Ben Nelson's Electro-Metro Build thread

[bennelson]

It looks like a television designed by Dr. Suess!


I ran the car through the carwash today. I couldn't resist shooting video, but I only had my digital still camera with (which has a motion record feature!)

http://www.youtube.com/watch?v=5VlIIfyS1t8

[Daox]

I take it you went through with the bellypan installed?

[bennelson]

Nope! Pulled off the bellypan to work on the motor mount - haven't put it back in yet.

I unplugged the charger this morning and then let the batteries sit for a while.

I measured the voltage of each battery.
These are the voltages of the charged, rested, non-heated batteries - temperature is 15℉ outside. Batteries 1-4 are in the truck/hatch, and batteries 5-6 are under the hood, where the radiator used to be.

I then drove 3.9 miles, and measured the voltage again.

Here is the battery number, then the voltage while charged and rested, then the voltage right after the 4 mile ride. The third column is what the voltage was about an hour and a half later.

1 12.93 V 12.48 V 12.68 V
2 12.86 V 12.38 V 12.60 V
3 12.74 V 12.19 V 12.43 V
4 12.77 V 12.18 V 12.45 V
5 12.89 V 12.32 V 12.64 V
6 13.01 V 12.51 V 12.78 V



Note that the voltages I listed are when the car isn't moving. (The batteries are NOT under load!) The batteries drop in voltage real fast while driving, especially accelerating or going uphill.

Looks like batteries 3 and 4 aren't doing as well. Maybe I need to individually charge these two after my next charge cycle.

[TestDrive]

Originally Posted by bennelson

Later, I will add the voltage of the batteries after they have sat for an hour or so.

Might it also be useful to check voltages after a longer rest period - say 15-24 hrs???

[bennelson]

Do you mean to say to check them 24 hours after being fully charged and the charger turned off or drive the car, park it, and check the voltage 24 hours after that?

I don't want my batteries sitting around discharged for too long, but I suppose 24 hours once won't hurt them.

[Intrigued]

From what I'm hearing, a couple of hours of waiting is okay for checking voltage after a charge.

Also, shouldn't those be at something like 13.2 volts charged??? Maybe you're not getting them fully charged???

[bennelson]

The charger I am using is a "gentle charger".

These are gel-cell batteries. The insides of them are something like Jello. They need be be charged at a lower voltage than other battery types.

Flooded lead-acid batteries can be charged at a high voltage. They will just convert some of the water/acid into hydrogen and blow it off. You then have to replace it with some distilled water.

The gel-cells are sealed. If you charge them at a high voltage, they can get voids in the Jello and wreck them.

The big advantage to these batteries are that I don't have to worry about them leaking, tipping over, spewing hydrogen gas, etc.

Modern SLAs & AGM batteries have all those same advantages while worrying a lot less about charging voltage. Gel-cells aren't used much any more. In fact, I got such a good deal on them because they were being replaced by AGM batteries in their application.

So, yeah, my batteries are always going to read a little lower because of their style and how they are charged.

[Intrigued]

Oh, yeah, I remember Gel-cells... now that you mention them...

[Christ]

Maybe a full cycle will help the batteries stabilize a bit? I mean drain them until they won't drain anymore, and then use a trickle charger to bring them back up to full voltage... might take quite awhile, but if you think it's worth it to try, it's worked for all my dad's car batteries.

*He's been using the same 1000 Amp (850CCA) battery in all his cars for about 15 years now... that ^^^ is how he keeps it fresh... once a year. It's a lead acid battery though.

[bennelson]

I finally got my emissions sticker in the mail today!

All I have to do is stick that on my rear license plate and it is officially a 100% street legal electric car!