Battery And Charging Advice Appreciated

[t0mb0]

There's a guide PDF file within this link, with an explanation as to why the Ablemail functions in this way @t0mb0 . Interesting info, if it's your kind of thing.

EURO 5 and EURO 6 battery charger selection and smart alternator operation explanation | 0161 745 7697

Oh yeah, that’s interesting. Once the starter is above 80%, the ablemail relies on regenerative braking spikes to start up a 3 minute cycle of charging. Probably ok unless you’re on consistently clear roads. The three minute timeout also explains why it can run for a while after the ignition is off. Using an actual ignition trigger would be less hit and miss though, but to use that sense line in that way means you’d presumably have to lower the voltage threshold because the ignition feed wouldn’t hit the alternator high voltage consistently.

 

[t0mb0]

Okay, so the best thing to do would be to fully charge my battery, reset the NASA and see how it behaves. How do I fully charge my battery, and how do I check it? Can I do this through the hookup and EC155 PSU (I have a vague recollection that the EC155 isn't much cop at fully charging the battery?), or would I need a standalone charger connected to the mains. If so, could I hookup on my drive then connect a charger to the 240v socket inside the van and then charge the battery?
I've also got the problem that I'm going to have to lift my seat to get access to the battery terminals, so I need to do something here, perhaps rig something up that allows me to access the battery through the panel on the rear of the seat base.

Sorry, I don’t know anything about that EC155. The ablemail *should* fully charge it over a long run.

 

[t0mb0]

I've just read the NASA BM1 manual, where in the FAQ, it states:

Q Why does my BM-1+ show a higher capacity immediately after charging than it does after a few minutes' discharging?

A This is an unavoidable feature of battery chemistry, which varies from battery to battery, and the charging regime used.

This sounds like it explains the behaviour you are seeing. It's very odd though, and implies to me that the BM1 isn't a pure current integrating device with explicit full battery detection. My victron monitor is such a device and it definitely doesn't have this behaviour.

 

[mmi]

I shouldn't be dropping the battery below 50%?

I think it's a question of interpretation...

When battery life expectancy (in cycles) vs depth of discharge is plotted one can think how it fits use profile. The graph below tells that you can cycle a battery e.g 500 times from 100% down to 0% - or 1150 times from 100% down to 50%. That was an extreme example but just to show that lead-acid batteries actually tolerate significant amount of abuse. Certainly the trick is not to leave the battery at discharged state but recharge soon.



This is because battery life depends on the total energy throughput that the active chemicals can tolerate. Ignoring other ageing effects, the total energy throughput is fixed so that one cycle of 100% DOD is roughly equivalent to 2 cycles at 50% DOD and 10 cycles at 10% DOD and 100 cycles at 1% DOD.

More to read ---> Battery Life and How To Improve It at about middle under paragraph "Depth of Discharge (DOD)".

 

[travelvolts]

You should re set your NASA at least every two months to retain accuracy and I wouldn't pay too much attention to what the Sargent tells you. You shouldn't really need to charge from the mains if you drive the van regularly. The Ablemail will charge your battery to 100% easily. There is nothing not right if turning on lights pulls your battery down to 75%, unless, you are using high wattage filament lamps? What does the voltage read on the BM1 when you turn the lights or other loads on?

 

[KR.]

I'm driving the van back/forward to my work every day, a journey of 5 miles or so in total, not a great deal. Once every 10 days I'm doing a run up north of anything between 200 and 500 miles in total. I've never reset the NASA so will look into that - how do I calibrate it to my battery if I don't know the current battery state?
I've just sat in the van, engine off and switched things on while monitoring the meter, voltages backed up by EC50 control panel LEDs, % and amperage from the NASA only.

Start, after a run to the shops this morning of 2 miles, my last decent run was about 250 miles return 6 days ago, other than that work and back.
95% / 12.9v / 0.1A
LED lights only
95%/12.8v/1.5A
which dropped to
80%/12.6v/1.5A within 5 mins where it appeared to stabilise.
additionally HS2000 heater on, dropped to
73%/12.4v/3.6A within 3 minutes
additionally Fridge on, dropped to
55% /12.0v/8.8A within 5 minutes where the drop appeared to stabilise
switched Fridge off, increased to
60% / 12.2v/3.3A where it appeared to stabilise
switched heater off, increased to
65% / 12.3v / 1.3A where it again appeared to stabilise.
Switched off lights and panel
70% / 12.4v / 0.0A
Gone back out to the van after 5-10 minutes
75% / 12.5V /0.0A

At the point I'm sitting in my van in winter with the monitor saying 55% battery capacity with freezing temperatures overnight I'm not happy!
I've got some money to fix this but that doesn't mean I want to fling it away...

 

[t0mb0]

I'm driving the van back/forward to my work every day, a journey of 5 miles or so in total, not a great deal. Once every 10 days I'm doing a run up north of anything between 200 and 500 miles in total. I've never reset the NASA so will look into that - how do I calibrate it to my battery if I don't know the current battery state?
I've just sat in the van, engine off and switched things on while monitoring the meter, voltages backed up by EC50 control panel LEDs, % and amperage from the NASA only.

Start, after a run to the shops this morning of 2 miles, my last decent run was about 250 miles return 6 days ago, other than that work and back.
95% / 12.9v / 0.1A
LED lights only
95%/12.8v/1.5A
which dropped to
80%/12.6v/1.5A within 5 mins where it appeared to stabilise.
additionally HS2000 heater on, dropped to
73%/12.4v/3.6A within 3 minutes
additionally Fridge on, dropped to
55% /12.0v/8.8A within 5 minutes where the drop appeared to stabilise
switched Fridge off, increased to
60% / 12.2v/3.3A where it appeared to stabilise
switched heater off, increased to
65% / 12.3v / 1.3A where it again appeared to stabilise.
Switched off lights and panel
70% / 12.4v / 0.0A
Gone back out to the van after 5-10 minutes
75% / 12.5V /0.0A

At the point I'm sitting in my van in winter with the monitor saying 55% battery capacity with freezing temperatures overnight I'm not happy!
I've got some money to fix this but that doesn't mean I want to fling it away...

You don’t have any possible source of incoming current over this period, no solar, no mains, no ablemail? Assuming there isn’t any incoming current then the BM1 reading is just plain wrong because the SOC is increasing at points. I notice your SOC is varying with voltage, which is expected behaviour for a cheap voltage only SOC meter but the BM1 is meant to integrate actual current flow. Check it’s installed correctly...

 

[t0mb0]

You don’t have any possible source of incoming current over this period, no solar, no mains, no ablemail? Assuming there isn’t any incoming current then the BM1 reading is just plain wrong because the SOC is increasing at points. I notice your SOC is varying with voltage, which is expected behaviour for a cheap voltage only SOC meter but the BM1 is meant to integrate actual current flow. Check it’s installed correctly...

I was interested in what's going on here, so I rang the manufacturer of the BM1 for an explanation. It's actually expected behaviour for the device that the SOC can increase after the load decreases (even without current flow in) because it corrects for the Peukert effect (google for details...) very actively. So, when you get a serious load, e.g. the 9amps from your fridge, the SOC is calculated assuming that this load will persist indefinitely until the battery is empty, and this SOC (because of the Peukert effect) is lower than the effective SOC for a low current draw. When this load stops, the monitor then has to correct its previous pessimistic reading and increase the SOC. It's kind of technically correct under the assumption that the current flow will persist indefinitely - but that assumption itself is pretty dubious in a van where the current draw can bounce around all over the place. What this effectively means is that you shouldn't trust the reported SOC too much when the current flow has been varying recently. I'd just use your van as normal, and if you get any long-term indications that you are frequently running low, investigate options then (which might well mean a solar panel assuming your battery is in good condition).

 

[KR.]

I was interested in what's going on here, so I rang the manufacturer of the BM1 for an explanation. It's actually expected behaviour for the device that the SOC can increase after the load decreases (even without current flow in) because it corrects for the Peukert effect (google for details...) very actively. So, when you get a serious load, e.g. the 9amps from your fridge, the SOC is calculated assuming that this load will persist indefinitely until the battery is empty, and this SOC (because of the Peukert effect) is lower than the effective SOC for a low current draw. When this load stops, the monitor then has to correct its previous pessimistic reading and increase the SOC. It's kind of technically correct under the assumption that the current flow will persist indefinitely - but that assumption itself is pretty dubious in a van where the current draw can bounce around all over the place. What this effectively means is that you shouldn't trust the reported SOC too much when the current flow has been varying recently. I'd just use your van as normal, and if you get any long-term indications that you are frequently running low, investigate options then (which might well mean a solar panel assuming your battery is in good condition).

I really appreciate your time here and have got a rough understanding of the variable SOC. The problem is that I've had these indications for the best part of a year, and cannot have any confidence that the battery will hold up enough to provide me with minimal heating and lights during the upcoming winter. I think I'm going to have to replace the battery and fit an external power socket to the front of my house somewhere that will make charging it up on the drive much less hassle.
Thanks to all!

 

[KR.]

Just done an early morning 40 miles up the motorway, pulled over just prior to the motorway to see charging voltage at 13.8v, charging current 1.6A and SOC 76%, engine on. Parked up, engine off after 45 minute drive, Ablemail green light flashing, SOC 76%, voltage 13.8v, charging current 1.4A.
I thought the Ablemail was pushing 30A charge into my battery?

 

[t0mb0]

Just done an early morning 40 miles up the motorway, pulled over just prior to the motorway to see charging voltage at 13.8v, charging current 1.6A and SOC 76%, engine on. Parked up, engine off after 45 minute drive, Ablemail green light flashing, SOC 76%, voltage 13.8v, charging current 1.4A.
I thought the Ablemail was pushing 30A charge into my battery?

It will only push 30amps when the battery is relatively empty. As the battery fills up, the current it accepts naturally reduces. If the charging current is 1.4amps, it suggests the battery is pretty full - probably more full than the 76% the monitor is suggesting.

 

[t0mb0]

You can see the actual voltage/current charging profile in the pdf doc linked to in the ablemail page linked to earlier in the thread. That multistage charge profile is how all decent lead acid chargers work.

 

[KR.]

Thanks again, I've looked at the ablemail literature and if the green light is flashing then the battery should be charged and it's in the float stage at 13.8v. Assuming the Ablemail is operating correctly then everything is ok, bar the NASA monitor which I've powered on/off and reset the capacity to 110ah, watched it slowly climb to 104% then reduce to 100%. I'll now monitor it, fingers crossed the problem is there.

 

[travelvolts]

I think the BM1 has led you up the garden path. From the voltages that you have given I would say that your battery is behaving normally and that the Ablemail is doing its job. I have never been very impressed with the NASA monitors and ditched them long ago in favour of the Victron BMV series.

 

[t0mb0]

I think the BM1 has led you up the garden path. From the voltages that you have given I would say that your battery is behaving normally and that the Ablemail is doing its job. I have never been very impressed with the NASA monitors and ditched them long ago in favour of the Victron BMV series.

I agree, I have a victron bmv and it definitely doesn’t have the ‘bouncy’ SOC estimate that the BM1 seems to have.

 

[mmi]

Could do the "real thing" - measure (a part of) actual battery capacity.
A DIY procedure could be e.g. the following:
1) Record the voltage and the time since engine was on.
2) Switch on a steady/constant load of approx. 5 A (60W). E.g. a H4 or H7 driving light bulb is good enough for this purpose.

3) Record the voltage and the current.
4) Then every two hours record the voltage and the current.
5) At 10 hours record the voltage and the current. Switch off the load. Now you presumably have drained approx. 50 Ah from the battery. For more accurate value calculate the average of the recorded currents thus [average current x hours] gives Ah's drained. Presumably you should now have the battery at approx. 50% SOC.
6) Let the battery rest at least 4 hours (without load) and measure the voltage.
7) The result: If the battery still would have another 50 Ah to go the voltage reading (at #6 after the 4 hour rest) should be minimum of 12.0 Volts.

(Unfortunately) there are quite a few different tables in the internet how to evaluate this. A few are copied into thread ---> Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?​

 

[KR.]

One last bit of advice required please gents. I've bought a Victron bluesmart charger 12v/10A, I've installed an outside socket next to my drive parking spot and the plan would be to regularly place the leisure battery on charge. The leisure battery is under the seat and a tight fit so I aim to remove the seat and fit a quick disconnect connector permanently to the battery and connect the charger as required. It would be a case of plugging in the hookup, plugging the charger into the onboard 230v socket and connecting this via a quick disconnect to the battery.

The Victron comes with clamps and M8 eyelet connectors (quick disconnect leads). The leisure battery is an Xtreme XR1750 AGM.

Before I take the seat off do I need a different quick disconnect lead?

Edited to add : My van has an EC155 PSU/charger, I take it that the charging component will need taken out the loop altogether as I'm sure I can't have both connected.

 

[travelvolts]

The Sargent charger is pretty useless so just switch it off or remove the fuse. You might want to change the ring terminals on your quick disconnect for 6 mm ones to suit the XR1750.

 

[KR.]

The Sargent charger is pretty useless so just switch it off or remove the fuse. You might want to change the ring terminals on your quick disconnect for 6 mm ones to suit the XR1750.

Good, I see Halfords has the 6mm ring terminals in stock nearby, I could keep the Sargent switched off but thought it needed to be on as it's providing the mains power for the charger through the hookup? Is it possible to isolate the charger side of the PSU leaving the van 230v sockets available?
Getting there!

Edited, I've looked at the paperwork for the EC155 and can see a fuse marked charger (15A) on the bottom right, I'm assuming if I pull that one then I can still use it as a standalone power supply/distribution but the charger won't be in the loop anymore?

 

[Salty Spuds]

Good, I see Halfords has the 6mm ring terminals in stock nearby, I could keep the Sargent switched off but thought it needed to be on as it's providing the mains power for the charger through the hookup? Is it possible to isolate the charger side of the PSU leaving the van 230v sockets available?
Getting there!

Edited, I've looked at the paperwork for the EC155 and can see a fuse marked charger (15A) on the bottom right, I'm assuming if I pull that one then I can still use it as a standalone power supply/distribution but the charger won't be in the loop anymore?

Why not just hard wire the Victron into the van & leave permanently connected to the battery?