Battery Bank Limit?

[Framus]

I'm currently in the middle of a build and purchasing the 400w solar kit from Renogy. They make no mention of how many batteries they suggest and from researching the issue, there's no answer. Sorry for possibly being a complete noob here but is there any limit to how many batteries I can connect to my setup?

[Danjo]

Based on your panel output, figuring optimal conditions of 5 sun-hours per day with perfect angle of incidence, you’ll be able to generate about 166Ah/day.

How much you store depends on how much of that you use, so start there. Make an energy budget. To do that, collect the wattage and how many hours per day you’ll use of your various electronics. This will get you Amp-hours per day.

Example

LED lights 10 light string at 9W each for 5 hours a day

10x9x5=450Wh

Convert to Amp-hours (assuming 12 Volt system)

450/12=37.5Ah

You’ll also want to figure in Days Of Autonomy. It seems like most calculations use 3 days in case you have poor sun for 3 days. So in the example above you’d want to store 112 Ah to run that string of lights.

When considering battery capacity, for lead acid batteries like AGMs, you’ll want to only use 50% of the battery capacity. So using that same example above you’d want to have a capacity of 225Ah

[Framus]

Originally Posted by Danjo

Based on your panel output, figuring optimal conditions of 5 sun-hours per day with perfect angle of incidence, you’ll be able to generate about 166Ah/day.

How much you store depends on how much of that you use, so start there. Make an energy budget. To do that, collect the wattage and how many hours per day you’ll use of your various electronics. This will get you Amp-hours per day.

Example

LED lights 10 light string at 9W each for 5 hours a day

10x9x5=450Wh

Convert to Amp-hours (assuming 12 Volt system)

450/12=37.5Ah

You’ll also want to figure in Days Of Autonomy. It seems like most calculations use 3 days in case you have poor sun for 3 days. So in the example above you’d want to store 112 Ah to run that string of lights.

When considering battery capacity, for lead acid batteries like AGMs, you’ll want to only use 50% of the battery capacity. So using that same example above you’d want to have a capacity of 225Ah

Thanks, Danjo. I will def look into that. I did fail to mention I want to go with the Battle Born LiFePO4 Deep Cycle 100Ah batteries.

[Danjo]

Check out their FAQ

https://battlebornbatteries.com/faq/

[Shorty Wandermeyer]

Hi Framus and Banjo...great timing on this post. I just purchased 400W Renogy kit myself and was doing some head-scratching on the battery issue myself. I have also added a 3000W pure sine inverter and am planning on having my solar batteries feed into the inverter and run pretty much everything on 120V. The inverter recommends a minimum of 200Ah battery bank.
I'm just beginning my build and historically have not done much off-grid camping...mostly in state parks w/hook ups but wanted the option just in case. Is it unwise to not run any 12v in the rig if I have an inverter? Am I missing something?

[Ronnie]

have the 400 watt renogy kit and 220 amp hr of batteries. Seems to be a good balance to me. I did upgrade to the MPPT controller after about a year. It was worth it especailly on cloudy days.

[Danjo]

Originally Posted by Shorty Wandermeyer

Hi Framus and Banjo...great timing on this post. I just purchased 400W Renogy kit myself and was doing some head-scratching on the battery issue myself. I have also added a 3000W pure sine inverter and am planning on having my solar batteries feed into the inverter and run pretty much everything on 120V. The inverter recommends a minimum of 200Ah battery bank.
I'm just beginning my build and historically have not done much off-grid camping...mostly in state parks w/hook ups but wanted the option just in case. Is it unwise to not run any 12v in the rig if I have an inverter? Am I missing something?

In my opinion you would be better off trying to stay 12V as much as possible since a lot of 120V household stuff isn’t designed with efficiency in mind. You’ll also take a hit in the conversion of AC. It’s better to take the hit converting to DC while plugged to a pedestal.

I’ve kept all DC, but I have a fairly simple setup with just lighting, refrigerator, water pump, water heater igniter, stereo and outlets to charge phone and tablet. I did include a 1000W inverter in the design to charge tool batteries, but I ran a crock pot on it and I think I’ll be doing that some.

My setup is six 100W panels fit to the curvature of the roof, so never optimal, a 60A controller, 400Ah of AGM batteries and a 1000W inverter/charger. So far so good.

After some summer desert camping I may add a small generator that is capable of running a mini-split. I’m going to wait to see how my travel habits work out before I actually do it.

[Ronnie]

I have also kept as much 12volt as possible, all lighting, water pump, fans , vents, and cell phone charging. 1000watt inverter to run the fridge, lap top, charge our scooter, and charge boat batteries for a trolling motor.

[Shorty Wandermeyer]

Thanks for the input and quick replies! The rationale behind keeping certain things on 12v makes good sense. In my scenario I'd probably keep my fridge, A/C, electric tankless water heater, and GFCI outlets on AC power and put lights, water pump, fans and USB charging stations on 12v. Does that make sense? Sounds like I need a converter now.
Do you happen to have a good wiring diagram for a set-up like the one we're talking about? I'm a better plumber than electrician

[ACamper]

Before you guys send Renogy and money you should look at some reviews and experiences others have had with them. They offer no support and they are fraudulent scammers.

Many of their kits are arriving with out the most expensive parts, many kits are not arriving, if something is broken or missing you are most likely out of luck.

I ordered some stuff from them and was lucky to get my money back, they are liars and scammers.

--------A few Renogy Reviews

https://support.renogy.com/en/suppor...cs/35000017025
https://support.renogy.com/en/suppor...cs/35000017584
https://support.renogy.com/en/suppor...cs/35000016308

https://www.bbb.org/us/ca/ontario/pr...stomer-reviews

https://www.trustpilot.com/review/renogy.com

[Shorty Wandermeyer]

Good to know ACamper. I haven't opened the box on the kit yet...sounds like I better make sure it's all there. That's why I order damn near everything off Amazon. I may pay a few dollars more here and there but as a Prime member I can return it w/no questions asked. I read a few bad reviews...but vastly more good reviews. Having worked for Dell for 13 years I know that even great products don't always arrive as they should...I also know that there are some folks that just will never be happy with things. I try to look at the big picture w/respect to reviews. But your cautionary tale has motivated my tail to go open and inspect all items received immediately...so thank you.

[Ronnie]

Must say Renogy has been great for me though. And great technical service too. Just my experiance.


The electric tankless water heater will draw a lot of power. Shore power or a generator is almost a must for that. I use a propane tankless heater, and propane for the stove too.

[TruculentTurnip]

I don't know about their customer support, but I've been very pleased with Renogy panels thus far. I have ordered 18 100w panels through Amazon so far for various systems over the past couple years and all have arrived undamaged and are producing within tolerances - and similarly to other manufacturers' panels in the field.

[Shorty Wandermeyer]

Re: Tankless electric heater...I have been figuring on using electric for both the cook-top and water heater mainly because I'm working with such limited space that I don't have an easy place to safely store the propane tank. I'm not a fan of having them strapped to the rear bumper etc. and there's no room in the undercarriage to build in a tank box. This is my first bus-build so I thought I'd start out with a short bus (baby steps). Turns out that my biggest lesson may be space utilization.

[ACamper]

Originally Posted by Ronnie

Must say Renogy has been great for me though. And great technical service too. Just my experiance.

How long ago did you get the products and use support ? Because for the last year or two they have not had any real support, usually 1-hour hold until they hang up.

***I would recommend anyone thinking about buying Renogy give their support a call and see if there is actually support.

Originally Posted by TruculentTurnip

I don't know about their customer support, but I've been very pleased with Renogy panels thus far. I have ordered 18 100w panels through Amazon so far for various systems over the past couple years and all have arrived undamaged and are producing within tolerances - and similarly to other manufacturers' panels in the field.

Most panels are very similar these days many companies are selling the exact same panels with different branding.The only real difference is support, which Renogy has none. Along with unscrupulous business practices.

[Danjo]

Originally Posted by ACamper

Before you guys send Renogy and money you should look at some reviews and experiences others have had with them. They offer no support and they are fraudulent scammers.

Many of their kits are arriving with out the most expensive parts, many kits are not arriving, if something is broken or missing you are most likely out of luck.

I ordered some stuff from them and was lucky to get my money back, they are liars and scammers.

--------A few Renogy Reviews

https://support.renogy.com/en/suppor...cs/35000017025
https://support.renogy.com/en/suppor...cs/35000017584
https://support.renogy.com/en/suppor...cs/35000016308

https://www.bbb.org/us/ca/ontario/pr...stomer-reviews

https://www.trustpilot.com/review/renogy.com

Oh yeah, now here I am writing on this thread and not realizing that the deal has not gone down.

I have a Renogy setup and while I’m satisfied with the quality of product, I can attest to the absolutely dismal customer service, especially after the sale.

It’s too bad. I don’t know why they would let it get so bad.

[TheHubbardBus]

Originally Posted by Danjo

It’s too bad. I don’t know why they would let it get so bad.

AFAIK all their manufacturing is done in China. I'm guessing COVID here & there likely has something to do with it, assuming this is a recent change. I'm actually amazed at how many electronics-focused businesses are not (yet?) total sh*t-shows after the year we've had.

[Doktari]

I asked Renogy a technical question about a product using email once. A tech answered, about a month later. They did apologize for the tardy reply.
Several AC efficient appliances I really like to have: induction plate, Instapot, water tea kettle, bread machine, Ninja. Ive gotten my propane use down to a minimum. I love having a inverter. I was surprised how efficient a bread machine is and wonderful fresh bread is. And it’s really easy to do. Dollop some butter on warm bread. That’s good stuff ! Depending what time of day it is and how sunny it is I break out the Honda inverter technology generator. But if I make bread at midday I don’t usually need it. My batteries are 200ah lithium. About as small as I would go. I would get 400ah if I could afford it. With lead it would need to be 300-400ah.

[Framus]

Appreciate all the feedback and opinions. If I still go through with Renogy, it'll be through Amazon to avoid that customer service nightmare for sure. But back to my initial question, is there any limit to how many batteries I can connect to my setup? If I had unlimited funds, is there any downside (besides space) to overdoing it with a battery bank and getting 4, 5, 6+ for a 400W solar setup?

[BeNimble]

If you go lead acid batteries, they do best when fully charged, so if you go too big, they might not get fully charged often. For lithium, they prefer to NOT be fully charged, so you can go as bigger is better.