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LRD414
29th March 2017, 09:17 PM
I have a Ctek MXS 5.0 and every so often charge the D4 batteries overnight.
I have a Traxide system - SC80 isolator between crank & Optima yellowtop aux 55Ah.

Had the doors open and lights on a lot over the weekend doing stuff and got a dash warning which I think happens at 12.2V
So charged overnight last 4 nights in a row and used the iiD tool to read battery SoC as recorded by the vehicle BMS each morning.

All SoC measurements with D4 running and remaining constant over a 40 minute drive:

26/3 - 60% (due to weekend activities)
27/3 - 74% (after o'night charge)
28/3 - 78% (after o'night charge)
29/3 - 83% (after o'night charge)
30/3 - 86% (after o'night charge)

Now each of the charging nights was around 9-10 hours continuous and at least 8 hours on FLOAT.

I always thought FLOAT meant the battery was fully charged before the charger went to that mode.
But these SoC figures suggest otherwise.

I realise that the SoC could be incorrect due to having an aux battery connected into the system.
Could that be why the SoC is not higher after 8 hours of float?

I don't think anything is wrong or of concern here, I am simply interested in what is going on with the BMS SoC reading.
Is it real or skewed by the aux battery which is like a 50% increase in battery capacity or by the battery charging?
And if so why because surely float mode would apply to the entire connected load of both batteries.

Regards,
Scott

Grentarc
30th March 2017, 12:37 PM
I always thought FLOAT meant the battery was fully charged before the charger went to that mode.
But these SoC figures suggest otherwise.



According to the manual, it cuts over to float once 80% SOC is reached

LRD414
30th March 2017, 01:20 PM
According to the manual, it cuts over to float once 80% SOC is reached
Not according to the manual I have Justin, which I've attached.

It shows:
Bulk mode up to 80% SoC
Absorbtion mode up to 100% SoC
and then into Float mode.

Have you read a document that says different?

Cheers,
Scott

Grentarc
30th March 2017, 04:47 PM
Sorry I misread the Absorbtion as a type of float, didn't read on to see Float is a separate setting.

If you isolate the crank and aux batteries, then charge the crank, what does the charger do?

Tombie
30th March 2017, 08:00 PM
How old is your primary?

scarry
30th March 2017, 08:08 PM
Have the same charger,do mine every few weeks as well.

I always used to charge them both together,with mixed results.

I find charging the batteries separately is by far the best way to do it.

I have a switch on the negative wire from the SC80 so i can isolate the batteries when ever i want to.

i have the Ctek plug permanently wired onto the start battery,poking out through a small cut i put in the plastic battery cover,so it is easy to charge,don't have to take plastic cover off battery,just plug in the charger.

i use the alligator clips on the Optima battery posts.

I also try to leave it on 24hrs on each battery,so they get a good charge and float.

LRD414
30th March 2017, 08:09 PM
Crank battery is 2.5 years old plus however long it took to get here from factory.

scarry
30th March 2017, 08:25 PM
Crank battery is 2.5 years old plus however long it took to get here from factory.

Charge it separately and see how you go.

Or get the dealer to check it,should be under warranty

LRD414
30th March 2017, 08:36 PM
I already have the ctek lead on the crank exactly like you and this is how I charge now, although with SC80 linked. A switch on the SC80 neg is a good idea but as an interim presumably I can just disconnect the SC80 neg cable from earth post? Is the switch directly in line, no relay?

Perhaps the mixed results you've seen and I may be experiencing are due to using a small charger and two different battery types together. I can't really leave it on for 24 hours much due to being driven every week day and most weekends.

Scott

drivesafe
30th March 2017, 09:00 PM
Hi Scott, and your results are exactly what you should be seeing.


But first, prior to starting your charging test, did you do a lot of short drives, and I mean over say the last few months?


If so, then you have been slowly reducing the USABLE battery capacity.


Then by charging every night, the FLOAT portion of the charge cycle has been slowly recovering lost battery capacity.


If you use a digital multi meter to measure the voltage in the morning, you will probably get a fully charged indication.


This is partially correct. The voltage reading relates to the State of Charge ( SoC ) for amount of USABLE battery capacity available, not for the original total capacity.


Whereas, your BMS is relating to the percentage of battery capacity available, based on the original total battery capacity.


Both results are accurate and can be used together to keep an eye on you battery capacity over the lifespan of the battery.


A suggestion for you, keep carrying out your nightly chargers and see how close to 100% you can get.


BTW, your overnight cycles are actually much more effective than just leaving the charger on continually.


Also, there is no need to separate the batteries while you charge them. They will both eventually reach the maximum state of charge independent of one another even while connected together while charging.

Crofty
30th March 2017, 09:10 PM
Hi Scott, and your results are exactly what you should be seeing.


But first, prior to starting your charging test, did you do a lot of short drives, and I mean over say the last few months?


If so, then you have been slowly reducing the USABLE battery capacity.


Then by charging every night, the FLOAT portion of the charge cycle has been slowly recovering lost battery capacity.


If you use a digital multi meter to measure the voltage in the morning, you will probably get a fully charged indication.


This is partially correct. The voltage reading relates to the State of Charge ( SoC ) for amount of USABLE battery capacity available, not for the original total capacity.


Whereas, your BMS is relating to the percentage of battery capacity available, based on the original total battery capacity.


Both results are accurate and can be used together to keep an eye on you battery capacity over the lifespan of the battery.


A suggestion for you, keep carrying out your nightly chargers and see how close to 100% you can get.


BTW, your overnight cycles are actually much more effective than just leaving the charger on continually.


Also, there is no need to separate the batteries while you charge them. They will both eventually reach the maximum state of charge independent of one another even while connected together while charging.

Hi Tim, can you confirm charging both batteries via the 50amp at the rear without changing any configuration is also safe?
Much easier than opening up the bonnet...
Cheers, Andrew

drivesafe
30th March 2017, 09:15 PM
Hi Andrew and yes, you can use either a battery charger or solar panels, via a solar regulator for 20w or larger solar panels, to fully charge both batteries.

Crofty
30th March 2017, 09:18 PM
Hi Andrew and yes, you can use either a battery charger or solar panels, via a solar regulator for 20w or larger solar panels, to fully charge both batteries.

Beauty, thanks for confirming!
Sorry for the hijack Scott [emoji38]

LRD414
30th March 2017, 09:19 PM
Ok that's good Tim. It's just the charger saying float mode confused me a little because I assumed it would't get there until fully charged. Is the charger sensing "useable capacity" and then going to float mode kind of early, followed by time on float increasing usable capacity slowly ?

Scott

Crofty
30th March 2017, 09:26 PM
Guys I don't have the ctek but purchased the power train 12amp charger from Australian Direct.

Power Train 12 Amp 12 Volt 7 Stage Smart Battery Charger (http://www.australiandirect.com.au/buy/SDPTC12V12A7SL)

Do you know if this is a worthwhile charger to continue using or should I bin it and go ctek or other?

drivesafe
30th March 2017, 10:07 PM
If it is working OK don't bin it, just use it.

BTW, if you set it to Lead Acid - AGM, you can safely charge all types of batteries with the one setting.

LRD414
30th March 2017, 10:12 PM
So the timing of going to float mode is related to usable capacity at that time and extra time in float repeated each night is increasing the usable capacity progressively back to full capacity. And is the BMS sensing only the crank battery SoC being on its neg lead.

Scott

Crofty
30th March 2017, 10:14 PM
If it is working OK don't bin it, just use it.

BTW, if you set it to Lead Acid - AGM, you can safely charge all types of batteries with the one setting.

Cheers Tim. To be honest I need to do regular checks to confirm that.

Ive used it every 4 weeks for 3 nights in a row for roughly 8hrs a session.
Without doing measurements all seems to be happy on a car that does roughly 60kms a day.