My electrical help thread

devonian

Member
Joined
Apr 5, 2020
So finally I have nearly all the electrical supplies I need (I think) and I popped down to screwfix yesterday to get a decent wire cutter crimper (a CK one) and a multimeter so I can now begin to attack this job...but... there is a problem.. I haven't got a clue what I'm doing and I've never done any electrical work before so this is why I've created this thread so if anyone is kind enough to answer my hopefully not too many questions it would be very much appreciated.

First up my diesel heater live wire has a 15 amp fuse already attached should I still have another one when I run it to my blade fuse box? Or should I cut it off an just have the fuse on the fuse box for it? I am going to have to cut the wire anyway as the 'ring' terminal on the end is too big for to fit into the fuse box. Picture below. Thinking about it my fantastic vent is fused as well so same question there really.

Also I found this blue wire at my workplace not exactly sure on the thickness but its at least 6mm and it is stranded do you think it will do for feeding my compressor fridge? I shall be getting a Vitrifrigo C39i. Sorry about lack of focus.
 

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WildVan

New Member
Joined
May 9, 2020
Hi,
Heater - if you connect it to your fuse box cut it off. I’d suggest it had its own fuse so that if it blows you know it is the heater that did it.
My own heater is connected directly to my leisure battery, so I kept the fuse. This way my heater does not need reprogramming ( timer) and does not go through it’s test routine every time I switch the van power back on.

6mm cable will be fine for the fridge. Either 6mm2 or 6mm diameter, you didn’t specify but both are ample. When you see the cable you will wire into on the fridge, yours is beefier. The point being with a 12v system you want to minimise power lose over longer runs. Thicker cable minimises power loss. Obviously make sure you label + and - as they are not coloured red and black.

good luck.
 

Littleoldman

Active Member
Joined
Jun 3, 2019
I was in the same position as you a few months ago ( nearer 8 months but I’m not counting) Learned all I know about 12v from Greg Virgo and Gadget John on YouTube. Can’t recommend them enough. As a student 50 years ago all the information I needed was found in books, but watching a video is so much easier.
 

devonian

Member
Joined
Apr 5, 2020
I was in the same position as you a few months ago ( nearer 8 months but I’m not counting) Learned all I know about 12v from Greg Virgo and Gadget John on YouTube. Can’t recommend them enough. As a student 50 years ago all the information I needed was found in books, but watching a video is so much easier.
Thanks I will check both out.

Anyone know what I am meant to do in this situation my 6mm2 wire for my compressor fridge appears to be too large to fit into this ring terminal and this is the only size ring terminal thats small enough in my selection box to fit into the fuse box. Ideas?
 

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david.c.hall

Active Member
Joined
May 16, 2016
Location
Irnham, South Lincolnshire
The important thing to remember is that fuses are mainly there to protect the cable.
So you can leave the one close to the appliance if it's easier but you do need to put a fuse close to the point that it connects to the power supply, be it fuse box or the battery.
David
 

devonian

Member
Joined
Apr 5, 2020
The important thing to remember is that fuses are mainly there to protect the cable.
So you can leave the one close to the appliance if it's easier but you do need to put a fuse close to the point that it connects to the power supply, be it fuse box or the battery.
David
I've cut the fuse off now that was on the heater wire, the wire was so long anyway it needed to be trimmed and I've actually repurposed that trimmed wire on another totally different project so I'm already using my new skills.

Regrading linking batteries in parallel, I have ordered some 35mm2 wire and terminals for that but what is the best size wire for linking the batteries to my fuse box? 35mm2 again or 16mm2 like I am using on my votronic battery to battery charger?

Also grounding the batteries to the chassis is 16mm2 acceptable or 35mm2 better?
 
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david.c.hall

Active Member
Joined
May 16, 2016
Location
Irnham, South Lincolnshire
16mm should be fine as long as the run is not to long.
Grounding to chassis is fine. Although sometimes you will finish up using more cable depending on your layout.
On my van this was the case so I used cable.
David
 

devonian

Member
Joined
Apr 5, 2020
I shall probably use 35mm2 for linking the two leisure batteries and the fuse box and 16mm2 for the battery grounding but I shall see once the cable arrives this weekend. I just hope I have everything I need now and don't need to order anything else from 12voltplanet.
 

BigStevie

Active Member
Joined
May 17, 2017
Location
Highlands
Haha! If you’ve got everything in one go, buy a lottery ticket! However well I’ve planned, I’ve always ended up having missed something. There again, it could be my advancing years.... who am I?......
 

devonian

Member
Joined
Apr 5, 2020
You were right I had the incorrect fuse holder for a 35mm2 cable (going to the fuse box) so I've ditched that and had to order a new fuse (I went for 70a) and holder a midi one that will fit a 16mm2 cable. Problem is 12voltplanet has disabled their checkout presumably because they are being overwhelmed by demand and the lack of staff so I think I'll have to move onto to something else probably installing the votronic b2b charger as I know have all the stuff for it.

Question regarding doing electrical work with car batteries and leisure batteries: Whats the chances of electrocution or accidents when working here? Is there a specific action thats dangerous and will cause accidents? Thanks
 

Littleoldman

Active Member
Joined
Jun 3, 2019
I’m new to 12v but if you don’t connect your batteries until you finish everything can’t see a reason that you would hurt yourself. Use a multi meter to check your cables, and I was given this tip by a friend ( back in the day before Covid when we had friends) use a small lamp with 2 leads connect this to one side of a cable you have run and a small 9v battery on the other and if it lights up you have identified the cable. For cable sizes Greg Virgoe has a new video which is clear and helpful. For me this was going to be the most daunting part of the build but it turned out to be OK. Good luck.
 

BigStevie

Active Member
Joined
May 17, 2017
Location
Highlands
I couldn’t agree more. A bit of old school testing to make sure everything is as it should be, safest way. Someone gave me a mains to 12v dc bench transformer years ago, I test every cable with a bulb, simple but sure.
 

devonian

Member
Joined
Apr 5, 2020
Has anyone got any experience with solar panel installation I have one already mounted on the roof but have yet to wire it up, I just want to check with someone about this. I have a 4 metres of black and red pv 6mm2 cable pre crimped with mc4 connectors. They have connectors on both ends do I just cut the connectors off on one end run the red through a 60 amp fuse and then into my solar charge controller? Does that sound about right. Sorry the instructions are in Chinglish or not very plain english anyway.
 

devonian

Member
Joined
Apr 5, 2020
You don't need a fuse between the solar panel and the controller

David
Do I need a breaker then or anything? This diagram here (half way down the page) says I need a breaker https://www.amazon.co.uk/gp/product/B07S7931LG?pf_rd_r=26ECT2JR1A6KZ2DSY3G3&pf_rd_p=e632fea2-678f-4848-9a97-bcecda59cb4e

Also does it matter what size the pv cable is as I only have 6mm2 going to a 40amp mppt charge controller? (I guess I need to use 16mm2 from the charge controller to the battery.)
 

david.c.hall

Active Member
Joined
May 16, 2016
Location
Irnham, South Lincolnshire
Although the circuit doesn't require a fuse it may be easier to be able to isolate it Roadrunner suggests., rather than just disconnecting at the controller.
This is because you must always connect the battery to the controller before the solar for it to work correctly.
Have you bought the controller in the link? I only ask because if not I would suggest that you consider a Victron controller
Personally I would use a switch if I wanted the facility as fuses introduce resistance into the circuit.
David
 
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