Do I really need a converter?

[wrdaigle]

Hi all,

I am in the process of upgrading the electrical system in my 1989 Scamp 19. I just purchased two 6V deep cycles that I am in the process of installing in the bottom of the closet. No, they are not sealed...just regular FLA. But don't worry, I'm going to seal off the the base of the closet and provide adequate ventilation. My main motivation for moving the batteries inside is so I can keep them warm on cold winter nights. I have already discovered the the challenges associated with running the furnace all night when the batteries are sitting outside in sub-0F temperatures. I plan to install an access panel that I can remove on cold winter nights and keep the batteries warm; there is no danger in doing this since batteries only off-gas during the charging phase.

As part of the upgrade, I'm going to move the key electronics into the upper, unsealed portion of the closet. At the very least, I would like to upgrade the distribution panel so it's more accessible and expandable. My question is...is it worth incorporating the existing converter. The converter is the original (as far as I can tell) and the incorporated battery charger is basically just a small trickle charger. This would be fine if I was often hooked up to shore power, but I am not. My primary charging is soon to be solar ( I plan to hard-mount a 150w panel on the roof and get a seperate ~80-100w portable panel for boondocking). Since I'm rarely hooked up to shore power, I don't really have need for a trickle charger. Additionally, I do carry a Honda EU2000i which I use for power the air conditioner (mostly for keeping the dogs cool when we are out playing). I would like to incorporate a larger charger so I could quick charge the batteries with the generator if necessary. Some of the newer converters come with larger chargers that seem like they might work well; this one from progressive dynamics seems like it might meet my needs. My concern is...would I be able to turn off the charger when I want to run the AC on the generator. I don't think the Honda would start up the AC unit if was also putting a lot of current into the batteries. If not, would I be better off just scrapping the converter and getting a distribution panel and a separate stand-alone charger?

[sarahspins]

I didn't put one in my 13' scamp (it never had one as far as I can tell) and I don't plan to, but I do have a 100w solar panel to keep my battery charged. So far I've had no problems powering led lights, charging my phone, and running my 12V engel fridge. I do plan on switching over to dual 6V AGM batteries in the near future so I have more reserve when there isn't as much sun (due to weather or shaded campsites), but I'm not worried about charging my batteries from shore power or my generator.

[Borrego Dave]

Hi Bill and wecome to FGRV. As far as generators go, I have two all Honda. A 2000 that I use with the trailer and a 3500 I used for power outages at home. Generators as far as I know don't put out a whole lot of 12 volt power for your batteries. Running the tugs motor will put out a whole lot of amps for charging over a genny in thirty minutes. I use a solar panel to keep the trailers battery up and the 2000 for coffee and the micro wave, about 15 minutes a day. We are not in the trailer much other than cleaning up and sleeping so we don't use much battery power. I've only had one battery in any of my RV's in thirty years and only had full hook ups for one week at Lake Powel. Just depends on how you camp. Others will be here to give you info too.

[wrdaigle]

Thanks for the welcome message. I've been lingering for while, but I guess this is the first time I posted. I really this forum.

In general, I don't use a lot of battery power. I did, however just get an edgestar chest fridge, which will certainly use the lion's share. It looks like it's going to use about 30-40 Amp-hours per day, so I should be able to get by for at least a couple of days with 200AH capacity.

Generators as far as I know don't put out a whole lot of 12 volt power for your batteries. Running the tugs motor will put out a whole lot of amps for charging over a genny in thirty minutes.

I definitely disagree that you can charge a battery faster with a alternator than a generator. The on-board battery charger is the problem, not the generator. I live off-grid and I use the Honda 2000 as back-up power for my house. It's a battery charging machine when paired with the right charger.

I am definitely leaning towards leaving towards foregoing the converter and saving my pennies for a good battery charger that I can run independently from the AC. Any strong converter opinions out there?

[MCDenny]

Isn't a battery charger and a converter almost the same thing? 120vac to charger --> approx 13.8 v to battery --> 12v to trailer up to amp capacity of charger.

Of course you can turn off charger when running A/C from the generator.

With 100w of solar panel and sunlight you will (almost) never need the charger.

We have 100w solar, 220 ah battery bank, the usual lights, phone chargers, etc and a 12v 4 cu-ft compressor fridge. Turned off the charger last March, battery has never been below 100% in the afternoon. This obviously wouldn't work so well in a cloudy rainy climate or deep shade.


Denny Wolfe
Wanderingourway.wordpress.com

[MCDenny]

Originally Posted by wrdaigle

I definitely disagree that you can charge a battery faster with a alternator than a generator. The on-board battery charger is the problem, not the generator. I live off-grid and I use the Honda 2000 as back-up power for my house. It's a battery charging machine when paired with the right charger.

I suspect he meant (and he's right) the 12v output from the EU2000 would not charge your battery much if at all. Plugging in a charger to the 120vac output works great.

On a related note, even though my car has an 80 amp alternator, it doesn't seem to charger the trailer battery very fast. I imagine the slight voltage drop through 25' of wire and the seven way connector is the culprit.


Denny Wolfe
Wanderingourway.wordpress.com

[Night Sailor]

I have been tempted to pull out my converter and charger and sell it. It is a 35A charger but it is four stage and I don't want the equalization stage. I will probably just swap out the charger.

My solar provides for all my needs so a converter is mostly useless too.

I used the charger to top off my batteries once but have used solar ever since.

I use the power distribution bus but would prefer a breaker panel or a Wago Din Rail distribution--they make these with blade type fuses.

My vote: dump the converter and get a good charger appropriate for your battery type. More solar is addictive too if you need a heroin rush of Volts and Amps.


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[Nate R]

I'l be doing the same, going convertor-less. Just an on board 120V charger/maintainer, and solar. Going to use a marine fuse block as my distribution. Don't see a reason you need the convertor if you already know your needs and how you use power!

[wrdaigle]

Thanks Denny,

Good to hear you've been getting by with a 100w solar panel. The general rule of thumb in the off-grid solar community is to shoot for 5-13% of the batteries capacity in charging current. For instance, if you have 225AH of battery capacity, you should shoot for 11.25-29.25 in charging Amps to ensure long battery life. A 100 watt panel is only good for about 8 amps, so you're certainly on the low end. That's not to say it can't be done. Lots of people do it, but batteries will be more likely to get sulfate earlier if they are under charged. Situations certainly vary. On my home system, I run closer to the 5% side, but I live in Montana where we get lots of sun and very few cloudy days.

As far as converters go. They are not really the same thing as chargers. I think their main purpose is to convert 120v AC to 12v DC when shore power (or generator) is in use so the 12v appliance can run directly off the shore power instead of the battery. Some converters have an integrated battery charger, but not all, and not all chargers are created equally. The battery charger in my current converter maxes out at about 4A. It would take a LOT of generator time to charge the battery at that rate. A good 3-phase battery charger can push 60A or more during the bulk phase.

[stevebaz]

You post that you want to upgrade the distribution center and whether or not to include the old charger.
Don't include the old outdated dumb charger. Since you are planning to change out the panel and relocate I would change it to a modern panel with a smart charger. You will in some cases have to wire in a switch to kill the charger when you don't want to use it. That's better than pulling a fuse to kill it when not needed. By changing the out to a more modern complete system at lease you wont have the old battery killer and you wont have to carry and store a separate charger. The price differential is not really that far apart.

[honda03842]

We have Solar panels but kept our converter, a small Progressive Dynamics. Our motorhome had a PDI convertor as well and our batteries were original to the vehicle when we sold it, I believe 15 years old. I attributed this to the desulphation cycle on the PDI.

We spend 4 months home during the typical summer and never shut off the PDI even when not using the trailer, that also goes for the fridge. We think most of the trailer equipment is better continuously powered and the reality is that they do not draw much power when sitting.

When we first got our trailer we left the motor home in the yard for 8 months, still under power. The batteries always seemed happy. Now this is not scientific, no doubly blind study, only no fridge or battery problems, just long life.

Also we left a power chord on the charger and could unplug it from it's outlet in seconds.

[MCDenny]

Bill,

The general rule of thumb in the off-grid solar community is to shoot for 5-13% of the batteries capacity... My battery manual 'recommends' 10% but my PWM solar controller puts out about 6 amps max, only about 2.5% The battery still gets to 100% each day as I don't use that many ah. I have a CC-CV power supply to equalize the batteries every once in awhile. Hoping for the best.

As far as converters go. They are not really the same thing as chargers. I think their main purpose is to convert 120v AC to 12v DC when shore power (or generator) is in use so the 12v appliance can run directly off the shore power instead of the battery... I guess I never understood why you would want a 12v power supply instead of a battery and charger. There are certainly times when you want at least light and aren't connected to shore power. If you've got a battery you have to have a charger anyway so why not have a decent one, say 20 or 30 amps, and make a converter redundant. The 12v loads can run off the charger output even if the battery is dead.

Are converters possibly a holdover from old times when travel trailers were much more simple and only had a few lights powered small battery recharged by the tow vehicle?

[wrdaigle]

Originally Posted by MCDenny

Are converters possibly a holdover from old times when travel trailers were much more simple and only had a few lights powered small battery recharged by the tow vehicle?

I don't think they are really a holdover. I think the majority of RV users are generally in an RV park where power available at all times. With a converter, they don't necessarily even need a battery. I would say that is their biggest benefit. Even if you're battery dies, you can still use 12v appliances. I'm not really that worried about my battery dying.

[wrdaigle]

Originally Posted by honda03842

We have Solar panels but kept our converter, a small Progressive Dynamics. Our motorhome had a PDI convertor as well and our batteries were original to the vehicle when we sold it, I believe 15 years old. I attributed this to the desulphation cycle on the PDI.

15 year old batteries! Nice. Sounds like you're doing something right.

[honda03842]

Bill, I never really thought much about it until I listened to others. I'm continuously amazed when I read about the AMG batteries when are Trojan 105s seemed to last forever.

We always carry distilled water for our batteries to top them off with the right stuff.

[wrdaigle]

Originally Posted by honda03842

Bill, I never really thought much about it until I listened to others. I'm continuously amazed when I read about the AMG batteries when are Trojan 105s seemed to last forever.

We always carry distilled water for our batteries to top them off with the right stuff.

I agree. Trojan SLA's are really hard to beat. When I moved into my house, there were 20 Trojan L16s (these have twice the capacity of T105s). This was a HUGE, poorly designed battery bank that was severely under charged for it's entire life. Despite that, they still lasted 8 year. I ended up replacing them with much smaller fork lift battery. It has about 1/4 the capacity of the previous bank, but is sized appropriately and therefore requires a lot less generator time. It works great and hopefully will continue to for the next 15 years.

I seriously considered getting AGMs for the scamp since I want to put them inside, but in the end I decided it was more economical to install SLAs in a sealed/ventilated compartment. I also like being able to monitor specific gravities. I ended up buying Costco batteries this time around. Even I only get a few years out of them, they will give me an opportunity to get the setup figured. Once I get everything dialed in, I won't have a problem spending the extra $$ on Trojans.

[RogerDat]

If the converter has a good charger as well as the ability to run 12 volt appliances from shore power that is a benefit.

If you add in a cut off switch to take the converter off of the shore power circuit if your running the AC I think you would have the best of both worlds.

It was not uncommon for some of the early campers with microwave and AC to have a switch that only let you run one at a time since both at once would tend to trip the breaker. AC off for a few minutes while using microwave then flip the switch back to AC.

If nothing else built in ability to charge batteries while not drawing off of them seems like it would be an advantage to having a converter. E.G few days of cold and inclement weather where the furnace has drawn down the batteries. Fire up generator plug in and you can run furnace while charging batteries without drawing power from the batteries you are trying to charge.

[wrdaigle]

One thing is for sure. I am going to scrap the existing converter. I'm going to ponder whether or not buy a new converter/charger combo or a distribution panel and separate charger. I think if wire in a switch for the charging portion, I suspect it might be cheaper and tidier to go the combo route. I'm still not convinced I need the converter portion, but if it comes along with a distribution panel and a good charger, I'm not against it either.

Thanks for all your thoughts and recommendations.

[Night Sailor]

I would like to remove the charger in my converter. It is a four stage 35 amp charger. I'll let it go cheap. It is new and only used once to bring a battery up to full charge. I have used it since. It is appropriate for a flooded battery or one that needs to be or tolerates equalization charges.

It's a progressive dynamics and a typical mod to replace constant current chargers. I paid $210 for it. It's yours for $100. I can get more details next week if you are interested. Send me a PM.

I want to swap it for a small 3 stage charger. There is a 10 amp marine charger I was thinking of using. Slower charging reduces heat and helps prolong the battery life. I don't expect my charger to be used except on rare intervals when it is in covered storage. My solar meets all my needs.


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[Jared J]

Originally Posted by MCDenny

Bill,

The general rule of thumb in the off-grid solar community is to shoot for 5-13% of the batteries capacity... My battery manual 'recommends' 10% but my PWM solar controller puts out about 6 amps max, only about 2.5% The battery still gets to 100% each day as I don't use that many ah. I have a CC-CV power supply to equalize the batteries every once in awhile. Hoping for the best.

As far as converters go. They are not really the same thing as chargers. I think their main purpose is to convert 120v AC to 12v DC when shore power (or generator) is in use so the 12v appliance can run directly off the shore power instead of the battery... I guess I never understood why you would want a 12v power supply instead of a battery and charger. There are certainly times when you want at least light and aren't connected to shore power. If you've got a battery you have to have a charger anyway so why not have a decent one, say 20 or 30 amps, and make a converter redundant. The 12v loads can run off the charger output even if the battery is dead.

Are converters possibly a holdover from old times when travel trailers were much more simple and only had a few lights powered small battery recharged by the tow vehicle?

How so? My converter has a 4 stage charging cycle, none of my three chargers do. Oh, and it puts out 45 amps max., along with being a clean fuse and breaker panel.

If you don't want one, fine. To say they're not really a charger, though?


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