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Correct circuit breaker amperage for Orion DC to DC 24v 17Amp

I am trying to figure out what is the correct circuit breaker size to use for the installation of my Orion DC - DC 24/24 -17. I am using 10mm2 cable from the Orion to input (van batteries), 6mm2 from Lynx distributor to Orion.

Calculations using the formula: Current (Amps) = Power (Watts) / Voltage (Volt) suggests a minimum 25 amp circuit breaker, therefore I consider a 30amp.

However, I have read in another post, that I may use a 40amp Mega fuse in my lynx distributor (as that is the smallest mega fuse available), does this also mean I should use a 40 amp circuit breaker as well?

Any help, much appreciated

newspark asked
newspark commented ·

1 Answer

BMV-702 showing twice the throughput of power/amps coming in/going out

Dear community,

it's been a while since my last post. Hope anyone can help me.
I've recently started a new project converting a RV compartment installation with no-name components + AGM to Victron components + Lifepo4 battery.

The setup:

- 1x Standard Starter Battery (built-in by default) only in scope for the Booster

- 1x Lifepo4 100ah

- Victron Smart Charger 12/30, Victron DCDC Booster 12/30 non-isolated, Victron MPPT 100/30, BMV 702, Victron Inverter Compact 12/2000

- Positive/Negative busbars centralizing connections from/to lifepo4 battery (only)

All the component's negative poles are connected to the negative busbar, which is connected to the BMV 702 Shunt. The output pole of the Shunt is exclusively connected to the lifepo4 battery.

The only negative which does not go through the Shunt is the negative, which is connected to the grounding star of the vehicle/starter battery. This shared negative is used for the Booster.

Now I'm experiencing a strange behavior regarding the correct measurement of the shunt. If I plug in the Smart Charger, which can push up to 30A to the batteries, I see almost the twice the amount of amps on the BMV. Same goes with consumers like the Inverter, expected to be pulling around 200A for running a coffee machine, then I see around 400A. This applies to any consumer of the compartment.

Currently I see two possible causes:

- BMV 702 is faulty (but must be a strange fault) - I rule out an calibration issue. It measuring 0 amps if the main switch is turned off

- Some strange grounding effects. The starter battery and the lifepo4 battery share the grounding mass.

Do you have any idea/experience what could cause this behavior?

Looking forward to your answer. Thank you.

crownroyal asked
crownroyal answered ·

1 Answer

Clarity on amp usage when comparing 12 V bulb via MPPT v's 240 V bulb via inverter

Sorry if this question is somewhat amateur, but I'm rather new to this ....

In the following scenario I have:
- one 5 W / 240 V LED bulb connected to a 240 V inverter (5 / 240 = 0.021 A)
- one 5 W / 12 V LED bulb connected directly to the MPPT (5 / 12 = 0.42 A)

Do you agree my calculations are correct; does this effectively mean the 12 V solution places a greater load on the battery and will consequently deplete the battery more quickly than its 240 V counterpart?

Best regards

bazil asked
Michelle Konzack commented ·

2 Answers

cable size mppt to battery


I have a 75/15 Victron mppt, can you give me guidance on what cable that I should use to connect it from the Mppt to the battery. I have been advised on a forum that 10amps is okay but looking at the data sheet I may need more. Any help is appreciated.


dmin asked
dmin answered ·

3 Answers

Orion DC-DC overheating

My Orion Tr Smart 12/12-30 Charger runs hot, and the output current folds back considerably. Anyone else with this problem? When cold, it will output 33A. When hot, it will fold back to 26A or less. Parts of the case may exceed 134dg F, in a cool (60dg F) environment. By adding a 80CFM fan above the fins, the case temperature is lowered by 20 degrees F, and the unit will continuosly output 30A. It would appear that the heat sink is undersized. Comments?

mdbrown asked
petaramesh commented ·

7 Answers

Chargings AMPS to battery and to my loads

I have an Offgrid system with a Victron Multiplus II 5kva and with a 250/100 Mppt charge controller and a 150/70 charge controller conected with plumb - Acid batteries which have a charge limit of 50 amps. The solar panels have more power so we thougt to charge either the batteries with 50 amps and cover the loads with the rest.

Also if how i can avoid that the generador charges the batteries with the max allowed of the 50 amps and also the mppt charge controllers with another 50 amps?

Which settings should i use either for the Multiplus and the Mppt´s to get cover this funcionality we need?

Thanks a lot

bjorn-padotzke asked
kevgermany commented ·

1 Answer

No amps out of my ip67 charger

Hi I have had this charger for 6 months, has always worked great.

I am trying to charge a lithium battery.

It is showing 14.20 volts and 0.0 amps

I have tried on another battery and another power source.

No output at all.

And ideas please


bradley-durkin asked
kevgermany answered ·

1 Answer

Lynx Power In really 1000A ?

The Lynx Power In, like the Distributor, are advertised with an intensity of 1000A. Without going into the technical details of scientific calculation, we take an average of 1.2A per mm2 (maximum of 3A per mm2 according to the calculation bases of one of the 3 world leaders in professional electrical boxes and safety for busbars). However, the two Lynx have a bar of 30 * 8 mm. This gives 240 mm2. We multiply by the technical average of 1.2 and the result is 288A, or by the maximum of 3, the result is 720A, but never the 1000A. Do you have more information to send me on this subject? Thanks in advance.

myhomebuzz asked
johnsmith edited ·

5 Answers

IP65 12/10 no amps while charging in bulk/absorption

Hi guys @Matthias Lange - DE

More or less new to this device, it works really well the last 9 charges on my aldi deep cycle 80Ah lead battery, however this time i'm getting no amps when trying to charge it. it stays a short period in bulk and goes to absorption before float quickly. (see history) A mutlimeter on the battery gives me no volts at all at 0.06V, I assume the battery is a beyond a charge?

I'm not certain if it's the charger that is not working.. even not connected to a battery it is in absorption mode with 14.4V and no amps. when I reset it to defaults, it goes back to to that phase. is that normal?

many thanks


alzoo asked
kevgermany answered ·

3 Answers

BM 712 Not Displaying Amps for All Loads


I had an old diesel heater wired directly to the house batteries. I could monitor heater amp draw on my 712 quite easily. I replaced the diesel heater, and added a Blue Seas fuse block, to which I connected the heater. The negative (ground) for the heater still was connected to the house battery.

When I run the new heater, I am not able to see amp draw on my battery monitor. All other devices (lights, pumps etc.) display the amp draw.

The first thing I will do is connect the heater back to the battery directly and not use the fuse block (I will try this tomorrow). Does anybody have any other ideas on how to troubleshoot?



apw asked
apw edited ·

2 Answers

800 watts of solar full sun. Victron 150/100 charger controler volts/amps fluctuate


I'm still trying to figure out if anymore mistakes have been made in a Professional install? The last couple days in Quartzite AZ it's been full sun. I noticed in monitoring the Victron app when the voltage goes up the amps from the panels goes down? And it looks like a EKG every second or 2 I see one go up and the other down this continues until the sun is gone. I'm also concerned they didn't wire something correctly because before the solar I had a factory installed 1000 Watt inverter that kept the residential refrigerator going off 2 75 AH lead batteries. These 2 batteries could power the fridge and Starlink for 8+ hour's before the inverter shut down. After having the system for almost a week I haven't been able to get the 2 Battle Born Game changers past 70% on solar only and have had to run a generator for 2-3 hours to get them to 100% before we would retire for the night. I'm seeing 500+ Watts from the 800 watts of panels parallel/serial but should the voltage and Amps be swapping like This? Could this be why I'm not getting a full charge off the solar? I haven't been on the roof yet to check the connections. I found a few oversights already on the ground like the tension reliefs inside the Multi plus II were not tightened at all leaving the 120v wires are risk of coming loose from vibration during towing of the camper. What should I look for that could be causing this? I'm not going back to the place it was installed at the guy who worked on this part of it cops and additude when I find mistakes I bring to there attention. They even tried to keep parts I needed like the termination jacks. So I'm just going to have to check everything myself and fix it. You can see how much power I've generated over the past few days. The only thing running is the fridge, a TV , small Roku on the TVs USB power and a Starlink. The Starlink maxes out at 80-90 watts, the fridge 200w when running and the TV about 60 watts. Maybe I just need a few more panels? Sorry it's so long I don't know how else to explain what's happening after dropping $15k I should have done it myself.

saboken asked
klim8skeptic commented ·

0 Answers

Should Victron Blue Smart IP22 amps be fluctuating strangely during float?


I recently upgraded my RV to LifePo batteries (two 100AH). While doing so I upgraded the converter/charger to WFCO’s auto sensing unit. I also installed a Victron Smart Shunt. I fairly quickly discovered a now known issue where the WFCO unit does not do a good job of actually detecting lithium properly and never goes into a proper bulk mode. This means that I would never see more than about 10-11 amps while charging. Once the batteries would eventually reach full charge it would float and maintain 13.6 volts and a fairly consistent small positive amperage to the battery according to the Smart Shunt (this is from my memory).

Because of the low charging amperage issue, I decided to remove the WFCO converter/charger and purchased two Victron IP22 30Amp Smart chargers. I was able to place them within 5 feet of the batteries where the WFCO unit had been over 20 feet away. I hooked them all up and was thrilled that they delivered 55+ amps during bulk mode.

Unfortunately, I have discovered something that strikes me as odd once they go into float mode. The voltage stays fairly consistent with only very small fluctuations like 13.49 to 13.51 volts using the lithium setting. However, the amps bounce around like crazy. They fluctuate from around -1 to +2 constantly. As in, they will bounce around in that range a couple of times every second. I have attached a screen shot showing this behavior in the trends area of the app. I have a small load present at nearly all times for my RV.

Is this normal? I am 99.9% sure I did not see this behavior when I was using the WFCO unit. Are the IP22’s not well suited for the task I am asking them to do?

Things I have tried with no change. I have removed all items from the VE network, unplugged each of the two IP22’s one at a time to see if one of them was behaving badly, changed from the lithium preset to custom ones trying float voltages of 13.6 and 13.8, added slightly more draw by turning on lights inside the RV.

Any thoughts?

spray25 asked

0 Answers

How to determine full PV power during times when the MPPT is limiting PV power.

Watt from Solar-

How to know the total of watt generated before the reduction?

i understand that the SmartSolar will send only Watt-Volts-Amp when the batteries need it but i am curious to know what is the value before.. directly coming out of the panel

Any tips?

fenix asked
tijn1974 edited ·

1 Answer

100/20 mppt max amp input?

I have 10 panels, 40 volt, 5.6 amp and 5.9 short circuit amp. I want to configure it to be 80 volts 28 amps. I read that the max short circuit amps the unit can take is 20A, what does that mean and how would I trigger that (would simply connecting the panels destroy the unit or does there need to be a short somewhere?)

In short, would I be able to connect 80 volts at 28 amps to my 100/20 mppt?

bobster asked
kevgermany answered ·

1 Answer

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