12V battery only charging to 13.4

[wpns]

Some of these settings I have not messed with.

Well, first of all you have your battery capacity set to 40AH, when it's supposed to be 1,216 so it could be that the BMS thinks "I've put 40AH back into the battery, so I better slow down" or something.

 

[wpns]

I am thinking like a bent or ancient cable could cause power loss.

Well, yes and no. A cable (more likely the ends of the cable, where the lugs are crimped on) could have a high resistance, but that would most likely show up as reduced power to the thing it's powering.

A 'short' would either show up as tripped breakers or blown fuses (or a BMS OCP event, see below), it would have to be a very specific short to draw 30-40 amps (a few hundred watts) without starting a fire or generating enough heat to make itself better or worse.

Yes, you are getting BMS short-circuit alerts, but do those correlate to when you are deliberately turning the Discharge FETs off? Maybe the logging software doesn't have a way of distinguishing the two. Or yeah, maybe you have an intermittent short that's tripping the BMS OCP, but that wouldn't run your battery down.

 

[MakeMePower]

These are very aggressive for trying to troubleshoot.

If it was my battery, I would set charge voltage to 13.9 volts and verify that you can fill the battery with that charge voltage first.

I think you were being too impatient with your charging, OP.
50% starting SOC leaves 600 ah more to put in.
If you are only getting 20 or 30 amps out of your converter that means 20 or 30 hours worth of charging. With no loads.

Cell to cell imbalance will only expose itself above 3.45 volts per cell.

well considering she's isn't get even close to them I am not concerned. Her cycled Ah capacity is north of 1000, which means there doesn't appear to be any major issue.

The real question is why her usage is 10x what is normal , based off a few phones and a notebook.

the real question is what the real load is, is her charger only doing 30A because of voltage drop, or is it also supporting a 30A load on top of the charging (op you need to a dc amp meter at the charger as well, to see how much amperage the charger is putting out)

aggressive for me would prolly be a 500A charger minimum in this setup.

 

[MakeMePower]

Well, first of all you have your battery capacity set to 40AH, when it's supposed to be 1,216 so it could be that the BMS thinks "I've put 40AH back into the battery, so I better slow down" or something.

she's in open loop here, JK's can't throttle amperage.

 

[MedicineMom]

Change battery capacity to 1200

change start balance to 3.4

cell ovp to 3.63
soc 100 to 3.62
ovpr to 3.6
Max Balance Current to 2A

what size wire is run from the converter to the batteries, and what is the distance.

are you turning your inverter on and off multiple times a day?

take a picture of the first bms screen where it shows amperage. with the converter off, and your normal loads you use running. then turn off all the loads and take a photo of that

you need to try to get some heat in this bay, incandescent light bulbs or some furnace heat, you are on the bleeding edge of it shutting off.

I wondered if I needed to change the capacity or not. Since I clearly don't know what I am doing, I didn't mess with it. I will change those today!

Sometimes we do turn it on twice/day.

We got to 13.6 yesterday! Ran the generator the entire day.

The furnace pipes go under there, and it was colder last night and it didn't shut down. Maybe someone left a bay open the other night. I want to get some heat mats or something low power to keep them warm.

I looked at the BMS all day yesterday and with nothing on or plugged in, I was drawing 6amps. I thought I left the inverter off, but it could have been on. Started plugging things in and turning them on and everything else checked out good. Our furnace startup amps are about 22(with converter and inverter not in use) and running amps 16.

I am posting a picture of the screenshot you requested.

 

[MedicineMom]

she's in open loop here, JK's can't throttle amperage.

What does open loop mean?

 

[MedicineMom]

well considering she's isn't get even close to them I am not concerned. Her cycled Ah capacity is north of 1000, which means there doesn't appear to be any major issue.

The real question is why her usage is 10x what is normal , based off a few phones and a notebook.

the real question is what the real load is, is her charger only doing 30A because of voltage drop, or is it also supporting a 30A load on top of the charging (op you need to a dc amp meter at the charger as well, to see how much amperage the charger is putting out)

aggressive for me would prolly be a 500A charger minimum in this setup.

Why does it have to be a clamp meter on the cable? I'm gonna have to order a new one to get that reading. Which I can do this week. I wonder why the usage is high as well, and figured we need a different converter. The cables are 2awg I believe. We can't get anything bigger in the receiving ports on the converter. Do you have any advice on how to get bigger cables in there?


And how do we chase the large draw? We did a test at the main negative and only got 0.04 amps while turning breakers on. It'll probably be Tuesday before we can do another test. I was planning to do the same thing, but turn everything on one at a time.

Could a bad cable within our RV be the culprit? This thing is a 2003 all original wiring. We found one ground that was literally burnt. Obviously we replaced it but that signals these wires are probably on their way out, and corroded.

Do you have any charger recommendations? My husband did some research and it seems many people dislike the converter we have.

 

[MedicineMom]

Is it an AC clamp meter, or a DC clamp meter? AC clamp meter won't read DC, though a DC clamp meter will usually read AC.

DC. It's very old, a gift from my dad. So that could be why. They aren't expensive so I'll just have to get a different one. Would the reading at the connection be different than reading the cables themselves?

 

[MedicineMom]

These are very aggressive for trying to troubleshoot.

If it was my battery, I would set charge voltage to 13.9 volts and verify that you can fill the battery with that charge voltage first.

I think you were being too impatient with your charging, OP.
50% starting SOC leaves 600 ah more to put in.
If you are only getting 20 or 30 amps out of your converter that means 20 or 30 hours worth of charging. With no loads.

Cell to cell imbalance will only expose itself above 3.45 volts per cell.

We can't run the generator for 30 hours straight using no power. We use starlink internet for phone service, no service out here. We ran it for the entire day yesterday and got to 13.6. looks like we will need to get another charger to solve this problem.

This seems fairly simple though. I figured it was the charger. I believe we are drawing a little more amps than we should, so we're gonna have to chase that down. Maybe it's just an old RV. We will be out of the RV this spring and will run power to a permanent structure.

 

[MedicineMom]

Change battery capacity to 1200

change start balance to 3.4

cell ovp to 3.63
soc 100 to 3.62
ovpr to 3.6
Max Balance Current to 2A

what size wire is run from the converter to the batteries, and what is the distance.

are you turning your inverter on and off multiple times a day?

take a picture of the first bms screen where it shows amperage. with the converter off, and your normal loads you use running. then turn off all the loads and take a photo of that

you need to try to get some heat in this bay, incandescent light bulbs or some furnace heat, you are on the bleeding edge of it shutting off.

It's about 15 ft of cable, but we can't see any of it. It's under the floor, then goes to a relay which we can see, then to the batteries.

 

[MakeMePower]

It's about 15 ft of cable, but we can't see any of it. It's under the floor, then goes to a relay which we can see, then to the batteries.

if you can't see the wire, how do you know its 2gauge all the way? based on your voltage drop, I'm not sure this is the case

you need to determine where this 6A load is, that's not normal, has nothing to do with old wiring (my rv is from 1999, and the wire is fine shape).

you need your dc clamp meter to measure the difference between what your shunt is saying is going into the batteries, and what is coming out of the converter.

There is NOTHING wrong with your converter, I own a 9245 from them, and it outputs even more then rated.

again you need to determine how many AH in a day your consuming (this is where the shunt comes into play, it will track usage)

once you determine that, determine why your not seeing the 60A at the batteries, and determine where this 6A phantom load is coming from.

THEN you decide how long you want your generator to run, to replace the AH your using per day. You will probably be stacking chargers. Your bank is capable of being charged between 500A to 1200A.

doing any of these steps out of order will simply waste your money.

to answer your why can't I get past 13.6, simple. the charger is not giving enough amperage to replace what your using per day. you need to find all the loads and see if they can be reduced, if they can't we need to make sure the charger is outputting its max amperage. If it is, then we start adding chargers till it can get to full everday or every other day etc.

every single setting I told you in your BMS is NOT going to fix any problem, this is simply getting the proper limits in place. Fixing the loads and the charging concerns is where you need to focus


and again you said breakers, provide a photo of your breakers and dc fuse panel, breakers are not what are causing your issue, its will be on the dc side

 

[jeff.lankford]

Assuming all your DC loads are going through the RV distribution panel, I would track down the 6A base current by pulling all the 12V blade fuses in the panel until you isolate which circuit is pulling the 6A. FWIW, the baseline parasitic loads in my RV is about 0.25A. That's with CO detector, HVAC thermostat, radio and TV off/idle consumption.

And I suggest you try to measure the voltage drop while charging by measuring VDC at the converter output terminals, and then measuring again at the battery input. And get an accurate current measurement at the same time as you make the voltage measurements.

My 2000w inverter pulls 2.3A idle current if I forget to turn it off.

 

[MedicineMom]

Well, yes and no. A cable (more likely the ends of the cable, where the lugs are crimped on) could have a high resistance, but that would most likely show up as reduced power to the thing it's powering.

A 'short' would either show up as tripped breakers or blown fuses (or a BMS OCP event, see below), it would have to be a very specific short to draw 30-40 amps (a few hundred watts) without starting a fire or generating enough heat to make itself better or worse.

Yes, you are getting BMS short-circuit alerts, but do those correlate to when you are deliberately turning the Discharge FETs off? Maybe the logging software doesn't have a way of distinguishing the two. Or yeah, maybe you have an intermittent short that's tripping the BMS OCP, but that wouldn't run your battery down.

So I googled the SCP thing and aparantly it's a problem when you're inverter is off too long. The caps have no charge and the JK can detect the incoming power as a short. So we just flip all the breakers, plug it in and turn on the inverter then flip breakers. No SCP since.

I was aparantly using terminology wrong in regards to a short. What you're saying makes sense. What about a cable that something chewed through? Based on what you've said, I assume we would notice in the form of resistance, not power consumption.

We have had some sunshine and my husband said it hit 14V once!! We try not to let the battery go very low, 12.5 would be the lowest. Based on my math a FULLY charged battery should last us a few days. But that's 100-0 not 13.4-12.6. I have been closely monitoring when things turn on, and it seems a little high, but checks out. With absolutely nothing on we were drawing 2-3 amps though. Unfortunately we've been dealing with some other crap and haven't made the time to do draw tests.

 

[MedicineMom]

if you can't see the wire, how do you know its 2gauge all the way? based on your voltage drop, I'm not sure this is the case

you need to determine where this 6A load is, that's not normal, has nothing to do with old wiring (my rv is from 1999, and the wire is fine shape).

you need your dc clamp meter to measure the difference between what your shunt is saying is going into the batteries, and what is coming out of the converter.

There is NOTHING wrong with your converter, I own a 9245 from them, and it outputs even more then rated.

again you need to determine how many AH in a day your consuming (this is where the shunt comes into play, it will track usage)

once you determine that, determine why your not seeing the 60A at the batteries, and determine where this 6A phantom load is coming from.

THEN you decide how long you want your generator to run, to replace the AH your using per day. You will probably be stacking chargers. Your bank is capable of being charged between 500A to 1200A.

doing any of these steps out of order will simply waste your money.

to answer your why can't I get past 13.6, simple. the charger is not giving enough amperage to replace what your using per day. you need to find all the loads and see if they can be reduced, if they can't we need to make sure the charger is outputting its max amperage. If it is, then we start adding chargers till it can get to full everday or every other day etc.

every single setting I told you in your BMS is NOT going to fix any problem, this is simply getting the proper limits in place. Fixing the loads and the charging concerns is where you need to focus


and again you said breakers, provide a photo of your breakers and dc fuse panel, breakers are not what are causing your issue, its will be on the dc side

That's actually a good point. We only know what we can see but I don't think it's 2awg. I believe it's 4awg, there is two negatives and positives though.

We will order a clamp meter and do some draw tests as soon as we can. Got some other urgent things going on unfortunately.

I thought I posted a pic of the panel. The breakers are crappy 80 am flip breakers. All our breakers are the same style. Probably the cheapest we could find. We bought them when we had a different system setup.

This was very helpful and easy to understand the steps. I really appreciate your time and effort to help us out and stay safe.

My husband said he saw it get up to 14V when the sun came out. So you all are right, it has to be how it's charging. I'm glad you shared about your converter, because we don't know anyone else and so we didn't know if it was just junky.

 

[robbob2112]

short circuit/precharge needed
In your inverter caps are empty you need to pre-charge them before connecting up the battery. Disconnect the negative cable, put an old style light bulb, a graphite pencil, or a 30ohm 30w resistor basically anything that acts as a higher resistance to slow the charge.... once done it takes about 20 seconds... you just reconnect the cable.

if you have the battery disconnected the inverter has a drain resistor that disipates the charge in around 30 second typically.

Zap the inverter to many times and you can cause issues with it.


With nothing on you should be drawing nearly zero amps... like 1/4 amp or less...

You have something on that you don't realize... Have you pulled all your fuses and check the current draw as you put them back in? With everything off you will find a circuit that still has something that is actually on... a water pump, a light, an internal fan... something...

I would maybe start with the water pump fuse - measure current and pull it and see if that drops it to zero. If it doesn't drop to zero put that one back in and pull the next one ... any that drop it a bit are probably base load and you can check what it is... and if it needs to be on.

Also, start by flipping the breakers off one by one and see what they draw

and touch those flip lever breakers, if they are hot they are a hazard and could be burning your 6 amps because of it.

 

[MedicineMom]

Assuming all your DC loads are going through the RV distribution panel, I would track down the 6A base current by pulling all the 12V blade fuses in the panel until you isolate which circuit is pulling the 6A. FWIW, the baseline parasitic loads in my RV is about 0.25A. That's with CO detector, HVAC thermostat, radio and TV off/idle consumption.

And I suggest you try to measure the voltage drop while charging by measuring VDC at the converter output terminals, and then measuring again at the battery input. And get an accurate current measurement at the same time as you make the voltage measurements.

My 2000w inverter pulls 2.3A idle current if I forget to turn it off.

Oh dang good suggestions on how to test. I wouldn't have thought of testing for voltage drop. We did a similar test with the panel by flipping breakers, but didn't pull any fuses, again would have not thought of that. Looks like the draw is anywhere from 2-6 amps. So it's kinda variable which is odd to me.

I think my inverter is about the same, hard to be exact with a ghost draw somewhere lol

 

[MakeMePower]

Oh dang good suggestions on how to test. I wouldn't have thought of testing for voltage drop. We did a similar test with the panel by flipping breakers, but didn't pull any fuses, again would have not thought of that. Looks like the draw is anywhere from 2-6 amps. So it's kinda variable which is odd to me.

I think my inverter is about the same, hard to be exact with a ghost draw somewhere lol

That's actually a good point. We only know what we can see but I don't think it's 2awg. I believe it's 4awg, there is two negatives and positives though.

We will order a clamp meter and do some draw tests as soon as we can. Got some other urgent things going on unfortunately.

I thought I posted a pic of the panel. The breakers are crappy 80 am flip breakers. All our breakers are the same style. Probably the cheapest we could find. We bought them when we had a different system setup.

This was very helpful and easy to understand the steps. I really appreciate your time and effort to help us out and stay safe.

My husband said he saw it get up to 14V when the sun came out. So you all are right, it has to be how it's charging. I'm glad you shared about your converter, because we don't know anyone else and so we didn't know if it was just junky.

thats a main breaker added after the fact those are not factory, do you not have something like this, near the breaker panel?

 

[MedicineMom]

short circuit/precharge needed
In your inverter caps are empty you need to pre-charge them before connecting up the battery. Disconnect the negative cable, put an old style light bulb, a graphite pencil, or a 30ohm 30w resistor basically anything that acts as a higher resistance to slow the charge.... once done it takes about 20 seconds... you just reconnect the cable.

if you have the battery disconnected the inverter has a drain resistor that disipates the charge in around 30 second typically.

Zap the inverter to many times and you can cause issues with it.


With nothing on you should be drawing nearly zero amps... like 1/4 amp or less...

You have something on that you don't realize... Have you pulled all your fuses and check the current draw as you put them back in? With everything off you will find a circuit that still has something that is actually on... a water pump, a light, an internal fan... something...

I would maybe start with the water pump fuse - measure current and pull it and see if that drops it to zero. If it doesn't drop to zero put that one back in and pull the next one ... any that drop it a bit are probably base load and you can check what it is... and if it needs to be on.

Also, start by flipping the breakers off one by one and see what they draw

and touch those flip lever breakers, if they are hot they are a hazard and could be burning your 6 amps because of it.

We ended up flipping all the breakers when we turn it on, turning on inverter and then turning them back on. And that seems to work. We were nervous to charge the caps lol

There is definitely something going on. Someone else recommended pulling the fuses so we will definitely do that.

None of the breakers feel hot fortunately. Just checked em.

We will do these tests ASAP. I'm so thankful it's not the batteries!! We were so concerned since we arced them.

 

[robbob2112]

https://www.amazon.com/dp/B07RTTSC2V

If you get these you can use one to precharge the caps next time. The simplest is to attach wires to the ends and next time, before you connect the battery you connect it across the switch for 30 seconds, then turn the switch on.

 

[Yurtdweller]

That's fine, they are probably copper, which is highly conductive but bends easily. Be really careful with torque on the terminals, depending on your source (and acquisition timeframe) you can tear the terminals right off the cells if you are not careful"

Thread 'I WARNED YOU ALL! MB31/MB30 huge issue terminal snapping off'

Sep 18, 2024

Well well well, didn't I tell you all, you better wait for these new cells to establish some cred before buying ! Turns out the terminals are snapping off, now we don't know if these are EVE official terminals or a third party welding knock off terminals, but so far we know EEL, 18650batterystore, and maybe Nkon appear to have these in stock and they are basically popping off like coke can tabs:

So just like the fiasco of the v1/v2 280K cells, you better put...

• Alkaline
• Replies: 327
• Forum: DIY LiFePO4 Battery Banks

• 
• 

Idk if EVE installs studs. I don't think they do. I got studded cells from Amy Wan at Shenzhen Luyaun. Initially, I built my batteries without a torque wrench, and by the time I got the wrench and checked my assembly, I was surprised by how much more tightening they were able to handle. In 32 studs, I've had no failures.

 

[wpns]

Idk if EVE installs studs. I don't think they do

It looks like the terminals are a post-manufacturer laser-welding process, so it'll depend who did it. Not that EVE wouldn't put your choice of terminals on at the factory if you had a large enough order, but I want to guess their post-manufacturing process would be to test them and only put factory terminals on the Real Grade A cells for contracted customers, and let the failed-Real-Grade-A cells go to the aftermarket without any terminals.