What % Of A Battery's Rated A-h Capacity Is Acceptable?

[Number_35]

This is my wife's friend's car, a 2021 Hyundai Venue.

It did not come with a block heater, and did not start this morning (or even turn over) even with a boost. It was a chilly -32°C this morning.

I removed the battery, brought it home, thawed it out, and charged it.

It passed the load test (Schumacher resistive tester - 100 A for 10 s - with flying colours.

I now have it on my ampacity-testing rig, drawing about 8 A. Here's the set-up:

The battery is original, and is rated at 45 A-h and 410 CCA. In perfect condition, then, it should supply 8 A for over 5 hours.

What if it quits at 4 hours (< 80%)? 3 hours (< 60%)?

Is there a rule-of-thumb for when the battery should be replaced?

Thanks!

P. S. Regarding the absent block heater, I won't install one in this weather, but will lend her my magnetic surface-mount 200 W heater.

 

[FZ1]

This is my wife's friend's car, a 2021 Hyundai Venue.

It did not come with a block heater, and did not start this morning (or even turn over) even with a boost. It was a chilly -32°C this morning.

I removed the battery, brought it home, thawed it out, and charged it.

It passed the load test (Schumacher resistive tester - 100 A for 10 s - with flying colours.

I now have it on my ampacity-testing rig, drawing about 8 A. Here's the set-up:
View attachment 253915

The battery is original, and is rated at 45 A-h and 410 CCA. In perfect condition, then, it should supply 8 A for over 5 hours.

What if it quits at 4 hours (< 80%)? 3 hours (< 60%)?

Is there a rule-of-thumb for when the battery should be replaced?

Thanks!

P. S. Regarding the absent block heater, I won't install one in this weather, but will lend her my magnetic surface-mount 200 W heater.

Crummy oem battery. Go to Walmart and get a Wm Maxx. Try to get 700 cca. You can look up the proper size for the car on the Wm site. Generally, you want the biggest battery that will fit the battery space. Good luck with it.

 

[Rmay635703]

This is my wife's friend's car, a 2021 Hyundai Venue.

It did not come with a block heater, and did not start this morning (or even turn over) even with a boost. It was a chilly -32°C this morning.

I removed the battery, brought it home, thawed it out, and charged it.

It passed the load test (Schumacher resistive tester - 100 A for 10 s - with flying colours.

I now have it on my ampacity-testing rig, drawing about 8 A. Here's the set-up:
View attachment 253915

The battery is original, and is rated at 45 A-h and 410 CCA. In perfect condition, then, it should supply 8 A for over 5 hours.

What if it quits at 4 hours (< 80%)? 3 hours (< 60%)?

Is there a rule-of-thumb for when the battery should be replaced?

Thanks!

P. S. Regarding the absent block heater, I won't install one in this weather, but will lend her my magnetic surface-mount 200 W heater.

Nope, it’s subjective and typically cold cranking amps over the duration of 3 cranks. Not the actual amphours.

That said a battery with very little capacity can have passing cranking amps especially in warm weather and become garbage when it’s cold out .
If it’s capacity is too low it might have enough winter cranking amps but be found dead from parasitic draw at the end of the day.


Usually you don’t get much warning when it dies besides being a little weak or slow cranking.

 

[bullwinkle]

A battery blanket would be a good choice, or a bigger battery! What did you boost it with? Some of these portable 4000-6000A lithium ones are unbelievable, & small enough to bring inside to keep warm & charged.

 

[Jim_Truett]

You don't want to take lead acid below 50% depth of discharge or you'll shorten it's cycle life. That being said, if it froze it's done anyway. If you try to pull 8A for 5+ hours you'll fully deplete it and exceed 50% DOD. It probably won't happen due to age and the increasing internal resistance as it discharges will have that inverter shut off on low voltage protection long before you hit that time.

 

[twX]

The amp-hours a battery provides depends on the discharge rate, with higher load reducing capacity. The Ah rating is probably based on a slower discharge than 8 A, so you can expect it to be lower than the rating.

Any car parked outdoors in Winnipeg is going to need a block heater whether it has a good battery or not, so that's where I'd start. With a block heater, the battery might be good enough. However, it's almost 5 years old, only rated 410 CCA, and already out of the car. I'd just replace it with a new 600+ CCA battery.

 

[hemitom]

My dad had an old friend who was a mechanic I remember him telling us his rule of thumb was 100 c.c.a per 100 cubic inch of displacement. mind you this was in the 1970's and you were trying to start massive engines .
I remember my dad replacing the battery in the 73 New Yorker, at that time the biggest battery he could find was 550 c.c.a .
the 440 would start if plugged in at 30 below zero . Not plugged at 30 below she wouldn't crank fast enough to start.

So in Winnipeg I would try and fit a bigger battery or the biggest you can fit in. AT minus 32 C and with no block heater you never have enough c.c.a .

 

[eljefino]

That looks like the oddball size that came with my wife's 4th gen Prius. Get out your tape measure, I think a 26 (maybe R) is an inch taller but otherwise fits.

 

[oil pan 4]

Crummy oem battery. Go to Walmart and get a Wm Maxx. Try to get 700 cca. You can look up the proper size for the car on the Wm site. Generally, you want the biggest battery that will fit the battery space. Good luck with it.

That's what I did on my truck.
It had a pretty large group 27 and I figured I could make an even larger group 31 fit. So I did.
A group 31 can lose like 20% of its capacity and still have more power than a top of the line group 27.
Plus the group 31 I got was free so that was my motivation.
Starts up like a warm day when it's +5f.

 

[Nukeman7]

The OEM battery on the Venue is an oddball Group 47 (H-5) size. See if a Group 24F or 35 will fit in the battery space and if the cables will reach the terminals. Those two are the most common sizes which are available in 3 grades from WalMart and any store selling automotive batteries.

 

[Number_35]

My dad had an old friend who was a mechanic I remember him telling us his rule of thumb was 100 c.c.a per 100 cubic inch of displacement. mind you this was in the 1970's and you were trying to start massive engines .
I remember my dad replacing the battery in the 73 New Yorker, at that time the biggest battery he could find was 550 c.c.a .
the 440 would start if plugged in at 30 below zero . Not plugged at 30 below she wouldn't crank fast enough to start.

So in Winnipeg I would try and fit a bigger battery or the biggest you can fit in. AT minus 32 C and with no block heater you never have enough c.c.a .

Dad had a '67 Chrysler with a 383. We lived in Edmonton for the first couple of years he had it. As I recall, it had two block heaters. It also had an onboard charger, which he swore by. I checked it out many years later, after I knew more about technical stuff. It was actually an old 6 V charger, so I doubt it helped at all. I gave it to a fellow at work who had old VWs.

 

[Number_35]

The amp-hours a battery provides depends on the discharge rate, with higher load reducing capacity. The Ah rating is probably based on a slower discharge than 8 A, so you can expect it to be lower than the rating.

Any car parked outdoors in Winnipeg is going to need a block heater whether it has a good battery or not, so that's where I'd start. With a block heater, the battery might be good enough. However, it's almost 5 years old, only rated 410 CCA, and already out of the car. I'd just replace it with a new 600+ CCA battery.

If it were my car, I would. Money is a factor for the owner.

 

[Nukeman7]

If it were my car, I would. Money is a factor for the owner.

If a Group 24F or 35 will fit, WalMart sells an EverStart Value battery for only $70 (USD).

 

[Number_35]

A battery blanket would be a good choice, or a bigger battery! What did you boost it with? Some of these portable 4000-6000A lithium ones are unbelievable, & small enough to bring inside to keep warm & charged.

The lady's boyfriend boosted it with cables, and later I tried with my NOCO jumper pack. Got a single starter-solenoid click - not even a death rattle.

 

[oil pan 4]

The lady's boyfriend boosted it with cables, and later I tried with my NOCO jumper pack. Got a single starter-solenoid click - not even a death rattle.

Yeah lithium batteries suffer from catastrophic cold performance, called cold numbing. That's why a lot of electric cars still use a 12v lead acid battery for starting. They're reliable. It's why Tesla's freeze solid and go into brick mode and my Nissan leaf laughs at -30. My range is cut in half but at least it turns on.

 

[Number_35]

If a Group 24F or 35 will fit, WalMart sells an EverStart Value battery for only $70 (USD).

The cheapest battery I've found so far is at Canadian Tire, at around C$180. She's a Costco member (which I'm not), so that might be a better bet.

Yeah lithium batteries suffer from catastrophic cold performance, called cold numbing. That's why a lot of electric cars still use a 12v lead acid battery for starting. They're reliable. It's why Tesla's freeze solid and go into brick mode and my Nissan leaf laughs at -30. My range is cut in half but at least it turns on.

My booster pack lives in the van. Our garage was around -12 C last night. That may be why it didn't do much good boosting this morning.

I'll keep it in the house, and take it out with me when I think of it.

 

[Number_35]

You don't want to take lead acid below 50% depth of discharge or you'll shorten it's cycle life. That being said, if it froze it's done anyway. If you try to pull 8A for 5+ hours you'll fully deplete it and exceed 50% DOD. It probably won't happen due to age and the increasing internal resistance as it discharges will have that inverter shut off on low voltage protection long before you hit that time.

The battery was down to 11.0 V after about 90 minutes. I didn't want to damage it, so shut things down.

 

[WobblyElvis]

Doing the math, the battery has a capacity of about 20AH. It's done! Costco has a very good battery warranty. I think it's 4 years no questions asked for a free replacement.

 

[hemitom]

The cheapest battery I've found so far is at Canadian Tire, at around C$180. She's a Costco member (which I'm not), so that might be a better bet.

My booster pack lives in the van. Our garage was around -12 C last night. That may be why it didn't do much good boosting this morning.

I'll keep it in the house, and take it out with me when I think of it.

just replaced the battery in the in-laws 2015 rio it calls for 121r this may fit in the venue .
bought at Canadian tire $190 taxes in. its 550 c.c.a. the h5 group 47 also fits into the rio as well so I'm thinking the 121R will fit and a cheaper option for her.

 

[GSCJR]

Get a new group 47 and be done with it, it drops right in; no mucking around.