Just purchased 2002 e825-4 where to start rejuvenation?

Yes, working great otherwise I would have posted to this thread.


We just had lots of rain in SoCA and I did have to run the GEM in it some and it was parked outside so she saw water and lots of it. A couple of days after the rain I went to take her out for a spin and when I got back and gave her 110VAC power to charge there was a 2 tone beeping coming from the Zivan and the dashboard LED was blinking yellow.

I looked up the code and it said the temperature probe was out of spec. Recalling that the temp probe was on a plug at the top of the Zivan charger, I unplugged it and was able to recharge the batteries. Looking at the sensor, it was in the bottom of the battery pan so it’s probable there was water in there and if the potting compound or seal had cracked, water got into the sensor.

My question for the group is what part is in the end of that cable so I can replace it since after 4 days of warm weather it still says the sensor is out of spec?

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Rodney says to run without it.
The Delta-Q uses a 10k thermistor. Pretty standard.
I don’t know what value Zivan uses.
Check value at charger and at sensor to see if its the same. Might be a connection.
If sensor is open or shorted it is most likely bad.

ha, if it’s just a thermistor then I might have a replacement in my 3D printer parts bags.

The fact it worked perfectly before the rain and even after I ran it for a bit in the rain and only failed a few days after having had to sit through heavy rains and the end at the batteries(sensor end) was wet I’m pretty sure it got moisture inside an is effecting its resistance.

I’ll dig around for what it’s valid resistance range is, make a measurement and see if something in my parts bins works.

I was going to zip-tie it to the metal battery post since that’s the best place to measure battery temp but like many things, I didn’t get to it in time.

The temp sensor is an LM335 IC

And the DIN connection is to pins 4 and 5.
Order is 1-4-2-5-3

Interestingly, I clipped off the sensor at the end of the outer casing(red and blue wire coating left on sensor end for patching later ) and yet when I plug in the DIN connector I still getting the blinking yellow and beeping warnings.

Eventually, I will open the DIN connector and see what gives. I was hoping for at least keeping the charging LED.

Nice blog on LM35 and LM335 sensors


hint: common LM35( I have bunches of these ) is rated output in C while the LM335 output is in K( as in Kelvin)

Thank you for the heads up on the lights. I just purchased them on amazon !

Any other recommendations?

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Watch the the Bolt thread.
A lithium conversion that may overcome the weight distribution problem with early model Gems.

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Finally testing the 79.5V Trickle Charger using a 24V 5A surplus wheelchair charger($14) and a 1200W 12-83V-Out DC-DC converter($14). It had been charged the night before and by morning the float charge on the batteries was 75V. It is still a hack in progress and currently cost only $14 since I already had the other part(s). I will also be looking into a Zivan NG1 upgrade option to see if not only can it be upgraded to enable/include this trickle-charge feature but the Lithium charge capability too. And at what cost.

1200W 20A DC Converter Boost Step-up Power Supply Module IN 8-60V OUT 12-83V(6.8)

DC12V Power Supply 24V 12V 5A Power Adapter 110V 220V AC to 12 volt Transformer 10A 15A DC24V Power Supply for LED Strip

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after leaving it on the trickle charger for 24 hours I was noticing the voltage kept at 79.2 - 79.5 with small periods of no charge current and others with only .4A so it seemed to work well.

On the first test, I was pleased to find it did a good 24 MPH up most of the slight hills and the top of the slight hill it did as before and only held to 22 MPH and then had 91% charge when stopped. What was strange was when 2 hours later I powered back up and saw the SoC was then at 75%.

I think I need to seek out where the current leakage is coming from and find where that 12V DC-DC converter is located. I did not see it under the dash last night when I checked on the trickle charger.

I finally got the LM335 parts from China and replaced the one on the problematic battery sensor but it was not the LM335 which was bad. You see, built a little Arduino circuit with the LM335 and a 1K resistor and a raw LM335 worked fine but when I jumped in the newly replaced tiny circuit board from the battery sensor, it showed -100 F. Wrong. Removed the tiny surface mount capacitor and it was shorted. Grabbed something of similar physical size from a scrap circuit board and after installing it, the sensor module worked fine.

I have some thick silicone heat transfer compound I will try encasing the LM335 in and then heat shrink it and maybe even insert a metal tab so it can be attached to a battery post for best battery temp measurements.

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Battery temperature sensor repair worked. I just stuck with putting a glob of silicone thermal paste on the end and let the heatshrink overhang a 1/4".

Just read thru your thread thanks for all the posts. I’m on the fence on buying a 2007 fixer, been using an Ezgo for the last five years. Have you solved your hard ride issues? How about the trans noises?

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I’ve not “solved” the hard ride issue other than it’s a much smoother ride when there are 2 adults in the car. The transmission issue was/is the rubber spacer inside the end of the motor spline socket. The first one I put in was not correct size but the next one was much better.

IIRC the suspension is much better on later models of GEM. I don’t recall the year it changed but for some reason 2005 rings a bell. Best to check through the forum though.

Thanks for the info on disk brake install. I expect to take it on shortly


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Discs were pretty easy to install and make a big difference in driving. Plus it’s so light they really don’t wear.

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Our 2001 Toyota Prius died due to my failure to get the transaxle fluid changed and it caused the big MG2 drive motor to fail. It’s been a good car but now it’s destined for the junk yard. But just last year I put 4 new low rolling resistant tires on it and with 14" rims and a 4 x 100mm bolt pattern, I’m hoping the e825-4 will be able to accept these new wheels and tires.

14" instead of 12" shouldn’t change the loading on the transaxle and motor much and probably just a couple of MPH while not having to mod the front or rear fenders. And the timing works since the GEM tires are just about needing replacement.

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I have not put the Prius tires and wheels on yet, nor put in the Leaf Gen4 lithium batteries. But the darn throttle switch is getting on my nerves( error -11 code ) so I found a replacement throttle micro switch for $3 and it’s on the way. https://www.onlinecomponents.com/honeywell/v15t16dz200a02-43415398.html

Will update if it works.
In the meantime, my replacement fuel pump and sender in the dodge diesel is way off and I ran out of fuel at just under 1/4 tank. Towed home and after 3 days still can’t get it primed to working. ugh.

UPDATE: The new switch fits perfectly but, didn’t stop the -11 code on rough roads or accelerating on full charge. I had a feeling it would not since I had removed and cleaned up the original and the spring tension in the switch and contacts seemed fine. It has seemed to reduce the occurrences some.

Going further, I have opened up the steering column and popped out all the switches and one by one inspected the contacts. All were nice bare copper looking except the Forward/off/Reverse switch. All 3 contacts were covered in a thin film of something looking oily. Contact cleaner on a Q-tip cleaned the and I sprayed in the connector too. This was a surfer shuttle so maybe sunscreened oily fingers on the button slowly worked into the switch. So I’ll give the switch itself a spray of contact cleaner too. Update to follow.

I have noticed that when I get lots of -11 codes, if I rapidly cycle the forward/reverse switch it throws the -11 code far less. I think I need to swap it with the turf switch.

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