Lifeline AGM and Victron charging

[Olly75]

I seem to have a problem with my batteries and getting them charged. and I hope someone can give some advice.

I have a victron multiplus 110v connected to a bank of lifeline agm's with 660ah capacity.

Currently when I connect to shore power or charge off the engine for that matter, the batteries reach around 13.80v in bulk in around 10 minutes, then the charger drops into absorption and the current tapers off into float volatage in around an hour. The current then sits around 3 amps trickle charging. On todays cycle, Im now at 87% charge with a 90Ah deficit.

I have connected to VE configure and followed Victrons settings videos but it makes no difference to the charging cycle.
The settings I have are:
State of charge when bulk finished 85%
Absorption voltage 14.27v (its hot here and I took this number from the Lifeline manual)
Float voltage 13.25
Charge current 100A.

As the charger is not reaching any of these voltages should I assume that its just the batteries dying, or have I missed somthing obvious. And even though I cant seem to get them up to a full charge, can I try to condition them (following the lifeline manual) or will this irreperably damage the batteries?

[rslifkin]

What is the Multiplus reporting for battery temperature towards the end of the bulk phase?


Also, if you have any DC loads and the Multiplus isn't the only source of power in and out of the battery, you need a separate battery monitor as the one built into the Multiplus will be wrong (it's unaware of those other loads).

[smac999]

it's not dying batteries. the charger should be able to get the batteries to 14.3v no matter what. unless they were shorted out and taking more then 100a due to the short. but then those would blow up pretty quickly...

when the charger is in bulk measure the voltage at the output of the multi and the battery themselfs. if you have small / bad cables it'll hit 14.3 at the charger output and could cut off to float early though the batteries might only be at 13.8. a 0.5v drop with 100a charger is certainly possible. though an inverter / charger should have huge cables and not much drop.

also since the multi has a battery temp the voltage will be lower if its' really hot. but 0,5v lower is a lot. maybe if it was 40c out. you could unplug the battery temp sensor and see if the batteries hit 14.3v


also if the bank is only taking 3a at float it's probably full and you should reset the meter.

[Olly75]

Interesting...

I also have a victrom smart bmv in the system and a colour control unit networked into the multi.

I just turned it off and back on again to getthe multi back into bulk, albeit briefly (like a couple of minutes) the battery temperature is reading 29C or 84F

In Bulk
Multi 14.3
Batteries around 14.2
Didnt get the chance to check the reading of the smart bmv or the colour control unit before it dropped into absorption.

In absorption
Multi 14.21
Batteries14.09
Both the smart bmv and the colour control unit are reading 13.9.

So should I just ignore the voltage/state of charge at the smart bmv and colour control unit, and use a multi metre to check voltages from now on? Or is there a way to recalibrate them?

[rslifkin]

Try turning on DVCC on the Color Control. You can have the Multi work off the voltage reported by the battery monitor (make sure it's getting its power feed right from the battery positive terminal) instead of its own internal sense. Also make sure that there aren't any ground cables bypassing the shunt for the BMV, as that will cause inaccurate readings.

[s/v Jedi]

Something is wrong with the cabling, probably a high contact resistance somewhere. Where the GX and BMV measure a lower voltage than the battery voltage: check both voltages with the multimeter. Measure at where the BMV connects to as well as on the shunt itself.

It can even be the fuse of the BMV voltage sense wire.

[Olly75]

Hmm, thank you all for the fantastic replies. Im heading out but will investigate properly whan I get to my anchorage....

[SeattleGrandBan]

Did this get resolved - I have the same issue. Victron 3000 multi, goes to float and charges only a few amps (5ish).

[smac999]

Originally Posted by SeattleGrandBan

Did this get resolved - I have the same issue. Victron 3000 multi, goes to float and charges only a few amps (5ish).

goes straight to float when powered on? or goes to float too early after bulk and absorb?

I have had issues with the mulits not going to bulk when ac is applied. the rebulk setting is too low and not adjustable. I now sometimes use the lithuim setting for agm batteries. this changes the rebulk voltage setting and makes the charger go to bulk when the gen is started. the voltage settings are still manually set for the battery type. the only downside is it no longer uses battery temp comp.

[s/v Jedi]

Originally Posted by smac999

goes straight to float when powered on? or goes to float too early after bulk and absorb?

I have had issues with the mulits not going to bulk when ac is applied. the rebulk setting is too low and not adjustable. I now sometimes use the lithuim setting for agm batteries. this changes the rebulk voltage setting and makes the charger go to bulk when the gen is started. the voltage settings are still manually set for the battery type. the only downside is it no longer uses battery temp comp.

Besides AGM or Lithium etc. you can also completely customize battery settings.

Always use the battery manufacturer recommended settings rather than a preset in the charger.

[tanglewood]

Originally Posted by s/v Jedi

Besides AGM or Lithium etc. you can also completely customize battery settings.

Always use the battery manufacturer recommended settings rather than a preset in the charger.

Unfortunately the rebulk voltage isn’t programmable in the Multi family of inverters. It is in the MPPT chargers, but not the Multis.

[smac999]

Originally Posted by tanglewood

Unfortunately the rebulk voltage isn’t programmable in the Multi family of inverters. It is in the MPPT chargers, but not the Multis.

Yes. But choosing lithuim makes it 0.2v or so vrs 1.2v or so .so I do this for some agms. Especially if they have a gen. Otherwise you start the gen at 70% and it goes to float.

What’s interesting is I have another client with older ones. Still 100 software. No lithuim option. And they charge fine.

So before they added the lithuim option the rebulk must be pretty low. Abd wheh they added the lithuim checkbox. Must have made the non lithuim rebulk much higher.

[rslifkin]

Honestly, my biggest complaint about the Multiplus is that Victron hasn't given it the better charge algorithm that their MPPTs have. That would give both adjustable re-bulk voltage and also the ability to switch from absorb to float based on amps rather than just time.

[smac999]

Amp based charging is useless because the charger doesn’t know the load.

What’s crazy is it can’t use Soc or battery current from the shunt.

[CarlF]

When AGM batteries start to behave strangely you have to consider PSOC caused capacity loss. It could be confusing the Victron (although I agree with others that the temperature compensation in this hot weather may also be causing low charge voltages)

I would test capacity by doing a capacity test. If capacity is significantly less than 660AH then do a conditioning charge. Both are described in the lifeline manual linked below.

I moved to Lithium because two sets of Lifeline AGM’s lasted less than 3 years due to PSOC.

https://lifelinebatteries.com/wp-con...al-5-06-19.pdf