Voltage and current meter

[ThreeCW]

I have been taking it pretty easy as I break in my new lead acid batteries. Up hill on our gravel road, I try to keep it under 100 amps. That is going pretty slow ... probably 3 mph. On the flat gravel road at the same speed, about 50 amps.

I did some amperage testing last winter when I was planning to go to lithium (this was from: http://www.buggiesgonewild.com/elect...batteries.html), with the following results:

I did some current testing on my Cushman using a Fluke 325 Clamp Meter as follows:
- Metering point = 2 AWG battery cable between battery 7 and 8
- Cart Base Weight (with driver) = 1850 lbs
- Cart Loaded Weight = 2800 lbs (loaded with 950 lbs of feed bags)
- Drive wheels equipped with tire chains (giving traction but added rolling resistance)
- Outside Temperature = 1 C (34 F)
- Cart was previously stored inside garage at 5 C (41 F) … assumed starting battery temperature

DC Amperage Testing Results as follows:
Flat Road (packed snow on plowed gravel road)
- Soft Start = 100 amps at base weight
- Full Acceleration Start = 280 amps at base weight
- Cruising at ~5 mph = 50 amps at base weight / 75 amps at loaded weight
- Cruising at ~10 mph = 100 – 120 amps at base weight / 80 amps at loaded weight

Uphill Road (packed snow on plowed gravel road)
- Soft Start = 120 amps at base weight
- Cruising at ~2 mph = 125 amps at base weight / 150 amps at loaded weight
- Cruising at ~5 mph = 200 amps at base weight / 300 amps at loaded weight
- Flat out (+5 mph) = 250 amps at base weight / 300 amps at loaded weight

Flat Terrain With Snow (6” deep lightly crusted snow on lawn)
- Soft Start = 150 amps at base weight
- Cruising at ~2 mph = 150 - 200 amps at base weight / 180 - 200 amps at loaded weight
- Cruising at ~5 mph = 250 - 400 amps at base weight / 380 - 400 amps at loaded weight

Analysis:
- This amperage testing was done to determine the battery discharge requirements if a lithium battery system was installed in the future.
- The above testing is not my typical operating conditions but does simulate the maximum continuous amperage that could be experienced during extreme operations.
- Given the above results, a lithium battery continuous discharge requirement of 400 amps would be required to stay within the safe operating capacity of the batteries.
- Given my preliminary review of lithium batteries, it might be difficult to “economically” achieve this 400 amp continuous discharge requirement.

[ag4ever]

Originally Posted by ThreeCW

I have been taking it pretty easy as I break in my new lead acid batteries. Up hill on our gravel road, I try to keep it under 100 amps. That is going pretty slow ... probably 3 mph. On the flat gravel road at the same speed, about 50 amps.

I did some amperage testing last winter when I was planning to go to lithium (this was from: http://www.buggiesgonewild.com/elect...batteries.html), with the following results:

I did some current testing on my Cushman using a Fluke 325 Clamp Meter as follows:
- Metering point = 2 AWG battery cable between battery 7 and 8
- Cart Base Weight (with driver) = 1850 lbs
- Cart Loaded Weight = 2800 lbs (loaded with 950 lbs of feed bags)
- Drive wheels equipped with tire chains (giving traction but added rolling resistance)
- Outside Temperature = 1 C (34 F)
- Cart was previously stored inside garage at 5 C (41 F) … assumed starting battery temperature

DC Amperage Testing Results as follows:
Flat Road (packed snow on plowed gravel road)
- Soft Start = 100 amps at base weight
- Full Acceleration Start = 280 amps at base weight
- Cruising at ~5 mph = 50 amps at base weight / 75 amps at loaded weight
- Cruising at ~10 mph = 100 – 120 amps at base weight / 80 amps at loaded weight

Uphill Road (packed snow on plowed gravel road)
- Soft Start = 120 amps at base weight
- Cruising at ~2 mph = 125 amps at base weight / 150 amps at loaded weight
- Cruising at ~5 mph = 200 amps at base weight / 300 amps at loaded weight
- Flat out (+5 mph) = 250 amps at base weight / 300 amps at loaded weight

Flat Terrain With Snow (6” deep lightly crusted snow on lawn)
- Soft Start = 150 amps at base weight
- Cruising at ~2 mph = 150 - 200 amps at base weight / 180 - 200 amps at loaded weight
- Cruising at ~5 mph = 250 - 400 amps at base weight / 380 - 400 amps at loaded weight

Analysis:
- This amperage testing was done to determine the battery discharge requirements if a lithium battery system was installed in the future.
- The above testing is not my typical operating conditions but does simulate the maximum continuous amperage that could be experienced during extreme operations.
- Given the above results, a lithium battery continuous discharge requirement of 400 amps would be required to stay within the safe operating capacity of the batteries.
- Given my preliminary review of lithium batteries, it might be difficult to “economically” achieve this 400 amp continuous discharge requirement.

I would suspect the amp draw would go down with lithium as the cells weigh less, and have lower internal resistance. Also, the voltage is higher making the motor a bit more efficient.

I don't think it would go down drastically, but I would not be surprised to see a 10 - 15% reduction, maybe even more.

[Winston Ellis]

That’s an awesome write up. Very informative. Looks like I will need a minimum 300A shunt for my cart


Sent from my iPhone using Tapatalk

[dundeebarnbuggy]

The Blue Sea meter comes with the appropriate shunt. You only need to supply the wire.

[NCPW]

How long did you sustain the 400 amp draw???

A double pack of leaf modules will give you all the amp capacity you would need. Plus, like ag4ever mentioned, your amp demand will go down with the decrease in weight.

[ThreeCW]

Originally Posted by NCPW

How long did you sustain the 400 amp draw???
A double pack of leaf modules will give you all the amp capacity you would need. Plus, like ag4ever mentioned, your amp demand will go down with the decrease in weight.

During my testing, I probably held the 400 amp draw for 30 seconds with my old lead acid pack.

I have been unable to verify the Leaf module ratings, as there seems to be limited manufacturers information published on Leaf cells.

[ag4ever]

Originally Posted by ThreeCW

During my testing, I probably held the 400 amp draw for 30 seconds with my old lead acid pack.

I have been unable to verify the Leaf module ratings, as there seems to be limited manufacturers information published on Leaf cells.

Before his passing, nick did extensive testing of the leaf cells.

https://evbatterycenter.com/HAC4/ind...=72&Itemid=631

You can also find links to different studies on the cell capacity, longevity, heat impact on lifespan, and other data from his website.

You will not find formal capacity and current ratings from Nissan, as these are not intended for use outside the Leaf. Nissan has no intentions on becoming a battery supplier for hobbyists. All data must be collected from people that test the cells themselves, and I don’t think anybody tested them as thoroughly as nick.

Neli is running the site now.

If you are pulling 400 amps sustained, you need the 14 module setup. At 400 amps sustained, you would drain a 14 module pack in about 10 minutes +/-.

A 14 module pack has about the same usable energy capacity as a set of extended run FLA batteries. How long can you drive your cart currently on a charge? With that info, you can figure out your average amp draw (approximately).

[Aflyer]

ThreeCW,
Great thread, lots of good information.
I am putting together an old Caroche based Vanguard Sport Coupe, and am trying to find an amp meter.
Did you find any others when you were searching? I would like to find one for the existing 2" round hole in the dash.
I have attached a picture of the original amp gauge with has about 10 gauge wires that were disconnected. Because of the wire size, I don't know if they were wired directly to the battery pack, and there was no shunt anywhere on the car.

I already have the SOC gauge for the voltage side of things.

Thank you,
Aflyer

[ThreeCW]

Originally Posted by Aflyer

I am putting together an old Caroche based Vanguard Sport Coupe, and am trying to find an amp meter. Did you find any others when you were searching? I would like to find one for the existing 2" round hole in the dash.

Some other BGW member have used the Victron Energy meters in their carts and they seem to be getting some positive reviews. They are very high tech ... and kind of pricey too.

See post #28 and onward to get some more information: http://www.buggiesgonewild.com/elect...ml#post1566104

The Blue Sea meter that DundeeBarnBuggy and I use will fit into your 2" hole ... or perhaps 2-1/8" ... would have to look it up.

[Aflyer]

ThreeCW,
Thank you, checked out the thread, and the Victron Energy gages.
Very nice stuff.
Aflyer