| Author | Message | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Ok, here's a probably already covered question, but I'll ask anyways. I was looking at eBay for batteries. A friend of mine suggested electric wheelchair batteries, because they are small enough to move, good capacity and deep cycle. He said I may be able to find local repair shops with used batteries which had been replaced at 1/2 their life cycle. I found this: ebay auction # 9507865418 If I did my math right, and my measurements are right, I could rebuild the 4th bay in my bus to hold all of these. The 4th bay in my bus is where the wheelchair lift, an empty space, and the stock battery box is (right to left). The empty space in the middle would (could) be big enough. I was thinking of doing 3 pullout racks on top of each other, so I could get to any layer of batteries. I believe that center space to be 30" x 60" x 20". The batteries are 7.68"L 5.16"W 6.5"H, weigh 24 lbs, and are 33 Amp Hour deep cycle batteries. That would allow for 3x11 or 7x5 , depending on the arrangement. 33 to 35 batteries per layer. Since they're selling in pallets of 96, lets assume full population of 105 batteries. Yes, it would be heavy. Not outside of the capacity for the bus though. 2520 lbs, which would have been 17 average passengers, or 8 football players.  Once charged, it would give me (Watts = Amps X Volts) 41.5KW. Now the questions. Boondocking with two air conditioners, fridge, two computers @ 200W, and TV, how long would this give me on just batteries? Assume those at 110v, and the lights at 12v. If I had a 2Kw solar array, how long would it take to charge the batteries? 20 hours of sun, or about 4 days of good sunlight? If I had a 7Kw diesel generator, how long....? 6 hours assuming 100% duty cycle? If I had a 200A alternator, how long....? 17 hours of drivetime? Would the batteries be damaged by partial recharge cycles? For example, I was trying to go on just solar, and it was cloudy so the batteries discharged a lot (down to 20%). If I was gaining 10% per day while the batteries were being used, and it took 8 days to catch up, would that damage the batteries? Now, lets put this into a real world situation. Say I'm in Florida (which is very reasonable), and I happen to be there in the summer. A hurricane blows through, so my solar panels are down and covered for protection, and I'm not running the generator to save fuel. The shore power is out, and my friends are in the bus for creature comforts (lights, TV, cooked food, etc). I may be parked in a road, near a common point where friends and family may be. 3 days of cloud cover, no power, etc. Once the storm clears, the solar panels are uncovered and deployed. We'd quite likely still be on solar power for the next few days, until shore power is restored. Would this situation damage the batteries? The generator could be fired up, but if I remember right, a 7Kw generator will use about 15 gallons per day, and if it was left running for the whole time, that'd give me 8 days before the bus was out of fuel, assuming a full tank at the start of the storm. That may not be a good situation, if it's more than 8 days before local power is restored. Last hurricane I was in a couple years ago, the house I was at was lucky, they had almost continuous power, but other local areas weren't so lucky. Some local businesses were without power for another 5 days. One large grocery store, aparently without their own generator went under because all their cool and frozen stock was lost. Hurricanes are rough, and it takes a while to get power restored everywhere, even with the power company having everyone working overtime. They work fast, but there's usually a lot of damage. I did evacuation in a 4wd truck for friends and friends of friends, who couldn't get get through flooded and debris covered roads. I grew up in Florida, I don't mind a little rain and wind. | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Oh, and another question that I probably should ask eventually. What's the max load per section on an '82 RTS? | ||
| David Hartley (Drdave)
Rating: N/A |
Jw, Most wheelchair batteries are gel-cel type, they don't recover well and they don't hold up well after the 1/2-life. There are also those little lawn tractor batteries in the same size. Just not worth the time+effort+wiring+connectors and aggravation. You would be much better off using a bunch of group-31 truck batteries as they will fit more into the limited space that you think you have available. However that center section between the battery-bay and rear door is not empty. It has the substructure that is the rear suspension attached to it. There is no "set" loading factor under the RTS since it was not designed to have bays with loading. It's more a case of what you can build being able to hang on the lower bulkheads without ripping them out. (mild steel)... No solar during or after a hurricane generally providing they didn't get ripped off the roof by wind. at over $4.00 a sq ft you would need about $10,000 worth to get any efficiency and you don't have enough roof! Then you need BIG amp hours in the batteries to run anything but the basics for any given time. 8 days, Uh.. Sure !! No a.c. and very little comforts. A 7kw Generator (diesel) should burn about 6 gallons a day or .250 gallons per hour. I don't know where the 15 gallon figure came from, My 10kw uses 7 gal/day with the a/c and charger running. (1800 rpm with kubota 4-cyl engine). My other Kubota D950 @2200 with a 10kw Northstar 3600 rpm head only used a quart an hour during hurricane charlie and friends. I had to make power for 2 weeks and did it from a full fuel tank on my MC9 ( 130 gallons ) and had enough fuel to get to a station after that. My a/c was on the whole time. My fridge was on LP as was my water heater. Stove was LP so that worked for me. We rode all the hurricanes out inside the RTS as we had nowhere else to go. Rough ride and very hazardous even though we were well shielded by stand pines. Not something that I look forward to ever again. | ||
| John MC9 Rating: N/A |
Wow: "Since they're selling in pallets of 96, lets assume full population of 105 batteries. " There's so much technical doo-dah that's going to follow, from everyone that knows all about big battery banks and the electronics that keep 'em going, etc... That you may be quagmired in the doo-dah for quite some time... Before you get too deep into all the technical stuff, you oughta' seriously examine the more basic side of it all. You're going to have to maintain that battery bank; add water, test cells, tighten straps.... You're going to have to crawl on top of those batteries, inside the bay, to do so... Does ya' really wanna' do that? In the heat of the day? The fumes.... The danger involved of a spark setting things off, while you're crawling around, inside the battery bay? Call me crazy, but in my personal opinion, there are much more practical ways to float the bubble.... Like a few Honda portable gensets... | ||
| David Hartley (Drdave)
Rating: N/A |
"Term-Oh-Nuclear" meltdown... ( oxymoron ) | ||
| John MC9 Rating: N/A |
Well, ya' know... sometimes we get carried away, and overly intrigued with what we'd like to do, and what may be the outside edge of what's possible.... and forget the practical aspects of it all.. Being a busnut effects the entire family. Thank goodness there's medicine for it; comes in fifths, quarts and gallons. | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
David, The listed batteries are sealed lead acid batteries, not gel type. Wiring isn't a problem. I acutally like doing stuff like that. Some of my wiring will appear a bit insane when I'm done, but be above the requirements. John, I was going to get fancy with the actual mounting of the batteries. I was thinking of putting in rails on both sides, probably C shaped so the trays wouldn't be able to hop up over bumps. I'd then use some heavy duty rubber wheels, so they could roll out to access. I may get a bit fancer with them, if I can find the metal. I'd like a lip at the bottom, so the wheels are captive. Maintaince would be easy. Shut off the master breaker for a tray, disconnect it's main leads, release the pins holding the rack in place, slide the tray out, and check the batteries. It wouldn't even require shutting down all the electrical, just individual trays. Since they're sealed lead acid, I don't believe there's any inspection, other than checking each battery to make sure that they're still holding charges. Failed batteries would just need to be removed, and the space they occupied jumpered over until they can be replaced. I do a lot of computer work, and most of our better servers have slide out rails. Some of these machines are a couple hundred pounds, and slide out very nicely. I'll probably be stealing some design ideas from them. They use very lightweight metals that bend very easily in the wrong directions, but hold the servers fine in the right ones. I'm always surprised, when we slide out an 8U Dell server, and it doesn't go crashing to the ground. Their rail kits don't seem like they should hold up anything, much less a heavy server. I shouldn't have any real concerns over hydrogen buildup, if I don't enclose the areas. The batteries are sealed, but even so I'll be venting the area. I was thinking of some brushless vent fans, but it'll probably be a lot easier just to have good vent holes. I may just end up having a few blower fans providing positive pressure to blow out anything that may be inside. Exhaust fans would provide negative pressure, but they'd also be pulling any gases that may exist through the fans. In all, I'd like to be less dependant on gas or diesel. Rising costs, and the need to pull up camp and find a gas station would be nice to avoid. I'd prefer to be able to stay in camp for as long as possible, and just take the car to pick up supplies like food. Where I am now, it would be good if I could backfeed some power back into their system. I'm not against buying a large solar array or lots of batteries for one simple reason. Eventually, I'm bound to want to stop and settle down again. When I do, the solar panels and batteries would likely be moved over to run the house. And, yes they'd fit. It's not a final choice, but I've been looking at the Kyocera 190 watt solar panels. 56.2" L 39" W 1.4" D If I allowed for 7' across, and 30' long on the roof, I could arrange them 2x6 (12 panels), or 1x9 (9 panels) If I allowed for 7.5' x 35', I could do 2x7 (14 panels) or 1x10 (10 panels). 12 panels would provide 2.2Kw in peak sunlight. I was thinking of a multi-tiered panel scheme, so when parked I could slide two layers of panels to the left and right of the bus, and tilt the whole assembly towards the sun. Pretty easily, it'd be over 6Kw during peak sun. The panels would provide additional shade, so the air conditioners wouldn't need to work as hard anyways. The panels are pricy, but the way I look at it, with the bills to live in a brick and morter house in Los Angeles, I could easily afford 12 panels and the associated hardware after a couple months on the road. I say "on the road" as living in the bus full time, not actually driving around the whole time. Right now, I'm throwing all that money into rent, gas, power, water, land phones, internet, etc, etc. I'm already paying for cell phones, and cell internet (VZW), and VoIP phone, which does work over the VZW service and wireless networks. Phone and internet service on the road wouldn't be an additional bill. I'm trying to establish now what I'll be doing. If I won't run into weight problems with the batteries, and the partial charging scenerio won't hurt them, then I'll reserve space for them. I won't just be ordering them now, I'll do it when the bus is pretty much done, and even then, I'll probably drive out to the vendor to save a fortune in shipping. They'll just have to live with me putting them in, in their parking lot. | ||
| Gary Carter Rating: N/A |
Try and find you favorite medicine in any of the above quantities. Don't exist anymore. Try liters and you will have success. As far as the batteries go, I have 1300 amp hours of power divided by 1/2 gives me 650 useable. (12 T105s). I can suck them dry in a day and one/half with just a 20 cubic foot Amana refer, plus TV, etc. The problem is getting them charged up. My 2500 watt inverter has a 125 amp charger built in. This is not enough. Have 500 watts of solar on the roof. Not enough. Next step is adding a 150 amp altenator one the generator engine (26HP). According to Zantrex reps at FMCA you can charge with up to 1/4 the total amp hours or in my case 300 plus amps. I will have 275 available. I realize that at some point one will override the other, but at that point I will be close to full charge. | ||
| herman Rating: N/A |
So, between ~25 (6V batts, 24V system) and ~100 (12V batts, 12V system) parallel strings, eh? That equals a disaster waiting to happen. Go get a single string of Rolls / Surrettes: http://www.surrette.com/pdf/4ks25ps.pdf or http://www.surrette.com/pdf/2ks33ps.pdf can get em at: http://store.solar-electric.com/suprdecyba.html You can offset their higher costs with the reduction in life insurance premiums ;). | ||
| John MC9 Rating: N/A |
".....rails on both sides, probably C shaped ...... .....I'd like a lip at the bottom, so the wheels are captive.... " Typical garage door track and trolly assembly! "release the pins holding the rack in place, slide the tray out," You might want a motor to do that trick. You're talkin' HEAVY. "Since they're sealed lead acid, I don't believe there's any inspection" Is there any such thing as a "no maintenance" lead acid battery? They all require water refills.... It's a task for a few, a major project for 105. *In all, I'd like to be less dependant on gas or diesel. *the solar panels and batteries would likely be moved over to run the house. *the bills to live in a brick and morter house in Los Angeles, I could easily afford 12 panels *Right now, I'm throwing all that money into rent, gas, power, water, land phones, internet, etc, etc. We'd all like to be less dependent on the oil commodity folks. And the solar panels can be re-used, of course! I do find that comparing a home in LA, to living in a bus, a lil' disturbing..., at the least.......! The cost to "full time" has risen, due to the high rollers that insist on all the high end features of a major hotel. They fail to understand the concept of "camping", is to do without the features of a hot tub, horseback riding, and Polo. Nothing is impossible. You can have anything you want in life. I personally, would not want the pain of a chore, to keep an eye on 105 batteries. I'd much prefer to feed a generator gas, and so greatly simplify my life. Ya' see, man.... Camping's about simplification... The ease of which, we go though the hours of our life..... Whatever works fo' U, is good fo' U! (but maintaining 105 batteries? Whew!) | ||
| John MC9 Rating: N/A |
"You can offset their higher costs with the reduction in life insurance premiums " HAR!! Yeah... "till death do us part..." (holy *&^% , the prices!!!) | ||
| FAST FRED Rating: N/A |
"They fail to understand the concept of "camping", is to do without the features of a hot tub, horseback riding, and Polo" Polo is passe , just came back from surveying a boat at a fancy yard that has special 2 place carrages they use at competition events. All dressed up with the little hard black riders hats like English Gentlemen and all! The rate was $1.25 per foot per day (electric extra) with a 6 month winter "comittment " (you pay in advance) . Most of the tubs were 55 to 70 ft.They have a 4 year waiting list. Nice behind the electric gate , but not MY WAY! FAST FRED | ||
| Marc Boruget Rating: N/A |
Hard to arrange the cabling for such a large collection of batts. Keeping lengths equal, providing for slideout capability, expecting capacities to remain similar enough to avoid circular currents. How would you expect to equalize such a bank? Enough of a job if your "other time" was restricted like a parapalegic or a prison inmate. Think again on "efficiency" Anytime you generate the power internally to charge the batts you're doing it as an [expensive] convenience. You might consider Bob Belter's approach with dual [small and large, well silenced] gensets. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
With all those batteries, why would you consider running the generator full time. It would seem that 6-8 hours per day would be sufficient. Especially if you have adequate sized battery chargers. Richard | ||
| Tim James
Rating: N/A |
Check out the following link...it will answer all your questions about power consumtion with different scenarios. Also, probably the best designed bus electrical system I've seen. It uses golf cart batteries...cheap, long life, and dependable. http://www.purplebear.com/busnuts/bus_elec.html | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Man, what a great link. Jock should really be proud of himself. I seem to recall he may have other technical notes also and he used to post on the boards but I do not recall seeing him recently posting. Richard | ||
| herman Rating: N/A |
That would be because he died a ways back; couple years now, if memory serves me. | ||
| Ron Walker (Prevost82)
Rating: N/A |
I have to agree with Gary....I have around 3000 AH cap on my batteries and trying to run the A/C off the batteries (which will work) is not a good use of battery power, it takes way to long to recharge. Unlike Gary I run 2 DR2412 inverters so I get around 240 amp charge. So after running off the batteries all day and night it takes 2 to 3 hrs on the gen to bring the batteries back to full change. In my experience it's as much about the time it take to charge the batteries, with includes how much amps you can hit them with without destroying them, as it is the battery size and capacity. Ron | ||
| Crane Rating: N/A |
The problem we had at a power plant with 100 plus batteries was the tie straps. If we didn't have loading between cell problems, we had hot spots. You are talking a lot of cells to build the load capacity you need. I didn't see a voltage on the cells but guessing 24vdc, you still need to go series with a number of groups and then parallel those. You will have a lot of straps all over. I assume your bay is all metal to a strap fire won't burn your coach down. I used to think the fewer the cells the better but cost wise or weight wise, I guess we have to take what ever we can get and strive for the best storage system we can build. Take a good close look at how you would connect for your amp loadings and make sure there are no not spots. If the compartment is not all metal, plan on lining it with metal at least. good luck, just my thought | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Some of the equipment I used to manufacture used a 600 volt DC bus. This required 50 of the 12 volt batteries for each string. Sometimes as many as four strings for 200 batteries total. It was a lot of work maintaining the system with all the interconnects and the requirement to check water level regularly. Also had to check each individual battery in each string to make sure there was not a weak or bad cell in one string. Batteries were generally rated for a 10 year or 20 year life. One large set used individual 2 volt cells that had to be connected together and total power was 1,000,000 watts for 15 minutes. You never wanted to let the smoke out of a system like this. LOL Richard | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Richard, Never let the magic smoke out. God put it in there for a reason, it's not for us mortals to let it out. For some reason, every time I say something like that, I can feel a static charge building up, and I can hear thunderstorms rolling in. That, with no rainclouds in the sky. |