WEIGHT OF SOLAR EQUIPMENT

[artfuldodger]

We want to add a solar system to our 3605 2008 Monty and i'm concerned about the increased weight. The 4 6 volt batts. will be about 400# and the 4 panels will be about 150#. Of course that is minus the weight of the existing batts. The inverter is not heavy at about 12 #. If I go to G rated tires will I need new rims and also, what about those 7000# axles? I know lots of people in lots of brand 5rs have installed solar but how much upgrading is really necessary to remain safe?

[DQDick]

You'll have to weigh yourself to know for sure about tires, etc. As a 2008 you will most likely need new wheels if you go that route as I believe the 110# wheels didn't show up till late 2009 or early 2010. We weigh fine, even with Smart Weigh checking each tire, and we have seven panels, 6 6v AGM batteries and a 4000 watt inverter, we full time and have a lot of junk. So the basic answer is you need to know your weight, but you need to know that anyway.

[WaltBennett]

I put in four T-105s and they weigh 62 lbs each (according to Trojan). The four 100 watt panels I put on the roof, with wiring & solar charger, probably add another 140 lbs. I did get a much larger inverter than you're planning (4kw) and it weighs 70 lbs all by itself. We've still got the stock rims (but LT tires) and haven't had any issues with over 20k miles. Unless you're planning on over grossing the trailer, I don't think you need G rated tires

[artfuldodger]

I am planning on 4 trojan T125's which are over 100# each and 4 150 watt panels on the roof with an inverter of 2000 to 2200 watts. Maybe I could scale down the batts to t105's. we want to boondock in the southwest for 3 to 4 months and be able to run our coffeemaker, a hairdryer, a toaster, and the microwave, and of course the tv and a dvd player for a few hours at night. will the t105,s give me enough capacity for our usage?

[Bigboomer]

quote:Originally posted by artfuldodger

I am planning on 4 trojan T125's which are over 100# each and 4 150 watt panels on the roof with an inverter of 2000 to 2200 watts. Maybe I could scale down the batts to t105's. we want to boondock in the southwest for 3 to 4 months and be able to run our coffeemaker, a hairdryer, a toaster, and the microwave, and of course the tv and a dvd player for a few hours at night. will the t105,s give me enough capacity for our usage?

The 4 T-105's will give you 225 usable amp hours. For what you want to run you will need to manage your usage wisely. I suggest you add a Trimetric meter with a 500 amp shunt to monitor all your usage.

I will give you an example, if we use our 900 watt microwave (1400 watt in convection) for 1 minute it uses 3 amp hours.

Watching our TV for 3 to 4 hours a night will use around 15 to 20 amp hours.

If you are looking to use a toaster oven and coffee maker you will probably use 50 amp hours in 30 minutes.

I suggest you look to use heavy use items early in the morning as the sun hits the panels (if you tilt them) otherwise you are going to have to run a generator to freshen up the batteries more often than not.

You want to make sure you get the batteries back to at least 90% every day and at least 100% a couple of times a week.

With the Trimetric meter you will learn quick what each appliance uses and how to manage them.

[WaltBennett]

Got to disagree on your take Bigboomer. Here's the data sheet on the 105: http://www.trojanbattery.com/pdf/dat...ata_Sheets.pdf There's 185 Ah at a 5 hour rate (250 @ 100 hr.) and you can double that for four in 12v configuration. At 75 amp draw, one will last 115 minutes and that means 230 minutes for four in a 12v configuration.

I've used ours many times dry camping, with a table fan running overnight, microwaving some popcorn, watching a movie or TV on the 40", some lights & etc. By morning the Trimetric usually reads between 75 and 85%m and the batteries will be charged back up by 5PM with even partly cloudy days.

I've measured current draw on all our appliances by meter, including the AC. After the AC, the worst items are a coffee maker, toaster, the ref. on electric (that's a heater element), then the microwave, our large TV and the rest are all relatively low drains.

I completely agree with you about having a Trimetric, but also think an inexpensive watt meter is helpful. It's surprising the amount of current some things will draw or not draw, and if they are plug in, this is the easiest way to measure them.

Almost forgot - instead of climbing up & down to adjust tilt, PLUS not knowing what orientation we'd be in at a given CG, I opted to just fix the panels on either side of the center line so they'd have water drainage by the slope of the roof. Haven't had any problems at all with this setup and don't even need to clean them but once in a while.

[Bigboomer]

Walt,

Actually when figuring the battery storage capacity you use the 20 hour numbers which are 225 amps. With 4 battery's wired in a series/ parallel configuration you get 2 sets of 12 volt at 225 amps each or 450 amps total at 12v.

With wet cell or AGM batteries you never want to get below a 50 percent use of the total capacity or in this instance 225 amps of the 450.

The more you get to or use the batteries to 50 percent the shorter the life span of the batteries.

This is common practice for these types of configurations.

We measure how many amp hours we use not how many minutes we use something.

Give you an example:

Last night when the sun went down the batteries were fully charged. Through out the day our residential frig and 7 cu freezer are running drawing on the system. We have 6 - 305amp 6 volt AGM'S giving us 915 amp hours with 457 usable.
We used the microwave at 6:30 pm for 6 minutes and registered 18 amp hours used for that time frame on the Trimetric. We then proceed to watch TV for 3 hours. With the fantastic fans and tv running until 10 pm and the frig and freezer running we used another 50 amp hours. When we went to bed the usage was at 75 amps used of the 457. On average the frig and freezer use 10 amps/ hour. By 8 am today when the sun had just crested over the hills in AZ the meter read 175 amps used which is what we expect. When I check the batteries by percentage on the Trimetric is reads out at 80 percent which is correct based on the math.

By sunset today we will be back to fully charge and the cycle begins again.

[Mudchief]

You need to have your unit weighed then you will know how much you have to work with. We added IS and disk brakes to our unit and when Mor/ryde weighed our unit we were 13,756 on those 2 7K axles and we were not loaded heavy. They put the 8K axles on.

[7.3Ford]

Les (BigBoomer), is right on the money. You don't want to go below 50% on the battery.

I put a post out there today on my Lithium battery project.