Battery conundrum

[GUMPY]

So left the mooring 2 days ago after having been on float (13.5v) for a while with the occasional cycle of tbe charger.

Stopped the 1st night after 6hrs cruising, woke up next morning SG showing 89% voltage with no load 12.6v

Inverter wouldn't switch out of standby and voltage when waterpump running was 11.5v.

Not what you need on first day of holiday

10hrs cruising next day with much panic as to where will I source new batteries at a sensible price.

Stopped last night and after a couple of hours decided to check each battery independently all were 12.95 with no load and 12.9v under waterpump load.

This morning 89% and again less than 0.05v drop with waterpump on.

Because they are sealed calcium I haven't been able to do an equalizing charge every couple of months when at home so I suspect that capacity had been reduced, which oddly SG didn't report, and the 10hrs at 14.4v has improved matters.

Batteries are 4 years old and have spent most of that on float....

What does the panel think?

[WotEver]

10hrs at 14.4V will have stirred up the electrolyte a bit and removed a bit of Sulphation. Do that a few more times and see how you get on.

 

SG won't report loss of capacity - it has no way of knowing that - it'll only tell you how charged they are as a percentage of whatever capacity they have.

[Richard10002]

10hrs cruising next day with much panic as to where will I source new batteries at a sensible price.

Stopped last night and after a couple of hours decided to check each battery independently all were 12.95 with no load and 12.9v under waterpump load.

This morning 89% and again less than 0.05v drop with waterpump on.

 

So, on the second morning, the batteries seem fine? 12.6V no load, 12.55V with waterpump?

 

I wonder if they were not as fully charged as you thought when on shore power on the mooring, and a couple of days motoring have sorted them out, (for a while).

 

Given that you will probably be cruising daily to give enough power for your evening, and you will need to cruise towards where you are going to buy new batteries, I would see how it goes over a few days.

[nicknorman]

I find batteries weak / low capacity on the 1st discharge after a long period on float. However yours does seem an extreme example. Are you sure there isn't/ wasn't a high resistance connection eg at the isolator?

 

Going from 12.6 to 11.9 with modest load surely points to voltage drop somewhere?

Edited August 27, 2016 by nicknorman

[bottle]

So left the mooring 2 days ago after having been on float (13.5v) for a while with the occasional cycle of tbe charger.

Stopped the 1st night after 6hrs cruising, woke up next morning SG showing 89% voltage with no load 12.6v

Inverter wouldn't switch out of standby and voltage when waterpump running was 11.5v.

Not what you need on first day of holiday

10hrs cruising next day with much panic as to where will I source new batteries at a sensible price.

Stopped last night and after a couple of hours decided to check each battery independently all were 12.95 with no load and 12.9v under waterpump load.

This morning 89% and again less than 0.05v drop with waterpump on.

Because they are sealed calcium I haven't been able to do an equalizing charge every couple of months when at home so I suspect that capacity had been reduced, which oddly SG didn't report, and the 10hrs at 14.4v has improved matters.

Batteries are 4 years old and have spent most of that on float....

What does the panel think?

 

 

10hrs at 14.4V will have stirred up the electrolyte a bit and removed a bit of Sulphation. Do that a few more times and see how you get on.

 

SG won't report loss of capacity - it has no way of knowing that - it'll only tell you how charged they are as a percentage of whatever capacity they have.

 

Technical answer from WotEver, me being a simple soul would say think of a bucket and water.

 

When the bucket is new it can be filled to the top but as it ages, gunge etc. collects in the bottom, the bucket can be filled to the top still but does not have the same capacity.

 

The bucket is full but...

 

The Smartgauge will still tell you the bucket battery is full but it does not know how much gunge is in the bottom.

 

The Smartgauge will still tell you a true usage of the the available capacity.

 

When you notice that the batteries do not last as long and you are charging them more often (same usage) then it is a good indicator that the batteries are on there way out.

[GUMPY]

Yes I do understand SG ( for the record I had one of the early prototypes for testing) only reports available capacity it would however need a cycle or so to work it out so if capacity dips (as it did) and then recovers it wouldn't see it.

Nicks theory about bad joint could be possible but unlikely as I did disconnect the links on the batteries but not the feeds to the system.

Still Ill see how it goes it has happened before after a period on float but never this bad and SG did report it last time by showing a reduced % reading. Oh I also got an 02 error on the first day but tbats just low volts for battery type.

[ditchcrawler]

Yes I do understand SG ( for the record I had one of the early prototypes for testing) only reports available capacity it would however need a cycle or so to work it out so if capacity dips (as it did) and then recovers it wouldn't see it.

Nicks theory about bad joint could be possible but unlikely as I did disconnect the links on the batteries but not the feeds to the system.

Still Ill see how it goes it has happened before after a period on float but never this bad and SG did report it last time by showing a reduced % reading. Oh I also got an 02 error on the first day but tbats just low volts for battery type.

Have you borrowed Rivet's curly lead?

[GUMPY]

Have you borrowed Rivet's curly lead?

No but I could do with it

[Tony Brooks]

Pay special attention to the domestic negative busbar, especially if it s inside a fuse/MCB box. If any screws are even a bit loose they can give all sorts of odd problems.

[Detling]

Now't to worry about. My Smartgauge takes a day or two to get back into the rhythm of life when I leave the marina, I recon day after day of no loads, no cycle of voltage seems to put it to sleep. Usually day one it under estimates the status (reads low) next day it reads high and by day 4 is on the button all the time. I have never checked the voltages though as I have never seen the need to bother. Morning one will state 75%, morning two 85% and morning three 80% same useage overnight, stopping each day at 100% and I certainly am not concerned at 75% as it is way over the 50% level. Only when stopping for a few days will I see below 60% readings.

I have never seen the water pump or shower pump drop the voltage on the smartgauge or the voltmeter I have connected to the domestic batteries both are connected to the batteries by their own leads and do not share a lead with any load, it sounds as though maybe someone has connected the smartgauge to a convenient point near to it which just happens to also connect the water pump and is several feet from the battery bank, and not directly to the battery terminals via it's own fuse as stated in the manual

[WotEver]

If the SG isn't connected directly to the battery posts then you might as well throw it in the cut. It will be if no use whatsoever connected anywhere else.

[bottle]

Yes I do understand SG ( for the record I had one of the early prototypes for testing) only reports available capacity it would however need a cycle or so to work it out so if capacity dips (as it did) and then recovers it wouldn't see it.

Nicks theory about bad joint could be possible but unlikely as I did disconnect the links on the batteries but not the feeds to the system.

Still Ill see how it goes it has happened before after a period on float but never this bad and SG did report it last time by showing a reduced % reading. Oh I also got an 02 error on the first day but tbats just low volts for battery type.

 

Thought you did, my post was just in case someone else did not.

 

Maybe someone with a similar problem and doing a search.

[GUMPY]

Just for info of course SG is direct to the posts do you really think I am that stupid!

Last night watched Three hours if tv/pvr inverter refused this morning at 0700 with SG reading 82%.

My conclusion is that because the batts are likely to be at less than 50% of their origional capacity SG is telling lies.

So I hope to get some Crown DC130 in Leicester on Wednesday meanwhile cut back on bat usage as much as poss

[Tony Brooks]

Just for info of course SG is direct to the posts do you really think I am that stupid!

Last night watched Three hours if tv/pvr inverter refused this morning at 0700 with SG reading 82%.

My conclusion is that because the batts are likely to be at less than 50% of their origional capacity SG is telling lies.

So I hope to get some Crown DC130 in Leicester on Wednesday meanwhile cut back on bat usage as much as poss

 

No the Smartguage is very unlikely to be telling lies. As has been explained it shows the remaining charge as a percentage of THE PRESENT BATTERY CAPACITY NOT THE ORIGINAL CAPACITY. This tend to support the theory that you have been consistently undercharging it.

 

Lash out on an ammeter and stop charging by tail current and ignore the Smartguage until after charging has stopped.

 

 

[MtB]

Just for info of course SG is direct to the posts do you really think I am that stupid!

Last night watched Three hours if tv/pvr inverter refused this morning at 0700 with SG reading 82%.

 

By inverter refusing, what do you mean? The inverter displays a "low battery voltage" error message or something?

 

I'd be measuring battery post voltage and comparing it with inverter input terminal voltage while the error massage is present. I hear repeated stories of people jumping to conclusions and buying new batteries unnecessarily.

[bottle]

Just for info of course SG is direct to the posts do you really think I am that stupid!

Last night watched Three hours if tv/pvr inverter refused this morning at 0700 with SG reading 82%.

My conclusion is that because the batts are likely to be at less than 50% of their origional capacity SG is telling lies.

So I hope to get some Crown DC130 in Leicester on Wednesday meanwhile cut back on bat usage as much as poss

 

Just for the record, I do not think you stupid.

 

As for the bit in red, isn't that somewhere in the manual.

[GUMPY]

Indeed it may be.

I just didn't realise just how screwy the readings would be.

97% overnight with fridge and inverter on that means the fridge can only have run fir one hour in twelve.

Did a quick test this morning

Managed 4 minutes with the immersion on

% dropped by 10

Voltage plummeted

My rough calcs make a 375ah bank down to 100ah........

[WotEver]

 

As for the bit in red, isn't that somewhere in the manual.

Not sure it's in the manual but I do recall it being written in typical Gibbo style as "A battery at less than 50% capacity is broken. SmartGauge doesn't measure broken batteries."

[GUMPY]

Not sure it's in the manual but I do recall it being written in typical Gibbo style as "A battery at less than 50% capacity is broken. SmartGauge doesn't measure broken batteries."

That sounds about par.

wasn't there a user on here that had a long running "debate" with Gibbo over his batts not being broken and SG was?

[WotEver]

That sounds about par.

wasn't there a user on here that had a long running "debate" with Gibbo over his batts not being broken and SG was?

Lots of folk have done that. They have all been wrong.

[bottle]

Not sure it's in the manual but I do recall it being written in typical Gibbo style as "A battery at less than 50% capacity is broken. SmartGauge doesn't measure broken batteries."

 

I was not sure either but thought I had read it somewhere, probably as you say one of Gibbo's posts.

[GUMPY]

All change.

The batteries have been changed now have 3x130ah traction bats

500 cycles to 80%dod not that they will get anywhere close to 80%

SG reset to factory defaults and then set up

Charger resetup and doing its thing (in Market Harborough £10 mooring and free elec)

Just need to tweek alternator to 14.8v from 14.4v

Will see how we go from here.

 

Batts came from

https://www.batteryservicehub.com/

Nice people good price.

[nicknorman]

All change.

The batteries have been changed now have 3x130ah traction bats

500 cycles to 80%dod not that they will get anywhere close to 80%

SG reset to factory defaults and then set up

Charger resetup and doing its thing (in Market Harborough £10 mooring and free elec)

Just need to tweek alternator to 14.8v from 14.4v

Will see how we go from here.

Batts came from

https://www.batteryservicehub.com/

Nice people good price.

What make/ model of batteries?

[MtB]

They are silly billies not having prices on their web site (as far as I can see on the mobile version).

[GUMPY]

What make/ model of batteries?

Without lifting floor I can't remember

Recipt just gives part number.