New GEM Owner - Converting To Lithium Batteries

GEM Forum
21

[QUOTE=bgeery;15488] I’m excited to have another lithium powered GEM running around somewhere (yours will make a total of three LiFePo4 powered GEMs that I’m aware of… [/QUOTE]

I’m excited to get this one on the road. Lot’s of news to report including a new NG3 charger and yes, all 25 CALB 100Fi’s fit under the seat of my 825e!

And a few more questions…thanks so much for letting me pick your brain.

[QUOTE=bgeery;15488] If you are willing to spend the money, why not get a PowerLab! I’m cheap, so I just used big fat 300 Watt 0.05 Ohm resistor to do the bulk discharging manually on each cell. …a PowerLab would be neat to own, and certainly makes the job easier. [/QUOTE]

Yes… I’m thinking about the PL6, considering the big resistor is $50+ and then nearly a month of bottom testing. Sounds like I could do the whole bottom balancing act in a week…

[QUOTE=bgeery;15488] Elcon … will then select something from their stock Zivan profiles that is close to what you choose. [/QUOTE]

For the new NG3 I just picked up, Elcon is recommending profile “501b” which charges to 3.5V and then floats at 3.4V (I’ll try to attach a graphic…if my junior status allows…)

[QUOTE=bgeery;15488] Elcon will give you something close enough to work with, but it will need tweaking to be right [/QUOTE]

:spy:

[QUOTE=bgeery;15488] I drilled a hole in the case so I could adjust the trim pots without having to remove the charger from the car (but I still have to take off the top half of the dash.) [/QUOTE]

While charging, I adjusted the current trim pot until current would not further increase. Don’t keep turning the trim pot past the point where the current stops rising, as the charger seems to act strangely in that case. Also, watch out when you have the NG1 open-- the metal parts are live with 120 VAC! That’s anther good reason to drill the hole for access.

Great idea! I wonder if the NG3 has a similar setup with the pots?

[QUOTE=bgeery;15488] The 35-40 Amps available from the NG3 would be a better charger for someone using most of the pack capacity each day. [/QUOTE]

So I found one on eBay and decided to spring for it…with the hills here in SF, I expect to run down my pack on a daily basis.

I’m trying to get a straight answer from Elcon on the max potential Amps available from the NG3 at 115V. They’re recommending 20A @ 115V but won’t tell me the max available. I can easily install a dedicated circuit from my panel to power the charger…but I’m thinking the GEM-side charging circuit wiring into the charger would need an upgrade too. Any thoughts on this would be appreciated.

[QUOTE=bgeery;15488] I’m averaging about 145 watt-hours/mile. So with 11.5KW-h available in my pack down to 90% depth of discharge, I have a range of about 80 miles.[/QUOTE]

Nice! With some of my tools on-board, I’ve been estimating 150 watt-hours/mile with 6.4KWh giving me a range of about 42 miles, with my pack. I think that will be fine for my daily usage, but I’m eager to find out what’s real…

[QUOTE=bgeery;15488] Do you currently drive your GEM on those insane SF hills? Do you have the stock 5HP motor on your GEM? [/QUOTE]

I do the hills when necessary, but I take all the less steep routes whenever possible, which means some round-about journeys through the back streets of my beautiful city! I did upgrade to the 7.5 ride-4-fun motor when i got the GEM and it does a fine job: mostly takes steeper hills @ 20mph+, & no overheating. When I pushed it uphill, I’d sometimes get some front end tire-bounce up steep hills, with the stock 13" wheels (which I’ve now replaced with some 16" low-rolling-resistance beauties, so I’m hoping for a smoother ride!).

Overall, my Biggest problem by far was the lack of battery life with the LAs. I only got one round-trip across town–about 12-14 miles out of that old setup. Not good enough to make the GEM my primary service vehicle.

[QUOTE=bgeery;15488] Reprogramming the controller might also help with performance and tweaking the regen settings might be a good idea while you’re at it. I can’t think of a more challenging city for any EV.[/QUOTE]

Hmmm…Pls tell me more about reprogramming the controller and tweaking regen settings, if you would. :High5:

[QUOTE=bgeery;15488] The current 12V DC/DC converter used for the lighting is already sized to handle a stereo. And everything you listed, except perhaps the seat heating.[/QUOTE]

Yes, it will do it, at least initially. Eventually, amplifying sound may require another solution.

Thanks for the seat-heating tips too! The Flexwatt option looks interesting, but it’s 115VAC. Are you thinking I’d use something like this… futurlec. com/Relays/SSR10Apr or?

And many thanks for the Cycle Analyst link. MUCH better that the other options I was considering, though I’m tempted to look at making something with the Arduino eventually :crazy:

Again, many thanks for all the valuable tips and insights! It’s really great to have help thinking this through! After this post, I should be eligible to post pics and URLs on this forum… I’m eager to share the interesting ones with you!

22

[QUOTE=timo;15725]For the new NG3 I just picked up, Elcon is recommending profile “501b” which charges to 3.5V and then floats at 3.4V (I’ll try to attach a graphic…if my junior status allows…)[/QUOTE]That sounds like a nice conservative profile. Of course, you’ll probably want to tweak the voltage down a little so you are floating under 3.38V (the true full voltage of LiFePO4 chemistry) on your highest vlotage (weakest) cell. But that default profile sounds like very close to what you want. As you are going with the NG-3, you also could probably get that replacement programmable chip working as-is-- assuming you could find a way to get one without having to buy 10 of them!

I wonder if the NG3 has a similar setup with the pots?
Yes, they have the pots too. They may not be in the same spot, however. Once you get the lid off, you’ll find 'em.

I’m trying to get a straight answer from Elcon on the max potential Amps available from the NG3 at 115V. They’re recommending 20A @ 115V but won’t tell me the max available. I can easily install a dedicated circuit from my panel to power the charger…but I’m thinking the GEM-side charging circuit wiring into the charger would need an upgrade too. Any thoughts on this would be appreciated.

20A is all you can get out of anything from a 120 socket. I wouldn’t recommend anything over 15A, because it’s harder to find a 20A socket when charging on the road. The current wiring/charge socket probably needs an upgrade for use @ 20A anyway.

If you can run a circuit , you best charge @ 220V at home. You will then be able to charge as fast as the NG-3 will allow. Save the 120V charging for on the road use. I’m assuming the NG-3 can be wired to charge from both 240V and 120V?

Hmmm…Pls tell me more about reprogramming the controller and tweaking regen settings, if you would. :High5:

You can buy a programmer to adjust your controller settings. Marlon is the best guy to talk to regarding reprogramming the controller. You can adjust the speed limit, recalibrate you spedo to read correctly with your larger tires, increase the power to your motor, and adjust the way regen works. I haven’t done it yet myself, yet. With your R4F motor, I believe you could get much better performance out of it with reprogramming.

Eventually, amplifying sound may require another solution.
You can install an additional DC-DC converter if you need additional 12V power, like this 29 amp one. Are you really thinking of installing a sub-woofer on a GEM. :lol: That will be a first. :rockon:

Thanks for the seat-heating tips too! The Flexwatt option looks interesting, but it’s 115VAC. Are you thinking I’d use something like this… futurlec. com/Relays/SSR10Apr or?

Heat tape will work on any voltage, AC or DC. The 11" 20 watts/foot stuff will put out 9 watts at the 85 Volts of the main battery pack. Total heat would be about 3 sq. feet per person (seat and backrest combined), or about 27 watts (97 BTUs) of heat. Is that enough heat? Seems to be about half the power of some 12V car seat heating pad kits. You could double the heat by instead using four rows of the 3" 10 watts/foot tape. That would get you to about the heat output of the 12V equivalent solutions.

Maybe no need to control the temperature, and just use a 150VDC breaker as an on/off switch. For heat control, add a dumb rheostat-style (you may have problems finding one) light dimmer.

The one disadvantage of using a breaker is you would forget to turn the heater off and drain the pack. That’s where using a contactor or SSR (controlled via toggle switch and the 12VDC) has the advantage, but costs more.

If you had more 12V current available from the DC-DC converter, there are plenty of 12V car seat heater kits for sell on ebay.

If you want a lot of heat, they make 72VDC 18K-24K BTUs heaters for reasonable money, available here Not a bad idea, assuming you have doors of some kind.

23

I Talked with Dustin of Inovation motors in Mesa AZ. about chargers. He says Zivan charger and are not very good. He says he has a bunch of them in his storage from those who have changed to the quick charge. Probably could buy one cheep.
Have A Hot Day
Chili Willy

24

Hello. I am Jeffrey. New to this group. I have a 2002 Gem Car with probably 1 yr left on Trojan batteries. I am in LA, CA. I would like to convert to LITHIUM batteries within the next year. Anybody who has done this already, I would appreciate any help. I believe I have the non-user programmable Zivan Charger. ANY INFO/HELP APPRECIATED!

25

[quote=nakedwaterskier;23846]Anybody who has done this already, I would appreciate any help. I believe I have the non-user programmable Zivan Charger. ANY INFO/HELP APPRECIATED![/quote]Did you read through this thread? What specifically do you need info on?

26

I read through it. I am a gearhead not a chiphead ie I am fairly mechanically inclined but not electrically inclined. I am afraid to start tinkering/upgrading unless I can find a reliable source of knowledge. Right now this site is blocking any personal messages…I have no idea how I could have offended somebody already. But, in any case, I am definitely not about to start upgrading till I have an easy free flow of info with this site and/or with someone who has already done what I want to do. Oh, I already upsized my wheels and tires. Thanks in advance, Jeffrey

27

Remember, you are not making an EV here, just changing the battery technology. It’s not that hard, and is mostly a mechanical task. Find batteries that fit, find a way to hold them down, wire in series, send out charger to be reprogrammed.

The best summery of all the steps I went through is in post #9. Read that and look at the pics (some of the source links are defunct now.) If you have questions, ask and I’ll clarify.

The only other step you may choose that I didn’t, is adding a BMS (battery management system). I don’t have one, and just manually monitor my charge progress.

1 Like
28

Thanks…I will read up and get back to you with more questions. Thanks again. Jeffrey

29

Oh since you have the same year…do you have pics? or did you post pics?

30

[quote=nakedwaterskier;23856]Oh since you have the same year…do you have pics? or did you post pics?[/quote]See, this is how I know you didn’t read this thread. :rolleyes: Yes, the pics are here in the thread. Read the thread (at least my posts up through page 2), write down the questions you have, and I’ll help you out. I have a TON of info here, but I’m sure I must have glossed over something.

31

A few things come to mind after the first read of #9. My original GEM Zivan charger is reprogrammable for Lithium or trash? I already put bigger wheels on so doesn’t that do away with much the speed limiting problem? Aren’t lithium batteries supposed to be denser than my Trojans? So, can’t lithium batteries be found that fit better/easier with fewer mods?

32

Sorry, I went straight to #9 and evidently missed the pics.

33

OH OK…I saw your small thumbnails at the bottom of #9. But, when I click on your thumbnail pics I get this error message: nakedwaterskier, you do not have permission to access this page. This could be due to one of several reasons:

Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?
If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.
34

I don’t know if I am already getting the boot, don’t know what I am doing, or the website administrator hasn’t given me access yet or is pissed at me.

35

I definitely do not want to even to start tackling a job like this till I understand how this website works and whether I have violated rules and that is why my access is limited or whether since I am new, I just am not allowed access to certain things like your pics yet.

36

I also tried the link to Current EV Tech which doesn’t seem to work. I also found posts by several people who had problems with them. My Trojan Batteries are still OK. So, I will probably just wait another 6 months. That way Lithium batteries/packs will come down in price some more and I will let early adopters like you pave the way more so I don’t get stuck half way through my GEM upgrades.

37

Current EV tech is a dealer that went under soon after I ordered from them. I ordered from them because they were the only source at the time… CALB in California is probably the best source today. Prices on batteries has not come down much over the last few years.

I just checked, the the pics work here. Did you verify your account via email link (don’t know if this forum does that or not)? That may be why you can’t view pics. You can also see them on the Yahoo Groups NEV group (you have to sign up as a member) in my photo album.

38

I did use the finish signup link. And I still could not view your thumbnails. I will try the yahoo forum. I hope it is more user friendly than this forum. Thanks again.

39

OK, I just uploaded the pics to 2002 LiFePO4 Lithium Conversion - Album on Imgur (no account needed.) Take a look at the pics, and read the text in my posts here, and it should mostly be clear how easy it is on our older models.

40

I was trying to find CALB in California. Their China website didn’t work. I found somebody in the DIY Electric Car Forum that wrote about visiting the facility but he called it CALIB which I think is a typo. Anyways, he is from Reseda, CA which is right near me so I am going to contact him. Thanks.