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AGM Battery

Upgrading my power management system to Victron and have questions

Hi All,

I have been running a 125 aH AGM in my camping rig (for coach battery) for five years and it finally gave up the ghost. This setup was only good for about 36 hours…so I ordered a matching pair of the same battery for a total of 250 aH.

Since I need to build storage for the additional battery, it’s time to upgrade my charging system. I’ve been doing a ton of research on Victron products and think I’m getting close.


  • Two VMAX SLR125 125 aH AGM batteries in parallel for a 12v system (both new)
  • Usually use less then 4 amps when boondocking (for a bedroom fan at night and fridge at all times)
  • Will be adding some LED lights for night use
  • Jeep has 160 amp alternator
  • Previously used a National Luna battery box and NOCO Gen2 (10 amp per bank) for shore power and charged straight off the alternator

Battery Specs:

  • Specifications:

    Nominal Voltage 12V

    20Hr Capacity 125Ah

    RC (min) 260

    Energy (kWH) 1.7

    Terminal Posts 8mm

    Dimensions 12.9"w x 6.8"d x 8.5"h/8.7th**

    Weight 75lb

    Charging Current* 8A-35A

    Charging Voltage 14.4V-14.9V

    Float Voltage 13.5V-13.8V

Plan to order:

  • Victron Blue Smart IP22 12/30 for shore power
  • Orion Tr Smart DC-DC 12/12-30 for charging on alternator
  • Victron shunt (TBD)
  • BMV-712 monitor (TBD)
  • Probably a Victron near-battery temp & voltage sensor (temp drops below freezing here in winter)

As you can see, this is a simple system and I’m only trying to add power for additional camp days. Solar charing is off the menu until I purchase a new roof top tent that will accommodate solar panels. For now, alternator and shore power will be the only charging methods.

I’m hoping that knowledgable people here can check my work and suggest any changes if I’m on the wrong track. There are no Victron dealers or installers in my area, and I worked in the car stereo field when young. I can handle the wiring, but it’s bee a while since I’ve tackled something so intricate.

Also, I’d like to make sure that all Victron components will handle a 200 aH LifePo4 bank in the future when these AGMs die again.

Am I correct in choosing a 30a charger for home and a 30a DC-DC for alternator charging?

Many thanks for any help!

jeepcamper asked
jeepcamper answered ·

3 Answers

Telecom batteries mounting limitation


I wanted to confirm if telecom batteries can be placed horizontally with terminals facing front. As we have a not high enough space in the power room. Thanks.

dgmar-ni asked

0 Answers

maximum wattage load with quatro 3000

I have a quatro 3000 24v and doesn't like to run to 2000 watts for very long, I know its supposed to handle 2400 continuously, so if its not the quatro what else might be not coping with the load?

philv asked
philv answered ·

3 Answers

Specifications For Outback System Victron Energy 12V/110Ah Deep Cycle Batteries in Series 48V system

Have asked reseller about battery specs. Info varies quite a bit. Outback says need better specs, hopefully someone here can help. 48V system in series.

Need Absorption Voltage & A time. (what I have been told 14.6 x 4)

Rebulk Voltage. (no info so far)

Float Voltage & F time. (13.8 x 4)

EQ Voltage & EQ time. (Told not recommended)

Current limit. (told 11Amp on 110 Ah battery x 4)

Any help to clarify so I don't trash the new batteries would be appreciated.

sgaugian asked
kevgermany commented ·

1 Answer

Hybrid Lithium AGM setup

I am planning a battery upgrade for my new 4x4 which comes factory with a single 105ah AGM battery.

Due to space constraints I am planning to add around 100ah of LIFEPO4 prismatic cells to beef up the capacity.

All the loads i want to run are already wired off the AGM battery and I don't want to move all the circuits over to the lithium battery. The vehicle has a very complicated electrical system that I would like to leave as standard as possible.

So the plan is to have the lithium charging through a DC/DC while the engine is running, then when the engine is off the DC/DC will disconnect and the lithium will be used to charge the AGM as my camping loads slowly deplete it. In theory the AGM will stay at 100% SOC until the lithium is discharged. Then the lithium cuts out and I am discharging from the AGM.


I think this will work but welcome any comments, I'm a little out of my depth here.

The current plan is to use another, smaller DC/DC charger from the lithium into the AGM. Although looking at the voltage curves I wonder if I could save some money by switching to a cheaper DC/DC converter set at 12.8v, or even just a Victron Smart Battery Protect. With the battery protect only, the AGM should see a float charge of 13.8v from the full lithium, dropping down to 12.8v as it discharges. Then, I guess, they both both discharge together until the BMS cuts the lithium out at 12.0v. By which time the AGM is empty anyway and I need to run the engine or stop drawing power.

Is this reasonable? Or should I stick with a second DC/DC charger?

werdna asked
werdna answered ·

4 Answers

Is this battery safe to use ?


I have 4 AGM 12-125ah batteries & one of them appears to have been dropped in transit at somepoint on one of it,s edges, which has lead to 2 small cracks in the base & very minor 'lump' on the side of the edge. There has been no leaking or forming or crystals at all anywhere around the damage. Battery still reads 12.8 (completely unused)

My question is, can I still use this battery? If so, will it need to be repaired of maintained in any way?

First two pictures are of the cracks (on the bottom), 3rd picture is side view of the edge which is appears to have fallen on


newspark asked
Stefanie answered ·

1 Answer

Smartshunt Lug Size

I am contemplating installing a Smartshunt 500A to monitor my house battery (and possibly running battery on the alternate channel). I've looked through the manual and it specifies that the 2 bolt terminals on the unit are M10 in size. This would correlate to a 3/8" lug. So why on earth would Victron make the studs this size? It is standard practice that positive terminals are sized at 3/8" and negative terminals are sized at 5/16". At least that is the case in the US. In wiring this I would start at a 5/16" (aka M8) terminal at the battery, step up to 3/8" (aka M10) on both Smartshunt terminals, then back down to 5/16" at the bus bar. This would require custom cables of course. Is this really the way that Victron designed this unit, or am I misinterpreting something?

grayjp5 asked
trevor-bird commented ·

6 Answers

Novice need battery shunt advice
Hello :)

Total novice looking for advice on battery shunt settings.

We have a Smart Shunt (500a), 95ah 12v 1140wh AGM class A leisure battery fed by a 130w solar panel and MPPT 75/15 controller.

I’ve read the smart shunt manual and gone with what I thinks best. Waited for a float charge status with no draw and synchronised to 100%, consumed about 14ah (evening / overnight) but woke up this morning with the battery at 100% even though the controller is still in bulk charge so don’t think this is right?

Any advice greatly appreciated.

Screenshots of battery shunt and solar controller settings in app



mjs88 asked
JohnC answered ·

2 Answers

Recently charged car battery won't start

Hey All,

Recently purchased a Victron 12v 15A battery charger.

Charged my century battery of 2 years as the car was not used in over 2 months and it charged completely (used recondition option) over 24 hours. Charged 66 AH?

It has been less than a week and the car won't crank, have only started it here and there as I don't currently drive.

Is it possible that the battery is just dead? or could there be something else draining the battery when not in use?

I thought when the battery passes the device test and holds a charge it would work normally or at least hold a car for longer than a few days.

Was able to jumpstart the Car using a Gooloo GP4000.

Car is a Mazda 6 2009.

Would appreciate any comments.


jarjarbinks asked
kevgermany commented ·

1 Answer

Configure Victron Connect for smart shunt 12v 125 ah AGM Batteries

Hi all, first time poster here. I’ve been searching the internet for this answer. I am struggling to configure my new Victron SmartShunt. I am in no way experienced in this area, I have high school physics and google at my disposal.

Using the VictronConnect app and Victron energy settings guides online, I have set several of these settings, but I need help with a everything after discharge floor (screen shot included).

My problem is that the smart solar in the victronconnect app is showing the charge status as float, and from what I understand this is due to the batteries being full and only small amounts of charge are entering into the batteries. The smart shunt however is just continuing to decrease as power is utilised and it does not appear to be taking the solar into consideration and thus increasing it’s percentage charge. I think this may be because the settings haven’t been calibrated correctly and are still on the default settings since the shunt was installed (not by me, an experienced installer), however if I am wrong and you think there is a wider problem please inform me.

My set up includes:

2x 12v 125ah AGM deep cycle batteries and of course the smart shunt.

The solar panels are 2x 150w panels, and a smart solar charge controller.

If anyone has similar issues and or batteries and could help me with the rest of the settings, I would be very grateful.


Jessica Davies asked
Mike Dorsett answered ·

1 Answer

Harvesting unused daytime solar

During the day, our solar is producing an EXCESS generation of up to 20kW per day (around 30 -40kW per day). Our grid meter is not so smart, so we feed it back into the grid for free at the moment. Our total power usage on average per day is about 26kW of which we use (get charged for ) on average 12Kw overnight when there is no solar production, so, basically, a low constant usage powering fridges, freezer, lights, TV, kid's devices etc. If we use the ducted AC, I see that it consumes between 4.5 and 7.4kW per hour extra when it is powered on.

There is one household circuit that supplies all of the above appliances except the A/C.

I have access to about 30kW of new AGM batteries configured @ 48V.

So, what would the best way be to..

1. Take that circuit off-line and attach to a Victron Multiplus 2 or Quattro

2. Attach the Victron to the excess electricity that the solar produced during the day, charging the battery bank.

3. Use the battery bank for night time power for the above appliances, thus eliminating my 12kW night time consumption.

Thanks in advance

petere101 asked
petere101 answered ·

4 Answers

Lifepo4 and AGM with Bluesmart 30/12


I have two Victron Super Cycle AGM 100Ah batteries in my boat and to Charge them I use Victron Bluesmart IP22 Charger. Can I replace one of the batteries with LiFePo4 battery and use the Lithium setting in the charger? Will it ruin the AGM battery? I have the setup as stationary in my boat so that I only have to plug in the powe cord when I arrive home.

Juhani Tuominen asked
Juhani Tuominen answered ·

2 Answers

Quality of leroy Marlin Xunzel agm battery?

Last week I bought an agm solar battery from leroy Marlin.

Name solarix, brand Xunzel.

Is leroy Marlin brand for all solar accessories.

I will use it to support my agm victronenergy, either separately or in parallel as needed.

It has charging and internal resistance characteristics very similar to the victronenergy and this is good for parallel.

In fact, measuring with a schunt the current was divided almost perfectly (in relation to the capacity).

What do you think of these batteries and this brand?

They are medium quality batteries ... Not at the level of agm rolls or troyan, but not bad either.

The price range is about that of victronenergy agm batteries.

The data sheet is very interesting:

It performs worse in cold weather than victronenergy.

It has performances similar to victronenergy in terms of capacity in relation to the C rate, but victronenergy is slightly higher.

But it has performances of duration in cycles and in years much superior to the agm victronenergy.

100% DOD: unknown victronenergy, xunzel 400 cycles.

80% DOD: victronenergy 400 cycles, xunzel 600 cycles.

50% DOD: victronenergy 600 cycles, xunzel 900 cycles

30% DOD: victronenergy 1500 cycles, xunzel 1300 cycles.

10% DOD: unknown victronenergy, xunzel over 2000 cycles.

Standby use at 20 C°: victronenergy 7/10 years, xunzel 10/14 years.

Basically it appears that these xunzel agm have high DOD performance, similar to victron agm supercycle.

Victronenergy deep cycle AGM years or cycle duration is not exceptional for a solar battery at these price.

Here the two datasheets: AOvVaw0AWZwMcTcRp-3RcREF_PXQ

FRA asked
klim8skeptic commented ·

3 Answers

MIx AGM and LiFeP04

Serious question, please bear with me.

It seems that some boaters are supplementing tired AGM batteries with extra LiFePO4 batteries in parallel. My understanding is that this shouldn't be done. But I hear that many are pleased with the results.


Are there any gains?

Are there drawbacks?

Are they fooling themselves?

Are there any dangers involved?

kevgermany asked
houser answered ·

4 Answers

SmartSolar 100/30 - Batterieeinstellungen-





Hallo liebe community, ich möchte gerne die optimalen Batterieeinstellungen im smartsolar einstellen, werde aber nicht ganz schlau aus dem datenblatt vom Batterie hersteller -reichen die Daten aus ? Danke schon mal voraus

knausios asked

0 Answers


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