How to determine actual HV battery voltage?

Discussion in 'Generation 1 Prius Discussion' started by ronlewis, Oct 2, 2019.

  1. ronlewis

    ronlewis Member

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    As I mention in another post, this latest car starts and runs, but my ScanGauge displays 0v and 9% state of charge, which makes no sense. Is there any way to confirm actual voltage without taking the battery out of the car? I pulled the orange plug and tried touching my voltmeter to each of the two contacts inside that connection, but didn't get much voltage. How about measuring at the two output terminals, where the orange cables connect going to the front of the car? I always check there when taking the battery out of the car, after removing the plug and letting the voltage drain. If I leave the plug in can I measure there without killing myself?
     
  2. gothstone

    gothstone Junior Member

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    The orange plug just breaks one side (neg I think) of the connection half way through the pack, so won't show voltage. The output terminals won't show anything unless main relay is engaged at which point there is current flow and I would get WAY more nervous. If you look at the forward end of the main relay you will see where 2 orange cables from the modules bolt to the relay set itself. That's where I'm measuring from.
     
  3. ronlewis

    ronlewis Member

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    Well, darn it, that requires that I remove the battery from the car. At that point, a few more bolts and I could measure each module individually. I think I'm going that route. If the battery is good, I'll use it to fix my other car and worry about a battery for this one after I get the body work fixed.
     
  4. ronlewis

    ronlewis Member

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    UPDATE: removed the battery and every module tests at least 7.2v. Before taking it out, the dash gauge was at one bar, so I assume those will all charge up a little more once I drive it.

    Boy, I'm getting tired of lifting the batteries in and out of these cars. BTW, this one has been removed before. Bolts were lose and one holding the fan to the case was missing. Combined with the three labels (assuming that's a valid indicator) I expect this is at worst a rebuilt and at best a new Toyota replacement. I know the rebuild I got from Best Hybrid had their name on the labels, this one only has Toyota's name. Anyone know how long Toyota warranties their replacement batteries and whether the warranty transfers with the car?

    At this point, I've gotten one good battery from this wrecked car I bought, which breaks me even on its cost. It also has great tires, a great spare, a working touchscreen, and a running engine, so I think I did good.
     
  5. Josey

    Josey New Member

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    Have you heard of the Dr. Prius app? It's free for the Gen 1s because it doesn't have full capabilities. But it will tell you the total battery voltage along with individual module voltages. All you need is a cheap bluetooth OBD2 plugin to communicate with the app. I bought this one and it works fine:


    It provides live data and will record it and you can then play with the data after the fact. (Saved in .csv format as I recall).
     
  6. ronlewis

    ronlewis Member

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    Hadn't heard of that. I already have the Bluetooth reader. Is it an Android app?
     
  7. Josey

    Josey New Member

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    I'm using it on an android. I find it to be pretty awesome.
     
  8. ronlewis

    ronlewis Member

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    Cool, I'll check it out.
     
  9. Brian in Tucson

    Brian in Tucson Active Member

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    If all you want is to get the overall voltage, take a look at the installation instructions for the Prolong reconditioner. ) The old discharger (the one that used light bulbs) also used a cheap multimeter like the ones Harbor Freight gives away. Gotta be really careful how you accomplish a harness, 'because it will give you a nasty jolt. But it could be done.
     
  10. Brian in Tucson

    Brian in Tucson Active Member

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    BTW, Ron, there's a nice non running 03 on CL in Tucson for a grand. OBO. I've sworn off any new projects for now. No room and no energy. Right up your alley? You could turn your collection into a parts source for the other inmates of this forum.
     
  11. ronlewis

    ronlewis Member

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    Thanks, Brian. I'll definitely work with anyone who needs parts, once I get all my cars fixed so I know what I'll need. And I'm 99% there. Actually, I need a battery module right now myself, if anyone has a good one for sale.

    Honestly, I've paid less than $1000 for all of mine, even the running ones. That'd be a hard price to recoup when these cars are selling for $2500-$3500. Just buying a battery would make it a break even, without even adding the labor to install. Any more /parts/labor, and it's a loss. As is, I have to put the hard sell on the ones I got to make money. But thanks for watching out. I also need to move a couple of I have just to clear room in the driveway. I have two more waiting to be worked on now.
     
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  12. Brian in Tucson

    Brian in Tucson Active Member

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    Yeah, too rich for me. I was thinking (not seriously) of offering $400. That's what I paid for my last non running 02. It turned out to be a gem.

    The semi crash of the Gen 1 prices has made me move on to Gen 2's. There's a Gen 2 on CL, an 08. For $2000. OBO, I bet. Only thing is a salvage title and it would require inspection by the DMV. 2008 Gen II Package 6 Prius SALVAGE TITLE! - cars & trucks - by owner - vehicle automotive sale But relatively low mileage and the body damage isn't too bad.

    There's also an 03 that a guy is asking $3995 for. I want some of the drugs he's on. :D
     
  13. ronlewis

    ronlewis Member

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    Yeah, I haven't tried to actually sell any of mine yet, lol. Or at least not for several years. That's when i sold my original that I bought in '01, IIRC, for less than $2500.

    These cars are just victims of history, kinda like the way scammers were inflating real estate prices, but in reverse. They'd buy a property and execute several changes in ownership (paperwork transactions only), each time inflating the price, before then dumping it on some unsuspecting stooge who, like the banks, took the prior transactions at face value and based their latest valuation on those sales.

    Because Toyota tried to gouge owners with exaggerated prices for replacement batteries, owners dumped the cars as worthless, and now we're stuck with lots of historical valuations of these cars as worthless. I just think there's a price point where people have to admit that they're worth it compared to what else they can buy for that price. I'm driving this beautiful '03; runs like a top, cleaner than most cars, with a new battery, at a cost of less than $3000??? It's crazy. Look online at what else you get for that price - nothing but crap. You can literally drive these into the ground and throw them away at that price and feel great about the value received.
     
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