#2 Battery Voltage too high, Victron, Wattcycle 300ah

[Matsuhkr]

Currently I have a Victron 150/35 Solar Smart solar charge controller, charging a Wattcycle 300ah Mini (280ah). Absorption at 14.5v, float 13.6v. Haven't really charged it that many times, maybe 3 or 4, but it seems like I keep getting #2 Battery Voltage too High error in Victron. Whats causing this? Today it was being charged by two 410 watt solar panels. They are used panels, but typically put out around 330-350 watts. Somewhere around 90v. I've included a picture. It's showing 20v in the Victron app. I also have a Bluetti power supply from a AC200 that I was told I can use to charge it using a adapter to MC4 from AC. It puts out 58.8v @ 8A. Ive only been using the battery it to trickle charge my Ac200p or Anker power stations, or power a crappy 400w Coleman inverter to run some LED lights, nothing big.

Fairly new to these type of solar systems, if I'm doing something wrong please let me know. Thanks!

 

[740GLE]

Can you post the trends of PV watts and battery voltage for the past day?

Curious at how fast voltage went from say 13.8v to 20v as BMS went into protection mode.

My best guess is unbalanced cells, and cell over voltage protection causes the BMS to stop taking charge and voltage spiked.

Chance are you need to lower the charge voltage to a level where it avoids over voltage protection mode13.8v is ideal, then let it trickle charge <1A and hopefully let the SCC float and balance the cells.

The keep raising the charge voltage (but keeping low current) and watching if the BMS goes into protection mode.

 

[Matsuhkr]

Sure! Let me know if you need zoomed in ones. Thanks.

 

[Matsuhkr]

I don't see where the 20v is, the highest point is around 17.28v, which is still too high. I've also included the Voltage from the evening before until the point where I disconnected the small inverter. Is it normal for it to go from a little over 10v up to almost 11v ovrnight after disconnecting the load?

 

[740GLE]

So looks like the BMS went into protection mode around ~13.7v

I’d set absorption to 13.75v monitor battery voltage and adjust the voltage up little by little.

How did the battery voltage do over night? If you had no load on it it shouldn’t have dipped much lower than 13.2v

Having the battery at 10v means it’s at 0% SOC, you really should isolate any load from the battery and try and fix the unbalancing issues your facing.

 

[Matsuhkr]

Just got back to it. I should have disconnected the solar last night when I left. Here is how it did over night. The voltage spike at 723am was up to 17v. There's no error like yesterday though. The only load on it last night was the charge controller. I have to go out for a few hours, and then I'll report back. I set the absorption to 13.75v. Thanks.

 

[outboard1196]

Just got back to it. I should have disconnected the solar last night when I left. Here is how it did over night. The voltage spike at 723am was up to 17v. There's no error like yesterday though. The only load on it last night was the charge controller. I have to go out for a few hours, and then I'll report back. I set the absorption to 13.75v. Thanks.

If you have no other means of charging, set absorbtion 13.75v for 2 hrs and bump it up .1-. 2v each day till your at 14.2v
You can use the battery as usual, cycling will help.

 

[740GLE]

So the bad cell is kicking to over voltage protection very quickly, you didn’t even get 10whr into the battery before it went into protection mode.

I’d also reduce the charging current to 1a, see how it handles a slow trickle charge. We’ve already seen it can’t handle 17w without going into protection mode.

The goal is to slowly bumping the charging voltage without having voltage spike like it did this morning.

At resting voltage of 13.68v for 4 cells, that’s averaging out to a full battery if all cells are full (3.42), but I fear one cell is around 3.55v and others are closer to 13.37.

Even then you’re probably close to 95-98% full. So the last bit of this balancing might be a pain.

 

[Matsuhkr]

So the bad cell is kicking to over voltage protection very quickly, you didn’t even get 10whr into the battery before it went into protection mode.

I’d also reduce the charging current to 1a, see how it handles a slow trickle charge. We’ve already seen it can’t handle 17w without going into protection mode.

The goal is to slowly bumping the charging voltage without having voltage spike like it did this morning.

At resting voltage of 13.68v for 4 cells, that’s averaging out to a full battery if all cells are full (3.42), but I fear one cell is around 3.55v and others are closer to 13.37.

Even then you’re probably close to 95-98% full. So the last bit of this balancing might be a pain.Not really sure how this all happened. As you can see I've only put 17 kw of power into the battery in the two and a half months I've had

Can I specifically set the charge rate to 1a via the Victron? Or you just saying that's what I'm aiming to do with setting it at 13.75v (A x V= W) I don't have a variable rate power supply. The Victron is the only way I can currently charge it.

I've only put 17kw of power into the battery (From Victron) Not sure how this happened. I've only complete drained the battery 4 times (that I remember), 3 of them were slow charging other power stations at approximately 100w, 1 (most recent) was from the 400w inverter.

 

[740GLE]

You can it’s under the max charge current field in the SCC, it doesn’t look like a field you can edit and typically you wouldn’t want to reduce it, but your trying to fix the unbalance.

Here’s my 100/15 SCC

 

[740GLE]

I've only put 17kw of power into the battery (From Victron) Not sure how this happened. I've only complete drained the battery 4 times (that I remember), 3 of them were slow charging other power stations at approximately 100w, 1 (most recent) was from the 400w inverter.

That 17kwhr is lifetime of the SCC, 300ah 12v battery is about 4kwhr of storage, so that about checks out.

 

[Matsuhkr]

You can it’s under the max charge current field in the SCC, it doesn’t look like a field you can edit and typically you wouldn’t want to reduce it, but your trying to fix the unbalance.

Here’s my 100/15 SCC

Got it. I didn't realize that was a setting I could adjust. I don't specifically need to use the battery for the time being. How long do you recommend leaving it at 1a? Should I periodically increase the absorption as the other user suggested?

Also, can I disconnect the solar panels at night and hook up the Bluetti's power supply (58.8v @ 8a) to the Victron? That way I'm balancing overnight also. Thanks, I appreciate your help.

 

[740GLE]

Got it. I didn't realize that was a setting I could adjust. I don't specifically need to use the battery for the time being. How long do you recommend leaving it at 1a? Should I periodically increase the absorption as the other user suggested?

Also, can I disconnect the solar panels at night and hook up the Bluetti's power supply (58.8v @ 8a) to the Victron? That way I'm balancing overnight also. Thanks, I appreciate your help.

Keep it 1a and play around with absorption voltage, bump it by 0.05v watch the current respond, if the voltage doesn’t spike again, keep raising the absorption voltage. Soon as it spikes lower the absorption voltage.

For now I’d keep with just PV.

Do you have any load you can apply to the battery? It would t hurt to draw off some Whr to help bring that run away cell back down.

 

[Matsuhkr]

Keep it 1a and play around with absorption voltage, bump it by 0.05v watch the current respond, if the voltage doesn’t spike again, keep raising the absorption voltage. Soon as it spikes lower the absorption voltage.

For now I’d keep with just PV.

Do you have any load you can apply to the battery? It would t hurt to draw off some Whr to help bring that run away cell back down.

The biggest 12v device I have is the 400w inverter. I have 12v fridges, and smaller power stations I could charge at around 100w. I've been holding off buying a bigger inverter because I was considering a buying a second Wattcycle battery for a 24v setup instead of 12v. With this current issue it doesn't seem ideal though since I know I should use matched batteries, but do to financially constraints, I have to buy things when I can.

 

[740GLE]

See if you can send 1a into the battery, if you can’t without hitting over voltage protection, draw some load off of it and try again.

 

[Matsuhkr]

See if you can send 1a into the battery, if you can’t without hitting over voltage protection, draw some load off of it and try again.

So I had bumped the absorption up to 13.85v (from 13.75) over the course of the last 45 mins @ 1a. It never switched from float of 1-2w, so I'm going to drain a bit and see if it will switch back to absorption. I think that's what you wanted me to do. Hopefully I'm understanding

Edit: Rereading, I think maybe you wanted me to keep raising the absorption voltage and see if it hits over voltage. I only pulled a little power off so now it's bulk charging at 13-14w @ .9-1a still at 13.85 absorption

 

[mikefitz]

It never switched from float of 1-2w

It may help if you set float volts , ( as a temporary measure), to the same value as absorbtion volts whilst you are trying to Inprove balance .

 

[740GLE]

So I had bumped the absorption up to 13.85v (from 13.75) over the course of the last 45 mins @ 1a. It never switched from float of 1-2w, so I'm going to drain a bit and see if it will switch back to absorption. I think that's what you wanted me to do. Hopefully I'm understanding

Edit: Rereading, I think maybe you wanted me to keep raising the absorption voltage and see if it hits over voltage. I only pulled a little power off so now it's bulk charging at 13-14w @ .9-1a still at 13.85 absorption

Mike also has good advice.

Many people feel you can use the same absorbtion voltage as float voltage. If you do this you wouldn’t want to go much above 13.8v but that’s assuming you have balanced cells.

 

[Matsuhkr]

It sat around 13.81 for around 45 mins. That was @ 13.9v Absorption and 13.6v float. I ran a 100ish load for 4 mins to get it to start bulk again at around 13.40v. Set absorption @ 14v absorption and still at 13.6v float and 1A. It bulk charged at 14w until battery hit 13.98v after 45ish mins, now it's floating at 2w. Battery voltage slowly dropped over 40 mins now to about 13.93v. Going to be running out of sun here in a bit.
Is there something else I should be doing with it? Don't want to be wasting your guys time.
For what it's worth, I went back through the history for the last 30 days (that's as much history as I have) and it's always given me a high voltage warning every time it's been fully charged. I don't see anywhere in the trend of it ever getting to 20v (spiked to 14.79v) but thats what the max voltage shows. I've included screenshots of the furthest I can go back (25 days). I guess the battery's probably been like this since I got it.

 

[740GLE]

My guess is the battery was never balanced so you were always hitting over voltage protection.

I’d say it’s good that you didn’t hit over voltage protection while trickle charging it.

Draw some load as you want on the battery then tomorrow up the current to 5a with the same voltage, then continue upping the voltage once it hits float.

 

[Matsuhkr]

My guess is the battery was never balanced so you were always hitting over voltage protection.

I’d say it’s good that you didn’t hit over voltage protection while trickle charging it.

Draw some load as you want on the battery then tomorrow up the current to 5a with the same voltage, then continue upping the voltage once it hits float.

Will do! Thanks for you help. I appreciate it.

 

[Matsuhkr]

Nothing exciting happened today. (Story of my life ) I was kind of busy so I only drained it down a bit and left it to charge a few times. I was charging at 5a and kept bumping the absorption voltage but a little each time it got to float. I'd then drain it down a bit and let it charge back up. Last absorption was set to 14.25v. Should I be changing the float? It's still at 13.6v. I'll try to bump absorption a few more points tomorrow as well. Attached screenshots in case they have relevant information. Seems better, but not sure if that's only because of the low amperage charging. Should I keep doing this until I get up to 14.6v

 

[740GLE]

At 14.25v it looks like it never hit over voltage protection.

If you can keep bumping to 14.3-14.4v without hitting over voltage protection I think you’re golden, leave absorbtion at 14.4, leave float at 13.6v.

The idea that you need 14.6v for 100% is kind of pointless.

I’d say draw a huge load on the battery then adjust charge current back to 35a and see what she can take for current while charging, you shouldn’t hit over voltage protection.

One thing I’d add would be a victron smart shunt (300a would be perfectly fine) and add it to the battery, and have it talk to the SCC via VE.Smart network (BT to BT) coms. This will allow you to properly track SOC.

 

[Matsuhkr]

So it hit over voltage today. Had absorption at 14.4v @7a. Bumbed it up in the middle of the day from 5a because I knew it it wouldn't have enough sunlight today to fully charge. Not that that's hugely important, but I wondered to see. I had to use it a little bit more than I planned last night. Looks like it spiked right a 14.36v. I'll drain a little bit off tonight drop it back down to 1a and try again at 14.4v. Unless you have another recommendation. Thanks again!

 

[740GLE]

14.4v vs 14.35v is minimal in SOC.

Your plan sounds good, if not lower the voltage 14.35 (at higher current) hopefully it can sit at that voltage for a while and trickle charge.