Battery Bank Installation Location

[csommers4]

Hello, I have purchased two EG4 24v 5.12kwh batteries and in the process of deciding where to keep them in my 2019 351M. I will live full-time in this rig, and I "home base" out of MN during the summer/fall months and have been caught in below freezing temps with my last rig (sometimes reaching -10F). I know this model is insulated, however the compartment where the ONAN 5500 generator is not.

The operating parameters of these batteries are as follows:

Charging Range: 0 c ~ 45 c (32F to 113F)
Discharge Range -20 c ~ 55 c (-4F to 131F)
Storage Range -20 c ~ 55 c (-4F to 131F)

Putting them in the compartment with the generator seems like I would be over temp when it is running, especially in full-sun/summer mode where the A/C units are running and the generator is heavily used. Anyone else run into this issue and the solution? Venting with an auto-temp sensing exhaust fan? Different location?

Any advice would be appreciated.

Thank you

[howson]

csommers4

First--welcome to the forum. Please take a moment to fill out your signature line as mentioned in the Welcome Letter (linked off the home page).

Those batteries suggest they will power a robust inverter. If it will be an inverter/charger (like a Victron Multiplus or something similar) powered from those batteries the best practice is to locate the bank as close as possible to the inverter/charger to keep the wire run short. With a 24V system there's a bit more leeway with the wire length (since amperage is reduced) but it's still a consideration nonetheless.

A test is in order regarding the overtemp potential. What I'd do is put an instrument like an Elitech in the compartment and run the generator (preferably on a hot day). Then download the results to see what's happening in that compartment. As an example, check out https://gdrvowners.com/forum/interio...ight-insulator where I determined an RV Skylight Insulator was a bad idea (based on testing using an Elitech).

For undertemp, there's been suggestions in the past on this forum to use a critter-warming bulb, an old-fashioned incandescent, a heating blanket, and probably more I can't remember. Others will chime in on that issue, I'm sure. d2reid is our designated "cold weather camper" but I'm not sure he has had battery issues.

Please keep the forum up-to-date on your installation. I'm sure you'll have some lessons learned to share.

Again, welcome!

Howard

[acoleman43]

csommers4 I like Howards suggestion. If you keep them in the front compartment, I would suggest a battery warmer it you're worried about it.

Another good location is in the garage or under your bed (inside).

I installed a 24v system as well. One thing I did not consider is the starter for the generator is 12v. This forced me to carry one 12v battery just for the generator starter :(

Cummins does sell a 24v started for he Onan generator, but it's about $800....and is in the back of the generator (I would have to completely remove my generator to change it out).

What inverter are you planning to use? How are you planning to reduce voltage for your 12v system?

[csommers4]

csommers4



Those batteries suggest they will power a robust inverter. If it will be an inverter/charger (like a Victron Multiplus or something similar) powered from those batteries the best practice is to locate the bank as close as possible to the inverter/charger to keep the wire run short. With a 24V system there's a bit more leeway with the wire length (since amperage is reduced) but it's still a consideration nonetheless.


Again, welcome!

Howard

Thank you for your reply and welcome.

Yes there will be a Victron MultiPlus II 24v 2x120v output connected to the batteries and I was thinking either mounting on that back wall, or in the "basement" on the opposite side and I'd go through the barrier wall- no more than 3 feet of 2/0 wire.

I'll have 2 Victron Orion 24v-12v 70amp (for redundancy) to power the 12v system, including the generator start. In July I will order some solar panels to add to the mix, but for now I want the ability to plug into a 15amp circuit and have a functioning rig with A/C without running the generator 24/7 using the PowerAssist feature of this inverter. I had a Multiplus 12/3000./120 in my last rig and it worked perfectly doing this.

Hopefully I've addressed the signature issue?

[csommers4]

csommers4 I like Howards suggestion. If you keep them in the front compartment, I would suggest a battery warmer it you're worried about it.

Another good location is in the garage or under your bed (inside).

I installed a 24v system as well. One thing I did not consider is the starter for the generator is 12v. This forced me to carry one 12v battery just for the generator starter :(

Cummins does sell a 24v started for he Onan generator, but it's about $800....and is in the back of the generator (I would have to completely remove my generator to change it out).

What inverter are you planning to use? How are you planning to reduce voltage for your 12v system?

- I suppose the generator will need more than 70 amps to start... I am putting in two Orion 24v-12v converters to power the 12v system (two for redundancy) but was wondering about the genny. I'd need to buy a converter just for that starter battery.

Inverter is a Victron Multplus II 24v 2x120v output inverter charger. Got the Cerbo GX with it, will add some MPPT's in July for some panels on the roof, which I'm currently drawing up.

[d2reid]

[USER="17026"] Others will chime in on that issue, I'm sure. d2reid is our designated "cold weather camper" but I'm not sure he has had battery issues.

Howard

THanks for the mention howson , The main reason I stayed away from LIon batteries was because of the charging temp range. My old fashioned batteries are located in the same spot csommers4 depicts his. That bay is not heated in any way and very exposed. The skirting around the overhang helps protect it, but it still gets subfreezing cold. This abuse causes me to replace my batteries every 2-3 years.

If the 351's front bay is designed like mine you may be able to create room for the batteries in a heated area by removing the wall, then managing the wires. There is a lot of air space back there.

[acoleman43]

- I suppose the generator will need more than 70 amps to start... I am putting in two Orion 24v-12v converters to power the 12v system (two for redundancy) but was wondering about the genny. I'd need to buy a converter just for that starter battery.

Inverter is a Victron Multplus II 24v 2x120v output inverter charger. Got the Cerbo GX with it, will add some MPPT's in July for some panels on the roof, which I'm currently drawing up.

Sounds like a great system.

A few things I learned from my install:

-You, essentially, have two 12v systems: System1: main distribution panel, system 2: "always on" system (tongue jack/electric leveling, emergency brake, possibly co2/smoke detectors, etc). I have the 70a Orion DC-DC converter for my distribution panel. I also have a separate 25A for the "always on" system. These 2 systems have different "shut-off" switches for obvious reasons. You may have to run new wire from some of your current hardware to the new battery location.

-Onan generators recommend 450 cca battery to start. Trying to find a DC-DC converter or "Buck Booster" that had the capacity to start the generator was a massive cost. It was easier to just keep a "small" 12v "starter" battery for this. You may want to consider keeping a generator starter battery next to the generator in the front compartment. cable runs are shorter and you don't have to mess with converting 24v into 12v for it. To keep my 12v starter battery charged, I bought a VIctron Bluesmart IP22 charger which is plugged into the back of the main distribution panel with the wiring to the 12v battery. This was a simple solution that took advantage of the solar/inverter so I didn't have to come up with a complete separate system (however I do loose a little efficiency in the conversion from DC to AC then back to DC).
I installed the IP22 in a interior cabinet next to the distribution panel. Hasn't gotten in the way yet






-Oversizing wires/cables is better than under sizing. When sizing my wires/cables I used 2% voltage loss on everything...whether it needed it or not. I'd rather spend a little more up front, then to risk a fire that would destroy thousands of $$ of equipment/RV. If it was borderline between 2 sizes, I went with the larger size. Even with a 24v system I still have some 4/0 and 2/0 cable.

-Cerbo GX is more capable than I thought. I am making use of the programmable relays available with the Cerbo. I have 2 fan circuits that are connected to these relays. One runs cooling fans for the Cerbo and batteries, and the other for the Inverter and Solar Charge controllers. I have temp sensors in each area. Once the temp exceeds about 100 degrees the fans switch on. When the temp drops below 90 degrees the fans switch off. Below you can see the 2 "fan circuit" temperatures. Because they are both below 90, the fans are not running. IF you are interested in running heating pads or anything that you want a prgrammable relay to control, use the Cerbo. It works great. (You can even use it to automatically start your generator if the battery bank drops below a specified level).






-Spend the extra $ to get the Touch 70 over the Touch 50. The extra 2" makes a huge difference when your eyes get old. In the pic below you can see the visual difference vs the Touch 50.






-Spend the time to do it right. Planning and preparing and leaving enough time to trouble shoot, make necessary adjustments, and make sure things fit/work is well worth it in the long run.

About you batteries. When I did my install last year, I was waiting for Signature Solar to get your EG4 batteries in stock.. I think they are a tremendous value....better than SOK and many others IMO. However, due to supply chain issues, Signature Solar could not get all components for the battery......so They sold the cells (8 cells with welded terminal) they use. I jumped in it and bout 4 of these, then added Overkill BMS' to each "battery". So far they've been excellent. You should have no issues with them. Below are the "batteries" with the BMS'....these are the cells you have in your EG4's.





Please keep us posted on your build. Sounds excellent!

[acoleman43]

THanks for the mention howson , The main reason I stayed away from LIon batteries was because of the charging temp range. My old fashioned batteries are located in the same spot csommers4 depicts his. That bay is not heated in any way and very exposed. The skirting around the overhang helps protect it, but it still gets subfreezing cold. This abuse causes me to replace my batteries every 2-3 years.

If the 351's front bay is designed like mine you may be able to create room for the batteries in a heated area by removing the wall, then managing the wires. There is a lot of air space back there.

That's what I would attempt. Create a box for the batteries. Line with insulation and heating pads (if necessary), add a fan that can circulate air when hot.

This would save space in the garage for other things and the front compartment is a much easier space to access and maintain the equipment.

[csommers4]

Sounds like a great system.

A few things I learned from my install:

-You, essentially, have two 12v systems: System1: main distribution panel, system 2: "always on" system (tongue jack/electric leveling, emergency brake, possibly co2/smoke detectors, etc). I have the 70a Orion DC-DC converter for my distribution panel. I also have a separate 25A for the "always on" system. These 2 systems have different "shut-off" switches for obvious reasons. You may have to run new wire from some of your current hardware to the new battery location.


-Onan generators recommend 450 cca battery to start. Trying to find a DC-DC converter or "Buck Booster" that had the capacity to start the generator was a massive cost. It was easier to just keep a "small" 12v "starter" battery for this. You may want to consider keeping a generator starter battery next to the generator in the front compartment. cable runs are shorter and you don't have to mess with converting 24v into 12v for it. To keep my 12v starter battery charged, I bought a VIctron Bluesmart IP22 charger which is plugged into the back of the main distribution panel with the wiring to the 12v battery. This was a simple solution that took advantage of the solar/inverter so I didn't have to come up with a complete separate system (however I do loose a little efficiency in the conversion from DC to AC then back to DC).
I installed the IP22 in a interior cabinet next to the distribution panel. Hasn't gotten in the way yet


-Oversizing wires/cables is better than under sizing. When sizing my wires/cables I used 2% voltage loss on everything...whether it needed it or not. I'd rather spend a little more up front, then to risk a fire that would destroy thousands of $$ of equipment/RV. If it was borderline between 2 sizes, I went with the larger size. Even with a 24v system I still have some 4/0 and 2/0 cable.

-Cerbo GX is more capable than I thought. I am making use of the programmable relays available with the Cerbo. I have 2 fan circuits that are connected to these relays. One runs cooling fans for the Cerbo and batteries, and the other for the Inverter and Solar Charge controllers. I have temp sensors in each area. Once the temp exceeds about 100 degrees the fans switch on. When the temp drops below 90 degrees the fans switch off. Below you can see the 2 "fan circuit" temperatures. Because they are both below 90, the fans are not running. IF you are interested in running heating pads or anything that you want a prgrammable relay to control, use the Cerbo. It works great. (You can even use it to automatically start your generator if the battery bank drops below a specified level).


-Spend the extra $ to get the Touch 70 over the Touch 50. The extra 2" makes a huge difference when your eyes get old. In the pic below you can see the visual difference vs the Touch 50.



-Spend the time to do it right. Planning and preparing and leaving enough time to trouble shoot, make necessary adjustments, and make sure things fit/work is well worth it in the long run.


Please keep us posted on your build. Sounds excellent!

Thank you sir! Fantastic and detailed response and very much appreciated. A couple of questions/comments?

You don't think two 24v-12v 70-amp redundant converters will suffice for the always-on 12v and separate switch-controlled 12v to the distribution panel? I figured the "always on" 12v coming from the converters, each with their own breaker to the same bus bar would work and I'd leave the existing 12v keyed switch to the main distribution panel intact. And I'm also not so sure I see the obvious reason to have a shut off switch to the "always on" as one does not exist now? (I don't want to get too hung up on this minor point, as its easy enough to add another breaker/switch betwen the 12v source and existing always-on bus-bar connection to your point.)

What temperature sensors did you use that work to trigger the Cerbo GX relay? I have the design and purchased 4 relays to auto-start my Onan (3 DELAY OFF, and 1 DELAY ON time relays) via the Cerbo GX, but am unfamiliar with the temp sensors inputs? I was figuring I'd have to explore using the EG4 Server Rack Battery temp data to trigger some events on the Cerbo, but am still researching options and your suggestion sounds perfect! I want to automate all I can.

I already ordered the Touch 50 because I didn't think the 70 would fit in the spot I wanted it, right above the OneControl screen.

And yes absolutely spending the time to do it right! Its why I'm pouring over details and bouncing thoughts & ideas amongst you fine like-minded individuals! Thanks again for your excellent write up and I will keep you informed as I go - my Victron equipment arrives Tuesday and I will document this build well, and share.

-Chris

[acoleman43]

Thank you sir! Fantastic and detailed response and very much appreciated. A couple of questions/comments?

You don't think two 24v-12v 70-amp redundant converters will suffice for the always-on 12v and separate switch-controlled 12v to the distribution panel? I figured the "always on" 12v coming from the converters, each with their own breaker to the same bus bar would work and I'd leave the existing 12v keyed switch to the main distribution panel intact. And I'm also not so sure I see the obvious reason to have a shut off switch to the "always on" as one does not exist now? (I don't want to get too hung up on this minor point, as its easy enough to add another breaker/switch betwen the 12v source and existing always-on bus-bar connection to your point.)

What temperature sensors did you use that work to trigger the Cerbo GX relay? I have the design and purchased 4 relays to auto-start my Onan (3 DELAY OFF, and 1 DELAY ON time relays) via the Cerbo GX, but am unfamiliar with the temp sensors inputs? I was figuring I'd have to explore using the EG4 Server Rack Battery temp data to trigger some events on the Cerbo, but am still researching options and your suggestion sounds perfect! I want to automate all I can.

I already ordered the Touch 50 because I didn't think the 70 would fit in the spot I wanted it, right above the OneControl screen.

And yes absolutely spending the time to do it right! Its why I'm pouring over details and bouncing thoughts & ideas amongst you fine like-minded individuals! Thanks again for your excellent write up and I will keep you informed as I go - my Victron equipment arrives Tuesday and I will document this build well, and share.

-Chris

Good question about the always on system. The factory wires this system directly to the batteries (via a self-resetting fuse used for protection. Because mine is a bumper pull, that fuse is located on the tongue of the trailer). Because you're going 24v, you will have to have something that steps down the voltage for that system...you cannot connect directly to your batteries.

I'll go over my system a little to show you how I navigated everything.



Below is my initial diagram of what I wanted. Notice the Big Batteries were my initial plan. This changed. I also changed other things a long the way, but this gives you an idea.

Basic flow: Batteries to Lynx Distributor. From Lynx Distributor through a main cut-off switch, to a Lynx shunt/Lynx Distributor. From that Lynx distributor to 4 DC lines: Line 1 to the Multiplus (via a shut-off switch), line 2 to the Main DC busbar, Line 3 to the Solar Charge Controller for roof panels and line 4 to the Solar Charge controller connected to side port for portable solar panels.

The main DC busbar is where I split my DC systems. There are 4 posts on the busbar. Post 1: DC input (from Lynx Distributor), Post 2 to 70a DC converter (to main distribution panel through another cut-off switch and a fuse), Post 3 to 25a DC converter (through a fuse - for always on system), and post 4 to another busbar that isn't shown here. This secondary busbar powers the Cerbo, and all the fans I have running. That will be a different post





The pic below is actual system as it was in progress. You'll find you have A LOT of wiring to deal with .

The 70a DC converter is lower right and the 25a DC converter is middle left. The Maxi fuses are to the DC converters.

Also, there is a 600a busbar just below the 70a DC converter. This is my main ground busbar. almost all grounds to all my equipment go to this busbar. The busbar then goes to the chasis to complete the chasis ground.






This pic below is when things were a little more finished. The large black cut-off switch is the main DC cut-off switch. You turn that off, and ALL DC power is shut-off to ALL systems.

The red cut-off switch is to the main distribution panel. This replaced the factory cut-off switch (which is no longer in use).

My always on system doesn't have it's own cut-off switch. TO cut-off power to that system I would have to use the main DC cut-off switch. Also, the 25a DC converter is wired directly to the factory self-resetting fuse on the trailer tongue. From there is goes to the tongue jack and emergency brake (my co2 and smoke detectors are all battery powered). It was much easier to have a separate DC-DC converter for this system and using most of the factory wiring to finish it off. By doing this I basically plugged into the existing wiring from the factory. Less work for me to do.

The red and black cables on the floor are for the 4 batteries (at this point they were not installed). The black mat is a rubber mat use to absorb small movements for the batteries sake.






Below you can see the Multiplus was placed above everything (where I had space) with it's own cut-off switch to the right.

Also note the vent just above the Multiplus. Ther is a fan behind that vent that will suck air from the solar charge controllers (hatch below that area). THer is also a fan above the multiplus that blows air upward where I added an exterior vent (out of the picture).

Also notice the multitude of black vents. I really put an effort into air circulation....I hope it actually works lol. So far no issues with equipment

[acoleman43]

csommers4 for the programmable relays. I explained how it is done in this thread. Start with post #35

https://gdrvowners.com/forum/operati...make-one/page3

There are only 2 programmable relays available. Use them wisely

Also, if you are interested in using the Cerbo to track propane levels, it's super easy to do...and it's wireless. See this discussion if you are interested:

https://gdrvowners.com/forum/propane...-with-cerbo-gx

I have my Cerbo near all the other equipment, but in it's own special "hatch". It's a hatch in the bottom of our closet. Note the small fan next to the Cerbo. It sucks air from the bedroom (which should be cooler) and passes it over the Cerbo and out the other side into the exterior storage space.




Next project is adding Seelevel 710-AR sensors to my fresh, grey and black tanks, connect to the Victron GX Tank 140 which will plug directly into the Cerbo and give me fresh, grey and black tank readings on the Touch 70. Much more accurate readings. When I do that (probably later this year) I'll post about it. Crossing fingers it will work.

[csommers4]

I've completed the base installation of the system. Batteries were installed under the bed, with two 2/0 5' cables running from them to the Lynx Distributor. Blue Sea 6006 master switch cutoff shuts down the entire rig, two Orion 24v to 12v 70amp step-down with 80amp breakers to feed always-on 12v for jacks and then feeds 12v factory switch in basement. 6/4 from factory transfer switch and new run to electrical panel.



I used a HDMI extension for the Cerbo from the Touch 50 screen on panel above the OneControl, and ran 12v wire from the "always on" busbar to a 12v USB converter to plug into the power feed for the Touch 50.


Next up is having the Cerbo auto-start the Onan 5500, using 1 programmable relay for NO and NC output to send to additional relays that will slice into the generator start/stop wires, to mimic the start and stop sequences: Prime (hold STOP 6 secods), Start (hold START for 5 seconds), and finally STOP for 3-5 seconds to stop. (The Cerbo cannot issue these sequence commands therefore additional mechanical programmable relays were needed.) I want to have the system start the generator when the batteries reach 10% SOC, and shut off when reaching 99%. Additionally if high loads are detected I want the system to auto-start the generator, etc.



Courtesy of Eric K and his very helpful YouTube video of how he achieved this. I've seen other posts related to this, and I went with his suggestion of using 3 Gaeyaele GRT8-B (Delay OFF) and 1 Gaeyaele GRT8-A1 (Delay ON) in the lower left of this document below:



Here is his YouTube video walk-thru link:
https://youtu.be/hpo9UpHj5ZM?list=PLtlZgqPn7AiUp4dg1Rr61Fzquwp3zjtZ 4

This system is bolt-on solar ready. Just need the panels and the charge controllers! Thank you for all your help all!

[acoleman43]

csommers4 Very nice work. Looks fantastic.

Did you come up with a solution for the 12v starter on your generator?

[csommers4]

csommers4 Very nice work. Looks fantastic.

Did you come up with a solution for the 12v starter on your generator?

Yes. I kept the 12v lead-acid battery intact and compartment including the vent out, and wired a trickle charger to it that is connected to the old converer outlet by the panel. Was a long run but it will take care of the 12v starting needs for now.