Googled Varta LFD90 to death but..

[Insider]

Hi,

In the middle of installing 2xVartaLFD90s in my van. Everyone swears by them for a whole variety of reasons(researched extensively) but no one(manufacturer included) seems to have a charge profile available. Maybe I'm after failing miserably in my searching but I just want to know how to program a Victron75/15 to deliver the correct voltages for the correct length of time. Many rosaries will be offered to the person who subtly points out how stupid I am in a nice but utterly non PC way ;-)

TIA

Rory

 

[Fletton]

I've had these settings on my pair of LFD90's without issue since I installed them back in Jan 2017..

 

[StephDeLux]

They are high quality flood batteries. Ideally they should get the same profile as normal flood batteries. Some van are built with chargers that don't have that profile anymore. Second best would be a gel profile because it uses the same tension (14.4V). Potential problem is that the gel profile will apply that tension far too long for a flood battery. Maybe the LFD can take it, but I have no idea. In any case, do not apply an AGM profile. That will send 14.7V to the battery, definitely too high.

 

[Insider]

So - I'm putting in 2 LFD90s and ignore the settings above in the pictures as I took the screenshot early on in the process. I have 3 steps to worry about - bulk, adsorption and float. The victron has no bulk setting other than"Re-bulk voltage offset" in expert mode. Bit confused about that and would like to hear why it's not included or I'm incorrectly interpreting the expert mode and the victron is adding the 0.4V to the adsorption mode and bring it to 14.8V which I understand is ideal for a Lead Acid battery.

On to the adsorption mode - Fletton used 14.4V here. This seems correct - the process of adsorption is to bring it from 80% to ca 90% and in expert mode there is a maximum time of 6hrs. I'll leave that but given I'll have 2 batteries does anyone recommending increasing the time period?

Float at 13.5V in Fletton's screenshot seems to be just a tad too high perhaps. I have come across a recommended 13.2 to 13.4V. Again given that this battery seems to be used a lot I would have expected to come across more ancedotal references.

Equilization I'm happy to leave at 14.4V but also happy to leave it to manual. My understanding that this is something that puts most stress on the battery and given that these batteries are in the inside of a camper it is something that should be done manually and with a lot of observation given to the temperature etc while it is being done.

All this is perhaps a bit of overkill as I have the Victron cabled at the top of the van with a run of 4 to 5m via the Sargent PX300 into battery. The Sargent will have it's own charging profile - optimised for Lead Acid and there is going to be a certain voltage drop - small as it is given the factory wires are not as big as I'd like.

OCD or on the ball?

Thanks in advance!

 

[StephDeLux]

14.8V which I understand is ideal for a Lead Acid battery.

Not at all. This is only OK for AGM batteries. Even for them the ideal tension is 14.7V. 14.8V is too much for flood and gel batteries.

^{_{Subscribers  do not see these advertisements}}

 

[Insider]

Not at all. This is only OK for AGM batteries. Even for them the ideal tension is 14.7V. 14.8V is too much for flood and gel batteries.

Understood - my apologies - I got confused. Bulk should always be 14.4V max for Lead Acid. Turns out the "Re-bulk voltage offset" is a feature whereby if the voltage drops by a set amount - default is 0.4 V it goes from Float to Bulk. That should cover heavy usage in the mid morning I imagine.

 

[Lenny HB]

- the process of adsorption is to bring it from 80% to ca 90% and in expert mode there is a maximum time of 6hrs. I'll leave that but given I'll have 2 batteries does anyone recommending increasing the time period?

For flooded cells like the LDF 1 hour absorption will be enough, although the LDF's are quite tolerant a longer absorption won't hurt them but it's not needed.

 

[Insider]

OK, next stumbling block. I have my 2 LFD90s and they are different weights! The manufacturer technical sheet states 24.6kg. One is 24.7kg, the other one is 24.2kg. That's a sizable difference. Got to go back to the supplier :-(

 

[Lenny HB]

OK, next stumbling block. I have my 2 LFD90s and they are different weights! The manufacturer technical sheet states 24.6kg. One is 24.7kg, the other one is 24.2kg. That's a sizable difference. Got to go back to the supplier :-(

Spec filled weight is 24.6kg lowest one is within 1.6% I would have thought that is more than acceptable.

 

[bigtwin]

Spec filled weight is 24.6kg lowest one is within 1.6% I would have thought that is more than acceptable.

I just did the calculation (before reading your post) and was going to post exactly what you did!

Ian

^{_{Subscribers  do not see these advertisements}}

 

[Insider]

Lenny, Ian, 1.6% is a small difference and this is likely my OCD kicking in. I will bow to your superior knowledge but I had been looking at it in 2 other ways.

1: The weight is still below the manufacturer spec - I would have thought that unusual - these are mass produced to a specific spec.

2: I'm assuming that the weight difference is due to electrolyte. Given that ca 60% of the weight is lead and 15% is the other weight is terminals, case etc that leaves 25% electrolyte. I'm assuming that 75% is very consistent - lead is very very expensive. They all cost money and in modern manufacturing if you're using even 1% too much then your costs are wrong. That gives 6.15kg/4.92L of electrolyte. 400g as a percentage of this is 6.5%

 

[Fletton]

Since 2017..…
And full time...
Think your over thinking this one

 

[AXO66]

Blimey. And i always thought 12v was what was said on the tin.

jokeing apart what actual day to day effect do the difference in the charging voltage and weights make.?

is it something we should all be alive to.?

Or is it something that folks that are fascinated by electrics are concerned about to eek out every last amp? (Bit like a pro cyclist getting that extra 1/2% in performance.)

 

[Insider]

OK - got to agree - I think I'm overthinking on this one with the weights. Shone a light on them and definitely not 500ml difference. Both electrolytes the same height. Back to Lenny and Ian with the 1.6% difference - thanks

 

[bigtwin]

Lenny, Ian, 1.6% is a small difference and this is likely my OCD kicking in. I will bow to your superior knowledge but I had been looking at it in 2 other ways.

1: The weight is still below the manufacturer spec - I would have thought that unusual - these are mass produced to a specific spec.

2: I'm assuming that the weight difference is due to electrolyte. Given that ca 60% of the weight is lead and 15% is the other weight is terminals, case etc that leaves 25% electrolyte. I'm assuming that 75% is very consistent - lead is very very expensive. They all cost money and in modern manufacturing if you're using even 1% too much then your costs are wrong. That gives 6.15kg/4.92L of electrolyte. 400g as a percentage of this is 6.5%

1. Only one of your batteries was below the spec weight; the other was over! Whether 1.6% is within tolerance is a moot point but it’s not one that I’d worry about.
2. A fair point but my guess would be that a significant proportion of the weight difference would be associated with the lead plates (and yes, I acknowledge that this will be the most expensive component and ought to be controlled to a tighter tolerance). Thus, for example, a 0.5% tolerance on the lead, a 10% tolerance on the casing and 5% tolerance on the acid, might lead to an overall tolerance of 1.6%.

The problem with a sample set of only two items is that it’s difficult to judge if either item is an outlier.

Ian

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

Also what did you weigh them on?
What is the tolerance of your scales?
When were the scales last calibrated?

 

[Insider]

Lenny - I've had a feeling that the weighing scales is a bit faulty over the last few years.....and not in a good way either!!

Scales is not calibrated but giving reproducible relative readings which was the worry. Small sample set is the killer thou as one makes the other look bad and then you make the assumption that one is right as it's close to the published weight. Throw in that the reading is only displaying one decimal point and do the maths and I could really get some abuse . Reckon the 1.6 could be reduced to under 1%...either way it's placated me and my OC - thanks to all - great forum - now I just need a bit sunshine!!

 

[Helzy]

Hi,

In the middle of installing 2xVartaLFD90s in my van. Everyone swears by them for a whole variety of reasons(researched extensively) but no one(manufacturer included) seems to have a charge profile available. Maybe I'm after failing miserably in my searching but I just want to know how to program a Victron75/15 to deliver the correct voltages for the correct length of time. Many rosaries will be offered to the person who subtly points out how stupid I am in a nice but utterly non PC way ;-)

TIA

Rory

Snap!! I am in the same boat ! I have the varta lfd90 and googled every day for last 3 days Then I found this tell me pleassssse did you find the charge settings ? I have a dc to dc charger which is no use to me atm !!! Please help my madness

 

[Diabalo]

This is the Sargent PX300 charging profile, the info is in resources if interested.

During stage 1 the battery voltage is increased gradually while the current is limited to start the charging process and protect the battery. At stage 2 the voltage rises to 14.4V (Vboost) to deliver the bulk charge to the battery. When the battery is charged, the voltage is decreased at stage 3 to 13.6V (Vflt) to deliver a float charge to maintain the battery in the fully charged state. The charger can be left switched on continuously as required

 

[Lenny HB]

Snap!! I am in the same boat ! I have the varta lfd90 and googled every day for last 3 days Then I found this tell me pleassssse did you find the charge settings ? I have a dc to dc charger which is no use to me atm !!! Please help my madness

Stanrd setting for a sealed lead acid should be fine.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

This is the Sargent PX300 charging profile, the info is in resources if interested.

During stage 1 the battery voltage is increased gradually while the current is limited to start the charging process and protect the battery. At stage 2 the voltage rises to 14.4V (Vboost) to deliver the bulk charge to the battery. When the battery is charged, the voltage is decreased at stage 3 to 13.6V (Vflt) to deliver a float charge to maintain the battery in the fully charged state. The charger can be left switched on continuously as required

What happened to the absorbtion phase?

 

[Diabalo]

Lenny HB no idea that's all it says in the guide about the charging profile, there is a graphic but don't tell you much either.

 

[Lenny HB]

Lenny HB no idea that's all it says in the guide about the charging profile, there is a graphic but don't tell you much either.

Looking at what you posted they appear to have got their terminology wrong.

 

[DBK]

I replaced my LFD90s when they died this year with LED95s. These are the same dimensions so it was an easy swap. A bit more capacity although unfortunately, quite a bit more expensive.

 

[Lenny HB]

Lenny HB no idea that's all it says in the guide about the charging profile, there is a graphic but don't tell you much either.

Looking at what you posted they appear to have got their terminology wrong

^{_{Subscribers  do not see these advertisements}}

 

[Helzy]

I replaced my LFD90s when they died this year with LED95s. These are the same dimensions so it was an easy swap. A bit more capacity although unfortunately, quite a bit more expensive.

I am very disappointed with varta as dispite email and phone message no one has responded. I thought I was being clever installing a victron dc dc 18amp charger in my van ......til I don't appear to be able to charge with confidence my lfd90 ......looks like I need to save for a battery thats in the presets !!

 

[DBK]

I am very disappointed with varta as dispite email and phone message no one has responded. I thought I was being clever installing a victron dc dc 18amp charger in my van ......til I don't appear to be able to charge with confidence my lfd90 ......looks like I need to save for a battery thats in the presets !!

I think you are over-thinking things. These are just basic lead acid batteries.

I suggest contacting Victron, who are quick to reply in my experience, and ask them what profile to use for a flooded wet cell battery.

 

[Helzy]

Thank you Yes overthrowing is likely due to no response Thank you

 

[Helzy]

Over thinking even

 

[autorouter]

What happened to the absorbtion phase?

I think Sargent's description is a bit different to the common accepted description of the 3-stage charging process. Their graphs confirm that it's the standard process, but their description isn't as I expect.

Stage 1 is normally called the bulk stage, but Sargent don't give it a name.
Stage 2 is normally called the absorption stage, but Sargent call it the bulk stage.
Stage 3 is normally called the float stage, and Sargent also call it the float stage.

The high voltage in stage 2 is normally called the absorption voltage, and that's what Sargent call it in the description, but they label it as VBoost in the diagram.

In Stage 1 the charger outputs its maximum current (amps). The charger electronics limits the output amps to the designed maximum, and the voltage gradually rises until it reaches the absorption voltage. At that point the battery is about 80% charged. When it reaches the absorption voltage, the charger flips into Stage 2, the absorption stage.

In Stage 2 the voltage is fixed at a constant voltage, set at the absorption voltage. The amps gradually falls until it has dropped to a predetermined limit, called the tail current, typically about 1/10 of the maximum current. At that point the battery is 100% charged. When the amps drops to the tail current, the charger flips into Stage 3, the float stage.

In Stage 3 the voltage drops to the float voltage, which is just high enough to stop the battery from discharging and keep it topped up, without overcharging. This is a maintenance stage, and in theory the battery can be kept in the float stage indefinitely without deterioration.

The absorption voltage and float voltage are determined by the exact type of the battery. For example, the acid concentration is slightly different for the various battery types, and that's the main thing that determines the float voltage.

AGM and Gel batteries have a recombination reaction, where the hydrogen and oxygen gases recombine under pressure to make water. This process takes quite a long time, so these battery types have an extended timed absorption stage, that flooded batteries do not require.