Battery Charger

[MattM]

I am adding 2 additional 6 volt Trojans for a total of 4 batteries for the coach since I am tired of buying batteries every year. Dry camping for a few weeks puts a strain on the 12 volts and the number of cycles shorten's the life of the battery. Now the question is: does anyone know what size, as in how many amps, is the factory installed battery charger, ie "converter" . Also thinking about additional solar panels to the lonely one on the roof. The recommended charger rating is: total amps of solar array divided by 5, so a 460 amp-hour array (4 panels) would need a 90 amp charger.

[Iggy]

Originally Posted by MattM

Now the question is: does anyone know what size, as in how many amps, is the factory installed battery charger, ie "converter" .

Also thinking about additional solar panels to the lonely one on the roof. The recommended charger rating is: total amps of solar array divided by 5, so a 460 amp-hour array (4 panels) would need a 90 amp charger.

Answer #1 : Mine says 70 AMP on the label. (See Picture)

Answer #2: I thought solar panels were rated in watts at 12v dc?
So if you want 90 amps you will need 1080 total watts of power at 12 Volts DC to produce 90 amps at 12 volts DC.

[MattM]

Thnx Iggy. The formula came out of FMCA magazine

[DennyH]

Go to http://handybobsolar.wordpress.com

Priceless!!!

[Cornelius]

^ Agree.

Handy Bob is an excellent resource for learning about RV solar.

[MattM]

Well, I had a fabricating shop build a new battery tray and installed in under the steps for a total of $250. Tight fit but workable. Then I used welder's cable, 2 gauge, since it is more flexible, and had my rv repair tech install that. Cable and terminals $80 plus 2 hrs labor at $85 per hr for $170 total. Bought 2 new Trojans T-105 for $260 and 2 more Trojans to replace the 12 volt Deka's. They pro-rated the cost at $50. So total cost to upgrade to 4 six-volt Trojans: $550

So, next step installing an inverter. But should I get an inverter/converter and replace the factory converter?

[Witch Doctor]

Originally Posted by MattM

Well, I had a fabricating shop build a new battery tray and installed in under the steps for a total of $250. Tight fit but workable. Then I used welder's cable, 2 gauge, since it is more flexible, and had my rv repair tech install that. Cable and terminals $80 plus 2 hrs labor at $85 per hr for $170 total. Bought 2 new Trojans T-105 for $260 and 2 more Trojans to replace the 12 volt Deka's. They pro-rated the cost at $50. So total cost to upgrade to 4 six-volt Trojans: $550

So, next step installing an inverter. But should I get an inverter/converter and replace the factory converter?

most chargers on the inverter are 4 stage. If you are only going to get a 3 stage built into the inverter then I say no, If it comes with a true 4 stage then yes. Just my way of thinking.....

[Iggy]

Originally Posted by MattM

Well, I had a fabricating shop build a new battery tray and installed in under the steps for a total of $250. Tight fit but workable. Then I used welder's cable, 2 gauge, since it is more flexible, and had my rv repair tech install that. Cable and terminals $80 plus 2 hrs labor at $85 per hr for $170 total. Bought 2 new Trojans T-105 for $260 and 2 more Trojans to replace the 12 volt Deka's. They pro-rated the cost at $50. So total cost to upgrade to 4 six-volt Trojans: $550

So, next step installing an inverter. But should I get an inverter/converter and replace the factory converter?

It would be great if you showed us your MOD with a few pictures if you can.
Thx

[camaraderie]

Matt...suggest that with around 450amps of wet cells...your bulk charge acceptance rate is gonna be around 90 amps so if you get a combo with inverter...make sure the charging section is at least that big or a bit more to insure the fastest recharge when boondocking. Some chargers offer the 4th stage (periodic equalization) as a part of the charging process. Others make EQ a manual choice on your part. Others don't offer it at all...and should be avoided.

As to solar ... they need a controller..not a charger which is a completely separate issue. The batteries are the limiting factor for solar systems as well...since any system which put out more than 90amps at full output would be useless to your batts just like a larger charger would be. Unlikely on an RV!

You're likely looking at around 20-25 amps at full sunlight out of 400watts of panels so no worries about overcharging your new batts with a good Mppt controller. That would give you 100-120 amp hours back in to them on a typical day.

[Cornelius]

One problem I encountered when I needed to replace my defective converter/charger is that Forest River installed it in the last rear compartment with the 50 amp cord. That's about 20 feet from the battery location under the steps. The factory converter/charger was a 65 amp, 13.6 volt single stage Chinese model. I replaced it with an 80 amp Progressive Dynamics 4 stage model that is made in USA. Unfortunately, it is still in the rear compartment 20 feet from the batteries. It is best to have the charger as close as possible (but never in the same compartment) to the batteries to minimize line loss voltage.

When I added solar panels a few weeks ago, I installed the solar charge controller in the cargo compartment immediately adjacent to batteries under the steps. The cables are only about 2 or 3 feet long from the solar controller to the batteries.

[Iggy]

Originally Posted by Cornelius

One problem I encountered when I needed to replace my defective converter/charger is that Forest River installed it in the last rear compartment with the 50 amp cord. That's about 20 feet from the battery location under the steps. The factory converter/charger was a 65 amp, 13.6 volt single stage Chinese model. I replaced it with an 80 amp Progressive Dynamics 4 stage model that is made in USA. Unfortunately, it is still in the rear compartment 20 feet from the batteries. It is best to have the charger as close as possible (but never in the same compartment) to the batteries to minimize line loss voltage.

When I added solar panels a few weeks ago, I installed the solar charge controller in the cargo compartment immediately adjacent to batteries under the steps. The cables are only about 2 or 3 feet long from the solar controller to the batteries.

I tend to agree with you that the multi stage battery charger should and could be closer to the batteries. It can easily be replaced in mine as it is just plugged into an outlet and the two output DC leads. So far it does well and as long as the wire to the batteries are the proper size it shouldn't have much voltage loss. But it would be nice if it was in the compartment left of the steps in my 378TS.

[MattM]

thnx for the help. I only have 1 solar panel on roof; it's a Shell and I think it is putting out about 100 watts.

[Cornelius]

On my Georgetown, Forrest River used 6 gauge wire to connect the converter/charger in the rear compartment. It is acceptable, but slightly undersized for minimizing voltage drop to the batteries 20 feet away. I suspect the converter/charger was installed in the rear compartment because the fuse panel is located directly above it in the bedroom. The best choice would be to have the converter/charger, fuse panel, and batteries all within a few feet of each other.

[MattM]

I am trying to attach a couple photos of the battery tray under the steps. Let's see if they came thru.

[MattM]

Ok the battery pic is upside down, and the other one is a wood project I'm doing. sorry.

[Iggy]

Originally Posted by MattM

Ok the battery pic is upside down, and the other one is a wood project I'm doing. sorry.

That's why the liquid in the batteries keep leaking.
They are upside down.

[MattM]

First I had a hard time trying to figure out how to post the photos, now you have me curious as how to turn them around. Thnx