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mrusmc53 asked

MPPT Bulk LED failure states insufficient power to start charging. What is solution?

I started with 4 Battle Born 240 AH and a Victron Multiplus II 12V /3000. added 6 - 220Watt solar panels through a combiner box, then a MPPT 150/85 Solar charger. Use a shunt BVM 712 to monitor. I've ordered a Cerbo GX, it will be a week before it gets here. I get a slow blink on the
Bulk LED stating system is powered but there is insufficient power to start the charging. The 5V spread to turn the charger on is working, there is plenty of solar harvest, averaging over 300 Watts all day long. What does insufficient power mean? How do I correct for insufficient power? The second question is the inverter overheats. The positive cable servicing the output of the inverter to the bus bar gets very hot if I am just living off battery, running 1 AC unit, Starlink, laptop, led light, and misc minor electronics. The function of battery only works well, just overheats, I put a coolling fan on the iverter box, but that's not enough,

battery chargingMPPT SmartSolarsolar
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Alexandra avatar image Alexandra ♦ commented ·

Where are you getting the insufficient power message from?

How are the panels combined? 3s 2p or 2s 3p?

If things are getting hot they are either loose, badly crimped or undersized.

3k @12v is 250+ amps so 95mm² cable at least should be there.

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mrusmc53 avatar image mrusmc53 Alexandra ♦ commented ·

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mrusmc53 answered · 4 secs ago

The solar panel are individually wired to a 6 position combiner box. Originally I wired them 3s 2p and thought that was my problem, but that change made no difference. On the solar charger, the Bulk LED flashes once every 3 seconds, the manual on page 11, section 3.10 LED indication. and on hot wire, They are 000. were the ones that were installed originally. the hot set is only from the inverter to the switch, switch to fuse, fuse to buse bar. after the buse bar all cables are just warm as they should be. My batteries will support my RV for over 8 hours. The installation of the solar has made no difference, telling me I'm not charging, and I cannot figure out what is causing that. I will recheck my cable crimping, sizing, and connections......again!!! ugh Thank you for your help,

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kevgermany avatar image kevgermany ♦♦ mrusmc53 commented ·
A screen print of the first screen of the charger from Victron Connect would help a lot.
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Alexandra avatar image Alexandra ♦ mrusmc53 commented ·
Are you sure the panels are wired ok? Checked each string separately with a meter?

The next thing is usually programming and firmware.

Sometimes the battery voltage on initial start up detects incorrectly then won't charge.

If you haven't programmed the solar and updated it then that may be the problem. As far as i am aware the rotary position 7 doesn't match the battle born requirements.

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mrusmc53 avatar image mrusmc53 Alexandra ♦ commented ·
clicked on the link to battle born, made adjustments to programing. Here's to hope tomorrow when the sun comes back, again thank you
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Michelle Konzack avatar image Michelle Konzack mrusmc53 commented ·

If you have 6 x 220Wp of solar panels, I suggest you to make two strings of 3 in series. and put both in parallel.


This will increase the power output from autumn to spring and also reduce the current on the wires, hence the losses


I assume, the solar panels have around 36Vmpp, mean roughly 6A each. this is 36A in total and depending on the cable lenght, you would need at least 6mm2 (or better 10mm2 or 16mm2).


And with a 3000VA invrerter on 12V, I would not install lesser then 2x50mm2 (better 2x70mm2) for the POSITIVE and NEGATIVE.


With a 12V System and this power, you have enormous losses

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mrusmc53 avatar image mrusmc53 Michelle Konzack commented ·
correctly wired a series parallel .... my electrical experience is with house electricity and a series circuit is almost non existent, so now I have 2 series circuits with 3 panels on each, huge difference!! My harvest is up to nearly 900 watts with voltage nearing 40 volts at 2:30 in the afternoon. with that said, if the system is resting, (5amps consumption, lights, chargers, gas refer) then I can see a 1% increase in capacity in 10 min. Not the plan.... I should be able to increase at a faster rate, plus the panels should handle my normal load of around 150A of consumption with an A/C unit on, minor lessers. or near that....

I have found lose connections.... a buse bar post at the bar, my main battery cut off post, on the back side was lose. I had a broken terminal in the combiner box. all new stuff with factory mistakes. SMH I have spent the day reviewilng and double checking every wire, every connection. All wire sizing is correct. new parts installed to replace broken, Now the question is how do I increase my harvest to overtake my consumption or get near it? What I have is not what I'm supposed to have


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delf67 avatar image delf67 mrusmc53 commented ·
150A @ 12V is 1800W consumption. 6x 220W = 1320W panels under perfect conditions (which you will almost never get). I don't see how you think generation is going to cover consumption?
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