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Old 05-21-2021, 09:55 AM   #21
Volt_Ampere
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Default Re: Is RoyPow a fake company??

@Pat911, I agree with you on all of that! The big drop in lithium battery prices was several years ago. The Leaf cell (and most other EV cell) chemistry does require more care to use it safely but there are lots of EV's on the road doing so. I like it much better for my use partly because it's relatively easy to measure SOC based on cell voltage. It's not deadly accurate but pretty good if you have good discharge data for your cells. This is very difficult with LiFePo4 cells because their discharge curve is much flatter. I have two carts running Leaf cells - one has been going for over four years now, the second I just built. These cells are nowhere near new condition but I can get three rounds of golf out of them and the four year old one has not degraded much through my use. I hope that by the time I need new ones there are other reasonable alternatives. I do not like any of the "drop in" or even the ones offered by the cart manufacturers. I would still prefer my "old very used" Leaf modules to any of those packages!
I built my own SOC meter based on cell voltages and the discharge curve for Leaf cells. I also have a Speedometer/Odometer that I built so that I know how far I have driven. I reset the "trip" every time I charge. I usually go about 20 miles between charges and it's at about 25% SOC then. If I had new Leaf cells, I would get much more range!
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Old 05-21-2021, 10:35 AM   #22
fstop
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Default Re: Is RoyPow a fake company??

Quote:
Originally Posted by Volt_Ampere View Post
@Pat911, I agree with you on all of that! The big drop in lithium battery prices was several years ago. The Leaf cell (and most other EV cell) chemistry does require more care to use it safely but there are lots of EV's on the road doing so. I like it much better for my use partly because it's relatively easy to measure SOC based on cell voltage. It's not deadly accurate but pretty good if you have good discharge data for your cells. This is very difficult with LiFePo4 cells because their discharge curve is much flatter. I have two carts running Leaf cells - one has been going for over four years now, the second I just built. These cells are nowhere near new condition but I can get three rounds of golf out of them and the four year old one has not degraded much through my use. I hope that by the time I need new ones there are other reasonable alternatives. I do not like any of the "drop in" or even the ones offered by the cart manufacturers. I would still prefer my "old very used" Leaf modules to any of those packages!
I built my own SOC meter based on cell voltages and the discharge curve for Leaf cells. I also have a Speedometer/Odometer that I built so that I know how far I have driven. I reset the "trip" every time I charge. I usually go about 20 miles between charges and it's at about 25% SOC then. If I had new Leaf cells, I would get much more range!
Cool that you could fab an SOC meter so precisely for use with your Leaf pack like that.

For those considering or using LiFepo4, I'd suggest a shunt-based coulomb counting meter for precise SOC monitoring. You can get them in the $40-$90 range that work really well. My current LiFepo4 pack came with a voltage based meter, but really it is useless (as Volt_Ampere points out). My previous RoyPow however had a coulomb meter built into the BMS for display on the included meter.

With my current pack / meter I can use the cart for 10-20 miles and charge some (I usually don't charge to 100%), use it again, charge some etc... and after a week or so I might charge back up to 100% before I use it for a longer period, and the meter (which counts up as it is charging) hits the 100% mark within 1-3 minutes of the charger shutting off. It has been very precise in my experience and I'd definitely recommend for LiFepo4.

One thing I noticed however with the FET-based BMS units, is that they draw some power if the pack is set to have output at the terminals. My RoyPow would drop a bar or so every 2 days or so IIRC, and my current pack drops around 1.4% / day sitting with output "ON". I had the supplier wire a port for a simple SPST switch to control BMS output, and turning off the BMS output with that drops idle pack loss to something so low I haven't been able to measure it. The RoyPow behaved similarly, meaning if you turned off the power switch there was no (or super low) drain while not being used.

That power drain isn't reflected in the SOC meter I use because the BMS is not on the load side of the shunt, but the RoyPow's configuration would, and that's why the meter would drop with the RoyPow.

With my current pack, if I leave the main switch "ON" all the time, the SOC meter will get behind a little over time, and show a little more remaining than there is, and when recharging to 100% the meter will show 100% when counting back up before the charger shuts off (but when the charge is complete, the meter and battery SOC are in sync again). But by normally leaving the switch "OFF", the meter stays within 1-2% at all times. The meter I use also shows current voltage, which is nice for keeping an eye on things as well.
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Old 05-21-2021, 11:06 AM   #23
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Default Re: Is RoyPow a fake company??

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Originally Posted by Pat911 View Post
What makes you think that cart batteries are anything special? All that is required for a drop in solution are cells of a high enough discharge capacity and a BMS that can handle the discharge current. Both are readily available off the shelf.

All these companies are doing is enclosing everything in a case and wiring up the BMS. Definitely not rocket science.

Cheers
Pat.
I'm not saying they're special, I'm saying that they're not mature enough for me to jump in. It's apparent the technology itself may be mature (plenty of guys building their own, reliable packs), but that's a lot different than mass producing a high quality, high first-pass yield, low return rate product at a viable price. I'm in manufacturing, so that's my perspective.

Manufactures and their processes are young (maybe they don't really know what they're doing while "enclosing everything in a case"?), their quality assurance seems to be suspect, and some of the customer service seems to be lacking. 3 strikes in the current lithium market from my evaluation. Especially at the cost of 2x+ FLA.

I'll enter the market when there is higher quality competition across the board and, hopefully, the cost of the technology reduces.
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Old 05-21-2021, 11:21 AM   #24
Volt_Ampere
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Default Re: Is RoyPow a fake company??

Coulomb counting is really the only way to do accurate SOC with Lithium - especially LiFeP04 but doing that well isn't easy either. Integrating the chopped battery current is somewhat difficult to do accurately. I have no experience with doing that myself. My odometer is as good as anything once I have experience with my batteries. My usage is fairly consistent so my range is also. If I have driven 20 miles, I know I have to charge before playing another round of golf.
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Old 05-21-2021, 02:56 PM   #25
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Default Re: Is RoyPow a fake company??

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LifeP04 would likely mainly make a lot of smoke in the event of a major failure, -vs- NCA or NMC lithium which are more likely to burn or 'splode.

I think RoyPow is "real" in the same way that so many "companies" are these days (Anker, RAVpower, etc...). It's just marketing, a website and a logo really. Providing service and having dealers is a new foray, though, and one I'm not sure they've really got a good handle on. A few forum members have had issues with packs and the dealers have taken care of them, though in some cases it took some time IIRC. There are probably some cases where that didn't happen though, but at least there is some kind of dealer network / warranty there.

I know the dealer I purchased mine from had sold a number of them before I got mine (and that was a year ago) and all his customers were thrilled with them at that time and he had not had any come back in. Not sure what his experience has been with them since then though.

I looked into building one using Leaf cells but the fire hazard potential and having to go with used, years-old cells didn't sit well with me so I opted for RoyPow. In that case it was zero support -vs- possible support the way I looked at it.
This statement 'in red above' is total crap when it comes to leaf modules. The link below will take you to a test run by Nick Tranakiev of EV Battery Center in Las Vegas, who was the main source of leaf modules, BMS and chargers from 2015-2017, for those who wanted to assemble their own pack. I built mine in September of 2015, today those modules, are all within .008V. Since my BMS is set to balance to .020V, the BMS really never has had to do much on my pack. Nick passed away from cancer in late 2017. But, this test will show you that there is no fire hazard from the leaf cells. Unlike Tesla or Chevy Volt. He disassembled a leaf module containing 4 cells and did this test on a single 4.2V pouch. When he gets to the part with the torch, the only way the flame stayed up, was when the torch flame was applied directly. Turn volume down as Nick's music attachment sucks

Note: Read the Nickmaster2 comment directly under the video.

https://www.youtube.com/watch?v=Jz37WycW-7E

Here is a link from a BGW member using Chevy Volt batteries, which will catch fire.

https://www.buggiesgonewild.com/show...m+battery+fire
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Old 05-21-2021, 05:48 PM   #26
Volt_Ampere
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Default Re: Is RoyPow a fake company??

As long as you don't drastically overcharge or underdischarge a Leaf module, it is quite safe to use in a golf cart. Using a proper charger and BMS is required. I'm fine with that but I have lots of battery experience and I am comfortable with electronics and high current power systems. Volt cells are no more likely to catch fire than Leaf cells IMO. Both are likely to go up if you drastically overcharge them. They are a very similar chemistry.
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Old 05-22-2021, 09:44 AM   #27
fstop
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Default Re: Is RoyPow a fake company??

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This statement 'in red above' is total crap when it comes to leaf modules.
Eloquently stated, but please bear in mind it's only my opinion, and I specifically included the word "potential" after "fire hazard", and noted that it "didn't sit well with me". Not that it shouldn't sit well with you, or anyone else.

I understand you've had lots of success with this type of cell and are clearly very skilled in your execution, and fully appreciate efforts have been made by the manufacturer to make them as safe as possible. I read much of the same info that you reference before making a decision.

But to reiterate - it is just my opinion that older/used Leaf cells (or Volt, etc...), where the use / charge / discharge history is unknown could potentially be less-safe than new enclosed LiFepo4 cells. That's just the conclusion I felt comfortable with.

I certainly don't claim to know all the answers on any subject, and fully admit as much, and appreciate being able to use the input here on the forum from so many knowledgeable contributors such as yourself to form my own opinions on various things.
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Old 05-22-2021, 02:24 PM   #28
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Default Re: Is RoyPow a fake company??

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Originally Posted by fstop View Post
Eloquently stated, but please bear in mind it's only my opinion, and I specifically included the word "potential" after "fire hazard", and noted that it "didn't sit well with me". Not that it shouldn't sit well with you, or anyone else.

I understand you've had lots of success with this type of cell and are clearly very skilled in your execution, and fully appreciate efforts have been made by the manufacturer to make them as safe as possible. I read much of the same info that you reference before making a decision.

But to reiterate - it is just my opinion that older/used Leaf cells (or Volt, etc...), where the use / charge / discharge history is unknown could potentially be less-safe than new enclosed LiFepo4 cells. That's just the conclusion I felt comfortable with.

I certainly don't claim to know all the answers on any subject, and fully admit as much, and appreciate being able to use the input here on the forum from so many knowledgeable contributors such as yourself to form my own opinions on various things.
fstop - Thank you for the kind response. I have used some of the lower capacity cells from Tech Direct before they imploded and stopped selling. All of them are doing ok but I can tell they are much lower in capacity.

I built a pack in late 2015 for a member from cells supplied by Nick and were tested at 64AH by him. About 3 months later, the member made a big mistake and went on vacation for a week leaving the KS on in the cart and the charger not plugged in. TOTAL pack voltage was down to 3.86V (.275V per cell) Talked to Nick and he had me connect a 36V standard EZGO PowerWise charger to the pack for a few minutes until the pack reached a high enough voltage for the Lithium charge to pick up and finish the charge. I had put a speedometer on his cart which maintains the total mileage driven. He now has over 2500 miles on the cart and can still drive over a mile to the course play 36 holes, come home and still have voltage to spare. The cells are still all within .020V balanced.

For another member, last year I built a pack for him from the lower capacity Tech Direct cells. It was fine until he let voltage get to the point that the cart stopped running. The lithium charger was able to recover the pack but range was soon diminished (damaged the cells like the pictures attached but only small expansion of modules) to where he could not get past 18 holes on a weekend. I managed to get lucky and find him 7 modules with much lower mileage (not from TD) and his cart is fine today.

My conclusion was that high quality cells could take more abuse than heavily used cells.

Another member with a double pack from 2016 cells from Nick moved to coast from Orlando in late 2018 after a lot of use on street and golf course. He let his cart sit unplugged from charger for about 6-7 months, until he called me. That pack showed total voltage of .001V on a Fluke 73. In other words 0V. I tried the Nick trick and the modules could not recover they expanded fast. I had to rebuild him an entire new pack.

These pictures are from that pack and the damage caused by heavier used modules and trying the Nick recovery. It didn't go well. After pulling the pack to disassemble, removing the first nut from the all thread sounded like a rifle shot and knocked the battery drill out of my hand. No fire or smoke, just puffed up like a blowfish. That is why I trust these modules not to be a fire hazard. Because of the Chevy Volt pack fire in the link earlier and of the Tesla fires all over the country, I would only build from Leaf modules. These days, any Gen2 modules found will be high mileage and far more susceptible to damage, but not fire.
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