How do I lower the high voltage in a 12v system after BlueSolarMPPT 100/30 charges a Battle Born 100amp Lithium ?

Question

question

tom53934 asked May 16, '19

How do I lower the high voltage in a 12v system after BlueSolarMPPT 100/30 charges a Battle Born 100amp Lithium ?

I have voltage of (18-20 volts depending on the sun) that goes through to my 12 volt electronics in the camper. I have NO inverter. Have a 200 watt panel on top, wired to a BlueSolar mppt 100/30-shunt-BMV 712-BattleBorn 100amp Lithium. The system works great until the BattleBorn is charged, then the voltage keeps climbing up. I have tried numerous resets and disconnected wires, have the mppt rotary dial set to #7, what should I do next or redo...lol? On the bluetooth app I can't find a 12v or 24v system setting. Oh the mppt stays in bulk after the battery is charged...tx...Tom

battery charging

2

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

tom53934 commented · May 16, 2019 at 12:49 PM

PV wiring on the left. Shunt has negative load on the right.

0 ·

20190516-073911.jpg (386.9 KiB)

JohnC ♦ tom53934 commented · May 16, 2019 at 01:11 PM

Yeh, I should have explained that you'll need a bluetooth dongle on that model mppt to change anything in there. Sorry..

0 ·

Modifications Space

Node Red Space

Answer 1 · 2019-05-16T12:41:23Z

JohnC answered · May 16, 2019 at 12:41 PM

In the app for the mppt, click on the 'Cog Icon', select Battery, and it should show. Good luck.

7

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

tom53934 commented · May 16, 2019 at 01:11 PM

Thanks John, I have been in the battery setting through the 'cog icon'. I have no battery option for 12v or 24v. I have just the BMV-712 app firmware v4.01, do I need another app specifically for the MPPT?

0 ·

JohnC ♦ tom53934 commented · May 16, 2019 at 02:07 PM

Same app, just a bluetooth dongle to connect to that mppt. And yeh, I hate recommending more expense, but there it is..

0 ·

tom53934 JohnC ♦ commented · May 16, 2019 at 02:10 PM

Thanks John, The only way to change the setting from 24v to 12v is with this dongle? https://www.amazon.com/Victron-Energy-VE-Direct-Bluetooth-ASS030536011/dp/B01CGFF8Q2/ref=cm_cr_arp_d_product_top?ie=UTF8

0 ·

JohnC ♦ tom53934 commented · May 16, 2019 at 02:20 PM

That's the one Tom. Sorry for the expense, but you may also see value in networking it to the BMV. Small consolation, but you really do need it anyway.

0 ·

tom53934 JohnC ♦ commented · May 16, 2019 at 02:39 PM

Thanks again John, I was at wits end, guess Victron designed it for a 24v European system. Should have bought the Smart MPPT...oh well another tech learning experience.

0 ·

JohnC ♦ tom53934 commented · May 16, 2019 at 03:11 PM

Just by way of explanation, your unit is designed for both V's. Depending on how it's initially hooked up, it will 'lock in' to a batt V and won't change by itself (there's a good reason for that - inadvertent changes in the field are not welcome). This incorrect primary setting could occur by powering up the panel side before the batts, but once locked in, job done. Older units might be 'retrieved' by powering down and repeating the startup procedure correctly. You could even try that, but likely a waste of time with a newer unit.

But I think you'll see value with full control & monitoring anyway, and I wish you well with it.

0 ·

tom53934 JohnC ♦ commented · May 16, 2019 at 03:50 PM

Ahh...I'm glad you explained that John. I know for a fact I was careful not hook up the PV until the mppt was wired to the batt. At the intial start up, the system went into bulk- absorption- float and life was good. Then in my curious way...the side of the camper that has been pre-wired for solar. Well I wired up a plug to adapt a small 50 watt panel (using to charge a Jackery) putting out about 20 volts. Now I'm thinking it over after what you said. Could that extra 20 volts of current change the mppt into a 24v setting?

0 ·

Answer 2 · 2019-05-17T03:30:40Z

JohnC answered · May 17, 2019 at 03:30 AM

Okaay. Now the real truth is revealed. :)

Remove the 50W intruder and see what happens. The mppt may well be working correctly, and when the Battle Born BMS? shuts down it's charge when full, the 50W panel is feeding just the downstream circuits with V that could go anywhere. With no current in your 12V system, the V could be expected to approach the Voc rating of the panel.

It's why panels should always have a controller. You could still use it to help charge before Absorb/Float V's are reached (it mightn't do much away from it's mppt optimum), but don't use it once the batt is up to V.

The mppt should show 0W once it's V settings are exceeded (barring a possible zero error).

4

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

tom53934 commented · May 17, 2019 at 12:40 PM

Hi John, The 50W Intruder (I like that) was hooked up for about 5 mins. I disconnected the mppt and reset the BMV712 after that curious move. That extra voltage must have changed the mppt to a 24V setting? Like you said that downstream V could have went anywhere, my newbie fault. Thanks for pointing out that the 50W panel should have a small controller. Yes your right, the mppt did show 0W after the V setting was exceeded. Any recommendation for a small controller? I'm thinking an inexpensive PMW or ?

0 ·

JohnC ♦ tom53934 commented · May 17, 2019 at 01:15 PM

Yeh, any-ole cheapy should do. Victron even still make em..

Not sure where your issue stands now, but it's good to see you having a go, and learning along the way. Keep asking if you need, someone here will always help such a personable fella as you.

Happy camping too..

0 ·

tom53934 JohnC ♦ commented · May 17, 2019 at 03:21 PM

John, I appreciate you taking your time to help me ;-)

I'll let you know how the system works after the bluetooth dongle is installed.

0 ·

tom53934 JohnC ♦ commented · May 21, 2019 at 11:41 AM

Hi John, Got the Victron bluetooth dongle installed and bingo, was able to change the mppt 100/30 from 24v to 12v. Thank you very much for pointing me in the right direction on my first solar install. Appreciate it, Tom

0 ·

question