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Thanks. I've had trouble finding appropriately sized DC-DC boot converters. Hence the question. Found one today with 12V 15A output from 5-11V in. I'll report the outcome when I get it. Next question: can I use two DC-DC boost converters in parallel to get 30A 12V output? Charging the 6V...

I'd like to find a DC to DC converter option to output 12V from a 6V battery - and charge it from a 12V charge controller too. The battery is 625AH and I can't find another similar battery to make it a 12V system. I'd like to draw out and charge with 12V ~10A. Anyone here know of any DC-DC...

No. The two MPPTs will chase each other's tails. Split your string into two strings of less than 5kW each

I wish to control an ATS (Automatic transfer switch) based on PV output and battery state of charge. Completely independent of mains voltage. My intention is to run the house on battery when there is insufficient PV output to cover my power demand - including at night, AND there is sufficient...

Does anyone know where I might find another 5 cells for my battery in Australia? These are wet vented nickel cadmium cells with 625AH. About the size of 2 large car batteries each cell and around 30kg .... I have 5 spare, but would need 10 to make a 12V system.

Many thanks, Syd! That's pseudocode that gives me a start - to at least ask the right questions and look for the right answers.

That relay looks like it didn't extinguish a switch-off arc! Are you certain it was meant for DC switching? They need a MUCH larger gap between contacts.

Would you please go into a bit more details - or even show the code? You have just outlined EXACTLY what I would like to do with our hot water tank, but I donlt really know how. I have some arduinos and some electrocnic skills - just not enough to pull this off by myself safely.

I learnt that if you cut yourself accidentally and then touch 12V with in the cut (with a bloody surface) it gives you a pretty nasty - unexpected- shock!

This is the meter I have: https://www.aliexpress.com/item/1005002381940978.html No, they are not a charge controller, they actually check the panel output directly. Do these tests with a clear sky and the panel facing the sun as close to perpendicular as you can.

Man that's a scary video! I'm fairly sure that non-isolateed inverters are illegal in Australia, but that doesn't mean they could fail internally to have a live connection on the DC circuit. I'll ground any future PV hardware and comply with the rules.

I'd say you have a perfectly serviceable setup there - bar the batteries of course. The unpredictable bit are the solar panels. A volt meter gives you just an indication of their open circuit voltage. What you really need is a cheap MPPT meter (look at Andy's Off-Grid Garage website - link in...

Been reading all I could here and in the regulations I have access to. Grounding/earthing of all PV collectors and their frames and mountings is now required here (it wasn't 15 years ago when I had my first grid-tied PV system installed). Can someone please explain the purpose of that? I...

I've just bought 30kWh Nickel Cadmium cells in terrific order. They've been kept charged and maiintained and seem perfectly good for another 20 years. I've just contacted the French/German manufacturers SAFT for a current value and maintenance instructions. I had some used open/vented/flooded...

Watt = Volts x Amps. So your 36v X 5.5A panels output 198W(maximum). If you put them in parallel as you indicated, e.g. for a 12V battery system, you need a charge controller with a capacity of 5.5A and a maximum of 36V (lets say 50V to be safe). If you were to put them in series, e.g. for a...

I think the point being missed is that mppt controllers put a load on the array to get the output voltage to the best power (V x A). Once the first mppt controller has done that, the second one woun't be able to and so can't work as an mppt. If it works for someone, then the second one has...

I have the same question, but am concerned about ANY BMS disconnect. It has happened to me twice now due to one cell being a bit too fast charging and it's voltage running away. The BMS just shut off. I wondered if I should precharge or just measure the inverter input voltage first. I realise...

Depends on what you are trying to achieve? If you want to donate your unused power to the grid, yep, a grid inverter (e.g. microinverter with current limiting circuitry on the 24V side) will do that. If you want to use the power yourself instead of paying for the grid, just go to your local...

OK. Problem solved I think: I reduced the solar charge voltage to 13.8V and fitted an active 5A battery balancer. The cells were within 50mV within a few hours so I reconnected the solar charger. So far so good. The battery seems to sit on 13.6V and all is well. No more imbalanced cells and no...

I just came across a great analogy: The long term effect of seat belt laws is that more than 98% of all fatalities among car drivers and passengers were wearing seatbelts. Think about it....

There should be no voltage leaks to the frame at all. Can be dangerous i there is, depending on the voltage of your array. When you finish the install, with the earth connection temporarily disconnected, check you roof (if metal roof) voltage against ground. Watch out for what you touch!

I've had the same issue with my generator. I decided to put in a change-over switch instead of blowing the inverter again. So when I need to use the generator, I flick the switch first. That disconnects the entire PV/Grid/Inverter input and connects the generator input socket. Then I start the...

I replaced the 240V element in my Dometic 17l water heater with a 300W 12V element. It runs off solar, battery or engine alternator. no problems at all and takes about 2-1/4 hr to heat from cold.

I don't think that is a good idea.... The fridge is a variable speed brushless DC compressor fridge. At least as efficient as an AC fridge. It uses 48W (4A) and I have 700W solar panels allowing around 23A draw on a sunny day in Victoria... I suspect many inverters use that much as operational...

I have reduced the charge control to 14.2V on the basis of the suggestions here. And yes, I am using a DC fridge.

I disconnected the battery for a few days and found that one of the cells is indeed over voltage. I did a lot of reading in the meantime and learnt that my Daly BMS actually doesn't balance the battery. It just monitors and protects. Well, it does actually passively balance at "up to 30mA" which...

A1: Yes, I can access the battery cells easily and measure their voltages with my multi meter regularly. So far I have not seen any voltage differences of more than a few 10th of volts. A2: Yes, I have a wireless shunt monitor connected all the time. It shows the voltage between battery...

That hits the nail on it's head! I'll check the SCC manual to see if that option is there. Mine looks like the 40A one here: https://www.ebay.com.au/itm/392824462054 I'll check the exact model tomorrow to confirm.

We have just returned from a 5 months' trip around far northern Australia in our Transit campervan. It came with a Dometic 240V electric hot water service of 17 litres. The element was 1.4kW and heated from cold in 1hr. Just before the trip, I replaced the element with a 12V 600W element as...

OK, so the specs for this "dumb" BMS are: 3.7V (x 4) overcharge disconnect, 3.6V (x4) charge reconnect - on paper. In reality, I think it disconnects at 3.65V and reconnects at 3.55V (x4). @smoothJoey: There are not normally any loads at all. When the fridge runs (4.8A) or the lights are on (1-...

Yep, battery voltage is 14.40V Dead on. The BMS hasn't "tripped", it just went to 0A in or out. Which effectively disconnects the battery from the ground.

Set to 14.4V - it's an auto sensing 12/24V MPPT charger. So it seems to ignore my setting when it can't "see" my battery. I have no idea what the settings of the DALY are. It is not a "Smart" BMS. I can't communicate with it. Factory settings, I guess.

This has happened only a few time, but is disconcerting: When my LiFePO4 battery is fully charged and no load on the system at all, the DALY (common terminal) BMS appears to disconnect the negative terminal of the battery from the vehicle negative/ground. As it probably should. However, the MPPT...