How long to recharge battery from shorepower?

rbpru wrote:
My question is, if I bought a small 700 watt generator or could plug into shore power for a short period of time, how long does it take my three stage WFCO charger to bring the battery back to full charge?

A WFCO probably never will as rarely does anyone report their WFCO capable of it's advertised 14.4 volt bulk charge rate. I'd be one - turned mine off permanently and replaced it with a stand alone charger that does do a 14.4 bulk charge.

How long? Well, how many batteries, what capacity, how depleted, etc, etc, etc? Until you provide those answers no one can really answer your question.

Don't waste your time with such a small solar system as just 45 watts ... useful perhaps for maintaining a single battery while the trailer is in storage but little else.

A low battery on WFCO to full? 24 to 48 hours. Initially strong but just a trickle voltage so the amps taper fast. Could still overload the 700w during initial charge. 700w is good for maybe 25 to 30 amps into the battery if you get the right converter or charger.

45w solar? Going to be high price per watt and not provide much except for storage. Need to be 200+ watts for better value and actually produce usable power.

"Full charge" is a long slow process. Using the small genny your talking about to charge will likely work, but it will get you enough to keep you going, but understand that a genny that small can not do anything else but run the charger. To put this in perspective for you, the size genny your looking at cannot run a normal household coffeemaker. Most of them are around 900 watts.

In greater detail, I have a three year old type 27 battery. It is rated about 100 amp-hours. Kind of standard issue with a 25 ft. TT.

In the past we have found it will last about 2 days, since we only use it for our LED lights, water pump and of course all the phantom loads. All our other needs can be met with the propane.

As I stated, the only time I needed a extra day or so, I just ran a set of jumper cables from the truck to the battery and let is charge for about 20 minutes. Crude but effective. :)

We thought we would try a bit more non-electric camping, to see if we really wanted to do it or to take advantage of a greater selection of camp grounds.

I would rather not use my truck to charge the battery it seem like a lot of over kill so I though a small generator or solar unit might do the job.

At this point whether my battery is at full charge or near full charge makes little difference, just so it has the juice to power the pump and LED lamps for a few days.

We spent years tent and canoe camping so our TT is basically a tin Tipi for convenient sleeping and cooking.

This is from Progressive Dynamics states in the brochures on how long it takes to charge a single deep cycle battery using a charger with a DC current output from 17A to 20A DC current.

"Progressive Dynamics ran this test on the amount of time it took a PD9155 (55-amp) converter/charger set to three different output voltages to recharge a 125 AH (Amp Hour) battery after it was fully discharged to 10.5-volts.
14.4-VOLTS (Boost Mode) – Returned the battery to 90% of full charge in approximately 3-hours. The battery reached full charge in approximately 11 hours.

13.6-VOLTS (Normal Mode) – Required 40-hours to return the battery to 90% of full charge and 78-hours to reach full charge.

13.2-VOLTS (Storage Mode) – Required 60-hours to return the battery to 90% of full charge and 100-hours to reach full charge."

This is based on having 17-20AMPS DC current available for each battery in your battery bank... NOTE That Progressive Dynamics doesn't even list using DC Charge Voltages around the 12.0VC range as this would take alot more than 100 hours to achieve a 90% or 100% charge state.

Roy Ken

3 year old batteries can fail. If not, I would consider a second battery.
Brian

Sounds like a second battery might be your best solution. That doubles your time without the need for any heroics. You could wire them both in to your system or just swap them when necessary. Otherwise, I would look at a generator. Certainly, you won't be able to run the genny for 30 hours to fully top off a battery, but if you run it for 3 or 4 hours with a battery charger hooked up that is dropping 10 or 12 amps into the battery, you will get enough charge to keep it going quite a bit longer. Also, with the genny running, it is a good time to use the power for those other things, like a pot of coffee or maybe a couple hours of TV or maybe run the A/C and cool down the camper for the evening. That would be a way to really open up some other camping situations.
Of course, you need to get a generator big enough for whatever you plan on running.
I have a Boliy inverter generator that is rated at 3000W continuous. That is enough to run the A/C, brew a pot of coffee all while watching Jerry Springer with power to spare for the battery charger.

I recommend two batteries minimum for off-grid camping. Might be all you need.

Then you need to decide if you want to replace the converter and get a generator. Need to maintain it, gas it, and listen to it.

Or go solar if you get any sun. I would almost always recommend solar first.

We have two batteries and a 2K honda gennie. Can use gennie to charge batteries every two days for a couple hours and we are good. Water fill.up issues before power. We camp similar to you in using it like fancy tent when off power.

I have never dry camped for an extended period. But I found a nice park about 30 miles away that only charges $5 a night and I might go park for a few days to a week. It is right on a river and is very quiet and peaceful. I have my trailer battery and I could bring along the trolling motor battery as well. It is in a Minn Kota Power Center case which makes that easy. But, I will bring the genny as well. Tough to go without some coffee and maybe some TV and A/C.