Comments about your Lithium Battery

[Tom47]

Originally Posted by DaveTM

It's been some time since I installed my new Alltrax SR 48500 controller. It replaced my previous Alltrax...IIRC...600amp controller. (Old controller puked after ten years...not too shabby!!)

In reading through this post....now I'm curious as to what I actually set my max amp draw on my new Alltrax 48500. I'll check that.

I know only of Alltrax (and not other controller manufacture's) but you can hookup a laptop... take your cart for a ride and obtain a second by second spreadsheet file that tells you more information than you want to know.

In my case I took my "hunting cart" (more a need for torque than speed) on a ride with the laptop hooked up. I went up a very steep hill and found out the "max" draw of amps was 345. So, IIRC I set the Alltrax to limit the max amp draw to roughly 300amps.

I took the cart up the same hill and noticed no difference in performance from the motor "asking for" the 345amp, but the controller only allowing 300amps. ....You know...like a kid asking for a quart of ice cream....but you give him\her a "more reasonable" portion.

I'll need to double check what I set the BMS max output to. IIRC I set the BMS max output to be somewhat higher....as a backup....in case the controller get's "wonky" (a very technical term) and doesn't do it's job.

I set the max amp draw in order to provide more available power to get longer ride distance from a full charge.

FWIW

That's a lot of amps, something I would never see in my area.

My EB 72 couldn't handle it for sure at 175 max continuous. But if I throttled the Alltrax down to 170 max motoring amps, I wonder what it would do on that hill.

Maybe I could tow a trailer to simulate a hill and see what the difference is.

[DaveTM]

Originally Posted by Tom47

That's a lot of amps, something I would never see in my area.

My EB 72 couldn't handle it for sure at 175 max continuous. But if I throttled the Alltrax down to 170 max motoring amps, I wonder what it would do on that hill.

Maybe I could tow a trailer to simulate a hill and see what the difference is.

I'm far from an engineer.....but towing a trailer may not provide the same amp draw....I dunno. I think the motor would draw the necessary amps to get "rolling" and once there (rolling) it would need "incrementally less" amps to go faster.

But....I'm just thinking out loud.

Here's a few screen shots of the data my Alltrax provided back in 2018. I may have mis-spoke about the max amp draw coming up that steep hill located behind my house. The "max" draw was 392amps and that was for a brief second....but amp draw over 300amp coming up the hill isn't unusual.

So, setting the max amp draw allowed to the motor.....if the motor calls for more amps (like in my data) limiting it to a high 200 amount leaves more "gas in the tank" while the cart still provides enough performance to get up the hill!!

[Tom47]

Thanks for the reply. You're probably right about the trailer but I was thinking just the first few seconds after taking off.

I see yours was over 300 for only 3 or 4 seconds. I would venture to say a good drop in pack, like Eco Battery 72Ah would be able to handle a situation like yours. It provides 600amps for 3 seconds and 300 amps for 30 seconds.

Hopefully this info will help someone in hilly areas make a lithium decision.

[scottyb]

The amperage draw decreases as the voltage rises. The momentary 392 draw you showed was at 42v. And I see a low of 39v ouch = possible readings on bad batteries. Typically the Lithiums are much higher resulting on less amperage drawn for the same task.
I have my long stack 14hp motor/ big tire cart/ 500 amp set at 300 MAD. And I have yet to feel it hit the cut off... of course it is 300#s lighter and several volts higher than it was with conv. batteries.

[Tom47]

Originally Posted by CP241

That’s okay. My new cart is lead acid. I charged it when I got it and I’ve driven approximately 35-40 miles since I got it and it is still at 100% state of charge. I’m pretty sure it’s good for another several hundred miles without charging it up again.

Maybe, but your weather is getting colder now. I'll bet you won't see more than 200 more miles.

(BTW, trailering a cart behind your truck doesn't count!)

[CP241]

Originally Posted by Tom47

Maybe, but your weather is getting colder now. I'll bet you won't see more than 200 more miles.

(BTW, trailering a cart behind your truck doesn't count!)

No it’s special. It has a charging “button”. I don’t need it very often, but every once in a while you give it a tap when it’s been sitting overnight and then you’re up and running. From there it charges itself as you drive

[Tom47]

Originally Posted by CP241

No it’s special. It has a charging “button”. I don’t need it very often, but every once in a while you give it a tap when it’s been sitting overnight and then you’re up and running. From there it charges itself as you drive

You got me this time.

But remember, this is the Club Car electric forum. No fair sneaking a noisy cart in here. Us half-a-sleep members will get annoyed.

[CP241]

Originally Posted by Tom47

You got me this time.

But remember, this is the Club Car electric forum. No fair sneaking a noisy cart in here. Us half-a-sleep members will get annoyed.

Don’t worry, I’ve still got an electric one too. Both have their advantages and disadvantage

[Tom47]

Originally Posted by CP241

Don’t worry, I’ve still got an electric one too. Both have their advantages and disadvantage

You mentioned a while ago you were thinking about a gasser for winter. I'm glad you found one.

I've been noticing a lot of them around here lately. In town, there are maybe 2 gassers for one sparky as we ride. I never noticed that many before.

Now you have the best of both worlds!

[DaveTM]

Originally Posted by scottyb

The amperage draw decreases as the voltage rises. The momentary 392 draw you showed was at 42v. And I see a low of 39v ouch = possible readings on bad batteries. Typically the Lithiums are much higher resulting on less amperage drawn for the same task.
I have my long stack 14hp motor/ big tire cart/ 500 amp set at 300 MAD. And I have yet to feel it hit the cut off... of course it is 300#s lighter and several volts higher than it was with conv. batteries.

The spreadsheet you see on my post was from 2018....when I installed my initial Leaf 7 module pack. I would guess it was at best a 60 amp\hr pack. At the time, and this was before "drop 'n drive" lithium batteries, I wasn't going to spring for a 14 module pack as I wasn't sure of the performance of a lithium pack.

However, I was so pleased with the initial 7 module pack that in 2020 I added another 7 modules to the initial pack.

The chemistry of Leaf batteries are different than these new drop 'n drive packs. I monitor my Leaf pack via looking at the remaining pack volts when it's at a stop. To me, the SOC% is meaningless. When my pack get's close to 50V at a rest...it's time for charging as the pack is right at the crest of the knee...and the LV relay is gonna trip very soon. And the KEY here is the battery pack at a state of "rest"...which would be the cart stopped for at least 2-3 minutes. Not the one-second "rest" that appears in the controller data.

It's also apparent from the data that a full pack charge is\was 57V....so when this data was obtained, the pack was nearing the low point of it's SOC....or "remaining voltage". It's also apparent that the LV setting was going to trip soon as the lowest minimum VPC would be 2.5v which would be a pack voltage of 2.5x14=35V. Anything below 35V would result in permanent damage to the cell.

So, the pack voltage you see dropping to 39V when pulling BIG chunks of amps is not all the big of a deal and certainly not any indication of a Leaf build pack having a "bad batteries". The motor can draw all it wants (the reading was before a max amp draw was even set in the controller) and when you are comparing drawing from a 7 module pack vs a 14 module pack....for sure the voltage is going to drop further in the smaller, less available energy of the 7 module pack.

So, it's battery chemistry....and amount of energy storage in the total pack. I now have twice the modules than I did in 2018...and BTW, 7 of my packs 14 modules are those original ones that I was running in 2018....and the pack still holds up very well and under conditions of extreme cold (below 20's) and on terrain that is only beat by the mountains of West Virginia. Where you live in Southern Kalifornia and what you consider mountains may comparatively speaking be nothing more than what we consider a "mild rise" in the terrain. As for cold temp's of S. Kalifornia...I doubt you're doing much hunting in 13 degree weather.