| Author | Message | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1205 Registered: 7-2006 Posted From: 74.162.95.33  Rating: N/A |
Ok.. a question for the power gurus. I just bought a SPT Portable Air Conditioner, 7500 BTUs to use in my E350 diesel van. It runs on 110vac, 600 watt. I had planned to use my Honda 2000w portable generator, but even better would be to use the 1,000w xantrex that came with the van. I'd install a battery bank for it specifically. The battery bank would be charged as I drive, with the AC unit being powered via the inverter using the van's system. But when we stop for shopping, eating, visiting, etc., I'd like to have the AC continue running without having to run the Honda generator. The question? How many batteries will I need to run the air conditioner for 1 hour; for four hours; for 8 hours? I'd prefer the coil batteries (no gassing), but I'm looking for the most bang for the buck.... (The formula is OK, but if anyone has personal experience, it'd be even better) Thanks in advance, John | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1367 Registered: 5-2001 Posted From: 65.74.67.148 Rating: |
John, 600 watts at 120 volts will be a little over five amps. Multiply by 11 to get the 12 volt amps of 55. This means that from a fully charged battery of 220 amp hours, you should get nearly 4 hours running time before they are fully discharged. If you want your batteries to last, you should avoid going much over two hours on batteries with the compressor running all the time. The above applies to two golf cart batteries. Increase the bank to four batteries for double the run time. I think that this may be the most bang for the buck that you can get with that setup. You probably don't want to recharge them any faster than you run them down. I hope that this is the kind of info that you were looking for. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1206 Registered: 7-2006 Posted From: 74.162.95.33 Rating: N/A |
That's exactly what I was after, Tom! I have the formula, and the info from xantrex says about the same thing. I doubt the AC unit would be running more than an hour at any given time anyway. Two 220 ah batteries should do well for me! We usually take our pets with us, and I want to make sure they don't cook in the van while we eat in some "greasy spoon". Running/idling the engine is reducing my mpg from 15-16 to around 12-13. And idling is annoying to most people down here... Thanks again Tom, you've given me the answer I needed! Stay well, John | ||
| Dave Walker (Chrome_dome)
Registered Member Username: Chrome_dome Post Number: 277 Registered: 3-2010 Posted From: 75.208.113.207  Rating: N/A |
But also remember that you don't want to fully discharge them ever. Only 20 % to 50 % Maximum. So you might need more or better batteries with more amp hours. FWIW Dave | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1507 Registered: 10-2006 Posted From: 76.195.79.115  Rating: N/A |
If the system is in use constantly it may never get "fully charged". In that case you will be living with 50% as a bottom and 85% charged as a top. So you will only at best get 35% of the amps in the house bank working for you. A much larger batt set would help as a 55A discharge will flatten a 220AH bank very rapidly , you wont the the amps output as if the discharge was a 10A rate. You might cut some of the inverter losses with a DC air cond unit, in this small size. FF | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1508 Registered: 10-2006 Posted From: 76.195.79.115 Rating: N/A |
A second thought is the inverter will work far better if it is a true sine wave unit, not a chop chop, which may not power the AC enough to get much cooling. FF | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1207 Registered: 7-2006 Posted From: 74.162.95.33 Rating: N/A |
Dave - Re: "you don't want to fully discharge them ever. Only 20 % to 50 % Maximum" Fred - ".....may never get "fully charged...... ...inverter will work far better if it is a true sine wave unit...." I have two inverters: The one that came with the van is a Xantrex 1kw 2kw peak, and a Harbor Freight 2kw, 4kw peak. Neither is a sine wave model, and I really can't afford to upgrade to one. I suppose I could try swapping both for one? In any case, the Xantrex will turn off if/when the power drops too low, so that should take care of the problem of draining down the batteries too much, right? (I hope?) I don't want to fill the van with batteries just to run an AC unit intermittently; it'd be overkill. I could run the 2kw Honda generator for far less money. Or for that matter, I could use the liquid cooled 6kw Honda I bought from Pete, back when I had the bus.... The idea of using a couple of batteries to keep the van cool between stops seemed like a nice, clean way to do it for now. If I ever convert the thing to a camper, I'll definitely use the genset. Thanks for the input guys! John | ||
| Dave Walker (Chrome_dome)
Registered Member Username: Chrome_dome Post Number: 278 Registered: 3-2010 Posted From: 75.208.100.222 Rating: N/A |
Another words if the inverter will keep up and set to only 20% Discharge and it starts charging again but at some point you would have to use another source to power the AC unit while it charges back up. You keep 80% or at the least 50% in them and never let them get any lower your batteries will last for a lot longer 5 to 8 years. I got US Extreme deep cycle Lead acid filled batteries @ 232 AH each. You might want sealed ones in a van or place in separate compartment. Dave | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1489 Registered: 7-2006 Posted From: 97.227.227.158  Rating: N/A |
Really good to see you back "in the groove", JTNG! RCB | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1368 Registered: 5-2001 Posted From: 65.74.67.148 Rating: N/A |
John, I'm sure that you already figured out that running a cord out to your van from your house was going to give you a chance to fully recharge overnight. If your alternator is more than 55 amps, I think that you will do fairly well with the setup. Good luck! Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska (Message edited by pvcces on May 02, 2011) | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1208 Registered: 7-2006 Posted From: 74.162.95.33 Rating: N/A |
Hey Chuck! Thanks. I'm not too sure if I'm "back in the groove" or not. but I'll tell ya' one thing....getting there is 1/2 the battle! I just spent Jan 28 to Feb 23, then Feb 28 'till March 9 in the hospital. They tried to fix an intestinal obstruction that formed due to the colon cancer operation I had back in 2006. They said it'd be a two hour operation and about a week in recovery. I had four operations, each about four hours duration, and ended up with 1/2 my small intestine gone. No matter what, don't go to the hospital for surgery. Have someone with a decent weed whacker do it for you. My insurance and Medicare paid for damn near all of it, but the co-pays and deductibles (and being retired) make buying batteries a bit more difficult. While I'm typing and maybe have a few people's attention, I have five OE tinted glass from the side windows of my former MC9. I posted then on Craigslist for too long, and they have to go. I'm moving out of the three storage bins we've had for years! Free to whoever picks them up, otherwise they're headed for the landfill; PM me. (I'm in Melbourne, Fl, by the way.) Thanks for all the input guys. I fired up the Xantrex, and will see if it powers up the AC unit and runs it for a few cycles tomorrow (I hope). If so (Dave), I may check the latest prices for deep cycle coil batteries and make an investment. There's an "International" battery company store in Melbourne, and they did carry "blemished" batteries at one time. They're about 1/2 the price of an "unblemished" battery. What the hell is a "blemished battery"? And why should I care if there's graffiti on the thing? I'll let youse guys know how I do. It may be weeks, however.... Thanks again! John | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 81 Registered: 11-2007 Posted From: 81.253.73.132 Rating: N/A |
Checking to see whether the 1kW inverter will actually start and run the AC will be the first step. I run a similar size split unit off batteries via a 1400W sinewave inverter and it is fine. Fully charged batteries (Big solar system) allow me to run the ac for several hours without running the batteries down below 50%. 24V system which keeps currents down compared to 12V | ||
| Dave Walker (Chrome_dome)
Registered Member Username: Chrome_dome Post Number: 282 Registered: 3-2010 Posted From: 75.210.54.208 Rating: N/A |
Laughing John about Graffiti, cute. Blemished (I am Guessing would be either seconds or returns that have been cleaned up and put back on shelf, used or something similar? Somewhere should know exactly what they are. There is a place here in Sacramento that rebuild old used up deep cycle bats which are pretty good. Dave | ||
| George Martinez (Foohorse)
Registered Member Username: Foohorse Post Number: 497 Registered: 1-2010 Posted From: 69.171.161.117  Rating: N/A |
John will those windows fit in my 4905?. | ||
| Dal Farnworth (Dallas)
Registered Member Username: Dallas Post Number: 519 Registered: 7-2004 Posted From: 75.91.203.25  Rating: N/A |
Sure they will Fooie! All you have to do is cut holes in the sides of the bus. | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 1370 Registered: 3-2007 Posted From: 71.55.178.71  Rating: N/A |
FOOY!! Stop by and pick up the one I have. Gomer | ||
| George Martinez (Foohorse)
Registered Member Username: Foohorse Post Number: 498 Registered: 1-2010 Posted From: 69.171.161.97 Rating: N/A |
On my return from Dust hell I will do that Marvin, But I believe my next stop will be In Pennsylvania to visit the Amish and get some wood and soul work done. Dallas I would like to keep the same size holes that are there now thank you, are you still seeing mystery Dillos that don't exist. now back to this topic I have a lead on gel batteries from cell towers I will post the specs when I get them. (Message edited by Foohorse on May 06, 2011) (Message edited by Foohorse on May 06, 2011) | ||
| PA Doug (Padoug)
Registered Member Username: Padoug Post Number: 37 Registered: 1-2009 Posted From: 71.61.46.228 Rating: N/A |
George, I sent you an E-mail. Doug |
