Portable battery Charger

[Lakejumper]

Can a RV battery be charged with a portable charger while plugged into shore power?

[Skibane]

Lwiddis wrote:
Lithium batteries can accept fast charge. One of their advantages.

Most AGM batteries can also accept a fast charge.

Many thin, closely-spaced plates connected in parallel = low internal resistance = fast charge acceptance

[valhalla360]

Lwiddis wrote:
Lithium batteries can accept fast charge. One of their advantages.

But Lithium are much more sensitive to bad charge methods...I would be hesitant to randomly hook up multiple charge sources.

[jaycocreek]

I use a Noco Genius smart charger also when boondocking and running the generator..

[wa8yxm]

I would suggest using a "Smart" type charger (I used a Deltran Battery Tender 2/20/70 amp model (20 was for battery charging then it dropped to tender) you do need to monitor it as it will not return to "Charge" automatically.. 70 is for jump starting and did not work well for me).

The most likely "worst case".. one of the chargers may refuse to go into "Battery charge" because it senses the other charger and thinks "Batteries full"

Other worst case.. already covered above.

[Horsedoc]

I have had two Schumacher chargers over the years. I don't recall models but both would shut down when the battery was fully charged.

[Lwiddis]

Lithium batteries can accept fast charge. One of their advantages.

[Lakejumper]

Thank you.

[valhalla360]

Yes, but there is a limit to the amps a battery can absorb, so typically, there is no reason to bother.

[time2roll]

Yes

[Skibane]

Sure!

Even if the battery charger in your RV's power converter is supplying some charging current to the battery, you can still connect a portable charger to the battery to charge it faster.

However, there is a limit to how fast you can charge a battery - particularly if it's the lead-acid variety. At some point, some of the charging current gets converted to heat, instead of charging the battery. Result: Excessive water loss, and possibly damage to the battery.

Most lead-acid batteries can accept a lot more charging current during the early portion of the charging process. As they gradually recharge, their ability to absorb charging current gradually tapers off.

For this reason, using several battery chargers may be more effective early in the charging process. Later on, just one battery charger may be sufficient to supply all the charging current the battery can accept.