries connected in series/parallel to give 48v banks. My Cotek inverter has been giving me issues and this is where I've been thinking. A family member has a 24v inverter. I have also been looking online and there are some good reviews for a 24v Chinese inverter. Yes, yes, I know but budget is tight and I was thinking of having it as a back up to the family member's one. This is where my layman thinking needs some wise brains to bounce this off. I realise 48v system is better in most instances as it allows for smaller cable sizes. The charge controller can also be a lower amp one. The latter is not an issue with my small system as 85amps is fine. When it comes to cables, the battery bank, inverter (whichever it ends up being) and charge controller are all within 1m of one another. The only thing that is distance are the panels with cable length of under 10m. Would I need to increase my cable sizes if I decrease voltage? What potential issues do you see if I change my battery bank to 24v from 48v? My current daily power usage is under 4kw/h. I realise I may run into issue of I want to increase panels one day. True? I have read that too many parallel banks are not suggested. I'd be looking at 4 parallels of 2x 12v batteries then connected in series. Will my battery efficiency be affected? I already run to 40% DOD so don't want to be running the batteries lower if this is somehow effected? Thanks in advance.

Sorry, most of that was foreign to me 🙈 But my inverter isn't the greatest, it is a Cotek SK2000 48v.

Thanks. So my float is a little high at 55.2 so I'll reduce this. The issue is I can only see where to set absorption and float on the Victron connect app (as shown on the screenshot - together with equalisation which I've read mustn't be used on gel) but not bulk. You can also change max charge current but I see no bulk voltage setting.

That leaves me worried whether I should be concerned! 🤣 The very basic instructions that came with the batteries had me confused about what settings to use so I went with the Victron rotary switch option which included Victron gel. The settings looked about right based on my limited knowledge and a little Googling. Maybe someone can confirm or tell me exactly how wrong I am... 🙈 Attached are the settings on the Victron and the battery brochure.

Hi all, I understand that you cannot ascertain the state of charge of a battery by measuring voltage across the string as it'll be affected by load etc. But I have been keeping track of battery voltages shown on the Victron Connect app during the course of a day to get a general idea. Our place is tiny so more often than not the load will be similar as I'll know exactly what is on. I know there are tables online that equate voltage to SOC and there is much debate over this due to load, temperature at time of measurement etc. What I'm interested in here is the voltage that my Victron SmartSolar MPPT charge controller is showing during the course of a day. The thing of most interest is that maximum voltage of the 48v battery string during a day. Should I be concerned (or happy) about being told that the max battery voltage was over 57v? I know the voltage of fully charged battery will be higher than the given voltage but is as high as this "normal"? I was on float for over 4 hours today which I'm happy about. I'm trying not to go under 70% too often.

Thanks guys. And this?

What about this sort of thing (besides it being cheap and from China 😂), would that be able to give me an indication? I hear the talk re BMV but we talking R2000+ vs R200. Yes, I know I need to weigh that against replacing the batteries prematurely but I'll get there. Does one BMV monitor each 12v battery or only the whole string?

Thank you. Would it be fair to say then that a voltage of 50v under load would allow you to conclude that the actual voltage might (must?) actually be higher than this. With battery monitors like the attached is the point really to compare voltages to get an idea rather than an accurate measure? Or are they just a waste of time?

Hi guys/gals, I am needing advice please. I think I know the answer but I'd like to confirm. I have two strings of 4 x 12v 100ah batteries connected in series. These two strings are then connected in parallel. I have a Victron charge controller which shows battery voltage. This gives me an indication of the state of all the batteries as a 48v set up but I would like to be able to regularly check the state of charge of each 12v battery. Is this possible without disconnecting all the batteries and testing them individually (and if so, how)?

Can't say no to R10.90 a beer with 90c back in my neck of the woods. 🤣

Chickens are certainly in the plans. The one issue is having natural hunting dogs... 🤣

Thanks to this forum I've already been successfully assisted twice with my solar set up, so I thought it only polite that I introduce myself. We have a small, and I mean small (not sure how familiar everyone is with the "tiny house" and minimalist movements), place up in the Upper Highway area of KZN. The intention is to try and reduce our impact on the environment (and reduce costs!). We'll never eliminate the negative impact but we can try to reduce it. We are not connected to municipal services at all. Rain water is harvested and filtered for all our water needs. Power is provided by solar and supplemented by gas for hot water and cooking. Waste is dealt with via a septic tank. We are also getting a veggie garden going but we'll need to build an enclosure before we get fully into that (vervet monkeys!). We have also planted a number of fruit trees with more to come. In the garden we are looking to be very water wise so succulents and a bunch of spekboom. Anyway, that is us. Look forward to learning more from this forum. This last year has taught me plenty but there is a lot more to learn.

Thanks so much, guys! Section 15 it was. I had Googled and found all sorts of instructions on how to program the remote but not how to change the mode. I now have three working remote controlled LED lights!

Hi, Wasn't sure where to put this but I use it for lighting so thought this might work. I have three Centurion (Centsys) receivers with the nt72c-s10 relay (as pictured). I am connecting them via a 48v-24v DC-DC converter to my LED lighting. They were working fine but the wiring was a mess so in my infinite wisdom I thought I'd rewire. Two are working fine wired exactly as they are in the picture but the one clicks and lights up when the programmed remote button is pressed but then clicks straight off again. The light does come in during this brief on and off period. The ones the work click once when remote pressed and light stays on and then clicks again when remote pressed to turn light off. Any ideas why this one is not behaving like the others?

I'm only doing it this way as I already had the 48 to 24 DC-DC and the LEDs are all 12/24v. But I am a newbie so always open to advice.

That'd be a lot easier! I (based on my inexperience and using Prof Google) thought that might not be perfect balance but, in thinking about it, it would obviously still travel through all 8 x 12v (or in this case probably more accurately 2 x 48v) batteries.

Excellent, thanks. I was unable to post images I think as it was awaiting approval. I see the link now. Attached is the promised image. So just to confirm the 48v-24v DC-DC would be added to the "pile"* of connectors on the bottom left - ve and the top right +ve? * pile being parallel connection cable, cable to inverter and cable to charge controller - was already a squeeze so I hope I can get a fourth wire on.

Hi guys, Been using this forum for guidance on my system, so thanks for all the information shared. Today I expanded the existing 4 x 12v in series, 48v bank into two 4 x 12v strings connected in parallel to each other. All new 100ah batteries were used. From these I have connections to a Victron controller and a Cotek inverter. This is all good. My question relates to a 48v to 24v converter that was originally attached across the one 48v string of 4 batteries. This was used to run all the LED lighting in the place (a very small place so not a huge amount of lighting). How would I now connect this to my current set up of two 48v strings connected in parallel to ensure a balanced load on the batteries? Thanks in advance. As soon as I fathom how to load images on this forum I'll upload my very rough diagram 😊