Electrics from scratch - Advice/Suggestions

[RedFrame]

So, after all the helpful information provided regarding the B2B charger I've put together the proposed wiring diagram for our new van below. It'd be great if all you knowledgeable folk would let me know if I've missed anything, anything that is not necessarily needed but would be nice, or there's something that is seriously wrong with the plan. As in the title, it's a blank canvass, 2018 style Merc sprinter LWB, I'm limited to 3 x 140w on top due to space and roof vents and they're wired in Series.

Thanks in advance for your input!

Cheers
Red.

 

[68c]

Hi, what are the black lines from the L and R 240v sockets to the battery charger and inverter? 240v feeds? Please ensure it is not possible to operate the inverter when EHU is live. Do not rely on 'never doing it'.

 

[RedFrame]

Hi, what are the black lines from the L and R 240v sockets to the battery charger and inverter? 240v feeds? Please ensure it is not possible to operate the inverter when EHU is live. Do not rely on 'never doing it'.

They are standard 240v cables with plugs on. The inverter "senses" 240v and operates as a "pass through" when on EHU, and I only want the 240v charger to operate when on EHU. (hope that makes sense).

Cheers
Red.

 

[autorouter]

Your diagram is similar in many ways to the setup have in my MH. There are two points I think are worth discussing.

I have a Victron Multiplus-2 3000 inverter/charger, which takes care of a lot of the interconnections and switching automatically, and adds some real benefits too when on EHU, especially low-amp EHU. It is a well-thought-out system.

The other point is possibly more problematic. You show 600Ah of battery, and a 3000W inverter. That means a current of 250A. But you'll probably find that all your actual 12V devices (water pump, fridge control, heater control, lights etc) won't add up to much more than 200W, possibly 300W.

Because of that I decided to use a 48V battery bank, which immediately cuts the amps required from 250A to 250/4 = 63A, a very much more reasonable figure. I got a Sterling 48V B2B, and a Victron Multiplus-2 3000 48V inverter charger. The solar controller you have listed (Victron 100/30) is about the only Victron controller that won't take 48V, all the others are fine with 12V to 48V batteries. You'd need the panels in series to get the voltage for 48V batteries, but your panels are wired in series in your diagram anyway.

I kept my 100Ah 12V lead-acid for powering the 12V habitation fusebox, and it charges by the normal split charge relay when driving, and a 15A Victron IP65 charger if I need to charge it when on EHU. If it gives up I might go for a small 12V lithium battery. I could have kept the original built-in 12V charger, but for some reason it failed (crackling and smoking) so I disconnected it. The Victron charger will do lithium batteries if I change.

I run a small kettle, microwave and rice cooker from the 240V side, and am thinking of adding more appliances. With the Victron 'Power Assist', I can run all three, plus one element of the water heater, at the same time without tripping a 6A hookup post.

Sorry to mess up your plans just when you've got it sorted, but it's a lot easier to change at this stage than to retrofit.

 

[Just smiffy]

I saved this the other day when I was investigating the same, similar to yours…

^{_{Subscribers  do not see these advertisements}}

 

[RedFrame]

Your diagram is similar in many ways to the setup have in my MH. There are two points I think are worth discussing. [....]

The other point is possibly more problematic. You show 600Ah of battery, and a 3000W inverter. That means a current of 250A. But you'll probably find that all your actual 12V devices (water pump, fridge control, heater control, lights etc) won't add up to much more than 200W, possibly 300W.

I don't I understand your ref to the 12v draw and how that relates to the 240V side, if you can explain that would be great!

The max draw on the 3000w Inverter will be the 2000w water heater running for max 17min.... >600mm long 35mm2 cables between the batteries and inverter, not sure if that would make you more comfortable?

Because of that I decided to use a 48V battery bank, which immediately cuts the amps required from 250A to 250/4 = 63A, a very much more reasonable figure. I got a Sterling 48V B2B, and a Victron Multiplus-2 3000 48V inverter charger. The solar controller you have listed (Victron 100/30) is about the only Victron controller that won't take 48V, all the others are fine with 12V to 48V batteries. You'd need the panels in series to get the voltage for 48V batteries, but your panels are wired in series in your diagram anyway. [....]

I understand what you're saying in terms of dropping the Amps for the Inverter by aligning the Batteries in Series to 48V, but I would like to take advantage of the 12V/180A Alternator that is fitted to "Groot", the downside of loosing that into a 600Ah Lithium Battery bank would be massive, considering we rarely stay in one place for more than 2 days...

Sorry to mess up your plans just when you've got it sorted, but it's a lot easier to change at this stage than to retrofit.

Not at all, as you say it's soooo much easier to change in the planning stage.

I can only see out of one window, I need to see out of ALL windows, and only other member's views/experiences/knowledge will allow me to do that..

Cheers
Red

 

[autorouter]

An inverter changes 12v power into 240V power. Power (watts) = volts x amps.
3000W = 240V x 12.5A, or 12V x 250A, or 48V x 62.5A. So to get 3000W from the inverter, you need to put in 250A at 12V.

250A is a serious amperage, requiring hosepipe-sized copper cables. Not impossible, but not necessary either.

The figures for 2000W are the same pattern.
2000W = 240V x 8.3A, or 12V x 167A, or 48V x 41.7A.

In terms of a B2B charger, I have a Sterling 48V B2B. It takes in 70A at 12V from the alternator, and pushes out 17.5A at 48V to charge the 48V lithiums. So with this you could use your 180A alternator. That Sterling 12V/48V 70A B2B was the only one I could find, maybe others are now available, I don't know.

 

[autorouter]

Regardless of the 12v/48v question, it's worth looking at the Multiplus inverter/charger. Most inverters can't synchronise with the hookup mains, so it's either/or, inverter or hookup, not both. The Multiplus synchronises with the hookup mains, with several advantages. Especially if the hookup has a low amps limit, like 6A, which you find on many rural sites.

If the load demands more than the set limit, first the charger is dialled down to keep the draw from the hookup post below the limit.

If the load is more than the set limit, the inverter fires up and makes up the difference, working in synchronisation with the hookup mains. For a 2000W inverter (8.3A), that means you can use 6A + 8.3A = 14.3A from a 6A hookup post. All this happens automatically. When the load drops, the charger goes back to charging the batteries, again automatically.

And of course when there's no hookup available, you've still got a 2000W inverter running from the batteries.

It depends a lot on how much of the time you will have EHU available. If you're always wild camping it's not a big advantage, but it's great on sites and aires with low amps limits

 

[RedFrame]

Thanks autorouter , just one, perhaps stupid, question....

I've never "stepped down" from 48v to 12v, what would you use/recommend ....?

Cheers
Red.

 

[Revolvor]

A purely academic question ... If you have 4x 12v batteries in Series to produce 48v, would it still be possible to run 12v loads by just connecting to the various 12v batteries? I realise that each 12v load would have a different "earth" so wiring would be a nightmare.

^{_{Subscribers  do not see these advertisements}}

 

[Raul]

A purely academic question ... If you have 4x 12v batteries in Series to produce 48v, would it still be possible to run 12v loads by just connecting to the various 12v batteries? I realise that each 12v load would have a different "earth" so wiring would be a nightmare.

Worse think you could do, unbalance the hole bank. There are plenty 48-12 converters for 12v loads.

 

[Revolvor]

Worse think you could do, unbalance the hole bank. There are plenty 48-12 converters for 12v loads.

Thanks - I thought it was a stupid question, and that's probably the answer I expected!

 

[Raul]

Back in the day I wanted to go 24v on the van as I had nothing bought. The 48v is even better but it needs modular bank or rack modules. After comparing various advantages I stayed at 12v in the van. The only cabling that is extra was 1,5m cut in half for the inverter 70mm2.

In your case with two batteries 48v won’t work. The only thing I would change to your design is having a DC distribution like victron power in and linx, so you can fuse each battery along with charging sources and inverter. Much better on a buss than in line.
I have a large 48v system on the house, 8,8kw and would not advise 48v on a sprinter. It will be allot more money, for same results, less efficiency on 12vdc loads, but better on 230v loads. On the van you need to put back in fast, not as much solar as on a static, so your 230v will be as in when is plenty, then ration to have enough for 12v loads. We had our set up for over 3 years and I can surely say a 24v, let alone a 48v, would not helped us at all. In fact many things run mostly without inverter, meaning a 80-85% efficiency, from drop down DC. That’s worse than 230v conversion from 12-230v. This is my opinion.

 

[Ditcha]

So, after all the helpful information provided regarding the B2B charger I've put together the proposed wiring diagram for our new van below. It'd be great if all you knowledgeable folk would let me know if I've missed anything, anything that is not necessarily needed but would be nice, or there's something that is seriously wrong with the plan. As in the title, it's a blank canvass, 2018 style Merc sprinter LWB, I'm limited to 3 x 140w on top due to space and roof vents and they're wired in Series.

View attachment 655197
Thanks in advance for your input!

Cheers
Red.

Red Good Facebook page here from roamer batteries some good info a schematics you might have already seen it.

Log in to Facebook

Log in to Facebook to start sharing and connecting with your friends, family and people you know.

www.facebook.com

 

[paddymcc]

You have a couple of breakers in the system. There are some very poor quality ones around that have failed and melted potentially causing a fire. An alternative is to simply used an in line fuse from the panels to the solar controller. I have this so I can pull it to isolate the panels when working on the system.

^{_{Subscribers  do not see these advertisements}}

 

[autorouter]

I've never "stepped down" from 48v to 12v, what would you use/recommend ....?

Actually, I've never done it either. I bought a small 48-to12V DC-DC converter, big enough to power all the habitation loads. But I have a 12V 100Ah leisure battery that charges from a split charge relay, and a mains charger powered by EHU, or even the inverter if necessary. I've never got round to fitting the 48V converter.

 

[Itsmcb]

Red Good Facebook page here from roamer batteries some good info a schematics you might have already seen it.

Log in to Facebook

Log in to Facebook to start sharing and connecting with your friends, family and people you know.

www.facebook.com

This is not a criticism of Steve or roamer batteries but I used to be a member of that group, there are some incredibly poorly informed posters and plenty of bad if not actually dangerous advice being given along with some great but totally over the top advice. Some of the photos of van installs wouldn't look out of place in an industrial setting, the cost in both time and equipment must be astronomical.

 

[Ditcha]

This is not a criticism of Steve or roamer batteries but I used to be a member of that group, there are some incredibly poorly informed posters and plenty of bad if not actually dangerous advice being given along with some great but totally over the top advice. Some of the photos of van installs wouldn't look out of place in an industrial setting, the cost in both time and equipment must be astronomical.

Same as most forums/groups you have to be able to pick the wheat from the chaff.

 

[Lenny HB]

I'm bit late to the party.
If sticking with 12v which I probably would with only one high load.

I would wire the solar panels in parallel always best on a camper to avoid total loss of power when there is some shade.

I think a 120 amp B2B is a bit OTT also I'm not a fan of Sterling products, Votronic do some nice B2B's there is a 90 amp one where the output is switchable to different outputs between 30 amps to 90 amps.

The inverter you have chosen is a cheapish one OK for your use but if you want to run any sensitive electronics I would fit a decent one like a Victron.

The Multiplus mentioned by autorouter is good if you are using EHU a lot, especially with low amperage outlets but if mainly off grid a bit of an unnecessary expense.

I agree with the comments about 12v circuit breakers being unreliable.

You don't appear to have made any provision for starter battery charging have a look at this unit, it tends to work better with Lithium than other units.

Ablemail AMT-12 Battery Maintainer – Wildebus

www.wildebus.com