Gem E2 battery question


Your observations are spot on. I have contacted East Penn for clarification.

Your comment on Lithium holds true from a performance stand point. HOWEVER: you are trading a dead simple system of 12 power conducting wires and a charger to a complicated system of 12 or more power wires and a minimum of 36+ monitoring wires a Battery Monitoring System and a charger.

IMHO its too early to mainstream this system for the average user. Currently talented performance oriented guys are having a ball. As experience and reliability increase it will become more mainstream. At this point the reliability for "start, run’and park "owner that expects 10 years of trouble free ownership isn’t there yet.

Your comments.


Old_Housboater, can you give me your opinion on the batteries I described in my original post? I respect both your knowledge and your willingness to share it. If you say no, I will keep trying to find the DCM31, but if you say these will work for our not high demand use, they are what I will purchase and install. Supplier is less then 2 miles from our home.

Grace, Peace and Joy be with you today.

At this point in time I can only recommend the 31DCM

I reviewed the East Penn (maker of Orielly batteries) product list and cannot find a reference to the 31DCMJ.

i have sent an inquiry to East Penn and I will share the results when I get it



Thank you. I wrote to O’Reilly corporate/on line ordering last night and it appears they may now have 1 at one of our stores and can get more. Will update.

Grace, Peace and Joy be with you today.

Rodney - you are a huge asset to this site and all of us who are trying to keep our GEM cars running and you make some very fair points. I’m hoping that time proves you wrong but I absolutely concede that we don’t have any long term data to support our hopes and expectations. I hope/believe that time is going to prove that lithium provides better performance, less work/hassle and lower overall cost of ownership.
I’ve just completed my lithium upgrade and haven’t had time to post my build experience yet but I will share the high level overview:
Purchased a full set of Chevy Volt batteries from a junkyard for $1,000 + $249 shipping. I have enough batteries to do 2 cars with 8KWH each so I’m in $625 for batteries themselves per car(I have 2). I chose to buy the BMS so that I can monitor and control my charging but I’m not convinced it was necessary but for my first car I’m happy that I have chosen it. That added $320. Had I opted to forgo it, I would have used less cables in total to wire my 4 batteries into the car than were needed for the lead batteries. I spent a day of labor stripping the batteries out of the Volt packs and probably $25 worth of misc. hardware and sawzall blades, etc… I bought Dave’s voltage spoof because I wanted to hotrod it. I could have done the lithium without it but wanted to use the extra voltage for the fun factor.
In the final analysis, I spent less than $1000 to upgrade to a hotrod lithium setup that is giving me well over 30 mile range in my community that has no flat roads. You are either climbing or descending here, never going flat and I can do it all at 25MPH+. IF we are correct in our expectation of longevity, these batteries should easily last 10-20 years with zero additional expense or work. Contrast that with lead acid and there’s no comparison. My FLA batteries were an absolute nightmare to keep watered and properly charged, my lithium can be stored at any state of charge and actually prefer to be stored less than full without degradation. My AGM’s never gave me more than 7-10 miles of range in my neighborhood. My car is almost 400lbs lighter and its like having power steering with the weight removed from over the front axle.
That’s the sales pitch. The downside for sure is that its not a plug and play installation and it requires some mechanical and electrical know-how and lots of patience but if it turns out like we expect, the payback for that upfront investment is going to be huge.
In the spirit of your response, I fully concur that the process is not for everybody as it stands today and lead batteries absolutely still have their place. I’m just delighted that my garage is no longer one of those places :slight_smile:

Happy Memorial Day to all. Here is the latest news on my search for batteries. I wrote to o’riellys on line ordering and received a reply that our local store had 1 DCM 31 and could order more for no shipping cost. Went over to the store today and again was told “no can do”. So I am asking the parts guy why on line says you have 1 and you can order without me paying any shipping. He says he does not know. The clerk next door over hears us and says he talked to corporate yesterday and here in California they add a Jo to the part number for some reason, here its a DCMJ31. So I ordered 6 and they will be here tomorrow. Thanks all.

Well it is California. Sacramento probably decided that the DCM31 was an assault battery and banned them so they had to change the part number. LOL

Could be, there is not a regulation we won’t screw up here. I am very happy the clerk that spoke to the lady from corporate was over hearing my conversation.

Ken and Karen Stockton

31DCMJ is a different battery. I am in process of pinning it down. Different specs different case.


Dang, this should not be so hard. They are due in the store today.

Ken and Karen Stockton

31DCMJ Is Manufactured by Johnson Controls. Looks like Orielly is changing Suppliers.

I contacted Johnson Controls today. The agent said that AH rating is not published in Orielly information but is about 106AH.

A couple of you have purchased a set of these batteries. Please keep us up to date on the performance

The 31DCM was/is Manufactured by East Penn and there product # is DEKA DC31DT This battery is available from other automotive out lets for about $10/$15 more than Oriellys.


New batteries are in. Took a 20 minute test run, speed is 22 mph with 2 men. Seems up to par for now but new issue is no horn, blinkers, headlights or wiper working. Where should I look? Maybe a fuse? Thanks.

Grace, Peace and Joy be with you today.

Fuse or DC/DC converter

In a message dated 5/31/2018 10:32:53 AM US Eastern Standard Time, writes:

Hi, where is the fuse and converter? Thanks again.

Ken and Karen Stockton

Open the hood. Fuse block is under the rubber flap on passenger side under windshield. Converter is he black box under the main contactor. Cart would not run if converter is bad.

In a message dated 5/31/2018 12:51:39 PM US Eastern Standard Time, writes:

So I pulled all the fuses and they tested good. Scratched my head, tuned the key and what do you know, all is working, there is a wire right above the main on/off switch that is grounded there, it was hanging loose and looked like it had for some time. It is small diameter??? Any ideas.

Grace, Peace and Joy be with you today.

Did anybody have any good luck with the 31DCMJ?

I have not heard of anyone who has chosen to try them. 31DCMs are manufactured by East Penn (DEKA) and are used by boaters for trolling, commercial users for floor scrubbers and lift equipment and are “Deep Cycle” rated. These batteries are available from other sources under different brand names at $20 $30 dollars higher. I would pay the extra to get that battery.

31DCMJ are made by Johnson Controls and are rated as a starting battery. I contacted Johnson Controls a year ago and they would not commit to rating these units as “Deep Cycle”

I understand that some areas don’t stock the 31DCM. Our area does so it hasn’t been a problem If you decide to try them please keep us up to date on your results. They may be equivalent but as long as I can get the 31DCM I wont take the chance.

In a message dated 10/6/2019 2:11:52 AM Eastern Standard Time, writes:

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For those that live near a Sams Club store (with no O’Reilly’s nearby), another option I believe for this battery is the 31DC. They are $99 there not including the core.

I believe it has same specs as the 31DCM (105 Ahr @ 20A rate, etc) and also made by East Penn. 1 year replacement warranty (so not great…) but again I believe the same as O’Reilly’s.

I’ve never used them in a GEM (haven’t started on mine yet…
:frowning: ), but I have used them on a manlift. Working fine now for 4 years.

That is the same battery,