Thanks for taking the time to reply to my issue. It’s coming in the shop for the fall/winter as we live on the rainy side of Washington State. I will put some time into your suggestions this year and see if that helps. Here at home we’re fairly flat but where we keep it for the summer, we do have hills, steep hills. 2 adults and 3 grand-kids, it has issues. Not as many before with the 3.5 HP original motor. All new Trojan batteries and of course, totally charged. Check for hot cables etc, not the issue. Give it a few seconds to a minute or two we’re back going again. What a pain.
The car came out of Seaside Oregon as a everyday rental. It does have some rust issues. The contact points could be the issue as that’s a new one that I haven’t heard of.
Thermal heat sink paste manufacture you recommend?
It sounds like more than just a heat paste issue, but you might want to look into installing a finned heat sink and fan under the controller. The industrial carts had these installed from factory. You might find one used but if you have any fab skills you could order the materials and fit one.
Too many of the -41 codes and you might run into permanent controller failures.
Do a quick search in the forum archives to see if the 7th battery mod and see if this is for you. Since you just invested in a new bank of batteries this will give you a taste of the overvolt advantage. The extra volts will probably help getting you up and over the hills and get you a little more range back now that you are using up more amps.
The next step is going to Lithium but that is another topic.
Cart is from Oregon, now in Washington, and has known rust issues…
Check for dragging brakes. Jack the cart up and soon reach wheel by hand see if any drag. Then check and clean all your brake hardware. It doesn’t take much of a drag to bog down a gem.
Or you controller could be on the way out. Anytime it throws errors about itself, be suspicious.
Any idea what a normal temperature would be for front drum brakes would be? I was working with a friend’s car this weekend and hitting the brakes with a heat gun. Both front brakes were around 240 degrees after heavy braking with 2 adults downhill. The temps were consistent between the front 2 and rear 2. Front were hotter than the rear.
I guess now that I think about it… we probably should have found a long flat run and then hit it with the heat gun after vs. with heavy braking.
Dave,
Got to ride in Erniea15 Gem tonight! what a great set up. he mentioned you did the battery motor controller and charger system that worked amazingly on hills especially. After ridding in his Gem I am going to order a new 2021 and then plan to do the Battery swap to Tesla and controller/Motor depending on what you recommend. All I need is 35 MPH and good hill climbing so if I get the larger factory motor have you mastered a controller for it yet or should I just get the small motor being I will need to upgrade to the motor with the controller?
Would you be willing to build another battery pack like the one you built Erniea15?
Kevin
My config (once I square away my throttle issue) will definitely meet your requirements of ripping up your hill… and you could probably do it 10 or 20 times on a charge!
I guess the question is if you got the upgraded motor + @Inwo s6 controller + bigger lithium battery, would that work? or do you need to swap out gears.
Sorry, the Tesla batteries were one off. I did it for the challenge and to use the batteries I had.
Nothing special about the Tesla except the capacity. I can build something when you need it.
If it was now, I would suggest two of the 22s Samsung sdl batteries that Michael and I sell.
There is a chance that the 6.5 motor will work without a complete redo. Time permitting, I can test on my 2018 6.5 kw car.
Actually a very good chance it will do what you need, by changing battery and controller only.
Oem electronics will function to 60 volts. Then you keep your motor, dc-dc, and charger.
If I can’t get that setup tested in time, you need to recruit someone near you to help out.
Ernie or Grant maybe.
I’ve got a slight backlog of projects but am more than willing to help out.
@KevinUpHills any idea how long it takes to order a new GEM? Sounds like you could be good going with the factory 6.5 motor, controller swap, and bigger battery. Nice thing there is your speed will still work I believe.
No speedometer. Virtually the same are what you have done.
Except will use original gears, motor, charger, and converter.
Not confident that it will have enough power, after seeing yours. Power will be similar to stock.
Lighter weight higher voltage battery may or may not do it for him.
Will reach 35mph and still be geared 17:1. I’m optimistic that will handle hills, but it will not scoot up them at full speed.
With 48v lead I’m seeing 20mph up hill. It looks like I’ll be forced to swap batteries if I want to recommend this short cut.
Kevin’s also talking about modifying the bucket seats to bench seats so he could roll 6 deep if he wanted to. We only met for 45 min but he seemed like an “all-in” kind of guy. Do it and do it right! What say you @KevinUpHills
You guys are great I just finished my build sheet with my guy at Gem this morning. He says car will be here in 108 days or so.
Quick question from my friend who designs electric car for a living is on the 80v battery pack powering at 48V motor are the motors not burning up prematurely or are you reducing the voltage to the motor from the battery?
Ok great news bought Gem e4 that was on showroom floor so I pick it up next week. It has the 6.5kw motor. My friend who builds lithium battery packs wants to build a 4 pack system like Ernie’s car. Can you help with a controller that will work with that battery system?
These are the batteries, he is going to set it up 2 batteries in parallel and then add second set of 2 to make a system that operates from 48-57v so it technically could be a plug and play system with standard controller but that won’t get me above 25 which I want
That should work for a 48v system. I suggest you do some testing with the new controller before committing to the 14s batteries.
It may not give you the performance wanted. See if you get the required speed uphill with the stock car before making any changes.
All the new Gems are pretty mild. It will be interesting to see how it works for you.
As you know, there is a total of one Gem running 48v with a generic controller. afaik
Would you be interested in flying in to take it for a ride? Giving your critique on it. It’s been so long since driving it stock, that I don’t know myself, how it compares.
Getting ready fir my new Gem car to arrive this week so if your still interested I will be selling my 2002 now. I am in Southern California not sure how far away you are?
Kevin
