Good news: after 2 years of troubleshooting, my GEM is now finally running!
(But it still does not climb small hills well).
Since I last posted, my friend and mechanic has replaced much of the wiring harness, cleaned the brakes, and rebuilt the motor. (It had been sitting for so long while we tried to figure out the error 21, that it started to rust.) But today was a big step forward, as now the GEM drives along at 23 mph on flats. But unfortunately it can hardly get up the small hill just down the street, and definitely not the larger one at the entrance to our community. Lots of changes have been made to it over the last couple of years- new D&D Blue motor, new 100 Amp 72 Volt lithium Battery Pack from Ride4Fun. !(When we first got the GEM with AGM batteries and the old motor, it handled the hills just fine, but we had to start replacing components after an electrical surge) . We are now thinking we may need to check or reprogram the controller for the D&D motor and or Lithium battery parameters. Unfortunately, we are in Panama. So my questions for the brain trust are:
What equipment is required to check or reprogram the controller?
Is it something we could purchase, or do we need to send the controller all the way back to the USA? If the latter, can you recommend a dealer who is an expert in programming?
What else might cause it to have super low power up the hills? Batteries read 74
What voltage going uphill? Amps? Does it go into turtle mode?
100 amp battery or 100ah battery.
It may be that a brush is stuck after cleaning. Controller does not need reprogramming for more torque.
Throttle: Throttle can limit torque. Measure voltage on pin7 of 23p connector wot . Do not probe end of pins. Stick a needle through insulation.
Battery: Battery may be low voltage. What is voltage hot off the charger? 84volts or so? Prefered.
Brakes: Check them again. Does car roll easily when pushed on level ground.
When did your friend rebuild that motor? If it has been a while, it may need another look (the motors HATE sitting).
Also verify that you have the speed select switch in DH position, and there is not a temperature light visible on your dash display. Both of these conditions will limit the power.
Batteries read 74
I believe the R4F battery is considered a stock voltage level battery and not considered a high performance/voltage battery. Your reading of 74v seems real low.
When/what conditions did you take that reading?
Have you tried contacting R4F about this?
I found it odd to see the Nominal battery voltage below the Min Charge Voltage on the case of this R4F 105Ah Lithium battery pack but probably some kind of BMS charge range setup.
A 24 cell LFP battery at 74V is 3.0V or about 10% SOC so not much ‘in the tank’.
I’m not sure I understand what you mean by
“I found it odd to see the Nominal battery voltage below the Min Charge Voltage on the case of this R4F 105Ah Lithium battery pack”
I’m not familiar with seeing a “min charge voltage”, can you explain it?
On the GEMs I’ve seen there is a very low battery voltage under which the battery charger will not work if below that voltage. Would love to hear what that Max and Min charge voltage values on your battery mean.
I wasn’t asking anything. Your stated battery voltage of 74V indicated your battery was effectively empty of charge.
Try fully charging the battery, measuring the battery voltage after letting it sit for 30 minutes after the charging stoped. Report the fully charged battery voltage here.
You never provided a link to your 100A R4F lithium battery so I googled and found this 105Ah R4F lithium battery and hoped it was similar enough to show what the voltages shoud be.
But I will repeat the question regarding your stating you had performance issues with 74 volts on your 72V R4F lithium battery, WHAT IS THE MEASURED BATTERY VOLTAGE, of your battery, WHEN FULLY CHARGED?
And you can always put the user name in your comments like this - @Pythan
It wasn’t my battery issue. I was only commenting on what I saw as "I’m not sure I understand what you mean by
“I found it odd to see the Nominal battery voltage below the Min Charge Voltage on the case of this R4F 105Ah Lithium battery pack”
Is that picture not of the R4F battery?
Nom V= 76.8VDC Charge V Min 79.2VDC
I was actually inquiring from you, what you meant? it was just a general battery question about what you found as odd.. It was for my general knowledge only..
I have no battery issues myself..
@dougl@Pythan
Doug meet Craig. Craig meet Doug.
Doug is the cranky retired college electronic professor
Craig was in a musical group, 'The California Rasins" he was the golden rasin. No one can belt out Marvin Gaye lyrics like Craig.he did suxh a good job, the label got scared and fired him and then erased him the videods. After that he went into electronics, control automation.
Craig is the guy with the train. Its sofaking cool. I actually got an up close look at it got to ride it when i went up there and reprogrammed the controlee.
Doig is the guy that after his retirement from UCSD, he took.up a part time career, with flexibility. Only works 1 l month a year. He goes to sopping malls in december and scares the children in line fir santa He even gets to dress up like Klakkmus. Even got in free to a Black sabbath cconcert by showing up in cosrumr.
