Easy method to balance the Toyota hybrid battery (NiMH) 

My friend if the dog bite you. You can't bite the dog, just ignore the hater and carry on doing well done.

Be careful when adding batteries to this balancer. Ensure the modules being inserted into the group have a voltage close to the other batteries on the balancer. Otherwise a lot of amps may flow very quickly into/out of the battery being added to the group. You can use a SkyRC charger to charge the group of balanced batteries @ 5.2 amps total, however I recommend charging the modules one module at a time. The reason is each module has different capacities and resistance. When I charged the whole pack up to 8.30 volts, when I discharged some of the modules, their mAh capacity dropped considerably. I used to think it was the electrical connection of the aluminum strips on the balancer. But even when I connected the modules with copper wire using nuts, I had similar strange results. When I charge just two modules together in parallel, the discharge capacity is lower than expected. I think this is because the charge being applied is too low, and somehow the batteries with more capacity will take on more of the charge, and the modules with more resistance will be charged less. I have found that if you want strong discharge amps, you need to charge an individual module with 3.0 amps or 3.2 amps. If you charge the modules when connected in parallel, the charge amps are much lower (per module). When you discharge the modules to test them, some of them will have much fewer mAh than before. I also decided to track the temperature as the modules are being charged. If you have a charger similar to the SkyRC charger, you can buy a temperature probe for about $10. I would cut off the charger at around 82 F. In the summer, you obviously will have a different cut-off temp. I noticed my Prius pack can sometimes get up to 125 F (at a time when the pack was not paired up properly). When pairing modules up for the pack, it is important to pair them up, first on resistance, and then mAh capacity. Do NOT pair weak modules with strong modules (formula for pack failure). I noticed that when charging a module @ 3.0 amps up to 8.60v, the module got warm (about 82 F) and the module expanded. After doing this, the total capacity went up to about 3000 mAh, and it took a charge of 3236 mAh. Keep in mind the modules I tested were old and were the best of the modules that did not make the cut when I rebuilt my hybrid pack. Over time, I came to the conclusion that charging @ 3.0 amps is safer than 3.2 amps. However, I have found it beneficial to charge a module a few times @ 3.2 amps up to 8.60v to get the module to get it discharge more normally. After a few cycles charging @ 3.2 amps, I will switch back to charging @ 3.0 amps. I tried clamping two boards around the module to prevent it from expanding. This helped reduce the swelling, however this causes the module to get warmer more quickly, so I like charging a single module with a fan on it, and turn off the charging when the temp gets to 82 F. I noticed the module starts getting warm at 8.500v (80 F), gets warmer when the voltage is at 8.550 volts (81 F), and gets warmer when at 8.59v (82 F) (each module will be different and hopefully this improves with each cycle). Note: the voltage I am referring to is the actual module voltage, that my custom Arduino code captures for the one second (every 30 seconds) which is when the SkyRC charger is not charging. The SkyRC charger thinks the voltage is more like 8.70 volts, but when it stops charging, the voltage is closer to 8.59 volts. Note: the max voltage a Prius module can store is about 8.60 volts, and Delta V is triggered at around 8.72 volts (if it gets triggered). The SkyRC charger usually does NOT detect Delta V (which occurs when a module is fully charged).

This is the best method to balance the cells. I also used this method 4 years ago & saved lots of customer money. 👍👍

I also can appreciate your sense of humor and free spirit brother. Lately, RU-vid is trending towards 20-minute video length, only a suggestion. Thank you for the physics lesson for the folks who don't understand this portion of electronics/electricity.

You are a great sensei! Thank you, for sharing your knowledge. I am a retired tech who never got hybrid training and between you and the Weber State Auto gentleman, I feel confident that I can bring my 2011 Prius back to life.

I can't tell you how much I appreciated this. Thanks again Jose.

Bro you're doing great work to educate tech's like myself, who are here to learn from you & admire your efforts in putting this together, huge work👍 As for haters, they will never stop hating people who are helping other's & sharing knowledge Keep up the great work Bro, Stay Safe & Thanks for sharing👍

All this knowledge for free. Thank you sir.

he takes too long

By the way you don't have to thank us for watching we have to to thank you for those educational videos thank you very much.

Ingeniously explained. Even I, as a complete layman, understood that. Top!

Those aluminum bars is a very clever solution for voltage balancing. Having experience witth LiPo, LiFePo4, lead acid batteries and BMSes (battery management system) I know that same voltage doesn't mean that each cell has the same capacity (often cells are degenerated by heat). Cells in the middle of a battery pack get hotter, so best practice is to swap them with the cells on the outside. A thermal camera (very affordable these days) can give you insight about the temperature difference between cells and their condition (bad cells tend to get warmer, too). To recondition, 3 cycles of discharge and charge each cell (with approx. 0.6C - 0.8C and cooling) with 30min rest in between is pretty efficient. Could make a huge difference in capacity. For RC there are great chargers available that aren't expensive. NiMh doesn't like trickle (slow) charging.

Thank you for sharing your expertise with us. Now I am ready to charge and balance the high voltage battery in my Prius C.

Hey thanks for taking the time to make this video. I'm about to change busbars on a 2010 Prius and balancing hadn't even crossed my mind until I saw this, so going to do it at the same time. Thanks bud! 👍

Your explanation for bringing it to balance was very understandable.thank you.

Men you are the best I'm totally agreed with you thanks to shared all that information

Just took out a 2007 battery that was "reconditioned, balanced" 3 months ago by a "Prius Battery Specialist". It was failing because balancing is a waste if the Internal Resistance is high on the modules. I picked the lowest IR batteries from my 3 packs and the car drives like new. Voltage is secondary. IR is the most important parameter for series-connected traction batteries.

Excellent video. I have duffed and experimented with replacement and balancing of hybrid cells within the hybrid battery pack, and finally arrived at the thinking you present here. Wish I had seen this video when I began my fact finding journey.

Just come across your videos Jose, thanks for the content and sharing your knowledge. The automotive industry is starting to shift once again and this information will be something all technicians will need to acquire! Disregard the haters! Great content and delivery! No matter what we do in life there’s always someone with a negative view. Just keep doing you 👍🏻.

Thank you so much for taking the time to teach us these really neat tricks.

Great channel! Here in Brazil hybrid vehicles are recent, I'm learning in this great channel.

Thank you for teaching us I appreciate you ignore the haters cause they do not have followers

Thanks you for all your teach.

Great video. Could you provide specs on the balancer or do a video on how to complete and where to get the parts, what size wood board, bolts...etc?

Amazing technic. Thumbs up

Great demo. It’s very interesting the way you explain it in the simplest layman’s terms. Thank you.

Excellent! You have a awesome sense of humor!

Mr jose loved every minute of your video 🙏🙏🙏

Hey Bro, thanks for sharing your knowledge on Hybrid Systems. You are doing an amazing job. Keep it up.

Great video, I will be cleaning and inverting the cells as you me tioned on my 2011 prius, I dont have the balancer, can I still install them and let the car charge them? Or is it required to balance them before install? I have the V on prius app. And about 3-4 degrees higher on battery #2 compared to 1 and 3 as seen on other videos that you have explained due to heatstress. If highly recommended I will balance them, is there another alternative to do this other than prolong balancer?

Hi Jose, I stumbled upon your videos and really LOVE them. I’m sure I could figure out the measurements of your balancing mechanism on my own (by measuring one of the cells - I haven’t removed any yet) but I was wondering if you’d mind sharing the materials/dimensions of your brilliantly designed device? Thanks so much!

Great video, love your lessons. Thank you and keep your positive attitude!😊

Great 👍 Definitely learning Experience. Thank you.

This method does charge each battery to same voltage. But, if any cell has less capacity (volume of current capacity) when cells are place in series (as they are in auto battery pack) they will fail to provide as much current as needed to keep up with other higher capacity cells in series battery. This method balances for same voltage but does not sort out cells with different storage capacity.

Great Video, Can I ask how your balance table is made? Is it just a plywood bottom? Are the bars on the top aluminum?

Love the rig u made. But it was a rreeeaaaallllyyyy long way to explain what could have been said in about 1 min.

You are a lifesaver you are a golden💪

fantastic idea guy

Great video, thanks for the info

Man you are doing a great job

Great video! Thank so much for sharing knowledge ans experience!

Awesome work, and very informative!

You are a mad Genius!! Thanks !!

Thank you, it was very useful

Very informative and excellent work again bro👌👍

when you have them all connected in parallel and you measured the V on the aluminum, and you get 7.10 v. You when checking the individual, also will show the same because at every point, you are measuring the overall volts. YOU need to lift a unit UP and test it so it is not touching the aluminum bar - and compare the before and after voltage for it - as you said, they become in balance very very slowly - then you do this wrong and say they are coming in balance very quickly :) I have my batt all apart right now and have 5 modules that are bad - 3 of them are below 2 volts and one shows 6.32 and the other 7.02vs. All others are within the limits of 7.6v. I also made this "tool" and will leave mine for 48 hours and see if this will truly bring them all to equal voltages - will let you know. I have recorded each cell "present/before voltage so then I can see if it got discharged or charged up in the balancing process".

Nice job Jose. 👍👍👍 Perfect jig for checking charge and balancing. Is it your design? How long does it usually take for balancing for one, two, or three bad cells? Shouldn't you be wearing gloves? Everyone who owns a hybred or full electric should watch this video. I just subscribed.

I think that this is a good way to balance, but if I am going to go through the trouble to have a battery out, I would want to cycle and load test the batteries, specifically checking capacity variance. Part of how they get imbalanced in the first place is internal resistance and ACTUAL capacity variance between each individual cell. That way I can toss out any weak performing cells and get a better net product.

I have a question,,,Those batteries inflate when they get charged or balanced which cause the battery to degrade if they are not packed or hold by any means and ventilated to remove the heat disipated.. That is why they are packed close on the module.Can you comment on that?

Is it possible to trickel charge the cell while they are in parallel on the mechanical cumustomised aluminum balancer device you made? In theory, can you start with balancing all the cells. Once they are all balanced, slowly charge the cells by hooking the charger up on the aluminum rack and slowly charge the cells up. Wouldn't this reduce heat "loss" and the cells would charge more quickly? When the charging is done, then just disconnect the charger and let the balancer rest a few days. Done! Thoughts?

Thank you one of the best Video 👍

Thanks for your vidios very importan for loren alat

Instead of charging the complete pack can the batteries be charged individually. For an aqua what is the individual cell voltage and what voltage should they be charged? Thanks for the videos they are great.

i love these videos at 1.5X speed...❤❤😂😂

Quick question what would be causing higher temperature reading on Dr Prius on Battery Temp 3 block 10-14

Hello, my very simple principal question. Why is such a big deal balancing the modules so closely!? I understand if there's a big difference but what if they are about 0.5 volt different? The other thing is do you load test them before balancing them. How about if they have different capacities under the load even if they have almost the same voltage!? Thanks

Very imformative video but quick question do you need to fully charge the modules before balancing them ?.

Awesome work

I was curious if balancing the modules actually improved the modules, so I explored balancing the pack more, and I have a theory of what happens when you balance the modules. After balancing the modules, I charged them individually @ 3 amps up to 8.50 volts, and then tested their discharge time. For some of the modules, their capacity dropped dramatically (to 20% of their previous capacity). However, after cycle charging/discharging them a few times, the capacity came back. What is going on here? I think what may be happening is that when you balance the modules, the electrons flow back and forth much more, causing clumps of material to become dislodged. I think this back and forth action is similar to how water in a swimming pool moves back and forth when someone jumps in the water. I find some older modules have a hare time keeping the voltage at 8.20 volts. A module that cannot be charged higher than 7.2 volts likely has a bad cell, and should be discarded. Charging a balanced pack up to 8.40 volts for 12 hours likely is safe. Doing this step will likely bring the voltage of all 6 cells in each modules up to 1.4 volts each (8.40 volts / 6 cells). Balancing the modules this way is dangerous so BE CAREFUL! Make sure + to + ALWAYS, and also make sure a module's voltage is close to the pack when adding it to the balanced pack.

If balancing is so effective to equalize modules then why we need expensive equipment to recondition them: charging/ discharging…?

I just want to ask question I am using ultra power up 240ac plus -once recycling three times with 7300mAh they stop over capacitor Do need recycle again or it’s fully complete Please give me Thanks Lakshman

Nice Idea boss welldone

You are a genius

You could alternatively get another set of bus bars and connect each module pair to its neighboring module pairs. You'd have to remove the orange plastic thingy, but you're doing that anyway to clean the bus bars.

Los mantenimientos a la hv de la Nissan kicks E-Power se hacen similar como está batería???

What test i much used thanks you.

What type of metal was used to mount the battery cells on to balance the batteries? I want to make one and just want to make sure I duplicate it as best I can. Looks like metal rails, nuts, bolts and wood support. Thank you!

I have learned a lot from your videos. I have one bothersome question: You show balancing with the Prolong battery Charger in a video, and your mechanical customized balancer in this video. When would you use one or the system, or would you use both for a reconditioning?

Thank you very much

Hello! Thanks, very useful.

Simple and amazing

Hi Do you have a video on how u made the balancer ?? Can u please post the link .thank you.

Jose, what is the full voltage on a battery and a white voltage is supposed to charge it. The reason I ask is because I have 20 complete battery pack and I’m planning on using them as a home battery back up system at 48 V a total of 560 modules

There are 6 cells in one battery module. With this method, you only equalize the voltage of the batteries. However, the 6 cells of the battery can have different charges.

Nice what are the Measurements of your board I’d like to make one

Ive made the same setup for balance battery

I have one fresh out of my 2015 if anyone needs it. Probably just needs serviced. The refurbished one is working for now. 760.

I think you should update the title to reflect the type of hybrid battery NiMH (Nickle Metal Hydrate). I believe the method shown on this video won't work for Lithium Ion hybrid batteries.

The way I did it, is I discharged and then charged, measured the Mah, and only put ones that where 7000mah and up.

Great work

Hi Jose, Great channel. Really appreciate it. I have 2 questions regarding charging. Is a 1 amp NOCO Genius charger sufficiently small to collectively charge a Prius Gen 2 hybrid battery without causing overheating. Secondly, if I make balancing "machine" like yours, will I run the risk of having cells expand if I add charge while they are on the balancer?

when you say low current a value would be nice to know what you consider low. Also the low nominal and max voltages would be apreciated so I dont have to guess. thanks

The weak module still stays weak. What you get when you combine them in parallel is the total voltage of the two cell modules in parallel. Same as the ordinary flashlight cells, if the flashlight has two week cells and you replaced only one of them with new, it will have a higher total voltage but the old unreplaced cell will remain weak.

Where would you recommend I buy the modules from?

Thanks brother 😊😊😊😊

Is it useful to change the order of the slides site to make a balance

Thank you sir for sharing this video the balancing of battery was something new just one question sir how would I be able to knw that what module is really bad and has to be thrown and and which one can be revived

Is there a training course we can take for hybrid vehicle systems?

Hey I have a question so I do a load test on the hybrid battery pack with some light bulbs and the cells that discharge faster I replace with other cells that hold better and the ones that discharge faster I throw away does this mean the cells are not bad they are just unbalanced

Would laying a metal coat hanger that you straighten out do the same thing as building a balancer?

My sister's husband died and she left his 2006 prius sitting in the drive for about 5 years in her grief. The main batteries were replaced right before he died. I'm helping her get rid of it now but have no clue if those batteries can be expected to be good. She doesn't want to tow it to a mechanic. I'm just trying to get some ballpark info here to maybe help her get a little money from it. Thanks for any info. Best. L.

can we re insurt the battery to the car without balancing the modules after cleaning the corrusion ?

Do you mean toyota have not installed an active BMS for these batteries? This means their quality is fenomenal and incredibiloid!!!. I have an RX400h with the original battery for almost 15 yrs. Incredible.

you should come up with again physical measurement of modules after 1week time th show how much balance has been done

The ioniq has a balance energy system inside or is necessary do the same process? If the answer is no, how often is necessary todo? Thanks and excellent videos

Does the 5th generation hybrid system with the lithium ion batteries have a self balancing system?

Fantastic!!!!

Like you video...! Hey Bro... Question if a module when you remove it has 6.7v and you charge it individually with an 8v charger for two days and after that the module returns to 6.7v is it already considered defective? Oh is it possible to revive it with the parallel load as you show here?

I am a little confused when you mesured the individual module voltage dont you need to take the battery off the balancing bar thing and measure it then? Cause it still in parallel dont you get the same voltage anywhere on the line? i feeel stupid all of the sudden.

Awesome, I’m gonna give it a try on my 2007 Prius! What was the name of that charger?