Converter question

[Bobholthaus]

Can someone please explain to me what size converter I should buy relative to the amp hours of my battery(s)? If I only have 100 amp hours, is a 60 amp converter (intellipower 60 amp is what I am considering) too big? And, how much power will these put out for filtered DC? I am trying to run a high amp stereo amplifier (maybe two amplifiers) from a 3500 watt generator in a party bus. Does the 60 amp rating on the converter have anything to do with how much power I can draw through it from the generator to the DC load panel? These amplifiers claim to have a 45 amp draw while in use. As that is something like 4500 watts, my generator isn't going to be able to handle that load... But I can't image that one Sony $200 amplifier pulls that many amps. So something must be wrong with the waupy I'm reading the manual. Thanks for any advice. Converter info is hard to come by.

[bus-bro]

A 60 amp converter will deliver 720 watts at a nominal 12 volts. Is the amplifier a 12 volt unit? If so, that's 540 watts. The generator could do several, the converter one. The converter provides 12 VDC from 120 VAC, plus a (small) battery charge current. Your battery could supply the max. amplifier current maybe an hour (the amp-hour rate is figured with a 20 hour draw.)

[Bobholthaus]

Thank you. Can you explain to me the math please andbhow you came up with it? Thanks again.

[roach711]

Watts = amps x volts.

Amps = watts divided by volts

Volts = watts divided by amps

Your Intellipower converter takes 1000 watts of the 120v, 30amp output (120v x 30amps = 3600 watts) from your generator or shore power and converts it into 60 amps (816 watts) of 12v nominal (actually 13.6v) DC power. There's usually about a 20% power loss when CONverting AC to DC or INverting DC to AC (confused yet?). I believe that unit also has the charge wizard three-stage battery charger built in so when your genny is running you're charging the batteries as well as powering whatever else is plugged into your 12v system.

Check the tag on the sound amplifier for actual voltage and amp draw. I'm not sure whether the sound output watts of an amplifier has anything to do with the actual watt draw of the amp. If the amplifier is a 120v unit you need to connect it directly to a 120v source (genny, DC to AC inverter or shore power), not the converter. If it's a 12v unit the converter will do you fine, as long as the sound amp/s don't try to draw more than the 60 amps the converter can output.

As to the size of your battery bank, my understanding is that the charge wizard senses the state of charge in your battery bank and adjusts the charging amps accordingly. I've never read anything that would suggest that the size of the bank was an issue. A small bank would charge faster than a large one. Given your 45 amp draw, it would appear the 60 amp Intellipower would fit the bill with a bit of power to spare.

[Bobholthaus]

Thank you for the explanation. It is a 12v amplifier and the manual says that it can draw as much as 45 amps, which is what was confusing me. I always forget about the 30 amps at 120 volts (3600 watt output of gennie) versus 45 amps at 13.6 volts (612 watt draw of Amp); that is a crucial thing not to forget, because if you just think about the amps (which I was doing), the 45 amp amplifier would overpower the 30 amp generator (which is obviously not the case once the math is done correctly). So, the one converter at 60 amps (816 watt output), minus the power loss, should still be able to run the amplifier at full tilt (612 watt draw at full volume) even if the battery wasn't even hooked up (which will never be the case). So I'm fine. If we install another amplifier, which we are planning on doing at some point, and run them both at full power, the converter may not have enough juice (depending on volume level) to run both amps, and keep the battery charged. As it is unlikely the volume will be turned all the way up for extended periods of time, I think we'll be okay. I'm going to hook up an Argus Battery Monitor (http://www.argusanalyzers.com/) to the battery and keep an eye on the volts and we'll see how this whole thing works. Thank you again for taking the time to explain. It's people like you that makes the lives of people like me easier, and for that I am grateful.

[roach711]

My pleasure Bob. Other people here explained the same stuff to me not so long ago.