battery charging Image

battery charging

Triple Bank setup with AGM + LiFePo4

I bought a boat and am redoing the electrics.

Reading for a long time now but I am still unsure how to connect my new setup in the best way.

I have:

- AGM for Anchor

- AGM for starter

- LiFePo4 with REC ABMS for service

- Balmar 100A Alternator

- Smart Aternator Regulator but only with AGM profiles

- Mastervolt 75A Chargemaster Plus Charger with three outputs

- Solar MPPT

Now, should I go:

1. All charging (alternator, mppt, chargemaster) to a general charge bus, then three DCDC to every Bank

2. All charging to a charge bus and then two DCDC - AGM and Lithium

3. Alternator charging to isolating Diode, from there one DCDC to the two AGM and one DCDC to the Lithium, and for shore from Chargemaster one to the DCDC to AGM and one to the DCDC to Lithium

4. Alternator and Chargemaster to anchor or starter bank, from that one one DCDC to the other AGM and one to the Lithium

5. Alternator to diode, directly to AGM and from one of them to the Lithium

Sidenote, I need to reduce the output of the alternator to about 50% to not overheat it as my regulator does not have alternator temperature input.

meerow asked
meerow answered ·

2 Answers

BYD B-Box Pro Charge Current Limit and Temp

I've been having issues with cold weather and installed mini-pad heaters onto pairs of battery (20 BYD batteries / 10 heater pads). The temperature has responded well and is now sitting around 20 degrees. Unfortunately, the Charge Current limit is still limiting things (sitting in the 2-14 degree limit range).

I've even given the BMS controller a heater pad (just in case)...

Any suggestions?


redmcc asked
Alexandra commented ·

2 Answers

Slow charging lifepo4 when freezing weather

I just learned that you can charge lifepo4 batteries in cold weather, just currents have to be low. Anyone tested this with Gerbo, is it possible to program to do it automatically? So MPPT and Multiplus II for example would charge with lower amps when freezing?

pekkaj asked
hominidae edited ·

8 Answers

SOC percentage scheduled charging

Why is it not possible to charge per 1 percent with scheduled charging? It go's in steps of 5% which causes some overvoltage issues with my BMS when it charges to 100%. 95% is a bit low, I would prefer to have the possibility to charge it to 99% if I want it to. Seems like a very simple change in the setting to apply

banne asked
Alexandra commented ·

0 Answers

Use of BMS-12-200 with 2 alternators in catamaran

BMS-12-200-question.jpgHi there,

I am interested to use the BMS-12-200 in a twin engine catamaran installation where the owner is upgrading the house battery bank to LiFePO4 batteries, and wants to keep using his regular engine alternatrors with internal regulators to charge the house bank while motoring, but without risk to his new Lithium batteries.

My question is, could we use the setup shown on the BMS-12-200 datasheet but with a two way selector switch instead of the simple On/Off battery switch shown in the diagram. Each alternator would be connected normally to its own starting battery, and we would run separate output wires to the BMS-12-200 with a selector switch to connect the charge coming from the engine running at any give time.

Many thanks for any comments or answeers.

luis-manuel-pinho asked

0 Answers

Onan 4kw and Multiplus-II

Hello, I have a 1120Ah LiFePO4 12V battery being charged by a MultiPlus-12V 3000VA 230V.

I have connected the Multiplus in-line of the feed to the 240V AC distribution panel and using the feed through facility to run the 1KW immersion and some other small domestic loads.

I also have a 4KW generator for when the "shore supply" isn't available, when the shore supply is connected the Multiplus will charge the battery fine and will also heat the hot water.

However running the generator is a different story, when I do so the Multiplus will pass through the 1KW heating load and if I turn the charging on the Multiplus will start charging, if I turn the charging up every now and again the charging stops, the Multiplus switches over to inverting and the heating load is now being picked up by the inverter and the batteries, after a minute or so the Multiplus switches back to pass through the heating load (onto the generator) and starts ramping up the charging again, it will then run sometimes for a while or sometimes more or less straight away it will trip again.

I am pulling around 3Kw which I would of thought the 4Kw generator should be able to cope with without too much of an issue.

I have set the current input limit to 16A, changed the setting in the input from "shore power" to "generator" and that may have stopped it tripping as much, but not completely.

If I cut the charger back in the DVCC it helps as does turning the immersion heater off, but the whole point of running the generator is to load it up, as this is the best for them.

HELP anyone with any ideas???

mallo asked
Mike Dorsett answered ·

1 Answer

Mobile off-grid design Challenge

Dear VE Community,

I am seeking your expert advice on a custom project that I am currently designing for a trailer application. I would appreciate your feedback on whether the design meets the requirements or if I need to make any changes.

Here are the major specifications of the system:


  • The system must be able to receive power from both one AC source (such as grid or diesel generator) and DC source (such as solar panels).
  • The system will primarily operate in off-grid mode, with "Storage" batteries used as the main power supply.


  • The system includes two "load" batteries rated at 24V and 22Ah each, which should receive a constant current between 10A and 20A to be replenished.
  • Additionally, some DC loads and AC loads needs to be fed with power. These loads are on demand and not constant baseline.

Please note that the "load" batteries are not intended to reverse energy back to the system. Instead, they will be discharged elsewhere. Think of the system as a continuous battery charger on wheels!

My current preferred design uses a Victron Multiplus II 24/3000 combined with 2x Pylontech UP2500 and a Lynx Distributor. Two DC-DC 24/24 chargers would be installed between the Lynx Distributor and the "load" batteries to charge them. According to my calculations, I should be able to replenish the "load" batteries around 4-5 times each.

I have attached a high-level schematic of the system for reference:


I would greatly appreciate your input on the feasibility of this design to fulfill its intended purpose and any potential improvements you may suggest. Any suggestions and tips before I move forward with more detailed design would be invaluable.

Thank you in advance for your assistance!

eugenioschloss asked
kevgermany commented ·

0 Answers

SOC drops slightly every 7 hours



I recently install 3 x 4kw new BYD LVLs to an existing system on grid that had 3 x 4kw BYD LVLs so a total of 6 (two towers of 3) with a Victron Quattro 48/10000/140. I since I installed the 3 extra batteries my system as been slightly dropping SOC to 99.5% every 7 hours without any change in load or mains loss. What settings can I check to see why this is happening all of a sudden? Let me know if you need further screen shots of any parameters.

Update: I have fully bypassed the inverter so there are no loads and it still dropped SOC slightly on the 7 hour mark and went into bulk charge.

Update 2: did a discharge test all worked ok, went down to 20% SOC, charged back up to 100% and it went back to every 7Hrs issue again. At a loss.

sdc88 asked
sdc88 commented ·

5 Answers

High Voltage Alerts - newbie questions - (setup details provided)

My first post. A newbie to Victron Systems. Installation is in a professional campervan conversion that is less than one year old. Built for boon-docking for several days at at time.

Renogy PV panels - 600 watts total
Pylontech LiFePo4 100aH batteries x 4
Victron Cerbo GX firmware - v2.89
Victron Orion Smart 12V/12V-30A firmware v1.13
Victron SmartSolar MPPT 100/50 firmware v1.61
Victron MultiPlus 12V 3000 120-50 120V firmware ?
DVCC screens below

AC loads are 1800W induction cooktop, 450W milk frother, chargers for laptop/tablet/portable

High Voltage Alerts (HVAs) frequent after batteries reinstalled from wither storage. Assuming that was the batteries balancing themselves? See HVAs again because of small AC drain and high solar input. (3 days off grid and batteries did not drop below 86%).

So... questions
1. Will I be always chasing HVAs because DC-DC charging + PV charging capabilities
may often outstrip AC loads?

2. Will continuing HVAs cause battery damage over the long haul?

3. Are their setting changes that will dump/divert excess charge?

4. Any other basics here that I am missing?

Any guidance greatly appreciated.



jswyukon asked
mvas edited ·

1 Answer

How to test my blue smart IP67

Batter voltage setting at 12.14v app shows absorption

greasyhands asked

0 Answers

3 phase ESS BYD high voltage Alarms

Having issues with a new system. All firmware up to date.

Has 5 RS 450/200 and a grid tied inverter on output. Batteries go into high voltage alarm and shut down the system.

Looking at battery CCL showing 0amps the Victron continues to charge also when trying to reduce charged voltage through DVCC it has no effect and doesn't follow the value set. Help needed

paul-ham asked
paul-ham answered ·

1 Answer

BUG report: SoC jumps to "SoC when Bulk finished" value, way before Bulk has finished.

ESS system: MultiPlus-II 5kW, SmartSolar 250/60, 4kWp P-V, Cerbo GX, LFP 10kWh battery (no BMS connection to the GX device at the moment). No BMV of SmartShunt, SoC calculation based on MultiPlus, enabled through VE configure.

So, the battery was drawn to 49% during the night and early morning. Sunny day since, and the solar is ramping up. SoC and battery voltage gradually rising as expected. Bulk voltage is set at 55.2V and float voltage at 53.6V.

At the exact moment SoC reaches 73%, while the battery voltage is still below the bulk target voltage (it reached a maximum of 54.81V according to the controller), SoC percentage jumps to 95%, which is the "percent when bulk finished" value. However, the system is still on Bulk charge, and will be for a couple of hours more. Actual battery percentage is at 74%. SoC will remain at 95% until bulk charge is indeed complete and then SoC will slowly ramp to 100% during Absorption.

This has been kind of happening since the beginning. Any ideas why? Any insights? Here's the link to this installation, in case someone wants to have a look:

Looks like the jump happens as soon as battery charging current reaches the maximum value I've set on DVCC, which is 45A, and I did that to keep the controller working a little bit less. DVCC was enabled on this system with no BMS-connected battery, purposely to be able to ramp down charging current, so as to lift the burden off the controller a bit.

Chiming @mvader (Victron Energy)

Wouldn't it make much more sense if the SoC calculation followed the same rules as the SmartShunt?



thanar asked
thanar edited ·

4 Answers

VE.Bus BMS and standard 15amp 115 volt receptacle

Greetings from Southern California !!

A hair-brained idea:

Has anyone considered - or perhaps even designed the circuit - to use the high/low signals from the VE.Bus BMS to trigger a relay to energize / de-energize a standard 115 volt receptacle??

I’m thinking of such a device to control a non-victron battery charger / converter. Mostly just to de-energize the device if the BMS is unhappy with an individual cell.

Thanks !!


stevew asked
mvas answered ·

1 Answer

DC to DC Converter set up on twin outboards

I twin F225 Yamaha outboards, with lead starter batteries and 200ah house SOK lithium. My set up is Victron multiplus II compact 2000, with 712 smart shunt, and 12-12-18 amp DC2DC charger. The DC charger is on an A/B switch for the port and starboard engines. I did this to balance engine hour use. I would like to add a second dc2dc converter, one for each engine and starter battery.

Engine Alternator produce 45 amps but uses 18 for the engine and puts out 27 to battery.

Can you advise what issues I should look for and is it possible to run 2 DC/DC chargers from each engine starter battery and what would the wiring look like?

ww2bar asked

0 Answers

Solar power being wasted.

We are generating 11kw on solar, using 4.4kw but only charging at 900w. The charge rate varies but we seem to be loosing a lot of generated energy. We have 4x BYD batteries, Victron CerboGX, 4x Fronius Primo solar inverters and 2x Victron Quattro 48/10000/140.

Our connection to the grid is disconnected; if we connect to the grid then we export most of the power rather than charge the batteries.

bill-wilson asked
matt1309 answered ·

1 Answer

2200 Posts
1209 Users

Topic Experts

1951 Points
1272 Points
1241 Points