Reassure me about basic setup (please!)

[Freshtrax]

Just checking before I start my electrical install at the weekend that I've not missed anything major, particular around fuses / isolation etc.
I'm fitting a Victron DC to DC, a Fogstar 105 Ah (heater and bluetooth built in), a Victron MPPT and Victron 185w solar panel.
Initially will only be powering lights and fridge, with diesel heater and maybe water pump added later.
I'll try and make the questions sensible!

- For the DC to DC, I'll run 16mm cable with a 60amp midi fuse to the DC to DC under drivers seat.

Q1. Does the positive from the DC to DC to the Fogstar also need to be fused? (I think it does).

- For the solar, I'll put a 30amp midi fuse on the positive wire to the MPPT.

Q2. Do I wire the MPPT straight to the Fogstar just like the DC to DC?
Q3. Does the positive between the MPPT to the Fogstar (assuming I'm correct with Q2) also need fusing?
Q4. Shall I isolate the extension leads that go into the MPPT as well as fuse it?
Q5. Can I just turn off the MPPT and DC to DC in the viltron app if required?

I think that's everything. I'm just worried that when my van isn't being used (there'll be some weeks it's just sat on the drive) that I need to isolate things so the solar MPPT isn't constantly being used. Thank you for any help, much appreciated.

 

[Skyliner33]

No need to put a fuse between solar panel and MPPT.

 

[Howzat]

No need to put a fuse between solar panel and MPPT.

Agreed. The solar isn't gonna run away power wise like a battery can.
so....

A1. Yes.
A2. Yes or use a busbar (better)
A3. The battery can run away power wise so yes, fuse near battery or if using a busbar, between the battery and busbar.
A4. Not sure what you mean by isolate? You mean add an on/off switch? You can but see my answer 5.
A5. Sure, but why would you for solar? Even winter sun will provide some trickle charge to the battery. Can see why you might want to disable DC2DC but a manual switch would 100% ensure it's fully isolated from the SB. I can't see how an app would do this effectively otherwise how would the app work if no power was going to the DC2DC?

 

[Freshtrax]

So don’t fuse dc dc to battery, but do fuse the mppt to battery? Why?

 

[Howzat]

So don’t fuse dc dc to battery, but do fuse the mppt to battery? Why?

No, you're right. Anything to or from the battery should be fused. Apologies. Edited my original post.

 

[Freshtrax]

Thank you! Just want to make sure it's all safe. Good to know not to bother with isolating the solar, saves a connection.

 

[Dellmassive]

FYI....

ANY battery connection MUST be fused to protect its cable.

 

[Sim60]

FYI....

ANY battery connection MUST be fused to protect its cable.

Fused at the battery end of the cable.

 

[Dellmassive]

Yes. As close as potentially possible. Ie a few inches.

Have a look at this before doing anything.

https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

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More info

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[Freshtrax]

Thank you Dell, was reading that this morning!
Not much info about fusing solar, but think 4mm cable will be fine for my 185w panel.

 

[Anakin]

I did fit a solar panel isolator switch after reading about it on here. I can’t remember the reason though

 

[ginkster]

Q4. Shall I isolate the extension leads that go into the MPPT as well as fuse it?
Q5. Can I just turn off the MPPT and DC to DC in the viltron app if required?

I put an isolation switch between the panels and the MPPT for a couple of reasons. First, so I can isolate the panel for any maintenance without having to get to the MC4 connectors or disconnect wires. Noting the LB supply to the MPPT should be connected before solar and disconnected after. Second, so I can stop the LB being charged by solar without faffing with the app. If I’m not using the LB for a few weeks I prefer not to have it constantly topped up every time the sun comes out. I’ve done the same with the DC-DC by putting a switch in the remote plug loop (see Victron instructions). You can turn both off in the app but a switch is much quicker.

 

[Dellmassive]

Thank you Dell, was reading that this morning!
Not much info about fusing solar, but think 4mm cable will be fine for my 185w panel.

4mm will be ok for 200w, that would be max 24v/12A and below.( I run my 530w panel on a 4mm cable)

No need to fuse such lower power panels and the cant generate enough power to burn out the cable.

Isolator can be added if needs be. As above.

It's normally only the people that use combined dc-dc/MPPT units that need it.

Or lithium battery people that want to stop chRhe in winter cold temps.

But if you use a decent MPPT, ie a victron 75/15, you can switch of charging via the APP anyway so no switch needed. (Low temp. Charge protection needs an additional Victron temp sensor)

..

 

[Freshtrax]

Brilliant, thanks Del. Would you still fuse the MPTT to leisure battery cable though?

 

[Sim60]

yes - fuse at the leisure battery end. You want to protect against the leisure battery shorting to ground if the cable gets damaged etc.

 

[Dellmassive]

Brilliant, thanks Del. Would you still fuse the MPTT to leisure battery cable though?

Yes... All battery connections must be fused.