Do battery chargers wear out?

[Wdeertz]

I have a Charles Industries 24v 60 amp battery charger on my flooded start bank. According to the manual the charge profiles should be as follows:

Flooded Bulk/Absorption 29v float 27.2v
AGM Bulk/Absorption 28.4v float 26.8v

I confirmed that the battery charger switch is set to flooded and am only seeing 28.6v bulk and 26.8v float. I thought maybe the switch was mislabeled so I tried the AGM setting. With the AGM setting I saw bulk of 28v and float of 26.4v. In both situations I’m seeing a voltage of 0.4v lower than the profile should be.

So my question is do battery chargers wear out? Is there a component on the charger board causing it to deliver 0.4v lower than what it should?

 

[Tator]

Are you taking the reading directly from the charger or is it from your battery posts or perhaps a gauge somewhere in a different location than the charger?
Readings from other than directly on the charger can be lower due to even slight resistance in the cable, connectors, fuses, etc.

Tator

 

[Wdeertz]

Are you taking the reading directly from the charger or is it from your battery posts or perhaps a gauge somewhere in a different location than the charger?
Readings from other than directly on the charger can be lower due to even slight resistance in the cable, connectors, fuses, etc.

Tator

Yes I should have mentioned in my original post the readings are directly on the battery charger posts.

 

[tiltrider1]

Is it possible that the wire used is undersized and you are experiencing voltage drop?

 

[KnotYet]

Charger output voltage can be affected by the batteries' condition.

 

[Wdeertz]

Batteries are less than 1 month old and all voltage readings are being taken at the charger terminals so no voltage drop.

 

[Delta Riverat]

Maybe. At least the voltage is a little low (safe) than a little high (boil off electrolyte)

 

[KnotYet]

Batteries are less than 1 month old and all voltage readings are being taken at the charger terminals so no voltage drop.

OK, can you indicate what you are taking the voltage readings with?
Are its batteries OK? Have you taken past readings that concur with the manual?

 

[Wdeertz]

OK, can you indicate what you are taking the voltage readings with?
Are its batteries OK? Have you taken past readings that concur with the manual?

Measurements taken with a high quality multimeter. When I replaced the batteries last month I started paying closer attention to the charging profile and noted the discrepancies. The batteries get sufficient charge from the alternator but just curious why the battery charger voltage is consistently low.

 

[KnotYet]

Measurements taken with a high quality multimeter. When I replaced the batteries last month I started paying closer attention to the charging profile and noted the discrepancies. The batteries get sufficient charge from the alternator but just curious why the battery charger voltage is consistently low.

I infer from your answer that in the past you haven't seen the voltage spec'ed in the manual.
It would be helpful to know if the charger has ever put out the
manual spec voltage or if it is doing what it always has done.

I don't know that charger but there may be an internal adjustment
that the factory may be able to help you with.

 

[twistedtree]

In the bulk charge cycle it will take some time to bring the battery up to the target voltage, longer the more discharged the battery. Does the battery never reach 29.0V even if you leave the charger on through the full bulk phase? Does the charger or anything else tell you what the current is?

 

[Wdeertz]

I infer from your answer that in the past you haven't seen the voltage spec'ed in the manual.
It would be helpful to know if the charger has ever put out the
manual spec voltage or if it is doing what it always has done.

I don't know that charger but there may be an internal adjustment
that the factory may be able to help you with.

Valid point, I never previously paid that close attention so it’s quite possible these lower voltages occurred before the recent battery replacement. Will follow up with tech support of battery charger to see if they have any insights.

 

[Wdeertz]

In the bulk charge cycle it will take some time to bring the battery up to the target voltage, longer the more discharged the battery. Does the battery never reach 29.0V even if you leave the charger on through the full bulk phase? Does the charger or anything else tell you what the current is?

Correct, never reaches 29v, maxes at 28.6v for 4 hour absorption then falls to the lower float voltage. There is a current meter on the charger but not sure how accurate it is. Generally at 5A or less as the start batteries never get much power removed.

 

[twistedtree]

Correct, never reaches 29v, maxes at 28.6v for 4 hour absorption then falls to the lower float voltage. There is a current meter on the charger but not sure how accurate it is. Generally at 5A or less as the start batteries never get much power removed.

OK, thanks. Two other thoughts:


- Is there a temp sensor that connects to the batteries? And what is the ambient temp? If the charger is compensating for temperature, the voltage will drop as the temp rises above 25C. Could that explain it?


- As I use LFP batteries more and more I'm realizing how imprecise the voltage metering and regulation is on a lot of devices. +/- 0.1V seems to be good, and +/1 0.2V not at all uncommon. With lead it's not that critical, but with LFP it definitely matters. So it may just not be all that accurate.

 

[Bacchus]

OK, thanks. Two other thoughts:


- Is there a temp sensor that connects to the batteries? And what is the ambient temp? If the charger is compensating for temperature, the voltage will drop as the temp rises above 25C. Could that explain it?


- As I use LFP batteries more and more I'm realizing how imprecise the voltage metering and regulation is on a lot of devices. +/- 0.1V seems to be good, and +/1 0.2V not at all uncommon. With lead it's not that critical, but with LFP it definitely matters. So it may just not be all that accurate.

Good point
Even if no temp sensor present on batty i believe many chargers will then default to the charger ambient temp and adjust V accordingly.

 

[TowLou]

Are the batteries at rest or do you have a load on them while charging?

 

[Wdeertz]

OK, thanks. Two other thoughts:


- Is there a temp sensor that connects to the batteries? And what is the ambient temp? If the charger is compensating for temperature, the voltage will drop as the temp rises above 25C. Could that explain it?


- As I use LFP batteries more and more I'm realizing how imprecise the voltage metering and regulation is on a lot of devices. +/- 0.1V seems to be good, and +/1 0.2V not at all uncommon. With lead it's not that critical, but with LFP it definitely matters. So it may just not be all that accurate.

Twisted tree, I think you “hit the nail on the head”. No I don’t have a battery temp sensor on the start battery. With the current heat wave the ambient temperature where the charger is about 32C so using a normal slope the 0.4v lower voltages seem about right. I had always assumed battery temp sensors were used to calculate increased voltages when temps were below 25c and mistakenly ignored the slope above 25c. Well you know what they say about “AssUMe” ?

As a side note, I reached out to Charles Industry technical support. Received a reply they got out of the marine industry in 2016 and can no longer provide support. Sent me a few links to the old documentation.

 

[twistedtree]

Twisted tree, I think you “hit the nail on the head”. No I don’t have a battery temp sensor on the start battery. With the current heat wave the ambient temperature where the charger is about 32C so using a normal slope the 0.4v lower voltages seem about right. I had always assumed battery temp sensors were used to calculate increased voltages when temps were below 25c and mistakenly ignored the slope above 25c. Well you know what they say about “AssUMe” ?

As a side note, I reached out to Charles Industry technical support. Received a reply they got out of the marine industry in 2016 and can no longer provide support. Sent me a few links to the old documentation.

Perhaps the manual will say how/if they handle temp compensation.


BTW, to your original question, No, chargers don't "wear out". That's true for most all electronics and electrics. They work, until they don't.

 

[Kiwi.]

So my question is do battery chargers wear out?

To answer your question: No. Something else is happening. You are receiving good advice from other contributors.

 

[Mia]

We had much the same issue in our Carver. Could not trace the issue and got tired of pulling our hair out by the root. Front charger worked fine, but rear would not charge at all.

We ended up replacing it finally and have had no issues since.

 

[Turning Point]

I’m just curious. That’s a big charger. How big is your starting bank?

 

[Wdeertz]

I’m just curious. That’s a big charger. How big is your starting bank?

Start bank is two type 31 12v batteries wired in series. 60 amp is probably bigger than needed but it’s what the boat came with. Meter on charger rarely shows over 5-10 amps.