UV lamp powered direct from the leisure batteries?

[Deleted member 3614]

Long shot,

Is it possible to run a uv water treatment lamp direct from the batteries? my motorhome has a silly UK safety law where starting the engine will cut all power in the van.

UV lamps needs to be run constantly, turning them on and off will shorten their life.
I have a 1500 inverter so could use that left on which isn't affected by the power cut, can use the inverter but it uses a bit more power.

UV lamp is 25 watt on a 12-volt system.

 

[gnubie]

As a broad general statement, quite possibly, but it'd come down to the lamp itself. If your lamp is a tube and nothing more you'd need a power supply to produce the voltage needed to run it but that could run off battery. Can you post a link to a page showing your lamp & fittings?

 

[Deleted member 783]

Can you defeat whatever prevents power flowing to the van when it's running? Or is it something that gets inspected?

 

[Deleted member 3614]

I haven't bought the UV yet, what i know so far, the 12 volt is dead the same as the 240 uk mains voltage but the difference is the 12 volt has a transformer like a phone adaptor, why i,m a bit stuck Gnubie. if its 12 volts it will have a range right? like 11 to 18 volts. I will be calling them in the next few days as had to do a few things so will find out the voltage range if it helps.

if the bulb has a starter then it will not work i guess and it will have to be the inverter.

The vans power system is this Sargent unit i have no idea how to stop the power cuts when starting the engine. as for inspections, there are no rules for inside them. lol yet go 3 kg over the 3500 kg weight and suddenly you can't drive the van, our laws are nuts in the uk. so funny.

 

[gnubie]

The transformer would be a power supply to produce the voltages the bulb needs to operate. It would have a range of permissible voltage that it can run off for sure. The manufacturer/seller would be the place to ask.

 

[Deleted member 3614]

Just had the uv turn up. This is the details on the transformer. The amps seems to state a range

 

[gnubie]

This box takes 12V in and steps it up to the high voltage needed to run the lamp. The start voltage is likely to be well over 100V, operating voltage around 70V. The high amp rating would be to cover the use of a 75w lamp. You have a 25 watt lamp so it would be using less than 3 amps.

The voltages the power supply supports suggests it is intended to be run of a vehicle battery system, and will cope with 13.8v etc. That really just leaves you with the question of how long you will have to run the lamp of battery alone, and that's just a case of simple math. 10 hours at approx 3 amps, 30 amp hours. If you use a lead acid battery and want it to last, you want double that capacity, 60 amp hours.

 

[Deleted member 3614]

This box takes 12V in and steps it up to the high voltage needed to run the lamp. The start voltage is likely to be well over 100V, operating voltage around 70V. The high amp rating would be to cover the use of a 75w lamp. You have a 25 watt lamp so it would be using less than 3 amps.

The voltages the power supply supports suggests it is intended to be run of a vehicle battery system, and will cope with 13.8v etc. That really just leaves you with the question of how long you will have to run the lamp of battery alone, and that's just a case of simple math. 10 hours at approx 3 amps, 30 amp hours. If you use a lead acid battery and want it to last, you want double that capacity, 60 amp hours.

I worked out that the amps was just under 3 amps as you stated, my 260 amp agm batteries running the lamp 24 7 as you must not turn them off, my tilting solar panels produce 27 amps or thereabouts, the batteries are carbon agm so charge at a much faster rate than standard.

now wiring direct to the batteries is what i intend to do, so fitting an inline fuse is a must i gather? I can't wire into the vans main 12 volt system due to safety cut off when starting the engine.

 

[Deleted member 3614]

acutely the ballast stated a wide range of lamps voltages when i go to replace the lamp, going for the 16 volt would work out better. silly me only just spoted the lamp powers.

 

[gnubie]

Yes, fuse is definitely advisable. The fuse should go as close to the + terminal of the battery as practical.

 

[Deleted member 3614]

ok thanks, i thought so but didn't know what end, why at the battery ends? is this to stop the load going down the cable if the cable is damaged or something else?

 

[gnubie]

Yes, that's pretty much it. The lamp power supply would (or should) have its own internal fuse. The fuse you fit is there to account for wiring related problems so the closer to the battery the better as more wire is disconnected when the fuse blows.

 

[Deleted member 3614]

ok cool thanks, go that, one last thing, the solar panels will kick out a max amp of bout 27 3 x 150-watt panels, when the batteries are being charged by the mppt will these amps going into the batteries affect the uv or would the 27 amps go in the batteries only?

A bit of a confusing question I guess

 

[Deleted member 3614]

Just thought I would let you know,

UV is working fine and the batteries did very well through the night. not dropping that much, about 4-5 hours per unit from 12.6 to 12.5, thats with lights and the tv for a bit.

Thanks for your help.