Newbie electrical thread

[mbee123]

After purchasing a van just before lock down I'm very much stuck in the planning stage, completed the sound deadening and the majority of the insulation while waiting to get pop top and windows fitted, so need to plan cabling etc before fitting carpeted panels etc

I'm expecting to use the van for the odd night or two off the battery, anything more I would be looking at a camp site with electrical hook up

I'm very much in the keep it simple camp, requirements/rough plan below:-

240V :-
Already installed cable under bonnet ready for RCD mounted under the seat (already purchased with 16 and 6A breakers)
Feeding Leisure battery charger and 3 x sockets

12v :-
2 or 4 USB sockets to charge phones
Around 4-6 LED spot lights in addition to LED strips around the kitchen area
Fridge (probably CRX50)
Eberspacher Heater Control
Water pump for tap

As can be seen apart from the fridge (approx 1 amp/h) there's nothing too resource hungry

Would it be feasible to go with a Solar panel/charge only and not bother with a B2B charger, as there are some good deals on 150W panel kits around (£150ish), as stated anything more than a couple of days I would be looking at hook up which would charge the leisure battery (110-130Ah)

Location for equipment:-
Battery, RCD and 240V charger under drivers seat (and B2B charger if needed)
Cabling from battery to fuse box/breakout in rear wardrobe, would this need to be 16mm squared or is that a bit over the top?
From then I'd need 4mm to fridge and 1.5mm for the LED lights and 2.5 for the USB chargers, does that sound right?

Thanks for any help....

 

[T6Jay]

My previous van had a 130W solar panel with MPPT charger (MPPT is better than PWM if every drop of sunlight matters!), and this would keep us going for a long weekend (in summer), without running the van at all. We DID have a split charger though, so driving time topped up the leisure battery.

Our appliances were just like yours, but we seldom used the heater, or the water pump. Don't underestimate how much Ah the heater will use, although it draws less current than the fridge, it's ON for more of the time!

If you have a decent battery and charge it before leaving home, I would think you will be ok for two days.

However! If you have to buy an MPPT controller for the solar, why not spend a little extra and get one with DC/DC built in? I have done this on my new van.

 

[T6Jay]

Cabling from battery to fuse box/breakout in rear wardrobe, would this need to be 16mm squared or is that a bit over the top?
From then I'd need 4mm to fridge and 1.5mm for the LED lights and 2.5 for the USB chargers, does that sound right?

Don't do this! Why run a cable from front to back, then to front (fridge?) again? Volt drop is a real thing, and you only have 12-14V to start with. Put a smaller fuse near the battery for the fridge, and maybe the same for the heater. Or keep the cable runs as short as possible some other way (I will be putting my fusebox next to the fridge)

Do you have a battery protection device to cut the feed when it's discharged?

 

[mbee123]

However! If you have to buy an MPPT controller for the solar, why not spend a little extra and get one with DC/DC built in? I have done this on my new van.

Thanks for the replies, so a Ctek Dual 250SE would do this? A bit more expensive than the Sterling B2B i was looking at, but I'd prefer to have less components

Do you have a battery protection device to cut the feed when it's discharged?

Honestly didn't think about that, something like this - Victron BP65, do Victron do an all in unit (MPPT DC/DC)?

Your cabling suggestion makes sense, do my cable sizes look right? I guess i need an ignition live feed if i go with the Ctek, what size cabling would that need to be?

Thanks again...

 

[T6Jay]

Thanks for the replies, so a Ctek Dual 250SE would do this? A bit more expensive than the Sterling B2B i was looking at, but I'd prefer to have less components


Honestly didn't think about that, something like this - Victron BP65, do Victron do an all in unit (MPPT DC/DC)?

Your cabling suggestion makes sense, do my cable sizes look right? I guess i need an ignition live feed if i go with the Ctek, what size cabling would that need to be?

Thanks again...

I bought the Renogy DCC50S, it has a slightly higher solar VOC than the CTEK, and a much higher overall current rating, I think it's also cheaper (I got 10% off). I can't say how it performs yet, for obvious reasons. No doubt someone will chip in about the CTEK. I don't think victron do a combined unit. You really should read the 'how i done it' threads by Dellmassive on here.

I also used the BP65, not much to say about this really, except it can have bluetooth, and tell you the battery voltage on your phone. I also have a Victron BM702, which works out the state of charge of the battery for you, and can tell you the car battery voltage as well.

On cable sizes, you really should work it out, I made a little spreadsheet like this;



You can see the mv/a/m column shows millivolts dropped for 1A over 1M of cable, so for instance for a 5m run (and return*) with 10A and 10mm cable the drop would be;
(5+5) x 10 x 1.91 = 191mV
So 12V at the battery is now 11.8V at the fusebox, then even less at the fridge.
*the return is via the car body, and I have no idea what this is like in practice, it will depend on earthing point quality etc so I assumed it will be equivalent to using cable.

Hope that helps, I can email the spreadsheet if you want?

 

[mbee123]

Thanks again, yes I've read the dellmassive thread and got a bit lost but will re-read, the Renogy is a bit cheaper but seems a bit less common, I'll wait and see if more opinions come in

The table is useful thanks, i'll do some research