CT&T E Zone range low

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timpootle
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Joined: Wed Mar 14, 2007 12:13 pm
Location: Chorlton-cum-Hardy, UK

CT&T E Zone range low

Postby timpootle » Fri Jun 28, 2013 10:42 am

I have attached a photo of our EV which readers may be interested in.

We bought it last year as promotional vehicle for our e-bike sales and to compliment our electronic development work

It is a CT&C E Zone originally made in South Korea. CT&C I am told are the world’s largest manufacturer of golf buggies and batteries.

They were due to be exported in large numbers to the States and the UK but due to some irregular financial dealings they decided not to proceed for the time being

Although the car had only done 50miles when we bought, it the 165amp hr batteries were dead, probably due to being left uncharged.

We replaced them with new 6 x 150 amp hr C20 Trojan T1275 12V flooded cell batteries which were the only ones that would fit in the tight space beneath the seats.

Battery weight 222Kgs Vehicle weight minus batteries 520 Kgs

Although the car accelerates well up to its maximum of 35mph we been unable to achieve a range in excess of 14miles. Range should be 30miles plus,

70 miles LI

The 7kw motor is a single speed 45v 3 phase 128amp rated, driving a transfer box to the rear wheels.

The charger is a Delta Q QUI 72V

The controller is a Sevcon Gen4

We contacted Sevcon to see if we could help us rectify the poor range by downloading a program to introduce regeneration etc.

They were not particularly helpful and wanted us to purchase their program for a stiff fee.



Short of changing the batteries to LI with a new charger and controller we are at a loss to explain the poor range. It is still poor even on the flat

If any of your experts has any information or ideas then I would be most grateful for their help,

Best wishes,

Reg Brown

Ashleigh House.

Ashmount Road

Grange-over-Sands

Cumbria

LA11 6BX

Tel office 015395 35786

Fax offfice 015395 34784

Tel works 015395 59195

Mob 07785538711

Web http://www.ashleighengineeringservices.co.uk

http://www.bespoke-ebikes.co.uk



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Tim Crumpton

mattcarr
Posts: 389
Joined: Sat May 12, 2007 2:27 pm
Location: Hampshire

Re: CT&T E Zone range low

Postby mattcarr » Fri Jun 28, 2013 6:09 pm

Hi Reg,

I have to say that range does seem very low. I had a gwiz, which had 8 * 200ah 6v Trojans in it ( 9.6kwh ) and I could get a good 40 mile range. I am surprised that you are only getting 14 miles out of it.

Is it a direct drive? or does it have any type of auto gearbox on it?

Are you able to take any type of voltage readings from the batteries when it is not going any further?

Matt

rbrown1
Posts: 3
Joined: Thu Apr 15, 2010 7:16 am

Re: CT&T E Zone range low

Postby rbrown1 » Tue Jul 02, 2013 3:03 pm

Hi Matt,

The drive is direct with acceleration brisk up to 35mph maximum
There is some regeneration on the overrun when descending steep hills volts rising to about 75volts
When cruising on the flat the voltage is about 69v at 30 to 35mph
Once it starts to climb steep hill the voltage can fall as low as 52volts depending on the state of charge
Driving at 25mph and accelerating gently does not seem to improve the mileage
The original batteries were 72v 165amp hr which we were unable to get and made do with 150 amp hr.

Regards,

Reg

User avatar
timpootle
Posts: 1361
Joined: Wed Mar 14, 2007 12:13 pm
Location: Chorlton-cum-Hardy, UK

Re: CT&T E Zone range low

Postby timpootle » Tue Jul 02, 2013 9:16 pm

You made it here! Glad you got sorted with your forum login, Reg. Next hurdle is to fix the car!
Tim Crumpton

mattcarr
Posts: 389
Joined: Sat May 12, 2007 2:27 pm
Location: Hampshire

Re: CT&T E Zone range low

Postby mattcarr » Wed Jul 03, 2013 7:38 am

Hi Reg,

Interesting that you say the voltage can drop as low as 52 volts under heavy load - this to me seems too low. That is 8.6 volts per battery. They should not drop that low - I suspect that you have got at least one bad battery in your pack - and the pack is only as strong as it's weakest member.

I would expect a good healthy 12 volt battery to not drop below 10.5 volts under a heavy load and for it to bounce back to 12+ volts off load. Now, if you have got one battery dropping to 0 volts, that means the rest of the pack is dropping to 10.5 volts. Do you have any way of measuring individual battery voltages at all?

Another possibility is that your battery pack is just not getting enough of a charge. I would expect it to read at least 80+ volts ( maybe as high as 84 volts ) when it is fully charged. You say on regen down a hill you see a voltage of 75 volts - this is only 12.5 volts per cell - so again, I don't think this is high enough. What is the voltage reading when it thinks it is fully charged?

Matt

rbrown1
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Joined: Thu Apr 15, 2010 7:16 am

Re: CT&T E Zone range low

Postby rbrown1 » Thu Jul 04, 2013 8:06 am

Hi Matt,

The SG of each individual cell were checked and were ok
We got the supplier to replace the new set of batteries when we first got the car but it made no difference.
Then we borrowed his high capacity charger. Still no difference.
The batteries this morning are reading 75.8v fully charged.The charging voltage is about 90 volts.
I will check the SG of each cell this morning and see what we have.
I think we need to trailer the car to test it in an area which is flat and not influenced by hills and see what the range is then.
The low volts I mentioned were measured when I was going up a steep hill about 1 in 8 at about 20 to 25 mph flat out.
The battery would be about 75% + discharged. I can cruise at 25 to 30mph giving a reading of 69 to 70 volts on the flat with a fully charged battery.
We are unsure if the controller is set up to deal with the 3phase 45volt motor. All the manufacturers of the controller could tell us was that it should do.
As we do not know of anyone with a similar car we are unable to compare.
.
Regards,

Reg

mattcarr
Posts: 389
Joined: Sat May 12, 2007 2:27 pm
Location: Hampshire

Re: CT&T E Zone range low

Postby mattcarr » Thu Jul 04, 2013 6:01 pm

Cruising at 25mph with a voltage of 70 means the batteries are less than 12 v each - this does not seem right. I would expect I higher voltage at such a low speed, or the low voltage maybe caused by one bad bettery in the pack.

Another thing to consider is the rolling resistance of the car. If it is bad then this will cause a shorter range, but not as low as you are seeing. I am going to dig out sotwist my old gwiz battery logs - I know I have some somewhere, as I think your batteries should hold well over 12.0 volts each under a reasonable load.

Matt

rbrown1
Posts: 3
Joined: Thu Apr 15, 2010 7:16 am

Re: CT&T E Zone range low

Postby rbrown1 » Fri Jul 05, 2013 6:20 am

Good morning Matt..

I have checked the cells which were almost fully charged ( SG reading ) and all were fine
I then tested the vehicle on the flat at 28 to 30 mph driving on the voltmeter and managed to keep the volts steady at
71.5 to 72.5 for the first 12 miles. At this point the gauge was reading empty. I pressed on for another two miles until the warning lights started to flash but I was still reading over 71 volts. Expecting to come to a halt at any time I pressed on for another 11 miles giving a total of 25 miles.At this point I was still travelling albeit at less than 25mph with battery volts below 60v
It just shows how easy it is to miss the obvious by looking for a more technical solution
We shall now discharge the electrical control system with fully charged batteries which should reset
the battery indication.
The next step is to try and get more charge into the battery, although we checked with the charger manufacturer who said the setting we are using is correct We shall try anyway
There is not much rolling resistance but the hill do make a significant difference to range especially as we have such heavy batteries. The most obvious solution is to replace the lead batteries with LI .
I should be getting a van version in the next month which will give us a comparison.

We still need to reprogram the controller to give us some regen on braking but without any information or circuit diagrams this could be quite a problem for our electronics engineer, son Alex.

Many thanks Matt


Regards,

Reg

mattcarr
Posts: 389
Joined: Sat May 12, 2007 2:27 pm
Location: Hampshire

Re: CT&T E Zone range low

Postby mattcarr » Fri Jul 05, 2013 7:24 am

25 miles with almost fully charged batteries - that seems much better. Also, with new batteries they do take a few cycles to bed in until you can get their full capacity out of them. As you are reading the SG on these - I take it they are wet cells. Another thing to take in to account is watering them - to make sure each cell in the pack has enough water in it, and to also from time to time do an equalisation charge on the pack, where they can bubble away for a while to ensure that all the cells are indeed fully charged.

As for rolling resistance - those hill things are rather pesky aren't they :-) unless you have a route where you are always going down one.
But, it is quite amazing how much difference it can make if you have the correct ( or higher ) tyre pressure, well aligned wheels, brakes that are not dragging - this can add several % points more range to the car.

Matt

mattcarr
Posts: 389
Joined: Sat May 12, 2007 2:27 pm
Location: Hampshire

Re: CT&T E Zone range low

Postby mattcarr » Tue Aug 06, 2013 7:01 am

Hi Reg,

I was just wondering how you are getting on with the car. Did you manage to reset your gauge at all? Are you getting good distance in the decent warmer weather?

Matt


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