Solar controllers

[Floydo]

Hi
Just about to fit a hard korr 170w solar panel to the roof of my Tdi 130. The second battery is located in the tub.
What solar controller are you guys using and where is the best place to mount them ?
They see quite large and looks like they can get quite hot and need alot of air flow around them.
Thanks for the advice in advance.

[W&KO]

I’ve been using Victron Bluetooth units for a while now, doing a good job and I reckon they are good value for the dollars.

One in the defer, one in the Lux and one on a portable battery.

I wouldn’t call our large and haven’t noticed them getting hot.

https://uploads.tapatalk-cdn.com/20210608/39e319ff0ce3f4d08241ef3313fdb5f9.png

[Rick]

Yup, I've got a Victron as well and I'm happy with it. I mounted it under the driver's seat.

[Tombie]

Yep. Victron!

[Floydo]

Thanks guys, Victron it is.

[DiscoMick]

Korr has solar controllers. I know someone with their MPPT one who is happy with it. Might be worth checking.

[DiscoMick]

Sorry, its a Korr PWM, not MPPT. $89.

[Pen48]

What model Victron?

TIA

[eddy]

KickAss looks the goods Mppt weather proof and good price KickAss 15A Waterproof MPPT Solar Charge Controller | Outdoor Fixed, Flexible & Portable Panels (https://www.australiandirect.com.au/buy/kickass-mppt-solar-controller-15a/KA1224MPPT15A)

[Tombie]

What model Victron?

TIA

Depends on your intended level of panels, power requirements and configuration.


A benefit of Victron over something like the Kickass unit above is the upgrade paths available.

Victron can charge Wet, AGM, Gel and Lithium.

[W&KO]

What model Victron?

TIA

Generally you size it to the amount of solar you intend running

I started with a 75/15 and now have a 100/30, which I should have purchased first up. Hasn’t gone to waste as it now sitting on a portable battery box the kids use.

[Floydo]

What size panel are you running with the Victron 100 / 30 ? I'm running a 170w fixed , heard a 75 / 15 was ok.

[Tombie]

What size panel are you running with the Victron 100 / 30 ? I'm running a 170w fixed , heard a 75 / 15 was ok.

Again it depends how you set them up.

I’ve got 230w (2x115) running on a 75/15 no issues.
It was running 4x100w prior to that.

And here’s the rub. It produces more on the 230w set up than it did with the 400w.

Better panels [emoji41] they’re Victron now!

[W&KO]

What size panel are you running with the Victron 100 / 30 ? I'm running a 170w fixed , heard a 75 / 15 was ok.

Currently running 2x120w, however will more than likely add a 3rd before we roll out the gate, depending on roof rack configuration. We do nudge the 240w at times with current panel.

I have changed my config for the solar blanket by utilizing the unused function on DC-DC. But am now considering leaving the solar blanket home.

Either way having a 100/30 will mean I don’t miss any charge when conditions are perfect. Any changes is low on the list of things on the to do list

75/15 will be fine for a 170w panel.

Seems to many way to do the calculations, depending what you read online.

170w/12v=14a
170w/13v=13a
170w*0.9/12v=12.75a
170w*0.9/13w=11.75a

There is probably a more scientific way……The above calculations is a rough way size a solar regulator

[Tombie]

Not even close to how you size it. [emoji41]

Specs will tell you all you need

[DiscoMick]

Does this site help?

Solar Charge Controller Sizing and How to Choose One - Renogy United States (https://www.renogy.com/blog/solar-charge-controller-sizing-and-how-to-choose-one-/?gclid=CjwKCAjwwqaGBhBKEiwAMk-FtP19XlNybHY_pcgRu06p2D4Douj91AmTDHm7f-3gRW4KIgiIv_ks2xoC4N8QAvD_BwE)

[Tombie]

That’s better :)

Just need to know the specs of panels, and how you plan to configure them.

I initially had 2 in series, then parallel with 2 in series.

[DiscoMick]

These are cheap, but I can't comment on the specs.

Kings MPPT Solar Regulator | 20A Charging | Highly efficient for more power - 4WD Supacentre (https://www.4wdsupacentre.com.au/adventure-kings-20a-mppt-solar-regulator.html)

[Floydo]

Got my 170w Hard Korr panel. Got a Kickass 40w MPPT regulator for a good price. It's a little bigger than I expected. So want be able to mount it next to the battery in the tub. Probably be mounted 1 to 2m from battery. If I run 6 or 8 mm fused cable to the battery that should reduce any voltage drop? About the same distance from panel mounted on roof to regulator. Battery is a 120AH AGM. Thoughts, ideas suggestions.

[Floydo]

Do you need to fuse between your solar panel and your MPPT controller? What size fuse

[Tombie]

Do you need to fuse between your solar panel and your MPPT controller? What size fuse

They are a good idea. I have 2x 10A fuses - 1 in each panels output line. A fuse rated above the panels max Amp output is all thats needed.

Search "inline solar fuse"

[trout1105]

Do you need to fuse between your solar panel and your MPPT controller? What size fuse

I can't see the point of adding a fuse between the panel and the MPPT controller, As long as your MPPT controller is rated at more amps than your panel/panels are capable of producing there shouldn't be any problems.

Have a look on the back of you solar panel/panels to see the max ampage they produce and get an MPPT controller that can accomodate this amount of ampage[thumbsupbig]

The panels on my 79 Series produce 15a MAX and the MPPT contoller is rated at 40a and I have never had a problem in the last 6 years.

[Tombie]

I can't see the point of adding a fuse between the panel and the MPPT controller, As long as your MPPT controller is rated at more amps than your panel/panels are capable of producing there shouldn't be any problems.

Have a look on the back of you solar panel/panels to see the max ampage they produce and get an MPPT controller that can accomodate this amount of ampage[thumbsupbig]

The panels on my 79 Series produce 15a MAX and the MPPT contoller is rated at 40a and I have never had a problem in the last 6 years.

And if that wire chafes through between roof and vehicle in a panel cavity pre-MPPT - what do you think those amps are going to do?

Prevention is better than cure.

[trout1105]

And if that wire chafes through between roof and vehicle in a panel cavity pre-MPPT - what do you think those amps are going to do?

Prevention is better than cure.

This is why you always use a rubber grommets/cable glands when you run the wires through metal and the panel cables are always double insulated. [thumbsupbig]
IF there is an issue with "Chaffing" the usual culprit is a poorly exicuted installation eg. cables not secured, poor crimps/joins and of course not using grommets/cable glands/shielding where they are required.
Ading fuses from/at the panel is just over complicating a very simple installation and IF the panels/wireing are fitted correctly there is absolutely no need for fuses at this point.

176943

[Vern]

Happy to add a relay to a 800mA circuit, not happy to add a fuse to a 10+ amp solar panel, that will not stop burning if under short circuit fault until out of the sunlight. [emoji1][emoji1]

[Tombie]

This is why you always use a rubber grommets/cable glands when you run the wires through metal and the panel cables are always double insulated. [thumbsupbig]
IF there is an issue with "Chaffing" the usual culprit is a poorly exicuted installation eg. cables not secured, poor crimps/joins and of course not using grommets/cable glands/shielding where they are required.
Ading fuses from/at the panel is just over complicating a very simple installation and IF the panels/wireing are fitted correctly there is absolutely no need for fuses at this point.

176943

If my double insulated house wiring is installed correctly then why do they need to install fuses?
And RCDs etc?

Because things happen.

Copper fatigues, insulation breaks down, vibration loosens connections and joints.

This can cause arcs, shorts and hot joints.

Btw, your curve radius on that cable is too tight into that cable gland [emoji41]

[trout1105]

If my double insulated house wiring is installed correctly then why do they need to install fuses?
And RCDs etc?

For the same reasons why these items are used in a 12/24v system between the battery/batteries and whatever they are powering up.
You won't find a fuse from your power line to your house, The power goes into your fuse box and is distributed through the house via fuses from there So why would you need a fuse from your solar panel to your battery?

[johnp38]

A solar panel can only produce its max rated current as per its design /cell limits, so a short doesn't increase its output or damage it.

Put a panel in the sun and short the leads together, it (current) just goes round and round all day no damage as it is working at its ratings. An individual fuse per panel above the max panel current is a waste and will never blow.

Panels in series increase the voltage not the current output.

Panels in parallel increase the current output but not the voltage.

You only use a fuse where the source (panel/array of panels) is capable of supplying more current than the load (pwm/mppt regulator) normally requires and if the load itself faults then the fuse will blow as the panel/array will then put max current into the load.

Example - 2 x 24 volt 5 amp panels in parallel = 24 volts 10 amps output (ignore light conditions)

You have an MPPT regulator charger that is 8-36 volts input but only draws max of 5 amps input to do its job. So within its operating parameters, which exceed the voltage of the panels comfortably, it will draw only what it is designed for by varying its internal resistance.

Should said regulator develop an internal fault it may draw up to the 10 amp self limit of the array, this wont harm the panels but will be burning up the regulator, however your 6 amp fuse placed inline AFTER the panels have been paralleled will blow and stop the current flow.

I can try and clarify if I haven't explained properly.

[Robmacca]

For the same reasons why these items are used in a 12/24v system between the battery/batteries and whatever they are powering up.
You won't find a fuse from your power line to your house, The power goes into your fuse box and is distributed through the house via fuses from there So why would you need a fuse from your solar panel to your battery?


Not sure where u live but here in QLD I can say with 100% that the Power Service cable coming into your house from the street IS fused. It is HIGHLY dangerous not to have it Fused. It's usually located on the Pole or the Underground Pillar box on the footpath for those in underground powered estates.

[Robmacca]

I'm fairly (?) sure that the Solar Panels on your Roof are not fused either (ie: between Solar Panel & invertor), but there should be an isolating switching near the panels to isolate the solar so if needed, work can be carried out on the invertor...



A solar panel can only produce its max rated current as per its design /cell limits, so a short doesn't increase its output or damage it.

Put a panel in the sun and short the leads together, it (current) just goes round and round all day no damage as it is working at its ratings. An individual fuse per panel above the max panel current is a waste and will never blow.

Panels in series increase the voltage not the current output.

Panels in parallel increase the current output but not the voltage.

You only use a fuse where the source (panel/array of panels) is capable of supplying more current than the load (pwm/mppt regulator) normally requires and if the load itself faults then the fuse will blow as the panel/array will then put max current into the load.

Example - 2 x 24 volt 5 amp panels in parallel = 24 volts 10 amps output (ignore light conditions)

You have an MPPT regulator charger that is 8-36 volts input but only draws max of 5 amps input to do its job. So within its operating parameters, which exceed the voltage of the panels comfortably, it will draw only what it is designed for by varying its internal resistance.

Should said regulator develop an internal fault it may draw up to the 10 amp self limit of the array, this wont harm the panels but will be burning up the regulator, however your 6 amp fuse placed inline AFTER the panels have been paralleled will blow and stop the current flow.

I can try and clarify if I haven't explained properly.

[trout1105]

Not sure where u live but here in QLD I can say with 100% that the Power Service cable coming into your house from the street IS fused. It is HIGHLY dangerous not to have it Fused. It's usually located on the Pole or the Underground Pillar box on the footpath for those in underground powered estates.

Yes I do have a pole fuse But that won't stop me getting electricuted because it takes quite a massive short to blow that partiular fuse.

[Gav 110]

Not sure where u live but here in QLD I can say with 100% that the Power Service cable coming into your house from the street IS fused. It is HIGHLY dangerous not to have it Fused. It's usually located on the Pole or the Underground Pillar box on the footpath for those in underground powered estates.

Here in WA only some of the overhead connections are fused, most rural at the transformer and some domestic
None of the underground consumer mains are fused, not individually anyway, I would assume western power have (high current) fuses at the transformer
[emoji481][emoji481]
Gav

[Robmacca]

Yes I do have a pole fuse But that won't stop me getting electricuted because it takes quite a massive short to blow that partiular fuse.

Correct as its rated to protect the service cable coming in... RCD's are really the only thing that will hopefully protect u from getting electrocuted... generally ;)

[trout1105]

Correct as its rated to protect the service cable coming in... RCD's are really the only thing that will hopefully protect u from getting electrocuted... generally ;)

Which brings us back to my point about there being no fuses that will protect the house nor occupiers between the power pole and the house switchboard [thumbsupbig]
The pole fuse is there to protect the power grid and not the house.

[Robmacca]

Here in WA only some of the overhead connections are fused, most rural at the transformer and some domestic
None of the underground consumer mains are fused, not individually anyway, I would assume western power have (high current) fuses at the transformer
[emoji481][emoji481]
Gav

WOW, that is surprising and very dangerous too (ie for a fault between the pole and your switchboard the Fault Current could burn your house down if your house mains were not fused)...
I work for Utility business here in QLD and ALL premises (Overhead/Underground) have to be individually Fused as u do not want a fault in someone's premise to effect the whole area by isolating back at the local distribution transformer. This would be a nightmare to find/locate as well.


I would be very surprised it that is the case in WA. In the Outback it maybe different but still hard to believe. On SWER lines there is usually individual Transformers for each remote customer and I still think that they too would have a LV fuse at the Transformer.


When it comes to a full large solar system u start talking about electronics, etc which is above my head...

[Robmacca]

Which brings us back to my point about there being no fuses that will protect the house nor occupiers between the power pole and the house switchboard [thumbsupbig]
The pole fuse is there to protect the power grid and not the house.

No not exactly... It's there to protect the CABLE from the pole down into your switchboard only and should be rated according to the size cables u have...

[Gav 110]

WOW, that is surprising and very dangerous too (ie for a fault between the pole and your switchboard the Fault Current could burn your house down if your house mains were not fused)...
I work for Utility business here in QLD and ALL premises (Overhead/Underground) have to be individually Fused as u do not want a fault in someone's premise to effect the whole area by isolating back at the local distribution transformer. This would be a nightmare to find/locate as well.


I would be very surprised it that is the case in WA. In the Outback it maybe different but still hard to believe. On SWER lines there is usually individual Transformers for each remote customer and I still think that they too would have a LV fuse at the Transformer.


When it comes to a full large solar system u start talking about electronics, etc which is above my head...

Definitely no protection or isolator between the underground power dome and the house

There is a meter fuse to protect the meter and as we are no longer allowed to work on or near live electrical equipment, we are now allowed to use that fuse to isolate before working on a switchboard

Back on topic
A fuse at the panels sounds like a feasible idea but it adds another point in which can cause a problem, heat, moisture, dust etc all have the possibility to cause the fuse to arc/blow
As Trout has said if you protect the cable well enough you won’t have a problem
If by chance he cable does short out, the voltage isn’t high enough for the cable to continue burning and cause more damage

Like rooftop solar isolators, I believe a fuse would cause more problems

[emoji481][emoji481][emoji481]
Gav

[Vern]

Definitely no protection or isolator between the underground power dome and the house

There is a meter fuse to protect the meter and as we are no longer allowed to work on or near live electrical equipment, we are now allowed to use that fuse to isolate before working on a switchboard

Back on topic
A fuse at the panels sounds like a feasible idea but it adds another point in which can cause a problem, heat, moisture, dust etc all have the possibility to cause the fuse to arc/blow
As Trout has said if you protect the cable well enough you won’t have a problem
If by chance he cable does short out, the voltage isn’t high enough for the cable to continue burning and cause more damage

Like rooftop solar isolators, I believe a fuse would cause more problems

[emoji481][emoji481][emoji481]
GavEver tried to make an arc with a 40V panel? You'll be surprised

[Gav 110]

Ever tried to make an arc with a 40V panel? You'll be surprised

I have on a 270watt 38voc 9isc
It will only burn for a few seconds before the burnt insulation creates enough of a barrier that the arc will stop
If you “draw” an arc by holding the cables apart you can keep it going for a while

You need the panel to be putting out full current to make it happen

You ever seen a parallel string at around 700volts arc?

That’ll scare the **** out of ya (and anyone else in sight)[emoji90]

[Vern]

I have on a 270watt 38voc 9isc
It will only burn for a few seconds before the burnt insulation creates enough of a barrier that the arc will stop
If you “draw” an arc by holding the cables apart you can keep it going for a while

You need the panel to be putting out full current to make it happen

You ever seen a parallel string at around 700volts arc?

That’ll scare the **** out of ya (and anyone else in sight)[emoji90]I've seen plenty, i do solar for a living. Dc just keeps on burning.

[Gav 110]

I've seen plenty, i do solar for a living. Dc just keeps on burning.

You’ve had the boys **** up there connections as well aye

That one was the last time I left the guys to sort out the array wiring
I pulled an arc almost a meter[emoji90]
Should’ve felt the heat coming off that one, I didn’t need to hit the tanning salon that day[emoji1531]
The guys there that day still call me the magician
Arcs and sparks like Merlin 🧙

[scarry]

Yes in Qld we have pole fuses,isolates the mains to the house,and obviously the house.Easy to undo and drops it all off.
Commercial premises have them as well,often 3 phase.

The place we have in NSW,there is no pole fuse,just a large 100A or it could be 80A i think it is, fuse in the meter box.No protection from pole to our meter box which seems a bit odd.
So to isolate everything,a wire at the pole would have to be disconnected while alive i presume.
Unless there is a switch on the pole,but i cant see one.

[Robmacca]

Yes in Qld we have pole fuses,isolates the mains to the house,and obviously the house.Easy to undo and drops it all off.
Commercial premises have them as well,often 3 phase.

The place we have in NSW,there is no pole fuse,just a large 100A or it could be 80A i think it is, fuse in the meter box.No protection from pole to our meter box which seems a bit odd.
So to isolate everything,a wire at the pole would have to be disconnected while alive i presume.
Unless there is a switch on the pole,but i cant see one.

Well... there u go, I had always thought what we do here in Qld on the LV network would be the same across the country as it just makes sense to have a fuse at every consumers Mains which makes isolating the Customer's Premise easy and protects the service cable as well. Not having a fuse at a customers premise is very dangerous if there was a short circuit as u would have the distribution Transformers fault current just pumping into the short circuit until it just melted the wire or caused a fire. It just doesn't make sense... but there u go, nothing is built to the same standard across the country...

[Gav 110]

Well... there u go, I had always thought what we do here in Qld on the LV network would be the same across the country as it just makes sense to have a fuse at every consumers Mains which makes isolating the Customer's Premise easy and protects the service cable as well. Not having a fuse at a customers premise is very dangerous if there was a short circuit as u would have the distribution Transformers fault current just pumping into the short circuit until it just melted the wire or caused a fire. It just doesn't make sense... but there u go, nothing is built to the same standard across the country...

We have the fuse

Just protecting the meter

If they disconnect your power, all they do is remove the fuse

[Tombie]

No not exactly... It's there to protect the CABLE from the pole down into your switchboard only and should be rated according to the size cables u have...

That’s the set up on our place.

50a fuse on the corner of the house supply, larger units visible at the “pole”

[scarry]

We have the fuse

Just protecting the meter

If they disconnect your power, all they do is remove the fuse

So no protection from pole to meter box,same as NSW?

I would much rather a pole fuse,but i am no expert.
We have blown a few over the years.....[bighmmm]

i remember being with a tradie when i was an apprentice,at a picture theatre,full of people.
We were fixing the AC,and blew a pole fuse,well two out of the 3, 3 phase.[bigsad][biggrin]
That day became rather interesting[biggrin]

[Gav 110]

So no protection from pole to meter box,same as NSW?

I would much rather a pole fuse,but i am no expert.
We have blown a few over the years.....[bighmmm]

i remember being with a tradie when i was an apprentice,at a picture theatre,full of people.
We were fixing the AC,and blew a pole fuse,well two out of the 3, 3 phase.[bigsad][biggrin]
That day became rather interesting[biggrin]

Nowadays all unprotected consumers mains that run through roof spaces have to be run in HD conduit. Older places it wasn’t a requirement so conflicts with new laws where we must isolate the wiring in the roof space if you need to enter for work, all trades not just electricians.
I’ve found a few old places with contactors put in the consumer mains and being controlled by the main switch, free power taken off the dead side of contactor.

I’ve been out to a few **** ups over they years, usually taking out shopping centres 🤭
I’ve been called out to jobs where fridgies have replaced burnt out terminal strips with earth/neutral links🤣🤣
And can’t work out why it goes bang every time they turn the breaker back on
Eventually when the whole shopping Center goes out, call god, oops I mean an electrician
[emoji1531][emoji1531][emoji1531]

[DiscoMick]

Can't comment on your set-up, but I know with the Enerdrive set-up in our caravan Enerdrive recommends using 70amp fuses with its 40 amp DC-DC charger and unregulated solar panels. Also recommends 70amp fuses both ends of the vehicle-caravan Anderson plugs connection.
Got my 170w Hard Korr panel. Got a Kickass 40w MPPT regulator for a good price. It's a little bigger than I expected. So want be able to mount it next to the battery in the tub. Probably be mounted 1 to 2m from battery. If I run 6 or 8 mm fused cable to the battery that should reduce any voltage drop? About the same distance from panel mounted on roof to regulator. Battery is a 120AH AGM. Thoughts, ideas suggestions.

[trout1105]

Can't comment on your set-up, but I know with the Enerdrive set-up in our caravan Enerdrive recommends using 70amp fuses with its 40 amp DC-DC charger and unregulated solar panels. Also recommends 70amp fuses both ends of the vehicle-caravan Anderson plugs connection.

Wouldn't it be a better idea to have a solar regulator between the panels to the charger instead of relying on fuses?
Also unless you have Very heavy duty wireing a 70a fuse sounds a bit big to me.

[johnp38]

Wouldn't it be a better idea to have a solar regulator between the panels to the charger instead of relying on fuses?
Also unless you have Very heavy duty wireing a 70a fuse sounds a bit big to me.

I'm guessing the fuses are between the DC-DC unit and load, not between panels and DC-DC unit

[trout1105]

I'm guessing the fuses are between the DC-DC unit and load, not between panels and DC-DC unit

That doesn't make sense.
Why would you put a 70A fuse between a 40A charger and the load/batteries?

[johnp38]

That doesn't make sense.
Why would you put a 70A fuse between a 40A charger and the load/batteries?

Because you don't fuse the panels on a camper as there aren't enough to exceed your fuse rating making it a moot point.

You fuse the load to prevent the dcdc unit feeding a short if something happens to the load and to protect the batteries if the dcdc unit cocks up and the batteries back feed into it.

that unit is rated at 45V input 850 Watts (Solar) so that's only 20 amps input from the panels so never gonna blow the fuse if you put one in the panel wiring..

I just went on the enerdrive site and you might want to do the same.

DC2DC - In Vehicle Installation (enerdrive.com.au) (https://enerdrive.com.au/wp-content/uploads/2018/12/DC2DC-In-Vehicle-Installation-1.pdf)

[DeanoH]

.......................................... Also recommends 70amp fuses both ends of the vehicle-caravan Anderson plugs connection.

When the Anderson plug falls out and drags along the road shorting out (or other cabling failure) the fuses protect the cabling, battery(s), alternator and charge in BOTH batterys :)

How do I know this ? "been there done that" :(

Deano :)

[DeanoH]

.................................. Enerdrive recommends using 70amp fuses with its 40 amp DC-DC charger and unregulated solar panels.

This is because the 'Enerdrive DC2DC+ ePower Charger' charger already has its own inbuilt MPPT solar controller.

It is a very, very bad idea to connect solar panels directly to a battery without a solar regulator/controller. Voc of a nominal 12v panel is around 21v and can(will) destroy the battery.

Similarly it is a bad idea to connect a solar reg into another solar reg to charge your battery. It won't destroy the battery by overcharging (no solar reg) but will undercharge (battery never reaches capacity) perhaps leading to sulphation and further loss of capacity if a lead acid battery.
This is exactly what I found a couple of years ago in a very expensive high end camper. The owner stated the battery voltage had never got above 12.x volts in the 3 years he had owned it (from new). I re-configured the solar correctly and all was good :)
Being Australias' most expensive/futuristic camper van (at the Time) didn't guarantee the people that designed/fitted and tested it had a clue about setting up the electrics.

Deano :)

[trout1105]

Because you don't fuse the panels on a camper as there aren't enough to exceed your fuse rating making it a moot point.

You fuse the load to prevent the dcdc unit feeding a short if something happens to the load and to protect the batteries if the dcdc unit cocks up and the batteries back feed into it.

that unit is rated at 45V input 850 Watts (Solar) so that's only 20 amps input from the panels so never gonna blow the fuse if you put one in the panel wiring..

I just went on the enerdrive site and you might want to do the same.

DC2DC - In Vehicle Installation (enerdrive.com.au) (https://enerdrive.com.au/wp-content/uploads/2018/12/DC2DC-In-Vehicle-Installation-1.pdf)

With any 12v/24v solar setup on a van/vehicle I cant see any value in adding a fuse between the panel and the regulator.
With the enerdrive units I can't fathom why with say a 40A unit they recommend a 70A fuse between the battery/load and the unit when common sense tells me that a fuse less than the 40A rating for that application seems more appropriate.

The only fuses I use on my 12v solar sytem are located AFTER the battery and I haven't had any dramas with this setup over the many years that I have been using them.
With the exception of the winch circuit breakers on my 4WD's and boats the largest fuses I have used are 30A which allows plenty of current to run my fridges, compressor or whatever other 12v appliance I want to use, 70A seems rather excessive for this application as does running 70A fuses on the rear anderson plugs as the vast majority of anderson plugs fitted are only rated at 50A.

[Geedublya]

With any 12v/24v solar setup on a van/vehicle I cant see any value in adding a fuse between the panel and the regulator.
With the enerdrive units I can't fathom why with say a 40A unit they recommend a 70A fuse between the battery/load and the unit when common sense tells me that a fuse less than the 40A rating for that application seems more appropriate.

The only fuses I use on my 12v solar sytem are located AFTER the battery and I haven't had any dramas with this setup over the many years that I have been using them.
With the exception of the winch circuit breakers on my 4WD's and boats the largest fuses I have used are 30A which allows plenty of current to run my fridges, compressor or whatever other 12v appliance I want to use, 70A seems rather excessive for this application as does running 70A fuses on the rear anderson plugs as the vast majority of anderson plugs fitted are only rated at 50A.

Solar regulator went short, wiring between reg and battery fried, very lucky it didn’t set camper alight. This was wiring already installed when camper was purchased.
Lesson learnt, a battery can provide 100s of amps, any input or output should be fused if possible. Admittedly starter motors and alternators usually aren’t fused due to the very high current involved.

[trout1105]

Solar regulator went short, wiring between reg and battery fried, very lucky it didn’t set camper alight. This was wiring already installed when camper was purchased.
Lesson learnt, a battery can provide 100s of amps, any input or output should be fused if possible. Admittedly starter motors and alternators usually aren’t fused due to the very high current involved.

A 70A fuse for a 40A regulator won't provide much protection either.
I have never had a solar regulater fry itself even the ones on my portable panels in the rain havent failed, A loose wire on your failed regulator perhaps?

[johnp38]

A 70A fuse for a 40A regulator won't provide much protection either.
I have never had a solar regulater fry itself even the ones on my portable panels in the rain havent failed, A loose wire on your failed regulator perhaps?

It will protect the flatteries if the regulator shorts internally, the batteries will provide more than 70 amps and blow the fuse.

You're looking at it from the regulator end as the source and batteries as load, look at it from the batteries perspective as the source and the regulator as the load and suddenly the 70 amp fuse between the dcdc 40 amp unit and batteries has a purpose.

But yes a 50 amp fuse would suffice.

Of course if the regulator drops dead but turns into a load that only draws 20 amps out of the batteries that fuse becomes useless.

DC auto wiring is easy - [ power source +ve / fuse / switch / load / power source -ve ] - will get most things done. Even the complicated circuits can be broken down into simple individual runs if you spend a little time to understand what you're looking at.

Old school positive earth is the same except the negative battery terminal is the source and the positive terminal goes to chassis.

I like to run my trailer sockets and anderson connectors back to an earth bus bar near the battery.

[trout1105]

It will protect the flatteries if the regulator shorts internally, the batteries will provide more than 70 amps and blow the fuse.

You're looking at it from the regulator end as the source and batteries as load, look at it from the batteries perspective as the source and the regulator as the load and suddenly the 70 amp fuse between the dcdc 40 amp unit and batteries has a purpose.

But yes a 50 amp fuse would suffice.

Of course if the regulator drops dead but turns into a load that only draws 20 amps out of the batteries that fuse becomes useless.

DC auto wiring is easy - [ power source +ve / fuse / switch / load / power source -ve ] - will get most things done. Even the complicated circuits can be broken down into simple individual runs if you spend a little time to understand what you're looking at.

Old school positive earth is the same except the negative battery terminal is the source and the positive terminal goes to chassis.

I like to run my trailer sockets and anderson connectors back to an earth bus bar near the battery.

It is my understanding that MPPT controllers are fitted with a fuse for the battery output internally.

177050

[johnp38]

It is my understanding that MPPT controllers are fitted with a fuse for the battery output internally.

177050

That circuit sure is. May not apply to all brands / designs .

But if the user manual/wiring guide says put one in the line I just follow the installation guide not over think it.

[DiscoDB]

An in-line resettable fuse between the panel and solar regulator can also be used as an isolator.

Useful if changing batteries where you need to connect the battery first before the solar panels to establish the operating voltage (if you have a dual voltage regulator).

My Victron charge controller on my trailer does not require a fuse between the solar panels and regulator, but I still added so I could use as an isolator.

[trout1105]

An in-line resettable fuse between the panel and solar regulator can also be used as an isolator.

Useful if changing batteries where you need to connect the battery first before the solar panels to establish the operating voltage (if you have a dual voltage regulator).

My Victron charge controller on my trailer does not require a fuse between the solar panels and regulator, but I still added so I could use as an isolator.

A very simple solution to this problem is to change the batteries at night or just disconnect the battery feed from the solar controller IF it worries you[thumbsupbig]
There is absolutely NO need of a fuse between the panels and the controller.

[DiscoDB]

Actually was simpler to add an inline circuit breaker fuse with manual reset.

May not be needed but it is very good practice.

Cheap insurance.