1 hour ago, Denns said:

Will actually buy a Victron 75/15 charge controller

That Victron stuff is very good 👍

9 minutes ago, tony Lampard said:

Hi @TaliaB “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire

16 minutes ago, tony Lampard said:

Hi @TaliaB “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

―Albert Einstein

I don't know where your problem lies, perhaps imagination is lacking?

16 minutes ago, tony Lampard said:

Hi @TaliaB “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

―Albert Einstein

I don't know where your problem lies, perhaps imagination is lacking?

That’s a thoughtful quote and a good reminder that both imagination and knowledge have their place. In my experience as an electrician and solar installer, I’ve found that imagination drives innovation, but sound knowledge and experience are what keep systems safe, efficient, and compliant. I’m always happy to share what I’ve learned, and I appreciate the diversity of views here it’s what makes this forum valuable for everyone.

Edited November 3, 2025Nov 3 by TaliaB

1 hour ago, tony Lampard said:

@TaliaB simple, inexpensive, smart Demand Side Management (DSM) to optimize solar systems seem to be way overdue? The very concept of a default "charge batteries first" is a mind blower when DSM suggests resort to energy storage only after the other demands have been met. Fridges and freezers smart controlled as "cold batteries" is a no-brainer. "Increasing my battery capacity, need ideas" I answered with perhaps @Bran look to optimize what he has first using DSM you regarded with disdain as "off topic". Therein lies an opportunity for someone with "imagination" to develop, sell and install simple, inexpensive smart DSM systems perhaps?

Your idea is the same as a person who wants to run around collecting coins and fighting the teller over a 5% discount on a 100 rand purchase in the hope they can fix their financial situation, when sometimes more effective ways of changing jobs, starting a business, or studying further are better.

Setting your battery to charge only after the loads are met, etc, won't fix anything. Even if it is a more efficient way of doing things, and you save some 0.5kWh. That still won't do anything. Add more panels, replace power-hungry items with more efficient things (like a heatpump vs a geyser element), and add more batteries. These 3 methods are the best way. Not playing around with fridges, etc, using DSM, etc.

Just add more batteries or Panels or kill power-hungry items. That's it.

IMHO, both, the generation and consumption are two sides of the same equation.

• If the generation is extremely poor, there's no point in trying to optimize the loads.

• And vice-versa, if the load is too lavish and wasteful, it's better to optimize it, before spending more on additional panels and batteries.

Speaking of "charging the batteries first vs. supplying the loads" all the systems that I know work in a way that if the load is ON, then the energy flows to the load, bypassing the batteries completely. Batteris are being charged only with the energy that is left after the loads are satisfied. This applies even to low-voltage systems (12/24/48V), where chargers are connected to the battery bus and inverters are connected to that same bus too.

I see that the OP is aware that the energy has to be used reasonably and he's doing it already. Looking at his system, it's obvious that battery and PV upgrades are the next logical steps.

41 minutes ago, Youda said:

IMHO, both, the generation and consumption are two sides of the same equation.

• If the generation is extremely poor, there's no point in trying to optimize the loads.

• And vice-versa, if the load is too lavish and wasteful, it's better to optimize it, before spending more on additional panels and batteries.

Speaking of "charging the batteries first vs. supplying the loads" all the systems that I know work in a way that if the load is ON, then the energy flows to the load, bypassing the batteries completely. Batteris are being charged only with the energy that is left after the loads are satisfied. This applies even to low-voltage systems (12/24/48V), where chargers are connected to the battery bus and inverters are connected to that same bus too.

I see that the OP is aware that the energy has to be used reasonably and he's doing it already. Looking at his system, it's obvious that battery and PV upgrades are the next logical steps.

I understand how DSM can technically improve the current battery capacity one can have.

Supplying loads first and then charging batteries with whats left increases efficiency by some 10 to 15% if I was to guess. Running most of your loads during the day can help also. If you set your freezer very cold, you can run it only off PV and then at night the freezers can all be off. I do this with my outside fridge at the moment but the larger inside one is a new inverter fridge which uses next to nothing so that approach doesnt help.

I am not dismissing his proposal, I used it to reduce reliance on batteries at night and have been able to run off grid with GEL batteries for a while now without needing a generator etc. But the crux of the matter is, the OP needs battery/PV upgrades.

On 2025/10/18 at 12:56 PM, TaliaB said:

@Scorp007 If you have used them in parallel to the same cell count same chemistry lfp battery for 3 years without problems then maybe the Op can use a diffrent lfp battery in parallel. It would be much better $$$ wise to just add another 5kwh battery than 2 inverters with separate batteries.

Quite a late reply. Yes the same chemistry and cell count. Mecers, Hubble S-100 and DIY makes 3 sets that worked fine in parallel for a few years. Mecers were the string that provided the lowest current at any load. The S-100 with 2nd life cells had the lowest internal resistance and provided the most current. Also were bought new and thus the other 2 strings were years older and I was the 3rd owner. It worked for me when I used the Mecer 24V inverter. Hubbles and DIY still in use on my Deye 5 kW.

16 hours ago, tony Lampard said:

Smart appliances with human interface so that solar is optimized seems way overdue, especially given how rapidly solar adoption has grown. The technology pieces are all there: Smart plugs and IoT-enabled appliances exist; Solar inverters have APIs and monitoring systems; AI/ML for load prediction and optimization is mature; Smartphone interfaces are ubiquitous.

The trouble will be standards. If I have an LG washing machine and a Samsung deep freeze then will the smart features work in the same way, can they be incorporated into the same virtual environment? It may get like IT, where the joke used to be that the good thing about standards is that there's so many to choose from. The Internet changed that scenario in IT quite remarkably, but if it's left to manufacturers then they will all do their own thing.

So smart control built into wall sockets and DBs allowing us to control individual circuits is probably a more practical way. Even then there are still choices.

This is for turning things off and on. I do have an LG washing machine, and I can (but don't) connect it to wifi and program it, pause it, restart it etc. But this is done via an LG app, so probably proprietary. I would like to have my heat pump, the guest geyser, the pool pump all part of the same little ecosystem ruled over by yours truly and with some rules built into it so I can say (example already given) the guest geyser can run on a sunny day, or when other loads are low and the battery has > X SOC.

So we need some smart switching as well. Most days I can run my whole home on the 20A my inverter will output. So I would like a way to switch the non-backed up circuits to backed up if the grid goes down or if it's a lekker sunny day. I don't want a manual change over switch because I know I will forget to change it back. Manual override will be nice for the times when I know that I know better than all that smart stuff.

.

Edited November 5, 2025Nov 5 by Bobster.
Off topic. Too much of a digression. Deleted by author.

1 hour ago, Bobster. said:

The trouble will be standards. If I have an LG washing machine and a Samsung deep freeze then will the smart features work in the same way, can they be incorporated into the same virtual environment?

To some extent yes. One can interface with e.g. a smart LG product via the LG ThinQ integration, unfortunately this still runs via LG's cloud "service" rather than a local network. Similarly smart Sasmsung products can be controlled via SmartThing which also requires a Samsung account. It seems as if many commercial "smart" products are just honeypot traps designed to lock the user in a proprietary ecosystem.

Note that I do not have experience automating these proprietary smart devices, I use smart switches running opensource ESPHome or Tasmota firmware.

Maybe one day something like the Matter standard will put the power of home automation back in the hands of users.

11 hours ago, tony Lampard said:

@Denns Your response is bordering on argumentum ad hominem (a fallacy - flaw in reasoning) attacking my character as a diversion, demonstrating you do not optimize for our interests but rather try and maximize billable work. Perhaps you also need to do some more homework "with more efficient things (like a heatpump vs a geyser element)" - a geyser element is a resistive device irrespective of whether it is connected to DC or AC (DC is actually more efficient -AC "heating value" is lower expressed as RMS) it will dissipate energy in the form of heat. Something that's genuinely elegant in its simplicity for "more efficient things" is DC-direct soft loads bypass a lot of the complexity (and losses) of the AC conversion chain entirely.  The geyser element connected direct to solar panels producing variable DC voltage directly heating water is perfect. The resistance element doesn't care if it's getting 200W or 2000W - it just converts whatever's available to heat. No inverter losses, no MPPT complexity for that load, no control logic needed, no overload. Pure solar-to-thermal conversion with the panel voltage/current naturally self-regulating.

Nope. Not attacking your character at all. If you feel that way then that is on you. I just made an analogy.

No amount of load management will fix the problem of energy in >= energy used. You can have a 100 smart switches and you still will need to power them. You can use DC and improve the energy conversion efficiency from the current 90+% most AC inverters can do currently and you still won’t hit your energy needs if you can generate or store enough.

As for direct heating of the element with panels. What improvement in efficiency do you get? 10% if you are lucky. A HP will use some 3kwh to heat a 150 litre geyser from tap water cold to 70. Your panel’s will have to supply that 8/9kwh. Efficiency won’t help you there.

12 hours ago, tony Lampard said:

DC is actually more efficient -AC "heating value" is lower expressed as RMS) it will dissipate energy in the form of heat.

A geyser element is a resistive heater. It converts electrical power to heat via I²R losses, whether the current is AC or DC. On equal RMS current (or equal power), the thermal energy delivered is the same. The difference you were hinting at is electrical waveform but for a plain resistive element the outcome (heat produced) depends only on the instantaneous power, not whether the source is AC or DC.

12 hours ago, tony Lampard said:

Perhaps you also need to do some more homework "with more efficient things (like a heatpump vs a geyser element)" -

Heat pumps are not a direct replacement for resistive heating on the same basis they move heat and therefore have COP > 1 (commonly 2.5–4 in domestic conditions), so they deliver more heat per kWh of electrical energy than a resistive element. Even after inverter losses, a heat pump will usually provide markedly better kWh-to-heat efficiency than a directly-heated element. That’s why they’re often the most economical long-term option where electricity is available.

2 hours ago, tony Lampard said:

@Bobster. Wow, great to read Bobster - so refreshing to find a kindred spirit instead of all the can't do attitudes we have had in this discussion. Sure smart sockets is a start (doesn't give your the fridge freezer battery - lowest temperature when lots of solar, drift to highest acceptable at night) but we can get there - I have found the Theory Of Constraints (TOC) helps through these hurdles. I like the soft load for the geyser connected direct to solar panels (been there done that 4 x 450w panels to a kwikot 3kw element- works a treat) no DSM required. I haven't done the DC motors though but those will also be automatic DSM soft loads methinks; I hope the MV tech is leveraged in this area..... DC household solar systems sounds like a good idea. I would like to be able run my DSM from my cel phone even out the country "switch off grandma's tv if the solar is iffy". I was actually appointed unsolicited as a TE on the ISO global network so "sustainability" standards I am familiar with; I was arguing about commonality of spares for cars, "why can't common parts like brake pads, oil filters and shock absorbers be the same for a Toyota Hilux and Isuzu D-Max" - its the old greed over convenience problem "If I have an LG washing machine and a Samsung deep freeze" that constrains interoperability.

Thank you. There are large chunks of your reply I don't understand :-) I'm guessing DSM here is not Diagnostic and Statistical Manual.

5 minutes ago, Bobster. said:

Thank you. There are large chunks of your reply I don't understand :-) I'm guessing DSM here is not Diagnostic and Statistical Manual.

Demand side management. Its something a lot of us already do.

Edited November 5, 2025Nov 5 by Denns

1 hour ago, tony Lampard said:

Sorry, Demand Side Management (DSM) - its simply managing your demand balancing variable generation from solar.

I knew I'd end up kicking myself. I used to have a DSM levy on my electricity bill.

50 minutes ago, tony Lampard said:

"usually provide markedly better kWh-to-heat efficiency than a directly-heated element." .... "where electricity is available". Therein lies the argument against heat pumps with solar systems; if you have a 5kW solar system off grid switching on a 3kW heat pump, with all your other loads, its a DSM nightmare.

I have a heat pump. This morning it started at 6 (programmed) ran for 50 minutes, never consumed > 1.4 kW. OK... That's better than a geyser but it's still something. But how much PV do you think I was getting at 06:00?

It mostly consumed battery, about 12%.

The advantage is I don't need the sun to be shining to heat water.

The DSM comes in the evenings. I had 68% of a 10 kWh battery avaliable at 06:00. During a sunny day the midday run of that heatpump is essentially free.

The way I see these things, the heat pump scores on low peak power. My inverter has a 20A limit. If I ran a regular geyser at 6 I'd either get close to that limit or have to wait longer. As it is, that pump draws 6A.

It's always like this. Solar is a resource you have to manage. You rob Peter to feed Paul. This includes adjusting routines. Because I do DSM in the evenings (an advantage is full gas cooking) I get a hot shower in the morning, load shedding or not, 12 months of the year.