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Post by biggkidd on Jul 22, 2022 15:41:05 GMT -6
Oh yeah it lost a little over 260 lbs. and with the 48 volt lead acid batteries running voltage was 45-48 now it's 51-51.5 most of the time.
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Post by biggkidd on Jul 26, 2022 17:30:54 GMT -6
We just had a storm here like no other I've ever seen. the rain didn't last long but it came down in waves. Sounded just like waves hitting the bow of a boat on the roof! It was flowing in the driveway so deep and hard it was up over the tires in to the wheels of the golf cart and pushed it back a few feet with the parking brake on!
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Post by papaof2 on Jul 27, 2022 13:18:02 GMT -6
Maybe you should be converting that to an amphibious vehicle? Pontoons underneath and a trolling motor on the back ;-)
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Post by biggkidd on Aug 3, 2022 19:23:08 GMT -6
A little update on the GC. I haven't gone off property for the last week give or take. Weather wise we have had a pretty good mix of sun and clouds with rain, more cloudy days than clear IIRC. The battery appears to be about 60% tonight when I put it up after doing chores in the dark. I can certainly live with that. You have to remember I am trying to keep the battery between 20 and 80 percent charged for the longest battery life.
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Post by papaof2 on Aug 6, 2022 21:35:28 GMT -6
Looks like you're meeting your objectives ;-)
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Post by papaof2 on Aug 14, 2022 17:38:56 GMT -6
Since you monitor the cart battery with a voltmeter, here's a voltage vs. SOC chart from one of the battery makers: footprinthero.com/lifepo4-battery-voltage-charts48V LiFePO4 Battery Voltage Chart Voltage Capacity 58.4V 100% (charging) 54.4V 100% (resting) 53.6V 99% 53.2V 90% 52.8V 70% 52.4V 40% 52.0V 30% 51.6V 20% 51.2V 17% 50.0V 14% 48.0V 9% 40.0V 0% If you're using a different charge-to voltage, you can adjust the numbers. Thay also have charts and graphs for 3.2 volt cells, 12 volt batteries and 24 volt batteries (printable charts are graphics, so not postable here).
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Post by biggkidd on Aug 14, 2022 20:48:40 GMT -6
Hey thanks. My battery seems to mostly live between 52.4 and 53 I can certainly live with that. I also recently figured out I can go to the neighbors once a week and it can recover as long as there are some sunny days. I can't even begin to tell you how nice it is to have transportation you don't refuel or charge on a regular basis. It's been at least a couple weeks since my last charge.
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Post by papaof2 on Aug 15, 2022 0:05:04 GMT -6
Glad it's working out for you. Wonder how many other people you now have thinking "Maybe I should do something with that old cart?"
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Post by biggkidd on Aug 15, 2022 7:54:22 GMT -6
Glad it's working out for you. Wonder how many other people you now have thinking "Maybe I should do something with that old cart?" I hope others do set some up and use them. Handier than a pocket I'll tell ya. Speaking of did I tell ya, I have that cheap 48 volt sinewave inverter I hook to the cart battery and work from when I need power tools away from power. I keep debating just leaving it on there but there's really no reason to bounce it all over the place when I rarely need it. It is nice to have the option though!
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Post by papaof2 on Aug 15, 2022 15:34:22 GMT -6
A portable "AC outlet" is very useful ;-)
I started looking for ways to have AC power available about as soon as I got my driver's license. I even have some historical bits. - A vibrator-driven 80 watt inverter from the early 50's. - A whopping 140 watt vibrator-driven inverter with a case that held a 12 volt car battery of the time (22NF?) from 1957 - I have a digital copy of a magazine ad for it. It had a three position switch so you could bring the AC voltage up as the battery discharged - obvious in the days of CRT TVs as the picture would shrink if the AC voltage dropped. That same switch was the battery charge level when using the inverter as a charger for the battery - complete with a note to only use "High Charge" for X hours and then switch it to a lower setting.
With a little judicious tweaking of the sheet metal, I could have a 2000 watt pure sine wave inverter and a serious LiFePO4 battery pack in that case at less than half the weight of the original battery. Technology advances ;-)
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Post by biggkidd on Sept 5, 2022 19:49:42 GMT -6
July 4th the battery was been installed. Roughly 3 months and with the solar panel doing most of the regular charging duties. I checked the BMS yesterday to see how many cycles the battery has had now at a little over three months of use. 15 cycles is all in about 90 days. I think that is just way to cool. Looking like this battery may well last me the rest of my lifetime!
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Post by papaof2 on Sept 5, 2022 22:00:08 GMT -6
I have a story in progress that's partially set in the future and it mentions LTO batteries with 20,000 charge/discharge cycles being installed in devices as "lifetime" batteries because 20,000 cycles at one cycle/day works out to over 54 years. At the moment, I don't think I'd spend the extra for LTO but, at my age, LFP looks like close to lifetime ;-)
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Post by biggkidd on Oct 21, 2022 14:20:02 GMT -6
Just want to do a shout out for the 18650 battery store. Had a problem with one of the cells I bought back on May 27th called and talked to them Tuesday they asked for a screen shot of the BMS reading which I sent in the following day and they shipped out a replacement today. No hassle at all, granted they had the screen shot showing exactly what the cells were doing. www.18650batterystore.com/collections/lifepo4-prismatic-cellsYou can NOT ask for better customer service than that!
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Post by biggkidd on Oct 27, 2022 11:22:24 GMT -6
I made a pulling strap out of the cut off end of a ratchet strap by burning holes near the ends and the cells came out without to much trouble. I've got the old cells and the new cell all on the table hooked in parallel to balance them all together. I'll probably leave them like that for 24 hours.
I was surprised how much dust was inside the battery box. It has to be coming in through the fan openings when they aren't running. The fans very seldom run, I'm not even sure they are actually needed except on those 95+ degree days.
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Post by papaof2 on Oct 27, 2022 17:59:06 GMT -6
Maybe cover the fans with some furnace filter material?
If there's room, make a holder that the smallest useful filter can slide into so checking/changing the filters is easy.
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Post by biggkidd on Oct 28, 2022 18:22:22 GMT -6
Well that turned in to an all day affair. Getting the battery apart didn't go so bad using a short piece of ratchet strap to pull the cells out with. Getting them back in was another challenge, which I had to do three times. The first time I put them back in I reversed the order. The second time I suddenly had voltage leaking in to the battery box. So back out and back in again still I couldn't figure out why so I called the tech guy at 18650 and sent him pictures, he was as stumped as I was. Finally I decided to take the positive bus bar out where it passes through an insulator and the case. The problem went away. Put it back problem is back. WTH? It wasn't touching anywhere but I was getting a full 52.8 volts from the battery box. Now I'm really scratching my head asking WTH? So was their tech guy. I decided to trim out the insulator and wrap the bus bar in electrical tape, thirteen wraps later and it finally quit leaking. Only thing I can figure is steel box roughly 1 foot cube with 5kw @52 volts inside was acting like a transformer and somehow passing power. Still do not understand how or why but it's not happening anymore so...... Hopefully I can get it back in the cart tomorrow.
I also made some thin filters out of old cotton cloth and taped them in place. These are just to keep dust from falling through the fans when they aren't running.
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Post by biggkidd on Dec 19, 2022 8:15:25 GMT -6
Got down to -6c last night / this morning so I ran out to check and see if the heaters I put under the LifePO4 battery in the golf cart were performing as they should. I am very happy to report the thermostat and heater are both working as they should. The battery is at 3.2c even though the temperature is -5.5c right now.
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Post by papaof2 on Dec 19, 2022 10:38:13 GMT -6
Do the solar panels keep up with the power needed by the heaters?
I can more-or-less plan usage of the lights in the equipment shed but a farm run-about doesn't usually have that option :-(
Having a battery that won't work in the cold and only having the option of running that battery down with a heater so I can use whatever power is left when it gets warm is not an appealing design :-( We have lows of 13, 16 and 19F forecast this week but the LiFePO4 battery is not yet in the shed - too many days of needing Rx pain med to sit at the table and eat for me to spend a lot of time out on a ladder in 30F weather :-( Maybe when it warms back up to 51F ;-)
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Post by biggkidd on Dec 19, 2022 11:13:36 GMT -6
Do the solar panels keep up with the power needed by the heaters? I can more-or-less plan usage of the lights in the equipment shed but a farm run-about doesn't usually have that option :-( Having a battery that won't work in the cold and only having the option of running that battery down with a heater so I can use whatever power is left when it gets warm is not an appealing design :-( We have lows of 13, 16 and 19F forecast this week but the LiFePO4 battery is not yet in the shed - too many days of needing Rx pain med to sit at the table and eat for me to spend a lot of time out on a ladder in 30F weather :-( Maybe when it warms back up to 51F ;-) The battery has 5.2kwh IIRC the heater draws 50w when it runs. I have it set to turn on at 3c and off at 5c. So it could run a WHOLE lot of hours without causing trouble. When the sun shines the panel (300w) keeps up pretty well but we haven't had a lot of sunny days lately. I think this year I will start working on the other cart and see if I can get it going since it would use a LOT less power. This one uses the most power at the slowest speed and the least power at 100% go. The more modern type will use less power at low speeds and more at high speeds, like it should work! lol Most of my running around even the lowest speed I have now is to fast.
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Post by biggkidd on Dec 29, 2022 21:29:56 GMT -6
The battery seems not to be any worse for wear after the cold weather and wind caused the BMS to shut down. It's so seldom we get weather like that, single digits with sustained 20 to 30mph winds. I could add in two more heat pads but I'm not sure I should to be honest. I'm thinking a piece of insulation around and over the battery in conditions like that will be the way to go.
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