Newbie battery charger questions
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Adding an inline fuse won't make it significantly larger.
It will need one of the moulded on BM2 connections snipping off and then a crimp connector to the fuse cable and a battery terminal crimping on to the other fuse cable.
Example from Amazon
Many people fit them without but my personal preference is to ensure they are fused, especially if they are out of sight in a flammable cupboard rather than a metal engine bay...
A possible middle ground is that you fit it it as is now to get to the bottom of any potential parasitic drain and if you find it useful enough to leave it connected long term through the season (I expect you will) then look at fusing it at that point.
It will need one of the moulded on BM2 connections snipping off and then a crimp connector to the fuse cable and a battery terminal crimping on to the other fuse cable.
Example from Amazon
Many people fit them without but my personal preference is to ensure they are fused, especially if they are out of sight in a flammable cupboard rather than a metal engine bay...
A possible middle ground is that you fit it it as is now to get to the bottom of any potential parasitic drain and if you find it useful enough to leave it connected long term through the season (I expect you will) then look at fusing it at that point.
I have fitted a BM2 and started off by fully charging the battery and monitoring it in the app. The result so far is pictured below. The reading after 5 days of 12.3v in the app is showing as 50% "low" and is equating to one orange light on the Van monitor (when I might perhaps have expected it still to be two orange lights until it reduced to 12.06v).
I will now recharge, remove all the fuses and redo the test to see if it lasts longer.
I will now recharge, remove all the fuses and redo the test to see if it lasts longer.
So, assuming the battery is healthy (and it may not be if it's been cycled a lot) you're losing about 50Ah in 120 hours, so just under half an amp (0.41A) drain on average.
That feels low for a fridge left on but is higher then you would expect for a "dormant" electric system.
It is in the order of something USB powered being left on, you've got 8 fused circuits have you identified what they are all for?
That feels low for a fridge left on but is higher then you would expect for a "dormant" electric system.
It is in the order of something USB powered being left on, you've got 8 fused circuits have you identified what they are all for?
Here is what we were told about the fuses:
Fuse One Module
1. Fridge 15AMP
2. Dimmer Switch 5 AMP
3. Splash Back 10 AMP
4. Kick Plate 10 AMP
Fuse Two Module
1. Poptop Top Light 3 AMP
2. Hob 3 AMP
3. N/A
4. N/A
We are pretty sure it's not the fridge and there is nothing obviously left on but pulling the fuses should tell us. We'll know next week.
Fuse One Module
1. Fridge 15AMP
2. Dimmer Switch 5 AMP
3. Splash Back 10 AMP
4. Kick Plate 10 AMP
Fuse Two Module
1. Poptop Top Light 3 AMP
2. Hob 3 AMP
3. N/A
4. N/A
We are pretty sure it's not the fridge and there is nothing obviously left on but pulling the fuses should tell us. We'll know next week.
Things I would be generally suspicious about would be dimmer switches that dimmed right down but didn't turn off or USB sockets (as they are active even when nothing plugged in)
However 0.4A is more than I would expect for those, unless one has developed a fault.
However 0.4A is more than I would expect for those, unless one has developed a fault.
I'd give it longer before drawing conclusions as that's not far off where you'd expect a normal wet battery to settle, if it keeps dropping it might be a sign of a cell internally shorted.
Before condemning the battery if you are able to isolate the battery entirely once charged and monitor it that might reveal any unfused load, maybe remove the negative lead but temporarily connect the BM2 to the post with a peg or small plastic clamp? Then you would know any discharge would be entirely due to internal reasons.
Before condemning the battery if you are able to isolate the battery entirely once charged and monitor it that might reveal any unfused load, maybe remove the negative lead but temporarily connect the BM2 to the post with a peg or small plastic clamp? Then you would know any discharge would be entirely due to internal reasons.
OK so I didn't let it go as long as previously but I hope this was long enough to draw a conclusion that the battery shouldn't discharge this quickly with nothing drawing power via the fused connections - latest graph below. It only took a few hours longer to reach this voltage level with the fuses removed than before.
So, I understand your final check though am a little nervous about disconnecting the battery terminal. The negative terminal is a little more difficult to access - do you suggest that because the negative will be earthed to the chassis and thus remove any shorting risk? Is negative earth standard these days?
If you think this is fairly risk free, I will try to give it a go.
So, I understand your final check though am a little nervous about disconnecting the battery terminal. The negative terminal is a little more difficult to access - do you suggest that because the negative will be earthed to the chassis and thus remove any shorting risk? Is negative earth standard these days?
If you think this is fairly risk free, I will try to give it a go.
It's standard in every T6/6.1 to use the van chassis as ground.
I suggest disconnecting the ground for a couple of reasons, it's the safest as if the wire touches the metal chassis it's all the same, it's the simplest way of breaking all circuits running from that battery as there will tend to be a single ground cable (as all the circuits tend to use the chassis ground) Vs lots of cabling on the positive.
Make sure the ignition is off so there is no chance of it being charged.Take the terminal off the battery post and wrap it in a rag/flannel/bar towel so it can't slide and touch anything. Easiest way to open the terminal is to loosen the bolt and then use a flat bladed screwdriver to open the "jaws" a bit.
I suggest disconnecting the ground for a couple of reasons, it's the safest as if the wire touches the metal chassis it's all the same, it's the simplest way of breaking all circuits running from that battery as there will tend to be a single ground cable (as all the circuits tend to use the chassis ground) Vs lots of cabling on the positive.
Make sure the ignition is off so there is no chance of it being charged.Take the terminal off the battery post and wrap it in a rag/flannel/bar towel so it can't slide and touch anything. Easiest way to open the terminal is to loosen the bolt and then use a flat bladed screwdriver to open the "jaws" a bit.
OK have disconnected the battery and here are some early results.
Already, this looks different, and I freezing overnight conditions much worse than previously.
I'll keep it going a few more days but confused over what this means. Something that isn't fused is draining the battery?
Already, this looks different, and I freezing overnight conditions much worse than previously.
I'll keep it going a few more days but confused over what this means. Something that isn't fused is draining the battery?
Overall that looks a lot better, settling pretty much where you would expect a standard flooded battery to be at full charge long term with no drain.
I'm curious what happened with the break around 01/09-01/10 - or is that where you disconnected so until then it was being maintenance charged by the Victron?
And yes that's the conclusion I would draw, something that isn't going through the fuse panel has a parasitic load on the leisure battery. Now you know that the next thing to do is to trace all the wiring to find out what those items may be and then try each one in turn.
As a first step might be worth reconnecting the battery but leaving the fuses all out and then going through everything you can think of trying switches to see if something is still on.
The two chargers (CTEK/Victron) probably have direct connection - or at least if they are fused they are not through the small consumer panel - but those are good brand named kit that's designed to be left connected. It's not impossible one has a fault but I'd leave those to last.
We haven't spoken about the fridge much, and I assume you have one. Is that wired through one of the fuses you can remove? I have a suspicion here as many of the common fitted compressor fridges are very sensitive to voltage drops on start up and it's not unusual for them to be as directly wired to the battery as possible. Also they tend to have an on/off switch that isn't a true "off" it tends to more like a standby switch.
I'm curious what happened with the break around 01/09-01/10 - or is that where you disconnected so until then it was being maintenance charged by the Victron?
And yes that's the conclusion I would draw, something that isn't going through the fuse panel has a parasitic load on the leisure battery. Now you know that the next thing to do is to trace all the wiring to find out what those items may be and then try each one in turn.
As a first step might be worth reconnecting the battery but leaving the fuses all out and then going through everything you can think of trying switches to see if something is still on.
The two chargers (CTEK/Victron) probably have direct connection - or at least if they are fused they are not through the small consumer panel - but those are good brand named kit that's designed to be left connected. It's not impossible one has a fault but I'd leave those to last.
We haven't spoken about the fridge much, and I assume you have one. Is that wired through one of the fuses you can remove? I have a suspicion here as many of the common fitted compressor fridges are very sensitive to voltage drops on start up and it's not unusual for them to be as directly wired to the battery as possible. Also they tend to have an on/off switch that isn't a true "off" it tends to more like a standby switch.
Also have a good look at your positive battery terminal clamp and maybe try and get some good pictures - how many cables are on there?
I'd expect:
If there are any additional smallish wires that might indicate something wired direct.
I'd expect:
- 1 x heavy gauge from the CTEK
- 1 x heavy/medium gauge to feed your fuse distro board
- 1 x medium gauge from the Victron
If there are any additional smallish wires that might indicate something wired direct.
Yes that's right. I charged it for several days via hookup before disconnecting and then reconnected the voltage monitor via a clamp.
So at nearly 5 days we are still at 12.68v.
With the fuses removed we were at 12.38v after 4 days so clearly different.
Looking at the wires on the positive terminal, we have 4 (plus the one to the voltage monitor so 5 in total). Difficult to see them all in a photo but here's the best I could do.
Two have yellow sheaths on the end and two red (the one coming front wards is the voltage monitor). I think the yellow ones are thinner wires. It's difficult to trace them of course as they run inside the paneling.
The fridge is supposedly on fuse 1 of the first bank (15A) and although I have no reason to doubt this I will do as you suggest when I reconnect and make sure it goes off with the fuse pulled. However, I doubt it's the fridge as there is no indication of, any kind that it's on when we turn it off.
So, theory is that the wires on the plus terminal are ctek, victron, fuses bank 1 and fuses bank 2. If this is right though, where is the parasitic drain? I guess I need to know if the two fuse banks are daisy chained or whether the 4th wire is a mystery connection.
Could I prove this by using a resistance tester on the battery plus terminal and pushing the other probe into an empty fuse holder? Thinking on, I guess I can only prove individual wires to the fuse banks versus daisy chain by taking off the positive terminal wires and testing individually. Any thoughts?
If there are individual wires to the fuse banks, don't we have a bigger mystery as there is no way to drain the battery with the fuses pulled?
Again, I greatly appreciate your assistance with this detective work.
With the fuses removed we were at 12.38v after 4 days so clearly different.
Looking at the wires on the positive terminal, we have 4 (plus the one to the voltage monitor so 5 in total). Difficult to see them all in a photo but here's the best I could do.
Two have yellow sheaths on the end and two red (the one coming front wards is the voltage monitor). I think the yellow ones are thinner wires. It's difficult to trace them of course as they run inside the paneling.
The fridge is supposedly on fuse 1 of the first bank (15A) and although I have no reason to doubt this I will do as you suggest when I reconnect and make sure it goes off with the fuse pulled. However, I doubt it's the fridge as there is no indication of, any kind that it's on when we turn it off.
So, theory is that the wires on the plus terminal are ctek, victron, fuses bank 1 and fuses bank 2. If this is right though, where is the parasitic drain? I guess I need to know if the two fuse banks are daisy chained or whether the 4th wire is a mystery connection.
Could I prove this by using a resistance tester on the battery plus terminal and pushing the other probe into an empty fuse holder? Thinking on, I guess I can only prove individual wires to the fuse banks versus daisy chain by taking off the positive terminal wires and testing individually. Any thoughts?
If there are individual wires to the fuse banks, don't we have a bigger mystery as there is no way to drain the battery with the fuses pulled?
Again, I greatly appreciate your assistance with this detective work.
The first photo looks like an Autoterm heater fuse holder.
Agreed. It’s the same as mine. I bet they go direct to the LB (maybe via a busbar) skipping any other fuse box you have. That’s how mine was done. Pic of mine below:
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