Greener Pastures

It has rained almost non-stop this week, taking away any real chance I have had to work or even drive the EV. I did take the time to think through my battery upgrade and contact the local Sam's Club for some specs. I need to physically inspect the batteries to be sure, but the specs they gave me matched the US 8VGC to the letter, which is my current battery of choice. I have the price of the pack and next I have to check prices on the material for the new battery rack and to find a way to weld it.

I am giving myself until the end of April to get the new batteries and rack built. I am first going to visit Sam's Club, check out the batteries and get measurements. Then I will have my rack built before I even purchase the batteries.

Until then I will continue driving the EV around town and continue enjoying driving gas free.

The Culprit?

After swapping the PakTrakr remotes and finding similar readings as I was getting earlier, I decided to do some random thinking. I went for a 9 mile run, and found that battery 2 was again getting lower under load, compared to the other batteries, so I went home to charge up. After 3 hours, I went to browse the PakTrakr screen and found decent charging voltages, but my remote said the batteries were at 104F! The remote was sitting on the cable that goes from battery 1 to 2 and it was hot, even after 3 hours of charging and not high amp cruising.

Stunned, I took out the DMM and found that the cable in question had 0.9 mV flowing through it at 2 AMPs charging current, while all the other cables were at 0.1mV! It had 9x the resistance!

I have replaced the cable with another (I've got a stash of spares) and hooked up the charging and it was a nice 0.1mV like the rest. This could be the reason why my PakTrakr has found battery 1 and 2 lower than others because part of the signals use that cable, and that cable has a lot of resistance when it gets hot.

Never Ending Thinking

I haven't driven my EV in the past few days because I have been booked solid with school projects. This evening I finished up a few of them, then did my usual EV web surfing of forums, blogs and such. I was reading another EV'ers blog and they mentioned having to replace their PakTrakr remote because it was giving errors, false failures and wrong voltages.

I have been under the impression that two of my batteries are bad, or lower than the others according to my PakTrakr. I have actually never measured the batteries with a volt meter, but decided to and found they were all equal according to my digital volt meter, but not according to my PakTrakr. So my idea is that I am going to swap my two remotes with each other and do a test drive for 12-13 miles and see if I get the same low battery warning I was getting before, or see if I get the warnings on other batteries.

It's 9:30 at night and I would run out right now and switch the remotes, but it's pouring rain. So I have a plan for tomorrow to look forward too.

More Range!

I spent most of this week driving my EV, messing with batteries and figure out what I need to do. I have decided I need larger capacity batteries. My current batteries do very well until I reach 50% capacity, then they drop and sag a lot, so I usually stop driving at that point, or about 12.5 miles. My Zilla makes it very easy to pull massive amounts of AMPs for accelerating, and my commute has changed a little, so I really need more range, more like 25-30 miles for a lot of more things I have been doing recently, like visiting relatives and not having the time to fully charge, etc. Also, half the roads I took to school used to be 25 MPH due to construction, but are now 45 MPH, and maintaining that takes a toll on my range, but the Zilla happily gives the power while my current batteries cry.

What I did this week was do research of the 8 Volt Golf Cart batteries, from US Battery, Trojan, Exide, etc to see what options are out there. I am now looking at Sam's Club and Costco as they sell these batteries for excellent prices. I have also asked fellow EV'ers who use these batteries, and they consistently get 25-35 miles per charge from the 8VGC batteries. They are usually 170 Ah, a huge step up from my current 125 AH, and they do not suffer from lots of sag past 50% mark like most 12v batteries do. I have designed a new battery rack on paper, and I will check out material pricing this week on it, and also get battery prices from the local Sam's Club and Costco.

Now this means I have to make new battery racks for the 8VGC, but that will happen after I confirm the size and that I have the money for the pack and the tray. For now, my EV is great for all the around town activities, and it may get a little better with more cycles on the pack, but my normal driving activities require more range, and at higher speeds than I am used to driving.

Warm Weather Fun

I have collected so much data and done so more research on my batteries that I could write a paper. Wait, I am....

It was over 65F today and I couldn't resist driving my EV, so this morning I hooked up my laptop and drove 12.9 miles and didn't get a single low battery warning! I have also found that the extension cable I use to charge can't handle anymore than 10 AMPs continuously, so the end that plugs into my EV kinda burned out. I usually charge at 12.5 AMPs when I am at home and the connections end has been warm and slowly cooking itself. I have been using a 50 ft 12/3 cable that has a rating of 15 AMPs, but clearly it can't handle it, so I got my Dad's heavy duty 10/3 50 ft cable and it stay cold giving out 12.5 AMPs!

Here is my EV with the huge cord plugged in. It barely fits into the socket on the EV, but does a nice job. However, I still needed to replace my bad cable, so I hopped into my EV this afternoon and drove down to the hardware store and got it exchanged. I usually refrain from going any where in my ICE because it cost me gas money, but with my EV fully functioning I didn't think twice. My only concern was what music to listen too. :)

I now have two power cables, the big yellow one that sits at home and my smaller red one that now lives in the EV. This actually works well for me because now I don't have to fish out the cable from the basement every time I want to drive the EV somewhere and charge it.

Zoom Zoom

I have fixed my issue with my batteries heaters, I just replaced the +5v regulator with one that works from -40C to 90C. My batteries now maintain a solid 76F, and they only cycle on for 30 minutes every 4-5 hours at night, and don't turn on at all during the sunny days.

My Zilla has sprung an unexpected problem, though. If I am cruising, then decide to go full throttle (100% duty cycle) the Zilla get's a fault and shuts down. Apparently this is a problem that was found recently with low voltage EVs and the Zilla, and there is a fix that I should be getting in the coming week or so. For now, all I have to do it set my Motor Voltage less than my Battery Voltage and it's all good because the controller will never hit 100% duty cycle that way. And during my drive today it worked great, and I suffered no performance decrease at all.

I have been slowly working my batteries into existence. I have been using test routes, ranging from 4.0 miles and increasing that and now I go for 12 miles at a time. I have found that two batteries are much lower than the others under load, but I have been working on them. What is happening is two batteries would get to the point when they would go under 10 volts under heavy load, at the 3.8 mile mark. Then I did some battery charging, equalizing and magic and they didn't complain until 8.8 miles, then 10 miles, now 12.2 miles. I believe they need to be broken in slowly, so I have been adjusting my driving to help out. Each drive gets better and better, and I am guessing that I should have my full range in a week or so of these break in drives.

According to EV America, letting the flooded batteries rest for a weekend affects their performance, and if they rest for a week you have to break them in again slowly.