battery charging> which is best

But in short nothing on earth beats constant voltage charging for minimum time spent generator running

Annoying hum

Having to remember it's on

Gasoline Cost

Hauling gasoline

Having to refill the tank

Vector, Outback, Magnum, Vehicle alternator, you name it - they all come up losers in a race with a qualified power supply operating at the correct voltage.

If I had been limited to gizmo charging of my battery bank I would have starved to death or been the victim of a self-inflicted gunshot wound long ago.

With a generator Time Is Money. Period

gocamping14 wrote:
which method of charging a battery would be the fastest and most efficient when off the grid.

a. plugging the camper into a generator, running of course. (110v line)

b. plugging camper into the drive vehicle and running the engine.
(reg. 7 pin connection)

c. using a battery charger accessory on a generator running.

your thoughts, thanks............

ss

a) if you mean charging with the rig's on-board converter, then Abs voltage is everything. For example, at 14.6v (boost), my pm4b-45 would be putting out it's 45a limit, but when it dropped to 13.6 Vabs, current would drop to about 19a, and taper from there... thus adding several hours to the charge time.

b) charging via the vehicles alternator requires heavy cabling, otherwise excessive voltage drop will have the same effect as mentioned above, in a).

c) generators are very limited in their charging-amperage abilities, compared to the size of ac-dc charger they can support. I think someone said an eu2000i charges at 8a... compare that to running a 60a, or even a 75a(pfc) charger... 2-3 hrs vs. a day or two.

The problem is, there's not much available in the way of chargers, in the 50-100a range, so converter-chargers are usually the least expensive way to go. But you need one that holds a decent Abs Voltage (say 14.4-15.0v). On the flip side, there are lots of adjustable voltage bench power supplies available in the say 10-36a range, at very reasonable prices. And a good, reliable 40a portable is hard to find... the vec1093dbd being the leader of its class, it seems.

Yet another reason to move the batteries inside.. more stable temperatures for charging and no decrease in available AH due to the cold.

Lessee----

Now what little inexpensive critter can be voltage adjusted easily to render constant voltage charging on an amperage scale that is meaningful?

Hmmmmmm?

I've seen 13.1 to 13.9V float based on temperature.

14.8V at 25C or 75F. See a battery manufacturers recommendations for temperature corrected charge voltages, if you want the absolute correct answer. I camp in temperate regions, not too hot, or not too cold, in my 3 season travel trailer. 14.8V is near enough for me in most all situations. Might be light on a cold morning, but that's the whole idea, charge first thing in the morning, and temperature is less likely to be an issue on that 14.8V recommendation.

Yes, temperature correction enters the equation. 14.8 volts is not appropriate when camping at Point Barrow on Valentine's Day,
Too cold need higher voltage

nor Death Valley Junction on the 4th of July.
Too hot need lower voltage

It's chemistry.. The reactions between the electrolyte and the plates, change ,
Cold equals slower recharge, need more voltage to compensate and speed up recharge,

(A battery) singuar. Implying a finite capacity.

(Fastest Time) Stopwatch. Another singular parameter.

(Generator) assuming an implication that run-time enters the picturr for too many reasons to list.

Niner has it right. Singular fixed absorbsion voltage charging is so much faster, there is no competition. No matter how fixed voltage charging is accomplished it recharges a lead acid battery so much faster, it renders the thought of alternative methods as being absurd. Twomethods of monitoring - terminate the charge when all cells are bubbling lightly OR when amperes taper to a predetermined value.

For charging when shore power is not limited, Gyro Gearloose smart chargers have a shot as being an intelligent alternative. But not when time is a prime parameter to meet. Couple a spring wound timer calculated to a discovery of optimum recharge time window plus an ammeter and that is the OPTIMUM way to recharge a battery.

But 14.8 volts must be reached the instant the charger comes online. With a large battery bank this can entail hundreds of amperes.

The power source must have enough wattage to meet the energy needs to render constant 14.8 volts.

Yes, temperature correction enters the equation. 14.8 volts is not appropriate when camping at Point Barrow on Valentine's Day, nor Death Valley Junction on the 4th of July.

Unless you already have "big amp" conv/charger, the fastest.....and inconvenient way to charge is good jumper cables from TV alternator at fast idle.

gocamping14 wrote:
which method of charging a battery would be the fastest and most efficient when off the grid.

a. plugging the camper into a generator, running of course. (110v line)

b. plugging camper into the drive vehicle and running the engine.
(reg. 7 pin connection)

c. using a battery charger accessory on a generator running.

your thoughts, thanks............

ss

Answer depends on converter:

Magnetek 6300 UPGRADE to Progressive Dynamics (replace just the convrter part with a 4600) Then plug in

Parallex 7300 Use a smart charger

Any decent 3-stage charger/converter Plug in RV.