Planning Electrical Mods

[StrongJava]

After closing on our last house (Yay!), DW and I have decided to keep our 2008 Bighorn rather than purchasing new. It boiled down to floor plans.

We've now decided to start making some upgrades. A big one I'm starting is to make mods to the electrical system to increase our off-the-grid opportunities.

I've got a couple of portable generators ordered that I can slap into parallel for those times we need 110V/30A, and to recharge things.

The two steps I'm planning now involve designing and installing a battery bank to supplement/replace the current single coach battery, and swapping out lights/fixtures with LEDs. My goal is to have this project done by mid-January so we can hang out in the Quartzite, AZ, area for a couple of weeks. Longer term I'll look into solar panels.

Some important considerations:

1. Overall system weight. I have an auxiliary fuel tank in the truck, and I carry my tools behind the hitch. When the aux tank is full, my truck weight is pushing the limit (especially on the front axle). As I don't think it is wise to tell DW to lose weight (not that she needs to, mind you), I want to design a system that minimizes the weight impact since I figured this would be installed in the 5er's front compartment. I'm also considering beefing up or adding to my rear bike rack so could carry the generators back there while traveling, if necessary. I'm leading towards 12V batteries instead of 6V because I understand they have less housing weight and it would require less cabling.
2. Moderate power capacity. I'm calling it moderate. We don't need to run a TV, or a residential refrigerator. However, it is important to be able to run the computer/networking center for periods of time. This draws about 275W, although I could shed some (like one of my two monitors) of the load. The next highest load is probably our Dometic DM2862 refrigerator that we'd probably leave in 12V/gas mode, but maybe I should consider having the option of powering it off an inverter too? Beyond the furnace running at night, we'd like to have the ability to run the microwave/convection oven a couple of times a day. I understand each LED bulb should be about 1.5-2W?
3. Simplicity. Well, this is really a balancing act with the next two factors, but, in keeping it simple, is it a valid assumption that a single inverter tapped into a single battery bank is better than a couple of special purpose banks/inverters? Other things I should be looking at to keep it simple? If so, has anyone built a system that utilizes the existing battery compartment (I suspect it is too small)
4. Monitoring. I like data, and the ability to monitor performance.
5. Expandability. Primarily in terms of adding the ability to connect solar panels in the future.

Clearly I'm willing to engineer this but haven't done a project like this before. Are there other considerations I should have on my list? Money is always important, but it is not a limiting factor for this. I'm willing to do the labor in exchange for buying quality components.

I'm interested in hearing fellow Heartlander's experiences with designing and installing systems like this. Or links to projects you like. I'm already Googling but recognize that discussion often better than simply reading a blog.

Cheers, Tim

 

[Bogie]

HI Tim,

I can't address all your questions, but I do have some thoughts for you.

Regarding single vs. separate systems. I think you would only need one system unless you consider certain items you want to power as critical and must remain unaffected by the status of the other system. The other up side to having two systems is it would give you some redundancy should one fail for some reason. On the other hand, two systems would add additional weight, thereby affecting your concern about current weight limits.

Regarding monitoring, like you, I like to monitor the condition of my batteries. I use a Xantrex Link Light to monitor them. Check out my mod link in my signature for more info on this.

Regarding later adding solar....While I am no expert in this arena, I think you will find that this can be simple or rather complex. The complexity depending on the type of system you desire. Some systems require more equipment space than others. In a very simple system, you would only need enough space for a charge controller between the solar batteries and the battery bank.

I added the capability to use solar on my Sundance last summer. I only use it when boon docking to keep charging the batteries when I am not running my generator. I only have a small charge controller in the front compartment that does not take much room.

You may have considered this already, but you need to give some considerations as to weather you want to put in a transfer switch for when you go on generator power. I opted not to put one in my setup. I manually plug the Sundance power cord into the inverter because the only time I use it is when I am completely off the grid. One thing I always have to remember though is to disconnect the charge controller as it cannot be in the circuit when the inverter is running. I added an additional circuit breaker in the power panel to allow easy disconnection.

Hope this helps. I am sure others will have some thoughts for you as well.

 

[StrongJava]

Thank you for the reply. I can tell already I'm going to enjoy reading through your mods.

I have not wire diagramed this yet, and haven't really thought about a transfer switch vs a plug. Are you saying you run your shore-power line around to a female receptacle you installed after the inverter to then provide the power to your system?

Tim

HI Tim,

I can't address all your questions, but I do have some thoughts for you.

Regarding single vs. separate systems. I think you would only need one system unless you consider certain items you want to power as critical and must remain unaffected by the status of the other system. The other up side to having two systems is it would give you some redundancy should one fail for some reason. On the other hand, two systems would add additional weight, thereby affecting your concern about current weight limits.

Regarding monitoring, like you, I like to monitor the condition of my batteries. I use a Xantrex Link Light to monitor them. Check out my mod link in my signature for more info on this.

Regarding later adding solar....While I am no expert in this arena, I think you will find that this can be simple or rather complex. The complexity depending on the type of system you desire. Some systems require more equipment space than others. In a very simple system, you would only need enough space for a charge controller between the solar batteries and the battery bank.

I added the capability to use solar on my Sundance last summer. I only use it when boon docking to keep charging the batteries when I am not running my generator. I only have a small charge controller in the front compartment that does not take much room.

You may have considered this already, but you need to give some considerations as to weather you want to put in a transfer switch for when you go on generator power. I opted not to put one in my setup. I manually plug the Sundance power cord into the inverter because the only time I use it is when I am completely off the grid. One thing I always have to remember though is to disconnect the charge controller as it cannot be in the circuit when the inverter is running. I added an additional circuit breaker in the power panel to allow easy disconnection.

Hope this helps. I am sure others will have some thoughts for you as well.

 

[Bogie]

Are you saying you run your shore-power line around to a female receptacle you installed after the inverter to then provide the power to your system?

Tim

Yes, that's correct. I considered permanently hard wiring the connection, but decided pulling the shore power line around was satisfactory for my use. I can operate everything except the air conditioner with the inverter. It is important that you disconnect the charge controller form the AC when operating the invreter.

 

[StrongJava]

I'm working on a diagram of the my electrical system. I'm a pictures guy.

Also, looking the the 6V Trojan's vs the 12V, and I can see why people go with the 6V. Even though I need two to make one, and the weight is nearly double, the amp-hr performance is better than double. Am I missing something?

 

[danemayer]

I noticed in his signature that Brazos has a blog about his solar installation. Here's another resource.

 

[Oregon_Camper]

I'm working on a diagram of the my electrical system. I'm a pictures guy.

Also, looking the the 6V Trojan's vs the 12V, and I can see why people go with the 6V. Even though I need two to make one, and the weight is nearly double, the amp-hr performance is better than double. Am I missing something?

In my last 2 trailers, I used 2x 6v Trojan batteries. When I made the upgrade in our Bighorn, the math was no longer vastly different between 2x6v and 2x12v. I went with 2x12v (T-1275's) and LOVE them. Plenty of power....4-5 days without charging (no heater).

Knowing if one 6v fails, the entire system is dead vs one 12v dying and still able to use RV...was another reason to stick with 12v.

 

[StrongJava]

Any relation to you or is the last name just a coincidence?

I noticed in his signature that Brazos has a blog about his solar installation. Here's another resource.

 

[danemayer]

Any relation to you or is the last name just a coincidence?

No relation.

 

[StrongJava]

I think that is a good point especially if only running 1 pair of 6V. I think if I went with 6V, I'd have two sets.

I need to keep looking at the batter specs since I'm seeing vastly different numbers between 6V and the 12V. Nor am I sure I understand the difference between 5HR, 20HR, 100HR Amp-hr numbers.

In my last 2 trailers, I used 2x 6v Trojan batteries. When I made the upgrade in our Bighorn, the math was no longer vastly different between 2x6v and 2x12v. I went with 2x12v (T-1275's) and LOVE them. Plenty of power....4-5 days without charging (no heater).

Knowing if one 6v fails, the entire system is dead vs one 12v dying and still able to use RV...was another reason to stick with 12v.

 

[StrongJava]

I've been continuing my research and have put together quite a spreadsheet of battery options. Although I really liked the LiPo4 weights, I just am not really to plunge in that far.

But I've been bouncing back and forth on the flooded vs AGM. I need to gather more costs, but it seems that AGMs probably aren't for the the cost unless there is some reason flooded batteries aren't appropriate in the system (i.e., need to put them in living spaces).

One point I'm not sure I understand yet is that some claim AGM batteries can be discharged more deeply without affecting the life of the battery, compared to flooded. However, I'm not sure I see the data to support this. Manufacturers' data in many cases seems to show flooded have more cycles in their lives even at 80% Depth of Discharge.

Please share your experiences with AGMs vs flooded as it relates to deep cycling (which I assume I would do while boondocking, especially when I don't have solar yet).

Cheers, Tim

 

[StrongJava]

I've been trying to find a plastic storage bin that would work as a battery box containing four Trojan T-105-size batteries. I want to put these in the front storage compartment longitudinally aligned with the RV. This means the outer dimension of the box can't be more than 24-1/4 inches long while the inside length has to be nearly 21". I came real close with a Sterlite 65qt, but the inner width was just shy of what is needed.

Does anyone have a box of this size? I'm trying to avoid buying a $70 custom job.

Tim

 

[Bogie]

Tim,

I don't know if they have the size you want, but you can check out this web site.

I bought the one I use from them and installed it in the front compartment. You can see some pictures of this by checking out my mods including that one in my signature below.

 

[carl.swoyer]

I use 4 group 31 deka agm batteries. 1 220 watt solar panel with a morning star duo charge controller. The controller allows me to split the incoming charge to each battery bank. I installed the Onan 5500 Marquis LP genset. My dry camping runs off a Magnum ms2813 pure sine waves inverter to select circuits in the Rv. Occasionally I run the Onan to do a bulk charge on the house batteries and the dry camp batteries. It's nice having the Onan because you just push the genset start button and your running. While charging from the Onan I set the Magnum to 30 amp shore power. This allows me to sufficiently charge both banks of batteries without over tasking the Onan. ( The factory charger is 105 amps and the Magnum can dump a huge bulk charge as well.) The AGM battery charges alot faster than the wet cells.

Sent from my XT1254 using Tapatalk

 

[StrongJava]

Happy New Year, Joe-

Thanks for the reply. I'd been poking through your mods earlier, but didn't catch the bit about cutting a hole in the floor for your battery box. I can see where that would free up some space inside the front compartment, but do you in fact find yourself stacking stuff on top of the battery box when the lid is closed?

What did you use for straps to hold the box in place? Did you screw them to the floor too?

I saw that battery box at All Battery Sales and Service. It costs $75 plus over $40 for shipping. I was looking for something less expensive since I really didn't feel I needed marine grade. But with your other mod in mind, hmm...

Tim

Tim,

I don't know if they have the size you want, but you can check out this web site.

I bought the one I use from them and installed it in the front compartment. You can see some pictures of this by checking out my mods including that one in my signature below.

 

[StrongJava]

Hello Carl,

Do you have some first-hand experience or data that compares charging times of AGM vs flooded? I ask because as I was researching, I found data that suggests the improved DoD vs cycle life claimed by AGM advocates isn't what is being experienced in the field, nor do the claims appear to be supported by the spec sheets I read, especially when I figured in the cost differential. When I asked a guy a battery store, he admitted that most of their sales of AGM batteries were going to really cold weather solar apps or to machinery that operated in-doors. Other than those applications, the key advantage of AGM appears to be the lack of required maintenance. I don't mind putting my hands on them every month.

I found some FVP, Trojan-manufactured, 105s at a price I figured was not worth passing up. I'll pick them up in Las Vegas next week. The monitoring system and charger I ordered should let me work with either type of battery.

In any case, I'm still interested in adding data to my spreadsheet.

Thanks, and happy new year!

Tim

I use 4 group 31 deka agm batteries. 1 220 watt solar panel with a morning star duo charge controller. The controller allows me to split the incoming charge to each battery bank. I installed the Onan 5500 Marquis LP genset. My dry camping runs off a Magnum ms2813 pure sine waves inverter to select circuits in the Rv. Occasionally I run the Onan to do a bulk charge on the house batteries and the dry camp batteries. It's nice having the Onan because you just push the genset start button and your running. While charging from the Onan I set the Magnum to 30 amp shore power. This allows me to sufficiently charge both banks of batteries without over tasking the Onan. ( The factory charger is 105 amps and the Magnum can dump a huge bulk charge as well.) The AGM battery charges alot faster than the wet cells.

Sent from my XT1254 using Tapatalk

 

[carl.swoyer]

Personal experience with the Trojan and DEKA AGM. The DEKA charges faster. The Trojan required topping off the water. No battery acid mist . I dry camp in Key West Florida for 6 weeks at a time . DEKA AGMs are so sweet. Set em and forget em.

Sent from my XT1254 using Tapatalk

 

[StrongJava]

Re: Planning Electrical Mods--weights?

Good to know, Carl. Thanks.

Has anyone ever had issues with the amount of weight they put on the floor in the front compartment? I see Carl's Onan genset weighs about 280lbs. I've got my portable generators up there (110 lbs), a couple of storage bins (25lbs?), and will be adding about 260lbs of batteries. I've searched, but haven't found a weight rating for that floor.

Thoughts?

 

[Bogie]

Happy New Year, Joe-

Thanks for the reply. I'd been poking through your mods earlier, but didn't catch the bit about cutting a hole in the floor for your battery box. I can see where that would free up some space inside the front compartment, but do you in fact find yourself stacking stuff on top of the battery box when the lid is closed?

What did you use for straps to hold the box in place? Did you screw them to the floor too?

I saw that battery box at All Battery Sales and Service. It costs $75 plus over $40 for shipping. I was looking for something less expensive since I really didn't feel I needed marine grade. But with your other mod in mind, hmm...

Tim

Happy New Year Tim.

I made the supports from 3/16 thick aluminum bar. They are bolted to the pan and then the new battery case sits in that framework without any additional attachment. The battery box does have a lip molded into it near the top. I made the brackets so that the lip just meets the top of the bracket. That adds some extra support. I haven't had any problems so far.

Yes, I do stack some things on top of the battery cover, but only items that are light in weight. It seems to work for me just fine.

 

[StrongJava]

My box would be bigger thus requiring more of the floor to be cut out (~22x15 inches) and my weight (assuming 15lbs for the box and cabling) is roughly 265lbs. I'm thinking if I added more strips I should be fine, but I'd rather find something data-driven that supports my WAG.

Happy New Year Tim.

I made the supports from 3/16 thick aluminum bar. They are bolted to the pan and then the new battery case sits in that framework without any additional attachment. The battery box does have a lip molded into it near the top. I made the brackets so that the lip just meets the top of the bracket. That adds some extra support. I haven't had any problems so far.

Yes, I do stack some things on top of the battery cover, but only items that are light in weight. It seems to work for me just fine.