Camper battery quick charging

[Rustymax]

I have a double battery setup on my Lacrosse and I want to charge the batteries faster than what the converter or portable generator (special battery charging cable) is capable of doing. I have a “Vector” charger with digital smart control (DSC) for 3 stage settings, 15, 10, and 2 amp. The charger has a selection switch for wet, gel and AGM batteries. First I would like to know from the members is it your opinion that this is adequate sized charger or do I need a larger charging unit with more amps capacity?

Next, I thought I’d ask if plugging the charger directly into a 110 outlet, either on the portable generator or at the Campground power connection and then connecting the positive and negative alligator clamps to one of the dual batteries (batteries remaining connected to the trailer) is the best method to get a faster battery recharge? I want to be sure I don’t overload any camper circuits.

Before I forget, any recommendations for what model "Blue Sea" battery cut off switch is best for a double battery setup? I was thinking the 9003e,...suggestions.

Thanks

[Triguy]

My answers are below ...

Originally Posted by Rustymax

I have a double battery setup on my Lacrosse and I want to charge the batteries faster than what the converter or portable generator (special battery charging cable) is capable of doing. I have a “Vector” charger with digital smart control (DSC) for 3 stage settings, 15, 10, and 2 amp. The charger has a selection switch for wet, gel and AGM batteries. First I would like to know from the members is it your opinion that this is adequate sized charger or do I need a larger charging unit with more amps capacity?

This depends mostly on your batteries. The more the capacity; the higher the amps they can accept.

Awhile ago I wondered the same thing. I kept hearing a couple of different recommendations that were pretty close to these recommendations from Windsun.com

"Most flooded batteries should be charged at no more than the "C/8" rate for any sustained period. "C/8" is the battery capacity at the 20-hour rate divided by 8. For a 220 AH battery, this would equal 26 Amps."

Next, I thought I’d ask if plugging the charger directly into a 110 outlet, either on the portable generator or at the Campground power connection and then connecting the positive and negative alligator clamps to one of the dual batteries (batteries remaining connected to the trailer) is the best method to get a faster battery recharge? I want to be sure I don’t overload any camper circuits.

I also wondered this and have yet to find anything saying connected or disconnected. So, I just play it safe and disconnect my batteries (through a switch) when I charge them with my portable battery charger.

Before I forget, any recommendations for what model "Blue Sea" battery cut off switch is best for a double battery setup? I was thinking the 9003e,...suggestions.

For two 6-volts, the 9003-e or 6006-m, which is what I have, would work.

For two 12-volts, the 9001-e would work fine and provide more options (battery 1 or 2, both batteries or off).

Thanks

[LadyWindrider]

Sorry, I'm confused. If you are at a campground, with power available, and your camper is plugged in, Then most everything will run off the converter and the batteries will stay charged. Don't care how many batteries you have, up to a point. Your converter puts out usually 35 amps, some models 50 amps. You can get the model and stuff and find it online usually. Even if you have a generator, plug the camper in to that, and let the converter charge the batteries. An extra battery charger would be one less thing to take.

The one thing I do know, the faster you charge them, the more they boil off fluid, and the shorter their life becomes.

[Herk7769]

When I dry camp (I spend the winter in FL mostly dry camping), I never use the converter (or the goofy special cable) to charge my batteries.

The Converter takes DAYS to charge a depleted battery bank; because it "cares" about your batteries. It will start out at a high amperage charge rate and step it down as the batteries fill to avoid overheating, water "boiling", by the time the batteries are at 90% capacity, the charging current is less than an amp. (see the multi-stage charging section of your converter's manual; the battery charging graph voltage vs capacity); and the voltage as a percentage of capacity table)

The goofy cable is only good for charging the starting battery on the generator and not much else.

I switch off the batteries and plug in my ship-n-shore 25 amp battery charger and plug it in to the generator. It's "low" setting is 2 amps.
YOU MUST remove the battery caps when using this method as the batteries WILL off gas A LOT. They will also "use water" so you must carry a battery filler bulb; distilled (only) water; and a mirror to peek into the cells to make sure they are at the top of the ring. I also carry "Baking Soda" to make a wash to clean the battery top and box because there will be splashed electrolyte using the external charger.

[Rustymax]

Herk –
Thanks for the feedback; you confirmed some of my guesses. I think I’ll keep using my current Vector charger (15/10/2). It may take a litter longer to completely recharge the two 12V battery bank, but I’ll be on the safe side as to not shorten the battery life. I’ll also take your suggestion on the Blue Sea switch and purchased the 9001e model. Do I understand correctly that I can simply isolate the batteries from the trailer with the Blue Sea switch and recharge both batteries by connecting to only one battery (+/-) in the bank?
Windrider, you’re right about the need to charge batteries when using the campsite power connection. Duh -- another one of my brain farts, what was I thinking –wait I wasn’t thinking.
My main concern with the post is battery life when dry camping. I’m new to having power when camping, older popup and tents. This is my first travel trailer experience and I have only been out once so far. On the first outing, dry camping, I tried to use the trailer converter in conjunction with the portable generator, but like Herk said, “The Converter takes DAYS to charge a depleted battery bank”. I also found out that the “goofy cable” (special plug) on the portable generator also takes forever to recharge a battery bank. I’ll just plug the battery charger into one of the two 110 receptacles on the generator and recharge from there.

[ronhanson]

Many people rave about the vectors. They are good stand alone smart chargers, about the only thing better wouldve been the 40amp version. The vector has a good charging algorithm and will output what the batteries will take and no harm in keeping the converter in the loop, you'll get some added amps from it if needed. As mentioned, you will get some off gassing with the vector so just watch the water levels. This isn't a bad thing and does some good stirring the electrolyte unless you let the water level drop too much.

[Herk7769]

Originally Posted by Rustymax

Do I understand correctly that I can simply isolate the batteries from the trailer with the Blue Sea switch and recharge both batteries by connecting to only one battery (+/-) in the bank?

This totally depends on how you wire the switch and the batteries.

Let me work up some examples and I will edit this post and insert them when I am done tomorrow.

[kz08h5]

Take a look at this web site. It gives some pretty good info on batteries. It's for solar designs, but battery charging is battery charging.

The 12volt Side of Life (Part 1)

Another site that basically has the same info is

RV SOLAR QUICK ANSWER ? « HandyBob's Blog

I know about the converter not charging very fast. I thought I was going to freeze in Montana due to a discharged battery. I hooked the trailer to the generator and ran for about 3 hours. TT status palnel said full charge so I went fishing. Bad move. I now have a Schumaker charger that works well. But the battery did not survive the total discharges. I have learned my lesson.