I just got back from a government surplus pickup of two carts. 2015 el xd and a 2010 e4. I am diving into these without much background on EVs. Feast your eyes on these 2015 factory install batteries haha. Any decent recommendations on 72v lithium for less than $1,800 (Amazon ones)?
Also, I would likely want to bump the speed on the 2015 el xd. I’m assuming Magic magnet. Any other recommendations? I believe these carts sat somewhere with no water. Super Dusty… hoping it’s just bad batteries.
A 2010 with an external DC-DC? That’s odd. Early (month) release or modified? IIRC in 2010 they switched to DQ chargers that had internal DC-DC converters and eliminated the SurePower DC-DC converter. Just for curiousity, can you make out the part number stickers on the charger, they will be on the feet/rails where the screws are that hold it in place, you can see them when you look down, or up in this case at it, since its mounted upside down.
As for hot rodding them… You stated you would like to make the 2015 eL XD faster. How muich faster? And, what are your plans for the 2010 e4?
FWIW… The eL XD is the proverbial F-450 of the line: eL: XD = electric Longback eXtra Dorky, errr… Duty e4 = electric 4-passenger.
The eL XD has a higher payload capacity than other GEMs, on par with the e6, except meant for cargo rather than extra passengers. They have more powerful motors - both in hp and torque, lower / shorter gear ratio differential - more torque but less wheel speed, and when empty on a rough road the eL XD may just try to shove your kidneys up into your collarbones.
For both of them, I would recommend getting clear photos of the:
nameplate on the motors
nameplate on the controllers - the gray box on the platform above the motor / charger
any stickers found on the differentials
model number on the chargers - these will be white stickers on the feet/rails that it uses for mounting - they face “up” but the chargers are installed upside down…
Tire sizes.
DC motor Gems love higher voltage, Easiest way to make them go fast, is to increase the pack voltage, which increases voltage to the motors. An additional 12V will get you a lot. More than that will get you challenges, headaches and maybe even some magic blue smoke.
Forget the Amazon lithium batteries if you are looking for performance… from the ones I’ve worked on and stats on others, they all seem to be primarily geared towards the golf-cart market. Not performance, but rather convenience oriented and low risk. This goes for both the group 31 (or whatever) sized batteries and the all-in-one drop in boxes. Full charge for the ones intended for 72-volt carts is typically is around 76v, this is basically the same voltage output as you would get from six fully charged 12V batteries or nine 8V.
@inwo can take good care of you on the lithium pack and magic magnet to trick the speed governor.
Some free words of advice, if you haven’t run away screaming yet:
Don’t tear into too many systems at once or too quickly on these. The electronics can bite you in the ass. Keep one assembled, that way you have a cheat sheet… Very easy to get yourself into trouble or regrets, both money and work / time.
Ask if you are unsure. Motors in particular. Not hard to work on, but easy to fark them up, even just disconnecting the power leads. If these had typical fleet maintenance and sat in a wet junkyard like most government surplus seems to, they might not come off easy when you get to that. Don’t force them off. They only have one support bearing, it’s at the tail end, the shaft end is open frame and no internal supports.
Be careful with the brake parts, especially the calipers. Some are made from unobtanium.
nev-accessories .com, good guys, good parts source for mechanicals.
If these sat in humid or wet environment, electrical connectors will be the bane of your existence, CAIG DeoxIT, some brass brushes (never use sandpaper) and the Lego guy will be your best friends…
Headlights are junk, first time out at night you’ll wonder how they built an all electric with such crappy lighting. Don’t waste money on bulbs, be it halogen or LED inserts. Best bet is to eventually swap them out for sealed off-road LED lamps. Built in high-beam is a dammed joke. With LED, you can do stupid lighting tricks like use low-beam setting to run headlights and high-beam to turn on headlights and a light bar - if you do it right, you may even succeed in forcing opposite traffic off the road by thinking you are driving a Tesla with a broken auto dimmer, or you are a low flying DC-10 on final approach.
Rims / wheels everyone hates the stock ones. Leave these to last… On these vehicles, they play into your top speed and torque, a lot. Also, wide big sidewall off-road-ish tires look cool, but can cause steering drift - make you look like you’ve had a six pack too many trying to drive a straight line.
PS: AssyRequired did not ghost write this post for me. Crap that’s long… Sorry.
I’m Likely only going to mod the 2015 xd. I’m going to use it to travel to the municipality golf course to do our cleanup efforts for the nonprofit. So, I really only need it to hit 35 mph. Do you think the 200a BMS sold on Amazon would be able to achieve that without needing a reset? Honestly I don’t need to go any faster. Plus I need some torque for hauling trash and debris.
I am pretty handy but I never worked with vehicle electrical before. So, I’m not sure if I have what it takes to guarantee a 100% no issue install of a custom battery.
This response is from someone who truly cares for this craft and I really appreciate the effort that went into this!
I believe it was 3/2010 manufactured.
I’m likely looking into modding the xd only at this time. But I wanted to upload all of the information from both carts if a parts swap made sense. Also, it’s dorky now…. But.. I plan on upgrading her to look xtra Dope! See photo of vision lol.
I have also added the photos of the equipment from different angles. Second also, I think they were stored in army bunkers underground. Hoping no other issues. I don’t exactly have 6 12vs laying around at this time to test them out.
Again, I really appreciate the support and knowledge you all bring to the table on this!
Your 2010 e4 has a “long GE 5hp” motor and the diff ratio is 12.44:1. For that year & motor / diff combo it should have shipped with a T4 controller.
The 2015 eLXD has an “AMD Black 7.5hp” (fan cooled) and the stock diff for the eLXD and e6 had a ratio of 14.75:1 Would have shipped with a T5 controller.
Both were good setups from GEM / Polaris.
The long GE5 is a good, reliable motor for average daily use. Can take some mild abuse too. With 88v, an MM, and slightly taller tires / rims it’ll get that e4 up to 35 easy.
The AMD black motor is a beast. One of the more powerful stock DC motors they ever shipped. Bad news, it has very tight tolerances, and some might say it’s temperamental or finicky. If it’s been sitting in a damp bunker for a while, it’s going to need some TLC service.
Not sure what you mean by
BMS = Battery Management System.
It’s just a semi-smart hardware device that monitors and tries to keep all your cells at the same level and maybe help you not melt or blow stuff up. It attaches to the individual cells in the battery pack and power in & out of the battery goes through it. It can be used to adjust your full charge voltage and max load, but its not a battery.
It looks like you have a good start on a couple of projects.
Govt surplus can be a great source, but getting enough of the legal paperwork, title, and plates can be tough (depending on what state you are in). If there are plans to drive them on the street, try and get that squared away first.
– I look at new rollers sitting in the driveway and find out what they want to be and how they are going to work for me.
– Come up with a build plan.
– How are these cars going to be used?
– How much speed and range do you need?
– What terrain are they going to be used in?
Also important:
– What is your skill set?
– What is in your tool box?
– How big is the budget?
– What is your timeline?
Battery Pack Thoughts
Be very careful of what you are looking at on AmZon. Most of those are probably ok for golf carts, but a Gem car falls into a special range of battery specs that most builders are not aware of. It takes a lot of work designing a battery to properly power a Gem car.
The battery you used in your example [above] –>SiSway 73.6V (72V) 105Ah Golf Cart Lithium Battery ←
may seem like a good deal, but will be on the very low end of the target voltage range. I’m guessing this example might be a 21s pack or maybe even a 22s?. It will drive around like you are running a very tired old set of LA (lead acid) batteries constantly in need of charge. Your range will not be very good either. People will drive around you yelling at someone called grampa and telling him to get out of the road. Your dog won’t want to ride with you either.
You need to at least target a volt spec up in the mid 80’s. If you can get the build specs it will have 24 LiFePo4 cells. Depending on how they are rating it, they will show 80 to 85v. Higher the better.
Next level
For a real hot rod car, you will be looking at a special battery build (what Inwo was suggesting) and be up in the sweet spot up around 90v. Many here have found out that these cars respond very well to higher voltages and very fun to drive.
Appears to be the same as, possibly identical to, the Elefast 73.6V (72V) pack which I have worked with. From what I experienced, I would say it’s optimized for golf carts. The GEM has much greater loads, power needs & consumption and performance demands than golf carts. That battery system uses a 23-cell LFP4 pack and tops out around 83 volts IIRC. The BMS settings are locked from the manufacturer, there is basically nothing you can control or change.
In fact, check the below linked thread out… actually, belay that, just skip to about post 85. Cliff notes: the OP has an e6, which is the same as an eLXD, they are just set up for 6 passengers rather than cargo. His is modified a bit, it’s on the heavier end, but not much different than your eLXD would be with junk in the bed. He has the same battery you are looking at - and it barely gets to 20 mph and it struggles to go up inclines. That does not seem to jive with what you seem to be looking for.
You don’t want that $1800 Amazon pack. For that kind of underwhelming performance you might as well wait for the 20% coupon sale at O’Reilly Auto and pick up six 31DCM or 31DCMJ group 31 marine 120Ah batteries for $110 each and use the $1000+ you saved to buy something really, really nice for whomever you had to convince that buying this now uber-slug of a GEM was going to be cool, fun and fast…
Being totally honest with you here man…
If you like the load capacity and torque an eLXD has to offer, and you would like to retain that and would like to see 35 mph top end while not sacrificing it’s already slower acceleration further, and your vision of it’s future form which appears to have something like 25" diameter tires… a high voltage battery that can also provide high current on demand, for real, is a good place to start. It will get you a lot closer than anything on Amazon and most other ones being offered up out there.
Neat thing about @Inwo and a battery from him, is that he actually knows GEMs, electricity, motors & batteries and works with others who do too. I’m one of those recovering diverse engineering types, and I wouldn’t have bought two GEMs, multiple batteries and other nifty stuff from over the years if the engineering math didn’t support or I didn’t think he knew what he was doing.
So, here’s one to think about. I don’t recall ever seeing one done up like this.
Three words: Crew Cab Longbed. Keep the rear wheels where they belong on these, at the end. Want to go full redneck with $$$ … steal the rear axle assembly from the e4, stuff it just in front of the eLXD axle.
You have an eLXD frame and hopefully all the running gear works. You also have an e4…
All you need is someone who can fab a bit and TIG weld heavy wall extruded aluminum frames… Correctly.. Straight with reinforcing so it doesn’t sag or crab walk…
Yeah, it’ll be heavy, slow, turn like crap, but… 'Merika, Fvck Yea!
Reason low voltage lithium won’t work well. Car will turtle, then die if battery dips under 68v. If your battery is still 1/2 full, you have no way to utilize the bottom 1/2. You want a battery that doesn’t go under 70v, 72v even better. 80v car will feel like it’s hot off the charger.
I really do find this information super interesting. I was a C-17 Crew Chief for sometime in the military. So I like to learn and work with my hands. Your (along with JarJars)wisdom has steered me clear of the Amazon lithium path.
If I was to get a battery from you, or anyone else online, I believe I would need to first test out the system. So, I plan to buy 6 new semi cheap 12vs and try the systems to ensure they work. Then if all seems good, I would likely reach out to discuss options on a prebuilt battery setup from you. I could use the 12vs on the cart I don’t plan to “hot rod”.
Just curious, do you know who can reprogram the charger I have, when I go to lithium? Who would I reach out to in regard to the magic magnet? Any warranty on a battery pack purchased from you?
As much as I would love to spend that money on someone as professional as yourself, or anyone with this knowledge base, I sadly cannot lol. I have already had to donate all my personal collections to the nonprofit to sell to pay for the mission . However I will definitely take this information and hopefully get a good deal at a battery warehouse.
Just to test or “wake up” a car to check for blown up stuff, I have had this thought in the back of my brain for a while now.
Normally I don’t suggest this “mad scientist” sort of thing without first trying it myself, but since you have a need at the moment, I suggest it for you to use.
What do you have around for power packs? Some of the new leaf blowers have batteries up around 80v. You could even tie two 40v together (if that is what you had. Get your math correct and you could even use a couple tubes of D cell flashlight batteries. It won’t be enough to actually move the car, but it would surely wake it up enough to check basic functions.
. However I will definitely take this information and hopefully get a good deal at a battery warehouse.
