Comment…“I find it odd that most of the cart world is just now ramping up with their Drop-In multi battery kits and it will be interesting to see what happens with all of that especially with their 10 year warranties”
Me) What is odd about your above statement?
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Comment…“It looks like the charger you pictured in your post(DQDB) is one that can be programmed for different profiles and higher voltages.”
Me) I attempted a google search for DQDB charger and almost nothing came up.
I did see some where a $100-80 kit for programming. I dint have tome to look into what it was for or what it could do.
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Comment…“Note that much of the battery tech has been found to be problematic here and tends to be worn out in about a year. I don’t think anyone here is still running Lifepo4 and has moved on to other things with more promise.”
Me) Why would prismatic cells be worn out in a year? Are they being charged by a none lithium compatible charger?
I have already spent thousands on different kinds of Lithium batteries. I am not going to go out and spend $3000 on a set of lithium batteries until i learn why prismatic cells are failing in a year.
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Comment… “.IMO- Your Gen1 Leaf cells at 66% may not be worth the effort. It is up to you.”
Me) What would be the downfall to using the 66% leaf cells? I dont need to go 25 mph. and i dont need to travel 22 miles. I paid $500 dollars for the 2012 leaf that had a 33 mile range. What can i expect from 10 Leaf cells At 66%. I can always put in 20 cells. 10s 2p.
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Comment…“The Rivian modules sound like an interesting choice but I don’t know anything about them. The guys here smarter than me figured out that the classic gems really enjoy running higher voltage. 88 to 90v is a great upgrade”
Me) I have been told by someone in the Gem forum to not go above 86 v.
The Rivian modules are 17x24x8 15kwh each. 150 lbs each. Nominal 44v,12s x i think 7p
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Comment…“Decide on a build plan for your car. What is your car going to be? What environment will it be living in?”
Me) My goal 6 months ago was to buy, build, or modify something into the smoothest riding golf cart possible.
Possibly AWD with a second electric motor for the rear, lifted a little with long travel suspension. Biggest widest tire on the smallest wheel possible that will fit. If I need to modify the fenders, so be it. Tall sidewalls are to smooth out the ride with aired down tires. I was even thinking of possibly building my own tube frame. And put on some VW bug/ Beatle body panels.
Air suspension seats and air suspension shocks.
I will very rarely if ever carry 3 passengers. So the rear floor and under the front seats is a possible option for batteries.
My unit does not have heat which I definitely want to add. Living in Minnesota you go golfing any time the courses are open.
AC would be a plus . But most likely will be a container of ice with some duct-work blowing cool air on our faces.
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Comment…“You will also need to learn more about what you have.”
Me) 2015 e4 Gem. Flood damage Copart insurance auction from Florida. It has sat for a year just north of Minneapolis. All 6 batteries were cracked open due to freezing. Polaris batteries. No title, certificate of destruction. There was a water line drawn about 6 inches up the front seat bench. The cart appears to have nearly 1000 miles on it. The under side of the carts aluminum frame did have a white chalky substance that did taste salty.
before purchasing i found instruction on how to apply voltage directly to the motor, bypassing the controller. The owner briefly but 12v to it and the wheels did slightly turn. He immediately removed the power. The owner had charged the 12v batteries individually the day before and said he did get the screen to light up. But the screen went blank as soon as pressing the accelerator. The rear brake drums did have some white deposits. I don’t know if the motor was submerged. They were giving the cart a power wash when i arrived.
Tires look very good.
No doors.
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Comment…What motor is in this car?
Me) I will add pictures.
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Comment…What gear set is in the gearbox?
Me) I will add pictures.
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Comment…What is your skill set?
Me) 60 years old. Went to trade school for 2 years for HVAC . Installed furnaces and air conditioners for a year. Then building maintenance for 3 years. Then a stay at home Dad for 13 years. Purchased many $500 dollar cars and fixed them up and drove them for a couple of years before selling for a $1500 profit . I have only owned one new car.
The others have been 10 years old or older. In 44 years of owning cars. I have only brought them to a mechanic 3 times. The first time I was 18 and my 1987 Plymouth Horizon died on the way home from very religious private party. This was long before the internet and paid $600 for a ECM. My second car going to a mechanic was a Nissan Stanza Wagon. On the way back from South Carolina during the Minnesota Great Halloween Blizzard of 1991. My alternator died in Wisconsin . My car cranked real slow after a gas stop in Wisconsin. The temps had dropped to Zero F for highs and the highways were covered with 6 inches of ice. 36 inches of snow had fallen over three days. I purchased a new battery there , not knowing the alternator was dead. The battery got me to within 10 miles of home when the radio quit working. I quickly turned of the blower fan off. A few miles after that the car started sputtering, Luckily right at an exit ramp. It died Half way up the ramp with a garage at the top. I took the battery out and they charged it and we drove home 
I had no garage and the book said it was a 5 hour job.
The third was a 1995 Subaru outback that I also had picked up after a crash . The Ticking sound turned out to be the flex plate. It had literally cracked all the way around. then shifted and jammed itself in place with an edge sticking out that was ticking something. I had a garage put in a new flex plate.
I took the roof off of my house and put in floor trusses for a floor . Then hired a framer to put up the walls and rafters and all sheathing. After that i finished the rest. Electrical, plumbing sheet-rock trim windows roofing siding I also built a detached garage with only the help of a guy who pumped in concrete from the street.
My one new car had its transmission fail at 135,000 miles. A 2001 Honda transmission. With one very good YouTube video i rebuilt the tranny. After 60,000 miles it is still going strong.
Its been years but i have painted a couple of cars. I have built a couple of desk top computers.
I grew up helping my dad fix our hand-me down cars from his siblings.
My memory/recall from reading and spelling has sucked since grade school.
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Comment…What is in your tool box?
Me) Nothing fancy
But enough to get car repairs done. This includes a 60 year old oxyacetylene torch and a Lincoln 125 wire feed welder. Not skilled with them. But functional…
I have been watching way too many YouTube videos on electric cars and electric conversions the last 4 years.
My license plate is GOLFISH I am either golfing or fishing with my brother. We have been doing BWCAW canoe fishing trips for 40 years. (Boundary Waters Canoe Area Wilderness). Or crossing the boarder into Canada’s Quetico Park.
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Comment…"Here is where it gets tricky when designing your own pack. This is why I suggested you to study up before you jump in on a project like this.
20 is not going to be enough.
Also- are you running a BMS?"
Me) Right now i am just trying to get the wheels to turn. And figure out what works and what doesn’t. After that i will work out the other details.
When you say something like “ 20 is not going to be enough” You need to add why it is not going to be enough. Especially to a newbie.
Otherwise you just raise more questions. Like, will I loose range? Will I lose acceleration? At what pack voltage will it quit all together.
My wife is exceptionally smart. Too many times when I ask a question. She will answer the question she thinks I should have asked. And never answers the question I asked without prompting. And that happens often on online forums. The responders are well meaning and knowledgeable . But don’t actually answer the questions asked . And answer with information that is obviously beyond the specific knowledge of the person asking the question. Like” some are enjoying the benefits of running at 88-90 volts or higher” . But don’t bother to say how to obtain this voltage.
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Comment…Are there any codes on your display now?
Me) I have not seen any error codes. I included earlier, three pics of the screen. When I first got the screen on with the 66v . There was a wrench on the display. That disappeared after getting 76v
The three pics where taken after getting 76v then hitting the trip button 3 times. I don’t know what the “E” is for on one of the pics of the screen.
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Comment… “What do you mean by this?
The tail light harness?
Maybe the headlight harness?
Those won’t keep the car from going.
Anything else disconnected?”
Me) For ease of seeing everything and removing the batteries. I removed the rear cover and disconnected the wire harness leading to the back behind the cab.
I also remove the front cover assembly. And disconnected the wires leading to the headlights and anything else that required separating to remove the cover.
The top dash and lower kick panel is also removed. The only thing disconnected there were two wires going to the 12v power outlet and two wires leading to the red flasher button…………………………………………
Comment… “18-19s battery will error on low voltage unless over charged.
22s + will error on high voltage unless under charged.
21 is the sweet spot. Get by with 20s.”
Me) What is the voltage that will trigger a high voltage error ? And what voltage will trigger a low voltage error?
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Comment… “I might be confused on what cells he is using.
I thought it was LFP, (maybe an Eve cell).)
Me) I have not decided which batteries I will settle on. Right now I just need to figure out if I can get it to move.
I have a 2017 complete crashed/totaled Leaf with I think a 30kwh pack with 48k miles. I have not put leaf spy on it yet to run a state of health.
I have complete and running 2012 leaf with a 24kwh 66% soh with a 33 mile range that I paid $500.
I have a 24kwh replacement leaf pack that was used for 1 year.
I have nine 15kwh Rivian modules at 44v nominal 24x17x8 150lbs
Why so many batteries ? ? ?
I want to convert a 4x4 to electric to plow snow. . I want to convert a Subaru Baha . a 40hp outboard, and maybe a 90hp Mercury outboard jet motor. And put lithium batteries in a GEM.
And maybe inbed the 9 Rivian modules into a trailer. And use it for camping or just extending range. And use it for charging other evs
Converting a modern gas car gets extremely complicated if you want to keep ABS and airbags and traction control working. All safety features I require. Plus I want the range to make it a capable vehicle and not just a show piece.
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Comment… “Timf1981 - The cells have been sitting in my basement for a couple of years. And are down to 3.3
Hopefully that is not a Samsung cell. It needs a charge”
Me) yes, all my batteries need to be charge to be put in use. I currently am not set up to do any charging. But I am not planning on putting anything under load until I get everything working and in place.
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Comment… “Have you tried dropping the hand brake(verify that the brake light on the dash goes out”
Me) The “brake light” is that in the center of the lower dash near the power outlet? I was thinking that was a hazard flasher button. That circuit will be the first thing I insect when I get a chance to get back at it.
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Comment… “If using lfp cells, 24s is minimum.”
Me) What is the peak voltage that you recommend charging LFP batteries to?
What is the max voltage a stock 72v gem handle?
What is the minimum voltage you want to run a LFP cell?
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Comment… “I looked briefly through some electrical diagrams.
Actually, the electrical system is quite complex and it takes more than a quick look to fully comprehend and appreciate everything it does and why.
I have been trying to guide you through the diagnostic steps, but you seem to miss half of what I have been suggesting. This is not a direct path to success. You might get lucky. I hear the monkeys are still working on the complete works of Shakespeare too.
Or- You can blindly poke around at a few things, and possibly do damage to some critical (expensive) components.
Your call.”
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Me) Other than suggesting to drop the manual brake handle. I still don’t see any other “diagnostic suggestions” offered.
I was at my nephews house helping him fix his 2003 suv. I picked up an ecm at a junkyard, then pulled a mosfit out of it and soldered it in place of the burned mosfit in my nephews ecm.
The suv still would not accept the idle air control relearn procedure from my Autel scanner and wouldn’t take a manual reset either. Over a couple of days of trying different reset procedure and adjusting the tps to 0.44 volts. The car ran great for one day . Then it reverted back to its surging and high idle.
It was during a lunch brake I downloaded the service manual onto my phone Then scrolled through the electrical diagrams and took screen shot of the diagrams showing the contactor feeding power to the controller.
I am not bad with a multi meter. I am not a monkey sticking a long screw driver in there and shaking it around.
I knew enough to realize I really didn’t have a full connection from the battery to the controller. The pre charge circuit is mentioned quite often in the ev conversion videos. I had never worked on anything with It or seen it in a schematic.
I did resist putting 72 volts to the coil of the contactor that supplies power to the controller until I learned all the safety features that need to be in place are satisfied to send power to the coil.
This circuit is the only thing I need to focus on right now.
When I get it to close.
It will allow me to see if the controller and motor are in true working order.
Next would be the charger.
Is it working? What is its full function?
How to change it to a Lithium battery charger. And possibly run everything on a higher voltage.
I don’t need more speed and probably not range. But it will help me decide which batteries I want to use.
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I think this covers every question and comment in this thread.
I hope this helps.
Thanks…
