Do I need new leisure batteries? (Victron setup)

[catlotion]

hi everyone.

I'm getting some odd readings from my leisure batteries. They're just under 3 years old. 3 x 115AH Exide lead acid...

I'm not experiencing any issues with power. I use the fridge, tv, laptop and heater regularly. However, the voltage seems really low despite the monitor showing 100%. The boat panel and heater all report about the same voltage.

I have a Victron SmartShunt and Smart Solar MPPT controller connected to a 160w Renogy panel. This is connected all the time and over winter I occasionally motor about and connect to shore power for additional charging.

See attached screenshots. I'm kind of coming to the conclusion that the batteries are on the way out which is a bit disappointing after such a short time. Any thoughts? I know that the SmartShunt measures the net gain/loss from the batteries but seems to conflict with the voltage.

Second screenshot shows voltage in blue (over 30 days) - seems to drop really low...? I've also attached settings from SmartShunt and MPPT controller. I think the settings are ok - I did a fair bit of reading at the time I set them up but happy to be corrected... (note that current draw in first image is because I'd just switched heater on)

thanks,

Toby

 

[wingcommander]

I reckon the best way to confirm is to disconnect each battery, fully charge it and then do a load test on each battery . If you haven't been getting them fully charged you will be slowly killing them . Maybe a conditioning charge will bring them back .I would expect more than 3 years from lead acid. But only if you keep them regularly fully charged. Check the electrolyte if accessible also.

 

[Sandy]

As you have consumed 0.4 Ah then that is why you are showing 100% charged.

You are drawing 5.58 amps hence the voltage is 12.49.

How much charge are you solar panels giving you? You will get that figure from the MTTP.

I'm running a wee spreadsheet to look at the solar panel output. A screenshot of the summary page below.

 

[Boater Sam]

Unless you regularly fully charge and reset the percentage monitor it will tell you lies and you will always ruin batteries because you are not fully charging.
Charge until the current going in is 1% of the rated battery capacity, otherwise they are never fully charged.

 

[Sandy]

Charge until the current going in is 1% of the rated battery capacity, otherwise they are never fully charged.

That would be 3.45 amps!

As the Victron kit is talking to each other via Bluetooth it will look at the figures in their algorithm and deliver a much more nuanced view of fully charged.

 

[KompetentKrew]

I know that the SmartShunt measures the net gain/loss from the batteries but seems to conflict with the voltage.

In the settings you have "Synchronise State of Charge to 100% on Reset" enabled.

Let's say you're doing stuff on the electrical system - the batteries are at 80% and you disconnect the Smart Shunt; when you reconnect it the SmartShunt will now say 100%. Now you run it down 20% more - the Smart Shunt says 80%, but it's really at 60%. Do you see where I'm going with this? I killed my batteries this way, thinking they were well charged,

This is potentially a very dangerous setting, and it used to be the default - they upgraded the firmware within the last year or two. When you press on where it says "Set to 100%" you will see there are three options, but there used to be only 2 (see this screenshot) and set to 100% was the default.

 

[William_H]

OP should check voltage at the battery terminals. Compare this to the voltage measured by the system. This may show up a volt drop in wiring etc. ol'will

 

[catlotion]

Thanks everyone.

Couple more screenshots showing recent solar input (pretty rubbish in winter)

Also full csv attached.

Need to check electrolyte levels tomorrow as I think they're low maintenance rather than no maintenence...

I never really disconnect anything so I think the sync setting should be OK. I've occasionally manually reset to 100% after being on shore power overnight though...

 

[Neeves]

As you have consumed 0.4 Ah then that is why you are showing 100% charged.

You are drawing 5.58 amps hence the voltage is 12.49.

How much charge are you solar panels giving you? You will get that figure from the MTTP.

I'm running a wee spreadsheet to look at the solar panel output. A screenshot of the summary page below.

View attachment 173462

Interesting data,

What size, watts, are the panels? Are they all the same or do you have different sizes?

Jonathan

 

[catlotion]

Just the one 160w renogy mono panel.

I did have a 100w flexible too but don't leave it on in winter as it's prone to blowing off...

 

[Sandy]

Interesting data,

What size, watts, are the panels? Are they all the same or do you have different sizes?

Jonathan

The panels are 2 * 100 watts.

They are currently only placed on the deck thus not ideally positioned for maximum power generation. Added to that it has been a wet, overcast winter in Cornwall and they are there to keep the batteries topped up between visits.

Once we get on the water and are sailing I be far more active in positioning them for maximum power generation.

 

[catlotion]

Ah sorry, thought that question was for me!

 

[Sandy]

Ah sorry, thought that question was for me!

It is an internet forum, anybody can chip in.

One of the great things of a forum like this is the sharing of knowledge, although at times hard to find in the amount of complete rubbish 'noise' that people post.

 

[Sandy]

OP should check voltage at the battery terminals. Compare this to the voltage measured by the system. This may show up a volt drop in wiring etc. ol'will

The Victron kit is very, very accurate, especially if you fit their Smart Battery Sense directly onto a battery bank. This wee device also feeds the temperature into the their charging algorithm.

 

[catlotion]

The Victron kit is very, very accurate, especially if you fit their Smart Battery Sense directly onto a battery bank. This wee device also feeds the temperature into the their charging algorithm.

hmmm don't have one of those. The MPPT talks to Smart Shunt for voltage though. Is it worth getting the Smart Sense just for temperature?

 

[Neeves]

The panels are 2 * 100 watts.

They are currently only placed on the deck thus not ideally positioned for maximum power generation. Added to that it has been a wet, overcast winter in Cornwall and they are there to keep the batteries topped up between visits.

Once we get on the water and are sailing I be far more active in positioning them for maximum power generation.

Thanks Sandy

I had wondered where the Celtic fringe was - now I know.

Catlotion - I was not ignoring you - thought you had enough to cope with without answering mundane questions. I had a vaguely similar problem and took the battery, engine start, to a battery retailer (thinking I needed a replacement) he tested it and found it perfectly adequate - I took it home rewired it and checked connections - a relay was loose - been fine ever since. I was lucky to have an honest retailer.

 

[Sandy]

hmmm don't have one of those. The MPPT talks to Smart Shunt for voltage though. Is it worth getting the Smart Sense just for temperature?

It is a personal choice. When installing the system I was 'given' it as part of the deal - they retail for under £50.

If you are hammering your batteries and want to get every microamp of charge from your panels then yes. I am often sailing for a month and rarely visit marinas. At other times the boat lives on a mid river mooring with no shore power.

 

[William_H]

The Victron kit is very, very accurate, especially if you fit their Smart Battery Sense directly onto a battery bank. This wee device also feeds the temperature into the their charging algorithm.

Not really doubting Victron accuracy although always worth checking. However a meter to actual (lead) posts of battery rules out bad battery connection. ol'will