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lukedermody avatar image
lukedermody asked

Issues with Victron set up in a Van after inactivity

Hi,

Any insight is greatly appreciated and thank you in advance.

I own a VW Vanagon that is set-up with a 100w solar panel, MulitPlus Compact 12/2000/80, SmartSolar charge controller MPPT 75/10, isolated DC/DC converter Orion-Tr 12/12-30, BMV-712 smart battery monitor, and two AGM 12-170 batteries. The system powers some small lights, a single burner induction stovetop, a small water pump, a small fridge and one outlet. Typically everything gets plenty of power from the solar panel, but will charge from the car battery when running if needed.

We just got our van back from repairs that took 5 months. When we got the van back the solar was disconnected and none of the systems had been used for the 5 months. For context, everything was installed in 2020 and worked perfectly fine until this.

Since getting the van back a few days ago, I reconnected the solar panel thinking everything had to charge back up. Everything works perfectly fine when the car battery is on, and the van has been driven for a few hours which would typically charge everything. However, when the car is off and relying on solar/house batteries, the MPPT will not turn on (even with the power switch "on"). During the day, all the lights still work and the app is reading about 7-10W of solar (it's been cloudy) and 9-12V on the battery. If I try to turn on the stovetop or outlet, the MPPT red alarm light starts to blink and those appliances don't work. Once the sun sets, nothing will work without the car battery on (lights included).

I've done a ton of research but I simply do not have enough knowledge to figure out the best next-step. Does anybody have any recommendations before spending money on a technician to come out? Should I connect the batteries to shore power and try to charge them that way?

The screenshots below were from nighttime for reference. Can add more tomorrow if that's helpful.

Thanks,

Luke

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AGM Batterybatterylifemultplus
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klim8skeptic avatar image klim8skeptic ♦ commented ·
@lukedermody 2 circuit breakers next to the mppt are open. ??

Those circuit breakers are known to cause problems, getting hot, tripping or voltage drop across them.


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kevgermany avatar image
kevgermany answered ·

Assuming reconnections made correctly.

Were the batteries disconnected before the van was laid up?

A screen shot from the MPPT would help.

Most likely the batteries are deeply discharged and may be damaged. External AC to the Multiplus and leave to charge for a couple of days then test again

Your battery capacity is set at 600Ah, yet you have 340Ah of battery, but this isn't the cause.

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lukedermody avatar image
lukedermody answered ·

Hi @kevgermany , thank you for the response.

The batteries were not disconnected... The repair was originally only supposed to take a few weeks and the mechanic said he would disconnect anything he needed to (my mistake in hindsight). The only connections I found disconnected were the 2 wires leading directly from the solar panel. I just attached a photo of these, as well as a screenshot of the MPPT. During the daytime, the MPPT has been reading 7-10w of solar, 9-10v, and 0.6-0.9A.

Noted on the battery capacity settings, thanks.

I will try connecting the Multiplus to shore power tomorrow and leave that for a couple days. That was my hunch on what to do next but I wanted to confirm that is safe to do with batteries that are deeply discharged.

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kevgermany avatar image kevgermany ♦♦ commented ·
Looking at the battery voltage from the MPPT clip, I'd be surprised if they recover. But worth a try.

Which voltage are you quoting, battery or solar?

MPPT won't start to charge until the panel voltage is at battery voltage +5V. About 18-19V for an AGM in good condition.


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lukedermody avatar image lukedermody kevgermany ♦♦ commented ·

@kevgermany It indeed appears the batteries are toast. With everything else working when the van is running, theoretically should two new batteries do the trick? Is there anything else within the system that could have been affected by the deep discharge? And is replacing the batteries as simple as disconnecting and reconnecting the same way? I’ll likely have an electrically-experienced friend do the swap for me, but he’s not familiar with victron. Any insight on this would be greatly appreciated.

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pwfarnell answered ·

Your BMV settings are mainly for lithium batteries but your equipment list states you have AGM. You may be better if you changed the BMV settings to the following as well as the correct capacity noted above.

Charged voltage 14.2V
Discharge floor 50%
Tail current 2% (lower may be possible with AGM depending on how well they are performing)
Charged detection time 5 min
Peukert exponent 1.20 (lower may be OK with good AGMs)
Charge efficiency factor 90% (Good AGMs may well be OK with a higher value)

The higher Charged voltage setting is because you have solar, in poor light the solar may increase your voltage to say 13.6V and charge with a low current, the BMV set at 13.2V would interpret this as fully charged and reset to 100% before your batteries were charged. Setting the charged voltage to 14.2V makes sure that your batteries get to full voltage from solar before the BMV resets to 100%.

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kevgermany avatar image kevgermany ♦♦ commented ·
It's actually on the defaults for these batteries.
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xe99 avatar image
xe99 answered ·

i have killed AGM batteries in less than two months by leaving them in a partial state of charge. they absolutely need to be recharged immediately after use. if they were disconnected with even a very small load and drained down, their capacity is most likely shot. a capacity test would confirm. the victron stuff and even LED lights and appliances will have a small vampire load that constantly draws from the batteries unless a disconnect switch is used or the batteriies are disconnected. also, keep in mind, a near dead battery will show 100% SOC and a normal voltage until you apply a load to it, which your inverter/cooktop would certainly do, and deplete to a lower voltage very quickly. an AC hob is a heavy load so its no surprise it wouldnt turn on. My guess is that your batteries are completely toast and will need to be replaced. the fact everything works when running the engine supports this. i have tried recovering AGM's with no success. maybe time to think about lithium, although you still need to be careful not to let them drain down and sit at a near zero SOC.

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lukedermody avatar image lukedermody commented ·
Hi @XE99 , thanks for the response. It indeed appears the batteries are toast. With everything else working when the van is running, theoretically should two new batteries do the trick? Is there anything else within the system that could have been affected by the deep discharge? And is replacing the batteries as simple as disconnecting and reconnecting the same way? I’ll most likely have a more electrically-experienced friend do the swap for me, but he’s not familiar with victron. Any insight on this would be greatly appreciated.
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xe99 avatar image xe99 lukedermody commented ·

No, nothing else should have been affected. Victron equipment is top notch and very well made. There is no component i see in you list that would suffer from being turned off. Replacing the batteries and re-check or change your settings if you go with a different battery chemistry is all you need to do and continue with your normal routine. Be mindful though that if you replace them with AGM's again, try to keep them at a high state of charge as long and as often as you can. AGM's really dislike being left depleted and can be damaged quickly. Personally for the cost of AGM's -vs- lithium, i would not replace them again with AGM's. It really would be worth your time to research and think about going with lithium. Especially because your type of usage would be the type that would constantly put the batteries in a partial state of charge. lithium batteries could care less and can be left in a partial state of charge for long periods of time with no negative effect, as long as you dont deplete them to near zero and leave them that way. Its a little bit of a learning curve and takes some time to understand and implement a lithium battery, you cant just drop any old lithium battery in you van, there are special considerations to make and it may require re-arranging your system a bit, or adding some minor new gear, but you will thank yourself later believe me. Its like going from the stone age to the bronze age.

Also, just a little nitpick, those water hoses over the inverter are in a very bad location. if one of them ever starts to drip or leak, you could maybe destroy the inverter.

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kevgermany answered ·

If you do replace the batteries with lithium, you also need to change the settings to match.

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