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Low battery alert

Hello everybody! Here another puzzle for lead batts addicts!

In my offgrid mountain house, managed by Victron, my 30kWh/24V OPZS batts are at -4°C (outside -12°C). This morning the voltage suddenly fell from 22.4 to 20.2Volts triggering an alert. Apparenlly everything is working well: inverter, CCGX and VRM, Modemrouter with a constant load of 112W (5A) . For the last 20 days, I never reached SOC=100% but il never went under 80%

My explanation is a bad measure of the voltage, due to a bad contact, due to the low temperature. So "Wait and see".

Anyway, with so old (?) batts I am prepared to buy a new set, but that would be when the snow has thawed (May?)

Anyone with a better understanding?

Lionel SEYDOUX asked
Lionel SEYDOUX commented ·

1 Answer

Lead acid battery

Hi all. i have the orion- tr smart isolated dc/ dc charger. I’m after the settings to charge leausure lead acid batterys. Any ideas anyone.

stevendax asked
kevgermany answered ·

1 Answer

Techniques to extend battery life of Lead Acid Batteries

My batteries are almost 5 years old now. Unfortunately in the past year we had severe grid electricity outage so my batteries have been exhausted by multiple deep cycles of discharge. My system uses a 24 Sunlight 2v - RES 8 SOPzS 1380 batteries. What I am facing now is that voltage drops dramatically as batteries reach 60-65% (drops below 44v). I am wondering if there is something I can do to try to extend their battery life to try for at least 1 year or 2 years. Thanks!

samer-abi-chaker asked
scraggs answered ·

1 Answer

Victron 160AH Lead carbon batteries

Hi I've seemed to have lost a lot of capacity in my battery bank 8x 160 AH Victron lead carbon, they were new in mid 2019 so just over 3 years old, the BMV has recorded 104 charge cycles and 507 full charges ( sync to 100,%) our average discharge is 107ah, we now get a low voltage warning around 80ah, basically we have to run the generator in the evening to get something like 90% change if the solar hasn't got it above 90% or we end up with low battery warning in the morning or shutdown with voltage about 38 volts, the battery settings are hopefully in the picture below with the history page.

I've spoken to my dealer he's essentially said out of warranty and buy new lithium! I'm off grid so totally dependent on the battery bank, I've checked and cleaned all the terminals my next option is possibly removing 4 of the pack and getting them tested and charged with mains power to see if they are still usable, interested to know if this is normal for 3 year old batteries or if something is setup incorrectly?


Martin asked
kevgermany commented ·

3 Answers

Lead Acid Battery with MPPT 75/15

Hello all,

I have on MPPT 75/15 a SMF C100 lead-acid battery with the following data:

Charge current Approx. 1/10 of the C20 nominal capacity (C20: 80Ah but I have 100Ah).
Charging voltage 14,7V - 14,8V
Float voltage Max. 13,8V

The parameters for charge voltage and float voltage are clear. I am unclear what settings I should enter for equalization voltage, maximum charge current and cell equalization. Does anyone have a tip for me?

Thanks already!

ben-real asked
bill-walter commented ·

2 Answers

Lithium/Lead Acid battery bank

Hi, I have a narrowboat with 4 x 110ah lead acid batteries monitored by a BMV 702 and connected to a MPPT 100/50 Victron controller and a Multiplus 12/3000/120 Charger/Inverter.

I am looking to optimise the performance and life of the batteries and came across the combination of Lead Acid and Lithium Batteries in parallel which appear to complement their charactistics for optimum performance and Lead Acid battery life.

It appears that the recharge for the batteries is where this system falls down. Am I correct?

If this is the case, has anyone tried to separate the batteries during charging then reconnect for discharge? Would this overcome the problems in charging?

Your advice gratefully recieved


mr-frankie asked
pwfarnell answered ·

2 Answers

Charging profile for EFB lead acid?

I just bought an MPPT 100/15 as an upgrade to my system but disappointed to find there's no profile for lead acid batteries. Expected more from such a high quality controller.

I'm using a varta LFD90 EFB battery but the manufacturer does not supply any data for a charging profile.

Can I use one of the default gel profiles or will it damage the battery by staying too long in the absorbtion stage?

It's for a micro camper for occasional weekend use that will have an 80w panel on the roof which I want to use to ensure the leisure battery gets a more complete charge than the split charging system can give it.

Been all through the website and this forum and found very little information that wasn't vague or unhelpful.

I can't believe victron would sell this product without even considering that someone might want to use it with lead acid leisure batteries!

twistedvegan asked
helzy commented ·

0 Answers

Which battery technology is most suitable for use in microgrid systems ?

Hello, I hope everyone is well. From a literature search, I found that people are using lead acid batteries as an energy storage source. but from other battery researchers, they suggest using li-ion batteries for microgrid applications. so my question is what type of batteries are most used in microgrid applications?

ayoub-rahmouni asked
Alexandra answered ·

1 Answer

ESS best practices and dynamic cut-off voltage for flooded lead acid batteries

Hi all, could someone please educate me on the use of ESS with flooded lead acid batteries (and the dynamic cut-off voltage values). I am looking for best practice for ESS configuration, and specifically configuration of the dynamic cut-off voltage values, for a 24V 480Ah flooded flat plate lead acid bank of 8x 6V Leoch DT126 240Ah batteries in series/parallel (and a Multiplus ii with SmartShunt and Cerbo GX). This is for a grid parallel implementation.

From my research, I am aware of the potential issues with the MP ii going into sustain mode too soon due to the optimistic default values. And also issues with overly conservative low battery voltage alarms. I am experiencing both of these issues.

I have spent many hours researching this and haven't come up with any solid answers as yet. Please do educate me. Many thanks!

Tom Ranson asked
Tom Ranson edited ·

0 Answers

Big ole batteries

I recently acquired some big batteries.

They are 2v cells the weigh 350 lbs a pice and have a amp hour rating of 2515. They all hold the proper volts .I have yet to do a specific gravity test.

I know where they came from and have just been maintained. All signs point to the possibility of these batteries serving me well. I have 14 of these batteries and more are available but I need to find a way to charge them properly.

Do I need a charger that has an charge output amperage that is 10% of the batteries capacity?

Do I need 250 amps worth of charging to fully utilize the capacity and life?

They are Power Safe brand . G series

maintenanceman asked
xxn5ac answered ·

1 Answer

MultiGrid 24/3000/70-50 firmware v497 issue

Hi there,

With the latest firware version, I'm having an issue when uploading a different VEconfigure profile. I was able to change the profile without a system outage. With the latest firmware (and the version before it which I used for a week or so), when I change profiles the power is off for a few seconds. This creates an issue with getting everything rebooted and connected again. Is there something I can do to stop this from happening or do I just need to revert back to an older firmware.

I bit of of backend info if you care for it or you're wondering why I need to change profiles:

I'm running a 1380AH 24 V flooded lead acid battery bank. I need to equilize every 20 days ideally. To meet the battery manufactures specification or an equalisation charge I need to change the charge voltages from the regular absorption voltage. So I can it so the multigrid think its in bulk or absorp, but the voltage is set to equilise. I haven't figured out another way to do this without changing profiles every 20 days; the built in equalize feature of the multigrid doesn't work with the requirements of our system.



upperyv asked
denzel answered ·

1 Answer

Battery voltage drop when high load is connected


I have installed the following off-grid system, which has been working pretty good for one year.

  • 4 300W solar panels
  • SMARTSOLAR MPPT 150/35 48V
  • 8 Acid Lead batteries of 6V each (Deka GC15)

However I'm wondering if the behavior I see when I plug a 1200W water heater during the central hours of the day is expected.

As you can see from following graphs the battery voltage drops when load is active and jumps back to an higher value afterwards.

Reading other posts on this subject I've got this is expected indeed, but my question is: do I have to worry about this voltage drop? In other words: should I power on the AC generator if the battery voltage goes down to 46V like in the picture below?

Thanks a lot,




the-salmon asked
nickdb commented ·

3 Answers

Lithium charge cycle into lead acid battery

I have two questions relating to charging a lead acid battery with a lithium charge profile. On the vessel there will be 1x lead acid starting battery and 1x lithium house battery. The alternator will be upgraded to a Balmar unit with its own external regulator, programmed to a lithium charge profile. There will also be a Victron blue smart charger for shore power charging, I will set this charger to the lithium profile too.

This means the lithium house battery will be getting an optimized lithium charge from the alternator as well as the shore power charger, but the lead acid will also be getting this same profile. Is this okay for the lead acid battery and what is the potential disadvantages to the lead acid?

Relating to the configuration mentioned above, with the alternator charging, I assume a splitting diode for the charge is the best option rather than a charge relay?

I want to keep the system as simple as possible with the least amount of components and avoid dc-dc chargers as I want to utilize the full amps the alternator can give.

robert-van-rooyen asked
Trevor Bird edited ·

2 Answers

Walmart EverStart 27dc Solar MPPT settings

Hello to everyone,

I have searched high and low for the correct SmartSolar 75/15 Mppt settings. I have 3 Walmart EverStart Deepcycle/starting batteries that I would like to keep charged while our boat is in storage. Thanks for your help.

webeyachting asked
webeyachting commented ·

1 Answer

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