lead-acid Image


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

Batteries 92% absorption stage, battery voltage less than set absorption voltage


I have set my Quattro II with 48V lead acid (4x12V) absorption voltage setting in VE.Configure to 57,60V.

System is now:

Charger on, absorption stage.

Battery voltage 52,36V

Current 0,00A

Shouldn't the battery voltage be the same as in settings 57,60? Or is this the voltage between absorption cycles during float?

VRM/GX says that Quattro is in Absorption stage, so I would assume that those cycles (spikes in repeated absorption) happen when it reaches float stage, which it has never done yet.

My main concern is that it won't charge it to 100% level, not sure where / how it calculates the charging level. But with 0,00A current it surely wont ever get there.



Juha Tuomala 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
ben-real commented ·

2 Answers

MPPT 75/15 Parameter für SMF Batterie (Blei-Säure)

Hallo zusammen,

ich habe am MPPT 75/15 eine SMF C100 Blei-Säure-Batterie mit folgenden Daten:

Ladestrom Ca. 1/10 der C20 Nennkapazität (C20: 80Ah aber ich habe 100Ah)
Ladespannung 14,7 V – 14,8V
Erhaltungsspannung Max. 13,8V

Die Parameter für Ladespannung und Erhaltungsspannung sind klar. Mir ist unklar, welche Einstellungen ich für Ausgleichsspannung, maximalen Ladestrom und Zellenausgleich eingeben sollte. Hat mir jemand einen Tipp?

Danke schonmal!

ben-real asked
ben-real edited ·

1 Answer

Internal resistance of lead acid limiting charge wattage from solar string?

Hi there tech people,

I have a 520 watt solar string, connected in series, so 24 VDC nominal, connected to a Victron MPPT 100/50, monitored with a Victron MPPT Control and a Victron BMV700, charging two parallel 12VDC Victron 200 AH VRLA lead acid batteries (which are quite old).

I am observing a few phenomena, leading me to a few questions:


OBSERVATION 1: When the battery bank is - for example - at 96% SOC before the sun rises. Early in the morning, after the sun comes up, the BMV suddenly indicates a SOC of 100%, although the MPPT light indicates it is charging in bulk mode and there is hundreds of watts flowing into the battery. Obviously the battery is not at a SOC of 100% at this time.

QUESTION 1: Is it because the solar array is "pushing" voltage into the battery, that the BMV thinks that it is suddenly at 100% SOC shortly after the sun has begun shining on the panels in the early morning?


OBSERVATION 2: When the battery is almost full and the MPPT is in float mode and there is absolutely zero consumption from inverter (switched off) or any other consumers, I see that the system is still charging with 1-10 watts for a long time.

QUESTION 2: Does this come from the internal resistance of the lead acid battery chemistry, resulting in slower and longer charge stages when compared to a LiFePo4 battery?


Any ideas?

John Brown asked
rslifkin answered ·

1 Answer

Instalación Trifásica Multiplus 3000/48/35-16 + Fronius Symo 5.0-3

Buenas noches,

Tengo una instalación fotovoltaica trifásica con 3 Multiplus 3000/48/35-16 y un Fronius Symo con Ac-couplin. Baterías ácido plomo 750ah (Vesna Topzs 750).

Tengo red pública estable como apoyo.

He instalado recientemente el asistente ESS y no consigo la correcta configuración.

Podrían decirme la correcta configuración en el veconfigure3?

Los equipos Multiplus que tengo pueden inyectar a red? Adjunto imagen

Me están notificando batería baja continuamente, como puedo solucionarlo?


Un saludo

Miguel Roque


miguelrogo asked
miguelrogo edited ·

0 Answers

BMS 12/200

When you have a vehicle start battery that is lead acid and charged by alternator, can you use either the smart bms12/200 or BMS 12/200 to charge lithium batteries from the tow vehicle?

sbowers1 asked
steffen-graap answered ·

1 Answer

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
kevgermany commented ·

0 Answers

Orion-Tr 12/12 18Amp or 30Amp for 4x4 Offroad Lithium or Lead Acid Charging

Good Day All

I am looking at purchasing a Smart Orion-Tr 12/12, either the 18 or the 30Amp.

I currently have a 80Amp Alternator with a Lead Acid Starter Battery in my Land Rover Defender. I want to primarily charge using the DC DC charger and then I will have a separate MPPT for backup Portable Solar Charging.

I am just going to power some basic items like a small fridge and lights.

I want my Auxiliary battery to be 100Ah and I want to be able to use either a Lead Acid or Lithium in the future. I prefer the idea of the Lithium Battery but sometimes when you are in the middle of no where, it can be good to have a secondary starter battery. My concern is that the 30Amp is too much current for charging100Ah lead acid and that the 18Amp is not efficient enough for the Lithium Battery. Which unit would be the best?

Also I do not see a profile for lead acid on the VictronConnect App, how would one start to setup a profile for this?

Kind Regards


bradraut asked
kevgermany commented ·

3 Answers

Anyone found out from Victron what “advanced user settings” should be set to for Lead carbon 160s?

i find it unbelievabe that victron have not produced a more detailed version of charge rates. I have the ip67 24v blue smart charger, and could go to advanced settings, and put in what they say.....but they won’t tell, WHY.?

sud asked
kevgermany commented ·

1 Answer

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