# Electric crawler



## Dustin_mud (May 22, 2012)

Need some advice on building a Ev rock crawler, for those who don't know what crawling is its a form of off roading by taking a 4x4 up steep technical climbs, if need do a YouTube search for it. Mine will start out as a jeep wrangler, what I need to know is what's the best setup? This will not see any road use and not need to go over 40mph and not many miles but will need to hold a charg for a hole day of climbing. The tires will be 37 to 40in tall and axle gears of 7:17, not sure how how much gearing I will need for a electric motor.


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## Dustin_mud (May 22, 2012)

A few samples of what im talking about, power isnt that important with the gearing so low. All of those pics were with them idelling up the rocks for the most part


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## Woodsmith (Jun 5, 2008)

I would imagine a large diameter series DC motor for the low down torque.

Your axle ratio, is that 7.17:1 or 7t pinion 17t ring? 
I think 7.17:1 ratio.
With 40" tyres and the transmission in direct drive top gear you will get 16.6mph per 1000rpm.
A large motor may be comfortable with 3000 rpm giving you 49.8mph.

What sort of transmission are you planning on using? Do you know what the ratios are in it?


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## Dustin_mud (May 22, 2012)

Yes it's 7.17 to 1, on the trans that's where I'm stuck. Didn't know if I could run no trans into a transfer case with a 4.7 to 1 low range or I could stick a Toyota 5sp in front of that with a 3.95 1st gear.


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## Dustin_mud (May 22, 2012)

These rigs use very little power, the green one is a Suzuki with a 1.3 that only put out 80hp new. It's all about the gearing, will it be the same with a electric motor?


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## Dustin_mud (May 22, 2012)

Also what kind of batt pack am I looking at with that setup? I have to use sealed batts do to the amount of time they spend on the roofs. LOL


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## Woodsmith (Jun 5, 2008)

I think you will need some sort of transmission. The problem will be that you want it very slow when rock crawling but fast enough on the flat to get from one rock to another. Gears will give you that.

The motor could pull from 1rpm but it will be inefficient, get hot and sap your range. Better to have a low gear and low transfer ratio to the axle I think. Then you can go to higher gears for running about.

Just adding a 4.7:1 transfer box drops your speed to 3.5mph per 1000 rpm, 10.6mph at 3000rpm. My EV tractor tops out at 7mph in top gear for comparison, could do with being a bit faster though.

Adding a 3.95:1 toyota gear in the transmission gives you 0.9mph per 1000rpm, 2.7mph at 300rpm.

How low do you want to go?

Sealed batteries are a must, depends on your budget and vehicle weight but a lithium pack will give you better power, range and less weight then lead gel batteries.

It would be really difficult to determine how long you can play for. The load on the motor and battery pack will be so dependent on how rocky the rocks are, how slow you are driving, how far you drive it between rocks, how long you park up while others play, etc.


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## Dustin_mud (May 22, 2012)

That's my worrie, how fast I'll run out of power. For the most part the trail will be less then few hundred yards of all rock but you sit a lot and maybe put 20miles a day on your rig and that would be a hell of a long day of wheeling.


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## dladd (Jun 1, 2011)

how many gallons of gas do you typically use? That could at least be a starting point, going on the 'rule of thumb' of 8kwh/gallon.

not sure how well that would translate to rock crawling, but it's a start.


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## Dustin_mud (May 22, 2012)

Maybe 5 gallons, with a gas motor my rig would be around 3200 pounds


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## Dustin_mud (May 22, 2012)

Is there any forklift motors that would work? I want to make sure this will even crawl and climb before I throw 10 to 15k in drivetrain


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## ruckus (Apr 15, 2009)

When you say forklift motor, I assume you mean series wound DC? These produce excellent low speed torque and should work very well in a crawler. I agree that you should use a tranny. It is much better to have gears you rarely use than to be limited in either torque or speed. This will also allow you to spec a much smaller and lighter motor. Saving more weight for batts.

The HUGE advantage of an electric crawler is you won't need to clutch to stop and start. You will be able to use your left foot on the brake and the right on the gas. One disadvantage of the series wound motor is the lack of regenerative braking. This means it won't hold you back on the downhills. AT ALL. If you want it to feel like a combustion engine with compression braking you will want AC or BLDC or Sepex which have regen which will hold you back on the hills.

As for range, one option is to bring a very tiny generator with you like those suitcase Hondas. They are super quiet and could power a small charger. This would allow you to charge while waiting for others or at the end of the day while camping, or on very long trips. 

Regardless of the motor you choose, I HIGHLY recommend you have the flywheel and coupler balanced. That will allow you to nicely spool up to 5000+ rpm without annoying vibrations.

Here is a chart of several motors (the last 2 on the list are 8" and 9"). You can see the tq they produce. You can compare this directly to gas motors except they don't need to "rev" to get that torque.
http://www.evparts.com/cms/picts/products/mt2120peakmotoroutput.PDF

Cheers.


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## Dustin_mud (May 22, 2012)

Wow thanks for that info!


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## Arlo (Dec 27, 2009)

Im supprised no one posted about Rock Dawg! Or Green Dawg.
http://www.youtube.com/watch?v=EmzVWEAD6wA


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## Dustin_mud (May 22, 2012)

Yeah I have seen that rig, wanting to build something more usefull. Don't get me wrong that thing is wild just more of a gimmick then a trail rig. What does a lithium pack cost, I know it depends on the size of pack but just a ballpark number.


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## mizlplix (May 1, 2011)

Lithium batteries cost about $1.25/ per Amp Hr. My car has 38--130AH cells for a 130 volt pack. 38 X 130 = 4940

4940 X 1.25 = $6,175.00

Plus shipping, 

This pack weighs in at 440 Lbs.
My motor weighs in at 125 Lbs.
My trans weighs 75 Lbs.

You get the picture. Plus you get to distribute the cells around to balance out the chassis corner weights.

Gearing....Gear it like you would do a Diesel engine and you would be close.

If you do not drive any roads, you can just gear it one speed, use a switch for for and rev. 

The transfer case has low/high to get you down slow....

Miz


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## Dustin_mud (May 22, 2012)

Looks like I'm going to stick with sealed lead batts. Lol


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## JRP3 (Mar 7, 2008)

You might not get the range, and they won't last as long. Over time lithium is more cost effective.


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## Dustin_mud (May 22, 2012)

Well I would like to test all of this before dropping 6k in just batts, if I knew this is going to work great then no problem.


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## ruckus (Apr 15, 2009)

roughly $1.5/kilowatt hour/ battery. So a 20ah batt costs $30. Of course, at 3.2v each you would need 38 to get 120v. So that is $1100 for 120v 20ah. Now multiply. You want 100ah? $5500 etc..


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## Dustin_mud (May 22, 2012)

ruckus said:


> roughly $1.5/kilowatt hour/ battery. So a 20ah batt costs $30. Of course, at 3.2v each you would need 38 to get 120v. So that is $1100 for 120v 20ah. Now multiply. You want 100ah? $5500 etc..


I'm just a simple gear nut, you just talked over my head. Sorry I am trying to learn, but as of right now I'm not sure what amount of V or Ah I want or need.


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## ruckus (Apr 15, 2009)

Just so you know, I am currently building a FJ-55 with full 2x6 rocker sliders and 2x4 quarter panel guards. 36" Swampers and airbag lift. So I know exactly what you are after. Step 1 was cut cut cut..

It's pretty simple. 1 amp hour will give you 1 amp for an hour. So a 40ah cell will give you 40 amps for an hour. Then it is dead. Pay attention cause this is most important. AMPS X VOLTS = WATTS. This is most useful because watts is like hp. Each lithium battery is 3.2 volts. That means a 40ah batt puts out about 120watts for an hour. 700 watts is about 1 hp. so 120 is nothing.

I gave you the chart of motor torque at 120v. To get 120v you need 38 lithium batts (3.2v each). It doesn't matter whether they are 10ah or 200ah, you still need 38 to get to 120v. Most lithium batts are good for 3-5C. C is the current rating. A 40ah battery is 40ah at 1C. If that batt is rated at 10C max pulse current, then the max it can put out is 400 amps. If you have a 1000 amp controller, then this is too small a batt. 100ah @ 10C is 1000amps. this is really hard on the batts. But for a 200ah batt 1000amps is only 5c. That is much nicer. So you want big batts. Problem is big batts take up a lot of space and cost money.

So the other way is to go high voltage. if you want a given amount of power (say 80 hp) that is about 60,000 watts. Divide that by 120v and you need 500 amps. but if the system is 240v you only need 250amps. Same amount of power. Thats because AMPS X VOLTS = WATTS

So if you want to be nice to your batts and not go over 3C then if you need 60kw at 120v you will need 38 160-180ah batts. But if you go to 240v then you need 75 80-100ah batts. Same amount of power, different configuration.

AC motors (which have regen or downhill resistance) tend to like higher voltages. DC motors (which have no downhill resistance) tend to like lower voltages. So you will pick a motor first, then spec batteries to power that motor.

Later...


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## Dustin_mud (May 22, 2012)

Thank you again for great info


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## Yabert (Feb 7, 2010)

Dustin_mud said:


> Well I would like to test all of this before dropping 6k in just batts, if I knew this is going to work great then no problem.


You can also test with small lithium pack.
With high discharge rate cells, you can build a small and lightweight pack for less than 1000$. The range (or the time between charge) will be also small but they can weight less than 100 lbs.

I think a used forklift motor is the best way for you because they can be find from free to 500$ and output more than 300 lbs-ft of torque from 0 rpm with a proper controller. I talk about 11'' forklift motor.


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## dladd (Jun 1, 2011)

I don't know a lot about rockcrawling, but it looks to me like a high torque motor is not really required, as referenced by the samurai 80hp engine. I'd look into one of the HPEV AC motors. you'd get a sweet smooth motor, regenerative braking, lower voltages, and probably plenty of power if you're geared down enough. 120v of 200ah cells may do it? I don't think you need high C rates, you need kWh.


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## Dustin_mud (May 22, 2012)

I like the thought of high volts and half the amps, so I could run smaller batts and shave some fat.


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## JRP3 (Mar 7, 2008)

KWh's = Volts x amp hours, so many small batteries or fewer large batteries weigh the same in the end for the same amount of KWh's, which equals range. No fat shaving


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## Dustin_mud (May 22, 2012)

Ok if I look into sealed lead batt how do I do the math for those, same way? Is cranking amps just the amps you plug into the formula? Sorry for all the newbie stupid questions, but trust me theres a ton more. Lol


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## PStechPaul (May 1, 2012)

I think the CCA of a battery is just about absolute maximum that can be sustained for 5-10 seconds, and is about 5 to 10 times the nominal A-H rating. So a 90 A-H battery might have a CCA rating of 600 amps, but that should be only for occasional use. Generally about 1/2 the A-H rating is about the maximum you want to sustain for any period of time, so figure 45 amps. And even that may only last about an hour. You can get close to the full A-H capacity at about 1/10 C, so maybe 9 amps for 10 hours. Lithium and NiMH can do better.

It seems that the "Green Dawg" or "Rock Dawg" uses just a 10HP electric motor which can give short bursts up to 40HP for 5 seconds, so for that you would need 30kW for 5/3600 hr or 167 W-h. You can get an honest 50 A-h and 600 W-h from a single battery, but you must figure the peak power. 30kW is 2500 amps. But you don't really need that much HP if you are going slow, so you might need to start with the total torque you need. You want to be able to essentially climb a vertical wall so you need a total force equal to the weight of the crawler and passenger. Let's say 1000 pounds. With 24" tires that is 1000 lb-ft. 60 RPM will give you a speed of about (24*3)/5280 miles/minute or 0.8 MPH. The power needed is 1000*60/5252 = 11.4 HP. Half that on a 100% slope (45 degrees).

So if you can be satisfied with about 1 MPH on a 100% slope then a 5 HP motor will do. That's about 3.8 kW and you want to limit battery current to about 100 amps, so you need 38 volts, or three batteries in series. If your non-climbing travel is fairly level, and no more than 10-15 MPH, you can probably do that using an average of 2-3 HP. Worst case, the batteries should give you 1800 W-H which is enough for about an hour, or 10-15 miles before charging, except for what you use when climbing.

It may be a good idea to use hydraulic motors in all four wheels, as the "Green Dawg" seems to have. That will give you 4WD without CV joints or U-joints. You might be able to scrounge some hydraulic stuff from garden tractors. Hydraulic drive gives you very precise control and excellent hill-holding ability.

Just some ideas, but I think you could put something together for under $2000 if you can do the work and get parts from a junkyard. You might be able to use a three-phase motor and a VF control, and power it from a 3000W 240V inverter, although you'd probably need to wire the batteries in parallel to get 12VDC at 250A. Otherwise, you can use twenty smaller batteries to get 240 VDC at 15A, or 30 batteries to get 360 VDC at 10A.

Good luck! Seems like a pretty cool sport.


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## JRP3 (Mar 7, 2008)

Here's a real world data point that might be useful. My 6 wheeler weighs around 700lbs, with a trailer loaded with around 400lbs of stone or wood, total 1100lbs, I almost stall out going up about a 45 degree hill. I'm running a 400 amp controller at 48V, so about 19KW, or 25HP, and I'm geared 16:1 overall and unloaded top speed is around 20mph.


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## Dustin_mud (May 22, 2012)

Ok now onto shopping for a motor, on the forklift motors I have read I need one around 9in and 150 pounds. What I haven't read is the specs, what kind of volt and amp? On ebay that's how they are listing them not by pounds and size. Next is controller, what am I looking for in one?


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## JRP3 (Mar 7, 2008)

They are probably going to be 48 Volt motors, make sure they are series DC, not Sepex or shunt. You should probably start reading the Forklift motor thread in the motor section.


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## ruckus (Apr 15, 2009)

What is your main concern? Price? 
Please remember that series DC motor will have NO braking on downhills. Are you ok with that? Happy to use JUST brakes? Ok, then consider series DC motors. Otherwise, you want BDLC or AC or Sepex. They are ONLY motors which give "compression braking" by use of "regen".

You must choose motor before controller... 

Cheers


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## Dustin_mud (May 22, 2012)

Very much ok with a Dc and having to brake, as far as money I want to make sure it's going to work well first then upgrade as I learn more.


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Very much ok with a Dc and having to brake, as far as money I want to make sure it's going to work well first then upgrade as I learn more.


Not sure you get it. Electric motors "work" that's why industry uses them. Choose the motor that is best for the job. Otherwise you give them a bad name and suffer disappointment. There is no "upgrade". You would have to redesign the entire machine. Get the best for what you want to do from the start or you will pay and suffer.

When you pick a motor you then design the battery and controller to fit that motor. The charger is designed to fit the battery that is fit for that motor. So if you pick a crap motor you pick a crap everything.

Do it right. Figure what you want, then find it, then spec each piece to be compatible. Simple. There is no "upgrade". PM me if you want private consultation on what is best for a crawler build. I am VERY familiar with the needs and can spec components accordingly. Scouts, Jeeps, Willys, Cruisers, I have done them all. Big tires, super flex, etc. etc.


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## PStechPaul (May 1, 2012)

I'm glad you can offer some real world experience and knowledge about this project. I found it interesting and I tried to offer my own ideas, but my practical experience is very limited. It's not a big deal if something does not work properly on my simple tractor project, with a total cost of about $300, and mostly parts I purchased previously. But it's a learning experience for me, and I will use that to scale up to a larger tractor and maybe a roadworthy EV.

But I can tell that the OP does not have the experience and basic knowledge of electricity and motors, and may make some errors that could prove costly and even dangerous. I'd like to learn more about this sport and it would be cool to follow the project as it progresses to design, prototyping, and field testing. But I think it will be difficult and hazardous to negotiate steep rock formations without good control, and the lack of "compression braking" might be a nasty surprise. Switching back and forth from the accelerator to the brake does not sound like a good thing. And without true all-wheel-drive, a series-wound motor might spin any wheel that leaves the ground.


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## JRP3 (Mar 7, 2008)

I don't agree that you can't upgrade a system, people do it all the time. I plan on doing it with my AC system, going from a 550 amp max controller to a 650 amp max controller, or maybe going with a higher voltage controller and adding more cells. The higher amp controller requires no other changes.


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## Dustin_mud (May 22, 2012)

I understand that electric motors "work", maybe that was the wrong word to use. I guess what I mean will it be practical in the real world. I will shoot you a pm, a shopping list will help out a lot.


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## Dustin_mud (May 22, 2012)

PStechPaul said:


> I'm glad you can offer some real world experience and knowledge about this project. I found it interesting and I tried to offer my own ideas, but my practical experience is very limited. It's not a big deal if something does not work properly on my simple tractor project, with a total cost of about $300, and mostly parts I purchased previously. But it's a learning experience for me, and I will use that to scale up to a larger tractor and maybe a roadworthy EV.
> 
> But I can tell that the OP does not have the experience and basic knowledge of electricity and motors, and may make some errors that could prove costly and even dangerous. I'd like to learn more about this sport and it would be cool to follow the project as it progresses to design, prototyping, and field testing. But I think it will be difficult and hazardous to negotiate steep rock formations without good control, and the lack of "compression braking" might be a nasty surprise. Switching back and forth from the accelerator to the brake does not sound like a good thing. And without true all-wheel-drive, a series-wound motor might spin any wheel that leaves the ground.


With my driving style I never really use compressing braking, I like to controll my rate of desint. With gearing so low and grate so steep if you rely on your motor it can easily roll you over. As far as a wheel leaving the ground is not a problem, you couldn't do the trails without having both axles fully locked.


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## Dustin_mud (May 22, 2012)

ruckus said:


> Not sure you get it. Electric motors "work" that's why industry uses them. Choose the motor that is best for the job. Otherwise you give them a bad name and suffer disappointment. There is no "upgrade". You would have to redesign the entire machine. Get the best for what you want to do from the start or you will pay and suffer.
> 
> When you pick a motor you then design the battery and controller to fit that motor. The charger is designed to fit the battery that is fit for that motor. So if you pick a crap motor you pick a crap everything.
> 
> Do it right. Figure what you want, then find it, then spec each piece to be compatible. Simple. There is no "upgrade". PM me if you want private consultation on what is best for a crawler build. I am VERY familiar with the needs and can spec components accordingly. Scouts, Jeeps, Willys, Cruisers, I have done them all. Big tires, super flex, etc. etc.


How would you go about building it, what's the best parts for the job? Thank you


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## ruckus (Apr 15, 2009)

Well, there are several routes. Here is one:
Brushed DC motor. A 9" motor @ 120v will give you 225 ft lbs @ 900 amps. Increase the volts and you will have more. More amps just tends to fry stuff. If you don't think 230ftlbs is enough, go with an 11" motor which will put out about 320ftlbs at the same voltage and amps.  Here is a good link with info on the motors:
http://www.evsource.com/tls_warp9.php
Just remember the larger motor is also 83lbs heavier. I would like to see that weight in batteries. 

Speaking of batts, more is better, and bigger is better. So basically bend your budget over and get all you can. The voltage will sag under load and as they empty. So assuming you want the power levels described at 120v at the END of the drive you will need to start with a bit more. So lets say you go with 40 batts. 40 batts will go up to 146v when charged, and will be about 114 when empty. So for most of your range you will get 120v power levels or above. Bigger batts will have to work less to make the same current. So if you want 900amps then that would be 9C from a 100ah battery but only 4.25C from a 200ah batt. Higher C rates are hard on the batts and cause shorter cycle life and more voltage drop. If you find yourself trying to skimp on the batts, then you might want to consider going to a bigger motor as it will need less amps to make the same torque. This will be easier on the batts. You can probably figure on 3-500lbs of batts at a cost of $4-10K, depending on what you go with.

As for controllers, don't try to save $200 and end up with a nightmare. Go with a reputable controller such as Zilla, Soliton Jr., or Netgain. I have seen Curtis burst into flames after 50'.

So your laundry list should look like this:
Motor $1700-3000
Controller $2000-3000
Batts $5000-10,000
Charger $500
Everything else $1000-1500

Total $10,000-20,000 

Don't forget the 1500 watt generator so you never get stranded.


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## Dustin_mud (May 22, 2012)

Your talking lithium batts?


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Your talking lithium batts?


What other kind of batts are there?


Unless you are talking about those worthless lead weights formerly known as batteries which put out hardly any power and then go kaput. 

If you are into crawlers you know weight is a huge factor. Heavy vehicles just can't climb straight up like light ones. 

You want light. Lithium is light. Using CALB as a baseline, for 40 batts you are talking 300lbs for 100ah and 500lbs for 180ah.

That amount of voltage in lead would be about 1,500lbs!! 

Don't forget they would have 1/8 the life, 1/3 the range, suffer terrible voltage sag and not put out 1000amps ever. They would make your project a big bummer.

If you are considering lead batteries. STOP. Do more research. You will see that they are actually More expensive. Especially when you consider that you would need costly agm sealed batteries because you will spend time on the lid. You would be better off spending the same amount of money and buying a TINY lithium pack that you flog.
http://e-vconcepts.com/Lithiumvslead.html
Even with careful maintenance the lead was DEAD after 2 years.
The same dollars in lithium is still going strong 5 years later. The lithium pack was horribly undersized (to be the same dollar amount) and still completely outperformed the lead in terms of range and power and life.

Lead is dead my friend. RIP


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## ruckus (Apr 15, 2009)

Just to give some solid numbers:

Here is a 65ah lead batt that weighs 59lbs and costs $336. Please note that 65ah rating is only if you TRICKLE the juice out over 10 hours. They won't even tell you what the real ah rating is because it is so pathetic. $5.17/ah but those aren't even real amp hours. 144v pack weighs 708lbs and costs $4,035 and has a max of 500 cycles, but more likely only 200. If you push them, less. $8/cycle if you are very optimistic about their life.
http://www.batteryprice.com/odysseypc1700tbattery.aspx

Here is a 70ah Lithium batt that weighs 22lbs (it takes 4 to make 12 volts). and costs $378 (again, 4 of them). Not only is it rated at 70ah, but it can and will put out 10 times that amount (700amps). $5.40/ah (real amp hours). 144v pack weighs 248lbs and costs $4,252. Life is 2000+ cycles. $2.13/cycle.
http://www.evsource.com/tls_lithium_calb.php


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## Dustin_mud (May 22, 2012)

Well it sure seems like you know your stuff, and one hell of a sales man. Lol


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## Dustin_mud (May 22, 2012)

Here's one for you, can you run the motor as the batts charg? I'm going to guess no.


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## onegreenev (May 18, 2012)

Dustin_mud said:


> Here's one for you, can you run the motor as the batts charg? I'm going to guess no.


Yes but only with an external source like a gas generator. Not really worth carrying around. You would still need to stop and charge up even with an external generator. A generator can't provide enough to charge and drive for long. Best to just increase your battery capacity. 

Oh yeah! Get with those A123 cells and build a kick butt pack and have a fun car as well. If you must go with less AH because of budget then go with the A123 cells as they can really pump out the power vs other low AH cells. 

Pete 

With A123 Cells there is no need to compromise power or fun with a small AH pack of cells.


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## Dustin_mud (May 22, 2012)

Was just thinking since I have to buy a generator anyways could I have it on me incase I wanted a few more hours on the trail. Was just a thought


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## onegreenev (May 18, 2012)

CALB cells are good too. But for raw power go with the A123. If you don't think you can build a pack then go with CALB. Damn nice cells. 

Ruckus, 
I like your post above on comparing lead vs lithium. Pretty much a no brainer. I think I will incorporate that into my diddy on the benefits of electric vs lead acid vs gas. I like it. Thanks a bunch. 

Pete


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## onegreenev (May 18, 2012)

The thought process is fine but the process of implementing successfully is far more complex. Best to stick with cells and a charger and just drive within the range of the car. 
That is what I do. I drive a Leaf daily. It is my commute car. I just stick within its range and I am a happy camper. 

Pete


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Here's one for you, can you run the motor as the batts charg? I'm going to guess no.


Yep. So if you had a 1500watt generator and a 1500watt 110v ac charger then you would "plug in" to the generator. There is some loss going from dc to ac and back to dc, but that allows you to use a standard generator and charger and you can plug in other power tools or lights too.

Running with the generator on would be "hybrid" mode. This would extend the range considerably. Depending on your exact voltage and charger used, you would be adding about 8-30 amps. Run it for an hour and that is 8-30 amp hours added to the pack. 

Lets pretend you have 100ah batts and 144v system. Multiply those together and divide by 1000 to get kwh (14.4kwh). Now you only want to use about 75% which is about 11kw. Now lets say you want to run a trail that is a bit long and would require 15kw. You need 4kw. 8amps x 144v = 1.1kw lets call it 1kw. So the generator would have to run for 4 hours during the run. If you had a 4kw charger and a 4kw generator it would only need one hour.

On the whole though, it would be far better to put in more and bigger batts and skip the whole generator thing. Just the sound of rubber on rocks would be very nice!

I gain nothing by "selling" you on the price and performance advantage of Lithium. But every lead vehicle out there gives all electric cars a bad name. Proving to everyone that they suck. This is so ingrained in people that when you talk about electric cars they keep asking about all the extra weight. What extra weight? I ask. 

v-8=550lbs
radiator=60lbs (with water)
20gal fuel tank= 250lbs
exhaust pipe (if you have one) = 90lbs
lead starting batt= 60lbs
Oil cooler = 10lbs

Total = ~900-1000lbs

100ah batts @ 144v = 317 lbs
11" motor = 230 lbs
charger = 14 lbs
Controller = 50 lbs
Wire = 50 lbs
misc = 20 lbs
dc-dc converter = 10 lbs

Total = ~700lbs or almost 600lbs with the 9" motor!

Hmmm.. So lets see, MORE torque from 0 rpm with no clutching AND its 300-400lbs LIGHTER? That sounds like some big EV grins to me. 

THAT is the kind of performance that will have all the petroleum-exploders drooling in awe and build a future for EV's.


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## ruckus (Apr 15, 2009)

OneGreen is right about the generator just being a trickle unless you got a large one and a large charger. It is an interesting notion though to be able to charge up overnight while camping or to increase the length of the run. Since crawling tends to have a lot of down time while waiting for others to clear obstacles, this could mean you drive silent but sit noisy.

My guess is once you drive a "silent" vehicle you will hate the sound of the generator. 

A 1500w generator is about 50-70 lbs..


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## PStechPaul (May 1, 2012)

I think your cost for the lead-acid battery is a bit high. Here is a 105 A-H deep cycle battery with 550 CCA for $85:
http://www.tractorsupply.com/stowaway-battery-st27dc180-4001105
It weighs 62 lb, so that's about 1200 W-H and about 19 W-H/lb, and less than $1/A-H. So the Lithium cells would have to be five times "better" for cost parity. 

For a rock crawler, you don't really need a lot of power, or long running time. It might be possible to make the vehicle with easy-swap modules of four batteries each for 4800 W-H which could provide 550 CCA (at which point the voltage will be about 1/2), so about 13 kW or 18 HP peak for about 10 seconds. You might be able to tow a trailer with several of these modules between rock climbing sites, and have the generator on the trailer as well so it can be charging the spent packs while you are doing the climb.

As for the motor, maybe one of these would do the job for you, and at $525 for 19 HP it's not a huge investment, and at 36 lb it's easy to handle. You could even use two of them:
http://www.electricmotorsport.com/store/ems_ev_parts_motors_me0709.php

The controllers are also reasonably priced at $500-$1000:
http://www.electricmotorsport.com/store/ems_ev_parts_controllers.php

But I don't have experience with these. I'm just going on the specs provided. The only less expensive option for DC motors is a fork-lift motor which you may be able to buy for the scrap value, and recondition it. But I really don't advise a series-wound motor, and I personally prefer 3-phase induction types.

If you start by converting a lawn tractor or golf cart to a small rock crawler you can gain much experience at little cost. Otherwise, I suggest you provide a complete set of specifications for exactly what you want, and let an expert design it for you.


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## onegreenev (May 18, 2012)

He's building a ROCK CRAWLER. Because high RPM is not required for the Crawling part a good 11" fork lift motor may be just the thing. Loads of torque and well suited for such heavy duty work at low speeds. Power is required. Good CALB cells are a sure thing and so are the A123 cells. A generator powered with Natural Gas might be in order for those weekend Crawling events. No you don't' need a huge pack of cells. Your going for grunt and not distance but you need more than enough to finish your Crawl. Be sure your charger can handle the output of the generator before you venture into that arena. 

Don't bother with Lead Acid. They just suck. By the way the comparison is good and real. Those 105 AH batteries are not exactly that. And the discharge curve just plain sucks too. The curve is linear and it drops fast as you drive and in no time you have lost the edge of the battery power and your going to be an unhappy camper. With lithium you have power throughout the discharge curve. If you can swing A123 cells you might really consider them. There are a few issues cropping up but not a deal killer by any means and they can provide the amperage punch when you need it with no damage to the cells. 

Pete


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## JRP3 (Mar 7, 2008)

Remember that since top speed is probably very low you can do a lot with gearing instead of a high torque motor, and save some weight and money.


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## onegreenev (May 18, 2012)

Well yes but how many full heavy duty fork lifts have small motors, many do have big motors for a reason. You can with gearing with a forklift too but many have at least a 9" motor. Some have smaller but they are also lighter duty lifts. I'd say go with gearing and torque of a large motor. That is my opinion but in the end it is your decision. I suggested the fork lift motor for the low cost. Weight will be an asset for the Crawler. You don't want them too light either. It is a balancing act on those rocks so a well balanced and good weight vehicle is important. 

Pete


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## PStechPaul (May 1, 2012)

It may be worthwhile to consider adding some UltraCaps for peak load and fast absorption of regen. Here are six pieces of 2600F at 2.5 volts which is 433F at 15V, and the cost is $230. The energy storage is 48700 W-Sec, which is enough for a burst of 8kW for 6 seconds. But that is the total capacity. In reality you would only be able to drain to about 1/2 voltage, to get 3/4 of the capacity. But, still, you can get 6 kW for 6 seconds, or 36 kW for 1 second. These capacitors can provide up to 600 amps and cycle life is 500,000 cycles. 
http://www.ebay.com/itm/6-X-Maxwell...699?pt=LH_DefaultDomain_0&hash=item3f16203743

Just as a point of comparison, we can see what it would take to get 5 HP for 1/2 hour for a high efficiency commuter EV. That is 1.875 kW-H. The capacitor bank above has 13 W-H. So you would need 144 of these banks, for a cost of about $33,000. But at 500,000 cycles, the cost is about $0.07/cycle. 

At 525 grams per cell, 144 banks would weigh 454 kG or about 1000 pounds.

If Moore's law holds true, we might expect a ten-fold improvement of cost and performance in 3 years. So perhaps capacitor technology may prove to be the "winner" in EV technology. Or perhaps, at least, a major part of the solution, maybe even built into batteries, with some "smart" electronics, to improve performance. But this is beyond the scope of this thread.


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## JRP3 (Mar 7, 2008)

Moore's Law applies to the density of transistors on a chip, it has no relation to anything else, such as caps or batteries. I also would not recommend trying to integrate a cap bank for someone new to EV's. Since these caps have a max 600 amp rating then you won't get 36kw from them.


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## Dustin_mud (May 22, 2012)

I'm excited to see how much interest is in my project, thank you for all the info and keep it coming!


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## gte718p (Jul 30, 2009)

There is a lot of potential in an electric crawler. I know a little about crawlers. Mine is below climbing Tank Trap at Hollister. On thing you didn't mention is you intended type of crawling. Comp crawling is very different from rec crawling. Hollister and Moon rocks are very different beasts then trying to run Fordyce or the Rubicon. Johnson Valley is a beast of its own nature. A little more info and I will make my recommendation on parts. I'm just one voice, take it or leave it. There is a lot of experience on this board. I've also built four electric vehicles, two solar cars and two street vehicles. 










What people have been telling you so far is correct. Don't even think about this project with PB acid. Don't go cheap on components. Rock crawling as a hobby is expensive. 

Electric also give you some interesting options. Look at RC rock crawlers. There is no reason the batter pack can not be on top of the axles. It would take a little design work, but would yield great results offroad.

Unfortunately I'm three years or more out from building it, but on of my plans is to build a full scale Losi Venom Crawler as a competition rig. I think it would be about unstoppable.


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## ruckus (Apr 15, 2009)

Pshshst.. Houston, we have lift-off..


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## Dustin_mud (May 22, 2012)

I don't do comps, maybe a local event but nothing pro. As far as trails I Tay pretty local which is Tx so places like k-rocks which is a very technical place, sometimes head out to Nm or Co. No places like Jv where you have a 20 mile drive to the trail head.

Btw nice yota


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## Dustin_mud (May 22, 2012)

Any thoughts on soler power, was thinking just for kicks build the roof on the cage and built into the hood but what could I do with that power? Steering pump maybe? Lol


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## PStechPaul (May 1, 2012)

Well, you can get about 30 watts/sq ft, so a 10'x10' array might give you 3 kW (4 HP). But you might do better with a 10'x10' tarp as a sail. A lot cheaper, and not nearly as fragile. I bought some raw solar cells on eBay for about $1 each for 6 watt 3"x6" and they are supposed to give 6 watts - if they work. Half of them are duds. And they are unbelievably fragile. About like potato chips!


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## JRP3 (Mar 7, 2008)

If you are at all concerned with costs don't bother with solar panels.


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## Dustin_mud (May 22, 2012)

Well you guys got rid of my budget long time ago, just brain storming really


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## ruckus (Apr 15, 2009)

I think a small solar panel is nice on any electric car because it allows people to "see" the energy cycle. Realistically, though, a small panel will not put out enough power to do much in terms of range or recharging.

That being said, the Jaguar is normally charged completely from solar panels.


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## Dustin_mud (May 22, 2012)

I'll messer the area that would be soler later


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## Dustin_mud (May 22, 2012)

Looking at 47x57 on top of the cage and 40x36 for a cargo cover I want to build plus whatever I can mold into the hood.

This is the range extender I was thinking. Lol
http://powerequipment.honda.com/generators/models/eu2000i


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## JRP3 (Mar 7, 2008)

Assuming you might be pulling around 400 watt hours per mile average while climbing and such, a 120V 15A outlet, assuming a usable 12amps, means that generator can put out about 1440 watts, which means with charging losses you might be able to recharge at about 3 miles per hour.


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## PStechPaul (May 1, 2012)

Dustin_mud said:


> Looking at 47x57 on top of the cage and 40x36 for a cargo cover I want to build plus whatever I can mold into the hood.
> 
> This is the range extender I was thinking. Lol
> http://powerequipment.honda.com/generators/models/eu2000i


Hmmm. 9.6 hrs at 2000 watts on a gallon of gas is 18 kW-hr/gallon. The actual energy content of gasoline is about 36 kW-hr/gallon. So that's 50% efficiency, which is pretty good! But it's probably tested and specified at about 50%-70% capacity, or 25%-33% efficiency.

It may be possible to add solar cells to get enough energy to charge the vehicle batteries during extended periods on non-use if there is sufficient insolation. You can get raw solar cells in kit form and do your own tabbing, and they could be glued to the surfaces of a vehicle, perhaps with foam tape. Then you could cover the whole thing with a clear plastic sealer for protection. You have about 27 square feet and maybe as much as 40 square feet if you include the hood. At 10 watts/sqft you might get 400 watts maximum. If you have 8 hours of good sunlight you might get about 3 kW-hr. DIY solar cells might cost you $1/watt so this would cost you about $400, about 1/3 the cost of the generator, but 1/5 the capacity. 

Here is a kit of 200 pieces of 3x6 1.8 watt cells for $161.
http://www.ebay.com/itm/200-3x6-Unt...469?pt=LH_DefaultDomain_0&hash=item1c15fcc58d

You will also need the sealer:
http://www.ebay.com/itm/4-SOLAR-TIT...570?pt=LH_DefaultDomain_0&hash=item35bca47a8a

And the generator will also cost you about $4/18 or $0.22/kW-h, not including the purchase price or maintenance. You can get a 900 watt generator from Harbor Freight for less than $100, but I have one and it's not very good. It's two-cycle and it's noisy.


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## Dustin_mud (May 22, 2012)

Out here in Texas it's nothing but sun when your out on the trails, might be shocked but we have ran trails that have taken all day to run a mile. Lol


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Looking at 47x57 on top of the cage and 40x36 for a cargo cover I want to build plus whatever I can mold into the hood.
> 
> This is the range extender I was thinking. Lol
> http://powerequipment.honda.com/generators/models/eu2000i


Exactly! I was in a campground last year and was walking past an RV. I passed within about 10 feet and then sensed a very subtle whirring/thumping sound. "Is that ON?" I thought. I actually had to walk over and put my hand on it to be sure that it was actually running.

VERY quiet. Only thing to do is adapt a larger fuel tank..

Also, if you are only going a mile or two and hanging out most of the day then solar panels could be of value.


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## Dustin_mud (May 22, 2012)

Guys went out to trees ranch this weekend and this happend. Lucky everyone was ok but that's what happens when you try and bump it. Lol

http://www.youtube.com/watch?v=-sIAfk2M3gE&feature=youtube_gdata_player


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## Woodsmith (Jun 5, 2008)

ruckus said:


> Please remember that series DC motor will have NO braking on downhills. Are you ok with that? Happy to use JUST brakes? Ok, then consider series DC motors.


Just to add to this fact...

My tractor uses a much oversized 9" DC series motor with a Curtis 1214 48v controller. The controller has plug braking which you really don't want on the road but for my tractor, and maybe a rock crawler, it is quite neat.

Plug braking is when current is sent to the motor in such a way that it tries to stop the motor from turning when the accelerator is returned to zero. It is common in controllers for some forklifts and mainly pedestrian controlled vehicles.
It is less efficient as it uses power to achieve that when you would otherwise be 'off the power'.

On my tractor that means that I can drive up a set of steps and I can drive down a set of steps and in either direction I can take my foot off the accelerator, without braking, when the wheels are part way up a step and it will just stop there for a moment and very slowly lower itself back down a step. Left on its own on a ramp it doesn't roll away unless I power off. I have been caught out a few times trying, and failing, to push park it when the contactor switch was still on.
My gear ratios between motor to wheel is about 70:1, 44:1 and 25:1 in 1st, 2nd and 3rd respectively and I run 31" tyres.

The plug braking is so strong that I hardly use the foot brake as, at less then 10mph top speed, lifting my right foot results in instant slowing to a stop.


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## Dustin_mud (May 22, 2012)

And that's something you can just turn on and off from the drivers seat?


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## Woodsmith (Jun 5, 2008)

Dustin_mud said:


> And that's something you can just turn on and off from the drivers seat?


I think so. It is just one additional big cable from the controller to the motor.

If I were to use it on a road car I would just omit the cable so I guess it could just have a big contactor in line.

Currently I only have to switch the reversing contactors off and the motor freewheels so I can push the tractor with one hand while in gear.

I have just (yesterday) blown a diff though so I can't demonstrate for you.


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## PStechPaul (May 1, 2012)

Dustin_mud said:


> Guys went out to trees ranch this weekend and this happend. Lucky everyone was ok but that's what happens when you try and bump it. Lol
> 
> http://www.youtube.com/watch?v=-sIAfk2M3gE&feature=youtube_gdata_player


Yes, it seemed to be a combination of the bounce in the suspension and tires, and the position of the vehicle and a fairly high center of gravity. He was also probably going too fast, and that last turn put him in a bad position. Fortunately the ROPS saved him from a nasty headache! And amazingly the machine landed right side up. 

This also points out that whatever system you use, everything needs to be fastened down securely and be able to survive being upside-down. The driver should probably have a three-point harness and maybe even wear a helmet, especially if the ROPS is just a steel frame. At least that one had a solid roof.

That would have been hell on solar panels, however!


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## Dustin_mud (May 22, 2012)

Oh I been in this sport for about 7 years now and owned many rigs, one of the first things you do is build a solid cage that goes straight to the frame and harnesses are a must.


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Guys went out to trees ranch this weekend and this happend. Lucky everyone was ok but that's what happens when you try and bump it. Lol
> 
> http://www.youtube.com/watch?v=-sIAfk2M3gE&feature=youtube_gdata_player


This type of thing makes me concerned for these and all the other folks running without doors. Those sharp rocks or a stump can reach out and get you in a situation like that. I'd like to see more half-doors or bar-doors on these rigs.


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## Dustin_mud (May 22, 2012)

Lots of people run half doors and door bars, luckily rolls like this don't happen often. Most of the time there simple low speed flops, this was a " hold my beer and watch this". Lol


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## gte718p (Jul 30, 2009)

If I had my choice. I would go with a solitron 1 controller and a warp 11". Motor and controller will run you around 6 grand. 

I have never personally used the solitron. However, I have never read anyone dislike the controller. The high current is necessary for a good crawler. Some times you just need wheel speed. The 11" motor will provide all the torque you could possibly need. Especially when paired with a well geared transfer case.

Batteries 38 x 200ah LIPO4
Thats another 8-9 grand.

I'm not a fan of salvaged motors or controller for this application. Being out on the trail is not a good place for equipment to let you down. Its not like being on the road were you can call a wreckers easily. I've had to rebuild engines and transmissions in the middle of no where just to get home. Its not fun. One of the benefits of an electric crawler is there are quite a few less moving parts and less things to break. However, when they break many of the items are not repairable. If you lose a pole in the motor or the motor or controller shorts there is not a lot you can do other then replace the entire thing. I've had both happen in the solar racing world.


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## JRP3 (Mar 7, 2008)

It doesn't seem as if these crawlers are high HP machines, the 1000amp 300+ volt capability of the Soliton1 would seem wasted. I think the Soliton Jr with 500 amp continuous and 600 amp peak with a 9 inch motor would be better, and cost a lot less, and you can use more slightly smaller cells to get higher voltage. This seems as if it would make more sense with the low gearing and low top speeds needed for crawling.


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## gte718p (Jul 30, 2009)

I'll admit its probably over kill and you could get away with less.

I like the larger motor for its higher stall torque. Crawling spend a lot of time at stall. Larger motors are also large heat sinks so they take longer to over heat at stall. Of course the down side is they also take forever to cool down once the are hot. 

HP is always your friend. More HP gives you options. Its not an absolute requirement, but its not uncommon to see big 350s and larger engines. Wheel speed can be a powerful tool. You also don't know what you will run into. Its not uncommon to run into patches of mud or snow. There is no replacement for HP in mud or snow. You also need speed and power to jump obstacles some times. The picture of my rig taking off is a perfect example. Its a 14 ft near vertical climb. Its a loose surface so its hard to crawl over. You use tire speed and claw your way up. 

Personally I also like to be able to get a little speed going between obstacles. Crawlers are geared so low, it takes power to get any speed up. My toyota is redlined and screaming to get up to 40 mph. The larger controller allows you more room.


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## Dustin_mud (May 22, 2012)

Where we wheel there's very little mud, and if at all possible I'll drive around it. I myself are not a fan of hi hp crawlers that just =s broke parts and lots of time on the roof


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## Dustin_mud (May 22, 2012)

Found a pretty cool lexan hood that's clear for my jeep, so that will shave fat and now I can build a soler panel the size of the hood. Just make it cover the hole engine area and the hood will protect it.


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## Woodsmith (Jun 5, 2008)

The low power with a high ratio and a very low ratio in the trans sounds like the simplest option.
I know my tractor is only limited by tyre adhesion and transmission strength. It will more then happily crawl at less then 1mph and burn rubber at 10mph. I need a higher gear for getting about.

When I rebuild it will be with a view to sub 1mph crawl and 20mph top speed.


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## Dustin_mud (May 22, 2012)

Been looking at a trans warp9 into a tcase that has a 1to1 high and a 6.5to1 low. Would that work out ok?


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## Woodsmith (Jun 5, 2008)

That makes a nice range of ratios!

I wouldn't mind one of those myself.

I reckon it is a good starting point to calculate from.


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## JRP3 (Mar 7, 2008)

The thing is having a transmission allows you to fine tune your gearing as needed, plus you don't have to mess with reversing contactors. I think I'd try to use a transmission.


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## Dustin_mud (May 22, 2012)

Looking to save weight..


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## ruckus (Apr 15, 2009)

Woodsmith said:


> Just to add to this fact...
> 
> My tractor uses a much oversized 9" DC series motor with a Curtis 1214 48v controller. The controller has plug braking which you really don't want on the road but for my tractor, and maybe a rock crawler, it is quite neat.
> 
> ...


This is very interesting. They call this "hydrostatic" in hydraulics. This is a MUST HAVE for a crawler (or for any high-slope vehicle). You want to be able to maintain your position on the hill.

Thanks for this heads up..


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## DanGT86 (Jan 1, 2011)

I really hope you end up building this. I have always thought a rock crawler would be a perfect EV. 

I can tell you that my EV econo car has more low speed control than my 22re toyota pickup in low range. When crawling it up onto ramps I can litterally comand 1 wheel turn at a time.

You could use dual toyota transfer cases. Stack a 2.88 and a 4.7 transfer case and you might not even need a transmission. Use direct drive for getting from one obsticle to another and crawl in the t-case ratios. 

I think some type of electronic engine braking is a must. Using the regular brakes seems like it would be harder to control. 

Cool thing about the EV is that there is no idle or engine reving needed. You just request the amount of wheel turn you need and it comes out of the battery pack. No goofy clutch slipping or being out of your powerband. I think that and the lack of high speed aerodynamic losses will give you pretty good range/time on the trail.


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## Dustin_mud (May 22, 2012)

Yeah I can't wait, already getting my suspension and axles together.


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## gte718p (Jul 30, 2009)

If you go Toyota for axles some longfields are definitely in order. Your talking about a lot of near instant torque especially if you go with an 11"
I like the Toyota dual cases. They are hard to beat. You can easily do a built setup with marlen or trail gear parts for half of what an atlas costs. 

I would go with a d60/14 bolt combo. Instead of a truss I would build a battery box on the axle. Unsprung wieght is the enemy of just anout every vehicle, but its great on a crawler. But that's another 2k. Man it serves to remind me that crawling is an expensive habit.


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## Dustin_mud (May 22, 2012)

I already have d60s for the front and rear, waiting on a set of 7:17s for them.


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## JRP3 (Mar 7, 2008)

You don't want to subject your expensive batteries to the same impacts as your axles.


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## Dustin_mud (May 22, 2012)

Little update, slight change in plans. Going to still be a crawler but after spending time on the site I desided to make it street able. Going to down size the tires to a 35 and maybe 5:13 axle gears, oh and also going to get a aluminum body for it to save a lot of weight. Thoughts?


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## DanGT86 (Jan 1, 2011)

That still sounds cool but the budget is probably going to have to grow quite a bit. Off road vehicles are not particularly fuel efficient. The bad aerodynamics, weight, and big high rolling resistance tires are all bad for range. Getting a low power thus cheaper EV to make a lot of torque for crawling is easy because you don't need to do it quickly. It takes power to push a vehicle through the wind at a decent speed. Torque can be made with gears but power seems to always require money. 

Just depends on how far and fast you need it to go on road and how much you want to spend. If the budget only allows for a cool crawler *or* an on road economy build, don't compromise on both trying to combine them and be disappointed with the result. 

I can say that my small toyota 4x4 pickup will only go little over half as far on a gallon of gas as a sedan of equal weight. That difference wouldn't go away just because they both were electric. 

Check out evalbum.com for jeeps and trucks that have been converted to give you an idea of what it would take.


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## Dustin_mud (May 22, 2012)

Yeah budget is out the window now, I really want to be able to hit freeway speeds and a range of about 80 mile....would love more but that maybe not possible


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## Dustin_mud (May 22, 2012)

I know this sounds crazy but its going to light like 2400 pounds.


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## DanGT86 (Jan 1, 2011)

Weight is a factor but at freeway speeds rolling resistance and aerodynamics are the killers. If it were something really small like a samurai and you could change the ride height and tire size drastically depending on type of use then maybe you could trick it into economy car style range. I would think anything crawler like is not going to be very aerodynamic. Not to mention the stronger axles and big diff gears usually put a lot of parasitic drag on the system. Lots of thick oil for giant gears to sling around.

As you figure up your budget you may find that its cheaper to make a cool little single seat EV buggy/crawler and have enough money leftover to make a nice little road going EV. 

If the budget is out the window then this is going to be really cool!


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## JRP3 (Mar 7, 2008)

Now are you going to use a transmission?


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## Dustin_mud (May 22, 2012)

Yes a jeep 5spd, aluminum case


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## JRP3 (Mar 7, 2008)

This is going to be pretty similar to something I've wanted to do for years, definitely interested in your results, and happy to let someone go first


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## Dustin_mud (May 22, 2012)

Do think I'm going with the warp9 and looking into the headway cells, know I would have to run a lot of them(not sure how many yet) but will let me get crazy with hiding them.


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## JRP3 (Mar 7, 2008)

Their quality control can be a bit sketchy from what I've read, be prepaired to buy some extras. Some who have used Headways say they'd probably use CALBS or other prismatics if they did it again. Personally I wouldn't mess with them for a large pack.


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## Dustin_mud (May 22, 2012)

Yeah I was reading a thread on them, but just for shits and giggles how many would be a good number to run? At only 8ah it's going to be a lot. Lol


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## JRP3 (Mar 7, 2008)

Let's say your vehicle will average 400 watt hour per mile. A 40 mile range means 16,000 watt hours or 16 kilowatt hours. Each cell is 3.3V x 8ah = 26.4 watt hours. 16,000 wh / 26.4 wh = 606 cells. Voltage sag would actually reduce the real watt hour rating of the cells so you'd need even more.


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## Dustin_mud (May 22, 2012)

Wow yeah that's more then I thought. Lol


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## Dustin_mud (May 22, 2012)

JRP3 said:


> Let's say your vehicle will average 400 watt hour per mile. A 40 mile range means 16,000 watt hours or 16 kilowatt hours. Each cell is 3.3V x 8ah = 26.4 watt hours. 16,000 wh / 26.4 wh = 606 cells. Voltage sag would actually reduce the real watt hour rating of the cells so you'd need even more.


Run the 15ah and almost cut that number in hafe, yes?


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## JRP3 (Mar 7, 2008)

Yup, 323, still seems like a pain to mess with.


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## darkstar02 (Jun 8, 2012)

An electric and biodiesel w/HHO hybrid Samurai would be awesome. How about using a turbine hooked up to an alternator that charges supercapacitors when they drop below a certain amount of electricity?


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## DanGT86 (Jan 1, 2011)

darkstar02 said:


> An electric and biodiesel w/HHO hybrid Samurai would be awesome. How about using a turbine hooked up to an alternator that charges supercapacitors when they drop below a certain amount of electricity?


Probably be cheaper just to run a steam engine but shovel dollar bills into the boiler instead of coal. 

Most of those are cool technologies but really expensive for the DIY. Especially all on the same vehicle.


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## JRP3 (Mar 7, 2008)

That post has to be a joke, or the beginning of a spam campaign


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## darkstar02 (Jun 8, 2012)

Is it really that laughable? 

http://green.autoblog.com/2007/10/20/biodiesel-turbine-super-capacitor-series-hybrid-hummer-60/

http://green.autoblog.com/2009/12/04/la-2009-cmt-380-packs-microturbine-li-ion-battery-into-a-matte/

etc

I don't know shit about electric vehicles but I'd mob an electric samurai.


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## JRP3 (Mar 7, 2008)

Since this is a site for DIY *electric cars*, incredibly expensive and complex *hybrids* don't really have much interest for us


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## gte718p (Jul 30, 2009)

darkstar02 said:


> Is it really that laughable?
> 
> http://green.autoblog.com/2007/10/20/biodiesel-turbine-super-capacitor-series-hybrid-hummer-60/
> 
> ...


Meh. For $375000 I'll build you a much cooler car without the turbine.

Also completely inappropriate for this thread. Turbines don't like to be shocked. First time you rolled over your turbine would eat its self. It's spectacular hen it happens, but bad.

If you really insist on a gas turbine for your ride I suggest talking to this guy for inspiration. http://ronpatrickstuff.com/


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## ruckus (Apr 15, 2009)

darkstar02 said:


> An electric and biodiesel w/HHO hybrid Samurai would be awesome. How about using a turbine hooked up to an alternator that charges supercapacitors when they drop below a certain amount of electricity?


How about making the passenger seat an exercise bike w/ alternator? 

Completing an electric crawler is project enough. Once you have that done, then you can add the crazy stuff. Otherwise, it will never be finished.

JMHO


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## Dustin_mud (May 22, 2012)

Don't get on him to bad guys, just giving out ideas. Got to say that's pretty wild but could never fit in a jeep and couldn't aford it anyways. Lol


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## PStechPaul (May 1, 2012)

I just posted a new video of my electric riding mower project, and I found this about a Craftsman tractor rigged up as a crawler (but not electric). You might consider going this route as a start. Or maybe you can get some ideas. It looked pretty cool, but obviously dangerous without a ROPS: http://youtu.be/qRh64bXHY3k


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## Dustin_mud (May 22, 2012)

Sorry about the lack of updating, this and another ev project got put on hold but looking into jumping right back where I left off.


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## Dustin_mud (May 22, 2012)

Ok think I'm getting a good idea on my drivetrain so the next obstical will the the accessories and steering. My idea on this is a electric steering pump that runs on a sealed 12v auto batt that will be recharged from a alternator powered by the motor that way the steering will have no real drain off my range pack. Thoughts on that idea, haven't really had much time to look into that theory.


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## JRP3 (Mar 7, 2008)

Pump > Battery > Alternator > Motor > ________ 
Fill in the blank.


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## Dustin_mud (May 22, 2012)

Battery I'm guessing your going to say but I can't imagine spinning a alternator that much of a drawl, I should clarify the alternator will only spen when the vehicle is moving.No idling and only putting a charge to the 12v which is what an automotive alternator was designed to do.


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## JRP3 (Mar 7, 2008)

The draw will be whatever power the steering pump requires, plus all the conversion losses along the way from battery pack to controller to motor to alternator 12V battery to the pump. Your proposed setup is very inefficient. A better and more efficient system would be an electric power steering pump running at pack voltage. Is there even an electric steering pump that runs off 12V? Seems as if current draw would be pretty high, though probably for short duration.


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## Dustin_mud (May 22, 2012)

I have to see what the draw on it is but a good friends buggy uses a electric pump for his rear steering and that's just off a normal 12v system.

Why would I need to run the power to the controller at all for the pump, couldn't it be it's own closed loop? Just run it on a switch or would that be the same as going to the controller?


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## JRP3 (Mar 7, 2008)

The way you described it you want to power the pump from a 12V battery, which is charged by the alternator, which is turned by your drive motor, which is controlled by the motor controller, which gets it's power from the main pack. Or did you mean a separate motor to spin the alternator? If that is the case, why not just use a separate motor connected to the main pack that spins a conventional power steering pump, and skip the 12V battery and alternator?


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## Dustin_mud (May 22, 2012)

I ment of the main motor, it's hard for me to explain I guess( not very good with spelling/typing). The pump will be wired straight to the 12v batt so that when I have to stop forwarded momentum I still have steering, but the alternator will be on a bracket on the front of the motor and will spin when the motor spins. 99% of the time the alternator will be keeping a charge on the 12v but for 30 sec to a min when I stop to line up the pump will work just off the 12v. Make sense?


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## JRP3 (Mar 7, 2008)

Yes, that's what I originally thought you meant, which means the power flow from the pack will be main battery pack > controller > motor > alternator > 12Vbattery > pump. That's a pretty convoluted path with efficiency losses at each step. However depending on how often the pump needs to actually run and how much power it's actually drawing it may not be that much total energy lost. 

If the pump current draw is low enough you may be able to run it from the DC/DC converter, so the power flow would be main battery pack > DC/DC converter > 12V battery > pump. That takes the main motor and controller out of the power supply chain for the 12V system and replaces the alternator with the DC/DC converter. You could potentially skip the 12V battery too but I think it's good to have it in place for a buffer for short term heavy currents the DC/DC may not be capable of delivering.


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## Dustin_mud (May 22, 2012)

I see what you mean, I'll have to get specs on the pump.


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## Dustin_mud (May 22, 2012)

Also a few pages back we discussed solar panels, maybe that would be a good way to keep a charge going to the 12v?


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## JRP3 (Mar 7, 2008)

Not enough output to keep up with your use. Plus expensive.


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## Dustin_mud (May 22, 2012)

New full tube chassis will be delivered on the first, will post some pics.


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## Dustin_mud (May 22, 2012)

Got the chassis in today, looks like a damn good start. 

Now Im worried about water geting to the motor and pack, cant get any real good info on whats going ot happen if the go under water.


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## onegreenev (May 18, 2012)

I would not worry too much about getting the motor wet. Worry more about rocks getting inside. As long as the motor can drain it should be fine. As for the batteries? Do you really plan on sinking them so deep that they cover the tops of the cells? Nothing will happen but water can get between the connections and corrode over time. If the pack is never burried in water above the tops and has good drainage then you should have no troubles. If on the other hand you do sink the cells that deep then you might need to come up with a fool proof water proof box. You won't electrocute yourself if that is your worry. Old time torpedoes were electric motor driven with a one time use battery and the motor compartment was flooded and the battery sealed. Motors run underwater.


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## Dustin_mud (May 22, 2012)

Ok thank you, yes it was a safety and concern of the life of my parts.


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## onegreenev (May 18, 2012)

Still best to keep things as dry as possible.


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## JRP3 (Mar 7, 2008)

onegreenev said:


> I would not worry too much about getting the motor wet.


I doubt running a motor in water would be a good idea. The internal fan could break and you might get arcing on the commutator. I'd suggest a sealed liquid cooled AC motor if you plan on stream crossings and such. Or build a baffled enclosure for the motor that allows cooling air but no water to enter if you are using a series DC motor.


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## Dustin_mud (May 22, 2012)

Heres the start


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## onegreenev (May 18, 2012)

JRP3 said:


> I doubt running a motor in water would be a good idea. The internal fan could break and you might get arcing on the commutator. I'd suggest a sealed liquid cooled AC motor if you plan on stream crossings and such. Or build a baffled enclosure for the motor that allows cooling air but no water to enter if you are using a series DC motor.




As I mentioned before. Keeping things dry is best. Getting the motor wet is one thing, playing submersible is quite another. I would not worry if it gets wet but running under water is not the most ideal. Motors can run fully submersed. I did not think about the fan issue. My motors don't have them. Getting splashed with water and able to drain, I still would not worry to much.


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## Dustin_mud (May 22, 2012)

Oh recommendation on a sealed AC that won't break the bank?


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## JRP3 (Mar 7, 2008)

About the only choice at this point is the Siemens from the Azure Dynamics bankruptcy. Some people on the forum were selling them, but if they are all gone you have to go to Jack Rickard at EVTV to get one. A control interface is still being developed for them but progress seems to be good.


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## JRP3 (Mar 7, 2008)

onegreenev said:


> Motors can run fully submersed.


You've seen a submerged series DC motor running?


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## Dustin_mud (May 22, 2012)

Looking into a deal with the ac24ls, how does that compare to the dc warp9? Say I use this controller:HPEVS Curtis 1239-8501 144V 500 AMP Controller


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## JRP3 (Mar 7, 2008)

Probably one of the worst AC motors, and not liquid cooled.


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## Dustin_mud (May 22, 2012)

Good to know, sorry for all the questions. Thought I had a handle on most of this but really starting to see I don't know S, not feeling to good about my lack of knowledge.


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Got the chassis in today, looks like a damn good start.
> 
> Now Im worried about water geting to the motor and pack, cant get any real good info on whats going ot happen if the go under water.


Running under water should be no problem with components rated to IP65. The Scott Drive is IP65. The Siemens motor is IP65. The BLDC motor is IP65 except for the connector (IP54) which can be switched to the Siemens connector. 

For crawling I would much prefer the BLDC because it has about double the torque of the Siemens. Both are good motors, they just have different applications depending on if you want stump-pulling grunt or crazy rpms.

Cheers


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## JRP3 (Mar 7, 2008)

Dustin_mud said:


> Good to know, sorry for all the questions. Thought I had a handle on most of this but really starting to see I don't know S, not feeling to good about my lack of knowledge.


That's where we all started


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## Dustin_mud (May 22, 2012)

BLDC: Guessing a brushless DC motor? Who makes these motors and what kind of prices? I feel like I'm getting priced out on AC, witch really sucks the more I think about it( regen braking would be very nice).


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## Dustin_mud (May 22, 2012)

JRP3 said:


> That's where we all started


I understand that, just feel pretty damn stupid having to ask what seems like simple questions. Sure it gets annoying...lol


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> BLDC: Guessing a brushless DC motor? Who makes these motors and what kind of prices? I feel like I'm getting priced out on AC, witch really sucks the more I think about it( regen braking would be very nice).


How much torque do you want? 

Are you using a transmission or just a transfer case?

I would expect regen to be critical in a crawler application where it would be very nice to "cling" to a difficult spot while deciding what to do next. Let off the go pedal and the vehicle would freeze in place without having to apply the brakes.


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## Dustin_mud (May 22, 2012)

Without trans around 120tq+ 
With trans 80+


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## Dustin_mud (May 22, 2012)

I can go for a lot more just looking at what the ice is puting out.


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## Dustin_mud (May 22, 2012)

I love the numbers of the Siemens but I from what I read is at one time the market was overrun with them and prices were cheap but now all I can find is evtv and I can't swing what they are asking right now. Also the Scott Drive, what does that run? I looked but found no price on one.


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## onegreenev (May 18, 2012)

Im putting my money on the HPEVS AC system. Kind of hard to beat unless you NEED those high voltage motors. I can say that the Siemens you find at EVTV are actually well priced. They are however orphan systems and when that supply runs out there is nothing. The only one that is really a player in this market today is what HPEVS offers.


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## JRP3 (Mar 7, 2008)

Another way to go would be to find a wrecked EV, like a LEAF. You might get everything you need at a very reasonable price. The HPEVS motors are air cooled but the 7X series are non vented, so I suppose they could be water proof, you might check with HPEVS about that. The 3X siamese motors might also be sealed.

http://hpevs.com/the-drive-systems.htm


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## ruckus (Apr 15, 2009)

The HPEVS AC45 can be found for about $1500 on Ebay. With controller and chill plate it will run you about $3600. Cheapest AC option, not submersible and fairly low on grunt (130 ft lbs), but adequate and has regen (not sure how adjustable).

One of the smaller BLDC motors (35 kW) and a Scott Drive 100 would run around $5500 (plus shipping), so a bit more expensive. However, it would be submersible and even the smallest BLDC still puts out more than 200 lb ft. The regen is adjustable and can provide full motor torque as braking.

The difference in voltage is not a big deal. You will run fewer large batts or more smaller batts. The cost for the pack is based on overall size (kWh), not voltage. The Scott Drive can be run from 200-400V so it has a bit more flexibility in terms of using a "starter" pack and adding more juice later.

If cost is more important than power, I would look at the HPEVS systems.

Cheers


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## Dustin_mud (May 22, 2012)

Ok I didn't know you can run regen on a BLDC, learn something new everyday. You have a link where I can look at prices and specs of some BLDC?

As for battery pack I been reading the thread about the chevy volt pack and really like the idea of getting a 16kwh pack for 2k, I understand I would have to brake it down into smaller packs but seems like a good deal.


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## JRP3 (Mar 7, 2008)

I thought the $2K price was for only a module, not the whole Volt pack?


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## Dustin_mud (May 22, 2012)

From what I read its for the hole pack, also did a parts search and found a few.


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## ruckus (Apr 15, 2009)

Dustin_mud said:


> Ok I didn't know you can run regen on a BLDC, learn something new everyday. You have a link where I can look at prices and specs of some BLDC?
> 
> As for battery pack I been reading the thread about the chevy volt pack and really like the idea of getting a 16kwh pack for 2k, I understand I would have to brake it down into smaller packs but seems like a good deal.


Chevy volt runs the Remy. Good example of a PMAC/BLDC.

http://www.remyinc.com/docs/HVH250R4.pdf

Sounds like you are looking for a rolled Volt.


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## Dustin_mud (May 22, 2012)

Really looking for a winnig lotto ticket so I can pay for all this. lol


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## Jeremyfc1 (Feb 5, 2016)

Look up electric samurai on YouTube. That is my sami. I am currently in the parts gathering stage for a ac drive 450ftlb crawler using a Toyota driverrain


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## gte718p (Jul 30, 2009)

Holy thread necromancer. It is back from the dead.

Funny though I was just wondering what became of this project and the guy wanting to build one for Google.


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