big DC-DC (B2B) charger harms alternator and battery?

[Ascended]

Hi,
I want to install a Votronic B2B charger for my new camper-Van. It's available in a 30, 50, 70 and 90A Version. But most workshops and camper-manufacturers here in Germany only use and advise the 30A Version. But for my planed 280AH lifepo4 the loading-Time seems much too long for me.
The electric-guy from my workshop means that a big b2b Charger will harm the alternator, reduce the lifetime of the Lifepo4, and also the charger itself will not last for long. But for me, it seems like he just doesn't want to do install something else like he always does. I want to buy a Peugeot Boxer, maybe better known as RAM Promaster in the USA.
What's your opinion on this Topic? Do you have experience with "big" b2b Chargers?

Thanks a lot and sry for my awkward English

Dominic

 

[Theo74]

Hi Dominic, maybe it’s wise to ask Victron them selfs. They’ve got enough experience, and the Peugeot Boxer is the well known Fiat Ducato base on which a lot of RV’s in the EU are build, so they’ll know. You can send a message in German to udraeger(apt)victronenergy.com
I’ve done the same in the past with a different question towards the main office in The Netherlands, and or they will reply them selfs, or they will forward the question to one of your local German resellers, who will reply to you.

 

[labora]

Same challenge here. Unfortunately I am still waiting for the van - Fiat Ducato. I have serious doubts and questions. For example, when those intelligent alternators jump to lower voltage, can and do they still diliver all those Amps? I am about to contact Magneti Marelli about this. Fiat is not answering the phone when questions get complex.

 

[mikefitz]

. It's available in a 30, 50, 70 and 90A Version. But most workshops and camper-manufacturers here in Germany only use and advise the 30A Version.

Hi Dominic, all van manufactures have 'up converters' design notes that give information for motor home builders regarding what modifications are allowed to the base vehicle. The up to date Peugeot Boxer has a smart charging alternator with start stop engine management, the alternator will be rated at 160 to 180 amps maximum intermittent. Euro 5 vans had a 150 amp alternator
I have carried out tests on this vehicle. At engine idle speed the alternator delivers around 120 to 130 amps.
The vehicle systems require around 60 amps with everything switched on. In theory that is about 60 amps 'spare'.

The manufactures limits, on 'EuroVans' alternator loading, are around 40 to 50 amps, the largest seems to be the Ford Transit with the high output 250A alternator, at 70 amps. Peugeot/ Fiat fuse the 'converters' auxiliary feed at 50 amps.

The Votronic b to b charger takes in more current than it delivers to the battery, typically the 30 amp charger takes 35 to 40 amps from the vehicle, the higher current models take more. Euro 6 vehicles tend to have lower average alternator output voltages, thus the input current will be higher and the B to B charger work
harder, generating more internal heat. The Votronic 50/70/90 can be programmed to take lower currents,



There a number of issues if you exceed the manufactures allowed maximum current.

a) reduce reliability due to alternator overheating and failing.
b) compromise of vehicle battery charging (and start stop issues Euro6 vehicle)
c) warranty implications on a new vehicle.

electric-guy from my workshop means that a big b2b Charger will harm the alternator, reduce the lifetime of the Lifepo4, and also the charger itself will not last for long.

This guy is correct.

Ask yourself why the manufactures installs an alternator rated at three times more than the vehicle actually needs?

Mike

 

[DerpsyDoodler]

Just find out what the alternator is rated for, derate it by 30-50%, subtract 10-15 amps for overhead of the vehicle, then see what‘s left and size your charger according to that.

perfect information might let you size for a higher amp charger; but, in the absence of that, the above guidance should keep you from burning out your alternator.

 

[mikefitz]

subtract 10-15 amps for overhead of the vehicle,

This is way too low, this is only enough for the headlights!
Add the power needed for engine ECU, the air con, the heater blower power , the wipers , the turn signals, ABS breaking, power steering motor, charging the engine battery, glow plugs on a diesel, heated windows, heated seats.

Mike

 

[DerpsyDoodler]

This is way too low, this is only enough for the headlights!
Add the power needed for engine ECU, the air con, the heater blower power , the wipers , the turn signals, ABS breaking, power steering motor, charging the engine battery, glow plugs on a diesel, heated windows, heated seats.

Mike

You’re right. I may have grossly under-calculated this. All the more reason to be in touch with the chassis mfg.

 

[Bzzzt]

I have the Promaster with the 220 Amp alternator. I currently charge at around 100-120 Amps in winter and 50-60 Amps in summer. 30 Amps seems awfully low! I think it is acceptable to put the alternator under more stress. Similarly, driving the van puts the van under more stress than not driving the van! The question nobody seems to be able to answer is whether the alternator is temperature protected.

 

[SteveSS]

I also have a Promaster with a 220A (definately not smart) alternator. Smart alternators likely behave completely different, but this is how I dealt with the issue. Before I switched to lithium and bought a B2B, I never saw more than 90A pass through my simple battery isolator/combiner to charge my old 500Ah AGM bank. Rightly or wrongly, I assume that is my max available surplus. But I only bought a 60A B2B, because the instructions warn it can sometimes draw up to 1.5 times its rated output amperage (60 x 1.5 = 90). My new 410Ah lithium bank has a max charge rate of 100A, so 60A is safe there too.