# GEM e2 NEV Battery Upgrade



## CPseudonym (Apr 10, 2013)

Greetings, if this is a topic that has been beat to death please forgive me I'm new here  If a link to another thread answering my question can be provided by those more used to navigating this forum, I'd appreciate it. My keywords are too short or vague for the forum search function and yield no results.

I have a 2005 GEM e2 NEV that is equipped with six 12 volt lead acid batteries that are at the end of their useful life. I was considering upgrading to gel style batteries until it was suggested at a boating forum that I look into LI batteries. 

This forum was suggested as a great resource for this kind of information. The problem I have is while I'm sold on the electric vehicle concept and a happy owner of one, I lack technical expertise and come here seeking to learn from this body of expert enthusiasts.

Thank you for any help you may be able to provide.

Craig


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## CPseudonym (Apr 10, 2013)

http://www.notepad.org/gemcar/2005/e2techsheet.pdf

The above is a link to the technical specs I have for the vehicle if this helps.

Craig


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## Ziggythewiz (May 16, 2010)

Most of us are or are trying to move to LiFePO4 cells. ~1/4 the weight and space and 2-3000 cycles.


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## CPseudonym (Apr 10, 2013)

Thank you, that is the battery that has been recommended to me and was having trouble remembering what to call them. 

If switching from flooded LA to LiFePO4 cells do you believe the vehicles existing onboard charging system will still work? I imagine that will need upgrading too. 

I currently have a GE 72 volt 5 HP motor. The speed controller is another concern of mine. 

Sorry for all the questions, perhaps I should have been spending the last 3 years planning for this eventual technology leap instead of blindly enjoying our car? Until this week we where operating under the assumption that gel was our only option for upgrade. It may well still be the only practical one for our application but after being introduced to the LiFePO4 possibility I feel compelled to research it. I am so un-familiar with LiFePO4 that I feel like a blind mole in a maze  But at least now, thanks to you, I know what to research and I thank you very much for that. Suppose it's time to search the archives of this site for LiFePO4.


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## major (Apr 4, 2008)

CPseudonym said:


> If switching from flooded LA to LiFePO4 cells do you believe the vehicles existing onboard charging system will still work? I imagine that will need upgrading too.


Hi CPseudo,

I did a Gem battery replacement for a client last fall. It was Pb to Pb. Here is the story: http://www.diyelectriccar.com/forums/showthread.php?t=78826 From that experience, I can tell you it will be easiest to stay with PbAcid from the install standpoint. And you might be served well with a new set of Pb batteries. Here is a happy camper with Pb in an NEV: http://www.diyelectriccar.com/forums/showpost.php?p=350002&postcount=10 

I don't think gel type batteries are a good choice for deep cycle applications. But do get a good (actually maybe the best you can find) quality PbAcid battery from a dealer who will offer warranty. And if the new batteries are different (type or brand) from the old ones, you may need to change the algorithm on the charger. If it is the DeltaQ it will have a number of them stored and you'll need to select the proper one. 

If you desire longer range or extended life then LiFePO4 is a reasonable approach. It will require modification to the hold-downs and probably cables. It needs some type of BMS or at minimum a monitoring system and that will be different from the existing battery "fuel" gauge. It will also present the need to alter the charger. The DeltaQ is a good quality charger and they are capable of Lithium battery charging, but the GEM charger may not be easily adapted to this. Ref: http://www.diyelectriccar.com/forums/showthread.php/delta-q-not-charging-after-lifepo4-84726.html

I'd check around and find some forums dedicated to GEMs or NEVs. Maybe some GolfCart forums might have sections on these vehicles or otherwise provide some insight. Check to see if there is a GEM dealership or service center with whom you can seek advice.

Regards,

major


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## CPseudonym (Apr 10, 2013)

Thank you for the great feedback Major. A lot of meat for me to digest but I'm up to the task 

I actually wondered if this might be the wrong forum for my NEV after noticing the sub forum for factory built cars lacked NEV's. Nevertheless I am very happy to have joined your community and have been stunned at the body of work you folks have on the subject. I have an older Toyota pickup that converting to plug in electric has been on my mind for sometime. Who knows, seeing what you guys have done here may well inspire to follow that route. Wife and I are perfectly happy with our NEV and have a lifestyle that lends itself to electric vehicles. 

Thanks again Major.


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## rmay635703 (Oct 23, 2008)

Actually those of us lucky enough to have low and slow EVs are best served by Lead, my fathers 40 mile minivan and my 50 mile C-car both run lead with very low amp draws, in these applications its cheaper and easier just to keep the lead.

One suggestion is to consider modifying your "cart" for 8v or 6v lead batteries, you may need to add some helpers if it has springs or mock up another box. If it has provided good service with 12v batteries I guarantee you will enjoy 8v even more if you buy the right brand.

My fathers minivan was WELL served by moving from 12v to 6v batteries, the original giant 12v provided a reliable 30 mile range while they worked, the 12v Trojans gave about 12 miles and the 6v Greensavers give a nice reliable summer range of 40 miles. 

I have to say I have no real complaints running lead all these years. And yes I really abuse the crap out of them.

Cheers
Ryan


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## CPseudonym (Apr 10, 2013)

Thank you Ryan. This started as a research project for longer battery life and believe I'll just replace with lead this time around and consider upgrading at a later date. Frankly I have no desire to go without use of my Gem for longer than needed as I enjoy using it as is. Spring is the time to drive me VEV, not modify it. I'll treat this subject as long term feasibility for a winter mod.

The promise of more charge cycles with LiFePO4 I still find very appealing and will further research the issue for a future upgrade. $1,200 will cure my current problem. LiFePO4 plus charger, controller and tray/bracket mods will certainly be more pricey and I wish to get it right the first time. I'm willing to budget $4,000 for this modification to my Gem in the near future, if I can make it happen for that I'll pursue it.

After more research of the site archives I may start a thread investigating the feasability of a possible conversion of my 1998 Toyota Tacoma. 

Thanks to all, you've been a great help to me.

~Craig


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