DIY SOLAR Battery Banks - Parallel? Series? Both??: What, Why & HOW! Beginner Friendly 

Want to make a comment without sounding like I am criticizing. I have worked as a mechanic for years. Best safety advice when working with batteries. To avoid shorting the terminals when connecting or disconnecting batteries. When connecting Always connect the Negative terminals last. When disconnecting Always disconnect the Negative terminals first. Less chance of accidently making contact with the metal wrench and causing shorts.

I used twenty big marine batteries. They're in 24 volts hookup. I used #2 welding leads on all battery connections. I have been off the grid for two years. I used an Aims 2000 watts inverter charger, 24 volts. I have 1400 watts of solar panels. I also bought a 600 watts wind generator last November. It helped a bunch last winter. I'm showing 24.8 volts at 6 a.m. I think I had six batteries when I bought the Aims Power inverter charger. It didn't start acting right until I hit 16 batteries. It's working good now with twenty. I had one battery go bad last summer in the heat wave. I couldn't get to it to check the acid in it. It shorted out and I replaced it a few months ago. I had to buy a 31 series because they don't make the 29 dp-dl anymore. My setup works okay. I ran the air conditioner off of it four hours yesterday. My inverter has a dip switch that changes the low voltage setting from 22 to 24 volts. I don't use the higher setting. If the voltage drops below 24.0, it wants to turn the charger on. I think that setting is for the batteries like you're showing here. I use the lower setting so that I don't need the gas generator. I have 25,000 watt hours. I built my system to run a small house or cabin. And to let me be able to build one. Well I enjoyed reading the comments. I'm at that point. I have enough batteries to go to 48 volts, but probably won't. The inverter would cost too much for me. Im on social security. And I would need another charge controller to have any more solar panels hooked up. Im using a 4215 BN , Epever 40 amps, 24 volts. Im pushing 34.5 amps through it around noon or one. Adding two more panels would put me right at 40 amps. Id rather not run it right on the edge of overload. The inverter charger Im using has went up from $769 to $995 since I bought mine. I had a 15% off coupon and mine cost $653. I had to replace the power and control boards in it once, after I ran a welder with it building my wood stove. I bought a Winco Lil Dog 3000 generator to run the welder after that. Well I got to look at the insides of the inverter charger. It has a heavy transformer. I thought maybe it could do it. I blew the tops off of five of the MOSFETs. Cost me about $400 to fix it. It's been working okay the last year and a half. I replaced the temp sensor in it too. It has to be in one exact spot to work right. Even if you turn it just a little bit, it changes how it acts. I was going to get a 3000 watts inverter but they were sold out of them at the time. I thought a 4000 watts was too high. And they're split phase. I've gotten used to this old single phase. I have a spare 2000 watts inverter but it's 12 volts, sucks amps. I use it in the pickup once in awhile. It doesn't matter about the amps, I just leave it running. I bought a bigger battery last year and enlarged the battery box a little bit. I put a 900 amps battery back in it. It works pretty well with that inverter. It just rained, clearing out, my system is making 789 watts.

Nobody explains it like you do. You are the best at explaining stuff.

Think I'm gonna attempt a diy for camping and power outages. You're info has been the best by far.

Your Humility just adds to this great video...

Another excellent explanation. As always, straight forward without any nonsense. Many thanks.

Finally some able to discuss battery topologies. Thank you very much!

thank you for your persistence each one

This looks shockingly simple to do ⚡💡

Thank you for sharing and very educational!

I was hoping you'd be explaining why many of these drop in replacement battery manufacturers state that their batteries may NOT be connected in series/parallel.

Excellent video! I like to tinker with stuff. This video will be helpful when I build my own portable system.

I really appreciate the effort you have put I making this video it the best of all it series on RU-vid ❤❤❤❤

This is the one I have been waiting to see, great job explaining this subject. Thanks... I plan on using an inverter with a built in charger.

God bless for teaching n solving my 2 battry setup...

What I needed to know is 24 volt system to a 12-volt system which one lasts longer on a converter drawing the same amount

This is excellent information. Well explained for a beginner (like me) to get started. Subbed. Thank you.

I'd had a read through on line about a 2s2p set up, my mercedes vario conversion is a 24v system to start with, so it just made sense to stay at 24v, elastic trickery has never been my strong suit. Hearing the systems explained in layman's terms is really useful, thank you for a great video, I confirms what I'd already read, but being a nervous kinda chap around electrics, having the confirmation in layman's terms is awesome, thank you

Great video. Thanks!

Thanks it was well presented and easy to understand 👍

All good and clear info. I'd like to see more about wire size to use, crimping tools and method. Many thanks!

Well done, makes total sense. Very much appreciated Thanks

Very useful information. Thank you!

Great video! Thanks for sharing.

That was one of the best, easiest explanations I have heard. Nice job explaining

One of the best explanation. Thank you sir👍

Awesome explanation! Thank you.

Very easily explained brother job very well done

Thanks professor , that's a good thing the i watch this video . I was going to change my battery bank to 24 volts and hook my 12 volt inverter to it ,,,, thanks again.

There is no doubt that your explainations are the best. I love the pace at which you explain the details. You never rush; you are clear and concise. After viewing any of your videos, I walk away with more understanding than I do with channels with similar content. I watch many wonderful RU-vid channel that do all sorts of product reviews and they do them well, but there is something awesome about your style. You don't over do it; awesome.

Great information 👍

Nice demonstration

Connecting multiple batteries in parallel will ultimately result in one of them failing over time. You replace it, then another one fails no matter how well they are matched. An expensive exercise. To avoid this, use battery isolators that use Schottky diodes that have a low forward volt drop of 0.7V. This ensures that the batteries cannot interact even though they are in parallel.

THANK YOU for doing the watt hour test with the same device on 12v and 24v. this question has been driving me nuts lol!!!! so its supposed to be the same.... slightly more efficient with the 24v (because the invert runs closer to 95% efficient)

Awesome info man

To build a system from scratch, starting very small and working upwards, can I parallel smaller charge controllers until I need something larger? Maybe a video showing us newbies how to upgrade would be a good idea.

All good tips & tricks! I especially liked that you proved a 24-volt inverter is more efficient than the 12-volt. Thank you...🇺🇸 😎👍☕

I like your videos, nice setup and quality of your videos 👍🏻

Super awesome. Thanks

Thanks alot. I knew some of but not all of this info. Right now im running 3 deep cycle lead acids parallel And didnt know that its better to have same cable lengths (tho mine arent too far off from each other), and to take positive and negative from opposite end batteries. Its almost 11pm and this video got me pumped up.. almost want to go out in the dark jus to tinker on the batteries lol ... To, as u mentioned, not put more demand on my one battery that has the 2 output terminals connected to it. My idea is to have the solar controller pos n neg on oposite end batteries, then the output on neg and pos that the solar isnt connected to (like an X when all reconnected. Thanks again.

Good presentation

This is the good stuff! Well done!

Subbed. I watched a few of your vids. You deliver a message well without all the hype! I bought 2 Dr Prepare batteries with the hubs. I went the hub way for now mostly so I could run two 12volt fridges for longer periods of time until the batteries need recharged again. My power stations can't run them for as long. One reason I went this way was so I could potentially consider setting them up for parallel in the future if I find the need for that on solar. For now, I'll use the "KISS" system until my needs change 👍 This video really helps to explain different situations! Thank you!

Very good video I am wanting to build the most efficient system to run a fridge and a upright freezer still haven’t found a video showing a good system with part lists and step by step instruction on building such system

Good video, informative.

Thanks for ur video. Pls can u list all items used .

Hi. Yes the video is informative. Thanks

NICE PRESENTATION,I WILL LIKE TO TAKE PART IN THE SOLAR GENERATOR WORKSHOP

Thank you.

Good Job!

Great video, thank you. Can you discuss a 4 battery, series/parallel(24 volt) arrangement. I am experiencing a "balance" situation with Redodo batteries, and will try a battery equalizer. When one battery discharges more than a half a volt from the rest the BMS stops the battery, and then the equalizer shuts down because there isn't 24 volts anymore. Keep up the good work.

That's good advice about not mixing up the voltage of chargers. I had one that was switchable between 12V and 24V, but one day I forgot to switch from 24V to 12... Are batteries meant to fizz?😬

I chose 24v to keep the wire size down and 24v high ah LiFePO4 batteries are now easier to find.

To get the most longevity out of your inverter you should mount it so the fans are blowing up. This works with the natural ability of heat rising and will lower the operating temperature of the inverter making it last the longest time possible before failure. Great informative video!

Do you add discharge amps when you have multiple batteries? Like 2 100a batteries that have a 100a max discharge rate will now have 200a max discharge rate? the higher discharge rate would handle like an RV A/C startup amp draw.

Well done

well explained

At the very least, it makes sense to install a fuse between batteries connected in parallel. A failure in one battery will place a load on the companion battery and allow excessive current to flow. The result of that could destroy the good battery and produce excessive heat with the very real risk of fire.

Great video. I'm a newbie at this, but wouldn't the extra efficiency of the 24v test setup have come from using the larger-than-needed cables from the 12v setup?

What’s the working of the BMS in parallel vs série configuration ? Is it limiting as a single battery.

Nice video.. And badass battery.. check 20kw power queen battery bank.. STRONG..

solid vid. 10/10

Nice video mate what was those tin wire were connected to the batteries I m doing 4x200ah 48v do I need balancer or BMS to keep the batteries under track what you suggested I be using this one solar backup system 8kw inverter

I bet the efficiency difference would have been even greater running fridge or a/c with a induction motor. That would be cool to see. I am planning to make the jump to 24volts soon for the gain in efficiency and to further grow my system.

Dude your awesome

Hi. I was wondering about my 24 v trolling motor. I would like to double the run time. Can I run 2 sets on 2 like batteries in parallel and then put them in series? Where would I connect the load pod and neg? What about charging? Thanks for any advice

Should the wires going from the inverter to the batteries be the same length or does it matter?

The length of the individual wires can vary, but the round trip length should be as close to the same length as possible for reasons you mention. It is the round trip or over all length that should be the same. This is easier since you can start with a 10 ft cable for each polarity, cut as needed for each connection. You can have varying lengths due to rack/mounting design. All 10 ft should be used.

Great video once more I just bought the 3 pack of these Power Queens on sale for $750, can I use just the three in series I want to power my Pecron E 2000 at night or on cloudy days or do you recommend the 4th so I can run a 24 volt parallel, 2nd question for my output from the batteries (8AWG) can I just run them into an MC4 to hook into my aviation plug? Thanks in advance and also for inspiring me to get partially off-grid :)

Can you also describe the Battery Cable sizes used in your Videos. Also the Lug 3/8 or 5/16. Thanks great videos

is there a tutorial of the entire set up? Including the solar control, breakers, etc....

Great Sir

Please can you also give a teaching on how to use a meter

Good video

I am running 2 x 24v 100ah Lifpo4 in Parallel with an all in one 24v Inverter Solar Charger. When under load one battery drops faster than the other, should they both drop at the same % roughly?

Loved the video! Great explanation, I now have a much better understanding of how battery banks work. I'm planning on getting solar for my home and was thinking of getting the smallest package available through Tesla without a powerwall and supplementing it with a set up as shown in this video. My average consumption of energy per month is 750 kwh. Any advice for me? your input would be greatly appreciated. Thank you

Perhaps I am mistaken but I looked at the comments and I watched the video a few times and it appears that you have connected the output of the Bouge solar controller to the inverter. My understanding is that the output should go directly to the battery bank and then from there to the inverter with the cabling being as close to the same length for all cables and the batteries cabled in a balanced configuration. Please reply or comment if I am mistaken.

What size AWG cable did you use between the 2 batteries as jumpers? Is it the same as the cables feeding the invertor (1/0 perhaps?)

Very simple; hybrid. Series adds voltage but not current, parallel adds current but not voltage. build in series to match your inverter, then tie the series strings together to get the desired current.

I have 2 12v batteries in series. I have a double bank 12 V charger. Do I need to use both banks to charge both batteries? Any harm in charging both batteries with both banks?

When connecting in series, use batteries of same capacity otherwise balance issues can arise, even with lead acid.If the set goes flat, then the polarity of the weakness battery may reverse. I build orr grid systems as a hobby, being a qualified electrical engineer for more than 50yrs. Like your video, great for beginner's.

When you have a voltage max cap problem start up in a battery, how do you tell fixable wear from permanent damage on a battery? Thanks.

So we have a 12-48v charger and 12-24v 6000w inverter running a well and other small things. Have it all ran in series with 12v batteries system which works but after a couple days of clouds we typically run out of juice... Would it be better to hook the last battery to 24v or no???

They get charged up to 14.5V for max cap with out over charging. but you CAN go to 14.8V. i do mine to 14.5 to be safe I have the WEISE version of them batterys (best for the money). Max low is 11.0V Max high is 14.8V 1C rateing (100A dis/recharging). I discharge mine to 11.5V and charge max 14.5V

Great info. Kind of sucks that they all need to be the same age and cycles. That makes it an all or nothing proposition. It'd be nice if you could add batteries as you go, and build it up, and when one goes bad, you simply replace it instead of replacing every one.

People are shocked when they find out I am not a good electrician 😂

When using 12v batteries in series always use a balancer so that the health of the batteries as well as the capacity is not compromised.

👍👌❤️🇨🇦, gr8 info, thanks for sharing

Question can 12/3 electrical wires be used for long run’s coming off a electrical panel if not then how do I do it for 100 foot runs thanks

I have 9 100Amp lifepo4 batteries and I want to make 24v battery pack. So is it possible to keep 2 batteries in parallel and others in series? What is the amp I can get? I am using jk bms as battery balancer and 24v inverter.

My simple theory about battery voltages is; If you have a need for DC power then use that voltage, beware of high currents! If you have a need for mains voltage then pick a high battery voltage for efficiency (no-one uses solar if they have unlimited mains!) At low volts the current must be high to make power which demands big wires and fat lugs and risks hot wire and hot connections -which are both inefficient uses of the stored power.

Hi,I watched your video with keen interest. I want to ask if it's possible to connect 2 200ahms 12 volt and 1 230ahms 12 volts battery together on an inverter. Would love to hear from you soon

I watched your video and saw nothing about using the batteries in series AND parallel connection. Say I have 36ea.2 volt cells and want to connect the in a 48volt inverter input. I’m going to have parallel and series cells in the string. Do it tie the parallel connections in @ middle of the string or at the end(s)?

Hot dog! I've just found my solar teacher!

What wire lugs are you useing?

hi, i dont think you covered this but since you plug positive and negative cables from inverter one to each battery, do you do the same with the solar charge controller? doing my first power queen setup with 2 batteries in parallel, 700watt renogy inverter and lion energy 400 watt solar charge controller. any help appreciated.

I juswt came accross this video, and decided to watch, I was hoping to see what way you went about using 4 of the same batteries for a 24 volt system. I am about to do that with my 4 lithium batteries, But being charged by 2 different controllers

Not sure if you cover it at some point and I just missed it, but it's crucial that the BMS in the batteries you're connecting in series or parallel are designed to handle that configuration. In particular, if one BMS shuts off and the other battery is pushing all of the current, can the BMS handle that?

So I'm wanting to run a 700w microwave and a TV and a game system part time and my 12v refrigerator freezer all the time I have 300 watts of solar and two 100 amp hour batteries, after only watching half of your video I'm pretty sure I need to go parallel because I'm way below 3000-watt ?

Do you need a BMS in this setup?