Strange HV battery problem?

So Ive got two identical 2005 pri, the one im concerned about has a newer toyota HV battery in it. Problem is , the ICE is running way too frequently and the MFD shows the HV battery drains even when the brake is fully engaged. Such that i have to put the car in park at red lights or itll just keep draining.

Im thinking of switching the HV battery for the reconditioned one I built in my other prius because im worried this problem prius might hurt my newer toyota battery, does this seem reasonable?

I have no reason to think the fans or ventilation is blocked but if anyone has any notes on determining that Im all ears. I also havent read the ABS codes in a while but i think it was some sensor , still not an explaination for the strange HV buisness. Sometimes the car throws p0420, if i havent disconnect the 12 volt in a long time but all prius with 1000000 miles do that, bad cat, oh well sorry envirnoment.

A little info on this prius (was abandoned):
I should mention that when i got the car the HV battery inside it had actually exploded and I never did determine how the hell that was even possible. The 12 volt wiring had also been cut out for some reason and the brake actuator?/accumulator? had to be replaced. Shortly after replacing it, i hit a bump and the ABS , !, and parking brake lights came back on and are still on to this day. The brakes seem a little weaker since this but still alot better than having zero brakes at all like when i first got it (yes i drove it to the shop with no brakes). I rigged up a wiring for the 12 volt and just have a large deep cycle strapped down in the trunk. I used to have to disconnect it several times to get the dash lights on but that problem seems to have stopped with a better ground connection.

Pardon my spelling, i think my point gets across regardless, Thanks in advance for yall's help.

 

Oh man trust me i know, i got a OBD II interface (wifi) and usb but techstream isnt compatible with my mac/iphone and Dr prius is but i just cant get it to work even after paying for it. I can get some info from an app called Car Scanner but not detailed HV battery info. Thing is neither of my batteries are in great shape. One i rebuilt, ones from toyota but getting stressed by something else in the car. Have you ever heard of one blowing up? that piece of the puzzle scares me.

Im thinking of installing 2 12 volt vans down there just to make sure theres good airflow but that sounds crazy. but I dont think ive ever heard the fan in the backseat come on in the problem car. The VSC ABS ! parking brake codes also cant be read through that scanner too , correct? If i recall someone once blamed it on a wheel ABS sensor (but he couldve just been trying to cover for a shotty accumulator/actuator/brake job too). I guess ill get out the wires and read some blinkys.

The MFD showing the battery draining while at a complete stop I KNOW is not a typical prus behavior as they always turn off the engine and stop draining from battery when at a complete stop with your foot on the brake. When you lift your foot off the brake a little, then it is supposed to drain.....so could something not be sensing my braking ? In fact, as soon as you put your foot on the gas (of the problem prius), the ICE kicks in immediately as opposed to waiting till a certain acceleration level. or could something be pulling electrical power excessivley even at a stop? Oddly enough , in my other prius, thats operating normally-ish, I have a 12 volt at 10.1 volts and a subwoofer and amp setup (probably what killed my 12 volt) but it doesnt display this battery draining at a stop thing, just needs two button pushes to start ( i know im going to replace the 12 volt right now actually). But the problem prius has a brand new 12 volt (all be it rigged up to me fancy wiring replacement for the one cut out).

 

If you could point me to a copy of techstream or something compatible with a mac ( i could even dig up an old windows laptop im sure) but from what ive seen its insanely complicated to use and im just not a technology guy. Im more of a jump start your prius with a drill battery kinda guy.....or is it the OBD II interface the problem? does the mini vlc specifically do something more? Thanks for yalls help again. These 2 little pri saved my life and got me the hell out of california and back to Colorado, so I want to keep them around a while. Nobody thought they would make it honestly.

 

I guess you can never provide enough detail, right. I recently learned those colors of the bars means something, on my rebuilt (and maybe newer toyota battery) they go from blue down to 1 bar now sometimes, and then i just coast and it charges back to full green bars suspiciously fast. This is a sign of a bad cell , isnt it. I know both batteries were stressed hard by crossing the rockies in the weather we did, i always pulled over at two bars to let it recharge a bit. But ive never seen just one bar till recently.

 

lol no i just meant it has a ton of miles. almost 400,000 i think

 

This is an interesting thing i hadnt yet considered. You mean thats why the HV battery is always draining even when stopped? Because the 12 volt system i have in there is NOT stock for sure (pics to come)

 

But my other prius has a bad 12 volt in it (hold charge at around 10.5 volts) and it doesnt display this behavior

 

I see, i have a basic code reader, only gives me the codes when a check engine light is on, which is always p0420, bad cat or maybe loose sensor (ive never changed it). ill get some windows / android action going here but am i correct in understanding this basic OBD II code reader is basically useless? So I need a prius specific code reader, right? The mini vlc? or....which? Which is totally worth it to me, considering Ive gone this far with one of my priuses. Sorry, Pri*. I know, its dirty but sometimes you gotta clean off your bench seat. in a prius.

 

Also...could using a regular wet beep cycle marine battery affect anything? Its brand new, holds good charge. And prius puts out 14.1 ready as usual.i think.

 

Welp, in my truest fashion, i took a kind of non issue and screwed it up significantly more. Now im talking about my OTHER prius. I had to replace the 12 volt , so while i was doing this i decided to poke around the H V battery. (Previously i mentioned wanting to switch the batteries but i decided the ABS system is the real root of the issue, after driving her for a few days.) sooo while i was switching the 12 volt anyway I wanted to make sure the fan wasnt clogged with dog hair, multimeter around the battery (even though i know this doesnt show the full picture of battery health)....I admit i did this opening and disconnecting then reconnecting in the dark at 3 am. When i went to start the car, it didnt want to switch into ready, it displayed the red triangle, and problem on the MFD. I could hear the relays open, it briefly said ready, then ready would dissappear. I did this 3 times, hearing a distinct electrical short noise the last time. Between each attempt I was pulling and putting back the orange service plug as i know this is a common cause for a brief red triangle....i reopened and found the main orange cables were not sinched down well at all. The car then started normally into ready, but the red triangle hasnt gone away, the battery discharged and charged rather quickly (but that was the issue i was originally investigating).

Read the codes and its P0A0D and P3000, the orange service plug doesnt seem to sit right but for the life of me i cant get it to go in , and i have 2 spare orange service plugs. HELP!