Charging Trojans

[MtB]

On 12/03/2017 at 23:12, dmr said:

Oh dear, this is all a bit inconclusive, so many experiments end up in the inconclusive region. Both your SGs and resting voltages indicate a state of charge of about 60% (58-61) rather than 50% based on my graphs constructed from the Trojan datasheet. So your smartguage is not quite right but not disastrously wrong (but you have said its volts are a bit wrong...is this in the expected direction....I need to go back through your posts).  You took out about 25amphour which is about 11% of the total capacity. So the big unknown is what was the actual state of charge at the start of your experiment....was the Smartgage equally wrong or not???? If the Smartgage was actually correct at the start of your test then the figures start to look okish, you need to do this all again measuring volts and sg at the start and end of the discharge, and discharging over a bigger range......how tedious.

..............Dave

 

Yes this is obvious, but only since you said it

I'll plan it.

I also noted the other day that I took out 40AH to reduce the battery from 100% to 50%, according to the smartG. Even if the batts are 60% when the smartG is reading 50%, this still suggests a batt capacity of only 100ah against a badge capacity of 225ah.

Today I remembered to bring my other smartgauge back from the other boat. I'll install it in parallel with the existing one. That should show up any differences in sharp contrast!!

[WotEver]

Quote

After isolating the batts and resting them for 30 mins

I wonder how much they recovered in 30 mins. Was the Smartgauge still connected? Was it still displaying 50%?

[nicknorman]

So you have converted pretty much 50% of the sulphuric acid into something else (lead sulphate, presumably). This causes a certain number of electrons to be mobilised. And yet you only seems to have about half the expected number of electrons passing out of the batteries. The simplest explanation for this is that you are not in fact recording all the current leaving the batteries, due, for example, to having the engine battery negative connected directly to the domestic battery negative. I suggest that Occam's Razor applies!

[rusty69]

1 hour ago, nicknorman said:

. I suggest that Occam's Razor applies!

If only Mr Pirsig had written a book about battery maintenance instead  ZATAOMM

[nicknorman]

42 minutes ago, rusty69 said:

If only Mr Pirsig had written a book about battery maintenance instead  ZATAOMM

Very true!

[WotEver]

1 hour ago, rusty69 said:

If only Mr Pirsig had written a book about battery maintenance instead  ZATAOMM

I used to really enjoy fixing my many bikes in the past but I was never very philosophical about it, other than knowing that if something could break then it probably would, at some point or other. 

[rusty69]

2 minutes ago, WotEver said:

if something could break then it probably would, at some point or other. 

I think that's another law.

Usually in the middle of nowhere if my bikes were anything to go by. 

[MtB]

On 13/03/2017 at 07:49, nicknorman said:

So you have converted pretty much 50% of the sulphuric acid into something else (lead sulphate, presumably). This causes a certain number of electrons to be mobilised. And yet you only seems to have about half the expected number of electrons passing out of the batteries. The simplest explanation for this is that you are not in fact recording all the current leaving the batteries, due, for example, to having the engine battery negative connected directly to the domestic battery negative. I suggest that Occam's Razor applies!

 

I agree Mr Occam invented a very useful tool I I use it constantly at work. 

But in this case no the engine battery negative is on the other side of the shunt to the domestic battery negative if that's what you mean, so I think I am correctly recording all the traffic in and out of the domestic batteries.

Using Mr Occams handy tool again, I'd say the most likely explanation is the batteries are trashed and down to 50% of their new capacity, which is what I thought in the first place.

[MtB]

Oh but that doesn't account for the good(ish) SG readings when fully charged.

Perhaps the batteries are not actually 225ah as claimed straight from the factory. This seems unlikely but then perhaps Holmes' Law comes into play instead.

Edited March 13, 2017 by Mike the Boilerman

[WotEver]

6 minutes ago, Mike the Boilerman said:

Oh but that doesn't account for the good(ish) SG readings when fully charged.

Precisely. 

Your fully charged SG readings indicate that they're not sulphated yet your Ah readings to get to 60% SoC indicates low capacity. 

[nicknorman]

10 minutes ago, Mike the Boilerman said:

 

Using Mr Occams handy tool again, I'd say the most likely explanation is the batteries are trashed and down to 50% of their new capacity, which is what I thought in the first place.

But that doesn't fit the facts. Each molecule of h2so4 moves an electron (or is it 2?) when it changes to lead sulphate. So bearing in mind you have used up nearly half the acid, where did the electrons go? Does not compute!

Do you have the correct shunt for the meter settings?

[MtB]

On 13/03/2017 at 10:30, nicknorman said:

But that doesn't fit the facts. Each molecule of h2so4 moves an electron (or is it 2?) when it changes to lead sulphate. So bearing in mind you have used up nearly half the acid, where did the electrons go? Does not compute!

Do you have the correct shunt for the meter settings?

 

I don't know for sure but probably, yes. 

It was a brand new Victron BMV702 and the shunt came in the box with it. Quite a complicated-looking shunt (compared to most) with a bit of electronics attached.

[MtB]

On 13/03/2017 at 10:28, WotEver said:

Precisely. 

Your fully charged SG readings indicate that they're not sulphated yet your Ah readings to get to 60% SoC indicates low capacity. 

 

Yes so maybe we are getting close to why my Trojanoids were a bit cheaper than the real thing. Yuasa have frigged the spec measuring.

The label on each says 225ah (20hr) but only on the removable caps. no model number on the actual batteries, I just checked. 

There IS however a big label bearing a serial number, along with a "recharge date", marked as "17/08". Now if that means week 17 of year 2008, I've been sold seriously old stock batts. 

[mross]

or sell by August 2017 said the optimist!

[smileypete]

41 minutes ago, nicknorman said:

But that doesn't fit the facts. Each molecule of h2so4 moves an electron (or is it 2?) when it changes to lead sulphate. So bearing in mind you have used up nearly half the acid, where did the electrons go? Does not compute!

Do you have the correct shunt for the meter settings?

Could also be underfilling if they're delivered to the supplier empty of electrolyte.

Thing is people rarely correcty check the levels on delivery (if ever!) and record the inital S.G. I s'pose that's another factor in favour of sealed cheapies.

Edited March 13, 2017 by smileypete

[Naughty Cal]

2 hours ago, smileypete said:

Could also be underfilling if they're delivered to the supplier empty of electrolyte.

Thing is people rarely correcty check the levels on delivery (if ever!) and record the inital S.G. I s'pose that's another factor in favour of sealed cheapies.

Would that not have been noticable when the batteries were first delivered though?

From what I understand the batteries were fine when fitted but have had a severe decline over the winter.

[mrsmelly]

2 hours ago, smileypete said:

Could also be underfilling if they're delivered to the supplier empty of electrolyte.

Thing is people rarely correcty check the levels on delivery (if ever!) and record the inital S.G. I s'pose that's another factor in favour of sealed cheapies.

oh how I luv my sealed cheapies.................

[Naughty Cal]

8 minutes ago, mrsmelly said:

oh how I luv my sealed cheapies.................

We are yet to love our newly fitted set of sealed "cheapies." They are still proving to be a little on the sluggish side.

If things don't improve in the next few weeks then they are going back to the supplier!

[rusty69]

1 hour ago, mrsmelly said:

oh how I luv my sealed cheapies.................

Just bought my first AGM, expensive for me - 85 quid

[rusty69]

1 hour ago, Naughty Cal said:

We are yet to love our newly fitted set of sealed "cheapies." They are still proving to be a little on the sluggish side.

If things don't improve in the next few weeks then they are going back to the supplier!

Are they leaving a little silver trail behind them?

[MtB]

23 minutes ago, rusty69 said:

Just bought my first AGM, expensive for me - 85 quid

 

This seems a little unlikely, AGMs are usually nosebleed money. Which make and model did you buy and from whom? I might try some too!!

[Naughty Cal]

12 minutes ago, rusty69 said:

Are they leaving a little silver trail behind them?

Not quite 

[rusty69]

7 minutes ago, Mike the Boilerman said:

 

This seems a little unlikely, AGMs are usually nosebleed money. Which make and model did you buy and from whom? I might try some too!!

12V Leoch 110ah AGM Leisure Battery - LAGM 110L - but it was collection from Peterborough

 

http://www.ebay.co.uk/itm/12V-Leoch-110ah-AGM-Leisure-Battery-Deep-Cycle-Battery-5-year-warranty-/252785548414?hash=item3adb315c7e:g:v6cAAOSwFc5XwAN4

 

Probably carp,I guess time will tell if they are any good,also non standard terminal fittings which I haven't figured out yet

Edited March 13, 2017 by rusty69

[WotEver]

Quote

• 110Ah capacity at C100hr rate

Ahem...

 

7 minutes ago, rusty69 said:

12V Leoch 110ah AGM Leisure Battery - LAGM 110L

 

[cuthound]

2 minutes ago, WotEver said:

Ahem...

 

Beat me to it. The capacity will be considerably less at the C20 rate.

In my previous industry new batteries were tested at the 10 hour rate to verify capacity as part of the acceptance tests. 

Edited March 13, 2017 by cuthound
To unmangle the effects of autocorrect.