Battery Electrolyte Level 2025 CX-5

[themp]

So, have had my CX-5 for 6 months and decided to look at the battery electrolyte level. Reading the user's manual it says to look at the side of the battery for the "Upper Level" and "Lower Level" I found them on the battery, they have a window to these markings. But, I used different flashlights and was not able to see any level at all. And I could not discern the six levels for each cell from the side. So, I took off the caps and looked in and saw the standard notch for filling that I have used for all my vehicles. The battery needed distilled water in all cells and I took them up to the plastic notch.

Anyone able to figure out how to use the markings on the side of the battery? Great idea but not very practical in my opinion.

 

[HyFlyer]

Shine the light from the opposite side? Or through the open cap for each cell?

 

[TheMAN]

they're hard to see and only very bright light MIGHT reveal them... the "full" level should touch the bottom of the tab in the filler hole on a Q-85 battery

on other batteries, such as 75D23, it might be the same, or 10mm below the bottom of the tab... it depends on who made the battery and when... Mazda uses Panasonic or Yuasa batteries for everything that comes from Japan

just make sure you put the battery on a charger after you top it off, otherwise the alternator might try to fast charge it and damage the battery because now the state of charge level is now different... not only will it possibly kill the battery, but also damage electronics or blow out light bulbs because of this

also make sure the caps, top of the battery, and any tools that you use to help refill the battery are clean... any contaminants in the battery could cause unexpected chemical reactions that can damage the cells

 

[Martyd]

just make sure you put the battery on a charger after you top it off, otherwise the alternator might try to fast charge it and damage the battery because now the state of charge level is now different... not only will it possibly kill the battery, but also damage electronics or blow out light bulbs because of this

I'm having a hard time believing this. There has to be enough safeguards to prevent any damage.

 

[madar]

I'm having a hard time believing this. There has to be enough safeguards to prevent any damaIe.

I believe this pertains to when you add acid to the battery, not distilled water. I never heard of it blowing out electronics though.

 

[N7turbo]

Plenty of batteries have been run from a low state after being jumped and the alternator charging them on the subsequent drive. It has probably happened millions of times.

 

[TheMAN]

I'm having a hard time believing this. There has to be enough safeguards to prevent any damage.

believe what you want, until see it happen... there are "safeguards" to "prevent" idiot drivers from killing themselves, yet it still happens.... the best locks still get picked by thieves

 

[TheMAN]

Plenty of batteries have been run from a low state after being jumped and the alternator charging them on the subsequent drive. It has probably happened millions of times.

there's a difference between low state of charge and that combined with acid stratification... without proper controlled conditions to recharge an acid stratified battery, you risk damaging the cells very quickly under a standard charging method... alternators are pretty dumb and will try to cram as much juice back into the battery as quickly as possible... you can jump a flat battery, and the car will run, but it doesn't mean the battery, alternator, or starter is going to last long without external intervention

a healthy battery that never really got ran down until an "oopsie" of leaving the headlights on might not be damaged or acid stratified, or even sulfated when dealt with quickly enough, but that doesn't mean the alternator can properly recharge the battery fully and without damaging them

besides that, that scenario does NOT factor in topping off the electrolyte... when you top it off, you potentially introduce acid stratification in a battery that might not have had it before... without proper recharging methods, you can't remove this and it can damage/destroy the battery

alternators are NOT and cannot replace battery chargers... they are there primarily to keep the car powered/running, and secondarily quickly replenish what "juice" was used from starting, and low alternator output (idling)... for the latter, they're designed for a battery with 90%+ state of charge, any less and you put strain on it and kill it from overuse

 

[Martyd]

While an alternator may be dumb, they are controlled by some pretty smart electronics. The days of the little black box voltage regulator are gone.
I'm 82 and have never heard of the examples you decribe, but that doesn't mean it never happened.

 

[TheMAN]

even a relatively modern mazda made in this century with "pretty smart electronics" regulator controlled by the ECU, rather than all integrated in the alternator, it dumb charges and can turn a good battery into a boat anchor quickly.... if they're that "smart", cars will tell you the battery's health and to replace the battery soon, as well as have more adaptive charging capabilities... but they don't... not even on mazda's with the i-ELOOP... it monitors voltage/state of charge, and switches between the wet capacitor and battery recharging, and that's pretty much it... only hybrids or EVs have true smart battery monitoring/charging capabilities, for only the high voltage battery for the electric motor

an acid stratified and/or sulfated battery causes erroneous state of charge readings with battery testers and simple charging regulators that are in cars, and means they will get improperly recharged and destroy cells, and potentially fry electronics and blow out bulbs from over voltage

all lead acid batteries have cells that sulfate to some degree over time because the alternator never recharges the battery to 100% in most conditions (a long road trip might), and from long term less than ideal state of charges (not anywhere near 80%), the acid also sulfates... you replenish it with distilled water, and that becomes even worse because of the differences in specific gravity between the liquids... and not to mention of cell "wear" (break down of the lead plates) due to repeated use over time... even on a healthy, relatively new battery that is not acid stratified, topping it off can still immediately cause it

the generally accepted safe way to recharge any lead acid battery without overheating the cells is with a slow smart charger... alternators always charge at a pretty high current, and the fast charging can kill a battery and alternator quickly if this goes on for an extended period of time (more than 30 minutes, and even shorter next to a hot engine)...

trying to recharge a weak or bad battery at high current and/or voltages not only can kill them quickly, but they dangerously boil out the electrolyte, overheating the battery and generating huge amounts of hydrogen gas (a byproduct of the charging chemical reaction)... if you want to literally blow up a battery, that's an easy way to do that with a dumb fast charger... fortunately, blowing up a battery on a moving car is pretty improbable because air currents move the hydrogen gases away, but in a garage, it can certainly happen... either way, it doesn't mean cell damage doesn't happen when you "fast charge"

smart chargers do not charge at any constant current or voltage, and can vary depending on the modes or cycle it is going through... a lot of times, they use pulse currents at specific voltages to desulfate or destratify a battery, before it attempts at a more constant current and gentle voltage to recharge it

lead acid maybe a tried and true technology that dates back well into the 19th century, but it also means it's been studied to death and improved over several generations... there's a lot of science in this low tech piece of equipment and what can be done to increase efficiency/life out of them (such as thinner, higher density cell structures in the "start stop" enhanced flooded batteries, to increase reserve capacity and deep cycling)