Diesel to Electric Mini-Digger Conversion - Feasability Study

[jackpreacher]

This may be impractical but is there any reason why my Volvo EC15B 3cylinder diesel mini digger can't be converted to run on a DC electric motor?

In simplistic terms the hydraulic motor requires rotational energy to be applied to it's driveshaft by a reliable motor of sufficient power/torque.

The diesel motor is rated around 15HP which is possibly the equivalent of an 8HP LX motor ( LX - electric). The RPM can be governed by the voltage of the battery pack so no need for a £1000 controller, just eight 12V batteries, and lead acid at that as the weight would be an advantage. A 48V line voltage would be ideal.

Plus, once installed on a sliding tray like the Mitsubishi L3E motor is now, it would be easy to slide out and put the diesel back in for various reasons like.......it not working, or sliding in a spare battery pack.
I could sell the L3E for, I dunno......£1000 which would fund a lot of the conversion.

Ok chaps.......knock it dead.....I'm ready

[Muz]

This may be impractical but is there any reason why my Volvo EC15B 3cylinder diesel mini digger can't be converted to run on a DC electric motor?

In simplistic terms the hydraulic motor requires rotational energy to be applied to it's driveshaft by a reliable motor of sufficient power/torque.

The diesel motor is rated around 15HP which is possibly the equivalent of an 8HP LX motor ( LX - electric). The RPM can be governed by the voltage of the battery pack so no need for a £1000 controller, just eight 12V batteries, and lead acid at that as the weight would be an advantage. A 48V line voltage would be ideal.

Plus, once installed on a sliding tray like the Mitsubishi L3E motor is now, it would be easy to slide out and put the diesel back in for various reasons like.......it not working, or sliding in a spare battery pack.
I could sell the L3E for, I dunno......£1000 which would fund a lot of the conversion.

Ok chaps.......knock it dead.....I'm ready

I dont want to burst your bubble ... but In a second you will be listening to Michael Bubble, and forget you have a cable .. run over it and damn your new invention

Dont get me wrong they do exist where zero emissions are mandatory

[jackpreacher]

I dont want to burst your bubble ... but In a second you will be listening to Michael Bubble, and forget you have a cable .. run over it and damn your new invention

An excellent singer

No cable though. It won't be a 3-phase plug in type, more hefty battery pack and keeping an eye on the gauges

The Maths:

48V battery pack running at maximum 8000Watts runs at approx. 160-200 Amps

To operate at full power for an hour requires a battery pack of 250 Amp.hrs with an efficiency of 80%.

So four 110 Amp.hour batteries with a maximum 50% discharge gives a comfortable 60mins work with full power and idle time.
Eight batteries will give between 2 to 2.5 hours. That's enough for me, but not for the professional operators.

[jackpreacher]

http://ceca.roplnews.com/welcome/ind...ini-excavator/

[Muz]

The Maths:

48V battery pack running at maximum 8000Watts runs at approx. 160-200 Amps

To operate at full power for an hour requires a battery pack of 250 Amp.hrs with an efficiency of 80%.

So four 110 Amp.hour batteries with a maximum 50% discharge gives a comfortable 60mins work with full power and idle time.
Eight batteries will give between 2 to 2.5 hours. That's enough for me, but not for the professional operators.

Hmm .. but your machine will have its motor loaded hugely most of the time .. I think thats why diesels are favoured

[jackpreacher]

Hmm .. but your machine will have its motor loaded hugely most of the time .. I think thats why diesels are favoured

Yes, I've read in some of your other posts that you run basically at full revs most of the time, and hence, full power/torque when calling on services, so it's the torquiness of the diesel that's important or we'd have petrol engined diggers
LX motors generate full torque from standstill - that makes them a perfect match for hydraulics.

[jackpreacher]

Pros and Cons of LX versus Diesel

Pros

1. No fumes - Diesel fumes are terrible for your health.
2. Much cheaper to fuel up, especially on off-peak electricity tariffs. Could be free if solar panels are used.
3. Quieter
4. No oil, air or fuel filters to maintain - cheaper, easier maintenance
5. Can work indoors

Cos

1. No straightforward cab heating
2. Long recharge versus diesel filling time
3. Limited operational endurance
4. Weatherproofing could be an issue.
5. Batteries need TLC or they'll die quickly, andd they're expensive, as are solar panels.



..anything I've missed?

[245dlc]

Takeuchi recently announced a battery powered mini-excavator, you don't get much of a run time but I guess it can be done. And I've seen on youtube somebody who must of converted themself a JCB micro digger to electric that runs of some kind of extension cord, many mining shovels these days run off of an umbilical cord that runs something like 7200 volts through it.

http://www.youtube.com/watch?v=fSLCokezKvg

http://www.youtube.com/user/CreteBusters?feature=watch

http://www.youtube.com/watch?v=LMOFH5oqsaM

[jackpreacher]

Takeuchi recently announced a battery powered mini-excavator, you don't get much of a run time but I guess it can be

That'll be expensive with all those Lithium batteries. Do electric forklift trucks use hydraulics for their lifting gear or direct drive electric motors?

[245dlc]

The one's I have run in the past when I use to work to do warehouse work in the winter all had hydraulics for lifting but those I think were lead acid batteries which also acted as counterweight.

http://www.crown.com/usa/products/pd...file_sheet.pdf

[jackpreacher]

So those were with twin electric motors, one for traction and the other for the hydraulic power pack?

I found this on EBay:

http://www.ebay.co.uk/itm/Lansing-Ba...#ht_500wt_1054

It seems ready to plumb in, virtually.?

[Gridley]

I know it`s an old thread but I`ve just noticed it.
Got electric forklifts here,three of them.A new battery pack is now over £4000 and they need an eight hour charge every eight hours if you use them eight hours.I factories where they are used all the time you have extra battery packs so one is in the machine,the other is on charge.The Lansings used to come with a little jib which fitted on the end of the carriage to lift the batteries off and on.
Also got a cherrypicker but it only has four six volt deep cycle batteries on it at £96 each.
I think you can get diggers for static factory use (not for digging ) which are mains powered.Sure I`ve seen something somewhere.Mebbe in my sleep. :D
How were you going to charge your digger?

[jackpreacher]

How were you going to charge your digger?

Oddly enough I was thinking about this today as I was removing the diesel engine out for a full inspection! We have a micro-hydro generation project ongoing which will generate 10kWhrs 24/7. So, 8 hours to charge for free. It may not happen though as the digger may not be worth converting for the hours I will use it.

Ex-forklift batteries are great for backup power - what do they do with the old ones?

[Gridley]

Old batteries go to the scrap man.Don`t know the current price but probably about £450 - 500 tonne.
Would cost more than that to buy them back of him but battery failure is the most common reason for electric trucks being scrapped so debatable if they are worth buying back.
Probably better to buy a forklift at a sale to strip that way you would get the charger.
Other problem might be matching the battery output to what your motors need to get sufficient pump flow.Forklift pumps won`t give you the speed of movement the original machine pump would.
I don`t think there would be long term financial savings in such a project but that`s just me and I`ve got a feeling you do things for the sake of doing them and won`t be too peed off it it`s not a total success.
A sign of too much time on your hands,perhaps? :D
How do I turn on smileys in this forum?

[jackpreacher]

A sign of too much time on your hands,perhaps?

I wish


I'm inclined to agree with you that it isn't financially worth it. It was an idea hatched when my EC15B smoked out the garages every time I started him up.........got fed up of venting with fans.