Running a dehumidifier off of a 12V battery (thinking of)

[AstonHill]

Evening/ morning!

Would like to run a dehumidifier in a no mains electric environment. This must be a common theme on new build building sites where dampness has occured before mains electric has been fitted right?

An example of one I could buy can be found hear

Blyss D003A-12L 12Ltr Dehumidifier - Screwfix

Order online at Screwfix.com. Ideal for removing excess moisture and controlling damp and condensation. Features automatic shut down, carry handle, LED display and reusable air filter. Comes with a 24hr programmable timer. Has a water tank capacity of 5Ltr and switches off once tank is full...

www.screwfix.com

In the specifications it states its power output is 300W

I have a 110 amp AGM battery. Now I only have a 150W "Ring" invertor as you can see hear

https://www.halfords.com/tools/gara...TaEh_e1IbjTVm-fzA4Vcd63apzH67VuEaAjjEEALw_wcB

In the specifications section it says its peak output is 300W (double its max power ratting). Will this do the job? or do I need bigger like the 300W vesion found hear

https://www.halfords.com/tools/gara...xgShslbhRTO-YU_COEeKVHp6_DWGDIOUaAoAQEALw_wcB

I think the invertors trip out at something like 11 volts. So my question is how long do you think 110amp battery will last before it trips out. The power out put of the dehumidifier says 300W; but is that only on start up or constant run? How much of my batteries 110amp capacity will be left when it drops to say 11 volts when my invertor switches off?

Thanks

 

[oldbutnotdead]

Short answer - unlikely to work and even if it did, site dampness is mostly a problem when the building is not airtight.
Even if it did work (with your bigger inverter) you'll get at most 3 hrs runtime from your 110aH (at 12v) battery. Most dehumidifiers work by cooling the input air so water condenses- this takes lots of energy, the 300w is likely to be continuous (and sounds very low to be honest).

 

[robinbanks]

This must be a common theme on new build building sites where dampness has occured before mains electric has been fitted right?

I note lot of your endeavours start from an initially faulty assumption and proceed towards a hiding to nothing based on it

 

[Mottie]

Would like to run a dehumidifier in a no mains electric environment.

 

[bernardgreen]

A wind up clockwork unit might be appropriate.

 

[Ivor Windybottom]

I've just ordered a set of these. Very cheap, effectively provides you with unpowered rechargeable dehumidifiers for use where there's no power...

Recharge Dehumidifier Set Reusable Desiccant Silica Gel Moisture Absorbing - NEW 5021196743552 | eBay

Find many great new & used options and get the best deals for Recharge Dehumidifier Set Reusable Desiccant Silica Gel Moisture Absorbing - NEW at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

I bought this after seeing Big Clive's recent teardown video...

Obviously only for small confined areas, this isn't going to dry an entire building. Perfect for my barely used shower room though, just to keep things in check. Will probably put the other in a wardrobe.

And as a bonus, you get a shoe-dryer! Obviously the recharging/heating should be done in a ventilated room, otherwise you're chasing the same water round and round.

 

[ericmark]

There are two types of dehumidifier, one has a rotating ring of a moisture absorbent substance, and a heater and air is blown through the disc to dry it out, with in and out pipes, and the other ports have the dry air in and out, so 4 large pipes. These have very little in rush on switch on, and no refrigeration unit.

The other does use a refrigeration unit, it cools the air so moisture drops out and then heats it up again. The heat pump tumble drier works like this, and it has a minimum temperature it can work in. This it how the one linked to works.

Single phase refrigeration units need to start when there is no pressure in the system, so start time is critical, too fast and inrush is too high, and too low and pressure builds up before it has started, not such a problem with three phase units, which can use an inverter to control the start so domestic upright freezers are like this now, but that is expensive, so in the main a freezer which likely uses 60 watt running, will use 1000 watt to start.

The dehumidifier you like to is cheap, so one can expect a start load of around 10 amp, this can cause problems with some generators as when over loaded the field can collapse, so would likely need at least a 5 kVA generator to power it. Which is why on building sites the other type is used. But in the main they use inferred heaters and leave the windows wide open.

I have used the type which have a simple chemical in them which attracts moisture and allows it to fill a container below, and they do work, but depends on how much moisture you want to remove.

Old caravans were a real problem in winter, the modern type have a flue which vents through the floor removing combustion products, but the old type burn hydro carbons and the CO2 and water where in the caravans air, OK in summer on an odd cold day, but in winter useless. No amount of dehumidifiers will remove that much moisture.

In old houses we had single glazed windows with catchment trays at the bottom, and small holes to direct the water outside, and the windows would always have condensate on them, they worked as a good dehumidifier. Also lovely patterns when the moisture froze.

But your idea is a non starter, an inverter will never run a dehumidifier of that type unless rather large, mine as I said before is powered but a battery which can discharge at 3 kW and charge at 2 kW with a 3.2 kWh capacity and the inverter can handle 5 kW, and it was darn expensive. And I use a 50 volt battery not 12 volt, so current is a lot less. Also not lead acid.

 

[Why Not Indeed]

Whatever it is you're trying to do, if your power source is 12V then you should be looking at things that are natively 12V rather than inverting to 230V. A quick google suggests that they do exist.

 

[AstonHill]

I've just ordered a set of these. Very cheap, effectively provides you with unpowered rechargeable dehumidifiers for use where there's no power...

Recharge Dehumidifier Set Reusable Desiccant Silica Gel Moisture Absorbing - NEW 5021196743552 | eBay

Find many great new & used options and get the best deals for Recharge Dehumidifier Set Reusable Desiccant Silica Gel Moisture Absorbing - NEW at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

I bought this after seeing Big Clive's recent teardown video...

Obviously only for small confined areas, this isn't going to dry an entire building. Perfect for my barely used shower room though, just to keep things in check. Will probably put the other in a wardrobe.

And as a bonus, you get a shoe-dryer! Obviously the recharging/heating should be done in a ventilated room, otherwise you're chasing the same water round and round.

I have read the link and watched the video and I am a bit confused as to what powers it and how long the gel lasts and weather or not it can be recharged

In the description of the listing it quotes

No Wires or Batteries​

Ultra Quick Recharge in just 2 Hours, no messy refills required!

So if there is no batteries what is to recharge?

In the video it looks like the device is connected to a 240V mains wire, so dose this mean it needs 240V mains electric?

 

[AstonHill]

The dehumidifier you like to is cheap, so one can expect a start load of around 10 amp, this can cause problems with some generators as when over loaded the field can collapse, so would likely need at least a 5 kVA generator to power it. Which is why on building sites the other type is used. But in the main they use inferred heaters and leave the windows wide open.

My generator is a 3KW max peek out put, so ok at 3KW on start ups but will not like to run like that for long

 

[robinbanks]

, so dose this mean it needs 240V mains electric?

I expect you take a lid off and pull out a metal canister full of silica gel beads and oven it for a couple of hours, evaporating all the moisture out of the beads and back into the house air so it can be absorbed back into the beads again

 

[AstonHill]

Whatever it is you're trying to do, if your power source is 12V then you should be looking at things that are natively 12V rather than inverting to 230V. A quick google suggests that they do exist.

not according to the google shopping they dont!

12 volt dehumidifier - Google Search

 

[flameport]

I have read the link and watched the video and I am a bit confused as to what powers it and how long the gel lasts and weather or not it can be recharged

No power required when in use, the gel absorbs moisture.
It is then heated with hot air to drive the moisture out of the gel so it can be used again. Preferably somewhere other than where the moisture was absorbed from.

They do work but are very slow, won't remove much moisture from anything and are certainly not for whole rooms or whole buildings. Possibly of use in a closed cupboard or tool store.

This must be a common theme on new build building sites where dampness has occured before mains electric has been fitted right?

Not in the slightest.
New builds get wet until the roof, windows and doors are installed.
After that services including electricity are installed.
However no point dehumidifying anything then as the concrete slab will still be wet and more moisture will be introduced due to plastering, decorating and so on.
By the time dehumidification might be a thing, heating will have been installed and the building is mostly complete.

The only circumstances where dehumidifiers are used in properties without electricity would be after flood damage where the electrical installation has also been damaged or destroyed.
In those, a few temporary sockets will be put in to run heating and dehumidifiers.

Would like to run a dehumidifier in a no mains electric environment.

If you really must do that, or want to run other similar items then forget about lead acid batteries. They are low capacity and only last a few 100 charge/discharge cycles at best.
It's a generator or Li-ion batteries for any realistic setup.

 

[AstonHill]

It is then heated with hot air to drive the moisture out of the gel so it can be used again.

so is electric used to do this?

They do work but are very slow, won't remove much moisture from anything and are certainly not for whole rooms or whole buildings. Possibly of use in a closed cupboard or tool store.

Not what WelshPool said, he said he has one and they work well!
Have you actully used one?

It's a generator or Li-ion batteries for any realistic setup.

But how long would the generator need to run for?

 

[oldbutnotdead]

so is electric used to do this?


Not what WelshPool said, he said he has one and they work well!



But how long would the generator need to run for?

I use the cheap non-reusable silica things in the caravan over winter - keeps the thing reasonably dry so the cushions don't get stinky and start rotting.
For drying out a flooded house you're looking at days not hours. Cheap domestic gennies aren't rated for 100% duty- in that world you are looking at proper silent diesel sets.