# Automotive battery question, nothing to do with solar

Registered Users Posts: 35 ✭✭
Just curios about a battery I had in my Jeep years ago. It would full on crank to start time after time no matter how many times you asked in a day. Just blast until it started, like if you put in a brand new battery.

Play the radio when sitting on AUX for 10 minutes, dead as a door nail.

Have a new battery but always wondered what was going on .

## Comments

• Super Moderators, Administrators Posts: 33,260 admin
What kind of battery was it? Just a standard automotive FLA battery? Or something else (deep cycle, AGM, etc.)?

In general, when FLA batteries fail, the plates become sulfated and/or corroded. This tends to "increase" the battery's internal resistance, and reduce the surge current for starting.

I have seen "old/failing" car batteries fail after an hour of running a radio, kids playing video games, etc. The sulfates make less "active material" available for producing current. Effectively reducing the battery AH capacity. If the remaining active plate area was enough to provide starter current, and otherwise very little AH capacity, a "smaller load" running for minutes (or a couple hours) could effectively drain the battery.

Of course, there are 6 cells--So you could have 4-5 "good cells" and 1 or 2 bad/weak cells that degrade overall battery performance.

Looking at the "math", starting is not that much AH capacity vs other loads. Making up numbers:
• 80 amps starting current * 5 seconds cranking * 1/3,600 seconds per hour = 0.11 AH of battery "usage"
• 5 amp radio current * 10 minutes / 60 minutes per hour = 0.83 AH of battery usage
Give that a "typical" car battery may be 80 AH, neither of the above loads use significant battery capacity (of a good battery).

However, you can see that 10 minutes of a radio can use almost 8x more AH capacity than a typical cranking load does... So the radio could "kill" the battery capacity faster than an a typical starting cycle.

Depending on lots of over variables, Lead Acid batteries can have a "surface" charge where their "resting voltage" is relatively high--And after a few hours or days, the resting voltage could fall. So if you were running the Jeep every day--The battery could be "surface charged" enough to start the vehicle, but other loads (radio, lights, etc.) could take the battery "flat" enough to prevent starting/running the electronics.

-Bill "my guesses" B.
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 6,579 ✭✭✭✭✭
What kind of music was it for 10 minutes? The group below could do this at concert levels in your Jeep

"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 6,579 ✭✭✭✭✭
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Registered Users Posts: 35 ✭✭
Thank you Bill, it was a lead acid battery so I'm sure your explanation was my problem.

Dave, I'm sure I was listening to Frank Zappa when I killed the battery,

• Registered Users Posts: 253 ✭✭✭
I bought a new battery for my car and a couple months later I would have to charge it to start if I let it sit a couple days. Took it back for exchange.  Guy said it was the car.  His computerized tester said the battery was at 11.5V and just needed a charge as it could put out full amps. I'll give you a battery, but don't come back again. Haven't been back in three years.  I think it was a shorted cell, but vehicles can start with just 9V. Not sure what the actual issue was.

Another vehicle died playing the radio for about 45 minutes. I had another battery which read zero volts.  Put it on a 10A charger and it took 15 minutes before it started drawing current. Then it got 45 minutes charge.  There couldn't have been more than 7AH in the battery, but it started the car.

Batteries can be strange. For a while I was bringing home batteries from town recycling to experiment with.  I would revive them with my water heater which created pulses.  Best luck has been with those that were completely drained.
• Solar Expert Posts: 6,579 ✭✭✭✭✭
I know Costco has replaced alot of their Flooded batteries with AGM's.   They are physically smaller also on some.

Interstate is not always outrageously dependable😉
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Super Moderators, Administrators Posts: 33,260 admin
Another experience I had with car batteries... If the batteries are over 1+ years old, and the battery has been taken dead (lights left on, cranking the non-starting engine until dead, etc.)--I have found that once the battery is recharged and any loads have been "fixed" (starting problem fixed, etc.)--The battery may work fine for a few days to a couple of weeks, and then die. This even happens when a car has been driven and parked for a few hours (driven/properly charging, etc.).

These days, if I want a reliable car--Any older batteries that have been taken dead--I just replace them.

Other quick test... Every once in a while I start the car with the headlights on (typically evening or night) and notice how much they dim. When the battery gets weak (near replacement time), I note the headlights dim quite a bit on the older/soon to be failing battery. Another indication that a new battery is due.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Registered Users Posts: 35 ✭✭
I have been replacing my auto batteries wit AGM' s .  4 and a half miles off the main road on a forest service road. The county maintains it but sometimes its a 40 mph cruise, other times its a mud bog or total wash board that will rattle your fillings out. Not complaining, once I get home its paradise for me.
The wash board rough roads is what made me change to AGM, no more acid all over the place.
Hit 101 just now today at 6000' in the Gila. I have so much solar I can run a portable AC all day, Mini split coming soon.

• Solar Expert Posts: 6,579 ✭✭✭✭✭
What split did you order?
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Registered Users Posts: 35 ✭✭
I'm looking at a Senville Aura  12000 BTU  25 seer, 220 volts
• Solar Expert Posts: 6,579 ✭✭✭✭✭
You have an installer who will drive down that road for warranty? Not a bad unit.

Back in the days before I stopped traveling I could be "rented" for a day to evac a line-set and leak test. Might still do it if you were in Hawaii.
Hmm  not this week, tropical storm heading in to Maui.
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Registered Users Posts: 35 ✭✭
I plan to install it myself. Let me know what you think of this.

https://www.pioneerminisplit.com/products/kwik-e-vac-line-set-flushing-kit-for-mini-split-air-conditioning-systems

looks interesting, would save me from buying a vacuum pump and gages.
• Solar Expert Posts: 6,579 ✭✭✭✭✭
edited July 19 #14
Will look later got to get out before the heat.  No warranty is not an issue?  I guess the price is worth the risk. The Fugitsu I use alot in this size is 30 SEER. More denaro though. Did you look at the section on splits here in Energy? Back when the forum was really humming there were some good gems in there.

What has happened to forums these days? Youtube and Tiktoc.....

How about starting a new thread in the link below?

https://forum.solar-electric.com/discussion/23007/mini-split-update-for-offgrid#latest

"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 1,966 ✭✭✭✭✭

What has happened to forums these days?

I think everybody went to the  DIY Solar Forum. They're getting posts every few minutes or better.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Solar Expert Posts: 6,579 ✭✭✭✭✭
Yea but it is down there also, I think. That is the one that Mike (RIP)  ran right?
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 1,966 ✭✭✭✭✭
edited July 19 #17
No Dave, it is ran by Will Prowse. It is super busy nearly 24 hours a day. Worldwide membership. Nine comments in the last 1/2 hour. In the morning there may be well over a hundred comments an hour. 1698 pages of members.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Solar Expert Posts: 6,579 ✭✭✭✭✭
Will take a look ! Staying cool down there?
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 1,966 ✭✭✭✭✭
Will take a look ! Staying cool down there?
Barely, The humidity is through the roof and zero relief at night. I do have ac I run at night in my bedroom. Helps me to be able to sleep.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Solar Expert Posts: 1,966 ✭✭✭✭✭
Thank you Bill, it was a lead acid battery so I'm sure your explanation was my problem.

Dave, I'm sure I was listening to Frank Zappa when I killed the battery,

Great Googly Moogly!

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Solar Expert Posts: 6,579 ✭✭✭✭✭
Yea it is most everywhere in the US. We are lucky at 4700 feet that we do cool down at night.

Tropics look decent

"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 1,966 ✭✭✭✭✭
Yea it is most everywhere in the US. We are lucky at 4700 feet that we do cool down at night.

Tropics look decent

The ocean is 95 degrees right now, and rising. No relief there either.

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Solar Expert Posts: 6,579 ✭✭✭✭✭
Any evening breeze? I remember getting up at 5am and rubbing down to clean the boat decks while they were wet from  Baja condensation. There was about a 30 minute window and then it evaporated.

The screen shows the Tuantapeckers in Southern MX and Papagallos in Costa Rica blowing hard. Those areas are in the top 7 places in the world to really face BIG winds. Another is Pt Conception in SoCal. The winds are like a switch. They come up without much warning. Another tropical storm heading for Hawaii.

Just another Summer !

"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail [email protected]

• Solar Expert Posts: 1,966 ✭✭✭✭✭
edited July 20 #24
No breeze for a few days now. Single digit speed, at best.Up until a few weeks ago it had been nice .High 80's,low90's and low humidity. Then the flood gates opened up and the humidity has been pretty bad. Here's something I just posted on our local facebook page.

I had to google "heat Index" to satisfy my curiosity. Turns out the heat index is what it actually feels like taking into consideration all the outdoor factors. I The way I feel right now I can't disagree with my weather station.
https://www.nytimes.com/article/what-is-the-heat-index.html

2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

• Registered Users Posts: 35 ✭✭
I think its cool that Jesse Ventura is your neighbor

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