How to increase a Gem's range

GEM Forum
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One of the top questions I get asked is how to increase a Gem’s range . So I want to share a few ways to do it . Some are easy and cheap , some not .

  1. Increase the tire pressure . Most Gems I get in the tire pressure is low . Increasing it to 35psi will increase range and top speed . I did a test on flat ground . Gem had 21psi in the tires , increased it to 35 psi and picked up 2 mph .

  2. Keep your speed down , This is No fun but Gem’s are like cars . The faster you drive the lower your MPG or in this case , MIles per Kilowatt ?

  3. Increase it’s regenerative braking . Regenerative braking takes your speed and converts back into energy and puts it in your battery . Without it you are taking all that energy and wasting it on braking .Tesla’s have a lot of this programmed in and they call it one foot driving. Once you have it you don’t want to be without it . Gem has it but from the factory it is set on low . Also for you pre 2005 guys with crappy drum brakes , This will help slow you down and probably eliminate the need for a disc brake upgrade .

  4. When programming a controller keep #7 as high as possible . Reducing field current (#7) will increase a shunt motors top rpm . For those looking for more top speed you want to do this but it takes more amps from your battery . If you have all the top speed you need , Especially the lithium guys don’t reduce this number . On my personal gem I increased it . Because my Gem has high voltage lithium the top speed is more than i need so no reason to reduce #7 . If you drive your Gem and it surges at top speed your #7 is too low.

  5. Increase battery voltage . Raising your pack voltage increases speed and range . You can do the 7th battery hack for lead or add additional cells for lithium . If you have a 25s lithium pack increasing it to 26 , 27 or 28s will increase range . Don’t forget to increase the chargers voltage to compensate .

  6. Replace your batteries with higher amp hour ones . Lead and lithium come in higher capacities so when you put in new batteries put in bigger ones . The DeltaQ charger can handle them .

  7. Get the lead out ! The number one thing you can do to a Gem is lithium . It will make it faster ( with a stock motor 40mph is possible ) It will go farther , Mine is probably 50+ miles . And it will get much lighter . A stock pack with hardware weighs about 425 lbs . A lithium pack 85 to 150 lbs . A stock E4 weighs about 1200 lbs. Take out 300 lbs and you have removed 25% of its weight . That in itself makes it accelerate faster , handle better and stop much quicker . Add it with all the other benefits of lithium and it is the best thing you can do to a Gem .

Hope this helps some of you out . I always enjoy the comments .

Kinghappy , The Godfather of Lithium .

3 Likes
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Good Info @LithiumGods !
I just acquired a 2011 E6 to flip. FS rebuilt the T4 and took the limits off. Checking the program later today. Any Suggestions while I’m in it?
7 hp and instead of the 9-8volts I installed 6-8G31 Deka gels. I’m thinking of adding the 7th to up the overall stats.
What are your thoughts?

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You can add a 7th but you have to figure out how to charge it . The Gem will love it . FS might have locked your controller . Let us know if you can get in .

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OH!? I will run out there now to see. Will be back to you shortly.

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I could not connect to the FS controller. Tried changing ports with no luck

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Can the DQ be reprogrammed for a 7th battery algorithm?

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No you would need a 84v charger . @Inwo had a guy put a extra battery with dedicated charger right before controller and it worked .

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I charge the first 6 batteries with the Zivan. for the 7th battery I have a small 6 amp mini charger with a read out. I plug both in at the same time. Always 100% in the morning

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This is the thread Mike was referencing LiFePo4 "7th battery" on a lead bottom GEM

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@LithiumGods What are the setting for regen? I am swapping parts with my guy tomorrow and he’s bringing his controller.

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decrease 19 and 20 . Try 100

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@LithiumGods Cool, thank you.

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Fyi , I turned regen to 1 once . Let off the gas and almost put my nose into the windsheild . I think there is a differnece in regen depneding on type of battery pack .

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Bigger numbers equal less regen.

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Which controller?

On a T2, 20 is not a regen setting.
#19 is "FIELD CURRENT RAMP RATE DURING OVERSPEED PEDAL UP REGEN "
#20 is "MPH OVER SPEED LIMIT "

Other regen settings on a T2:
#9 is “REGEN ARMATURE CURRENT LIMIT”
#10 is “REGEN FIELD CURRENT LIMIT”
#21 is "ARMATURE CURRENT RAMP DURING PEDAL UP REGEN "

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I was refering to a T4 or T5 . Just looked at the T2 manual . It does it differently . It apprears you would raise 9 and 10 to increase regen amps . I have not done it with a T2 so cant be sure .

The t4/5 you can adjust amps but there is another setting that allows you to adjust the amount of regen . #19 &20

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Thanks Mike. I’ll give those settings a try this weekend.

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Thanks for the update. I guess I should have been more clear on what controller I have.

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Well unfortunately, changing the #9 and #10 settings didn’t seem to make any difference or it was so minimal that it wasn’t noticed. I kind of saw this in the other threads. No one really mentioned any success. Thanks for looking into it I guess in the end though the T2 just isn’t going to do regen braking.

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If the 7th is still in the series, how can the 72 volt charger can charge the 6 while the 7th is in the circuit? I do understand the dedicated charger wired to the 7th.