Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Do you own or use a EV. Then this is a good place to discuss things.
wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Wed May 31, 2017 5:56 pm

Hi folks,
I am just approved to this forum so I hope I got this topic in the right 'subforum'. I am a student at Kingston University and just started with my dissertation. The aim of my dissertation project is to design the replacement system for the battery in a Axiam Mega Van with an Hydrogen Fuel Cell system. To do this I need to know what type of the original battery is. I know there supposed to be 8 or 12 gel batteries in there which I got from datasheets on this website http://www.megavan.org/mega-van.htm. But the datasheet doesn't say which type. Can anyone maybe tell me what type is of the original battery pack? I need it to figure out what the dimensions, capacity, charge current, discharge current, well basically all characteristics of the battery will be for my Hydrogen Fuel Cell system.

The car is actually located at our campus, but I don't have access to the car until next week and want to continue working on it during the weekend.

Thanks for any help!
Wout

wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Fri Jun 02, 2017 10:15 am

Hi all,
I had contact with http://www.rossefield-aixam.co.uk/ who were able to help me get the standard type of battery:
ABT 6-DM-76 (http://www.abtbatt.com/PDF/6-DM-76.pdf). I am quite happy with this! But the following problem is how the batteries are located in the Mega Van. I assume it will be in order of 4 x 3 (with 12 batteries), which total dimensions of the battery pack makes 696mm x 795mm x 226mm (L x W x H). But it would be even better if I knew the exact dimensions of the available battery storage in the Mega Van.

Does anyone have a Aixam Mega Van and/or knows the available battery storage in the bottom of the Van? Any help would be welcome!

Thanks,
Wout

Grumpy-b
Posts: 985
Joined: Sat Dec 01, 2007 12:06 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby Grumpy-b » Wed Jun 07, 2017 3:30 pm

Yes three lines of 4 battery, some installed from under the rear floor and some inserted from under the passenger seat. Its a steel frame slung between the chassis rails. As with any fuel cell vehicle you will still need a battery pack to start the vehicle and deal with the peak demands.
Why a fuel cell, given that access to hydrogen is virtually impossible (Unless you get it bottled and thats costly) the cost would be so huge and the safety issues of the stored Hydrogen on board are significant (Thats one reason why so few Hydrogen powered vehcicles are out there).

wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Thu Jun 08, 2017 11:01 am

Hi Grumpy-b,
Thanks for your reply! I've examined the car yesterday and came to the same conclusion. The cart where I will work with will be used on my university where there is plenty of hydrogen available, plus there are already (and being build) 5 hydrogen refuelling stations in London. Either way the aim is to focus the hybrid PEMFC module more for the passenger carts in airports. A number of airports already include hydrogen refuelling stations with most transport vehicles running on hydrogen.

And I like to kindly disagree on the safety issue ;). If you dig deeper into the current safety circumstances for hydrogen vehicles and refuelling stations you will notice that petrol vehicles are actually more dangerous than Hydrogen vehicles. I've been to a hydrogen refuelling station, drove in a hydrogen car, experimented with Fuel Cells and talked into the safety regulations.

I do have another question. I'm trying to figure out what the Hybrid PEMFC module need to produce as peak power and nominal power, but can't really find any information on the EVE system 1ME222A, which is (I assume) the main vehicle power controller. The box is located under the hood next to the DC to DC converter and motor controller. Does anyone have a datasheet or any information about the box?

Thanks for helping!

Grumpy-b
Posts: 985
Joined: Sat Dec 01, 2007 12:06 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby Grumpy-b » Thu Jun 08, 2017 1:09 pm

The safety issue is that of the integrity of the hydrogen container in a vehicle accident. If they get damaged the result is a significant destructive explosion. So far the Tanks for vehicle use are either generic small containers, or seriously costly specially made devices.
As to the Aixam, the motor control is from the Curtis controller, and potentially its a current demand of perhaps 150 to 200a peak. Current is hogher owing to the low (48v) pack voltage.

wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Mon Jun 12, 2017 2:37 pm

Hi all,
@Grumpy-b, thanks for the tip! The design includes the design of the frame surrounding the parts, I will definitely look into the standards of what impact it should withstand and maybe improve the impact ratio.

As for the Curtis controller, I've just read the controller manual. Thanks for the information about the rated current. I'll try to focus on that. If there is anyone who knows the specific rated current/power and peak current/power demanded by the controller or given by the battery, it is more than welcome. I also read that the Curtis controller is able of regenerative braking. Does anyone know what maximum charge current is whilst braking? I know that the charge current from the charger is 30A, but If the regenerative braking will exceed this I should focus on that.

Other than that, does someone know the gear ratio of the gearbox? Maybe I can derive the current demand from the motor speed and torque @ 30mph.

Thanks, Wout

Grumpy-b
Posts: 985
Joined: Sat Dec 01, 2007 12:06 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby Grumpy-b » Mon Jun 12, 2017 2:58 pm

Its not that easy.
1. you have a selector to choose low or high performance (Thats relative) in the cab,
2. The 8 cell version will not only have lower range but lower performance as the lead cells have a limited discharge rate. The higher the current the greater (Rate of drop and voltage) the voltage drop. The less the charge left in a lead cell the greater the voltage drop under load.
3. Regen is not the best on a DC sepex motor, and is limited to the lead acid cells which wont take as much as quickly as say a lifepo4 cell, and so act as almost a resistance giving speed reduction but not actually recovering too much.
4. Regen current will depend upon speed and the load (Therefore the kinetic energy) contained in the vehicle able to generate power. Higher load , higer speed = greater regen potential.
5. Too high regen will take the controller to cut back.

wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Mon Jun 12, 2017 6:24 pm

Hi,
@1: Oh, I didn't notice that yet. Thanks for the info! I assume the low and high performance must be connected to two of the four MultiMode options mentioned in the datasheet/manual of the Curtis controller. I will get into this and choose for the high performance as worst case scenario.
@2: I don't quite understand what you mean with:
The higher the current the greater (Rate of drop and voltage) the voltage drop.
Do you mean that, at the point that most charge is drawn from the battery, a high demanded current can cause a high voltage drop?
@3: Well, I need to choose an additional battery for my system, which probably will be a lithium instead of a lead acid as it needs to charge quickly.
@4: And I guess the angle of the road is another factor ;). But good to consider indeed.
@5: Yes and that is exactly what I like to know. I mean I lik to know what the maximum regen current is that the controller allows. The manual (http://curtisinstruments.com/Uploads/DataSheets/1244%20(13E)1.pdf pp. 36 'M1–M4, BRAKE C/L' says that this limit is adjustable from 100A up to the rated current of the controller type, which is 450A (from appendix C, type is: Curtis 1244-5461).

About the maximum set charge current, do you think it can be considered to be equal to the maximum charge current from the battery pack as the datasheet (http://www.abtbatt.com/PDF/6-DM-76.pdf) says? Which should be (12A*3batteries serie=) 36A? Or can a gel battery take higher charge current for shorter times? Say 100A for a 10 second duration.

Thanks for helping me out!

Grumpy-b
Posts: 985
Joined: Sat Dec 01, 2007 12:06 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby Grumpy-b » Mon Jun 12, 2017 8:26 pm

WIth a lead acid the higher the rate of discharge the faster the voltage drop, the faster the rate of voltage drop the higher the current.
Thats why lifepo4 etc are so good because they dont suffer the constant voltage drop so performance and current can be well controlled. Lifepo4 etc can deliver 3 to 5 or even some can do 10 c discharge.
That is also why Lead acids have multiple strings, they cant do much over 1c discharge without significant voltage drop. So you need way over the ah capacity to deliver a specif a . SO if you wish to draw say 150a you would probably need approaching 300ah to enable that to be delivered.
If you charge a lead of any type at a C rate higher than specified they will generally gas .Thats also why serious lead driven evs tend to use wet lead rather than gel . ie Things like the Polaris Ranger/ John Deere Gator.
Lead cells are either designed to deliver high current for short duration and get quickly recharged, like a starter battery. But cant be discharged and recharged . Whereas a leisure / traction battery can be fully discharged and recharged but often at a lower rate.

wout991
Posts: 6
Joined: Wed May 31, 2017 2:05 pm

Re: Axiam Mega Van - Hydrogen Fuel Cell as replacement for the battery

Postby wout991 » Tue Jun 13, 2017 11:06 am

Thanks for the information! That is a good thing to consider when choosing the backup battery in my system. And that is why most Fuel Cells are combined with ultra capacitors I guess: to deliver a high discharge current. Thanks for the information, I really appreciate it!


Return to “Cars,Vans and other road vehicles”

Who is online

Users browsing this forum: No registered users and 3 guests