Ben Nelson's Electro-Metro Build thread

[Patrick]

How many amps and what voltage are you charging at?

[bennelson]

The current battery configuration is 72 volts.
The charger is adjustable - you set the peak amperage. That's the amperage the charger starts off at when you plug it in and then the amperage drops as the voltage rises during the charging cycle.

The charger can output up to 20 amps. I usually would have it set to around 10 or so, as that doesn't pop 15-amp residential breakers.

[bennelson]

I also just received my no auto registration in the mail. It lists the NEW, CUSTOM license plate - and I got the one I wanted!

The plates themselves may take "4 to 6 weeks", which is interesting, because I think that means that legally, I am running around with the wrong plates now!

Oh well, just keep the copy of the request for custom plates, the old and the new registrations, and don't get any more speeding tickets!

[Angmaar]

Wow! I just read this whole thread, all 1.4K posts, it was awesome. I now wish I had a few thousand dollars for an EV conversion. Maybe an "E Wheel" type 5th wheel thing will suffice.

[bennelson]

Man, I don't think I have even read the whole thing....

[bennelson]

One of the things that I HAVE found to be problematic in this car is that it runs on used batteries.

All of the batteries are of slightly different age and condition, although they are all the same size and chemistry.

When batteries are in series, the worst one limits the rest. When recharging, the worst battery either doesn't get charged all the way, or it does and the others get OVERcharged.

When parked, I can always use a volt meter to measure the batteries individually, but I really need to see what they are doing when the batteries are under load. That means seeing what all the batteries are doing at the same time, WHILE DRIVING.

A while back, I mentioned this to my friend Tom, who is an electronics guy, and showed him photos of an LED bar used for battery monitoring.

Tom has been working on the his version of LED battery monitors. Each board has 4 bars of 10 LEDs, and can monitor four batteries. The LEDs light up from bottom to top as a mini bar graph. The more voltage the battery has, the more LEDs that light up.

Last night, I assembled two boards, a switch, some plexiglass, and the wireharnesses to go to the batteries. The finished device can monitor up to 8 batteries. (I have 6 in my car right now)

Here it is:


I'm going to test out the monitor, see if there are any other features we want to add. In the future we might even sell the battery monitors as kits or pre-assembled.

[adamj12b]

Ben,

Thats really cool.

One thing you should consider, is when you install that, all the wires from the batteries to the board should be the same size and same length. This way they will all have equal voltage drop.

-Adam

[bennelson]

I did ask Tom about that.

All the wires are the same diameter.

As to length, apparently, voltage drop is dependent on amperage draw. This device pulls almost no amperage. Thus, if one wire is a little different length than another, it really shouldn't matter.

[chrishil]

I'll wait for your threads involving electric vehicles and at the same time if ever, hybrid cars.

[exrdega]

Originally Posted by ldjessee00

Some suggestions:

MY EV
MY E CAR

EV GO GO
GO EV GO
GO GO EV

DIY EV
EV DIY

I prefer the last two for you Ben.

LDJ

how about NOFNGAS