[Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM

Wed Aug 1 11:43:50 PDT 2018

One thing I've experienced in the past is that the dual filament tail/brake/turn bulbs ground connection will corrode in the socket such that the filaments can't get to ground, but they are connected together at the now floating outer contact shell. Now when one filament is driven with 12V, say the brake filament, but the tail lights are not turned on, the brake light 12v path to ground may be back through the tail light filament. This can be quite a problem, depending on what the driving circuits for the different functions is. Old switch contacts didn't mind particularly, but electronic drivers without reverse diodes or other protection may not fare so well. The quality of the tail light housing and its seals is usually the issue. This is a particular issue with boat trailers which are used for wet launch as the lights may go under water for every launch and haul out. 

Paul 

From: gburket at peak.org 
To: "Gary Graunke" <gary at whitecape.org> 
Cc: "Corvallis EV CLub" <caevlist at caevclub.org> 
Sent: Wednesday, August 1, 2018 11:28:04 AM 
Subject: Re: [Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM 

The frig must be a small model. Tricks I've used with the plugs and receptacles is to keep the contacts clean with a wire brush (when they're not energized!), use a good dielectric grease on them, and spread or squeeze the poles slightly for better contact. If the plug and receptacle are too badly damaged, overheated, or corroded, they should be replaced. 

The ground problem is usually between the vehicles. The plugs and receptacles usually have a ground pole. The harness wires leading from the ground poles in the plug and receptacle are usually the most exposed wires, and most easily damaged. The trailer hitch receptacle and tow vehicle ball can act as a ground for the 12V systems between the vehicles - but it's not very reliable as the parts shift around. Sometimes the only solution is to set-up separate plug, receptacle, and wires for the ground. Better yet, set up a fused Anderson plug(or better) system to tie the 12V systems together. 

From: "Gary Graunke" <gary at whitecape.org> 
To: gburket at peak.org 
Cc: "Corvallis EV CLub" <caevlist at caevclub.org> 
Sent: Wednesday, August 1, 2018 9:23:29 AM 
Subject: RE: [Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM 

I have the common absorption DC/AC/LP 3-way refrigerator. It draws about 14 A on DC when I measured it, but I don’t recall the temperature condition (just starting to cool vs maintaining cool temperature). There is a 20 A fuse in the fuse panel for the refrigerator. 

Not sure what to do about the plug. It does have some contacts that seem a bit corroded, whether through rust or heating from drawing lots of current. 

Perhaps duct tape it in when I plug in to keep the dirt out? The X does have a latching spring cover that holds it in. The trailer plug is the one thing that is hard to prevent problems with, even with fuses right at the end of the cable. 

I’m pretty sure attaching all the ground wires to the household ground bus will make the connections secure, but the wires can still break. They are stranded, so should be best one can do. 

I’m thinking of putting in relays (and back EMF diodes in parallel with the coils, of course) where the fuses are now to isolate the area where a short can affect the vehicle to the trailer plug and cable. It does change the load from resistive to inductive. 

Gary 

From: gburket at peak.org [mailto:gburket at peak.org] 
Sent: Wednesday, August 1, 2018 9:06 AM 
To: Gary Graunke 
Cc: Corvallis EV CLub 
Subject: Re: [Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM 

Hi Gary, 

What type of frig do you have and what is its normal current draw? The absorption cycle (ammonia and H^2 ) friges can draw a large 20-30 amp load in the 12V mode and quickly drain a typical RV house battery. The blown 30amp fuse on the aux 12V line from the tow vehicle might be a clue here. I don't know what your trailer has, but the typical trailer tongue plugs are kind of crude and operate in a pretty tough environment. A lot of movement of the plug along with vibration, road grime, and water can cause arcing and shorting problems in the plug that can mess up trailer and tow vehicle electronics. That said, most of the problems I see with trailer 12V wiring systems are related to bad grounding . 

Glenn 

From: "Gary Graunke" <gary at whitecape.org> 
To: "Kirk Swaney" <kirk at shiftev.com>, "Corvallis EV CLub" <caevlist at caevclub.org> 
Sent: Tuesday, July 31, 2018 10:05:06 PM 
Subject: Re: [Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM 

I could use a bit of the brain power in the group to help solve a mystery. Tesla has replaced a hardware module twice now, and the next time will cost me $500. (Plus we all want to solve this so I can continue camping with model X and trailer and they don’t have any warranty issues). 

I towed my trailer with the refrigerator on to Roseburg (on purpose, I thought I had 200AH of Calb cells connected in parallel, but the wire was too thin). By the time I got to Springfield to charge, the trailer battery was dead. The Calb cells were only somewhat discharged. But the left turn signal/brake light was on constantly, even while the car was charging and not “on” (later I found it had 13V even when the car was off). 

At Roseburg, plugged into shore power, I noticed my current draw was 9A at 120VAC. Turning off all other current drains, I opened up the trailer battery box. It was very hot (and very dead—6V). I pulled the fuses connecting the dead battery. 

I had to come back to Portland for the EV Roadmap conference, but left my wife and trailer in Roseburg—I would return the evening after the conference and continue the campout. When I started home, it went into blue (normal) trailer mode, even though no trailer was attached! Turning it off from the touch screen, it went still displayed an orange trailer mode, but auto-steer worked. 

Tesla replace the part in amazingly short time while I attended the last day of the conference, and I headed back to Roseburg on schedule. 

At the end of the first campout, I towed the trailer a short distance to a second campout in Sutherlin, about 11 miles away. No problems. 

Getting ready to return home from Sutherlin, we checked the trailer signals—all were working. However, by the time we got to Springfield to charge, it had failed again! This time the fuses were pulled on the battery (and the refrigerator was OFF). 

With the battery disconnected, I connected a lab supply to each of the six non-ground trailer connections to measure the current it draws at 12.7 V. 

The tail and running lights drew .53 A, Right turn/stop light .16 A, backup lights 0 (no backup lights—no connection), trailer brakes >3.15 A, Left turn/stop light .2 A, and the aux draws .29 A. Chassis ground to plug ground measured .1 ohms with the multimeter. With the dead battery installed, the aux started at .16A and increased steadily (odd, it started at .16 with the dead battery installed). 

I took the trailer and model X into Tesla last week early Monday morning. They didn’t have the part, and it finally came late Thursday. 

On Monday they had me replace the dead battery with a good 17AH AGM 12V battery I brought. By Friday, it was down to 7 V, so the technician charged it, and they asked me to bring a new battery. (I was going to replace it with the CALB cells, but bought lead to keep things simple). 

They fixed the model X on Friday morning and also replaced a blown 30A fuse on the aux line to the trailer that provides 12V. They and wanted to keep both to continue investigating, but I insisted that I had a camping commitment for the weekend. I connected a brand new 80A 12V trailer battery and drove it home. Since it made it a short distance from Roseburg to Sutherlin in the past without breaking, I later changed my mind and left the trailer at home. So far, both model X and trailer are still working, but I only drove it 19 miles home from the shop. 

Monday I redid the low voltage wiring. It was a single glob of wire and wire nuts all wrapped in electrical tape. I connected all the grounds to a home ground bus bar, a split bolt for the +12V, connected the 6 hot tow vehicle harness wires to a terminal strip, and the wires to which they were connected to a second terminal strip, and put zip lines around each of the remaining wire nuts and taped them individually. ATC fuses now connect the two terminal strips. 

I’ve installed 3A fuses for the turn lights, 5A for the tail/running lights, 30 A for the brakes, and 20A for the aux 12V. 

My neighbor suggested that the .29 A phantom load is too high, and may be the indicator of an intermittent wiring fault. I’ll try to trace it tomorrow morning. 

So that’s it. I’d still like to understand what the trailer is doing after 1.5 years of happy camping to kill the Tesla part. Was it the dead battery (the Tesla tech says the aux circuit is separate from the dying part)? Or are both victims of the same common cause? 

Gary 

From: caevlist-bounces at rdrop.com [mailto:caevlist-bounces at rdrop.com] On Behalf Of Kirk Swaney - SHIFT Electric Vehicles LLC 
Sent: Tuesday, July 31, 2018 6:22 PM 
To: Corvallis EV CLub 
Subject: [Caevlist] EV gathering tomorrow, Wed Aug 1st @ 7PM 

It's time for the monthly Corvallis-Area Electric Vehicle gathering. Newcomers & friends are always welcome. 

Meeting location for this month is Otmar's shop, the big red garage with white doors. 
2255 SE Crystal Lake Dr 
Corvallis, OR 97333 

If you'd like to let us know beforehand about a project you'd like to share, something interesting you're bringing, or any help that you need, feel free to Reply-to-all and tell us about it! 

If you have an unusual EV, please park inside the shop if there is room for show and tell. 

Plenty of overflow parking for the non-electric vehicles is available in the main driveway and the next two driveways to the south. 

Charging is available: 115V, 14-50's and J1772 at 32A. Also two Tesla wall connectors. 

Hope to see you there! 

Kirk Swaney 

Virus-free. www.avast.com 

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