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Didn't someone do an experiment and towed an EV and charged it? LOL

We know full power on the EV is 200hp/150KW. How much to be able to move it?
 

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Come to think of it, how many watts are required to start the Bolt? I would think a hand crank generator could be enough to close the contactors and start the vehicle.

Here I was imagining a peak output of perhaps 300 watts for a few seconds pushing the Bolt across the parking lot, LOL.
 

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This should be sufficient.
 

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Come to think of it, how many watts are required to start the Bolt? I would think a hand crank generator could be enough to close the contactors and start the vehicle.

Here I was imagining a peak output of perhaps 300 watts for a few seconds pushing the Bolt across the parking lot, LOL.
A hand crank for emergency use when the 12V is dead sounds like a good idea! I don’t know if it would work, but . . .

😀
 

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A hand crank for emergency use when the 12V is dead sounds like a good idea! I don’t know if it would work, but . . .

😀
Probably not for ICE as cranking an engine is hard work. An EV's 12V only needs to activate the HVDC system. After that, the DC-DC converter starts charging the 12V.
 

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Probably not for ICE as cranking an engine is hard work. An EV's 12V only needs to activate the HVDC system. After that, the DC-DC converter starts charging the 12V.
Yeah, I assumed we were only discussing the Bolt, not ICE vehicles.

Although I have had experience hand cranking ICE vehicles. 30’s vintage and much lower compression than modern ICE. Even then it wasn’t always easy. Often it was easier to just do a push start!
 

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Yeah, I assumed we were only discussing the Bolt, not ICE vehicles.

Although I have had experience hand cranking ICE vehicles. 30’s vintage and much lower compression than modern ICE. Even then it wasn’t always easy. Often it was easier to just do a push start!
Yep, it's very hard work. When I was reading up on ways to charge 12v battery during power outage, it's recommended that you do foot pedal instead of hand crank. As with everything, though, it's easier to move electrons (solar) vs moving solid stuff like wind/animal powered.
 

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Although I have had experience hand cranking ICE vehicles. 30’s vintage and much lower compression than modern ICE. Even then it wasn’t always easy.

Remember to keep your thumb on the same side of the crank as your fingers. That was a the trick back in the day, to prevent breaking your thumb when the motor backfired.

Even kicking over big displacement bikes in the 1960's could bruise the bottom of your foot, and launch you into the air.
 

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Remember to keep your thumb on the same side of the crank as your fingers. That was a the trick back in the day, to prevent breaking your thumb when the motor backfired.

Even kicking over big displacement bikes in the 1960's could bruise the bottom of your foot, and launch you into the air.
Thanks, if this advice was directed to me personally, but I learned from my grandfather over 60 years ago how to crank start car, truck, and tractor engines. In spite of that my grandfather once had a tractor crank break his arm. It is inherently a dangerous operation!
 

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Thanks, if this advice was directed to me personally, but I learned from my grandfather over 60 years ago how to crank start car, truck, and tractor engines. In spite of that my grandfather once had a tractor crank break his arm. It is inherently a dangerous operation!
This would be a great additional feature to Ford EVs. Spot to put the tire iron which recharges the 12V. LOL

 

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Discussion Starter · #52 ·
I've received a lot of great information so far:

As to changing the 12V AGM myself:
  • do it ! but be careful, wear protection (per post#2 by Neptunenínja)
  • when removing the old battery: disconnect negative first, then positive (per post #5 MikeyBolt)
  • when installing the new battery: positive first, then negative
  • unhooking the old battery without simultaneously maintaining charge to the 12V system: doesn't seem to result in much loss of memory items in the car (post #2, post #5)
> why is that? does the KAM carry a little juice in it for when the battery is disconnected?
As to maintaining or extending the life of the 12V battery:
  • charge the 12V battery periodically (every 6 months per post #3 drdiesel, )
  • use a battery maintainer not a trickle charger (post #30 Knucklehead, post #33 NortonCommando)
As to checking the health of the 12V battery:
  • do a load test or have a load test done (post #12 redpoint5, post#36 Sean Nelson)
  • get a load tester & test battery every 6 months (post#27 Aealessandra)
  • but, load testers may not be reliable (post#28 NortonCommando)
As to responding to an "emergency":
-carry a "jump pack" (post #12 redpoint, post#13 Mike DZ, post#27 Aealessandra)
- try a pedal generator (seriously??—why not wind or solar or hydrogen or coal/steam,etc..) although quite pricey and scarce (post#43 p7wang)

As to the best writeup on the 12V Charging System and Operation
- see post #6 of this thread (drdiesel1 August, 2017)

Which way to go, I think it depends on one's own personal interests, preferences and tolerance for risk.

Personally I don't worry about an "emergency" even if my Roadside Assistance is expired I've still got roadside service on one of my credit cards so I don't feel compelled to carry a jump pack around. And there's a pretty good chance that a paranoid passer-by with a jump pack will come to my rescue.;)

Load testing sounds good to me but need to find a load tester that actually works. And insofar as charging I've already got a Battery Tender Junior maintainer from my motorcycling days that might work.

Thanks all.
 

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Discussion Starter · #53 ·
So according to my new load tester/battery analyzer, my battery is "good" but needs charging:
battery load test 01-05-2021.JPG charge time needed for OCV and SOC.jpg old battery charger2.JPG
Presently has open circuit voltage= 12.47 and 438 CCA's versus spec. of 520. Seems like it might be around 60-65% SOC.

Can't find the battery maintainer I thought I had. Although I found my old 1990's vintage battery charger used previously only for charging lead acid flooded boat batteries. And I've read that you don't need a special charger for AGM batteries?

My old charger doesn't have a selector for manual versus automatic, so I'm guessing it's just a dumb charger that doesn't taper or measure anything about where the battery is at.

According to the chart for AGM, looks like it's going to need around 3-4 hours charging at 10A in order to get the battery up to 100% SOC. To be safe, I'll charge it for 2 hours at 10A then retest. I'm glad I'm getting into this, hopefully I won't toast anything.;)
 

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So according to my new load tester/battery analyzer, my battery is "good" but needs charging:
View attachment 34741 View attachment 34742 View attachment 34745
Presently has open circuit voltage= 12.47 and 438 CCA's versus spec. of 520. Seems like it might be around 60-65% SOC.

Can't find the battery maintainer I thought I had. Although I found my old 1990's vintage battery charger used previously only for charging lead acid flooded boat batteries. And I've read that you don't need a special charger for AGM batteries?

My old charger doesn't have a selector for manual versus automatic, so I'm guessing it's just a dumb charger that doesn't taper or measure anything about where the battery is at.

According to the chart for AGM, looks like it's going to need around 3-4 hours charging at 10A in order to get the battery up to 100% SOC. To be safe, I'll charge it for 2 hours at 10A then retest. I'm glad I'm getting into this, hopefully I won't toast anything.;)
If you have 2A, maybe do that instead. Can't do much damage on 2A charging. I have a smart charger that tapers and I set it on 2A.
 
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Discussion Starter · #55 ·
If you have 2A, maybe do that instead. Can't do much damage on 2A charging. I have a smart charger that tapers and I set it on 2A.
,
Yes, I did two things:
1.) Without driving the Bolt anywhere. I plugged the Bolt in overnight taking the high voltage battery up to 88-89% hilltop SOC. The 12V AGM then moved up OCV from 12.47 to 12.6 and CCA from 438 to 461. So having the Bolt plugged in seems to help the 12V a little bit.
2.) Then charged the 12V AGM at 2A for 2 hours. Result: OCV= 13.0, CCA= 471, SOC= 100%, SOH (state of health)= 92%

I googled state of health (SOH) and saw that for a conventional lead acid battery, 75% SOH or lower means you should replace the battery. Couldn't find what the SOH criteria for an AGM is. Although I get the feeling that my current SOH at 92% means I can keep going with my current battery for a while longer ?
 

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As to responding to an "emergency":
-carry a "jump pack" (post #12 redpoint, post#13 Mike DZ, post#27 Aealessandra)
- try a pedal generator (seriously??—why not wind or solar or hydrogen or coal/steam,etc..) although quite pricey and scarce (post#43 p7wang)
Be aware that the jump packs self-discharge and so you need to charge them periodically to make sure they still have enough juice to work in an emergency. The one I bought seems to discharge to around 75% of its capacity after 3 months, so I recharge that often. I actually discharge it first by charging my tablet and note how far it charged the tablet to track whether it's loosing oomph or not. So far, so good.

As far as a crank or pedal generator, I'm a bit skeptical. You'd need to disconnect the 12V battery and I'm not sure if the car will run properly without the 12V battery once it's started. If you leave the 12V battery connected then all of your cranking or pedaling efforts are going to be absorbed by the battery and you may not be able to get the voltage up high enough for the car to start.
 

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Discussion Starter · #57 ·
So I did my new load tester/analyzer routine again this morning. Hadn't driven the Bolt at all

(covid restrictions here allow police to pull you over, if you're not going to the grocery store or to a medical appointment you could be fined).

Anyway, my readout now this morning says 90% SOC and "Good Battery - Recharge". wt-f

Could be:
1. My wonderful new tester is bad.
2. My battery is bad, it leaks CCA/SOC
3. I've got something parasitic in my 12V system in Bolt
4. Some or all of the above

Should I be concerned... what should I do now?
 

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3. I've got something parasitic in my 12V system in Bolt

Should I be concerned... what should I do now?
Of course there are systems using the 12V battery when the Bolt is just sitting there.
There is the Onstar cellphone receiver, the key fob receiver, and gadknowswhatelse is using the 12V battery.
I think I read something about the car going into a deeper sleep after X amount of time, but even then there is a draw on the 12V battery.

Always be concerned. It's human nature!

And as I said before, I don't put a lot in these quickie 'load testers'.
The Bolt 12V battery never sees much of a load. The most it would ever see is sitting with the car NOT powered on and the headlights and emer flashers ON, running off the 12V.

I only trust an actual capacity test of the 12V battery.
That puts a set load on the battery and takes it down to a ~10V cutoff, displayed in minutes.
(15A for an hour on a 15Ah rated battery for example.)
But car batteries use a goofy RC rating, Reserve Capacity which can be converted to an Ahr rating.
 

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Discussion Starter · #59 ·
I only trust an actual capacity test of the 12V battery.
That puts a set load on the battery and takes it down to a ~10V cutoff, displayed in minutes.
(15A for an hour on a 15Ah rated battery for example.)
But car batteries use a goofy RC rating, Reserve Capacity which can be converted to an Ahr rating.
According to AC Delco the reserve capacity of my stock AC-Delco 12V AGM battery was 80 minutes when new.

I've read that this 80 minutes reserve capacity is the number of minutes for which it can run at 25 amps of current without its voltage dropping below 10.5 volts.

The 80 minutes converts to to 33-1/3 amp hours. So if I find a way to draw 33.3 amps for an hour and then check the remaining voltage and I see then, for example, it's 9.5-volts. Below the 10.5V benchmark, what does that tell me about the battery ? Is it good or no good ?
 

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....I've read that this 80 minutes reserve capacity is the number of minutes for which it can run at 25 amps of current without its voltage dropping below 10.5 volts...
Good job on the research! That's the automotive method of stating an Ahr rating.
All auto batteries are tested on a 25A load,, for some reason.:rolleyes:

Ideally you don't want to drop below 10-10.5 V because it is hard on a lead acid to be taken that low.
Definitely get it charging back up right after the test on a charger, but not a high Amp charger.

The Cap Check can also be run at 0.5C which in this case would be ~16A for 2 hours.
The problem with fixed resistors, such as a string of headlights, as the volts drop the amps drop.
But if you baby sit it, you'll get a good idea if the battery is near what it's rated.

Modern Cap Testers may not be expensive if you don't need high Amp testing.
They convert Amps to heat and use a fan to blow it away.
 
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