Inverter / Lithium battery question (1 Viewer)

[Wack]

In the (house)garage not fitted yet I've got a dometic freshwell 3000 AC unit

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designed to be fitted in a cupboard, with pipes running into the van to cool the hab area

for a crazy amount of money you can buy a suitable inverter to power it while driving , as I understand the instructions it runs off 12V which is supplied by the battery via the mains hookup charger

Now I see this , I know it's a crazy number for a battery and I wouldn't consider it at that money but , as it says it's capable of supplying 4000w would the alternator be powerful enough to keep that topped up while on the move to power the AC or am I thinking pie in the sky

 

[Tombola]

If you have a suitable battery being charged by a b2b while driving then in theory yes no problem.
Depends how much energy it draws whether it will be worth it. Cant be much more than a fridge can it ? my fridge pulls about 13a from the battery when it kicks in, I have a 200ah lithium and works ok, leave me anywhere between 30-50% for the next day if set on low and as long as sunny or driving(b2b) keeps me going.

When stopped, I imagine with the 400ah battery should be plenty for a day or 2, even if it was run via 230v on an inverter.

Truma have a range too, this si a smaller version with power consumtions just 4a or less
https://www.jacksonsleisure.com/car...hir-compact-under-bench-air-conditioning-unit

 

[Wack]

Thanks tombola

Having had a read of the capabilities I think having it running while driving may be a disappointment, I've also re-read the fitting instructions and it needs 230v so will need an inverter to work on the move , whether a large capacity battery would mean the inverter doesn't need to be connected directly to the alternator I don't know.

It's already looking like more trouble than it's worth to get it working on the move though on the first trip to a hot country I might change that view

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[jongood]

This type of ac is generally a lower draw than the conventional roof mounted one although ducting can be a challenge as a retrofit because you need to get them up high or you will just end up with s cold floor.

I would imagine it could run off a decent inverter with a reasonable size battery pack but you would have to do the numbers on current draw and your alternators ability to keep up with demand.

 

[Wack]

I am quite surprised at the amount of motorhomes that don't have even cab AC fitted as standard , given how much they cost new you'd think the chassis they start with would have AC fitted, especially as you'd really struggle to buy a new car without it these days

 

[Wack]

This type of ac is generally a lower draw than the conventional roof mounted one although ducting can be a challenge as a retrofit because you need to get them up high or you will just end up with s cold floor.

I would imagine it could run off a decent inverter with a reasonable size battery pack but you would have to do the numbers on current draw and your alternators ability to keep up with demand.

Thanks
I've already looked at ducting, there's an under bench area big enough for the AC unit with enough room ajacent to run the pipes through the other side and vent them through the bottom of the cupboards , the problem would be getting cooled air to the cab as i'd need to extend the pipes and seal the cab off if they were going to do anything to cool it

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[funflair]

You need to remember that cold air is heavier than warm air so you need to duct it to a high spot really, we have a roof mounted fresh-jet 2200 that runs off the batteries via inverter no problem when parked up but that was with 520watts solar and 320ah lithium, also runs off the inverter when driving but the cool air tends to stay behind us in the habitation and we still run the vehicle air con.

 

[Neil S]

I am quite surprised at the amount of motorhomes that don't have even cab AC fitted as standard , given how much they cost new you'd think the chassis they start with would have AC fitted, especially as you'd really struggle to buy a new car without it these days

Depends what age of Motorhome your looking at
It was less common in Pre 2010 models
But after that most manufacturers included it .

 

[Wack]

You need to remember that cold air is heavier than warm air so you need to duct it to a high spot really, we have a roof mounted fresh-jet 2200 that runs off the batteries via inverter no problem when parked up but that was with 520watts solar and 320ah lithium, also runs off the inverter when driving but the cool air tends to stay behind us in the habitation and we still run the vehicle air con.

thanks, which inverter do you have , I bought a sterling power products one at an auction but it's designed for a boat, it'll work in a van but weight wasn't a factor when they made it

It has to be over 25kg

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[Wack]

Depends what age of Motorhome your looking at
It was less common in Pre 2010 models
But after that most manufacturers included it .

As most of them are fiat based I just look at the space between the heater controls for the button as quite often they forget to mention it in the spec, I think it'd cost about 3k to retrofit cab AC to my 2008 ducato

I was thinking of changing it for one with it already fitted but as it's only done 36k and drives like new I can't really justify it , especially with the CV19 tax on vans now, what I should do is sell at the top and wait for the crash whem benidorm comes back on stream

 

[DBK]

You can get 12 volt A/C units designed for vehicles. They may not be very powerful but if you are just looking for a system to cool the cab end of the vehicle while driving they are an option. Some of them will need a hole cut in the roof though.

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[funflair]

thanks, which inverter do you have , I bought a sterling power products one at an auction but it's designed for a boat, it'll work in a van but weight wasn't a factor when they made it

It has to be over 25kg

We have a Buttner 3kw inverter charger with network compensation but in the last van we had a Merlin 3kw, all Pure sine Wave of course.

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[Tombola]

thanks, which inverter do you have , I bought a sterling power products one at an auction but it's designed for a boat, it'll work in a van but weight wasn't a factor when they made it

It has to be over 25kg

I run a victron b2b and a 3kw inverter while driving and I fitted the switch so I can turn the b2b on or off when I like. Charges my ebikes and runs the fridge(when I forget to switch back over to alternator) no problem.

This will run your ac fine while on the move, an dkeep your lithium going
30 ah victron b2b
Inverter 2kw (probably even less)
and if you have a decent ah lithium battery you can run the ac when stopped even at 4ah isnt gonna kill you esp with solar.

just make sure the lithium battery discharge is able to withstand the inverter loads (if you pile it on that is) some cheap batteries dont have the capacity to make use of the full ah draw.

 

[BillandHelen]

We also have a roof mounted fresh light aircon that we run when stationary off our 200amp of lithium through a 2000w inverter. Works well, draws about 6/7amps, varies a bit as not always on chill, and runs fine when travelling if required, lithium topped up by 60amp b2b. So it’s all doable, just needs the right kit.

 

[eddie]

We run the generator when its hot so we can run the AC at full chat, to keep the dog cool!

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[Wack]

We run the generator when its hot so we can run the AC at full chat, to keep the dog cool!

I've got a Honda generator , was wondering about running it in the garage with the exhaust extended to the outside but was concerned I'd end up like a fighter jet on afterburner down the M6

 

[eddie]

I've got a Honda generator , was wondering about running it in the garage with the exhaust extended to the outside but was concerned I'd end up like a fighter jet on afterburner down the M6

Ours is a 5.5Kw Onan built into the camper at the factory, but my mate fabricated a aluminium box, which he set into the floor, with air vents with splash covers. He bought an LPG conversion for it and plumbed it into the on board gas, and removed the control panel, extended the wiring and mounted it alongside the control panel for convenience

He's quite pleased with it, but I must admit that I think its a little noisy and if I'd gone to that much trouble I would have bought a Honda unit rather than a cheap Chinese job

 

[Wack]

Ours is a 5.5Kw Onan built into the camper at the factory, but my mate fabricated a aluminium box, which he set into the floor, with air vents with splash covers. He bought an LPG conversion for it and plumbed it into the on board gas, and removed the control panel, extended the wiring and mounted it alongside the control panel for convenience

He's quite pleased with it, but I must admit that I think its a little noisy and if I'd gone to that much trouble I would have bought a Honda unit rather than a cheap Chinese job

I bought a low use Honda EU20i and the LPG kit so I suppose I could get it set up the same as yours in the garage

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[autorouter]

In the (house)garage not fitted yet I've got a dometic freshwell 3000 AC unit

I've looked on the Dometic website, and it doesn't state the electrical input power. It states the cooling capacity (ISO5151) is 1758W. Elswhere on the site it states the cooling capacity to be 2700W, and the heating capacity to be 3000W. It doesn't state the electrical input power anywhere I can see.

There should be a plate on the device that states this. What does it say?

 

[Bessy765]

Our Dometic Freshjet 2200 will run quite happily from a 6 amp supply, rough calc you will need 28 amps @ 12 volt d.c. to produce 1 amp at 240 volts a.c.allowing for inverter inefficiencies and voltage drop.

 

[mitzimad]

ac unit and a gennie ,how much payload will that leave?

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