Battery charging profile

[C846]

Hi, I’m new to this forum, but have been gleaning a lot of information from various posts and from the excellent article on batteries on the A and N Caravan Services website http://www.aandncaravanservices.co.uk/battery-technology.php.

 

I have a 2016 Rollerteam 747 on a Fiat Ducato chassis, which I’ve had since new and the electrics are as delivered. Having read the forums it now comes as no surprise to me that the original VARTA AGM battery is having serious issues holding a charge after only 3 years. I’m now considering replacing the leisure battery with a Yuasa L36-EFB.

 

My question is to do with the correct charging settings for the various devices in the motorhome.

 

The electrical setup consists of a Nordelettronica NE196-T Fuse box, which has charging inputs from both a Nordelettronica NE287 17A Battery Charger and a CBE PRS300 Solar Charge Regulator. The leisure battery is a VARTA Professional Dual Purpose AGM (840 095 085), Short Code: LA 95, 95 Ah, 850 A. The vehicle battery is a FIAMM (FIAT 51867871) 800 L5, 95 Ah, 800 A (I haven’t found much info on this battery, but I’m assuming it’s a standard lead-acid?).

 

Both the battery charger and the solar regulator have configurable settings for AGM, GEL & Pb Flooded batteries, however I’ve found that from the factory these are both configured for Pb Flooded batteries, despite the leisure battery being an AGM. Is this an error, or has it been intentionally set like this as there’s a mix of AGM leisure & Pb-flooded vehicle batteries? I imagine this certainly won’t have helped the life / capacity of the AGM battery.

 

So, onto the new setup if I buy the Yuasa EFB battery. What would be the recommended settings for both the battery charger and the solar regulator? Should an EFB battery be charged with a standard Pb-flooded profile? On the Alpha-Batteries website it states for the Yuasa L36-EFB that the Ideal Charge Voltage should be 14.4V and the Top Up Charge Voltage should be 13.6v.

 

The Solar regulator gives data for three scenarios (END-OF-CHARGE VOLTAGE / CHARGING COMPLETION TIME / MAINTENANCE VOLTAGE):

A (lead-acid): 14.1 V / 1h / 13.5 V

B (lead-gel): 14.3 V / 4h / 13.8 V

C (AGM and lithium): 14.7 V / 2h / 13.8 V

 

The battery charger doesn’t give specifics, but has the 3 main profiles for the different battery types.

If I used settings other than lead-acid, then would it affect the life of the vehicle battery?

 

Finally, the battery charger does not currently utilise the extra terminal whereby a temperature probe can be attached to the leisure battery in order to modify the charging cycle. If I can source a probe (NTC 10K@25 B3977 according to the specs) would there be much benefit?

 

Lots of questions, I know, but there are obviously lots of people on this forum who know their stuff!

 

Thanks,

 

Craig

 

[spirou]

The CBE solar regulator is worth about as much as it costs (~30€) but I wouldn't rush anywhere to replace it. What I would do is switch it over to B setting as that is closer to what Yuasa want for their battery and what nearly all other charger manufacturers set up as the wet-acid charge profile. Slightly higher voltage will just charge it a bit faster. 4h absorption limit is not excessive either. Since it's unlikely there's a huge array of solar panels sitting on top of your MH, it will rarely send significant current down to the battery so there's essentially no risk in cooking a battery with your solar setup. For some reason CBE is very conservative with their wet acid profiles i.e. low(er) voltage & short(er) absorption phase than pretty much everyone else. But that might be more of an issue with mains charging than small solar panels typically found on a MH.

 

What I find inexcusable is the poor documentation of nordelectronica gear. Not a single word on specifics of different charging profiles. So, unless you take out a multimeter and a clock, it's anyone's guess/experience what the differences are. What you'd be looking at is absorption voltage and duration. After the initial bulk phase is over (rising from 12V to 14+V) it will be held at a constant voltage somewhere over 14V for a certain period of time 1-8h) , then it will switch down to float phase somewhere under 14V. If the flooded charge profile voltage is close to Yuasa recommendations just use that. Voltage and duration both matter as it's a chemical reaction but not knowing the specifics it's impossible to guess what would be OK. That said, you're not going to destroy the batteries if you try different settings for 1 or 2 cycles to see what they do. Except that desulphation setting, read the manual before you try that but I'd avoid it altogether.

[spirou]

Ah yes, the battery temperature probe. Think of it as a fuse, not required for normal operation, very useful in case of abnormalities. Also extends the life of the battery slightly by adjusting charging voltage to the temperature.

[C846]

Thanks for the advice. It's just one 120W solar panel on the roof.

 

It looks like I might need to do some measuring whilst I've still got the old battery connected then (and I'm guessing it would make sense to disconnect, or chuck a blanket over the solar panel during the tests!).

That is, unless anyone else knows the parameters for the different settings on the Nordelettronica NE287 17A Battery Charger?

 

If I found a setting suitable for the Yuasa, would still be OK to use that bearing in mind that I think the standard vehicle battery is a normal lead-acid type?

 

 

 

Edit: I've also just read the following in the NE196_T fuse box / controller manual :

 

Recharging vehicle battery - The coupler relay recharges the vehicle battery with the battery charger when 230V power is provided.

The relay is excited when the service battery exceeds 13.5V and automatically drops out when

230V power is cut off or when the service battery voltage is below 12.8V.

[Derek Uzzell]

The standard starter-battery for your Ducato (FIAMM 95Ah, 800A) is ‘ordinary’ wet-acid type with removable cell-caps that will permit the battery’s electrolyte-level to be checked and (if necessary) topped up.

 

However, checking/topping up is not straightforward, as mentioned in the final posting here

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Battery-fitting/54196/31/

 

[spirou]

If Nordelectronica is anything like others then it probably charges the starter battery with a minimal current as that is all that is required and will hardly ever get to any high voltage where a specific profile might make a difference. So don't worry about it.

 

What bothers me, and it's symptomatic of most voltage sensitive relays/battery combiners, that disconnect voltage is 12.8V when a modern battery (AGM/gel/EFB) will have a resting voltage closer to 13V. Yuasa EFB is probably included. It means there will be a small current going towards the starter battery until that limit is reached, perhaps a while after EHU is disconnected, at which point the service battery will not be full even when you think it should be. It's not a huge deal but you'd think they'd figure out by now that there aren't that many MH batteries around anymore with resting voltages around 12.6V when this system worked at designed. It's just sloppy design, but obviously simple and cheap.

[C846]

Derek Uzzell - 2020-01-16 5:54 PM

 

The standard starter-battery for your Ducato (FIAMM 95Ah, 800A) is ‘ordinary’ wet-acid type with removable cell-caps that will permit the battery’s electrolyte-level to be checked and (if necessary) topped up.

 

However, checking/topping up is not straightforward, as mentioned in the final posting here

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Battery-fitting/54196/31/

 

Thanks Derek - yes, it's certainly not a 'normal' connection to the battery positive! I couldn't see the label on the vehicle battery, so I had to disconnect it to be able to check. The earth was an easy quick release, but the positive was quite daunting until I realised that the whole block on the positive terminal simply lifted off (once the main 10mm clamp was loosened and the two cross-head screws were removed from the red tabs!).

[C846]

spirou - 2020-01-16 6:19 PM

 

If Nordelectronica is anything like others then it probably charges the starter battery with a minimal current as that is all that is required and will hardly ever get to any high voltage where a specific profile might make a difference. So don't worry about it.

 

What bothers me, and it's symptomatic of most voltage sensitive relays/battery combiners, that disconnect voltage is 12.8V when a modern battery (AGM/gel/EFB) will have a resting voltage closer to 13V. Yuasa EFB is probably included. It means there will be a small current going towards the starter battery until that limit is reached, perhaps a while after EHU is disconnected, at which point the service battery will not be full even when you think it should be. It's not a huge deal but you'd think they'd figure out by now that there aren't that many MH batteries around anymore with resting voltages around 12.6V when this system worked at designed. It's just sloppy design, but obviously simple and cheap.

 

Thanks again - that's reassuring about the vehicle battery. Interesting comment about the 12.8v threshold as well.

[spirou]

In our previous van I had a gel battery with a resting voltage around 13.25V and the standard FIAMM starter battery which sits around 12.6V. With a VSR that disconnected below 12.8V it meant there was a 1-2A current until the gel got down well below it's full state. I guess it worked OK with its original battery but I just couldn't leave it as it was so I installed a manual switch but left the VSR in place in case the new owner forgot about the switch or installed another battery and it would work automatically as designed.

 

Let's say I'm happy to have a B2B booster now. Among other benefits it comes with ignition switched connection.

[C846]

spirou - 2020-01-17 8:13 AM

 

In our previous van I had a gel battery with a resting voltage around 13.25V and the standard FIAMM starter battery which sits around 12.6V. With a VSR that disconnected below 12.8V it meant there was a 1-2A current until the gel got down well below it's full state. I guess it worked OK with its original battery but I just couldn't leave it as it was so I installed a manual switch but left the VSR in place in case the new owner forgot about the switch or installed another battery and it would work automatically as designed.

 

Let's say I'm happy to have a B2B booster now. Among other benefits it comes with ignition switched connection.

 

That's an interesting idea to install a switch to restrict the starter battery charging when you don't want it to. Where did you place the switch & what current rated switch did you use? The J1 terminal of the NE196_T fuse box / controller goes to the vehicle battery, but it's protected by a 40A fuse.

[spirou]

https://www.amazon.com/Ampper-Battery-Disconnect-Isolator-Vehicles/dp/B07JJSTFMN

 

Something like that. It also served as an inverter disconnect switch and it was all located at the back of the van next to the gel battery. Unless you have very different batteries like mine were I wouldn't bother as the switch will itself have a slight voltage drop (0.1V if memory serves) and that's then a disadvantage while charging from alternator. When you get the new battery just see how it works out before doing any further work beyond testing different charge profiles.

[C846]

spirou - 2020-01-17 3:59 PM

 

https://www.amazon.com/Ampper-Battery-Disconnect-Isolator-Vehicles/dp/B07JJSTFMN

 

Something like that. It also served as an inverter disconnect switch and it was all located at the back of the van next to the gel battery. Unless you have very different batteries like mine were I wouldn't bother as the switch will itself have a slight voltage drop (0.1V if memory serves) and that's then a disadvantage while charging from alternator. When you get the new battery just see how it works out before doing any further work beyond testing different charge profiles.

 

OK, thanks again.

[C846]

A quick update!

 

I made various measurements with the NE287 battery charger, but I was getting some very strange and inconsistent readings. Upon further investigation it appears that the system was being affected by some pretty extreme voltage drops. This not only affected the mains / battery charging circuit, but also the solar circuit.

 

Although most of the charger wiring was 10mm2, there was a small section between the charger and the isolating switch that was only 6mm2. The habitation battery was not grounded to the chassis, meaning that there were also voltage drops on the negative line. The solar wiring was outrageous! There was a short run between the solar panel and the regulator and then a long run between the regulator and the habitation battery. This was even worse than I had originally thought. The wiring ran from the regulator (up by the ceiling) all the way down & round the van to the fuse/control box. There is an input for solar on the NE196-T, but this was not utilised. Instead, a block connector just attached to another long length of cable that ran all the way back round the van to the habitation battery; several metres in total!

 

I rewired the charger circuit with 16mm2 cable and 'modified' the existing solar cable so that it now runs from the solar panel (via a 20A trip / isolating switch where the old regulator used to be, for ease of isolation) straight down to next to the habitation battery where I positioned a new Votronic MPP solar regulator (on doing a bit of research I decided that this was a good investment compared to the old CBE one. This also enabled the 'trickle' charge connection direct to the vehicle battery). I also added an additional earthing ground connection for the leisure battery and doubled-up both the engine earth strap and the vehicle battery earth.

 

The result is that using the AGM setting on the NE287 charger I'm getting 14.4v for 2hrs, then 13.64v (with negligible voltage drop between the charger and the habitation battery). I'm also getting only about 0.04v voltage drop on the solar circuit and using the Lead Acid/AGM1 setting on the MPP250, which gives 14.4v for 0.5-4hrs then 13.45v. Both are perfect for my new Yuasa 100Ah EFB, which requires a charge voltage of 14.4v and a top-up of 13.6v.

 

Finally, re-reading the manual for the NE196-T controller, it only trickles charge from the habitation battery to the vehicle battery when connected to the mains, so there shouldn't be the leakage problem discussed a couple of posts back.

 

Thank you for the help and advice.