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Signature Solar EG4 in RV. Bad or good idea?

mbab

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Greetings all. Just found the DIY Solar Power Youtube channel two days ago and this forum today. This is my first post and hope to be of help to someone.

I'm looking for a highly cost effective but very safe battery solution for a new travel trailer. BattleBorn and other similar are an easy choice except for the cost. Larger battery packs like the Signature Solar EG4 are highly interesting. They are lower cost per watt/hour and the weight would be less than the equivalent watt/hour stack of BattleBorn units. But I'm not familiar at all with rack mount packs. Is there something about such packs that would make an RV install a crazy, bad or dangerous idea?
 
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I dont have personal experience with the EG4 or any other rackmount type battery. I do have some general thoughts.

Battleborn and similar reputable 'drop in' type batteries are designed with a vehicle based environment in mind. The design model will have factored in and tested for this type of usage, and they've been around long enough now that medium term real world experiences are plentiful. And (at least in theory/ideally) issues in the physical design will have had time to be identified and/or improved. TL;DR they are designed with vehicle based systems in mind, and the combination of track record and warranty give some confidence there is not a high failure rate for this or any other use case. If you look at the construction, there are things that make a BB battery well suited to harsher physical conditions.

The EG4 and other similar rackmont style batteries (I believe) are assembled from larger form factor prismatic cells (<--actually I'm not sure what cells the EG4 uses) and were not designed/assembled with vehicles in mind. This does not necessarily mean they will be a bad fit in a vehicle, especially a big RV that stays on pavement, but it does mean to me that I would have a lower baseline of confidence in the suitability. Combine that with the relative newness of their popularity (both large form factor aluminum prismatics, and the rackmount type batteries among DIYers) and that is an even bigger question mark (in my eyes). Conventional wisdom in the marine electrical world is keep prismatics below 200Ah per cell, and ideally below 100Ah per cell for marine use cases. I think a semi-rough (dirt roads, washboard, etc) vehicle based use case would be pretty similar. There are lots of people using large form aluminum prismatics in vehicles, but virtually all are only 1-3 years in. So medium term real world experiences are still mostly a little ways off.

I don't know what cell size Gyll (or E-Gyll or whatever the company assembling the EG4 batteries calls themselves now), and I don't know too much about the build quality with respect to vehicle specific factors (constant mechanical vibration, and big mechanical shocks if off-pavement). I do believe the build quality is good in general, at least they look to be pretty robust and reviewers seem to have good things to say about build quality.

Also worth noting, there is a huge range of vehicle based use cases, you've got the interstate cruising land whales with air ride suspensions on one extreme, and at the other extreme you've got true overland vehicles spending as much time off-pavement and off-road as on it. Where you fall on that spectrum will dictate your priorities to some extent.
 
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If you look at the construction, there are things that make a BB battery well suited to harsher physical conditions.
There is no denying that a BB or Renogy drop-in unit it built for even the most rugged-use campers. Will Prowse's review of the EG4 showed the design was excellent and the construction very good. I found myself evenly split on an RV application based on what I could see in the video. Hopefully someone will have tried it before me and offer some feedback.
The EG4 and other similar rackmont style batteries (I believe) are assembled from larger form factor prismatic cells (<--actually I'm not sure what cells the EG4 uses) and were not designed/assembled with vehicles in mind. This does not necessarily mean they will be a bad fit in a vehicle, especially a big RV that stays on pavement, but it does mean to me that I would have a lower baseline of confidence in the suitability. Combine that with the relative newness of their popularity (both large form factor aluminum prismatics, and the rackmount type batteries among DIYers) and that is an even bigger question mark (in my eyes). Conventional wisdom in the marine electrical world is keep prismatics below 200Ah per cell, and ideally below 100Ah per cell for marine use cases. I think a semi-rough (dirt roads, washboard, etc) vehicle based use case would be pretty similar. There are lots of people using large form aluminum prismatics in vehicles, but virtually all are only 1-3 years in. So medium term real world experiences are still mostly a little ways off.
You echo both my hopeful thoughts on the possibility and my trepidation factors. I am not highly versed on different cell designs so your reply is quite educational.

I don't know what cell size Gyll (or E-Gyll or whatever the company assembling the EG4 batteries calls themselves now), and I don't know too much about the build quality with respect to vehicle specific factors (constant mechanical vibration, and big mechanical shocks if off-pavement). I do believe the build quality is good in general, at least they look to be pretty robust and reviewers seem to have good things to say about build quality.

Also worth noting, there is a huge range of vehicle based use cases, you've got the interstate cruising land whales with air ride suspensions on one extreme, and at the other extreme you've got true overland vehicles spending as much time off-pavement and off-road as on it. Where you fall on that spectrum will dictate your priorities to some extent.
My hope is that my non-off road application is compatible. Overall your concerns appear to be purely mechanical which is where my mind is. I couldn't imagine that anything about this form factor electrically would make it an inherently poor choice so I'm glad your omission of such concerns validates my thinking on that front.
 
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@mbab please check with the vendor and report back.
I did submit the question to Signature Solar and hope for an answer soon. I have no reason to think I would get inaccurate advice but wanted to see if I could get real world feedback as well from forum members. I'll certainly report what I find out!
 
I did submit the question to Signature Solar and hope for an answer soon. I have no reason to think I would get inaccurate advice but wanted to see if I could get real world feedback as well from forum members. I'll certainly report what I find out!
Its also good to see how responsive there pre-sales support is.
Not that it will necessarily co-relate with there post-sales support but if they give it to you in writing that mobile is supported I would consider that a very good sign.
 
Just my opinion on a travel trailer…

In a travel trailer, you probably will not be using the rack mount system (not enough space). Each battery is 100a @ 48v - how many batteries were you thinking of using?

This will be a 48v battery. So you will need a 48v inverter/charger, 48v solar charge controller, 48v to 12v converters (with enough amps to run all your 12v stuff). It’s all do-able - there will just be items to figure out.

How many 12v amps does your biggest items use? Slides? Stabilizers? Emergency brake away brake
 
Thank you Signature Solar for the report. Certainly a highly interesting option to consider.
 
Just my opinion on a travel trailer…

In a travel trailer, you probably will not be using the rack mount system (not enough space). Each battery is 100a @ 48v - how many batteries were you thinking of using?

This will be a 48v battery. So you will need a 48v inverter/charger, 48v solar charge controller, 48v to 12v converters (with enough amps to run all your 12v stuff). It’s all do-able - there will just be items to figure out.

How many 12v amps does your biggest items use? Slides? Stabilizers? Emergency brake away brake
See what you think of this line of reasoning....

My battery choice in 2019 was a single 12v 100Ah Battle Born (with 4x100watt panels). It has worked just as excellently as you'd expect from any well-executed lithium application. But with our new travel trailer we're gearing up for multi-month travel and want the option to occasionally run our 15k BTU AC unit for 1 to 3 hours in a 24-hour period. Doing this at Battle Born pricing makes that out of the question for our budget.

Enter the EG4. The rack mount was incidental. What I saw when looking at the EG4 was a power dense form factor with 5.12kW capacity from 16 A grade cells weighing 101.4 pounds for $1500.

I am looking at the 24v option to escape the trappings of high-amperage 12v operation. https://www.signaturesolar.com/products/24v-200ah-lifepower4-battery-by-eg4

Here's the (approximate) numbers that have my attention when comparing EG4 and SOK against my Battle Born. A single EG4 is compared against 2 SOK and 4 Battle Born in order to get roughly equivalent capacity:

Battery Options1 of EG4 24v 200Ah2 of SOK 12v 206Ah4 of Battle Born 12v 100Ah
Capacity5.1 kWh4.9 kWh4.8 kWh
Storage Volume1931 cu. in.2087 cu. in.3153 cu. in.
Weight101.4 ibs106.4 lbs124 lbs.
Cost1,4992,0583,196 (the old, non-heated)

Even against the excellent SOK option, the EG4 holds a strong position. For me, the EG4 pricing means the difference between sizing a system to include AC or excluding AC completely. In such a case I'd either just run a single SOK and be done with it or buy a second Battle Born. Either would easily fill our electrical needs without including AC. When choosing between these three options there are many other factors to consider I know but these foundational comparison points have started to build a compelling case!
 
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Just my opinion on a travel trailer…

In a travel trailer, you probably will not be using the rack mount system (not enough space). Each battery is 100a @ 48v - how many batteries were you thinking of using?

This will be a 48v battery. So you will need a 48v inverter/charger, 48v solar charge controller, 48v to 12v converters (with enough amps to run all your 12v stuff). It’s all do-able - there will just be items to figure out.

How many 12v amps does your biggest items use? Slides? Stabilizers? Emergency brake away brake
What I didn't say is that our 12v DC needs are small. All LED lighting, 1 slide, manual stabilizers, propane fridge, hot water and heat, 3 roof fans. That was the case in our previous camper and in 3 camping seasons totaling about 30 weeks we ran out of power 1 single time and that was only after losing 2 of our 4 100watt panels and the remaining 2 were in a heavily shaded group of trees. Our 12v use in the new camper measures only a little more than the old so I don't think we'll need a very expensive 24v to 12v DC to DC converter. Our A/C loads are very minimal as well if you leave out the roof AC unit. Including the roof AC is what has us essentially quadrupling (or more) the size of our prior system.
 
correct! as long as the operating temperature recorded in the BMS log does not drop below 0degrees F for discharge and 32 for charge
With our Battle Born (I know others do this) the BMS specifically addresses the low temperature situations you mentioned. Will does a nice job demonstrating this in several videos by placing the temperature sensing lead from the BMS into a glass of ice water and demonstrating that the BMS cuts off discharge or charge.

Do the rack mount units assume installation in temperature controlled environments and thus do not have thermal shutdown protections?
 
If the new trailer comes wired for 12V, with an inverter, 12V load panel, etc. why go 24v?
Seems like using the 12V model of the same style pack would be a cheap and easy installation. the 12V version is 400ah.

Yes, the rack style units from Signature include low voltage cut off, but they don't include a heating pad to keep the warm when it's below freezing, so you need to think about how to keep them warm when you need to use them in winter. I would assume you'd be keeping the trailer above freezing either way, if you were traveling anyway, but you do need to think about it.
 
Regarding the EG4 in an RV
must they be installed flat or can they be installed vertically?
 
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