frolinmod
06-09-2011, 12:08 PM
If you have recently received a Paramount MX and are wondering how you're going to power it in the field, here are a few options:
1. The Software Bisque 48V LiFePO4 battery pack (http://www.bisque.com/sc/shops/store/All+Products/Hot+Products/PowerSupplyMEMX10AH.aspx).
2. 12V battery + AC inverter (http://www.donrowe.com/inverters/puresine_150.html) + the included AC power brick (HUP80-18) (http://www.bisque.com/sc/shops/store/All+Products/paramount-me-power-supply.aspx).
3. 12V battery + 12V to 48V DC-DC converter (http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-Step-Up-48V-3A-150W-/120764254558).
4. Four 12V batteries connected in series.
My Paramount ME uses very little power at 48V. It uses about 200ma while tracking, about 600ma while slewing at the default rate and about 900ma maximum while slewing at the maximum rate. The Paramount MX should be similar.
If you don't mind the up-front expense, option #1 is cost effective in the LONG run. LiFePO4 batteries are light, will sustain many charge/discharge cycles and have a long lifetime. It may seem like 5AH or 10AH isn't much capacity, but this is at 48V and thus equivalent to four times as much running time as at 12V. This is also just for the mount, not for all your other equipment. Therefore that 10AH battery may last three nights or more. This is a 48V battery pack, so it's only going to power your mount. You'll need another battery to power all your other equipment unless you can power it all off the 12V and 5V power output sockets on the MX control panel.
I think most people would find option #2 to be the easiest and most convenient while involving the least cash outlay in the short run. Note that AC inverters are isolated, which is good.
Option #3 requires some technical skill. It also requires that you fully understand that the DC-DC converter mentioned here is NOT isolated, so you may be subject to ground loops if you power more than just the converter with your battery. The easiest way to ensure that you will not have ground loops is to use a separate battery to power the converter than you use to power all your other 12V equipment (such as dew heaters, cameras, focusers, rotators, etc).
I recently did an analysis of option #3, using a 12V to 48V DC-DC converter (http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-Step-Up-48V-3A-150W-/120764254558). I found that option #3 was 40% more efficient than option #2 while tracking and 30% more efficient than option #2 while slewing at the maximum slew rate (100) and maximum acceleration (800) settings. Option #3 gets very close to the efficiency of option #1 or #4. Less than 10% difference. I measured this with my Paramount ME. The Paramount MX should be similar.
Option #4 is the most efficient option. I don't see too many people lugging around four heavy 12V batteries (or eight even heavier 6V golf cart batteries or whatever). But if you leave your batteries in your vehicle and run a long thick battery cable to the mount, it's certainly an option. 48V golf cart battery chargers are also readily available so that you don't even have to charge the batteries separately. You could run for literally weeks between charges this way.
1. The Software Bisque 48V LiFePO4 battery pack (http://www.bisque.com/sc/shops/store/All+Products/Hot+Products/PowerSupplyMEMX10AH.aspx).
2. 12V battery + AC inverter (http://www.donrowe.com/inverters/puresine_150.html) + the included AC power brick (HUP80-18) (http://www.bisque.com/sc/shops/store/All+Products/paramount-me-power-supply.aspx).
3. 12V battery + 12V to 48V DC-DC converter (http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-Step-Up-48V-3A-150W-/120764254558).
4. Four 12V batteries connected in series.
My Paramount ME uses very little power at 48V. It uses about 200ma while tracking, about 600ma while slewing at the default rate and about 900ma maximum while slewing at the maximum rate. The Paramount MX should be similar.
If you don't mind the up-front expense, option #1 is cost effective in the LONG run. LiFePO4 batteries are light, will sustain many charge/discharge cycles and have a long lifetime. It may seem like 5AH or 10AH isn't much capacity, but this is at 48V and thus equivalent to four times as much running time as at 12V. This is also just for the mount, not for all your other equipment. Therefore that 10AH battery may last three nights or more. This is a 48V battery pack, so it's only going to power your mount. You'll need another battery to power all your other equipment unless you can power it all off the 12V and 5V power output sockets on the MX control panel.
I think most people would find option #2 to be the easiest and most convenient while involving the least cash outlay in the short run. Note that AC inverters are isolated, which is good.
Option #3 requires some technical skill. It also requires that you fully understand that the DC-DC converter mentioned here is NOT isolated, so you may be subject to ground loops if you power more than just the converter with your battery. The easiest way to ensure that you will not have ground loops is to use a separate battery to power the converter than you use to power all your other 12V equipment (such as dew heaters, cameras, focusers, rotators, etc).
I recently did an analysis of option #3, using a 12V to 48V DC-DC converter (http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-Step-Up-48V-3A-150W-/120764254558). I found that option #3 was 40% more efficient than option #2 while tracking and 30% more efficient than option #2 while slewing at the maximum slew rate (100) and maximum acceleration (800) settings. Option #3 gets very close to the efficiency of option #1 or #4. Less than 10% difference. I measured this with my Paramount ME. The Paramount MX should be similar.
Option #4 is the most efficient option. I don't see too many people lugging around four heavy 12V batteries (or eight even heavier 6V golf cart batteries or whatever). But if you leave your batteries in your vehicle and run a long thick battery cable to the mount, it's certainly an option. 48V golf cart battery chargers are also readily available so that you don't even have to charge the batteries separately. You could run for literally weeks between charges this way.