New Icon with Lithium

[fstop]

Originally Posted by ATrain

Further, 72v is not compatible with these carts. The motor may be capable of handling it but the controller is not.

The controllers are rated at 48v with an "action voltage range" of 20~63V. So 72v would cause problems AFAIK.

Lithium, specifically LiFePO4 (lithium ion phosphate), is the way to go, but quality, reliability, price, and support are just not there yet in my opinion for these carts.

In the next 1-3 years though, I think that will change.

The motor doesn't actually see 72v DC AFAIK - the controller does but the motor is driven by AC (converted via inverter from that DC AFAIK) of some voltage and variable frequency, but your point I think is that the motor / controller as a unit isn't set up for 72v. Thanks for posting the details.

I would agree with your opinion that LiFeP04 reliability longer term is yet to be seen - could be a bit of a gamble. It is more expensive initially, but if it lasts as promised the numbers work out. I guess we'll see, but in the meantime the performance advantages are huge if that is of any importance (it was a major driver for me).

I was willing to roll the dice and not everybody is, which is understandable. I will say I used my RoyPow LiFeP04 for a year and never had any kind of issue, and I've had my current unit about 6 months or so. So far so good!

[mbrown55]

I bought my I60L with roypow lithium and no issues at all. Charge quickly and the range and power is amazing.

[ATrain]

Originally Posted by fstop

The motor doesn't actually see 72v DC AFAIK - the controller does but the motor is driven by AC (converted via inverter from that DC AFAIK) of some voltage and variable frequency, but your point I think is that the motor / controller as a unit isn't set up for 72v. Thanks for posting the details.

I would agree with your opinion that LiFeP04 reliability longer term is yet to be seen - could be a bit of a gamble. It is more expensive initially, but if it lasts as promised the numbers work out. I guess we'll see, but in the meantime the performance advantages are huge if that is of any importance (it was a major driver for me).

I was willing to roll the dice and not everybody is, which is understandable. I will say I used my RoyPow LiFeP04 for a year and never had any kind of issue, and I've had my current unit about 6 months or so. So far so good!

Yes, I think you're right since these are brushless AC motors. The controller though would have to be able to handle that voltage, which from my reading of the specs says it can't. I'm no expert though, so no clue what would happen if somebody wanted to try it lol.

The big thing with the LFE batteries is just QC (quality control). QC from the cells origin and QC from whoever assembles everything. Are things properly vented? How are the cells connected and are they connected properly? Is the BMS configured properly? Etc.

That Will Prowse kid needs to do a tear-down on a RoyPow and give some feedback.

I've seen YouTube/FB videos of people w/RoyPow packs and major issues and then I hear on the forums first hand accounts with no issues at all. I want to know the failure rate and failure source. Is it a stupid problem that can be fixed at home or just defective cells?

Still feels Wild West to me, but I'm happy to watch/learn from those willing to be the early pioneers!

[fstop]

Originally Posted by ATrain

Yes, I think you're right since these are brushless AC motors. The controller though would have to be able to handle that voltage, which from my reading of the specs says it can't. I'm no expert though, so no clue what would happen if somebody wanted to try it lol.

The big thing with the LFE batteries is just QC (quality control). QC from the cells origin and QC from whoever assembles everything. Are things properly vented? How are the cells connected and are they connected properly? Is the BMS configured properly? Etc.

That Will Prowse kid needs to do a tear-down on a RoyPow and give some feedback.

I've seen YouTube/FB videos of people w/RoyPow packs and major issues and then I hear on the forums first hand accounts with no issues at all. I want to know the failure rate and failure source. Is it a stupid problem that can be fixed at home or just defective cells?

Still feels Wild West to me, but I'm happy to watch/learn from those willing to be the early pioneers!

I think you're exactly right on all of that.

I knew when I purchased the RoyPow it was somewhat of a gamble, but I had zero issues. I did see inside one once and it was manufactured incredibly precisely, with serious attention to detail. No thrown together smoke bomb there. I was impressed.

They (RoyPow or other packs with same or similar cells and FET-based BMS units) just haven't been around long enough to know what the 3-10 year down the road situation would likely be - so that's the real gamble IMO.

But switching to the 51v pack from lead-acid was a serious night and day difference all around in my case (a CC Onward, not an Icon). Range essentially doubled, and never ever hit limp mode, which with my LA set would happen pretty quick if you drove aggressively much. Speed and acceleration also had obvious improvements. Moving to 72v (essentially same pack design and BMS type) just made the midrange and acceleration completely effortless -vs- even what the 51v did. Top end is overkill. I can say that with respect to performance, range, maintenance and charge speed / ease I would never consider going back to lead-acid. The other side of the coin is I think you have to accept that to get all that there is the Wild West thing you mention, but I'm ok with it.

That said, I'll keep my fingers crossed but I made sure a spare BMS was included when I had my current pack configured, as I think that is probably the most likely point of failure going forward, esp. with higher amp-draw use cases.

BTW, it looks like the Icon may be ok with 60v nominal based on your info (is there somewhere in the controller PC program where you can set nominal pack voltage? Solenoid coil output voltage?), and I think that's a pretty good compromise if somebody is having a pack configured. I just don't know the Toyota controller specifics, but the Navitas tech guys had indicated some while back to me that the DC>AC inversion process could / would be more efficient at 72v -vs- 48v. I can't imagine it would be a huge difference in efficiency, but the lower amp-draws if nothing else reduces heat in the whole power delivery system.

[fstop]

Originally Posted by mbrown55

I bought my I60L with roypow lithium and no issues at all. Charge quickly and the range and power is amazing.

Did you go with the 105ah unit? That's the one I had, and it did really well.

Did you have that installed from the beginning or change out your FLAs for it?

Also curious if you ever hit "limp" mode with this battery?

[mbrown55]

I've gone 47 miles in my I60L with 3 large adults in hilly terrain and had plenty of reserve when I got back, about 40%. Lithium is the only option for me, I've had too many friends ruin their garage floors with acid boil over.

[mbrown55]

i bought my I60L new with lithium and couldnt be happier. Was about a 2500 premium but worth it in my book. Very fast charging, extremely long run times, they have been very reliable and no worry of acid on the garage floor or damage to my cart from boil over.

[HDaugus]

Having researched the Icon/Lithium combination we came to the conclusion that the technology of the carts hasn't quite reached a good match for lithium batteries. It may be okay if you only drive on flat areas, but for those who live in a hilly area, the cart can seize up and just stop suddenly, particularly right after a full charge. Our driveway is on a hill so we have no choice but to go downhill right after charging so we went with lead acid. Have been 100% satisfied with the lead acid experience. Our 2021 i40L does the hills like a champ. The range isn't bad. I went 20 miles today including a lot of hills and I arrived back home with 70% still on the battery indicator. We're adding solar panels to the roof soon to extend the range ;) And maybe someone will sort out the lithium seizing issue at some point too.

[bronsonj]

Originally Posted by HDaugus

maybe someone will sort out the lithium seizing issue at some point too.

The lithium seizing issue is just the BMS.

If you build your own pack it's not a problem, you just have to be comfortable with higher voltages and be cautious. The $40 BMS boards will work just fine if you use the cutoff circuit of the BMS to control the solenoid instead. This way the BMS only sees the current needed to operate the solenoid, not the full amperage.

I'm excitedly waiting for the solid state lithium batteries. That'll be a real game changer for so many industries, including golf carts. I'm very happy with my Lion (Lithium Nickel Manganese Cobalt traction batteries from a Chevy Volt). I charge to a max of 57.6v so it sounds like the ICON can handle that just fine. My cart had a HUGE performance improvement by going up in V and down about 400lbs in weight.

My hope is my current lithium battery lasts 10 to 15 years and that solid state lithiums are available when my current pack no longer has sufficient capacity.

[ATrain]

Originally Posted by bronsonj

The $40 BMS boards will work just fine if you use the cutoff circuit of the BMS to control the solenoid instead. This way the BMS only sees the current needed to operate the solenoid, not the full amperage.

Can you elaborate on this more?

The issue, as I understand it, is that the controller sends some amount of power to the motor to keep the electric brake disengaged. If the BMS detects an event and shuts down, all power to the controller is lost and the electric brake immediately engages.

The electric brake is like a metal plate on the end of the electric motor with a magnet or something that, with a resting position of brake engaged it seems.

I'm not following how the BMS operating the solenoid would solve that, but I don't understand what the cutoff circuit does either.