Cool, thanks for the site history lesson. I get it. Info on LiFePo4 is very interesting. Everywhere I read it seems claims are LiFePo4 is best for more cycles and overall battery life. Is this only true for low current applications?
From the sellers. Yes, ok for solar. No EV builder uses LFP currently afaik. NMC is the way to go. Only price of Chinese made batteries make them attractive.
NMC
@DougK … are you in San Diego? (For some reason thought so). @dougl has one of the SDI 22 packs if you want to check it out.
That would be cool, then all you woul dneed is a “dougM” and a “dougJ” in san diego…
I can doug that!..
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Yes, I’m in San Diego. Would be very interested in checking out another setup that someone has working. Always nice to see the full setup and bigger picture to make sure I don’t trip up on something that someone else has already figured out!
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I think this has been answered and You already learned but I’m on a plane and I have a couple hours to kill. Fortunately I have WiFi.
I really like lfp chemistry and I think for Solar or energy storage is the best, it’s safe and it has plenty of cycles however for cars is a No No.
people are using them in golf carts, they might be ok too because they are not amps hungry as Gems.
Now I’ve personally seen these batteries perform in a GEM, dropping over 10v during acceleration making the gem trip, limp and act crazy…. they were 100Ah each. The guy replaced it with Sdis and it was a new car.
I would stay away From Lifepo4. go with Samsung Sdi from Dave, 7.6kwh 94ah, that has been tested and it just… Works.
(Trust me I’m the one of the ones that like to pee on the electric fence)
people are using them in golf carts, they might be ok too because they are not amps hungry as Gems.
Isn’t this statement exactly opposite? Lower voltage requires more amps to get the same work.
Or maybe you are considering golf carts are smaller/lighter so they do not require the same amount of (relative) work?
I’m running a set of LiFePo4 cells (the green ones) from @Inwo in my 2002 and they are great. Never experienced what you are describing. Fastest it’s ever been and have yet to find the range limit. Plus they are very low maintenance.
Those were usa made, possibly the exception to the rule.
High c rate last forever if they aren’t run dead.
100% lfp from China now.
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Standard golf carts. <3kw motor 12 mph.
A local picked up a franken battery. 36v. Left over 80a bms. Protected for charging only, was the plan. He runs the load through it.
An old resistor cart. Default was 80a, I do believe he got bms set higher, but runs fine drawing less than 80 amps.
I had him connect load through bms to see what motor draws. It was only a 40ah battery and wanted to see if it would get useful range.
Made it from an 8s bmw and two sdi cell returns.
Total retail was $250 iirc. With warranty of course.
Hence frankenbattery.
Found pic. Protected and non-protected leads on right.
Tags:
Dave’s junk box
What was I thinking
Cleaning house
Lg’s flood battery
Ended up getting the Samsung batteries, thanks for the advice! I did go with the 96V setup and installed the voltage reducer going to the controller on wire #1. Everything seemed good, but when trying to test drive for the first time after the first full charge I got a 77 error. Online that states it is a vehicle over speed error and that I should check the motor controller. Anyone ever experience this error before, and if so any thoughts on how to fix it?
I had the same problem when I put lithium in my 2000 with a t2 controller
for whatever reason, on that car and another 94v was the magic number. I couldn’t run over that without getting error 77.
Turn the headlights on to suck down the pack. Keep trying as the voltage decreases.
Ended up getting the Samsung batteries
Actually those look like the VW 24s setup? (LG’s Mighty Mite)
Do you have a T1 or T2 in there? It seems those have about a 50% success rate when pushing up to 24s(96v).
As Ernie said:
Turn the headlights on to suck down the pack. Keep trying as the voltage decreases.
Once you find that voltage set your BMS to shut off the charge cycle early.
Yes, nice fit but too high voltage for an early Gem. I would have suggested Samsung battery.
We make a front mount 7kwh and now 5kwh 74v and 80v model.
88v is just a little too high for your model. Fine for 2005+ that can run up to 98 volts.
Thanks. Kept the lights on and tried again every 30mins or so. Stopped getting the error around 94.8v. I’ve adjusted the BMS to cut off at cell voltage of 3.95v so I end right back up at 94.8. Hopefully that will take care of everything. Even without the top of the voltage curve the range seemed pretty good on my first test drive. Would probably have gotten about the same range as a new set of lead acid batteries, but now that I’m not charging all the way maybe the lithium batteries will last even longer?
Have a T2 controller. Charged twice (from voltage <87V) twice successfully, but then did a short drive and got the high out of voltage 77 error mentioned above, have been dropping the voltage back down to around 86V and now I’m getting this strange error. Attaching a link to a video of the Delta-Q LED sequence as it’s a lot of lights and hard to explain in words. Anyone have any thoughts on what to try from here? Thanks in advance for any feedback/comments!
Your description is a bit confusing. What is the status of the car now?
Does it still get the error even tho you dropped PackV down to 86v?
Or car runs but it doesn’t charge (giving you the confusing lights).
I can’t quite a read on those lights. Your vid was tough to see. Did anybody else try to cup their hand over their computer screen to block the glare?
Confirm your present V.
Confirm what profile you are running on your charger.
There is a chance you did not drop low enough for that profile to actually kick in. Some of those profiles act a little strange and won’t restart after a quick run around the block
Car runs, just won’t charge.
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Is this a 72v charger or a 96v?
What is your present PackV?
What profile is it set to?