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Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 9:42 am
by twiss
A full tank of petrol weighs about 130kg

6 optima yellow tops weight 159kg... so some increase but not too much!

Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 12:03 pm
by Anton
twiss wrote:Cheers!

as for the hydrogen, seems a bit ott... I'm good with a spanner or a soldering iron, I'm not really into gas and LPG.
Fairy nuff! I'd love to do a conversion myself, to something that's cheap to run. But everything I look at has massive downsides:

Biodisel made from local chip shop chip fat is out, because diesel engines weigh too much and ruin the offroad ability of a sammy (or so I'm told by diesel sammy owners).

Electric doesn't have much range, which isn't a problem until I want to drive to an offroad place and go offroading. The real problem, however, is the £££...

Hydrogen hydride tanks take up lots of room and, again, £££...

LPG is interesting until you look at the skyrocketing price of LPG. If a kit costs as little as £300, it'd still take me YEARS for that to pay me back, because I do so little milage and LPG prices are going up faster than petrol.

Ethanol would be the simplest to do, because I'd just have to mess with the carb (or EFI as/when I get it) but is it really cheaper than petrol in the long run? If I had a bigass field in which to grow my own corn, and a still to make the ethanol, then maybe. Otherwise, nope.

Mate, if leccy makes the most sense to you and your wallet, then go for it. And post pics/vids. :snap: ;)

Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 12:05 pm
by twiss
With electric, I can charge at home, drive to work, re-charge at work, then drive home and repeat.

I could take a genny with me to power it just on long journeys

Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 12:11 pm
by twiss
Handy update, had a chat with the facilities manager at my office... He has no objection to charging an EV here :)

Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 4:01 pm
by Tramp
Come on then..... I'm ready to see some project pictures! & you aren't seriously considering running the motor through water are you?

Re: Hybrid Conversion SJ

Posted: Fri Mar 16, 2012 7:40 pm
by justaddmud
can someone check my math here

a 30" tyre has a rolling radius of 7.84 feet per revolution of the shaft

that is 2.35 meters per revolution

lets say you have a gear ratio of 4:1 that would mean that ever revolution of the motor would move the vehicle 58cm so 1000 rpm would give you 580m a minute 2000 rpm would give 1160m a minute and 3000 rpm would give 1740meters per minute

1740 meters a minute computes to 65.2mph (1740meters a minute, multiplied by 60 gives you 104400 meters an hour, 104 KPH)

Torque, you mentioned 130 lb/f using that same 4:1 gear reduction that is 520lb/f at the wheels

Surely that must be enough to move a 1000kg sj?

of course, my maths could be well out

and the 4:1 is fairly normal, 3.7 diff 0.3 transfer box

like i said i could be wrong, and have missed something, i just see adding a gearbox and a clutch as something of a waist, loss of power in the box, loss of energy spinning the flywheel, extra weight (ok not much) and extra complication

Works for the tesla, that has no gearbox (i think) and yes, ok, the motor is probably more than £1500 but that does 0-110 in one gear

Re: Hybrid Conversion SJ

Posted: Sat Mar 17, 2012 1:18 am
by twiss
I just don't think it will be as good to drive either. Having gears is good to get different amounts of torque and hp out of the engine.
I think it would be rubbish to drive with no box, and looking at the pic I posted with the green motor its so easy to fit to a gearbox...
I think it would be easier to use a gearbox than to rig it up without the gearbox ;)

Re: Hybrid Conversion SJ

Posted: Sat Mar 17, 2012 3:29 am
by Tramp
As just add mud said, spinning a fly wheel would be a waste as you don't need to keep the momentum for an engine, you may as well have as much machined off it as possible, you won't need the inertia from it really, it will just slow the acceleration

Re: Hybrid Conversion SJ

Posted: Sat Mar 17, 2012 11:43 am
by twiss
Yeah I see the point about the flywheel weight... less weight is good
Although to be honest its not one of my primary concerns!

As long as it can get to work on a charge that fine with me ;)
Getting the flywheel lightened would be something I would do... but I would probably do it with a standard flywheel to begin with, then lighten a different one and fit it later
keeps the initial costs down as everything is quite expensive ;)

Re: Hybrid Conversion SJ

Posted: Sun Mar 18, 2012 11:07 am
by parrotveasey81
twiss wrote:A full tank of petrol weighs about 130kg

6 optima yellow tops weight 159kg... so some increase but not too much!
:er: how big is your petrol tank :er:

my yellow top battrey waighs 19.8kg so times that by 6 and you get 118.8kg's