How much is too much battery capacity?

[chrisandbev]

hi,
we have 630ah and also another 200ah that came with the van, we use the 630ah for all the extra electrical extras, ie hair dryer,electric kettle, induction hob and air fryer by doing it the way we have it set up we do not have to worry about using as much power as we want.
my main problem is the starter battery needs extra charging when we park up for more than 4 days.

 

[JockandRita]

my main problem is the starter battery needs extra charging when we park up for more than 4 days.

A Vanbitz Battery Master or a CBE Battery Manager will solve that problem, if cab battery charging is not already available via solar charging.

Cheers,

Jock.

 

[Nirvanauk]

I have a mate who is from Texas.
His favourite saying is:
“ what’s biggest is best and too much ain’t enough!”

 

[cyberyacht]

I have a mate who is from Texas.
His favourite saying is:
“ what’s biggest is best and too much ain’t enough!”

"Well, he would say that wouldn't he"- Mandy Rice-Davies

How many of us remember when our houses had one light bulb per room and possibly one plug socket?

 

[Richard n Ann]

Being the devil's advocate here, curious too... Why spend £2000 on batteries and inverter to save you spending €18 on LPG every year?

I know TV uses electric but talking about the use of high power cooking and heating equipment.

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[G1969]

Being the devil's advocate here, curious too... Why spend £2000 on batteries and inverter to save you spending €18 on LPG every year?

I know TV uses electric but talking about the use of high power cooking and heating equipment.

Yes my dilemma is cost v benefit, but also within this is increased flexibility and choices. At the moment we still use campsites that have unmetered electric, but my view is more will go metered, and the cost some charge is circa £10 v non electric per night!, so this soon stacks up, and could turn out to be a smart long term investment.

 

[Hoovie]

When we first went camping EHU was unheard of. Our first caravan had one 75Ah battery and we could survive a week with that.

I bet you had a good supply of spare gauzes for the gas mantels though

 

[autorouter]

I think many would be happy with the energy equivalent of an 11kg Safefill LPG bottle. Since 1kg of LPG contains about 14kWh of energy, an 11kg Safefill gas bottle contains about 11 x 14kWh =154kWh. In terms of 12V batteries that's about 154000/12 = 13000Ah. But then some people would want two Safefill bottles...

 

[dunnah01]

The only time you may need any serious off grid is a couple of times a year if you do the long rallies so if you size your lithium setup for that scenario it works out about an extra £100/night. May as well get a hotel room tbh

 

[Ingwe]

The adage I’ve followed with regard to acquiring material things applies:
1. Do you need it?
2. Can you afford it?
Both questions require an affirmative answer. Otherwise, wallet put away.

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[WESTY66]

The adage I’ve followed with regard to acquiring material things applies:
1. Do you need it?
2. Can you afford it?
Both questions require an affirmative answer. Otherwise, wallet put away.

The adage I always follow is “better off looking at it than for it”

 

[JockandRita]

Why spend £2000 on batteries and inverter to save you spending €18 on LPG every year?

I don't know where you get that assumption from. If using the MH all year round whith gas heating on 27/7 during winter months, we can very easily go through an 11Kg refillable cylinder in 5 x days, no sweats. So, anything that reduces that gas consumption momentarily, has to be a good thing.

Cheers,

Jock.

 

[Roger S]

I have now got 470a and 400w solar which I will increase in the summer the reasoning is to get away from finding gas its a pain in the butt sometimes. Gas is a very good energy but in europe its getable but becoming a bit more inconvienient and in the UK a real pain.

 

[Richard n Ann]

I don't know where you get that assumption from. If using the MH all year round whith gas heating on 27/7 during winter months, we can very easily go through an 11Kg refillable cylinder in 5 x days, no sweats. So, anything that reduces that gas consumption momentarily, has to be a good thing.

Cheers,

Jock.

I suppose it depends on how long you're in the van for and during which season. If you live in the van and use heating for 6 months of the year you might get through £500 worth of gas a year
We just use gas for cooking and very occasional heating and the last gas (2 x 6kg) lasted 3 years and still wasn't empty when I refilled it

 

[Lenny HB]

We just use gas for cooking and very occasional heating and the last gas (2 x 6kg) lasted 3 years and still wasn't empty when I refilled it

Your motorhome use is not the norm is it Richard.
I've already filled with 55 Lt so far this year and will be filling with another 30 to 40 Lt next time I use the van.

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[Richard n Ann]

Your motorhome use is not the norm is it Richard.

Probably not, I'm the extreme in the other direction, if it wasn't for the compressor fridge we manage with a 5ah battery

 

[JockandRita]

Here in Spain and since 11th January, we are on Spanish 12Kg cylinder No5, and not using our two full refillables until we abolutely need to. The gas usage is heating and the F/F mostly, as the cooking is electrical via the inverter and lithiums. We don't do cold ........... in any shape or form.

Cheers,

Jock.

 

[funflair]

Being the devil's advocate here, curious too... Why spend £2000 on batteries and inverter to save you spending €18 on LPG every year?

I know TV uses electric but talking about the use of high power cooking and heating equipment.

I couldn’t find a gas microwave or coffee machine so had to do it, oh and the gas blows out outside in the wind but the induction works a treat

 

[Lenny HB]

oh and the gas blows out outside in the wind but the induction works a treat

Yep, I'm a big convert

 

[mikash]

I suppose it depends on how long you're in the van for and during which season. If you live in the van and use heating for 6 months of the year you might get through £500 worth of gas a year
We just use gas for cooking and very occasional heating and the last gas (2 x 6kg) lasted 3 years and still wasn't empty when I refilled it

Come spend the winter in Finland and it can easily be 200-400€ / month on gas depending on the latidude
And that sort of leads to your original question - for me, gas heating doesn't suit too well, because there are colder stretches in the winter where you have to buy more gas every other day. So you need to either drive somewhere to buy it or stay at a camping ground which sells it. I want to be self sufficient for a week minimum in the winter (no driving, no solar) so I have to use diesel heating to get even close.
With the gas heating out of the picture, having a gas system just for the hob feels like an unnecessary complication. I have a backpacking stove and canisters for backup anyway. I also have a place up north where I have EHU but the nearest gas station that sells gas is 30km away. When traveling, being dependant on just diesel and electricity is slightly simpler, even if the gas for just cooking lasts quite some time.
Of course there are the added bonuses of less moisture, less unhealthy particles to breath and no gas leak risk, but I don't consider those that significant and they certainly wouldn't stop me from using a gas hob if it otherwise felt more practical.

It is expensive though. For the next van it seems 10kWh of batteries is the bare mnimimum if I want to be anywhere close to that 1 week self sufficiency goal. With gas hob + gas oven instead of induction hob and air fryer I could do with like half of that and wouldn't need a big inverter. Not sure if I would need an inverter at all, actually. I've been trying out a 12V heatable lunchbox and a usb-charged esporesso machine and those seem adequate for my use (and use very little power) so microwave and 230V coffee machine are not necessary either.

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[dunnah01]

Has anybody worked out how much diesel you use to charge the mega lithium setups. No way solar would touch the sides of some setups in the UK?

 

[WESTY66]

Has anybody worked out how much diesel you use to charge the mega lithium setups. No way solar would touch the sides of some setups in the UK?

I use the same amount that gets me to where I’m going, the solar will do the rest

 

[Lenny HB]

I use the same amount that gets me to where I’m going, the solar will do the rest

Nope, your B2B is using power from the alternator, the alternator can not produce power without the engine running, the alternator is an extra load on the engine so the engine will consume more fuel.

 

[dunnah01]

I use the same amount that gets me to where I’m going, the solar will do the rest

I've been getting less than 5% yield from my 4kW setup for about 4 months over the drab winter so no way any moho roof setup would sustain much off grid use. It would take all winter just to charge the bank up once.

 

[WESTY66]

Nope, your B2B is using power from the alternator, the alternator can not produce power without the engine running, the alternator is an extra load on the engine so the engine will consume more fuel.

It’s negligible,the alternator would be running regardless, yes the load on it might be different but I keep the aircon off
I use a lot more diesel looking for lpg stations

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[Lenny HB]

It’s negligible,the alternator would be running regardless,

You engine is approx 12kw if it averaged running at 50% power a 50 amp B2B would consume over 10% of that power.

 

[mikash]

Has anybody worked out how much diesel you use to charge the mega lithium setups. No way solar would touch the sides of some setups in the UK?

1 liter of diesel is about 10kWh which equates to about 800Ah at 12V. You probably need to multiply that by 2-3 due to inefficiencies in the conversion, biggest being the alternator which these days I think are around 50-60% efficient at best And on top of that whatever diesel is consumed for the vehicle idling/driving of course.
Depending on the season solar might provide most / all of your energy, some or none. You're probably not using 800Ah / day anyway, the huge capacity is there for longevity. So the important figure is daily consumption vs daily yield, not maximum capacity., as far as solar goes. B2B is nice to have on longer journeys but in winter my game plan revolves around a weekly EHU topup, one way or another. Driving or idling for that amount of energy is not practical.

 

[WESTY66]

You engine is approx 12kw if it averaged running at 50% power a 50 amp B2B would consume over 10% of that power.

Don’t forget I’ve got the mighty 3.0L Iveco powerplant, not the latest fiat offering out of a Mamod box

 

[Lenny HB]

Don’t forget I’ve got the mighty 3.0L Iveco powerplant, not the latest fiat offering out of a Mamod box

160 bhp = 12kw, if its a 180, 13.4kw.

 

[WESTY66]

160 bhp = 12kw

180bhp if you please the missing 20bhp from your calcs should make up for the drag on the alternator belt
But I get your point, it would take me twice as long as you to put it back
That said I didn’t notice any noticeable difference in mpg coming back from offgrid with the 2x50a B2Bs and the extra battery, it regularly returns 27mpg overall up hill and down dale, which for the size of it isn’t too bad.

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