Lithium battery flat after a long drive, why?

[Kups]

Last year after a small win on the lottery I bought a 110Ah lithium battery to replace my gel battery. My solar regulator, B2B unit and battery charger all had lithium settings so these were all reset to lithium and all appeared well on holidays.
However after a 300km drive on French motorways on Sunday we parked up at Le Touquet Aire prior to taking the tunnel home. We had stayed on a CCP site the night before with EHU (6amp) but no EHU at Le Touquet so LPG For the Alde Heating and fridge, 12volt from the lithium for everything else.
All appeared OK until we woke to no heating or 12volt. Lithium battery was flat but starter battery ok and engine fired up first time so starting to charge the lithium battery. We got home OK but I'm perplexed as to why the lithium had been drained when it should easily have lasted two or three nights without charging. I've charged the lithium at home via mains power with battery connected up normally. it's now up to 98% SOC, so assume that the battery charger is working correctly.
Any ideas why the lithium discharged so drastically? Is the smart alternator B2B unit a possible culprit? It's all factory fitted kit only the battery has been changed.

 

[Jo662]

Did you fridge, for some reason start taking its power from 12v instead of gas ?

 

[Kups]

Did you fridge, for some reason start taking its power from 12v instead of gas ?

It's a possibility, cannot exactly remember what the setting was when we woke up. It went to battery as usual when I started the engine. Pretty sure I left it on gas overnight . Might add that I filled up with french GPL during our drive up near Reims as I wanted a full Gaslow tank for the Aire stop. It was minus 3 overnight.

 

[Jo662]

We came home through France a few years ago,and for some unknown reason our fridge went to 12v when we were on a aire with no EHU. When we woke in the morning the leisure batteries were flat. It hadn’t happened before or since,very odd.

 

[LithiumConvert]

Sounds like something was left on. Most of us have had it sometime.

I guess you do not have an energy meter. I installed an NDS energy meter some years ago and it has been worth its cost many times over. I check the readings night and morning to make sure nothing is left switched on.

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[Kups]

Sounds like something was left on. Most of us have had it sometime.

I guess you do not have an energy meter. I installed an NDS energy meter some years ago and it has been worth its cost many times over. I check the readings night and morning to make sure nothing is left switched on.

Good point. I've a suspicion that I might have left the habitation heater pump on when we pulled up. Our mh has a separate heater pump that can be used to keep the living area warm on cold day drives. It's very quiet and I might have missed turning it off. It a toggle switch on the main panel but without an LED indicator.

 

[AdrianChen]

It's a possibility, cannot exactly remember what the setting was when we woke up. It went to battery as usual when I started the engine. Pretty sure I left it on gas overnight . Might add that I filled up with french GPL during our drive up near Reims as I wanted a full Gaslow tank for the Aire stop. It was minus 3 overnight.

Wonder if the gas was a butane/propane mix with too little propane? Might not work so well in -3c.

 

[ED O'DARAC]

Last year after a small win on the lottery I bought a 110Ah lithium battery to replace my gel battery. My solar regulator, B2B unit and battery charger all had lithium settings so these were all reset to lithium and all appeared well on holidays.
However after a 300km drive on French motorways on Sunday we parked up at Le Touquet Aire prior to taking the tunnel home. We had stayed on a CCP site the night before with EHU (6amp) but no EHU at Le Touquet so LPG For the Alde Heating and fridge, 12volt from the lithium for everything else.
All appeared OK until we woke to no heating or 12volt. Lithium battery was flat but starter battery ok and engine fired up first time so starting to charge the lithium battery. We got home OK but I'm perplexed as to why the lithium had been drained when it should easily have lasted two or three nights without charging. I've charged the lithium at home via mains power with battery connected up normally. it's now up to 98% SOC, so assume that the battery charger is working correctly.
Any ideas why the lithium discharged so drastically? Is the smart alternator B2B unit a possible culprit? It's all factory fitted kit only the battery has been changed.

Hi, we, too had this problem on our Adria Twin (weirdly, we were at Le Touquet as well!). Ours had stopped charging from the engine, so it didn't help if we drove around to try and charge.
We headed home and I eventually found that a hidden fuse had gone behind a plastic panel at the base of the RHS B pillar.
Replaced the fuse and it charged again whilst driving. These fancy new 'Smart' alternators are tricky as they don't charge all the time when driving. A pain! Good luck with yours.

 

[Kups]

Hi, we, too had this problem on our Adria Twin (weirdly, we were at Le Touquet as well!). Ours had stopped charging from the engine, so it didn't help if we drove around to try and charge.
We headed home and I eventually found that a hidden fuse had gone behind a plastic panel at the base of the RHS B pillar.
Replaced the fuse and it charged again whilst driving. These fancy new 'Smart' alternators are tricky as they don't charge all the time when driving. A pain! Good luck with yours.

Thanks, interesting post. Our Coral is charging the hab battery when driving so I'm now thinking it was the French GPL mix that the fridge didn't like and switched to battery.

 

[Kups]

PROBLEM SOLVED! The fridge fuse had blown and this then caused the flat battery (I understand).
No idea why the fuse blew - it's a 20 amp not 15 as originally installed. No obvious reasons for the fuse to blow, anyway all systems are go again.
Thanks for comments.

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[autorouter]

PROBLEM SOLVED! The fridge fuse had blown and this then caused the flat battery (I understand).
No idea why the fuse blew - it's a 20 amp not 15 as originally installed. No obvious reasons for the fuse to blow, anyway all systems are go again.
Thanks for comments.

I can't think of a way in which a blown fridge fuse could cause a flat leisure battery. I presume it was the fuse from the alternator/starter battery to the fridge 12V element.

 

[Kups]

I can't think of a way in which a blown fridge fuse could cause a flat leisure battery. I presume it was the fuse from the alternator/starter battery to the fridge 12V element.

I'm not sure of the routing but the fuse was the one on the electrobloc unit. Also don't know exactly when the fuse blew as I was using LPG for the fridge. It could have blown whilst driving that's why I suspected the smart alternator and B2B unit creating a surge somehow.

 

[Lizbiebrowne]

I had a similar experience with a KS Energy 120Ah Li battery. It would discharge to around 60% and then drop to zero. It turned out to be a problem with the BMS which I resolved by following a procedure supplied by KS Energy. Been fine since.

 

[Kups]

I had a similar experience with a KS Energy 120Ah Li battery. It would discharge to around 60% and then drop to zero. It turned out to be a problem with the BMS which I resolved by following a procedure supplied by KS Energy. Been fine since.

Thanks, mine is also a KS 120 Ah lithium. I'll get in touch with them tomorrow.

 

[Lizbiebrowne]

Thanks, mine is also a KS 120 Ah lithium. I'll get in touch with them tomorrow.

Here’s the email I had from them with the instructions:

Very sorry to hear you are having this issue with your battery.
A few things you can try to resolve this problem.
1. Run your battery voltage down to 10.2volts, the battery will shut down
2. Put it on a continuous charge to 14.4volts or 14.6volts this will allow the battery to
Re-collaborate and reset itself. The BMS (Battery Management System) will do all this.
3. Once it's reached full charge state, check your App, the result may not come through
Right away, so wait a few minutes
You may need to uninstall the App and reinstall it again and try it

If you can let me know how you get on with this.

Kind regards
Rob Silvera
KS Energy Batteries Ltd
Unit 323 Hartlebury Trading Estate
Beech Drive
Kidderminster
DY10 4JB
Tel: +44(0)1229 211193
sales@ksenergy.co.uk
www.ksenergy.co.uk

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[Kups]

Here’s the email I had from them with the instructions:

Very sorry to hear you are having this issue with your battery.
A few things you can try to resolve this problem.
1. Run your battery voltage down to 10.2volts, the battery will shut down
2. Put it on a continuous charge to 14.4volts or 14.6volts this will allow the battery to
Re-collaborate and reset itself. The BMS (Battery Management System) will do all this.
3. Once it's reached full charge state, check your App, the result may not come through
Right away, so wait a few minutes
You may need to uninstall the App and reinstall it again and try it

If you can let me know how you get on with this.

Kind regards
Rob Silvera
KS Energy Batteries Ltd
Unit 323 Hartlebury Trading Estate
Beech Drive
Kidderminster
DY10 4JB
Tel: +44(0)1229 211193
sales@ksenergy.co.uk
www.ksenergy.co.uk

Interesting and very helpful conversation with KS energy this morning.They advise that the circumstances of the fridge fuse blowing creating a surge caused the battery to go into protect mode. The recharging that I've done was the correct way to restore the battery so all looks OK. Still don't know what caused the fridge 20 amp fuse to blow, it's only happened once before in three years. The mysteries of motorhome tech!

 

[autorouter]

Interesting and very helpful conversation with KS energy this morning.They advise that the circumstances of the fridge fuse blowing creating a surge caused the battery to go into protect mode.

I said I couldn't think of a way that fuse could have blown, but there is the possibility of for example a problem with the chassis earths, which might cause all kinds of unusual current pathways. Worth checking the main chassis ground straps, to the engine and the starter battery, also to the leisure battery, and even the fridge negative return if it goes via the chassis.

There are other possibilities. A wire rubbing against a metal part, wearing through the insulation and touching occasionally. These things happen.

 

[VXman]

I can't think of a way in which a blown fridge fuse could cause a flat leisure battery. I presume it was the fuse from the alternator/starter battery to the fridge 12V element.

Hmm....tones of my ongoing saga???

Fridge on battery problem and engine not charging leisure batteries.

After a long drive yesterday I was surprised to find my batteries at only 70%. We have 350 watts of solar too. This morning I started the engine and noticed the Burstner/EBL display was down to 11.5. (just before it was 12.3) I then noticed the fridge 12vbattery light flashing. On checking I...

www.motorhomefun.co.uk

 

[Clive Mott]

Temperature sensor fault associated with the B2B unit.

 

[Kups]

Temperature sensor fault associated with the B2B unit.

Thanks, could you expand your comment.
Do you mean that there's a sensor in the B2B unit or the other sensors in the mh?
My B2B unit is close to the battery in an underseat locker which does get warm with the electrobloc unit in there as well.

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[eddie]

Dave, (the workshop manager at Van Bitz) told me after lunch one day he‘d been in Halfords to get wiper blades and the guy being served was told he should change headlight bulbs in pairs as the ‘voltage surge’ when one went will have damaged to other bulb.

The guy said OK, paid and left with two, Dave jokingly said “That’s one way of increasing sales“ and the guy said ”No seriously, its true”

 

[rob0114]

Had the same issue with a 239ah battery from fogstar - equally perplexed as OP when battery was flat in the morning after showing >200ah night before.

The explanation from Fogstar :

The issue with LiFePo4, is it difficult to determine capacity by voltage. The charge curve is so linear, and 13.4V could be 50% or it could be 75%. All the capacity is between 13.2-13.8V. An extremely small window. The way the BMS gets around this, and attempts to give you the most accurate percentage, is by counting all the amps you use, both in and out. It does not use voltage for its capacity and percentage measurements. This generally works quite well, however, one of the biggest drawbacks with this is the accuracy of the current it is counting. The BMS and most BMS on the market, cannot count below 1A.

I can see from the screenshot above, that the BMS is counting -0.8A, but it does this with no real accuracy, and this current will fade in and out, it will be counted, and then it won't. This is also true for small parasitic loads such as inverters etc that draw 0.2A pretty constantly, none of this will be counted in the percentage calculation. These errors can compound over time and result in the BMS getting a bit 'lost'. For example. you had 200Ah remaining previously and then all of a sudden, the BMS detected a low voltage, and it wasn't where it thought it was.

The way the BMS gets around this is when the battery is fully charged to 14.2-14.4V the BMS resets the counting and starts again. This means any errors are forgotten, and it's accurate again for the next few cycles.

I think what you experiencing, was compounding errors because the battery hadn't been fully charged for a while, coupled with low-current drains that are invisible to the BMS. The solution to this is usually a full charge, alternatively, there are expensive shunts that are more accurate than the one built into the BMS and do measure below 1A, but these are expensive.

Sorry for the long explanation, I just wanted to make sure you understood the limitations of the current counting.

Thanks,

Ben

This does fit with my use of the battery in that I left it at 80% charge when idle then normal use for trips away never charging to 100% therefore not resetting the BMS - little bit annoyed thats not pointed out in bold when you purchase it!


Away skiing soon so will quickly find out if theres anything else amiss!

 

[tonyidle]

Dave, (the workshop manager at Van Bitz) told me after lunch one day he‘d been in Halfords to get wiper blades and the guy being served was told he should change headlight bulbs in pairs as the ‘voltage surge’ when one went will have damaged to other bulb.

The guy said OK, paid and left with two, Dave jokingly said “That’s one way of increasing sales“ and the guy said ”No seriously, its true”

I think Dave was correct.

 

[drmartinwhite]

Last year after a small win on the lottery I bought a 110Ah lithium battery to replace my gel battery. My solar regulator, B2B unit and battery charger all had lithium settings so these were all reset to lithium and all appeared well on holidays.
However after a 300km drive on French motorways on Sunday we parked up at Le Touquet Aire prior to taking the tunnel home. We had stayed on a CCP site the night before with EHU (6amp) but no EHU at Le Touquet so LPG For the Alde Heating and fridge, 12volt from the lithium for everything else.
All appeared OK until we woke to no heating or 12volt. Lithium battery was flat but starter battery ok and engine fired up first time so starting to charge the lithium battery. We got home OK but I'm perplexed as to why the lithium had been drained when it should easily have lasted two or three nights without charging. I've charged the lithium at home via mains power with battery connected up normally. it's now up to 98% SOC, so assume that the battery charger is working correctly.
Any ideas why the lithium discharged so drastically? Is the smart alternator B2B unit a possible culprit? It's all factory fitted kit only the battery has been changed.

Logically, the lithium can not have been charged via the B2B sufficiently while driving. Something had to be draining the lithium. Likely culprit being your fridge. This could be for a number of reasons. Operator error, switching your fridge to battery overnight rather than Gas would be a probable cause.

In the other hand it you put your fridge onto battery while driving your B2B charging circuit should be sufficient to run your fridge while driving.

Our Hymer BMCT 600 is only a couple of years old but several months after revising the van we drove down through France and like you we were surprise to wake up in the morning to find the AGMs were depleted. At that time I put it down to operator error and assumed we put the fridge o. Battery rather than gas as newbies. We drove on and at the next stop the next day we put it on EHU and everything charged up, I didn’t think to check the hab battery state after the drive the next day. I forgot about this for the following year as we largely drove for campsite to campsite and the van went o to EHU. Then last Augmn we were driving from Yorkshire down to Southdown Motorhomes in Portsmouth to get the van serviced and stayed in the the marina car park overnight. We are now two years into owning the van and I like to think a little more savvy, and I noticed the hab batteries were again low. This is odd as the B2B should have charged them while driving. Only thing that can load the hab batteries while driving is the fridge, which we did have switched to batteries while driving as the B2B maintains that ok. Except it did not. Out with the multimeter, clamp meter and a bit of detective work and I figured out our B2B was dead! Based on the original story above from the year before I strongly suspected we have had a defective B2B form manufacturing, only noticed. This 2 situations as we largely don’t go off grid and use EHU, who knows. Hymer uses a Schaudt booster (B2B)and I had a diagnostics session direct with their techy guy Urdu Lang who co firmed my suspicions so I was able to present our dealer with such and the B2B is being replaced under warranty. As it happens our dealer then reported back to us the these Schaudt B2Bs had been failing regularly.

As I say, could be several reasons for your lithium’s being depleted, from operator error (fridge running on battery overnight) to defective B2B.

Hope that helps.

 

[Raul]

Interesting and very helpful conversation with KS energy this morning.They advise that the circumstances of the fridge fuse blowing creating a surge caused the battery to go into protect mode. The recharging that I've done was the correct way to restore the battery so all looks OK. Still don't know what caused the fridge 20 amp fuse to blow, it's only happened once before in three years. The mysteries of motorhome tech!

The fuse its just a thermal switch, it opens up the circuit like any mechanical switch. The fuse is calibrated to a fixed amp flow, any excess will open the circuit.
How can you get a surge from a fixed voltage source battery? Who is bringing in the extra voltage to create that surge? Not even a alternator can do that.
Autorouter's explanation is more plausible.

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