a bit off topic - running a projector on LiPo

[nonlineartom]

For an art project I'd like to run a 2500 lumen projector off an external battery pack, I have 1.2Kwh of LiPo lying around so I need to find a way to get the LiPo keeping the projector happy. I can't seem to find a power consumption spec for the projector but I'm sure it will be shy of what the batteries can supply. I was thinking of using a 1000W current interverter like you use in cars to run mains equipment. But my batteries are all 6s 22V nominal and I believe those current inverters are 12V only. Whats the cheapest way to get the 240V AC projector working on 22V DC?

 

[nonlineartom]

ah, 233W power consumption on full brightness.

 

[liveforphysics]

I have a 24vdc in to 240vac output 1500w inverter that cost me something like $50 on ebay.

I have a hunch your projector will work equally well on DC as AC though. You've got about 10 packs or so right? If you feel like taking the risk of destroying your projector (a risk I would take with mine, as I'm 90% sure it will run fine from AC), stick them in series and see if it runs.

 

[E-racer]

Does the projector have an internal (like a desktop computer) or external (like a laptop or cellphone charger) power supply?

 

[nonlineartom]

internal power supply. Just fed with a kettle lead 240V AC.

I'm not a massive fan of hooking up 240V of LiPo. Wouldn't the spark be pretty hefty? I've killed a projector before by running it off a petrol generator. I'm not entirely sure why but I was told it was something to do with the generator being a "dirty" power supply and a spike in current blew something in the project. I can't afford for that to happen, I presume those cheap DC AC boxes provide a "clean" supply which won't risk blowing sensitive electronics?

I'm guessing there is also quite an efficiency loss with those cheap ACDC converters?

 

[voicecoils]

if you're worried about the projector, get a proper name brand pure sine wave inverter and something with power 'headroom' like this one:

http://www.xantrex.com/power-products/power-inverters/prosine-international.aspx
http://www.amazon.com/Xantrex-Technologies-Prosine-1000-500-Watt/dp/B0000225DB/

If your projector uses 223 watts, don't get an inverter of the same size. Get something in the 500-1000W range. The inverter I've linked to is 85% efficient, so make sure to account for that when sizing your.

That's not a cheap option though.

Alternatively you could buy a cheap 2nd hand projector and pair it with a cheap modified sine wave inverter. There are some 24v ones out there which have a voltage range up to 31 Vdc or so. Then if the projector blows up, you won't be as sad

 

[magudaman]

I powered a projector off a 300w continuous sinewave inverter and my 66V A123 Pack. It was pretty wasteful though. I had to run the 66V through a DC-DC converter that turned the power into 12V then into the inverter to AC to the projector which then most likely turned it back into DC. I would highly suggest a sinewave inverter though. If your not strapped for cash you can get a 24v or 36v or 48v 500w sinewave inverter on ebay for around $130. I paid a lot more for my 12V one back in the day :x

 

[gogo]

If a DLP LED projector would be bright enough, you could use a
smaller battery. Mine came with a lithium battery good for 3 hours.

 

[ZOMGVTEK]

internal power supply. Just fed with a kettle lead 240V AC.

I'm not a massive fan of hooking up 240V of LiPo. Wouldn't the spark be pretty hefty? I've killed a projector before by running it off a petrol generator. I'm not entirely sure why but I was told it was something to do with the generator being a "dirty" power supply and a spike in current blew something in the project. I can't afford for that to happen, I presume those cheap DC AC boxes provide a "clean" supply which won't risk blowing sensitive electronics?

I'm guessing there is also quite an efficiency loss with those cheap ACDC converters?

Cheap inverters have VERY dirty power. For regular use, I wouldn't recommend running anything besides resistive heaters or incandescent lights off 'modified sine wave' inverters. A true sine wave inverter will run the thing just like off the wall, but they're not cheap.

DC from batteries is about as clean as it gets. The only real question is if the supply will handle it. The only real difference is DC is 'ON' 100% of the time, and never crosses zero. This tends to be more of an issue for switches, since the arc tends to not self extinguish with HV DC. Most switching power supplies are perfectly happy with DC, some are not.

Non-Inverter 'stator' generators typically have questionable power output. If its a big generator, and its ballasted with a few hundred watts of resistive load, it should be OK. However, hammering the generator with intermittent loads can result in serious voltage spikes. With a 240V generator, these spikes can take out equipment. At least with 120V inverters, most SMPS can tolerate 250-300V, so it's not really possible to even get that high of a surge.

IF it works, DC will leave the projector happy. If it does not, it can blow up the power supply. It's always a risk when you use equipment in ways they were not intended.

 

[nonlineartom]

Thanks for the advice, I originally tried running a projector off a little petrol generator. I was told it was a very "dirty" power supply and sure enough it toasted a big projector. I guess anything that's a sine wave DC supply will be whats needed to prevent popping an expensive bit of kit, would a surge protector help at all? I need to use anything north of 2000lm projector which rules out little LED units, this is for projecting onto a big building see.

Thanks again all

 

[magudaman]

Thanks for the advice, I originally tried running a projector off a little petrol generator. I was told it was a very "dirty" power supply and sure enough it toasted a big projector. I guess anything that's a sine wave DC supply will be whats needed to prevent popping an expensive bit of kit, would a surge protector help at all? I need to use anything north of 2000lm projector which rules out little LED units, this is for projecting onto a big building see.

Thanks again all

Weird I got a topic replied to email last night at 1 am?!? Anyhow was reading back over this and see you had remaining questions anyhow. A surge protector will not help at all. It doesn't really have any filter properties what so ever.

 

[nonlineartom]

Thanks for getting back, in the end I used two HUGE 12V lead batteries from a canal boat, something like 500ah total through a 2500W pure sinewave inverter. I know a surge protector wouldn't filter the power at all, I just presumed it might prevent a device killing spike of power, which is what happened from the little genny to my old projector.

 

[nonlineartom]

That's what the end result looked like. Total cost = £0

made the local press

 

[ZOMGVTEK]

Neat.

A beefy sine wave inverter is a nice thing to have laying around if you ask me. Was it the 'cheap' Sunforce model?

 

[nonlineartom]

I don't actually know, it had an LCD panel on the front and two beefy fans on the back. It belongs to a friend who runs big gigs in the middle of nowhere of these leisure batteries. Charges the batteries with big solar panels.