HV Battery Drain

**Tideland Prius** · 04-30-2005, 06:16 PM

Ok, some time last year I posted a question regarding the battery dropping a bar overnight. Now I can confirm this. I was parked in a parking lot waiting for my bro. The battery was at 5 bars, then dropped to 4 as I waited. When it did so, I decided to shut off the car instead of letting it keep discharging. When I started it up later (5? 10mins? later), the battery was at 3 bars.

What gives?

Frank Hudon · 04-30-2005, 07:00 PM

it was probably at the toggle point on voltage and starting it was just enough draw on the battery to pull it down another bar. On the 2k3 the best I can tell for starting current draw is about 34 amps. That has been the highest number I've seen on the MiniScanner. The 2k4-5 with the larger MG1 and a lower battery voltage will probably be higher but at this point in time the only way to find out is with the THHT.

xevious · 04-30-2005, 09:46 PM

NiMH batteries are notorious for their terribly high self-discharge rates. The traction battery could easily loose 10% or more of its charge in a week just by lounging around in your trunk. 10% of full charge range is roughly 25% of the useable charge range. Rough numbers but you get the point...

...and what Frank said. Just sitting still in IG-ON mode, there is a significant draw on the traction battery, especially if blowers, heaters, A/C, headlamps, or audio is on.

All in all, I'd say that your experience merits a tick in the "normal" box.

04-30-2005, 06:16 PM	#1
Tideland Prius Super Moderator Join Date: Oct 2004 Location: Canada Posts: 13,920 My Car: 2005 Prius Package: B Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 11	HV Battery Drain Ok, some time last year I posted a question regarding the battery dropping a bar overnight. Now I can confirm this. I was parked in a parking lot waiting for my bro. The battery was at 5 bars, then dropped to 4 as I waited. When it did so, I decided to shut off the car instead of letting it keep discharging. When I started it up later (5? 10mins? later), the battery was at 3 bars. What gives?

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04-30-2005, 07:00 PM	#2
Frank Hudon Senior Member Join Date: Jan 2004 Posts: 4,144 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	it was probably at the toggle point on voltage and starting it was just enough draw on the battery to pull it down another bar. On the 2k3 the best I can tell for starting current draw is about 34 amps. That has been the highest number I've seen on the MiniScanner. The 2k4-5 with the larger MG1 and a lower battery voltage will probably be higher but at this point in time the only way to find out is with the THHT.

04-30-2005, 09:46 PM	#3
xevious Join Date: Jan 2004 Location: Oregon Posts: 187 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	NiMH batteries are notorious for their terribly high self-discharge rates. The traction battery could easily loose 10% or more of its charge in a week just by lounging around in your trunk. 10% of full charge range is roughly 25% of the useable charge range. Rough numbers but you get the point... ...and what Frank said. Just sitting still in IG-ON mode, there is a significant draw on the traction battery, especially if blowers, heaters, A/C, headlamps, or audio is on. All in all, I'd say that your experience merits a tick in the "normal" box.