Good Point Mark. We had been discussing putting a roof over the station and we think it's a good idea also!

 

Ok Guys I think it's time to start picking out the parts of the charging station and pricing them.
From the calculations it says we need 252.3 Ah each day we use the station, if we had eight chargers hooked up. The problem with 252.3 Ah is that is puts over budget since a decent 12VDC 200Ah battery will cost $468.95. Plus I think most days we will only have four chargers hooked up and if there are more we can always charge up the station with the jumper cables.

I vote that we start with a 100 Ah battery ($251.995) and make room for four more to be added over the years. This also allows in the budget for decent charge control and monitoring electronics so we can gauge the system use over 2010 as well as for wood and wire etc.

What do you guys think?

 

just a thought, Is the expected lifespan or the ability to hold charge under load of the glass matt battery significantly better than say a standard deep cycle to justify the higher cost. 3 standard 100ah deeep cycles would cost about the same........now i'm going to have to dig into the boring details of battery specs. :geek:

 

meistertek, I have in my house four 6v batteries that run the house in a power-failure. They are connected to a 24v inverter. They last about 8hr running my fridge, computer, tv and the ceiling fan and some lights. They are rated between 225a and 250a, depending on the price. They cost here, in the Dominican Republic, between $100 and $120. I think they are the batteries that are used on golf-carts.

 

Instead of a wooden power strip try using composite decking, it should never warp in the elements and it certainly won't conduct electricity.

If you went for solar power you could always build your own panels, i don't ave any websites off the top of head, but I'm sure if you google it you'll find plenty of resources.

Louis

 

Thanks TigerPlot, Maybe we don't need batteries as big as we think since you can run so much on the four batteries you have. Golf cart batteries are similar to the batteries we are considering and the price is very similar since we are looking at 12v and you have 6v. The batteries you have cost between $100 and 120 for each 6v battery right?

 

Thanks Louis, that's a good idea to use composite decking, since this station will be out in all kinds of weather. It looks like building our own solar panel can save money and result in a better panel than store bought! We are also considering building a wind turbine and possibly a lawn mower engine connected to a alternator. But we will first build the charging station and charge it's storage batteries with our cars. The other power sources will be for future projects, but we want to keep them in mind so we can build the charging station to accommodate these ideas in the future.

 

Ummm - the term "composite power strip" scares me, especially if someone reads that and thinks you're talking about some graphite or carbon epoxy panel, which is extremely conductive!
Louis , maybe you were talking about fiberglass panels, or composite wood (particle board). :?:

 

Composite decking is made from wood and plastic. It can be bought at your local home improvement store, generally 2x6" x 8', 12' and 16' in length. No worries, non-conductive, and won't swell when exposed to water.

 

That is correct. The price is per battery. The point is that they are meant to be used for heavy loads with lots of capacity.

 

Jim found this deal recently on a solar panel setup form Harbor Freight http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=90599

 

Our club recently built a charge stand and put it into use this year. We have 2 deep cycle farm and implement batteries that cost us around $250 for the pair. We are also using the solar panels from harbor freight. This setup worked all summer long for us. We had electric combat on Friday evening with each person (between 6 - 12 folks) flying 4-5 rounds on 2 and 3 cell 780 - 1000 mah packs. I also used this system to charge my 6S 5000 mah packs in my electric LT-40 at 2C without an issue. We never had a hiccup until October. The system needed to have the batts recharged every couple weeks through us hooking up a small generator, or just taking them home to hook up to the car charger. There just wasn't enough daylight hours to keep up. So far, this hasn't been an issue, as the drain on the system slacked off with the cold weather. I'll get a picture next time out out at the field.

 

I added a bunch of links to the first few posts if you want to :geek: it out, I know I have been reading everything I can about charging and batteries.

Good question Helium, for me I am wondering if AGM batteries justify their extra almost double cost in our application. AGMs do have lower internal resistance and supposedly take freezing conditions and other abuse that we will be doling out at the field. The more I think about it I wonder if we have goofed up the batteries we have right now, they seem not hold as much charge as they used too. Actually the best performance seemed to be when Dave first installed the single deep cycle and that lasted quite a while, but recently it seems like we have to charge them all the time even though the bank is twice as big. And this happens even on light charging days with not many people charging.

 

From the ton of stuff I have read on batteries and charging :ugeek: it seems like the best set up for us would be:

1. Use AGM Batteries
or Industrial Deep Cycle Batteries (Often called Fork lift, Golf Cart or Traction Batteries)

2. Use our existing jumper cable connector for charging back up to 80%

3. Use a small solar panel and charge control set for our battery type and use it to maintain and top off the batteries to 100%

Pro and cons behind above suggestions:
AGM Batteries: More expensive, survive freezing better, charge faster (lower internal resistance), take abuse better, can survive total discharge better, will not leak acid even when broken, low self dischage 1-3% per month, no hydrogen fumes (completely sealed).
Industrial Deep Cycle: Two times cheaper, last the longest if treated right, will leak acid if broken, release hydrogen gas, may need watering, may not survive freezing, higher self discharge 2-10% per week.
Charging with car: will charge batteries fast, may want to watch current draw to prevent burning alternator, we should probably place a warning label the connection port on the station and provide a current shunt to monitor amperage draw. Most cars can only provide 13.8v for charging and will bring the bank only to 80%.
Solar panel with charge control: Will allow topping off the batteries to 100%. A good charge control will have three stage charging (bulk, absorption, float) greatly extending battery life. A good charge control can accept more panels or wind turbines later. Unfortunately I cannot find a charge controller that will take power from a car alternator, or at least it warned against in the manual.

 

Thanks Brother Pain! We currently have almost the exact same system as your club and it has worked well for us for about a year and half now (maybe it's two years). We have two deep cycle batteries and a RV solar panel with charge control. It seems like we are running into the limits of the system now though, we often discharge our current setup until our chargers give a low voltage error and shut down (this is probably really bad for battery life). It looks like at least one of our batteries is kicking the bucket only after one year of use (it was donated, so we didn't complain). We are taking the batteries home every few weeks and they seem to not be holding a charge as long as before. The current charging station is getting more and more popular (more electric planes! ) and we are hitting it harder and harder. We also fly right through winter as we have a heated club house. I think we have been unknowingly abusive to the current system.

We decided it was time for a system upgrade before the summer. Now that we have read a little more, we would like to design a system to automatically prevent us from abusing it and that has a little more capacity and longevity.

 

I like the forklift batteries. at 6 volts we need to decide if we go with 2 or 4.

 

After reading more and comparing prices I agree with you Helium. Industrial Fork Lift Batteries (flooded lead acid) seem the best match for our budget. If we keep them fully charged during winter (prevents freezing), water them, and keep a general eye on them they will last up to 10 years. I added prices and info for Industrial batteries to the battery post at the beginning of this thread if you want to check it out.

The bottom line is:

AGM costs about $2.50 per Ah
Industrial flooded Lead Acid costs about $1.20 per Ah

We can buy twice the capacity with Industrial.

 

Ok guys we have been talking and researching for a while here is a summary so far:

Current consensus on what our new system will contain:
1. Use Industrial deep cycle flooded lead acid batteries (these are the batteries used in fork lifts, golf carts, and floor washing machines).
2. AGM batteries are too expensive for our budget and are out.
3. We will charge the batteries to 80% with our car alternators, but be wary of burning up our alternators.
4. We will install an Amp Hour meter to log usage.
5. If we have enough money we can get a solar panel and charge control to top off the batteries and disconnect the charging stations when the storage batteries are too low, or we can use the solar panel and charge control we have already.
6. Voltage and Amp draw displays will be installed so we can see what's happening as we charge our various airplane batteries.

 

For logging amp hour usage of the system and displaying voltage and current being delivered to the charge station I vote for the following components:

Eagle Tree eLogger V3 with with Wire Leads, 70 Volts, 150 Amps $90.00
Eagle Tree PowerPanel LCD Display for all eLogger versions $40.00

You can check these parts out at:
http://www.eagletreesystems.com/MicroPower/micro.htm

I already use one of these systems for my planes and it is easy to adjust for long term data recording like we need for the charging station. Also it is easy to get the data into a computer and graph it in excel or the free software from eagle tree to see trends.

Let me know if you guys think these are good parts for our charging station.

 

Found these interesting battery quick disconnects: http://www.a-i-r-inc.com/
Attached files

 

Jim found an example of what our roof could be like for the charging station, a wishing well type roof:

Attached files

 

Here is Rev 1 of the concept drawing for our charging station design.

Attached files