6v 8GGC2 Battery - is this Gel Cell?

[john61ct]

Annual? [emoji1787]

No, go back and read my posts for how Full is defined, all there, several times.

In MS' accurate BM article he details the proper procedure.

One unit at a time.

Rough version, get your ammeter and DMM, and a DC bulb that draws at a 0.05C rate, if you can use a dimmer to tweak it as V drops even better.

Draw from full to 5.4V and time it, if 100% SoH should take 20hrs, if 17:25 then 87%

Set up a phone to take a photo every X minutes to log the curve if you like.

Do **not** let get lower than 5.4V, and immediately recharge.

If EPM tech support says should equalize now's a good time.

obviously all much easier on shore.

[john61ct]

EoL should be 70-75% SoH

[BigAl.NZ]

Originally Posted by john61ct

Annual? [emoji1787]

No, go back and read my posts for how Full is defined, all there, several times.

In MS' accurate BM article he details the proper procedure.

One unit at a time.

Rough version, get your ammeter and DMM, and a DC bulb that draws at a 0.05C rate, if you can use a dimmer to tweak it as V drops even better.

Draw from full to 5.4V and time it, if 100% SoH should take 20hrs, if 17:25 then 87%

Set up a phone to take a photo every X minutes to log the curve if you like.

Do **not** let get lower than 5.4V, and immediately recharge.

If EPM tech support says should equalize now's a good time.

obviously all much easier on shore.

Well they are GEL batteries so I don't want to equalise them ( https://www.google.com/search?rlz=1C...4dUDCAs&uact=5 )

That procedure you describe is a capacity test. I can full my batteries without a capacity test, but I wont know what that full is (in Ah).

[john61ct]

Originally Posted by BigAl.NZ

That procedure you describe is a capacity test. I can full my batteries without a capacity test, but I wont know what that full is (in Ah).

The cap test tells you what your actual Ah is

which is required to be input for the BM to be accurate.

The 100% Full point, where you reset the BM every cycle, or twice a week or whatever is

""Hold x Absorb V until current tapers down to y amps."

That is all.

[Pete7]

Originally Posted by john61ct

The cap test tells you what your actual Ah is

which is required to be input for the BM to be accurate.

The 100% Full point, where you reset the BM every cycle, or twice a week or whatever is

""Hold x Absorb V until current tapers down to y amps."

That is all.

Except not all battery monitors (BM) need or have the ability to add the capacity. My Sterling BM doesn't and is non the worse for that. Can you show that it doesn't work and that I need to replace it bearing in mind it cost £300?

Originally Posted by john61ct

EoL should be 70-75% SoH

Is this from the battery manufacturers who want you to buy new ones by chance What's wrong in your estimation of going to 60% ? Which I suspect a lot of owners actually do without realising it, only changing when the batteries don't hold sufficient charge for their needs rather than some arbitrary %.


From one of your recent posts,

Originally Posted by john61ct

This really is a switch, when **I'm** the one saying no need to fuss so much, batteries are consumables 8-)

My point exactly

Pete

[john61ct]

Originally Posted by Pete7

Except not all battery monitors (BM) need or have the ability to add the capacity. My Sterling BM doesn't and is non the worse for that.

For some it is a failing, others a fault.

Less accuracy does not mean "doesn't work"

Can you show that it doesn't work and that I need to replace it bearing in mind it cost £300?



Industry standard is 80%

> What's wrong in your estimation of going to 60% ?

Much greater - not linear - risk of sudden unexpected failure, and a less pleasant mode of failure.

[Pete7]

Originally Posted by john61ct

For some it is a failing, others a fault.

Less accuracy does not mean "doesn't work"

True, it could even be telling the absolute truth and there is nothing to worry about nor need to change any settings. I have read Main Sails article as I am sure you have. My personal experience is their isn't a problem with BMs that don't need adjusting or capacity adding, which will change, given the battery life I am getting. This is based on my experience rather than something I read on the internet of course.

Originally Posted by john61ct

Industry standard is 80%. Much greater - not linear - risk of sudden unexpected failure, and a less pleasant mode of failure.

80% hey, well Like I said from the manufacturers, would that increase their turn over by chance? good for the shareholders

My experience of battery failures is that one will go after warning all is not well, then any others in the bank will follow suit rather than all suddenly failing. So as long as you haven't got just one pair in series; stuff will work until you get home. After all most folk are coastal cruising, perhaps with a few overnight passages so should be a problem getting in somewhere.

Haven't tried LFP so don't know what a failure on that battery chemistry is like, but then few probably have.

Pete

[john61ct]

Yes the fact that Ah capacity is constantly declining is exactly why that number must be regularly updated, in order for SoC% to be accurate.

And yes, those traveling to / living in primitive locations should take more care to prevent surprises.

[senormechanico]

Originally Posted by BigAl.NZ

That doesnt quite add up. The manual says (default) 6mV / deg C - so 0.006 * 10 = 0.06 = yet I was getting 14.4 when I had programmed 14.1. I can't account for being a whole 0.2 out when temperature could only be 0.06.

I will check what the SLP factor was set to.

Are you measuring that at the battery posts, or at the alternator output or somewhere in between?

At heavy current, there WILL be differences, the amount depending on wire gauges.

[BigAl.NZ]

Originally Posted by senormechanico

Are you measuring that at the battery posts, or at the alternator output or somewhere in between?

At heavy current, there WILL be differences, the amount depending on wire gauges.

I was measuring at the terminal, but I found I was using the wrong offset per cell. I managed to get a number of about 0.2 which was the offset I was seeing.

[BonesD]

I wonder why anyone would want to charge and use an obviously compromised piece of equipment. Knowing why it failed is more important. Some devices fail due to manufacturing errors, or maybe your charging system has issues and needs looking at to make sure it’s not going to happen again. Either way I would dispose of the offending battery.

[john61ct]

But getting clarity on what the proper care requirements are, and a better understanding of the various factors involved is A Good Thing.

[BigAl.NZ]

As (hopefully) the final chapter in this battery saga, I had a look at the starter alternator (we have two) as it was the only thing left in the charging system that I had not checked to ensure it was compatible with our GEL batteries.

The alternator is a WAI 7186-3N with a single stage built in regulator. It is rated for 65A and is mounted to our Perkins 4.108 which we got from Trans Atlantic Diesels (TAD).

I discovered that it was not putting out anything. When I pulled it apart I found this.

I think that when the battery dropped a cell the house Balmar could cope, but the poor old WAI couldn't put up with trying to charge something that was never going accept enough charge.

Posting this for the knowledge of the community (I am repairing that house Alternator (rectifier, diodes and stators - single stage 14v)).

[john61ct]

Convert your replacement to an external VR like Balmar MC-614 or Wakespeed to give adjustability & precision in tuning output to suit whatever bank chemistries you may wat to use in future.