TH & Unity Horn - Solar sound system

Well we snuck in with our last gig on Sat 14th March... a day before lockdown. So here's a few snaps from the Last of the Summer 2020 vintage gigs...to remind us all what gigs were !!!

First off is one of my favourite events .. we provide sound for Melbourne Girls College Cinema Night. They have an awesome curriculum pushing alternative tech and how energy is produced / stored etc. They use pedal powered generators to charge a battery bank all day which then powers the projector at night for the film screening... we provide the off grid sound system. As well as the screening the students show off their talent with some small band / solo performances ....









The hound is of course the team boss... and goes to all my gigs.

Next up was a small " boutique " festival upstate out of Melb... Festival #23 a lovely setting, some really nice eclectic acts and generally some lovely people.. we had to turn half the system back outside after the Djs got their wish to play in the sun, in the end a great choice... we ran bands inside after dark. A highlight for me was having Freq Nasty give our " outside" half a good test with his afternoon set. The keystones were impressive..just two boxes off an FFa 6K got the place rumbling !













And the last gig for 2020... aptly named Come Together Festival .. always a tricky one for us. We need both solar trailers as we do lights , sound and backline. No change over times , just band after band. But as this was lock-down day minus one we had a few cancellations. Another lovely gig with some awesome bands











And that was the end of our gigs..... time to do the maintenance and yearly clean...and it's only Autumn...


Edited by Phil B - 01 April 2020 at 11:59pm

Bloomin eck, nice find.

Well they are quite something, yes you definately want to be sure those are discharged before working with them.

How do you connect a capacitor that big though. Do you need to bring it up to voltage slowly before connecting it to the battery, almost like a soft start?

A current limited charging arrangement probably would not be a bad idea. Lot of stress on the batteries otherwise I would think during turn on. Would depend what you are running of course, of typical SLA type arrangement I'd have to guess would be fine. After all your typical SLA will fire a starter motor for many years and those draw a good few A for seconds.

I'd not disagree, but playing devil's advocate a starter motor could easily draw 50A+ for a good few seconds sustained and SLAs are doing that every day. This cap bank may pull higher, but probably for a shorter time on turn on.

That said, first thing I would do is the maths, then I'd consult some datasheets, and then I'd probably be off to build some kind of current limiter :)

But there's no free lunch though. If you're going to head down the route of classic 3 terminal regulation with a reference source, pass device and feedback loop, you are going to lose some voltage over it. You'll get a current limiter, but may lose ~0.6V from the battery voltage over it at best. Maybe this is not a problem.