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Old 02-03-2011, 09:28 PM   #53 (permalink)
Artric
Hypermiler Extraordinaire
 
Join Date: Oct 2008
Location: Deltona, FL
Posts: 22

Insight - '01 Honda Insight
90 day: 90.11 mpg (US)
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Quote:
Originally Posted by discovery View Post
At what Voltage is set the charger? Is it at 144V or above 144V? How difficult is to build one?
Assuming you're talking about a G1 Insight or G1 Civic Hybrid, 144v is only the nominal voltage. When your pack is at that level, you're pretty much empty (in terms of what the car will let you use). A full battery is usually in the high 160's to low 170's (depending on condition and temperature).

The chargers have a variable set point which marks the highest that it will charge to. I usually set it around 177, because that's higher than I've seen a pack go. It doesn't charge at this rate, but rather the current voltage of the battery. A constant current/variable voltage power supply is used to give it a "swing" of 39v. Therefore, at a max of 177, it will charge as low as 138v (which is actually 1.5v higher than what is given to the battery, as that is lost from diodes).

It's really not too difficult to put together. I just depends on how fancy you want to get with it. For me, that entails finding dead power supplies, gutting the cases, measuring, drilling, testing fans, etc. They work great for me as I can sometimes get them for free, or just a few bucks, they're usually just the right size, and they include a standard AC power outlet, fan, and sometimes a power switch.

But you can be as simple as affixing them to a piece of wood, like you see here: MIMA Honda Insight Modified Integrated Motor Assist - Building a hybrid car grid charger

Wiring is pretty simple - you run AC power to three 48v power supplies (Mean Well RS-25-48), one 12v power supply (Mean Well RS-25-12) and one 350ma constant current power supply (LPC-20-350), with a fuse for protection (use 10A, on the following diagram it says 1A, which will blow constantly). Then you wire all of the power supplies, except for the 12v one, in series, and you've got your two outputs for charging - just set the max voltage using a screwdriver on the side of the units. The 12v is there to power your pack fan and anything else you might want to use it for.

Those are four wires you need to get from the charger into the battery box and connected to the battery and fan. For the fan, you just need to splice into its power wires. For the battery, you need to connect to the top negative connection on the battery with a ring terminal, and lower down on the side of the battery (at the precharge resistor) for positive, using a piggyback spade connector. In addition, you'll need to use diodes here to make sure that charge only flows into the battery and not back out to you or the power supplies. You don't want to get shocked! You also need to put a small DC fuse in place on the positive side (in line with the diode, so you'll need to solder, as well as crimp for the connections).

That would give you a direct connection, but if you want to be more fancy, you can use molex connectors, bullet connectors or a number of other options.

You can see the diagram for the grid charger with pictures here: MIMA Honda Insight Modified Integrated Motor Assist - Grid charger/Balancer 1

And you can see info on the components and how I install wiring here from my walkthrough: 7 - Power Off | Flickr - Photo Sharing!

Good luck!
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