Lexington Area Radio Kontrol Society
AMA Charter # 3616
Rather than reinvent the wheel, I have found a site that is clear and concise when discussing the differences.
Noise is one of the most annoying differences. A generator must run at a constant RPM (~3500) to produce the power necessary to run larger appliances. As my brother-in-law, Ray (a former Home Depot employee and all around fix-it kinda guy), pointed out, think of it as a gas lawn mower running constantly next to your bedroom window. Another consequence of this constant RPM is increased gas usage (now think exhaust and fuel costs).
Inverter generators are able to adjust their speeds according to power requirements (output). Noise is less of a problem, fuel efficiency is improved, and exhaust is decreased. The power is then converted to 120 volt AC power.
On Ray's advice, we purchased the Westinghouse WH2200XLT Portable Inverter Generator (1800 rated watts) for home use. I also take this inverter generator to the field regularly. It not only gives out enough power to run my Hitec charger, but also powers the ceiling fan (approximately 50 watts) and two floor fans (approximately 90 watts each) without breaking a sweat.
What about running multiple 4 port chargers? What is the power requirement of the above?
Total charge circuit power on AC: 200 Watts (100 on channels A and C and 100 on channels B and D).
This charger will handle four 6-Cell LiPo's. One 1800 watt Inverter Generator could handle 6-7 of these chargers and still have power left over for the fans.
To handle two shelters with one ceiling and one floor fan each and 12 chargers, we would need a total of 2550 watts (approximately).Thus a power source providing over 3000 watts might be sufficient. There will be some drop off of power from the length of wire used (~50 feet X 2). Below are links for generators:
I see three possible options.
1. Two 1800 watt inverter generators, one for each shelter with a 25 ft outdoor rated cord (laid above ground) and a power strip or two for each shelter. Cost approximately $1000.00
2. One 3000+ watt inverter generator placed equidistant from each shelter (approximately 50 ft each way) preferably in the middle of the area between shelters with 50 ft of cord in conduit under ground from this central area. Cost approximately $900.00* (not including site prep for the location of the generator)
3. One 3000+ watt generator placed in the same location as noted above, in Option 2. Cost approximately $500.00* (not including site prep for the location of the generator)
Option 3 is the least expensive initially, but fuel costs will remain the same (~5 gallons over 10 hrs) whether one or two shelters are occupied.
Option 2 has greater initial costs, but would be more efficient and less noise and exhaust polution.
Option 1 has the highest initial costs (although a single unit could be purchased at a time).This option allows for the greatest flexibility, ease of transport to events or LARKS East field, and if only one shelter is being used at a time, the actual annual costs would be lowest.
*Includes costs for wheel kits, necessary for moving these heavy generators.
What about Solar
I found two links to solar power options for RC use. Both use solar panels that charge deep cycle batteries.
In each of the above cases, solar cells would have to remain out in the open,.subject to weather conditions, to charge the batteries. The batteries could remain under the shelters with the solar cells attached to a permanent structure. One problem here is that for real efficiency, the panels should be angled for best efficiency. Placing the panels on a movable surface, such as a wagon will allow better positioning. This would require daily tinkering. While these options appeal to my environmental concerns, I believe neither is a very practical solution. Our field is used sometimes 4-6 times a week. This does not leave much time for charging the batteries. (One of the above options assumed flying only on 1-2 days per week). If batteries were stored and charged within the conex, there is the problem of moving them to each shelter and hooking up the wiring prior to use. Then you have to hope you have enough storage for use. A Duracell Ultra 24M Deep Cycle Marine and RV battery costs approximately $85 and produces 75 AH. I estimate, based on the MAN article, that 5 batteries per shelter would be required (over $400 per shelter). Obviously, this option will have the largest initial costs, but the annual costs would be much lower, as no fuel costs will be involved, just possible battery replacement.
I feel the best option is to purchase two 1800 watt inverter generators. The Westinghouse WH2200XLT Portable Inverter Generator is one of the best reviewed generators available today. This option gives us the most flexibility, lower costs in the long run compared to the other generators. It is also more practical than either of the solar options for large volume use.
Keep in mind that this is only my opinion, and each club member should review this information and form their own opinion. The options will be voted upon during the September club meeting.
Dave Andersen, Webmaster