# Gem e2, 2 seater 2002 E825 Lithium Upgrade(tighter fit) **URL:** \ **Category:** GEM Forum\ **Created:** [February 10, 2017, 7:15pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042 "2017-02-10T19:15:48Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 13, 2017, 1:16pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/103 "2017-03-13T13:16:45Z")
Charger is out for reprogramming. Then we will fine adust with pots afterwards. The BMS bars/hookups are bridged because we are paralleling. ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 15, 2017, 11:28pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/105 "2017-03-15T23:28:18Z")
The Nissan Leaf battery pack is made of 192 Lithium-Ion (LiMnO2) cells, in a 96s2p configuration. Each cell is 32.5Ah @ 3.75V nominal, (3.2V - 4.2V). Four cells per module in a 2s2p configuration. And with 48 modules in the pack, this results in a 65Ah @ 360V. SO HOW DOES ONE CALC AMP HOURS? ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 15, 2017, 11:33pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/106 "2017-03-15T23:33:03Z")
nominal vs min cell voltage? anyone? ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 15, 2017, 11:37pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/107 "2017-03-15T23:37:10Z")
Depending on the design and chemistry of your lithium cell, you may see them sold under different nominal “voltages”. For example, almost all lithium polymer batteries are 3.7V or 4.2V batteries. **What this means is that the maximum voltage of the cell is 4.2v and that the “nominal” (average) voltage is 3.7V. As the battery is used, the voltage will drop lower and lower until the minimum which is around 3.0V.** You should see the number 3.7V written on the battery itself somewhere. ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 16, 2017, 5:44pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/108 "2017-03-16T17:44:43Z")
INFO FOR DEALING WITH ELCON, I AM POSTING IN TWO PLACES BECAUSE SOMEONE ELSE MIGHT NEED THIS INFO; MAKES IT EASIER TO FIND To ``` Electric Conversions ``` Message body I did not know how to figure amp hours. A friend finally emailed me the info. I attached his commentary at the bottom. CRITICAL INFO I PUT IN BOLDFACE SO YOU DON’T HAVE TO GO THROUGH IT ALL. And I shipped by USPS. Supposed to arrive to you tomorrow Saturday. Please let me know how and when to pay for the reprogramming. Thanks, Jeffrey Gillette Tarzana, CA 91356 8189160787 2002 Gem Car with Zivan Charger OEM BMS 24 [Chargery.com](http://Chargery.com) Battery Chemistry Lithium with lithium-manganese-oxide nickel oxide Cathode from 2013 Nissan Leaf Each Cell is rated at 32.5Ah OR 75V \* 65Ah = 4,875 Wh = 4.875kWh. (at Nominal see below) 20 Cells x 500W = 10 kWh Max. Cell Voltage 4.2V times 20 = 84V Nominal Cell Voltage 3.75V times 20 = 75V 20 Cells x 500W = 10 kWh USE ONLY 80% OF CAPACITY TO PRESERVE CYCLE LIFE SO MAX DESIRED CELL VOLTAGE: 4V times 20 = 80V CUT THAT TO 78V nah nevermind; LEAVE AT 80V MAX MAX CELL VOLTAGE 3.9V times 20 = 78V MIN CELL VOLTAGE 3.0V times 20 = 60V Please see boldface last paragraph below The Nissan Leaf battery pack is made of 192 Lithium-Ion (LiMnO2) cells, in a 96s2p configuration. Each cell is 32.5Ah @ 3.75V nominal, (3.2V - 4.2V). Four cells per module in a 2s2p configuration. And with 48 modules in the pack, this results in a 65Ah @ 360V. I am using 20. Per a Friend named David: Amp-hours add in parallel, voltage adds in series. Volts \* amps = watts which also means that Volts \* Amp-hours = Watt-hours. To estimate the kWh of a pack the nominal voltage is typically used though depending on the load the pack is under the actual amount of useable energy can be different. I assume you have a string of 20 cell pairs meaning that you have a 2p20s arrangement. If this is the case you add the Ah of the 2 parallel cells and get 65Ah. Next you add the nominal voltage of the cells in series which gave you the 75V figure. 75V \* 65Ah = 4,875 Wh = 4.875kWh. As for using only 80% of the cell capacity, the reserve should be at BOTH ends of the charge/discharge curve. I don’t recall what Nissan uses for the top and bottom end but I would start with stopping when the cells are 95% full on charge and consider empty when there is 15% left at the bottom end. Also, if you can have a lower cutoff point for when you don’t need the full capacity then I would only charge to 80% for daily use. In fact, my Kia Soul EV cuts off at about 78% actual battery capacity when the dash says 80%. The dash only shows available capacity to the user not the actual battery capacity so the only way I know of to charge the battery over 95% actual SOC (state of charge) is to charge fully at the top of a hill and then regen down the hill. It looks like your Gem system is calibrated to 78V target voltage. What I would do is charge to that point and then just before the charger shuts off adjust the voltage trim pot a little to raise the voltage a little at a time. If you turn the pot and the charger stops charging you probably turned the pot the wrong direction. If the charger shuts off before you are finished just restart it and it should cut back quickly so you can continue to adjust. If it is quiet enough and your hearing good enough you can hear a high pitched whine from the Zivan charger when it is charging. This whine will stop and start several times at the end of charge. This is when you want to adjust the voltage trim pot. Adjust a little at a time so you don’t go too far. HTH, David ---
**Author:** ![Todd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/todd/32/1061_2.png) [@Todd](https://community.electricforum.com/u/Todd)\ **Post date:** [March 23, 2017, 9:15pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/109 "2017-03-23T21:15:17Z")
> [@Troyin909](#): > > Hey Todd can you post some pics of your setup when you get done. ![](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/1X/b486f9c44a357c00dc412f9cc1c96aefd23aeb25.JPG) ![](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/1X/d1ee4d7dcf4b5ff0322d8b11cf7bfe08e8d18770.JPG) I think that I might mount the BMS on the top of the front battery pack with velcro or two sided tape. I’ve been monitoring the individual cells after every charge and now I’m checking them as I am discharging them. I’m pretty confident that the BMS won’t need to be where I can keep an eye on it all the time. Heading ---
**Author:** ![Troyin909](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Troyin909](https://community.electricforum.com/u/Troyin909)\ **Post date:** [March 23, 2017, 9:43pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/110 "2017-03-23T21:43:30Z")
Looks nice Man!!! Clean.whats BMS are you going to use. Troy Hoggard’s iPhone ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 23, 2017, 9:45pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/111 "2017-03-23T21:45:37Z")
> **[GemCar by Hal Gottlieb](http://s943.photobucket.com/user/halgot1/library/GemCar)** > > BMS - View the full album on Photobucket. I only have the temp sensors going to the pack closest to the dashboard; that is all the length the Blue BMS24 wires have. I did extend all the BMS current/voltage sensors/leads though. I used wiring looms, tape, cable ties, and heat shrink tubing to make sure none get frayed on sharp edges… ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 23, 2017, 9:45pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/112 "2017-03-23T21:45:59Z")
> **[GemCar Slideshow by Hal Gottlieb](http://s943.photobucket.com/user/halgot1/slideshow/GemCar)** > > BMS - View the slideshow on Photobucket. JUST WAITING FOR ELCON/ZIVAN SACRAMENTO TO REPROGRAM MY ZIVAN CHARGER! I hear this is a common bottleneck. Jeffrey ---
**Author:** ![Todd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/todd/32/1061_2.png) [@Todd](https://community.electricforum.com/u/Todd)\ **Post date:** [March 23, 2017, 9:50pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/113 "2017-03-23T21:50:08Z")
> [@nakedwaterskier](#): > > JUST WAITING FOR ELCON/ZIVAN SACRAMENTO TO REPROGRAM MY ZIVAN CHARGER!I hear this is a common bottleneck. The biggest problem that I had with them is communication. They absolutely refused to let me talk to the tech. Questions could have been solved in minutes on the phone took a week worth of emails. ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 23, 2017, 9:54pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/114 "2017-03-23T21:54:25Z")
I tried to bribe them with a pizza lunch but they said the reprogrammer was out of town. ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 23, 2017, 9:56pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/115 "2017-03-23T21:56:46Z")
So, you are using only 11 Leaf modules? ---
**Author:** ![Todd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/todd/32/1061_2.png) [@Todd](https://community.electricforum.com/u/Todd)\ **Post date:** [March 23, 2017, 9:57pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/116 "2017-03-23T21:57:19Z")
> [@Troyin909](#): > > Looks nice Man!!! Clean.whats BMS are you going to use. The one from Dave “INWO”. I have it, just wasn’t sure where to put it. I mounted a digital volt meter in the dash to monitor overall voltage, so I’m thinking that the BMS can be under the hood. It’s only one quick release fastener to unclasp if I want to check on the BMS. I’m just loving the increased acceleration that I’m getting from the extra voltage and lost weight. It does ride a bit rougher now, though. I even put 5 flats of shotgun shells under the seat to add some of the weigh back. ---
**Author:** ![Todd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/todd/32/1061_2.png) [@Todd](https://community.electricforum.com/u/Todd)\ **Post date:** [March 24, 2017, 12:37pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/117 "2017-03-24T12:37:06Z")
> [@nakedwaterskier](#): > > So, you are using only 11 Leaf modules? Yes, 11 modules. It is currently working great, I am making a lot of short trips daily and charging every 3 or 4 days. ---
**Author:** ![Troyin909](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Troyin909](https://community.electricforum.com/u/Troyin909)\ **Post date:** [March 24, 2017, 4:13pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/118 "2017-03-24T16:13:02Z")
im not sure what my deal is but I think I have a controller issue! My range doesn’t seem to be as far as is should be with 20 modules in my 4 seater. Send a pic when you get the bms all in. Im going to start on mine soon. [troyocfa@gmail.com](mailto:troyocfa@gmail.com) ---
**Author:** ![nakedwaterskier](https://avatars.discourse-cdn.com/v4/letter/n/258eb7/32.png) [@nakedwaterskier](https://community.electricforum.com/u/nakedwaterskier)\ **Post date:** [March 24, 2017, 4:30pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/119 "2017-03-24T16:30:42Z")
Measure your amps and volts when fully charged. > **[How to Measure Amperage](https://www.wikihow.com/Measure-Amperage)** > > Amperage is the amount of electrical current running through an electrical component, such as a wire. Specifically, amperage measures the number of electrons passing a given point in a given period of time, with 1 ampere (or "amp") equal... ---
**Author:** ![Troyin909](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Troyin909](https://community.electricforum.com/u/Troyin909)\ **Post date:** [March 24, 2017, 9:09pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/120 "2017-03-24T21:09:20Z")
I’m going to try that today with my neighbors meter. ---
**Author:** ![Todd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/todd/32/1061_2.png) [@Todd](https://community.electricforum.com/u/Todd)\ **Post date:** [March 24, 2017, 11:02pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/121 "2017-03-24T23:02:57Z")
> [@nakedwaterskier](#): > > Measure your amps and volts when fully charged. Measuring amps without a load would be 0. Or are you talking about charging amps? ---
**Author:** ![Jeffrey\_Gillette](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jeffrey_gillette/32/791_2.png) [@Jeffrey\_Gillette](https://community.electricforum.com/u/Jeffrey_Gillette)\ **Post date:** [March 24, 2017, 11:35pm UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/122 "2017-03-24T23:35:45Z")
Running…also check for drain ---
**Author:** ![Troyin909](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@Troyin909](https://community.electricforum.com/u/Troyin909)\ **Post date:** [March 25, 2017, 5:56am UTC](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042/123 "2017-03-25T05:56:51Z")
Hell I didn’t know what I was doing. I’ll just have to get the BMS installed and let that tell me the rest. I was just trying to see if I could check the amp draw so I would know what my motor was pulling. Oh well I’ll try when I get back home from work in three days. Thanks fellas! [Previous page](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042.md?page=5) [Next page](https://community.electricforum.com/t/gem-e2-2-seater-2002-e825-lithium-upgrade-tighter-fit/12042.md?page=7)