Maybe if you had access to another inverter and everything behaved normally.. then you know that it’s the Multiplus...
Batteries keep dying.
- Thread starter Ibid49
- Start date
krby
Solar Enthusiast
Right, that says:
All About Low-Voltage Disconnect
Low-Voltage Disconnect is a feature of our Battery Management System to protect the battery from damage. Learn how to "wake up" your battery.battlebornbatteries.com
So I don't understand the -10VDC reading.
Yes, exactly - makes no sense. Especially when after disconnecting the inverter everything is suddenly ok again.
Ibid49
New Member
No, First of all, I haven't gotten the Inverter back from the service center yet. Should be getting here soon. Also, this Service Center is apparently Battleborn's go-to place, and they do all the programming there. I bought the Multiplus through Battleborn's site, and it came preprogrammed for their batteries. When I got it, there are only a couple of settings available through the Victron Connect app - switching the mode and maybe amperage limit? Everything else was locked down, and I didn't see everything I see in the Demo Library for the same device. Again it's not here atm, and I can't check it. I did buy the special USB cable that can connect to the Multiplus (forget what it's called) so I can use the VEConfigure software, but I haven't opened it yet.
Also, just to reiterate, even after disconnecting the batteries entirely, with the inverter just sitting by itself on the wall, I was getting continuity tone from the Positive to Negative battery lugs on the inverter. I left it alone for some 24 hours or so, and on the advice of my BB tech, reconnected it, and then the short wasn't there anymore.
At the time, no. Now I have a 100A circuit breaker in there (recent addition). At the time of the short and the -10 volt reading, I was already in troubleshooting mode. I was eliminating factors one by one, so at this point I had all other devices disconnected and was connecting the battery bank directly to the inverter. It was shorting out continuously, or at least for a good 10 seconds. I didn't leave it connected for more than that. I don't have a pre-charge circuit, I don't think. I don't even know what that is.
I did buy another inverter, and that doesn't have any of the issue that the Multiplus has, but I have only been running it for a few weeks. So if there's something that's slowly killing the batteries over the course of a year, I wouldn't be seeing a result from that yet. I am trying to work with my BB tech to find a method for testing to try to see this problem developing before it arrives at "dead." He's got me measuring the inter-bank cables between the batteries with a clamp-on amp meter once a month or so and recording the readings. But I don't know if that's going to be granular enough.
I completely understanding the inclination to think I'm crazy over the -10v reading. I considered that possibility myself for 30 long seconds while I was reading it. My multimeter is a cheapy from Harbor Freight, so ....? But it hasn't given me any reason to doubt it in any other case. And like I said, I checked it multiple times just to prove to myself that I wasn't crazy or dreaming. I know about switching the leads and getting negative readings. I wasn't doing that. All I can tell you is, I'm not an idiot, and I'm not careless. I double and triple check everything. Walk through the entire circuit every time before I flip the battery switch on to make sure I haven't done something stupid, make sure all nuts are snug and connections are good. I don't have an explanation for you, and if I read it from someone else on the Internet, I would conclude the same thing you did - that can't happen. All I can tell you is what I saw. Two batteries connected in series directly to the inverter with nothing else on the circuit other than the smart shunt (on the negative) and the battery switch (on the positive). 14.2 volts on the multimeter on the negative-side battery. Negative 10 volts on the positive side battery. 4.2 volts across them both. After I checked it several times I threw my hands up, disconnected the battery switch and went inside to spend the night in the dark. That's when I ordered the backup inverter.
Also, the "disconnect the inverter and everything's alright again" wasn't the Negative 10v reading. That happened with the the shorting out issue. Different times separated by..... maybe a week? The negative 10v reading resolved itself only have I got two new batteries shipped to me and connected everything back up again. I did use the Victron inverter a bit after that and everything seemed ok. But I was babying the heck out of it because I didn't trust it. Had the input amperage locked down to like 8 or 9 amps (AC), I think, in the Victron Connect app.
Are your batteries grounded..? I’m aware that this is a thing in some installations.. but many are not.. just thinking out loud really.. slow ground leak...
Ibid49
New Member
Also just for context, here's how the issue initially presented itself. Everything's been going great for a year. No issues - we basically know our system and know what it can handle almost intuitively. Not that we never run the batteries down to zero, but it's only maybe 3 or 4 times a year when we haven't checked on the batteries in a few days, and then the lights go out, and we're like "Oh yeah, that makes sense." Then we charge them back up to full and everything's fine again.
Only one night, my son and I were gaming and we knew we were running them down pretty low, but we were just wrapping up for the night when the lights went out. But when we checked, the SOC from the smart shut still said 11%, when that thing is pretty dang on most of the time - within a percentage point or two. So we thought it was weird, but we immediately ran the generator and charged the batteries back up to full and just chalked it up to a fluke. The next night the same thing happened, only at 32% SOC. Then the next night at 42%.
That's when I started getting serious about it, and the first thing I did was disconnect the batteries and try individually charging them with a 12v charger (AIMS, LiFePo4 setting), thinking it must be a balancing issue. But when I hooked them all back up, one of the four batteries was at like 12v I think (memory's getting fuzzy at this point), and another was at zero volts. Could my AIMS charger have done something? Maybe. It was acting a little weird and making some unusual clicking noises while hooking it up to the battery. It's been a trusty charger for a few years though, and I don't know why it would suddenly not be.
So that's when I started trying to limp along on just two batteries while I contacted BattleBorn, and that's when I had the shorting issue.
The incident the year before happened almost exactly the same way - suddenly and rapidly losing battery capacity for no apparent reason.
Only one night, my son and I were gaming and we knew we were running them down pretty low, but we were just wrapping up for the night when the lights went out. But when we checked, the SOC from the smart shut still said 11%, when that thing is pretty dang on most of the time - within a percentage point or two. So we thought it was weird, but we immediately ran the generator and charged the batteries back up to full and just chalked it up to a fluke. The next night the same thing happened, only at 32% SOC. Then the next night at 42%.
That's when I started getting serious about it, and the first thing I did was disconnect the batteries and try individually charging them with a 12v charger (AIMS, LiFePo4 setting), thinking it must be a balancing issue. But when I hooked them all back up, one of the four batteries was at like 12v I think (memory's getting fuzzy at this point), and another was at zero volts. Could my AIMS charger have done something? Maybe. It was acting a little weird and making some unusual clicking noises while hooking it up to the battery. It's been a trusty charger for a few years though, and I don't know why it would suddenly not be.
So that's when I started trying to limp along on just two batteries while I contacted BattleBorn, and that's when I had the shorting issue.
The incident the year before happened almost exactly the same way - suddenly and rapidly losing battery capacity for no apparent reason.
In the top loop there are 2 14V batteries. Voltage readings around the loop add up to zero Kirchoff's law). In the lower loop the left battery has shut down and now instead of being a current source it becomes a load. Again the sum of the voltages in the loop will be zero. This explains the voltage readings that OP had.
Ibid49
New Member
Actually, this might be close. My Multiplus is grounded to a proper ground rod just outside the battery box, which is the only ground in the whole system. But inside the house, there are a few LED lights that still glow when they're turned off, which I've read might be a grounding issue, but grounding is definitely magic to me - I don't understand it, just know to do it. We had an local electrician look at it last summer, and grounding the Multiplus was his recommendation. But the lights still glow with the switch off. The batteries sit on a thick rubber mat inside a wooden box on wooden legs. They are not grounded to anything other than through the inverter itself
As far as I can tell from Internet research, though, Having a single grounding point is the right way to do it, and the Multiplus' grounding lug seems the best option as far as I know.
It seems that grounding is one of those topics that is definitely open to endless discussion... I’ve read a bit of stuff about grounding... like yourself I don’t really have a grasp on it.. Victron def recommends grounding of inverter casings I believe.. and also I’ve read that one ground rod is best practice.. but other than that.. I wonder how to measure what’s being absorbed into the ground..?
Hawkeye52
New Member
This may be my first post here, but I have been lurking for a couple of years. Have you thought of adding a battery balancer to your system? I have four SOK 206 AH 12 volt batteries in series parallel for 24 volt. I use the Victron battery balancer for my system. Just a thought and observation.
Bing bing bing.
Looking through the thread to see, and you popped up with it.
Ibid49
New Member
I haven't thought of it. I guess I thought the BMS's would figure that sort of thing out, or maybe I thought that if I needed it Battleborn would have recommended it at some point. I will look into this new thing.
I’m wondering if the OP had monitored the batteries individually to see if they were staying in balance with each other. As said before throughout the forum. If you need 24 volt Lifepo4, get a 24 volts battery. Same can be said for 48volt.
Ibid49
New Member
Honestly this rings true to me in hindsight. But for what it's worth, I consulted Battleborn before I bought the batteries to see what they recommended, and this was their recommendation, (thinking back over 2 years ago) or at least they said it would work perfectly fine. But it does seem like the two strings of two adds complexity and points of failure that aren't necessary. I think if I had to do it all over again, I would rather do it your way, possibly keeping it to just one big battery if I could. Given what I have now, though, perhaps the battery balancer is the best option. And also, take Battleborn's advice with a grain of salt from now on. Though, I still think the Multiplus is acting weird too.
Ibid49
New Member
@Will Prowse per his request.
I’ve seen some info on their website about series use but can’t find it now. BB site is lacking. Basic rule for series, parallel charge first then assemble and use. Monitor and bring up the low battery individually with a 12 volt charger as needed. Several companies make balancers for 24, 36 and 48 systems that work well
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Ibid49
New Member
Hm.. found this which seems to suggest the battery balancer is at least not necessary or perhaps even not recommended? Depending on how you read his tone.
Daddy Tanuki
Solar Wizard
Will is a nice guy or I think he is having never met him in person, but you are 100% correct on the average and not so average person here on the forum... they are stuck in a bubble about how special they are...just like vegans.
Generalization much? I think the vast majority, especially those actively trying to answer people's questions, do so because they genuinely want to help out and don't think they're 'special' or 'in a bubble'. We all have different set-ups, different requirements, and trying to understand other's generally takes a bit of back and forth.
Q-Dog
¯\_(ツ)_/¯
You have a Smart Shunt, which means you have the ability to do midpoint monitoring. This can show you when the batteries are getting out of balance, and you can intervene to fix problemsbefore they get serious. Might be worth the time to do this for a few days to determine if adding the balancers might help ... or maybe simply reducing charge rate would help keep things balanced.
Or double the battery bank so you don't work the batteries so hard.
Or double the battery bank so you don't work the batteries so hard.
