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diy solar

Is my set up safe?

Solarfun4jim

Solar seduced :-)
Joined
Sep 22, 2019
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Location
Sunny Scotland
Anyone care to comment on my proposed set up. Unsure about fuse sizing. Over sizing my SCC deliberately, but assume that has not significant detrimental effect on energy harvested? Would 600A 'welding cable be ok to use between the battery and inverter if kept less than 1 metre length? Thanks.

12v battery vers 3.png
 
You're aware that each kW drawn will be 83 Amps?
edit - ignore this - I thought you had a 100A fuse on the microwave circuit
 
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hope you've got another means of cooking yer porridge!
Why? A few minutes in a 700w microwave would be sufficient. I have a 560AH lifepo4 battery pack that can happily discharge 1C rating if necessary, so i'm not sure of the problem you are implying. Please elaborate?
 
Why? A few minutes in a 700w microwave would be sufficient. I have a 560AH lifepo4 battery pack that can happily discharge 1C rating if necessary, so i'm not sure of the problem you are implying. Please elaborate?
Simply your location - you're right though - a few mins is fine, but winter yield is just so miserable in the UK winter, and worse for Scotland. Substitute porridge for chicken broth!
 
The only problem I see is that the inverter for the microwave has no shut off if the battery is out of spec. Low Voltage on a cell etc.
 
Simply your location - you're right though - a few mins is fine, but winter yield is just so miserable in the UK winter, and worse for Scotland. Substitute porridge for chicken broth!
Set up is for a diy camper coach, which will only be used spring till autumn. Care to comment on my fuse sizes as i'm a bit unsure on this?
The only problem I see is that the inverter for the microwave has no shut off if the battery is out of spec. Low Voltage on a cell etc.
The microwave would only be used very sporadically and would always be disconnected between uses. My BMS would give an indication of battery capacity or highlight any problems with the cells hopefully....so a BMS disconnection of the main inverter would set off alarms and hence you would not switch on the microwave in these circumstances. I simply felt the microwave draw was a lot to ask of the main inverter, when other items were running in the background.
Appreciate your comments
 
What BMS are you planning to use?

I wonder if the second inverter for your microwave as necessary, the Victron is quite capable, and as you have already noted, Microwave usage is flexible and on demand and can be tailored to the situation. What other high power devices will you be running on your main inverter that the microwave could conflict with?
 
What BMS are you planning to use?

I wonder if the second inverter for your microwave as necessary, the Victron is quite capable, and as you have already noted, Microwave usage is flexible and on demand and can be tailored to the situation. What other high power devices will you be running on your main inverter that the microwave could conflict with?
Have purchased a chargery unit....to have the relays wired directly to the remote on/off switching on the units...no need for seperate relays or contactors at all. I like the fact you have control, without all those amps having to pass through the unit....so a great back up to the victron units doing the main controlling jobs.

I will also be powering a macerator(400w infrequent use), two water pumps, led lighting combined with extractor fans in toilet and kitchen area(if the light is on then it is extracting at the same time...important to me to keep moisture levels low), fridge(constant draw), 400w heater (sporadic), socket for charging purposes(phones primarily), but occasionally, may run a toastie maker or very small kettle as well. Yes it could probably be managed off the main inverter, but would be a lot of faffing about?

Something like this for the microwave....(makes fuller use of the potential C capacity of the battery pack.)
 
A 700W rated output microwave is going to consume closer to 1100W. They're grossly inefficient. On that modified, it might be loser to the 1500W max.

Modified vs. pure sine wave:


Why not a cheap box store microwave and the mutiplus? WAY better option.

Lastly, you're not over-sizing your MPPT. 740/12 = 62A.
 
A 700W rated output microwave is going to consume closer to 1100W. They're grossly inefficient. On that modified, it might be loser to the 1500W max.

Modified vs. pure sine wave:


Why not a cheap box store microwave and the mutiplus? WAY better option.

Lastly, you're not over-sizing your MPPT. 740/12 = 62A.
I might still do that....depending on final loads etc. Thanks.
 
Have purchased a chargery unit....to have the relays wired directly to the remote on/off switching on the units...no need for seperate relays or contactors at all. I like the fact you have control, without all those amps having to pass through the unit....so a great back up to the victron units doing the main controlling jobs.

I will also be powering a macerator(400w infrequent use), two water pumps, led lighting combined with extractor fans in toilet and kitchen area(if the light is on then it is extracting at the same time...important to me to keep moisture levels low), fridge(constant draw), 400w heater (sporadic), socket for charging purposes(phones primarily), but occasionally, may run a toastie maker or very small kettle as well. Yes it could probably be managed off the main inverter, but would be a lot of faffing about?

So long as you would be willing to not use the microwave, toaster, and kettle simultaneously, I suspect you could use any 1 of those devices with the rest of your loads at the same time. Particularly if your fridge and micro are efficient inverter style units. Though the water pumps are wildcards, what sort of pumps/power draw do you expect?

The victron multiplus 3k can handle 2400W continuous, 3000W for 30 minutes, 6000W for up to 2 minutes (surge rating, not meant for normal usage).
 
So long as you would be willing to not use the microwave, toaster, and kettle simultaneously, I suspect you could use any 1 of those devices with the rest of your loads at the same time. Particularly if your fridge and micro are efficient inverter style units. Though the water pumps are wildcards, what sort of pumps/power draw do you expect?

The victron multiplus 3k can handle 2400W continuous, 3000W for 30 minutes, 6000W for up to 2 minutes (surge rating, not meant for normal usage).
The more i read you folks input, the more i'm coming around to the idea of having a single higher amp socket off the distribution box, which can either have the microwave/heater/toaster/kettle plugged in. The water pumps are low wattage(22W) and only need operate when running fresh tap water or using a recirculating shower....so again sporadic use. It would also mean i keep the discharge rating lower at any given time as well....Thanks for the input.
Sometimes simply discussing these things with folks makes choices much clearer. :)
 
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The more i read you folks input, the more i'm coming around to the idea of having a single higher amp socket off the distribution box, which can either have the microwave/heater/toaster/kettle plugged in.
This sounds like a good idea!

The water pumps are low wattage(22W) and only need operate when running fresh tap water or using a recirculating shower....so again sporadic use. It would also mean i keep the discharge rating lower at any given time as well....Thanks for the input.
I'm curious to hear more about the recirculating shower if you don't mind sharing. I've been considering the pros and cons of this sort of system recently.

Sometimes simply discussing these things with folks makes choices much clearer. :)
I totally agree, which is why I love this forum and others like it!
 
Proper wire sizes are essential.
If you share we can vet.
 
I'm curious to hear more about the recirculating shower if you don't mind sharing. I've been considering the pros and cons of this sort of system recently.
Are you recirculating the actual water, or just the heat? Is it to save water or power?
 
This sounds like a good idea!


I'm curious to hear more about the recirculating shower if you don't mind sharing. I've been considering the pros and cons of this sort of system recently.


I totally agree, which is why I love this forum and others like it!
The recirculating shower is simply to use as little water as possible, but still have more the a two minute shower. The run off from the shower is passed through a basic canister sponge filter(each user has there own sponge & disinfected in milton between uses). A small pump simply pushes the water flow back through the shower head. If you start off with 0.6 litre of water boiled from microwave and you add it to 1 litre of cold water, you can then prime the whole system with approx 1.5 litre of 40 deg c (approx) shower spray. After a days hiking in the hills, a spray down and a rub with a sponge using nice warm water...is a luxury....lol. You can stay under the shower till the water turns too cold, or you can have a jug of warmer water in the shower to 'top up' the heat. Not perfect....but beats carrying gallons of water for showering.
 
Proper wire sizes are essential.
If you share we can vet.
Joey, if you could indicate the wire sizing for the inverter to battery (say 600mm length) i'd be grateful. I was thinking of using 600A welding cable, but wasn't sure of the continuous use rating? I dont expect to draw anywhere near that current, but i'd rather spend a bit extra on wiring than be unsure. Thanks
 
Are you recirculating the actual water, or just the heat? Is it to save water or power?
Recirculating shower refers to the water supply in my experience.

Conserving heat would be awesome too, since this is one of the ways in which many of the recirculating shower designs are inefficient.
 
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