Southport LiFePO4 dealer

[GregsGarage]

I have added a picture above.

What current have you been pulling?

What Voltage sag have you seen so far?

Peter

At 50 mph I am drawing around 100 amps. Will pay better attention to voltage sag and report tomorrow 50, 100 and 200 amp sags. So far the most I have seen is around 2.75 volts per cell under hard acceleration (keep in mind that we are talking about a Fiat 126 so hard acceleration is a bit relative).

Greg

[GregsGarage]

I made some very crude measurements of voltage sag on my journey to work this morning. The current readings are taken from the e-meter and pack voltage from the Paktrakr. Each instrument only updates about once a second, and not at the same time! Also had to concentrate on driving and trying to hold a steady current reading in the not very flat Scottish Borders! Basically these are only a rough guide, your results may vary.

My pack is 24x 100ah cells. When I started my journey this morning they had already had 21 ah removed from the previous nights journey. The starting pack voltage was 80.3 volts.

__Amps______Pack voltage_____Cell voltage
___50__________76_____________3.2
__100__________73_____________3.0
__150__________71___________2.9 - 3.0
__200__________69___________2.8 - 2.9

At the end of my journey the e-meter read 41ah total removed from pack.
Resting voltage was 79.5 and after 1 hour had risen to 79.7

Greg

P.S. Is there a better way to make a chart?

[geekygrilli]

This is great info...

How many miles have you done to remove the 41Ah?

[GregsGarage]

This is great info...

How many miles have you done to remove the 41Ah?

22 miles

[retepsnikrep]

Looks like range about 50 miles then, not bad for quite a small pack

[MalcolmB]

Yes, that's really encouraging news.

So if I've understood right: 22 miles from just under 3 kWh means you're using less than 140 Wh/mile? Excellent

What was your average speed Greg and do you know roughly how much the Fiat weighs now?

[GregsGarage]

So if I've understood right: 22 miles from just under 3 kWh means you're using less than 140 Wh/mile? Excellent

What was your average speed Greg and do you know roughly how much the Fiat weighs now?

I am going to say 150 Wh/mile which is what I was aiming for, or 225Wh/mile at the wall.

Average speed 50 mph. Hoping to be able to work on the aerodynamics a bit and try to get that figure closer to 150Wh/mile at 60 mph.

Will get it weighed on the weighbridge and report back, but less than when it was a petrol, I think.

[MalcolmB]

I am going to say 150 Wh/mile which is what I was aiming for, or 225Wh/mile at the wall.

Average speed 50 mph.

That's really good news. I knew going for a lightweight conversion made sense, but that's even better than I expected. Just the incentive I need for my mini conversion

[EVguru]

My Scirocco used about 300Wh per mile (charger input) on my 10 mile commute down the M1.

[GregsGarage]

In addition to the light weight, several other things are helping the efficiency.

Lithiums seem to only reuire about as much current put back in that was taken out. My e-meter counts the ah back down to zero, when it hits 0 the charge has switched off. Lead acid require more to be put back in before they are fully charged

Cedric's excellent PM motor, still can't believe how small and light it is compared to the 9 inch motor in my Volvo (But the Volvo is much faster)!

Regen braking. I have connected this to the brake switch, so when I touch the brake pedal I get 50 amps regen which slows the car down nicely. There is a nice spot between the regen being activated and the brakes actually engaging.

Now to get my BMS working and tidy it all up.

Greg