AGM Battery Image

AGM Battery

Orion DC-DC, AGM, Lithium & Wakespeed

Hi all,

I am trying to understand the best way to charge both Lithium (House) and Led Acid (Start) incorporating a WakeSpeed regulator.

There are various diagrams online but it’s not totally clear how the combined setup works.

Would one of the two set ups below work? Or does anyone have a simple diagram to visualise the correct approach? Thanks.


colm asked
colm edited ·

2 Answers

DC2DC charging discrepancy


I have batteries that are charged through solar and DC2DC. Recently the DC2DC has been going into absorption before the solar and reading the battery voltage as around 0.1v higher than the smart shunt and the MPPT. Both chargers are set to AGM spiral per seller guidelines, I can't seem to find direct manufacturer technical specs.

Is there anything that could be causing this discrepancy, I have checked the wiring and it's all firmly in place. The breaker was recently switched off by a falling box while driving but still flips on and off as usual. All pieces of kit are fully updated.

Many thanks,


laurapakora91 asked
Alexandra commented ·

0 Answers

Phoenix Smart IP43 voltage too high for my AGM?


I have my Phoenix Smart IP43 charger setup to load my Varta Professional AGM 95ah battery.

I set the setting to AGM spiral cell, the values match w/my battery. A shame that there is no general AGM setting :(

I also have a smart sense temperature sensor linked in the smart network.

What I noticed though was that the charger at some point had 14.9-15.0 V. That is too high for the battery? I wonder because the setting AGM Spiral says 14.8 max.

Any ideas?

neothehacker asked
Stefanie (Victron Energy Staff) commented ·

1 Answer

brand new Victron AGM battery capacity

Hi everyone,

I've just bought a Victron AGM 220 Ah 12V battery.

As it will be inserted in a 48V battery pack, I've measured the C20 capacity as well as for the three other existing batteries.

Before to check the C20 capacity, the battery was charged with a Victron charger.

4.7 Ah was added to fully charge the battery.

Then a 11A constant current was drawn from the battery during 17:42 hours, wich gives us a 195 Ah C20 capacity.

Ambiant temperature was found between 15 and 17 °C.

Then battery was fully charged again with 22 A bulk current :

so 183.8 Ah in Bulk, 55,1 Ah in absorption, so a total of 238.9 Ah loaded in the battery.

charge efficiency is 81.6 %.

Is it normal that C20 was found 11.3% lower than specified for a brand new battery and morover lower than 2 years old batteries?

Does this capacity increase after a few discharge/charge cycles ?

What are the manufacturer tolerances values about C20 ?

Thanks for your Help.

N.B.: the three other 2 years old batteries C20 capacity was measured with the same method:

B1 : 212 Ah

B3 : 211 Ah

B4 : 207 Ah


cargol66 asked
melbournepark commented ·

2 Answers


Bonjour, les batteries Victron AGM supportent-elles l'égalisation ? Si oui, à quelle tension et pendant combien de temps ? Merci

beaudru asked
kevgermany commented ·

0 Answers

courant de charge minimal

Bonjour, charger une batterie AGM à 2% de sa capacité (2A pour une 100Ah) va-t-il réduire sa capacité ?

beaudru asked
kevgermany commented ·

0 Answers

How do I wire 12 agm batteries to a 24v inverter?

I have 12 used agm batteries that I want to configure to a single 24v batterybank. How would you wire this in the best way? Do I need balancers? If yes, how many?

mattie asked
nesswill commented ·

3 Answers

Charger IP67 12/25's going nuts: voltage fluctuates in Bulk, Abs, Float, Storage


any help is appreciated. IP67 12/25 is connected to AGM battery with 92 Ah, temperature -2° C.

In all charging states the volate is fluctuating. Charge algorithm "AGM spiral cell" has been chosen (abs 14,70V, float 13,80V, storage 13,20V.)

On the left you can see the charger working in storage-mode. DC-load was 3W for Globallink 520 and some USB-sockets without any load. Look at the curve: Voltage is fluctuating every second (not seen here because Globallink gathers data only four times an hour.) But when i am checking the Voltage via Bluetooth right beside the installation i can see that voltage fluctates between min 13,30V and max 13,70V! That i am not reaching 13,20V is ok due the temperature of the battery while using temperature compensation as it is set by factory (-16,70V/°C) Is that normal behaviour?

On the right side of the chart you can see the same battery being charged without any load by a CTEK MX 5.0 Polar. This charger also compensates the batteries low temperature but look at the voltage of the charging states: bulk, abs and float are clearly visible and NO VOLTAGE HOPPING.


thshh asked
thshh commented ·

1 Answer

AGM Super Cycle Charge Voltages
I have just bought a 125Ah AGM Supercycle Battery. I’m not sure why the data sheet and the information on the side of the battery don’t look the same.Could someone please advise me on the best Absorption, Float and Storage voltages for this battery. I have a Blue Smart IP65 charger and a an MPPT Blue Solar charge controller.



Float Service

Cycle service Normal

Cycle service Fast recharge


14,2 - 14,6 V

14,6 - 14,9 V


13,5 - 13,8 V

13,5 - 13,8 V

13,5 - 13,8 V


13,2 - 13,5 V

13,2 - 13,5 V

13,2 - 13,5 V

hartleb asked
Stefanie (Victron Energy Staff) answered ·

1 Answer

Airstream AGM lifeline battery with BMV-712 Smart


First post and question about BMV-712 Smart. I have a 2019 Airstream with AGM batteries, 1000W factory inverter/charger and factory solar (180 watts). My question is the battery profile, I can't seem to find any information as to what to set the battery parameters to. It seems flooded and lithium are covered but not AGM. Does anyone have a reference of those settings should be? The batteries are 12v in parallel. The system works fine, I just want to ensure I have the correct floor values, charge voltage....etc... thanks for any help in advance. The batteries used are here:

kittmaster asked
eseidman answered ·

1 Answer

Décharge batteries Victron AGM 110AH


Lors de ma visite hivernale à bord, j'ai eu la désagréable surprise de retrouver mes 2 batteries servitude Vitron AGM 110 Ah vides. J'avais déjà eu le coup en mars dernier lors de la remise en fonctionnement et après une bonne recharge, elles ont fait la saison sans sourciller. Pour cette fois-ci, je les ai ramené à la maison, chargées à bloc et je surveille maintenant leur tension. Ma question : qu'est-ce qui peut bien provoquer leur décharge en 2 mois, sachant que tous les consommateurs sont coupés, coupe-circuit actionnés, il ne reste que le BMV 712 Victron en fonction à priori. Court-circuit dans une batterie ? Coupe-circuit collé et fuite électrique ? J'ai aussi le MPPT Victron du panneau solaire branché dans le système.

Je suis preneur de vos expériences en la matière. Merci à tous

spi asked
touteslesbatteries answered ·

3 Answers

EasySolar-II 24/3000/70-32 - Battery Capacity setup


I've installed a EasySolar-II 24/3000/70-32 with two AMG 260Ah 20HR 12V batteries.

The system is running, but I didn't find the setup for the battery capacity.

Can someone please tell me where to find the setting for the capacity and also for the SOC?

Thank you very much.

Philipp Sessler asked
Paul B edited ·

1 Answer

What size wire and fuse. Please

I have 5 12v 240ah AGM batteries. Which I need to wire in parallel question what size wire between batteries and what size fuse, question 2 what size wire from batteries to inverter. Inverter is a multi plus 2 12v 3000va 230v . The distance from the batteries to inverter is 2.5m

ggreen asked
Alexandra answered ·

3 Answers

Victron Super Cycle AGM sizzle and smoke

Hello Community,

Our domestic battery bank almost blew up on a 17 hour motor sail.
We are really happy that the Victron battery chassis are very very strong.

This is the setup, domestic battery, solar, and MPPT installed in Q3 2020:

  • 2x170Ah Victron AGM Super Cycle domestic bank
  • Victron 100/50 MPPT Charge Controller
  • Victron BMV 712 Battery Monitor
  • Victron 12/2000 230V Inverter Q3 2021
  • 400W LG Bifacial Solar
  • Volvo Penta MD2030 diesel with alternator
  • Bosch 90Ah starter battery 2019
  • Victron Argofet Battery Isolator
  • 70mm2 marine grade wire on batteries to bus bars and to inverter

Turn of events (It may be TMI but I will give location too, to make sense of distances and daytimes):

  • We left the boat on a mooring ball for 3 months in Grenada, the MPPT has been topping up very consistently just enough to keep the batteries full
  • We came back and used the boat on anchor and did short 1-3 hour sails under engine around the bays, all was well, batteries nice and full
  • Then we did a big jump under engine that blew up the batteries:
    • Monday morning we leave Tobago Cays to Bequia, a 5 hour motor trip
    • Monday noon we stay on anchor in Bequia, it is sunny
    • Monday evening we start our next leg after sunset, through the night we motor and get 10 hours of alternator power
    • Tuesday all day, we keep motoring and arrive in Martinique in the afternoon around 2:30 PM
  • After dropping anchor and stopping the engine we hear sizzling noise and smoke from the battery compartment. The batteries are smoking hot and bulging. We switch off ALL power and disconnect the batteries, take them out into the dinghy where they leak and melt the dinghy non-skid due to heat. We dispose them later that day at the marina.
  • We noticed no high voltage. After disconnecting, the batteries were at 13.5V
  • The starter battery is at 12.9V and has no damage
  • The MPPT is set to the Victron AGM deep cycle preset
  • The MPPT has bulked 100% and put 1.7kWh into the bank during Tuesday!

I am suspecting the following:

  • The alternator kept all batteries topped up, starter and domestic, but somehow the MPPT kept pushing all day as well, into domestic only. This is my only explanation to as why the starter is fine but the domestic overcharged.

Why we didn’t notice before a long full day motor trip:

  • On anchor there is no alternator and we use solar only to top up batteries. It is a well balanced system and we get and use between 1.5kWh and 2kWh per day
  • The alternator provides around 25 to 30 Amps when it detects a medium full battery, it dials down to 5 to 0 Amps when full, it is working as expected
  • The only time where both systems were in full use was on this full day long motor trip. I believe there is something wrong in the detection of needed current from the MPPT, misinterpreting as to what the battery voltage really is, when the boat is being used in conjunction with the alternator charge current.

Now, we installed Mastervolt 2x160Ah AGM, the only available option for us on Martinique. I am monitoring charge cycles on anchor as well, screenshots provided. You can see time of day at the top.

mastervolt charging screenshots after fresh

I attach all data I could gather in this post. “Yesterday” in the MPPT screenshots is the day of passage. “Today” is on the new Mastervolts. Even on the days before the incident, the MPPT should not have charged that much in my opinion, as we motored as well. I am confused this happened because the MPPT setting was set on the exact battery preset and the batteries are 2 years old, being actively used for about 1 year. We rarely go below 12.3. I am very happy that the Victron battery chassis held up strong and didn’t catch fire. But there's quite another mix of emotions when I think about how this could happen with an all-Victron charging and storage setup.


On our next daytime motor passages we will monitor the MPPT charging patterns closely and when in doubt switch off the MPPT to prevent overcharging.

SmartSolar_ChargerMPPT_100_50 Victron

SmartSolar_ChargerMPPT_100_50 new Settings mastervolt





Your thoughts on my hypothesis? And more importantly, how can I prevent this in the future?

alexander-arnold asked
angusbeau answered ·

4 Answers

MPPT 100/30, Battery Sense and BMV702

I have two AGM battery banks with existing BMV702 monitors (no temp sense installed). The banks are in the engine room of my boat.

I am installing an MPPT 100/30 on each bank and am a little concerned with voltage and temp compensation. The controllers will not likely be in the engine room, and will be about 10' away from the batteries.
Am I best to install a battery sense on each bank, or am I able to get the bluetooth dongle and temp cable for the BMV702's and use that somehow ?

or, am I overthinking things. The batteries never get over 35 C, that is only 0.12v of compensation needed which should not be a problem if I set the voltage parameters in the middle of the band for my batteries.

rob-mills asked
JohnC answered ·

1 Answer

197 Posts
176 Users

Topic Experts

235 Points
171 Points
100 Points