Invertor and leisure battery advice for new motorhome (1 Viewer)

[JerryD]

I bought a motorhome recently, Rimor Superbrig 698 tc and am loving it! Only issue is that there is no invertor and only one 12 watt charging point.

I want to use the motorhome off grid for short trips of one to two nights max and to be able to use 240 volt appliances sparingly when I do. One of the things I would like to have the option of powering is the air conditioning unit which I believe has a very high wattage.

Thinking of getting 300 to 400ah lithium ion leisure battery (high cost, low weight, can fully depleted) and a 2000 watt inverter.

The motorhome has a small solar panel that came with it. I'd probably need to change the solar panel wiring to make it work with leisure battery etc.


Does this make sense as a plan? Has anyone done the same thing? Any advice appreciated

Cheers

 

[Tombola]

Yes, but 400ah dep on how much you use the air con. YOu need more solar...get as much solar as you can fit, 600 minimum if using air con, good B2b Charger.
Solar wiring to mppt - batt use 6mm,
My attitude is if you use plenty power and need it topping up then lithium if you can afford it.

the main point here is the air con, if you dont have that, all the above is pointless, if you use 240v sparingly

 

[Abacist]

Check your van in-built charger has a lithium charging profile!

 

[JerryD]

Cheers Tombola, I don't plan to use air con all that much, I live in Scotland, so not wanting to base the whole upgrade around it. However on the rare occasion we do get a nice got sunny day, and if I manage to venture further, Aircon could be nice for a comfortable night so like the idea of keeping options open.

Not loads of space for solar panels ironically because of the space Aircon takes up, plus it's an overcab bed.


Was thinking that even without Aircon, going 300 plus amps would be beneficial make life stress free for power supply when on short trips. Also looking to power a music system.

So thinking lithium ion and powerful inverter, look into increasing solar panel capacity a bit more, occasional air con if got and then be able to relatively carefree with the 240 if it's for a one or 2 day trip and not using Aircon, if that makes sense?

And thanks Abacist I'll look into the charger. I probably will need to change it.

 

[Tombola]

Cheers Tombola, I don't plan to use air con all that much, I live in Scotland, so not wanting to base the whole upgrade around it. However on the rare occasion we do get a nice got sunny day, and if I manage to venture further, Aircon could be nice for a comfortable night so like the idea of keeping options open.

Not loads of space for solar panels ironically because of the space Aircon takes up, plus it's an overcab bed.


Was thinking that even without Aircon, going 300 plus amps would be beneficial make life stress free for power supply when on short trips. Also looking to power a music system.

So thinking lithium ion and powerful inverter, look into increasing solar panel capacity a bit more, occasional air con if got and then be able to relatively carefree with the 240 if it's for a one or 2 day trip and not using Aircon, if that makes sense?

And thanks Abacist I'll look into the charger. I probably will need to change it.

Yes, makes sense to me.
So the air con is already fitted.
So if you say use of that is to be sparce then Id say similar to my set up.
400 of lithium (2 x 200 in case one goes tits) 600 solar and a decent b2b. Is it overkill, yes lots of the time I could do with 200ah or less, but I need it to run medical gear for my wife , so I like the extra when needed.
Most of the time I have loads spare, but am glad its there when required, and if you do use your air con , its gonna be sunny isnt it? then plenty solar will help.

end of the day...if you have the ££ then lithium batteries, b2b, decnt inverter and solar are a winner. Pulling onto sites and not even needing EHU and plugging anything in no matter where you are is gold.

be very interested to see what you do and how you get on.
there are plenty lithium 3 stage chargers , Victron bluesmart is a good one

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[JerryD]

Cheers Tombola that's helpful. Will def let u know how I get on. What lithium ion batteries did you get? Been looking at lifepo4 ones which are apparently the best but wondering if necessary

 

[JerryD]

Cheers Tombola that's helpful. Will def let u know how I get on. What lithium ion batteries did you get? Been looking at lifepo4 ones which are apparently the best but wondering if necessary

 

[bigtwin]

Cheers Tombola that's helpful. Will def let u know how I get on. What lithium ion batteries did you get? Been looking at lifepo4 ones which are apparently the best but wondering if necessary

LiFePo4 are the only lithium variant you should consider.

I can recommend Life Batteries.

Ian

 

[peterc10]

LiFePo4 are the only suitable ones. We used KS batteries who advertise here and give a MHF discount. But there is no point in having a large battery if you do not have a way of refilling it. So you will need a good B2B for charging on the move and more solar panels for when you are stationary.

Can't really understand the need for air con in Scotland. We have managed in Spain, Portugal and Italy without it. Do you have it in your home? If not why in your motorhome? Just open the windows if you get hot. Most motorhome windows have flyscreens.

 

[grasscutter]

For the odd occasions you are planning using air con you might want to consider a fan. Far less current draw.

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[Jake Royd]

For the odd occasions you are planning using air con you might want to consider a fan. Far less current draw.

I found my 240v air conditioning to be very noisy and not all that effective.
It died this year , so I replaced it with a Maxxair fan.
Much better and of course runs off EHU.
Surprisingly it also improved the motorhomes handling. It's circa 50Kg high up.
I have 200w of solar a 100Ah battery and lots of usb's. We get on fine with TV in the evening and phone charging etc when off grid.

 

[funflair]

I would be tempted to go for a 3kw inverter and then you are not so limited on choice of 240v appliances, you say one or two nights so you would be able to use an electric kettle no problem of 400ah, nothing worse than waiting for a low wattage kettle that loses heat faster than it gains so 1800-2200watts is a good compromise, do check the BMS on the LiFePO4 though as the maximum continuous amps figure might dictate what inverter size you can go for.

 

[Tombola]

KS energy 2x200ah Bluetooth app version they did/do a 10% funster discount. A few funsters have them and no problems.for me.
I'd also agree if your gonna do it go 3kw inverter. I went for the renogy one with ups auto switch

 

[Garry - June]

As Tombola above we have also installed 2x 155ah KS Energy plus a Renogy 3000w inverter, all of which is performing brilliantly .... however the crucial thing is we also have 430w roof mounted plus a further 300w of portable solar panels... it will make no difference what batteries you install if you do not have sufficient capacity to charge them and keep them charged.

 

[Wyvern]

it all depends on what 240v appliances you want to run. Our set up is 3kw inverter, 400ah, 115 watt solar and 90ah b2b.

We stay off grid for days on end and have never come close to using the batteries to their full capacity.

My view would be if you are looking for say 3/4 days off grid then I would say 200ah lithium is ample, don’t bother upping your solar and invest in a b2b charger. 60ah would be ample.

In terms of the inverter, unless you are running major appliances 2kw again is ample. Don’t bother trying to power the aircon, to do so you will need 600ah plus to run any length of time. We have aircon and used it twice in two years and this is travelling for a total of 13months in that time around the Greece and other assorted countries.

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[Garry - June]

it all depends on what 240v appliances you want to run. Our set up is 3kw inverter, 400ah, 115 watt solar and 90ah b2b.

We stay off grid for days on end and have never come close to using the batteries to their full capacity.

My view would be if you are looking for say 3/4 days off grid then I would say 200ah lithium is ample, don’t bother upping your solar and invest in a b2b charger. 60ah would be ample.

In terms of the inverter, unless you are running major appliances 2kw again is ample. Don’t bother trying to power the aircon, to do so you will need 600ah plus to run any length of time. We have aircon and used it twice in two years and this is travelling for a total of 13months in that time around the Greece and other assorted countries.

why on earth, especially as you spend so much time in the sun blessed areas of the Med would you not fit as much solar as possible and utilise that free solar ball up in the sky...by not doing so you are little more than a mobile diesel generator.. maybe by moving around every few days that suits your travel style but not making use of something that's free seems strange to me.

 

[Wyvern]

why on earth, especially as you spend so much time in the sun blessed areas of the Med would you not fit as much solar as possible and utilise that free solar ball up in the sky...by not doing so you are little more than a mobile diesel generator.. maybe by moving around every few days that suits your travel style but not making use of something that's free seems strange to me.

 

[Wyvern]

It’s not free…you have to buy a solar panel. If you are buying the other kit anyway why not use the electricity being generated by your engine….note he said that he only needed to be off grid for a few days so presumably will be moving the van…why buy more solar when it is not needed….seems a waste of money and resources to me.

 

[wfdTamar]

Jeez, that's a lot of expense just to run an Air Con on a few odd nights. The odd 240 volt appliance isn't such a big task, but AC certainly is. An appliance is usually low power for long duration (TV, E-Bike or computer charger, CPAP), or high power for short duration (hair dryer) so my thinking is you either get a Full Sine Wave (FSW) quality inverter for the former and/or a cheaper higher power inverter for the latter type stuff. A quality FSW powerful enough to do everything is expensive and has more standby loss if you're not needing the power (of course you can turn it off). An AC is high power for a long duration so you'd need heaps of battery, a big quality inverter and some way to replenish the batteries (solar and/or B2B charger).

You can likely currently run a few smaller 240 volt things (TV, chargers) with a modest inverter. However, even a CPAP machine might need extra battery capacity and charging. Given you're limited in roof space for solar, a B2B charger seems logical (also good for northern climes/out of season use). To run more serious 240 volt stuff (say 800 watts +) needs much more thought. Anything that heats or cooks. Almost everything has a more sensible gas alternative. If you were talking longer trips or full timing, then you might consider how to do it with electricity, but for occasional use it's a bit of overkill.

I hate it when people poo poo the way others want to use their motorhomes, but in this case I too have to question the plan. I'd either book into a powered site if it looks like being over your heat threshold, or try fans. Look for alternatives for any higher powered 240 volt appliances. I'd be interested to know what they are.

 

[Raul]

It’s not free…you have to buy a solar panel. If you are buying the other kit anyway why not use the electricity being generated by your engine….note he said that he only needed to be off grid for a few days so presumably will be moving the van…why buy more solar when it is not needed….seems a waste of money and resources to me.

Here is a thought,
While your 90a B2B puts demand on the alternator, the engine will require extra fuel. At 90a and 13.6v your B2B will push 1.2kw into discharged lfp. So far so good, fast charge and a couple of hrs driving you recharge couple of kWh into your battery.
The thing is, your alternator is about 40% efficient at best, 1L of diesel is about 10kwh so it will take 1/2L of diesel for 2hrs charging with 1kw from your alternator. This is fine in winter, but, in summer you can get that 2kwh from as little as 350w of solar.
My logic says, fit as much solar as you can, and make up the shortfall with the B2B only when solar is not enough. This surly is much cheaper than 1/4L diesel per kWh when the sun is up.
I appreciate we all have different needs, but, you can’t go wrong, and is no waste with solar.

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[autorouter]

And thanks Abacist I'll look into the charger. I probably will need to change it.

If you are using a lot of electric power with inverter/lithium, and not much solar, you could consider charging from an EV charging point. Most of them will do 240V charging in the same way that EHU works. In that case, a high power charger is a good idea, because it minimises the time you are connected to the charging point. A lithium battery can take quite high charge rates, and can be practically fully charged from flat in an hour or so. Many chargers like the Victron can be parallelled up to increase the charge rate if necessary.

An EV point will give you at least 3kW, which would be good for over 200A of charging. Most are at least 7kW, which would be good for over 500A at 12V.

 

[Raul]

Do you realise the hardware involved to plug a type 1 or type 2 into a 240/12v charger? Who is going to let the charging station on with a diesel Motorhome?
Also it needs coms between station and charger.

 

[autorouter]

Do you realise the hardware involved to plug a type 1 or type 2 into a 240/12v charger? Who is going to let the charging station on with a diesel Motorhome?
Also it needs coms between station and charger.

Yes, I have that set up on my MH. It's not trivial, but it's not a big deal. I mounted a 'Type 2' socket in a standard Bullfinch EHU inlet flap, with a little circuit board for the 'comms' bit. I have a manual switch that I have to press to enable the charging, but that could easily be on a 10-second timer.

The main problem is actually parking the MH near the EV points. Sometimes it's easy, plenty of clear space. Others are impossible for my 7m Hymer, but would be OK for campervans for example. I have a 10m Type 2 cable, which is better than the usual short cable.

If the charging points are busy I move on to the next ones, but more often than not I'm the only customer there.

 

[Tombola]

So plenty including Telsa have "granny charge" cables that plug in via std 3 pin plug or 16a commando socket and I guess the chunky box a couple of feet down the cable where the "socket" ends plug in controls the charge? (the bit Ive circled in the image.)

So is it not possible to just remove the type 2 connecter plug from the car end and replace with a 16a commando and plug in to the MH ? edit: and also have a type 2 socket to plug the charger into instead of a 3 pin plug end

 

[autorouter]

So plenty including Telsa have "granny charge" cables that plug in via stad 3 pin plug or 16a commando socket and I guess the chunky box a couple of feet down the cable where the "socket" ends plug in controls the charge? the bit Ive circled in the image.

So is it not possible to just remove the type 2 connecter plug from the car end and replace with a 16a commando and plug in to the MH ?

That's a solution to a different problem - how to charge an EV from a standard 13A socket. For a MH you can just use a standard EHU cable, with a 13A adapter on the end. No comms necessary.

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[Raul]

I got that, so you brought in the 230v via type 2 cable instead of conventional 16A blue’s. What good is that? Where’s the charger? Same charger that will work ok of the 16A hook up.
Am I missing something?

 

[Tombola]

That's a solution to a different problem - how to charge an EV from a standard 13A socket. For a MH you can just use a standard EHU cable, with a 13A adapter on the end. No comms necessary.

Yeah sorry, I didnt explain well and have edited the post above. I have a feeling the answer maybe no of course not...but Ill ask anyway.


Chop of the 13amp end , replace with type 2 or ccs socket female, that the ev charger can plug in to
chop off the car connector male, replace with commando
leave the box in the middle to work out the 16a charge?

No ?

 

[autorouter]

I got that, so you brought in the 230v via type 2 cable instead of conventional 16A blue’s. What good is that? Where’s the charger? Same charger that will work ok of the 16A hook up.
Am I missing something?

Yes it's the same charger. I use one of those manual generator switchover switches to go between the 16A blue inlet and the Type 2 inlet. Both go the the Multiplus 2 3000, with its 35A 48V charger, equivalent to 140A at 12V. It's only about 1700W so it doesn't stress anything.

Having the EV inlet means for example I can stop on a Tesco car park, plug in for an hour or so, do some shopping, have some lunch, and leave with the batteries much higher, if not full. Then I can stop anywhere for the night, no need to worry about EHU.

 

[autorouter]

Chop of the 13amp end , replace with type 2 or ccs socket female, that the ev charger can plug in to

Problem is, the EV charge point needs comms, which is an extra 2 wires with electronics. It won't turn on unless it thinks there's a charger connected ready to take the power. I don't think that box will have the comms in that direction, it's looking after the comms to the Electric Vehicle.

 

[peterc10]

It’s not free…you have to buy a solar panel. If you are buying the other kit anyway why not use the electricity being generated by your engine….note he said that he only needed to be off grid for a few days so presumably will be moving the van…why buy more solar when it is not needed….seems a waste of money and resources to me.

AFAIK there is no such thing as a free lunch. The higher the load on the alternator, the lower the mpg.

Our solars have long since paid for themselvds