Electrics self-build help…

[Freshtrax]

Hi, I’m buying a SWB T6 very soon and converting to a U shape layout.

In preparation I’ve been researching all the providers and costs for pop tops, windows, carpeting, sound deadening etc. I’ll pay for a pop top done but do the rest myself with a friend.

Looking at electrics, it seems silly NOT to wire up for solar, mains and 12v, but I have some questions that link to cost… I’ll try and keep it logical!

1. I’ve looked at pre wired boards from Rayne. Cheaper to course the components and wiring and do it myself? Much in it?

2. For the odd bit of off grid (if we can’t get an electric pitch), what size solar panel for weekends away and is flexible better for pop tops? Would only really be powering 12v lights, fridge, diesel heater and phone charger etc. Will be going lithium battery too. Might take air fryer or something for an awning for longer trips.

3. Is the cost of a victim shunt worth it to monitor the battery, when an Ecoworthy battery has Bluetooth built in? Are there any other monitoring solutions, ideally to a screen in the van? I’d like to see charge state, what capacity is left and what load is being used. If so, do all components need to be victron?

4. It seems cheaper to buy a Ctek DC-DC with solar charging built in than buying 2 x victron units right? If so, why don’t more people do this and save money?

5. Anyone done all this on a U shape? Battery and DC-DC under the driver seat, 240 in the U shape and solar either under the drivers seat (Ctek) or behind the kitchen?

Sorry for the long post, just want to get it right without wasting money on things we don’t need. This will be used for the odd weekend away spring to autumn, possibly the odd night in winter, and the odd week away maybe in Europe.

Thank you.

 

[Sim60]

Ctek is ok - I used one for 4 years before upgrading my system this year.
It has a few limitations:-

Maximum Open-circuit voltage for solar input that it supports is 23V - many panels exceed this.

20A max charging current - and gets hot if it does this for extended periods.

Not ideal lithium charging profile - it’s fine, but stops charging once the leisure battery is full, then only restarts when battery discharges to 13.3V - see some of Dellmassive’s posts on here.

I only changed because I went for Fogstar 230Ah seat base battery and want more charge current.

(Want to buy a second-hand Ctek?)

Simon

 

[Sim60]

another plus is it can provide charge pulses back to the Starter battery from solar under the right circumstances.

 

[Sim60]

For the odd bit of off grid (if we can’t get an electric pitch), what size solar panel for weekends away and is flexible better for pop tops? Would only really be powering 12v lights, fridge, diesel heater and phone charger etc. Will be going lithium battery too. Might take air fryer or something for an awning for longer trips.

Air fryer is a whole new level compared to your other loads you’ve mentioned.
Look at what size inverter you’d need and use the search function to look at what you need to do / mostly around wire gauge and fuses. But check h the discharge rate of the battery you’re thinking of fitting

Simon

 

[roadtripper]

Think carefully if you actually need the mains - these days a solid LiFePo install and staying 12v/USB may be all you need.

Any mains device that is a heater is, as @Sim60 has already pointed out, a very different thing and a very significant load indeed. It's not impossible to do (several forum members have) but it will dominate the cost of the install if you want to run those loads off grid. Consider how often you will need to run power hungry 240v devices off grid before you invest in the four figure install.

As an observation the brands/devices you are picking are competent but I would say they are the cheapest possible without being a risk. Given the amount of time and energy you will invest in the conversion initially more expensive devices may be better value on the long term. Especially if this is your first camper and those occasional weekends away turn into longer trips once you find you enjoy it.

 

[ginkster]

Do you know your usage exactly from previous experience or is this a new adventure? What do you need/want the EHU for and do you really need the air fryer?

If you don’t need 240v I’d recommend not bothering with the EHU element and invest in a better off-grid solution. Being free of EHU massively increases flexibility and saves money at sites and reduces complexity of the build. A 12v only system with DC-DC and solar will do everything you ask, bar the air fryer. If that is for the awning and only for use on a site with EHU then you could run that off a simple lead direct into the awning. If you want to use it off-grid then you will need an inverter with significant added cost and complexity.

I upgrade an existing system to a 105ah Fogstar Drift (under the single passenger seat) with a Victron DC-DC and a 200w solar panel with a Victron MPPT. I’ve not used EHU since and not bothered to fit the Victron mains charger I bought (cables in place but charger in the house!). Solar has covered everything for me (same loads you mention) to the point that I have only used the DC-DC on a couple of occasions. We did just over 2 weeks in NW Scotland this May and a few 4 night weekends over the last year or so on solar only. The battery will drop to about 85% by the morning but has always been fully topped up the next day regardless of weather.

So, I’d say consider carefully your usage. Do a power audit so you know how much power you need and how it will be replaced. I’d then get the off-grid bit right so you can camp anywhere. Adding EHU if you find you really need it could be done later. I’d also buy my own stuff rather than a Rayne kit.

Edit - Roadtripper beat me to it!!

 

[Stay Frosty]

However... if you really will miss that air fryer and like myself need to take your hair straightener and John Corby trouser press on holiday or like @Drive Wayne your SDS drill then adding a 2kw inverter gives you 230Vac as well as 12Vdc.
I've gone for Renogy gear as it's cheaper in general than Victron and can be more versatile.
Their DCC50S is a 50A DC to DC charger with a combined mppt charger giving up to 50A output from a combination of your alternator and solar, it can be throttled back to say 30A output so everything is a bit calmer and on the latest version is tolerant of an higher input voltage from the solar of up to 50 Vdc which allows for series parallel combinations of multiple panels.
From memory I paid about £200 for their 2kw inverter, we're using a Roamer 230Ah seatbase battery but if you're doing your own conversion you might want to look at some of the outrageous value for money lithium iron phosphate batteries out there now, Renogy currently have a 300Ah mini core battery at £539 on offer, bonkers value.
As for phone app displays I'm an old fart (66) that likes to see a readout that doesn't rely on me having grown up with smart phones, we've got a Renogy smart shunt and display that tells you whether power is going into or out of the battery and how much in either case, plug our travel kettle or two slice toaster in and you can marvel at nearly 80A at 12.5V coming out of the battery just for two cups of tea.

 

[Drive Wayne]

Our recent purchase of a Bluetti AC180 power station has pushed my 2000 watt inverter into semi retirement! The coffee machine, toaster and occasional use Airfryer are powered by it, rather than the Roamer and inverter. Also a solar suitcase plugged into the Bluetti to keep it happy. A 270 watt Victron rigid panel on the poptop too.
The in-house Roamer is still utilized for 2 compressor fridges, wifeys Dyson hairdryer and alsorts of whatever we need.
Systems work well together, 320Ah total power availability is more than we need, especially when the sun shines!

 

[Freshtrax]

Ctek is ok - I used one for 4 years before upgrading my system this year.
It has a few limitations:-

Maximum Open-circuit voltage for solar input that it supports is 23V - many panels exceed this.

20A max charging current - and gets hot if it does this for extended periods.

Not ideal lithium charging profile - it’s fine, but stops charging once the leisure battery is full, then only restarts when battery discharges to 13.3V - see some of Dellmassive’s posts on here.

I only changed because I went for Fogstar 230Ah seat base battery and want more charge current.

(Want to buy a second-hand Ctek?)

Simon

All great info. Thanks for the replies

 

[Freshtrax]

Do you know your usage exactly from previous experience or is this a new adventure? What do you need/want the EHU for and do you really need the air fryer?

If you don’t need 240v I’d recommend not bothering with the EHU element and invest in a better off-grid solution. Being free of EHU massively increases flexibility and saves money at sites and reduces complexity of the build. A 12v only system with DC-DC and solar will do everything you ask, bar the air fryer. If that is for the awning and only for use on a site with EHU then you could run that off a simple lead direct into the awning. If you want to use it off-grid then you will need an inverter with significant added cost and complexity.

I upgrade an existing system to a 105ah Fogstar Drift (under the single passenger seat) with a Victron DC-DC and a 200w solar panel with a Victron MPPT. I’ve not used EHU since and not bothered to fit the Victron mains charger I bought (cables in place but charger in the house!). Solar has covered everything for me (same loads you mention) to the point that I have only used the DC-DC on a couple of occasions. We did just over 2 weeks in NW Scotland this May and a few 4 night weekends over the last year or so on solar only. The battery will drop to about 85% by the morning but has always been fully topped up the next day regardless of weather.

So, I’d say consider carefully your usage. Do a power audit so you know how much power you need and how it will be replaced. I’d then get the off-grid bit right so you can camp anywhere. Adding EHU if you find you really need it could be done later. I’d also buy my own stuff rather than a Rayne kit.

Edit - Roadtripper beat me to it!!

That’s great info, much appreciated.

 

[Freshtrax]

Thank you all for the really useful replies, much appreciated!
For clarity, the air fryer thing was just an example. The Mrs thinks that she’ll only ever stay on sites with electric hookup, but that’s based on old trips when we used to tent camp and needed power to an electric cool box and light, kettle etc.
Now I’ve explained to her what actually works from 12v like the fridge, heater etc. she’s less wedded to the “must be hooked up” idea.

I did consider a camping EHU with breakers might be a better solution for longer trips with an awning.

Great info from ginkster about how effective just a 105ah lithium can be with solar.
Given me plenty to think about.

 

[Bigsidavies]

We have LWB with u-shaped seating.
100Ah Renogy lifepo4 and ctek 250se under the driver's seat.
along with busbars and other bits of wiring.
Victron MPPT in roof void at rear of pop top.
Victron 15A AC-DC and consumer unit on rear of kitchen unit as we have a twin slider.
12V fuse panel on rear of kitchen units and Remogy One M1 control panel on splashback next to the diesel heater control.
EHU inlet under bonnet next to battery.
100W rigid solar panel on roof bars.

We virtually never use EHU, (Thursday being an exception so I could charge my e-bike).
I used to use the ctek for solar and dc-dc until I had a power issue with it at the start of a 10 week spain trip. There is no redundancy. So the solar panel gives no input if the dc-dc fails, so we were goosed for any means of recharging the battery so had to start looking out for EHU evry three or four days. Hence bought the Victron MPPT in Spain and fitted it whilst on the trip. I'd now never use a combined unit, even though I fixed the CTEK (failed external relay) and it's still in use. Also the max charge is 20Amps. So on a sunny day you could be getting 7A from the solar and on a short drive you'll still only get 20Amps not the 27 being generated. Also I never used to see more than about 5Amps solar max going into the battery from the CTEK. I now get 7A on a good day from the Victron. These differences are signifcant if you are off grid and there are only a few hours of good sunlight. 3 hours of bright direct sun will put back a day's battery useage for us. I was getting 3.9Amps on Friday morning at 0830 in North Yorkshire!
Your usage is pretty much what we have-fridge, lights, phones, diesel heater etc. We don't hve a shunt, I'm happy with the reading from the battery BMS.

 

[Freshtrax]

Thanks Bigsidavies, great info. Sounds like victron is the better way to go. Silly question, what’s the battery BMS? What info does it give?

 

[Stay Frosty]

Battery Management System, blue tooth link to your phone from the battery to give State Of Charge and show charging history in realtime among others, much more information than you get from the smart shunt display but you need your phone handy and to be honest a lot of it is just a confusing blizzard of info at times.
I have one bit of Victron kit and that's their 30A mains charger, great kit but not the only name in leisure power, like I said earlier I'm a bit of a Renogy fan boy though.

 

[Bigsidavies]

BMS is not always as accurate as the smart shunt over time. The BMS doesn’t apparently notice small power drains. My van sat for 8 weeks and the Leisure Battery had gone flat but the BMS showed it to be nearly fully charged.
Over short periods I’m happy to rely on the BMS though and I normally use my van every few days, the 8 week park up was due to the van being poorly over Christmas/new year.

 

[TeeCeeJay]

@Freshtrax just to add to this for you.
We have lights, fridge, no heater, a 12v Cig lighter socket, no permanent USBs & No 240 set up because we have a small bluetti power bank for laptop/phones etc if required - which we recharge off the LB. Solar is a 200w semi flex panel and a renogy 50a DCDC which will will top up the engine battery when the LB is full. All running off a 100ah lithium battery and we've never even been close to 50% battery drain even after a fortnight tour. If we wanted a coffee machine or more power hungry devices, I would change our power bank first before considering 240v. Like you we are ex tenters, but never had power doing that, so a working fridge is absolutely luxury for us!