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Thread: Electric Coach Conversions - Thoughts?

  1. #11
    Join Date
    May 2012
    Beverly Hills


    Clearwater, great references.

    For urban truck travel it looks like battery power is here now in some parts of the world. 3,000 pounds of batteries for a 150 mile range looks like a limiter to long haul least for now. The equivalent of 50 Tesla battery packs for urban applications must also pose a space and cost concern.

    You're not far off with a Detroit series 60 and transmission being in the $40K+ range. In fairness, the long term cost must also be factored. Electric motors win on long term service costs, although I wonder what their life expectancy is. The cost per mile over the life of the batteries would be interesting. Your references had a comparison chart, but it wasn't clear if that was just fuel versus charging costs or it included the cost of the batteries. All just numbers, but numbers limit customer acceptance.

    Thanks for sharing.

    Gil and Durlene
    2003 H-3 Hoffman Conversion

  2. #12


    Of course Gil, Sharing is what forums are all about

    I was thinking about the weight's of all this stuff as, at the end of the day, what you need to push you down the road (and stop you moving) is directly proportional to that number.

    Most Prevost's seem to have 250 gallon diesel tanks right? A gallon of diesel weighs 6.943lbs (lets round that up to 7 pounds and ignore the weight of the gas tank it's self for this fuzzy maths calculation). So a tank of go juice weights you down 1750lbs. And that falls over the trip as fuel is burned.

    The engine it's self, a Series 60 is about 2800lbs, and an 8V92 is 3200lbs. So we're looking at an average of 3000 between the two most common power-plants in Prevosts (I'm not counting the D13, but I think it's in the same range).

    With the fuel and engine it's around 4950lbs, lets just say 5000lbs. And then you've got the Allison Trans weight dry/wet... Average it at another 1000lbs on top:
    Or around 6000lbs for a traditional diesel power plant and it's go juice.

    If the battery bank mentioned in the PDF weighs in 3000lbs, This leaves 3000lbs for DC motor weights and gearing. But DC motors don't weight anywhere near that range and are much much much lighter. Just for examples sake, and because so much of this data is readily available; I want to say the dead in the middle of the range single motor P-series 85kWh Model S's drive-train - which includes the single DC motor, electrical converter, control module(s) and the drive-line differential gearing box all together - weighs in at 150lbs. And that really tiny power plant nets you 443 lb⋅ft / 601 N⋅m of torque & 470 hp / 350 kW of HP. I think two of those in series would be better for a bus, or around 880 lb⋅ft / 1200 N⋅m of torque & 940 hp / 700 kW of HP in exchange for 300lbs of weight. That seems pretty decent as a start right?

    Andy Gadget Guru: Thank you for adding in the links and info / ideas you did. I think you might be onto something with the idea that soon "this industry could be undergoing a revolution".

    And on a more personal level - the BIG THING that keeps one of my own (Clearwater) eyes on this topic is the following: I look to this type of conversion as a means to reduce mechanical complexity, reduce running costs and reduce service costs for big rig ownership and operation. THAT, is the big deal for me personally
    Last edited by CLRH2O; 07-11-2018 at 11:31 AM.


    CLRH2O (Clearwater) & SenseNet (Cheney)

  3. #13
    Join Date
    Jun 2013


    Just so we are clear, I totally expect this to be the "norm" of the future. Moving people and freight from point a to point b is a different animal than a motor home conversion. If a person has to pay full retail, the Detroit prices aren't too far off for an RV owner.

    As to the projected costs and reliability, I have my reservations on the electronics involved to control the charging and temperatures of the battery banks. We have already experienced some of this on a much smaller scale. The training of technicians and the price of the equipment the shops will need is mind boggling. I'm glad I'm aging out of the service You think its hard now to find a campground to get reliable 50a service for overnight parking just imagine the infrastructure needed for the future.

    Almost every PLC controller or module ages out from 1-5 years costing a lot of time and money to retro. You may reduce some mechanical complexity, I don't think so, but the added technical complexity will take some time to adapt to for a shop in the Smoky Mountains or The Black Hills. A piston in a Detroit hasn't changed much over the years.

    As a side note, most folks who know me, know that I really love

  4. #14


    All very valid points Donny.

    I'm interested in hearing more about your experiences with the PLC / module(s) aging out and retrofitting thus far. There's bound to be a lot worth hearing there.

    Battery temps are real concern, just as much as engine coolant temps are, that is for sure! You end up with a hefty engine rebuild bill when you get too hot right now. In the near future you melt part of a compartmentalized battery bank down and end up with a hefty rebuild bill just the same. Cooling when dealing with energy will always (and should always) be a concern to handle appropriately.

    We can foresee a nice perk with cooling systems for battery banks being that the coolant it's self doesn't age out of service as quickly as SCA type 2-stroke coolant, and even 4-stroke coolant today does. Currently our coolants age out incredibly fast due to breakdown and contamination. I mean, the general methodology is a 'drain and fill' annually which is coo-coo when you really think about it. But the operating environment inside a diesel engine is a harsh place, and this it's the reality of things right now. Overall, battery bank interleaved closed loop systems will inherently operate more-or-less trouble free for longer, and that will be a plus. This doesn't mean without any issues at all - that's folly to think. But just that the coolant it's self not needing to be switched out for the life of the bank is an advantage over the annual drain and fill system we currently work within for the buses right? One less fluid to change has to be a good thing. It's certainly one less thing the owner will invariably forget about and F-up lol

    And don't even get me started on the cheapo "B.attery M.anagement S.ystem" units that flood the low-end and mid-range market. Honestly, if it's not Victron or another well engineered system (there are a number that are worthy) I'm HIGHLY suspect of it's mere existence... let alone the thought of letting one physically touch your cells.

    And you're aging out - nooooooooo ;D We need your knowledge around as long as possible brother! I jest, a good vacation from a life of hard work is always deserved!

    Before you go, mind hooking your brain up to this here computer for a download? ;D
    Last edited by CLRH2O; 07-12-2018 at 11:27 AM.


    CLRH2O (Clearwater) & SenseNet (Cheney)

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