A few questions - switches, cable size, shore power, fuses...

[Kayte]

I have a T Tocas 50a circuit breaker which I believe goes between the PVs and CC. Do I also need a MIDI type fuse block/fuse? And if so, what size fuse? What size cable from either the fuse or switch to the CC? (24v system)
Does the shore power receptacle connect directly to the inverter (only inverter, not inverter/charger) or do I have to have an AC charger before the inverter?
What size cables should I use from the battery (24v system) to the inverter and converter (12v)? Before it gets to the inverter and converter, will it first connect at a bus bar and the cable size should be?
I'm starting out with one battery but may add another eventually. So what size cable between batteries?

 

[rodrick]

You need to list the info on the scc, converter and inverter, the manual for these items should tell you the amps that each will pull and you can size the wires accordingly, fuse wise look at a Anl or mega type fuse minimum a class t is even better this should be located as close to the battery as possible remember the fuses job is to protect the wires

 

[mikefitz]

Does the shore power receptacle connect directly to the inverter

No, not needed for an inverter.
See diagram for a basic systen. Over current protection at the battery and positive buss bar.
With a 24v lithium battery, fuse at battery needs to be class C or HRC
Any shore power charger connects via a fuse to the positive buss bar as does your 24 to 12 converter.

Fuse for the expected maximum current X 125 to 150 %, example if current is 100 amps, fuse at 125 amps.
Cables must be rated for the current,

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Mike

 

[Kayte]

No, not needed for an inverter.
See diagram for a basic systen. Over current protection at the battery and positive buss bar.
With a 24v lithium battery, fuse at battery needs to be class C or HRC
Any shore power charger connects via a fuse to the positive buss bar as does your 24 to 12 converter.
View attachment 167480
Fuse for the expected maximum current X 125 to 150 %, example if current is 100 amps, fuse at 125 amps.
Cables must be rated for the current,

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Mike

Okay, so I need a shore power charger since my inverter is just an inverter and not a combo inverter/charger.
Despite researching and more researching, I'm still in kindergarten. So I don't know what a class C or HRC is or Anl or mega type or t.
I have a Blue sea 5191 MRBF Terminal Mount Fuse Block 30-300 that goes directly on the batt terminal. I have two 250a maxibus busbars, 4 studs. I have a 100a current shunt with meter. I have a battery power cut master switch.

 

[mikefitz]

So I don't know what a class C or HRC is or Anl or mega type or t.
I have a Blue sea 5191 MRBF Terminal Mount Fuse Block 30-300 that goes directly on the batt terminal. I

This link in Resources may help with fuses,

DC Fuse and breaker Sizing and Placement

To get the paper, click on the orange button at the top of the page. The attached presentation gives the fundamentals for picking fuse/breaker sizes and describes where in the circuit they should be placed. You can download the presentation...

diysolarforum.com

Midi and mega fuses are OK after the buss bar but the 'master' fuse at the battery needs special selection.
If the battery is lead acid then MRBF fuse is acceptable, however at 24 volts, for a lithium battery, a higher specified fuse is recomended.

Fuses have a maximum current interrupt rating. Depending on the energy source there is a possibility a very high current could flow through the fuse. Although the fuse element would fail there is a possibility the energy would 'jump the gap', thus damaging the circuits the fuse was intended to protect.
Since you have a 24 volt lithium battery , a class T fuse is realy required for safety. ( the master fuse at the battery).

Amazon.com : Class t fuse

www.amazon.com

Based of your previous post that implied a modest DC load, I am surprised you opted for a 24 volt system and a 3000 watt inverter.

I suggest once you have decided on system that you post a detailed circuit diagram for appraisal.

Mike

 

[Kayte]

This link in Resources may help with fuses,

DC Fuse and breaker Sizing and Placement

To get the paper, click on the orange button at the top of the page. The attached presentation gives the fundamentals for picking fuse/breaker sizes and describes where in the circuit they should be placed. You can download the presentation...

diysolarforum.com

Midi and mega fuses are OK after the buss bar but the 'master' fuse at the battery needs special selection.
If the battery is lead acid then MRBF fuse is acceptable, however at 24 volts, for a lithium battery, a higher specified fuse is recomended.

Fuses have a maximum current interrupt rating. Depending on the energy source there is a possibility a very high current could flow through the fuse. Although the fuse element would fail there is a possibility the energy would 'jump the gap', thus damaging the circuits the fuse was intended to protect.
Since you have a 24 volt lithium battery , a class c fuse is realy required for safety. ( the master fuse at the battery).

Amazon.com : Class t fuse

www.amazon.com

Based of your previous post that implied a modest DC load, I am surprised you opted for a 24 volt system and a 3000 watt inverter.

I suggest once you have decided on system that you post a detailed circuit diagram for appraisal.

Mike

thanks Mike for the links. Hopefully I can figure out which class c fuse I need before the return window closes on the terminal fuse.

Yes, the 24v system and 3000w inverter is over-kill but maybe in the future I'll add more load. Maybe a mini split air conditioner. Or I can use the inverter in another application in the future. Or my usage will be more than I expect.

I will post a diagram once figured out.
It's so confusing to me. 7 or so years ago when I started researching this - Will was still in the RV- things were so different. I bought items then but so much has changed now and the systems are getting Huge! so the current systems I see don't apply to me. Heck, back then lithium was still on the cusp and Will was building his own batteries. I'm glad I didn't go that route! I didn't realize it would be so many years later before I could start building my system. Now decent and adequate plug and play systems are available and affordable. Still don't think I'd go that direction, but maybe. It'd save me a lot of frustration and I could probably sleep at night instead of laying awake trying to figure things out. I wasn't able to fall asleep until 4:30 this morning. I did use the time to ask questions here and do More! research.

This stuff might be easy for you but I can tell you anything you need to know about health and nutrition. Easy peasy!

 

[Kayte]

This link in Resources may help with fuses,

DC Fuse and breaker Sizing and Placement

To get the paper, click on the orange button at the top of the page. The attached presentation gives the fundamentals for picking fuse/breaker sizes and describes where in the circuit they should be placed. You can download the presentation...

diysolarforum.com

Midi and mega fuses are OK after the buss bar but the 'master' fuse at the battery needs special selection.
If the battery is lead acid then MRBF fuse is acceptable, however at 24 volts, for a lithium battery, a higher specified fuse is recomended.

Fuses have a maximum current interrupt rating. Depending on the energy source there is a possibility a very high current could flow through the fuse. Although the fuse element would fail there is a possibility the energy would 'jump the gap', thus damaging the circuits the fuse was intended to protect.
Since you have a 24 volt lithium battery , a class c fuse is realy required for safety. ( the master fuse at the battery).

Amazon.com : Class t fuse

www.amazon.com

Based of your previous post that implied a modest DC load, I am surprised you opted for a 24 volt system and a 3000 watt inverter.

I suggest once you have decided on system that you post a detailed circuit diagram for appraisal.

Mike

As usual, more confused with more information I get. I see on the chart T fuses, Anl, and mega. Don't see C fuses. You posted a link for T fuses. Was this so I could see what a T fuse is or is this what you are recommending? You said C fuse is required. Is a T and C fuse the same thing?

 

[mikefitz]

You said C fuse is required

My error, a 'senior' moment. Class T is correct. Sorry for the confusion.

In mitigation I am working on a phone with very poor Internet in a RV whilst touring Ireland. Cannot always review what I have written

 

[Kayte]

My error, a 'senior' moment. Class T is correct. Sorry for the confusion.

In mitigation I am working on a phone with very poor Internet in a RV whilst touring Ireland. Cannot always review what I have written

 

[Kayte]

What I have so far. I need to figure out the fuses and appropriate shore charger and everything in between.
https://a.co/d/9vj4U4W solar charge controller
https://a.co/d/hsFn9ak remote meter for CC
https://a.co/d/iOivs02 3000w inverter
https://a.co/d/7AVzlUG circuit breaker
https://a.co/d/7gZZhYe converter
https://a.co/d/6Kh4wUT multimeter, 100a shunt
https://a.co/d/5TaafRb 2 busbars 1 for + and 1 for -
https://a.co/d/crsqVjC on/off switch
https://a.co/d/aQVAWV7 distribution fuse block
I have the 10g pv cables

 

[rodrick]

What I have so far. I need to figure out the fuses and appropriate shore charger and everything in between.
https://a.co/d/9vj4U4W solar charge controller
https://a.co/d/hsFn9ak remote meter for CC
https://a.co/d/iOivs02 3000w inverter
https://a.co/d/7AVzlUG circuit breaker
https://a.co/d/7gZZhYe converter
https://a.co/d/6Kh4wUT multimeter, 100a shunt
https://a.co/d/5TaafRb 2 busbars 1 for + and 1 for -
https://a.co/d/crsqVjC on/off switch
https://a.co/d/aQVAWV7 distribution fuse block
I have the 10g pv cables

Your 100 amp shunt is undersized, your inverter alone can exceed its capacity
I would also get a littlefuse or blue sea or other top brand breaker some of the cheaper ones don’t work well

 

[mikefitz]

Shunt is poor quality,

https://www.amazon.com/Victron-SmartShunt-500AMP-Bluetooth-Battery/dp/B0856PHNLX/ref=sr_1_5?crid=1IISGLDH5E5R2&keywords=victron+smart+shunt+500a&qid=1695198967&sprefix=Victron+smart+shunt%2Caps%2C323&sr=8-5

Circuit breaker, recomended not to use, use fuse instead.

More comments later

 

[mikefitz]

More on the circuit breaker, 50 amp , its OK to use this as an isolator between panels and charge controler, not ideal but can be used is this application.
Because you have a 3000 watt Inverter in a 24 volt system there are going to be high current in the cables feeding the inverter , Current taken by the inverter will be 3000 / 25, ( under load mid charge, battery volts will be around 25 volts.), 120 amps for an ideal world, however there will be conversion losses, so work with 150 amps as the expected maximum current in the Inverter cables.

Part 1: Choosing the Correct Wire Size for a DC Circuit - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

So 1 AWG cable, (50mm2 )
This cable from battery terminals to buss bars, buss bars to inverter.
Master fuse at battery, 200 amps class T
Refer to diagram in above post, this cable will also be used for the shunt, isolating switch and 'master' fuse , advise fitting the fuse/fuse holder as close as practical to battery terminal. Fit before isolator not as shown in the diagram.

From the positive buss bar you need fuses feeding the, solar controler, 24 to 12 converter, no fuse needed for the inverter as the cable size is the same as from battery, main fuse will protect. Solar controller fuse 50A, converter fuse 40A, use Midi link fuse plus fuse holder.
Cable 8AWG, (10mm2)

Converter output to fuse box 8AWG cable.

Unless there is a local shop that can terminate cables you will need cable lugs and tool to compress on to cable. The cable lugs have two dimensions to consider, the cable size and the eye diameter, the eye diameter will vary so you will need a selection , either measure or refer to device data.

Mike

 

[RV8R]

thanks Mike for the links. Hopefully I can figure out which class c fuse I need before the return window closes on the terminal fuse.

Yes, the 24v system and 3000w inverter is over-kill but maybe in the future I'll add more load. Maybe a mini split air conditioner. Or I can use the inverter in another application in the future. Or my usage will be more than I expect.

I will post a diagram once figured out.
It's so confusing to me. 7 or so years ago when I started researching this - Will was still in the RV- things were so different. I bought items then but so much has changed now and the systems are getting Huge! so the current systems I see don't apply to me. Heck, back then lithium was still on the cusp and Will was building his own batteries. I'm glad I didn't go that route! I didn't realize it would be so many years later before I could start building my system. Now decent and adequate plug and play systems are available and affordable. Still don't think I'd go that direction, but maybe. It'd save me a lot of frustration and I could probably sleep at night instead of laying awake trying to figure things out. I wasn't able to fall asleep until 4:30 this morning. I did use the time to ask questions here and do More! research.

This stuff might be easy for you but I can tell you anything you need to know about health and nutrition. Easy peasy!

Hi @Kayte

Posting you diagram now would greatly help us help you ,,, even if just a pencil in version of what you have & without all the details. Easier to look at a visual reference than read volumes of words.

Electrical design is driven primarily by the “loads” or the things you want to run. Do you have a load chart? If so also very helpful to post that. If not maybe a list of what you want to run.

Also, info on what your are installing this system in would help. I assume some sort of van, but I don’t like to assume. If in a vehicle, and you intend on alternating charging the year, make, model info here will also help us to provide useful information.

 

[mikefitz]

Re battery monitoring
The Victron Smart shunt is at the top of the range, units a little lower in cost ,

500A Battery Monitor With Shunt

Renogy's 500A Solar Batter Monitor, A fantastic addition for your solar system, Featured with Battery Monitor With Shunt, battery shunt manager. Free Shipping

www.renogy.com

You mentioned shore power, thus would be needed for a battery charger, 24v, 16 amps

Blue Smart IP22 Charger - Victron Energy

The Blue Smart IP22 Charger is the new professional battery charger with built-in bluetooth. Find a Victron Energy dealer near you.

www.victronenergy.com

The DC output connects to the buss bars with a suitable fuse. 30 amp Midi.

If you intend to have distributed AC outlets , ( at least one outlet for the charger) then there is a need for at least AC over current and isolation between the inlet socket and stuff in the van . Dont worry too much about the AC side at this stage.

It would help if you indicated which part of the world you are in so the links and terminology match.

Tools,

What tools do I need to put electrics into my van? — Offgrid Power Solutions

We often get asked what tools we recommend to build offgrid power solutions in vans. Over the years of working with building electrical systems in vans/boats/cabins/overlanders, we've used a wide range of tools to build our solutions. A lot of these tools are not common tools that you can just buy i

offgridpower.solutions

The hydraulic crimp tool for the larger lugs is recomended, depending on lug quality you may need to make two passes, once with the supposed correct set of dies and a second pass with the next sized own .

You will need a volt meter, I recomend the unit that has a DC clamp meter, ( make sure it can measure DC current, alternatives that seem similar may only measure AC current)

https://www.amazon.com/VENLAB-Multimeter-Auto-ranging-Temperature-Capacitance/dp/B0BVZJ7NCZ/ref=sr_1_2_sspa?crid=3U821BGDVVNY1&keywords=dc%2Bclamp%2Bmeter&qid=1695225160&sprefix=Dcclamp%2Bmeter%2Caps%2C445&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[Kayte]

This will be in a '22 Ford Transit 250 Cargo Van. I hadn't planned on alternator charging because my understanding is that it's hard on the alternator and I didn't upgrade the alternator when I purchased the van new. I'd also have to install a disconnect switch. Everyone seems to charge with the alternator so maybe I'm wrong. It would be nice to have that option. I'm in the US.
2 AC outlets 1 in garage, 1 in galley
Here is a list of load items. Some may not be used but including in case.
600wh 24v fridge
231wh Instant Pot 700w
144wh 8 LED puck lights 3w each
1wh 2 LED garage lights 3w each
24wh 2 Bed lights w USB
4.8wh H20 pump
2.5wh 2 exterior LED lights 5w each
160wh MaxAir Fan 56w high 2.4w low
240wh 3 personal fans w/lights 13.2w high 7.2w low
120wh phone charging 60w
180wh computer charging 40w
? 12v diesel heater 8amp startup, 2a running
? Rechargeable blender 30w
50wh hair blower 1400w

approx 1800wh round up to 2000wh
Diagram coming up as soon as I decipher all the info presented. Which I'm very, very grateful for.

 

[RV8R]

I have built 2 Promasters & pretty much 100% charge from the alternator & mostly 12vdc for electrical use.

My understanding is the Transit is a smart alternator & you are going with 24vdc battery bank, so maybe a 12vdc to 24vdc DC2DC charger ?

What are the DIYers doing on the Transit Forum ?

I will look over the info you listed above when I get a chance.

 

[Kayte]

Re battery monitoring
The Victron Smart shunt is at the top of the range, units a little lower in cost ,

500A Battery Monitor With Shunt

Renogy's 500A Solar Batter Monitor, A fantastic addition for your solar system, Featured with Battery Monitor With Shunt, battery shunt manager. Free Shipping

www.renogy.com

You mentioned shore power, thus would be needed for a battery charger, 24v, 16 amps

Blue Smart IP22 Charger - Victron Energy

The Blue Smart IP22 Charger is the new professional battery charger with built-in bluetooth. Find a Victron Energy dealer near you.

www.victronenergy.com

The DC output connects to the buss bars with a suitable fuse. 30 amp Midi.

If you intend to have distributed AC outlets , ( at least one outlet for the charger) then there is a need for at least AC over current and isolation between the inlet socket and stuff in the van . Dont worry too much about the AC side at this stage.

It would help if you indicated which part of the world you are in so the links and terminology match.

Tools,

What tools do I need to put electrics into my van? — Offgrid Power Solutions

We often get asked what tools we recommend to build offgrid power solutions in vans. Over the years of working with building electrical systems in vans/boats/cabins/overlanders, we've used a wide range of tools to build our solutions. A lot of these tools are not common tools that you can just buy i

offgridpower.solutions

The hydraulic crimp tool for the larger lugs is recomended, depending on lug quality you may need to make two passes, once with the supposed correct set of dies and a second pass with the next sized own .

You will need a volt meter, I recomend the unit that has a DC clamp meter, ( make sure it can measure DC current, alternatives that seem similar may only measure AC current)

https://www.amazon.com/VENLAB-Multimeter-Auto-ranging-Temperature-Capacitance/dp/B0BVZJ7NCZ/ref=sr_1_2_sspa?crid=3U821BGDVVNY1&keywords=dc%2Bclamp%2Bmeter&qid=1695225160&sprefix=Dcclamp%2Bmeter%2Caps%2C445&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

Question about the Charger - I've seen diagrams where the charger is connected to the fuse block (distribution) and not the battery. I thought this is for charging the battery so should be connected there. If this is correct, do I need a charger for 24v since that is what my battery is? And does the 3 output mean so it can be connected to 3 batteries? Thnx and much gratitude. K-
I'm leaning to purchasing the Victron Smart Shunt as I'm not as impressed with the Renogy products though right now it's $59 on Amazon compared to $131 for the Victron. At that price I can buy two Renogy.

 

[Kayte]

I have built 2 Promasters & pretty much 100% charge from the alternator & mostly 12vdc for electrical use.

My understanding is the Transit is a smart alternator & you are going with 24vdc battery bank, so maybe a 12vdc to 24vdc DC2DC charger ?

What are the DIYers doing on the Transit Forum ?

I will look over the info you listed above when I get a chance.

It seems that with the smart alternator and a B2B it will work without stress on the alternator but I can't say I actually saw a definitive answer on the Transit forum. I didn't know the transit has a smart alternator. I'm so grateful people want to share what they know.

 

[RV8R]

It seems that with the smart alternator and a B2B it will work without stress on the alternator but I can't say I actually saw a definitive answer on the Transit forum. I didn't know the transit has a smart alternator. I'm so grateful people want to share what they know.

I do not know a lot about the Transits. @HarryN might chime as he has Transit experience & knows about the smart alternator. He also would know about 12vdc to 24vdc B2B chargers. If you are near San Fran, also a great source of assistance.

Depending on your use & area, Alternator charging can be the way to go. We almost 100% charge our batteries by alternator.

At this point you have purchased items without knowing your design. I recommend you try to identify your use / needs, & we can vet your design here before you purchase more items. There will be some differences in opinions of course ,,, eg depending on the cost I would buy a BM712 smart over the Smart Shunt ,,, it might have some additional features down the road you might like

When I look at your 120vac loads, I believe you can have the inverter off typically unless the need arises “hairdryer etc”. You are planning on a 24vdc fridge & thus not need the inverter on standby. This is an important part of your design criteria as inverters on standby will use up your battery power. @Tomthumb62 might chime in how he setup his, but I am a believer in less is more.

Here is the Cole’s Notes on that topic ?;





lol Thanks @sunshine_eggo for that comment, it makes me laugh every time I read it, as it is just that when someone says “it can be done” ?. Then my expectation is exactly that & I’m all “Yip Ya”