If the 90’s honda wheels fit the GEM, makes me wonder if the same honda disc brakes and calipers could be adapted to fit as well. You can pick those parts up a lot cheaper than the GEM disc brake conversion parts…
That’s would be a nice upgrade and last longer I’m sure. Worth looking into
That looks really clean man I need to find time once I get all my little bugs fixed and install my BMS. Looks great, daves wire harness Are nice. How many volts and amp hours is that set up?
Thanks. I’m retired - got nothing but time.
21s pack set to charge to 4.1v per cell, about 86v for pack, 95% SOC.
I think they rated for 47ah, much more than I need for my short trips.
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don’t worry too much about over reving motor . I’ve been running my old 02’ 5hp stock motor at 38mph on lithium for 2 years now and haven’t had a problem .
i’m no expert at these shunt motors but my understanding is they well only rev so fast and they stop.
personally I haven’t heard of anyone over reving and blowing a motor .
p.s. I have larger wheels the yours and have taken the stock 5hp over 42 mph multiple times.
Info is much appreciated, now I won’t watch my speed as closely. Even if I don’t blow it up, motors days are numbered due corrosion on the case. I’ve slowed it’s spread but it is still growing, probably on the inside too. I’ll go to a higher revving motor, maybe D & D, when it dies.
I closely followed your conversion while deciding if I wanted to try it. Great info, thanks.
Rodney is the only one warning against over speed. Well, I guess I am too!
He also has the most experience.
If anyone has first hand knowledge of a motor grenading, post it.
I have not.
I’ll ask him for another look at it.
Three month update.
Lithium batteries have been great. Initially saw about a 100mv to 200mv high to low cell difference after a heavy discharge. After about a dozen charge/discharge cycles the cells have settled into a 20-60mv diff. Wife and I completed a 13 mile run recently at mostly 30 mph. Pack volts started at 85v, I only charge to 4.10v per cell and car sat for over a day after charging. At the end of the run pack was at 77.5v.
Delta Q charger was a problem. When weather warmed it kept charging, even past the max charge setting of the lithium profile that had been installed. Initially thought the BMS wasn’t sending the off signal but that wasn’t it. The DQ was charging at 20+% higher than its rating. Not a problem for the batteries but causes the charger to make more heat. Since it is flush mounted in a boxed in area under the controller it wasn’t getting enough air flow and was going into thermal overload protection mode. This was indicated by a flashing AC power light on the DQ. When in thermal OL it just kept on charging, even though BMS sent the off signal and would continue past the profile setpoint. It was locked in the ON position. Only way to kill it was to unplug AC power.
I lowered the back end of the charger as much as I could, about 1/2", without hitting the steering column and dropped the front about 2". This allowed more air flow all around the unit and it hasn’t been a,problem since.
After many consults with David, I added a solid state relay to the AC power cord for the charger. The BMS now turns off the relay to kill power to the charger. This is a backup in case the charger keeps on bookin’.
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Very interesting charger problem. It must be a design flaw that lets it fail wide open.
I’m glad you found a work around.
For most 20M max won’t be enough.
I’ve been doubling up on my own.
If anyone else is interested in Volt conversion, I have one 5kw - 24s module left from a new (almost) 2016.
The rest of the pack is in my EL and Tomberlin.
Either alone or with charger/bms.
Fitment is an issue, and it’s a shame to split the pack.
An EL would be perfect.
its normal for a dq charger to do that if you use a lead setting with lithium . the lithium has low internal resistance , when you hook up a dq charger the charger cant regulate its self properly and puts out too many amps . then it goes into thermal protection and slows its charging rate down , but it gets hot .
this is one of the things that changes when you put the lithium profiles into a dq charger . sounds like you found a fix for it
He has the lithium profiles.
Rather than shutting down on high temp., it ran wide open. Even when white enable wire was disconnected.