inverter for 1500w air compressor
Submitted: Tuesday, Nov 04, 2003 at 16:18
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gunzo
hello
I own a HJ60 diesel landcrusier with a duel battery set up and do 99% of my 4x4 driving is on sand, accessing surfing and fishing locations between Hawks Nest and Forster (Myall lakes area) in NSW. On these regular weekend and holiday trips I will be on and off the sand 3 to 4 times a day.
My tyres are 16x285x75 and using my fathers $400 12v aircompressor the tyres take over 6mins each to pump from 12psi to 30psi , more than 25mins! each time off
the beach.
Looking at a 12v air compressor comparrison in 4x4 monthly, I noted that even a top of the range $1600 12v compressor will not peform much better...! Am I destined to spend hours each weekend I spend up the coast waiting for my tyres to inflate.?
I looked into endless airs "fan belt" driven compressor, this unit would pump my tyres up 10x faster than the best 12v compressor! and would price up at less than $1000 (unit +piping+tank+accessories) but install space is a problem with a/c , power steer,radiator reserve, etc and also a hassell to do myself.
So down to the local hardware I go and
check out the specs on some 1500w 240v 6 to 8 amp air compressors (only $150 ) and their cfm ratings suggest that these small 24L portable units will pump about 5 to 6 times faster than the $1000+ 12v compressors. and I can get a 1500w inverter for around $600 or a 2000w for 2 or 300 dollars more .
My questions are; 1) Will the batteries handle it.?
2) Will I have to keep the engin running?
3) The duel batteries have a 60amp isolator switch/(connector?),the amp draw will be around 135 amps from the compressormay be more, is this a problem.? as the alternator is probably only hooked up to the start battery and charges the secondary battery through the isolator(when switched"on")
4) Has anyone seen or installed a similar setup drawing this many amps/watts.? When I scearched the
forum on
inverters I could only find reference to low watt or long use items.
Any advice or coments would be much appreciated.
Thanks
Scott.
Reply By: GaryInOz (Vic) - Tuesday, Nov 04, 2003 at 16:45
Tuesday, Nov 04, 2003 at 16:45
Just a few random thoughts.....
Have you considered the possibility of using a 12 volt motor to drive the compressor? Something along the lines of a small winch motor?
It does seem pointless and very inefficient to go from 12 V to 240 V simply to turn a shaft to a compressor. The start up current on a typical 240 V motor is about 5 times its normal running current, and you would need to factor this in with your inverter choice. Sems like you are trying to spend big bucks to save yourself small bucks.
There are a selection of medium to larger 12V compressors available (one of whose name escapes me at the moment) which would seem to fill you needs. What you really need is a medium sized compressor connected to a 30-40 litre tank which gets filled as you are driving, rather than trying to generate large quantities of air at the time of airing up.
Other options...
Modify a "Christie" stationary generator by hanging the compressor directly on the front instead of the alternator.
AnswerID:
36197
Follow Up By: GaryInOz (Vic) - Tuesday, Nov 04, 2003 at 19:06
Tuesday, Nov 04, 2003 at 19:06
Ibelieve the name of the compressors was Clisbyavailable from Big Balls Offroad. Capable of decent L/min and quite quick.
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Follow Up By: GaryInOz (Vic) - Tuesday, Nov 04, 2003 at 19:19
Tuesday, Nov 04, 2003 at 19:19
The Clisby's are either 1/3 or 1/2 HP which equates to about 20-30 amp at 12 Volts. Much better than the 165 amp option and considerably smaller than CO2 tanks. At 55 secs from 8-35 psi in 55 secs I think that would answer your problems totally (5 mins to do all tyres).
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Follow Up By: GaryInOz (Vic) - Tuesday, Nov 04, 2003 at 19:22
Tuesday, Nov 04, 2003 at 19:22
I should proff read, err....proof read befor I post................
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Follow Up By: gunzo - Tuesday, Nov 04, 2003 at 20:50
Tuesday, Nov 04, 2003 at 20:50
the clisby soundes inpressive but im sceptical of the claim of a 35inch tyre inflated from 8 to 35 in 55 seconds withits 2.5cfm and 35 amps and at what pressure is the2.5 cfm delivered?
4x4 monthlys accesory gide compares 9 compressors, the best performers,(Flash air, Super pump and Twin tongue) all took over 2/12 minuts (over 150 seconds) on each 31x10.5x15inch tyre. 2 were JUST under in amps and cfm yet unlimited rating compared to 10 or 20 mins
on clisby. The Flash air unit tested at 3.12cfm@30psi and a wopping 65amp draw yet this unit also took over 2/12 mins. how can the clisbys performance be so much better????????????
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Reply By: chrisfrd - Wednesday, Nov 05, 2003 at 13:55
Wednesday, Nov 05, 2003 at 13:55
I have fitted an E-Air to an 80 series turbo-diesel for a club-mate of
mine.
We fabricated the brackets with a mate doing all the welding (electronics is my forte - not welding!) We removed the useless thermo-fan and fitted dual electric units (Davis-Craig) and re-engineered the whole belting system to attach the EA unit atop of the alternator, using an idle-pully and some tensioning points for two smaller belts to drive the alternator and EA unit.
All looks very nice, costed up to be around $300 in brackets, pully wheels, bearings and such.... And he is getting a 40L receiver made up that will bolt directly to the inside of the bullbar.
There's plenty of wasted space in those things. The thing I'm trying to get across is that there are many ways of skinning a cat, it's just a matter of practicing some basic engineering philosophies and making everything up to suit.
Personally, I would never carry cylinders and such, just because they are in the way, they are heavy, cumbersome and potentially stealable (if bolted to the spare wheel that is). KISS... That's the way.....
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Reply By: gunzo - Wednesday, Nov 05, 2003 at 23:37
Wednesday, Nov 05, 2003 at 23:37
Thanks for all the responses ,youve all talked me out of the inverter/240v compressor option.
Ive found the unit I think Ill go with from an old
forum posting, an Oasis 12v winchmotor connected to a auto air conditioner compressor (
york) and pumps a very respectable 9cfm @ 50psi (the 24v dose 17cfm @ 50psi) the amp draw however is 120 to 180 amps but as tyre inflation times will be dramaticaly reduced to less than 5 mins for all 4 tyres the load shouldnt be to much for the batery.
The unit costs around $1000 australian dollars. see
http://www.oasisoffroad.com/trailheadAirCompressor.html
and so far it is the only unit of its type ive been able to source (there in America)
I hope they can air freight me one , I called them this morning (in US) but there not available to contact till monday 10/11 (there at a trade show).
I called arb and opisite lock but they hadnt herd of this type of compressor
nor were they interested in helping me source one from Australia, dose anyone know of any retail
places in Australia who sell these powerful 12v compressors.?
Id rather buy in Australia if I could.
Also has anyone seen one of these things working? ,have a look at the site and tell me what you all think.
Thanks
scott
AnswerID:
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Follow Up By: Member - Bob - Thursday, Nov 06, 2003 at 11:25
Thursday, Nov 06, 2003 at 11:25
Gunzo,
Fedex or Express Mail for something as heavy as a compressor is going to be a lot of dollars. Also allow for customs fees and GST ($50 plus 10% of invoice cost). I'd be very surprised if you landed it for less than $1200.Bob
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Follow Up By: Brimo - Saturday, Nov 08, 2003 at 16:38
Saturday, Nov 08, 2003 at 16:38
120-180 amps for 5 mins! hope you have a bloody good battery and be sure to use some monster size cables and good quality connectors on the thing if you want to avoid a melt down. A smaller compressor and a receiver would save you a heap of hassle.
Regards
Brimo {a sparky who knows a bit about electricity:-) }
FollowupID:
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Reply By: Matt M - Thursday, Nov 06, 2003 at 18:12
Thursday, Nov 06, 2003 at 18:12
Sounds like alot of expense and alot of work, when a little petrol compressor would do the job nicely!!
Yeah they can be a little weightly but the most is the little briggs and stratton motor, the reservoir could even be mounted under the sill near the chassis rails and utilise a QD for the mounted motor and compressor? That way it could be semi mounted in the vehicle and removed when not needed. The air tanks could then also be fitted with a tyre valve fitting, so that they can be replenished when you can from a servo compressor, allowing a reserve supply on the vehicle even if the compressor isnt on board.
But it that is too much, fitting of one of the top heavy duty 12 pumps with the reservoirs mounted would allow for a large reserve capacity, this really being the problem with inflation times. Then the compressor, using a ARB cutout can just happily run away, topping up the tank when you are back on the road waiting for the next deflation/inflation!!
Its all about reserve capacity if the huge CFM pumps are out of the question, so look for tanks!!!!
Goodluck!
Matt.
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