Charging with Alternator vs. Solar

[kcla]

Hi, I'm in the process of converting a van for long term travel (at least 1 year). I don't know if I'll be adding solar right away but have some questions about "fast charging" via the alternator/smart battery isolator. Any feedback is welcomed and appreciated.

- I've estimated apx. 150 amp hours per day use at max
- Looking at Renogy AGM/Lithium or Battle Born lithium
- Will charging via the alternator be detrimental to the battery?
- How long might it take to charge from the alternator?

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[Dzl]

First, I am far from an expert on the topic, so take what I have to say with a few grains of salt.

Will charging via the alternator be detrimental to the battery?

Vice versa, at least with lithium batteries, if you don't have a proper charger it is the alternator that can be damaged. Sterling Power, Victron, and Renogy all make products specifically to address this. Renogy also makes a charger that can supply both solar power and power from the alternator to the battery.

How long might it take to charge from the alternator?

Depends on the alternator, depends on the charger, and I'm pretty sure it depends on the engine RPM as well. Most of the chargers are rated for between 20-60 amps, a 20a charger would take 5 hours to supply 100ah, a 60a would take a bit over an hour and a half to supply 100ah, that is assuming your alternator is continuosly supplying the full rated capacity of the charger.

edit 1: upon further reflection, the numbers I quoted again are theoretical, in practice the 20a might not deliver a continuous 20a and same for the 60a, in 'bulk' mode they probably would, but in absorption and float (when your battery starts to get full), they might supply lower amperages.

edit 2: here is a thread on the sterling unit started by a fellow vandweller. lots of good info in there.

 

[tim0shel]

I would upgrade alternator also, looks like Dlz above already touched on that. I had mine upgraded and possibly will go with even larger one since they now build them up to 390amps.

 

[kcla]

First, I am far from an expert on the topic, so take what I have to say with a few grains of salt.



Vice versa, at least with lithium batteries, if you don't have a proper charger it is the alternator that can be damaged. Sterling Power, Victron, and Renogy all make products specifically to address this. Renogy also makes a charger that can supply both solar power and power from the alternator to the battery.



Depends on the alternator, depends on the charger, and I'm pretty sure it depends on the engine RPM as well. Most of the chargers are rated for between 20-60 amps, a 20a charger would take 5 hours to supply 100ah, a 60a would take a bit over an hour and a half to supply 100ah, that is assuming your alternator is continuosly supplying the full rated capacity of the charger.

edit 1: upon further reflection, the numbers I quoted again are theoretical, in practice the 20a might not deliver a continuous 20a and same for the 60a, in 'bulk' mode they probably would, but in absorption and float (when your battery starts to get full), they might supply lower amperages.

edit 2: here is a thread on the sterling unit started by a fellow vandweller. lots of good info in there.

Thanks so much, I really appreciate your input