Lithium Conversion (leaf battery)

[mutant]

Originally Posted by rottie

I agree with limited slip, but I would have to cobble one together. I have a 1994 marathon electric (dana H12?) and as far as I can tell no make a drop in replacement LSD.

Some one else mentioned they had done LSD with replacing the motor gear with a rvx version??? then add the LSD. I have not looked into the exact details.

As for front wheel drive, I am using my 2015 golf tdi to pull it out and it does slip the front tires a fair amount, but doable.
Mainly, I have someone goose the boat throttle to help push everything out and that works pretty well.
I know the real answer is get a 3/4 to 1 ton 4x4 and tow with that, but unfortunately that is on the left coast right now..

my buddy makes most of the LSD units in the continental tire series cars and might be willing to mod a stock diff for you-i can ask if you are interested...he can also do one for the tdi....

[Sergio]

Since You have such an abundance of AH.... how about powering some more motors for a quasi 4WD?

http://www.silverwolfmotors.com/pages/faq

[rottie]

Sergio:
I saw those motors and started dreaming. But that is out of the question.
The Boss (wife) wants the current project finished first.

I have two more modules being shipped right now and will reconfigure the battery pack to 42V at 180Ah (12S6P) from 67V 120Ah, (16S4P). Then put the throttle mapping back to original and see what max speed is then.
I don't mind popping wheelies , but I don't want to go 30+ mph.

Extra Ah never hurt and makes it so I can go much longer w/o constantly charging. Besides, it will be better as I am not pulling so much current from each module and they should last longer.

[JohnnieB]

Going from 16S to 12S is a 25% reduction in voltage and dropping the pack voltage by 25% will theoretically drop the top speed by 25%.

If it does 32 MPH now it ought to do about 24 MPH with the new battery configuration.

You'll also drop the amount of torque you now have by 25%, so it may not pop wheelies, or at least not as big of ones.

Range will probably be ridiculous.

[rottie]

Actually the torque will go back up (change throttle mapping) as I have the throttle mapping severely limited for the high voltage battery configuration.

Range, I hope will be totally ridiculous. That is what I like.

[cgtech]

Due to the deceptive "20 hour" rating method used for lead acid batteries (in my opinion), you should be about 125% of the capacity of 8x 6v T-105s, but carrying far less battery weight which will also help range.

[JohnnieB]

Another deceptive practice is the way the kWh stored in a battery is calculated. They use the 100hr rate, which is only 2.5A discharge for a T-105.

The 5hr rate for storage capacity is as close as Trojan gets to real world golf cart applications and it is only drawing 37A from the batteries.

At least US Battery publishes AH storage capacities down to the 1hr rate.
Some of the other manufactures publish even less info than Trojan.

[Volt_Ampere]

My 14 module Leaf pack weighs 120 pounds and is 120AH - at least 100 usable. That is about 250 pounds lighter than the batteries I replaced and I don't (and should not) have to charge them every time I use the cart. Down side is cost - about 2.5X.

[marianol]

Nice thread and great build Rottie!!!

My BI and Analytics background kicked in when I saw that CSV.. Here is a gift for you guys

https://spotfire.cloud.tibco.com/spo...2-90e6718a7d41

I did not have time to pull any fancy stuff but at least you can see the batt and motor current and volts over time with the throttle % imposed. Enjoy :)

By the way the slider in X axis allows you to zoom in time wise, and if you select points in the charts those will be shown in the table below with the rest of the data.

[Volt_Ampere]

Nice plots, marianol! What tool did you use to make them? I would like to make some like that with my data. I like the way you were able to overlay several plots and scale them so that they look good!