Battery Charging

[Asheville]

I am getting ready to replace my house batteries on my 2102 AI non-ext Lounge. I have read that it takes 24 to 48 hours of charging on a 30 amp circuit to fully charge a battery that has bee used down to 50% or less. I have two questions:
1. Can you charge on a household 20 amp circuit and will it take any longer to charge versus on a 30 amp circuit?
2. Can you fully charge the batteries while you are driving (not plugged in to shore power) by a combination of engine battery and generator? Or is shore power the only way to get a fully charged battery?

Thanks

[Protagonist]

Originally Posted by Asheville

I am getting ready to replace my house batteries on my 2102 AI non-ext Lounge. I have read that it takes 24 to 48 hours of charging on a 30 amp circuit to fully charge a battery that has bee used down to 50% or less. I have two questions:
1. Can you charge on a household 20 amp circuit and will it take any longer to charge versus on a 30 amp circuit?
2. Can you fully charge the batteries while you are driving (not plugged in to shore power) by a combination of engine battery and generator? Or is shore power the only way to get a fully charged battery?

Thanks

The limitation is the amount of current used by the charger, which is less than 15 amps no matter what source of 120vAC power you're plugged into. So it will take the exact same amount of time to charge the batteries whether you're plugged into 15, 20, 30, or 50 amp power.

You can charge the house batteries from the engine alternator, from the generator, from shore power. If you have the stock Interstate solar panel and charge controller, it's best not to consider it as a source of charging power at all, but rather just as a means of keeping the batteries charged once you've charged them from another power source. The stock solar capacity is way too small compared to the battery capacity to consider it a viable charging source by itself.

[Boxster1971]

Yes you can charge off the engine alternator while driving as Protag mentioned. But this is not going to give you a proper 3-stage charge. Just consider it the initial bulk charging step then it should be plugged in to get a full proper charge.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[InterBlog]

Originally Posted by Boxster1971

Yes you can charge off the engine alternator while driving as Protag mentioned. But this is not going to give you a proper 3-stage charge. Just consider it the initial bulk charging step then it should be plugged in to get a full proper charge.


- - Mike
2013 Lounge EXT on 2012 Sprinter

An additional factor to consider is the TIME that it would take to achieve meaningful recharge using the engine alternator.

I don't know what that time would be on newer Interstates, but on our 2007 model, it would (for example) take about 4 hours of driving to go from an initial charge percentage in the 70's to something in the 90's.

What this means is that, for most practical purposes, our engine alternator cannot perform this function. If we were driving cross-continent and boondocking along the way, maybe. But not during our typical uses.

[NWGetaways]

So - I've wondered about this in the past. Considering that we have a quiet, powerful, low pollution source (the tow vehicle) right there with us, why can't this be modified to be an efficient charger that could replace a noisy heavy expensive polluting gas generator?

With a high output alternator, proper wiring, proper charger - couldn't this be done?

[LB_3]

No reason you couldn't charge using your towed vehicle. Just size (or oversize) your cables, use quick disconnect connectors in case you accidentally drive away in one or the other vehicle while plugged in, make sure you have good chassis grounds on both sides, and use a battery separator.

A lot easier said than done but not conceptually difficult.

[lewster]

Originally Posted by NWGetaways

So - I've wondered about this in the past. Considering that we have a quiet, powerful, low pollution source (the tow vehicle) right there with us, why can't this be modified to be an efficient charger that could replace a noisy heavy expensive polluting gas generator?

With a high output alternator, proper wiring, proper charger - couldn't this be done?

The proper equipment exists in the marine industry. There are several companies that offer this type of equipment, but the industry leader is BalMar. They manufacture alternators and external charge controllers that offer 3-stage charging that is extensively used on larger boats and yachts with in-board engine systems.

If you are seriously interested in this type of charging system, I would contact them to see if they have the equipment that provide what you are looking for.