The impossible just happened?

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softdown
softdown Solar Expert Posts: 3,824 ✭✭✭✭
in In the Weeds--Member's Choice #1
Trusty Explorer failed to start for the first time - ever. Not too worry, just empty out remnants of the past years hurricane of events from the trusty Prius. Starts and runs perfectly as always. Drive 20 miles and shop for 20 minutes. Return to Prius.

Will not start. Yellow triangle of death is blinking intermittently. Rear cargo door is very hard to get to respond to key fob. Soon will not respond to key fob at all. Bad because this accesses the starter battery.

Google it. #1 response is dead key fob battery. I consider this possible because key fob communication is not always ideal in colder weather. Buy $7.50 button lithium battery from ACE and hope for luck. Now there is NO response from the Prius to anything at all. Must the dealership program the key fob when the battery is changed?

I'm at a complete loss now. The situation went from dire to gruesome. Now I have a key fob that does not communicate with the Prius. Then I decide to check the starter battery voltage since Harbor Freight is right there and sell voltmeters for $7. Lo and behold the starter battery voltage is 6.5 volts. This explains everything.

Big R is across the street. I buy a group 51 battery and try to install it. The Prius uses pencil battery posts. But I have jumper cables and that allows the Big R battery to jump the Prius battery.

Make it 20 miles home and check the Prius battery. Shows 12.9 volts and 505 CCA and 5.5 resistance. The resistance is high but it still tests as a good battery. The CCA are still up to new battery specs after 3 years.

This was not possible but it happened. How did a seemingly normal battery show 6.5 volts after being parked for 20 minutes? How did it return to 12.9 volts and 505 CCA after a 20 mile drive? 505 CCA is a good number for a little 28 pound Prius battery.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    edited January 2022 #2
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    Prius starter batteries have recently jumped fro $180 to $252 at Amaz. Extortion for a 28 pound starter battery. I buy adapter for pencil battery posts and plan to use a Costco Interstate battery that recently jumped from $70 to $105. What is going on? THIS IS NOT 5 OR 6 OR 7% INFLATION. This is very extreme inflation.

    And Big R struggled to accept a battery that was bought 10 minutes earlier. I had explained that it might not fit and confirmed I could return it. But it still took mgmt approval and a struggle. I fear Big R is in trouble. They had a poor battery selection and some were dated from 2020. But that's another story in a drama filled afternoon.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,448 admin
    #3
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    My experience with simple FLA car batteries...

    They last about 3 years if not cycled too much--I had a time where I was waiting for my kids and using reading lamp/various electronics/etc which tended to cycle the battery deeper (5x per week). At that time, batteries lasted something like 6-12 months less.

    If I ever had a battery go "dead" (car cranking and not starting, headlights left on, etc.) and battery was well discharged (would not crank engine)... I could jump/charge battery and it would work fine... For a few days to a few weeks--Then out of the blue, it would go "dead" (parking 20 minutes after driving a bit--Then dead type event). Happened to me, family, and even co-workers (I had suggested they change their 2+ year old battery or their car may not start in the next few days/weeks).

    My "cheap test"--Start the car once in a while with the headlights on first--And watch how much they dim. Works well with a "non-hybrid" vehicle to catch a weak battery.

    It looks like there are "Prius 12 volt battery conversion kits" (larger deep cycle battery to replace smaller OEM battery).

    https://elearnaid.com/opbawinewtob.html (know nothing about website or content)

    Which does confuse me a little bit with the Prius--I thought that the 12 volt starting battery was "maintained' by the traction battery pack... I.e,. the 12 volt battery would be "kept charged" even if loaded upwards of 100 Amps (i.e., AC inverter) until the traction battery was "discharged"... How is your traction battery bank working?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    #4
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    When I have to replace an old battery it always tests as bad. Measurements like low CCA, low voltage (bad cell), and resistance over 6. Will be interesting if I get around to testing it again today.

    That Prius battery conversion is a good idea for older Prius cars with the tiny battery. Mine is a 2012 with the larger battery. The traction battery does not feed the starter battery in my car. My traction battery should be fine for several years since I replaced it with a strong traction battery when I bought the car two years ago.

    It went stone cold dead in about 20 minutes time. Then returned to "good battery" after a 20 mile drive. Neither seemed possible. At any rate I am going to buy a replacement battery next time I make a "supply run".
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    #5
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    The 3 year old battery is pretty bad. After sitting overnight the CCA went down to 370 - though still more than enough to easily start a Prius. The resistance also went up to ~ 7.5 while voltage fell to ~12.4. Interestingly the same sized battery bought in 2012 also showed very similar CCA and resistance numbers after sitting for 1 1/2 months after the last charge.

    Still "impossible" though. It went stone dead in 20 minutes with no apparent discharge. 6.5 volts in 20 minutes, Something very odd happened.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • JRHill
    JRHill Registered Users Posts: 284 ✭✭✭
    #6
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    I have experienced the occasional and unexplainable low stating battery dilemma over the years on various rigs - always older stuff. The most recent was on an old+ Kubota B7100 toy tractor. When I bought it it was 10+ years old and the hour meter was broken - Lord knows for how long and the meter had a lot of hours on it.  One time good, the next not and it may even still be a bit warm. I ALWAYS had to cycle the glow plugs to start, even while warm. To use it in the winter took an hour on the engine heater and it was plugged into a maintainer constantly year around. Also, even while running it recharged the battery poorly but its factory alternator isn't anything to get excited about.

    One day I ran it too low on fuel and had to purge the air out of the line at the injector pump. Hood open, holding the clutch down and a hand on the wrench at the pump while turning the key I saw a very faint wisp of smoke coming from the lower left rear of the engine compartment - I was on the other side. Starter. It had only cranked for a short time. Nothing warm, connections were tight and the + cable relatively new. Dang it, I've done everything else but replace the starter. Amazon had the starter/solenoid and free shipping for $89.

    Replaced the starter. Cycled the glow plugs as usual and when I turned the key it startled me. I thought the thing was going to explode it spun so fast and fired immediately. On top of that I didn't need to cycle the glow plugs anymore unless stone cold. Yes, I know a diesel needs adequate starting RPMs esp on an old one but it had always been like it was so I accepted it as normal even with jumper cables.

    This doesn't explain the occasional low battery but I'd betcha if I tore the starter down I'd find a problem in the solenoid. Some internal resistance passing amps to the starter but also a varying phantom load. Maybe a build up of oil and copper sludge around the contacts? I'll find out one day as the old starter is sitting in the rebuild pile.

    The troubleshooting hints were there all along but I had dismissed them. Don't ya hate it when that happens? And all those years fighting to finally find the real problem. I'm this case it wasn't the battery but something totally unrelated. A low battery but only sometimes is something to ponder over a few beverages.
    Off Grid. Two systems: 1) 2925w panels, OB VFXR3648, FM80, FNDC, Victron BMV-712, Mate3s, 240 xformer, four SimpliPHI 3.8; 2) 780w, Morningstar 30a, Grundfos switch, controller and AC/DC pump, 8 T105. Honda EU7000is w/AGS. Champion 3100. HF 4550, Miller Bobcat.
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