Battery maintenance system: Solar & 120v

Electrical issues, both 12 volt and 120 volt
farnorth
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Re: Battery maintenance system: Solar & 120v

Post by farnorth »

Hello to Kentuckian and Skater! Thanks guys for your advice !!

As I will seldom use shore power or generator except for Microwave and occasional power tool use, I will monitor voltage with Trimetric 2025 when I use them and retain
Magnetek for emergency use. Kentuckian, there is a small box all sealed up near the AC. I assume this is where you hook up the solar panel, and it feeds power to the area
near the Magnetek for hook up to house Batt. ?
Again thank you both for your advice ! This is our third Motor home and the best one, We love it and only camp remote. Bob and Kate Gauden (farnorth)
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Kentuckian
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Re: Battery maintenance system: Solar & 120v

Post by Kentuckian »

Bob,

On my '93, I removed that cover finding the positive and negative wires that Airstream installed for connecting a solar panel. Those wires route to the inside of the Magnetek converter where they terminate with wire caps.

Before I did anything, I used my test meter to confirm that I was dealing with the correct set of wires running from the roof to the Magnetek converter. I eliminated the roof cover, connected my solar panel using solar panel style all weather connectors and just used flexible caulk around where the wires pass through the roof. I pulled the wires out of the Magnetek chassis and connected them to my solar controller.
1993 Airstream B190
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Kentuckian
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Re: Battery maintenance system: Solar & 120v

Post by Kentuckian »

The stock Motorcraft BH-50 house battery finally died this winter. Earlier in this thread, I had talked about planning to move towards multiple batteries in the generator bay. However, having lived with our solar battery maintenance system for a while now, I do not feel the need for multiple house batteries just yet.

Rather than replace the factory battery with another BH-50 format battery, I did decide to look for the largest deep cycle battery that I could fit in the factory location under the hood of our 1993 B190. Based on dimensions and capacity, I chose the Trojan SCS200. (Note: The SCS200 will not fit in the factory space without modifications!)

To make this larger battery fit, I made the following modifications:
(1) Ground off a plastic guide pin on the AC evaporator housing to prevent it from rubbing against the SCS200.
(2) Modified the FORD E350 house battery tray as follows...
a. Redrilled the mounting holes to shift the tray towards the firewall about ¾”
b. Added spacers under the tray to raise the tray ½” to clear a tray mounting bracket.
c. Modified the portion of the tray on the side facing the front bumper to allow the tray to accommodate the extra width of the SCS200.

The capacity of the B190 factory battery and the larger Trojan SCS200 that I installed follow.
- Motorcraft BH-50, 85 minute Reserve Capacity at 25 amps
- Trojan SCS200, 200 minute Reserve Capacity at 25 amps

The result is a 235% increase in battery capacity.

The SCS200 will fit. However, there is definitely no room to spare. This is a doable but tricky modification. If you don't want to make the modification for a larger battery, it appears that the Interstate Batteries C50-XHD is a drop on replacement for the Motorcraft BH-50 and the Interstate is rated at 108 minute Reserve Capacity at 25 amps.

Here’s a photo of the SCS200 installed. The numerous wires are for the Tri-Metric TM2025 RV battery meter and Morningstar solar battery charge controller.
Attachments
Trojan SCS200 installed in place of Airstream Factory battery
Trojan SCS200 installed in place of Airstream Factory battery
Trojan SCS200.jpg (28.96 KiB) Viewed 11725 times
1993 Airstream B190
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Kentuckian
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Re: Battery maintenance system: Solar & 120v

Post by Kentuckian »

We’ve been using this system for four year now. For those that are considering doing something similar, I thought I would pass along my thoughts.

We find that the small capacity Solar system that we installed is enough to power our lighting, run the water pump, power the two ceiling fans, run a radio, and recharge our phones and laptops for about three or four days. We rarely use the house battery for anything other than this.

There are a couple of considerations that significantly affect our experience with our small solar system. (1) To keep the camper cooler, we usually park under tree cover and that cuts the output of our roof top solar panel by half. So our one 100watt panel does not fully recharge the battery each day of being parked in shade. If we parked in the sun, the system does fully recharge the battery each day. (2) To avoid shortening the useful lifetime of the lead acid battery we don’t let the battery level drop below 50% of its rated capacity.

Our solar system presently serves our needs as is. However, I am considering a few changes that I will pass along in case they may be helpful as you consider your own plans.

Solar Panels :
I am considering moving from one 12v 100watt panel to two 12volt 180watt panels. Benefit is to increase our ability to get a full recharge of the house battery each day under partial sunlight conditions.

Battery capacity :
I’d like to double the battery capacity. What we have now, meets our present needs but with no safety margin. The excess battery capacity will help us get past a day or two of overcast skies and let us add the occasional use of small electric appliances.

Space heating :
We find the Airstream factory propane furnace to be pretty noisy and never use it. Also the blower is a huge current drain on the battery. So right now we don’t have a good way to heat the RV when we are not plugged in to the electrical grid. We do have a Mr. Buddy radiant heater. But the family is sensitive to the smell and it tends to create humidity in the cabin. I am looking into adding a small wall mounted propane indirect radiant heater (no blower) that vents to the outside world. The only battery load would be using the MaxAir ceiling fan in closed position to circulate the air inside the camper. Also at night we use an electric blanket. It only draws around an amp of current Vs ~10amps for an electric space heater.

Space cooling :
In our area and since we usually park in shade, we are usually fine just using our ceiling fan. Beyond the ceiling fan, we have no other way to cool the RV when off grid. We are usually fine without the AC, but it is a consideration if your weather is hotter than where we are.

Needing to run the roof top AC might be the only reason that we would consider going a generator route versus solar.

For our needs and where we usually camp, we are happy with the solar system.
Last edited by Kentuckian on Wed Nov 08, 2017 4:33 pm, edited 2 times in total.
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Choptop
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Re: Battery maintenance system: Solar & 120v

Post by Choptop »

Thank you, food for thought.
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skater
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Re: Battery maintenance system: Solar & 120v

Post by skater »

Kentuckian wrote:We find the Airstream factory propane furnace to be pretty noisy and never use it. Also the blower is a huge current drain on the battery.
This is pretty normal for RV furnaces, unfortunately - the issue with the B190 is that it's literally mounted inside, whereas, for example, on our trailer, it's actually mounted outside (still in the shell, but well buried behind furniture), so it's a lot less obtrusive.

As you noticed, one of the byproducts of the catalytic heaters is water, which adds to one of the big problems of camping in cold weather - the humidity inside the camper can be difficult to control. Also, you should open a window slightly, because they produce carbon monoxide and are unvented.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

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porkchop
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Re: Battery maintenance system: Solar & 120v

Post by porkchop »

is there room for two batteries under the couch ? We have one group 27 agm but we would like one more. Need help.
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Re: Battery maintenance system: Solar & 120v

Post by Kentuckian »

There should be room between the back of the couch drawer and the wall of the B190. You should be able to fit a couple of AGMs end to end. You should be able to take measurements by tilting the couch up and comparing those measurements with the batteries that you have in mind.

I don't have a generator and so I installed my three flooded batteries on a slide in the generator bay. My 2000 watt inverter and a Power Dynamics surge protector are mounted between the back of the drawer and the wall of the B190.
1993 Airstream B190
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