[Trickytrotter]

Sorry. I've been away on a car rally. Here's the costs I have so far...

Item	Cost (NZ$)	NZ$ to US$	Cost (US$)
1967 David Brown 880 Donor Tractor	2600.00	0.67	1742.00
QS-Motor QS-180 Motor & ND72850 Controller	2007.70	0.68	1360.00
Cycle Analyst CA3 for PTO	229.26	0.69	157.11
1-3/4" Pillow Block Bearing	82.00	0.69	56.58
7/8" Pillow Block Bearing	36.00	0.69	24.84
Golden Motor 10kW motor + VEC500 controller	3160.35	0.66	2085.83
Cycle Analyst CA3 for Transmission	338.14	0.64	215.13
Various Switches & 12V Relays	151.17	0.64	96.75
2x 300A Shunts	70.28	0.63	44.47
100Ohm 10W Precharge Resistors	20.91	0.62	12.87
10k Potentiometer (x10 turn) for PTO control throttle	11.22	0.61	18.39
2x 600A Main Contactors	228.99	0.61	140.76
Battery Cables (battery to contactor then to controller)	291.08	0.65	189.20
T10 Timing Belt Pulleys (x4)	477.71	0.64	304.78
T10 Timing Belt	36.89	0.62	22.89
T10 Timing Belt	48.22	0.62	29.92
Motor Brackets (custom design)	1008.55	0.62	625.30
Hall Effect Foot Controller	57.90	0.62	35.90
Hall Effect Angle Sensor for hand throttle	51.03	0.61	30.89
T10 Idler Pulley	20.43	0.54	11.03
Timing Belt Pulley Machining (splining)	1101.70	0.57	627.97
Misc Nuts, Bolts, cables, cable ties, etc	693.34	0.62 (avg)	429.87
Total	12,722.87		8,262.48

NB. The Golden Motor items were purchased via local NZ dealer, whereas the QS-Motor stuff was bought direct from QS-Motor in China. So, would probably have been cheaper if I purchased the Golden Motor stuff direct from China too.

In addition to the above, for testing I've also spent NZ$1,033 (=US$642) on 4x Trojan T-1275 batteries (2nd hand), 4x 12V battery chargers, a 4-way battery balancer and some 13pin plugs & sockets (to make connecting balancer or chargers easily).

Next big costs will be the final batteries needed, battery management system and charger.

Although, I'm not overly happy with the QS-180 motor & ND72850 controller. If the PTO's Golden Motor motor & controller turns out to be better (I've yet to test that under expected loads, but initial light load tests look good), I may buy another set to replace the QS-Motor ones. So, fair to say all the above costs are not final yet

Hope the above helps?

 

[electro wrks]

Although, I'm not overly happy with the QS-180 motor & ND72850 controller. If the PTO's Golden Motor motor & controller turns out to be better (I've yet to test that under expected loads, but initial light load tests look good), I may buy another set to replace the QS-Motor ones.

What's the problem with this motor/controller set-up?

 

[Trickytrotter]

What's the problem with this motor/controller set-up?

The QS-180 motor & ND72850 controller doesn't seem to have much low rpm torque, which makes the tractor quite sluggish when pulling away from a standstill. It's ok once you get moving a bit, so need to use the gears (but I think it would struggle pulling out a small tree stump ). I've played around with the controller programming settings, but none of the setting changes seem to make much difference (and there isn't a decent manual or information anywhere that explains what all the controller's settings do). The Golden Motor set-up seems to be better in this perspective, but I need to confirm with it under some higher loads. Plus, the QS-180 motor is quite noisy in comparison to the Golden Motor one too.

 

[electro wrks]

so need to use the gears

It sounds like you need a higher drive reduction ratio from the motor to the trans. input shaft, for the available power output of the motor. Roller chain drives are a lot cheaper and more convenient to use, initially, when trying to sort out the best ratio. Motor amp (or battery to controller amp) input figures would also be useful

Also, the 40HP rating for the ICE in the tractor is a typically a very conservative, continuous rating. This is compared to the continuous ~10HP rating, with ~20HP peak for some seconds or a few minutes for the electric motor. Limited motor output may be a factor.

 

[Trickytrotter]

It sounds like you need a higher drive reduction ratio from the motor to the trans. input shaft, for the available power output of the motor. Roller chain drives are a lot cheaper and more convenient to use, initially, when trying to sort out the best ratio.

Yes, good idea! Thanks for that.

Motor amp (or battery to controller amp) input figures would also be useful

Well, that's the thing. The amp draw (battery to controller) is quite low (20 to 40A) during start-off, but then raises to 80 to 100A once it gets moving (approx 1000 motor rpm). Btw, I have the controller limited to max 120A draw due to test batteries I'm using. As I say, I've been trying to tweak settings in the controller, but nothing has made much of a difference yet.

Also, the 40HP rating for the ICE in the tractor is a typically a very conservative, continuous rating. This is compared to the continuous ~10HP rating, with ~20HP peak for some seconds or a few minutes for the electric motor. Limited motor output may be a factor.

Yep, motor may be a tad small (as you mentioned in an earlier post ). More testing will confirm. Could perhaps double the motors up, but will likely get something bigger.

 

[electro wrks]

Well, that's the thing. The amp draw (battery to controller) is quite low (20 to 40A) during start-off, but then raises to 80 to 100A once it gets moving (approx 1000 motor rpm). Btw, I have the controller limited to max 120A draw due to test batteries I'm using. As I say, I've been trying to tweak settings in the controller, but nothing has made much of a difference yet.

You may be dropping down to the low voltage cut-off of the controller. Try some bigger batteries.

 

[Trickytrotter]

You may be dropping down to the low voltage cut-off of the controller. Try some bigger batteries.

I'll check again, but I never noticed a big voltage drop on the Cycle Analyst. Plus, I think the controller would stop the motor on low voltage, rather than reduce the amps, wouldn't it?

 

[ratchet6900]

Hey, just read up on your most interesting project - especially interesting to myself as I am contemplating a Yanmar 15HP diesel tractor conversion. As it so happens, I am looking at the Golden Motor 10 KW for the main drive (although it's a little light on torque compared to the diesel). As for hydraulics, my pump is driven directly by the engine so I would need a separate electric hydraulic pump (if I can find one that runs on 48V). I'm thinking of going with lead-acid as well as lithium can be a pain to deal with in cold weather and I don't need especially long run times.

I'm wondering though if the clutch should be left in place as the tractor's transmission is non-synchro and it is necessary sometimes to double clutch when switching gears (I'm not sure how that would work with a no clutch/elec motor setup).

I'm a bit surprised your QS motor has low starting torque - sounds like it may be a controller issue and, rather than replace the motor, maybe try a different controller brand. I mention that as I have a small electric quad on which I replaced the stock controller with a (programmable) Kelly unit and am very pleased with the results (excellent low range torque and smooth speed control).

Looking forward to hearing about further progress with your conversion!

 

[ratchet6900]

PS, have noticed the QS-180 motor is rated at 72 to 96V. Could this be an issue, particularly low torque, when operating with a 48V battery?

 

[remy_martian]

You've set your battery voltage, vs choosing a motor and battery voltage that work together.

Enjoy the pain from silly constraints.

 

[Trickytrotter]

Thanks, Guys. Yes, even though the QS-Motor's sales guy said the ND72850 and QS-180 would work ok at 48V, I do think it's more suited for 72V plus. Through tweaking controller settings I have managed to get it better than it was, but as the Golden Motor is working so well on the PTO (30A draw while running my 1.5m rotary slasher and hydraulics), my next step is to try the Golden Motor running the drive transmission and test that.

Btw, I've now completed a 10min mowing test run with the tractor and rotary slasher - results were:

1. PTO motor start and PTO shaft to 700RPM (2.6:1 so motor = 1820RPM), raise mower & lock* = 0.17Ah
2. PTO motor stop, Drive motor start and travel to paddock (approx 250m - High 3rd gear = 8km/h at avg 60A draw) = 1.90Ah
3. Start PTO motor, lower mower, start mower (PTO shaft to 1000RPM) then mow weeds in paddock for 4mins = 5.33Ahr (PTO avg 30A and Drive avg 50A in high 2nd gear, using eyeball on gauges)
4. Stop mower, raise & lock*, stop PTO motor aand then drive to shed and park = 2.10Ahr
Total = 9.50Ahr and approx 10mins running all up. (150Ahr Lead Acid batteries were probably getting near the max usable depth of discharge after that run).
*NB. The David Brown 880 has a lever to lock the hydraulic arms in the up position, so saves having to run the PTO motor to run the hydraulics while traveling to & from the paddock.

@ratchet6900 I am able to change gears, with a wee bit of crunching, by matching revs on up-change and blipping throttle on down-change - just like a crash gearbox in an old truck. Getting smoother doing it the more I'm getting used to it

My lead acid batteries (Trojan T-1275s) are just wet ones. If you use AGM or lead-carbon ones then you should get better capacity and depth of discharge, but I think I'll eventually go LiFePO4.

She's a fun project though

 

[ratchet6900]

Thank you for the update. I will be very interested to see how things perform with the Golden connect to the transmission (if it will perform well with your larger tractor, it should be extra fine for mine). Did you BTW see any motor heating problems with the Golden running the mower?

Not clear on your battery drawdown - the mowing session used 9.5 Ah but the 150 Ah batteries were almost depleted? Were batteries low when you started?

 

[Trickytrotter]

No heating issues - temps hardly moved (it was a 17degC day).

Not so much the draw-down on the battery (so my "depth of discharge" comment was probably a bit misleading, sorry), but rather the voltage dropping with the continuous 80A to 100A draw (got down to around 46V). Once I stopped the mower and was driving back to the shed the voltage rose a bit again (back to around 47V). So, I don't think my current batteries would do much more at the high load.

 

[electro wrks]

1. PTO motor start and PTO shaft to 700RPM (2.6:1 so motor = 1820RPM), raise mower & lock* = 0.17Ah
2. PTO motor stop, Drive motor start and travel to paddock (approx 250m - High 3rd gear = 8km/h at avg 60A draw) = 1.90Ah
3. Start PTO motor, lower mower, start mower (PTO shaft to 1000RPM) then mow weeds in paddock for 4mins = 5.33Ahr (PTO avg 30A and Drive avg 50A in high 2nd gear, using eyeball on gauges)
4. Stop mower, raise & lock*, stop PTO motor aand then drive to shed and park = 2.10Ahr
Total = 9.50Ahr and approx 10mins running all up. (150Ahr Lead Acid batteries were probably getting near the max usable depth of discharge after that run).

Are you sure your Amp and Amp-hour figures aren't off by a factor of 10? Something doesn't multiply out and add up with the size of the equipment used and the amount of power and energy used. 30A X 48V=1440W, about 2 HP. In my experence, that would barely be enough power to rotate a 1.5m(~60") rotary mower(if we are referring to the same type of mower), let alone mow with it.

 

[ratchet6900]

What about switching the transmission to reverse and vice versa (that's where I have to frequently double clutch)? I suppose though the best method would be to simply reverse the motor.

That much voltage drop for the draw you calculate seems quite excessive. Weak battery cell(s)? Might be an idea to measure individual battery voltages.

 

[remy_martian]

A tractor is not meant to be shifted on the fly...

 

[ratchet6900]

A tractor is not meant to be shifted on the fly...

Not moving when shifting forward/reverse. Still need to double clutch frequently.

 

[Trickytrotter]

Thanks everyone.

Let me double-check my Cycle Analyst settings - perhaps I have added the wrong shunt values.
Yes, my batteries are probably a bit suspect.

Not sure what you mean about needing to double-clutch when shifting from a forward gear to reverse, sorry. I just need to stop the tractor moving, drop the motor to zero RPM and then I can change gear from forward to reverse or vice versa without any issues.

Oops, didn't know about not shifting tractors on the fly. I do it on my Fergie 135 all the time - especially 2nd to 3rd, but also down shifting when I need to slow for bumps & corners. Maybe I shouldn't be...

 

[ratchet6900]

When shifting from forward to reverse (with tractor stopped), it doesn't grind but simply, about 1/2 the time, will not go into gear (the gearshift lever will move only a short distance. Double clutching almost always works the first time.

I suppose one could best & easiest just flip the motor forward/reverse switch - and gives the added benefit of having more reverse gears available (the YM155 has only two reverse gears, one usually too slow and the other often too high). Would be OK I guess as long as the PTO wasn't being used...

 

[remy_martian]

^^ I think it's a reason why Ferguson came up with the hydrostatic up/downshift (I forget the name...our 165 had it, my 65 and 135 do not).