12v battery maintenance.

[neal adkins]

I found it interesting that the sticker on the 12v battery says maintenance free. But also has an indicator for when to add distilled water. Auto zone said I needed to change my battery because the test showed cranking amps were about 174 but should be 350 (from my memory of test). I got curious and removed the cap screws on top of the battery and found all of them very low on water. I filled all of them and now all seems well. I will see what happens tomorrow morning when I attempt to start the car. Then later get another battery test.

 

[MrFixit]

The battery indicator does not measure the electrolyte level, but rather, the specific gravity. As such, the indicator measures charge. It is quite possibe that if you had simply charged the battery, the cranking amps would have returned to normal (or, perhaps the battery is actually failing but not because of low electrolyte). I think some have had premature battery failure because low usage can cause the battery to discharge and repeated low charge levels will significantly degrade a battery. Have you been driving freqently, of have you had significant periods where the car has been idle?

I do agree that the electrolyte should not become especially low with a 'maintenance free' battery... Normally adding water is not necessary. When you looked in and found the 'low' level, were the plates still submerged, or could you see that the top of the plates were dry? Unless the top of the plates become dry, adding water may not accomplish anything.

 

[neal adkins]

The battery indicator does not measure the electrolyte level, but rather, the specific gravity. As such, the indicator measures charge. It is quite possibe that if you had simply charged the battery, the cranking amps would have returned to normal (or, perhaps the battery is actually failing but not because of low electrolyte). I think some have had premature battery failure because low usage can cause the battery to discharge and repeated low charge levels will significantly degrade a battery. Have you been driving freqently, of have you had significant periods where the car has been idle?

I do agree that the electrolyte should not become especially low with a 'maintenance free' battery... Normally adding water is not necessary. When you looked in and found the 'low' level, were the plates still submerged, or could you see that the top of the plates were dry? Unless the top of the plates become dry, adding water may not accomplish anything.

I do drive the car regularly. I average just under 1k miles per month. The indicators listed on the battery say: 1.ok 2.needs charging. 3. add distilled water.
Not sure why or how, but the water level was very low. I would say about 2.5 inches low in each slot. I added about 3 or more cups of water. Now it's Wednesday morning about 7am pacific time. No jumping nessacary. I did drive the car about 3 miles last night.
Another interesting point is why all the warning lights after disconnecting the negative battery cable? After adding water yesterday, I turned on the ready to drive mode (had to jump) and left ignition on for about 15 minutes but warning lights stayed on. But After I drove the car about 3 blocks I noticed all the warning lights off.

 

[MrFixit]

You're right of course !
I hadn't looked carefully at the "eye", and it does indeed indicate both low charge and low electrolyte level. It is a little tricky to interpret because of viewing angle and lighting. I just looked at mine (3Y, ~30K miles) and I beleive it indicates both good charge and good water level.

Based on your experience however, it might be good for people to check on this. One cause of low electrolyte is overcharging. The vehicle manages this (unless someone regularly uses an external charger). Perhaps the Clarity is being a little too aggressive when charging the 12V battery and is causing low levels over time.

To actually access the water level, do the 6 small plastic "Phillips Head - looking" screws across the top un-screw? I tried a couple of mine and they weren't loosening before they began to distort, so I stopped trying.

Yes, The warning lights after a 12V power loss has been repeatedly noted as "normal" for the Clarity.
Like you, this puzzles me... It is very odd that the vehicle would assume that all these problems exist just because power was interrupted. Your experience of driving a few miles to clear them is exactly right, but Honda could have done a better job on this one.

 

[neal adkins]

You're right of course !
I hadn't looked carefully at the "eye", and it does indeed indicate both low charge and low electrolyte level. It is a little tricky to interpret because of viewing angle and lighting. I just looked at mine (3Y, ~30K miles) and I beleive it indicates both good charge and good water level.

Based on your experience however, it might be good for people to check on this. One cause of low electrolyte is overcharging. The vehicle manages this (unless someone regularly uses an external charger). Perhaps the Clarity is being a little too aggressive when charging the 12V battery and is causing low levels over time.

To actually access the water level, do the 6 small plastic "Phillips Head - looking" screws across the top un-screw? I tried a couple of mine and they weren't loosening before they began to distort, so I stopped trying.

Yes, The warning lights after a 12V power loss has been repeatedly noted as "normal" for the Clarity.
Like you, this puzzles me... It is very odd that the vehicle would assume that all these problems exist just because power was interrupted. Your experience of driving a few miles to clear them is exactly right, but Honda could have done a better job on this one.

The resistance is the sticker over the top of the large screws. If you keep screwing them out the sticker will just break loose

 

[Landshark]

Not sure why or how, but the water level was very low. I would say about 2.5 inches low in each slot. I added about 3 or more cups of water.

That’s quite a bit of water to add to such a small battery. To what level did you fill the cells? Up to the bottom of the fill opening? A half an inch below the opening? Just above the plates by a 1/4-1/2”?

Requiring that amount of water, in my experience, would indicate that either the battery was not properly filled prior to being placed in service or, it has been subject to repeated deep discharges and numerous equalization cycles. Typically, a couple of deep discharges will kill the battery and an equalization isn’t possible under normal operating conditions.

 

[neal adkins]

That’s quite a bit of water to add to such a small battery. To what level did you fill the cells? Up to the bottom of the fill opening? A half an inch below the opening? Just above the plates by a 1/4-1/2”?

Requiring that amount of water, in my experience, would indicate that either the battery was not properly filled prior to being placed in service or, it has been subject to repeated deep discharges and numerous equalization cycles. Typically, a couple of deep discharges will kill the battery and an equalization isn’t possible under normal operating conditions.

I'll admit that when I saw how low is was that I was disappointed because it says maintenance free on the battery. I filled about a little below the slot showing full in side of each cell. The battery is still working but the indicator shows needs charging even after a long drive. So I will connect to my charger and attempt to charge it up and see what happens.

 

[Steven B]

Battery replaced proactively. Vehicle purchased Dec 2017, 48k miles. With vehicle off in 50 deg garage, voltage measured 12.4, dropping to 12.2 with lights on.

Not sure why nothing on the original battery told me the size to buy. Thanks to the forum for identification of 51R, bought at Wallyworld for $140.

Further detail:
- Electrolyte level was right in the middle between Lower and Upper Level lines on the original battery. Eye reported good.
- Original battery says 310 CCA and had a 3yr warranty from Honda, but could find no replacement with CCA that low with 3yr warranty. Japan must make the best batteries.

 

[Landshark]

Thanks to the forum for identification of 51R, bought at Wallyworld for $140.

- Original battery says 310 CCA and had a 3yr warranty from Honda, but could find no replacement with CCA that low with 3yr warranty. Japan must make the best batteries.

FWIW: The Honda replacement battery carries a 100 month warranty, prorated after 36 months. I believe it is priced similarly to what you paid at Walmart. Costco caries an Interstate 51R for $100, which has a 36 month warranty.

 

[neal adkins]

I had called interstate and they had a blemished battery for 47.99. So I bought it and installed last night even though the car was.drivable with old battery. When I tried charging the old battery the voltage went up to 16.2 volts in about 3 minutes and then showed charged soon after. Since the indicator on the battery still showed charging nessacary I replaced the battery.