Build Hybrid Battery Maintenance Gear For Under $100

Remove HV battery from Prius and charge on a bench? Yes. Same connections for the grid charger, just reconnect orange disconnect if you removed it before moving hv battery. Also remember to run a cooling fan over or through the pack.

 

Great Thread. Anyone have a succinct parts list? Or is the Maxx Volt or Prolong the only option? Does anyone build these for sale?

 

Simplified DIY Grid charger, without discharger switching.

 

This thread has be very helpful for me. Thank you! I built a simple grid charger from what I learned here, which helped me keep the HV battery charged on my 2009 Prius while troubleshooting a P3191 failure. I've posted photos and descriptions of my charger as well as how to power the on-board cooling fan for the HV battery here: Grid Charger | PriusChat

 

Just wanted to thank everybody who contributed to this. Ultimately saving me buckets of dough.

That said, for folks who may not read all of the replies, there is a Youtube video contained within of Jose from Hybrid Solutions that features him rack charging modules from a 12 volt battery that I would strongly suggest people avoid duplicating. It's also well covered here that NiMH batteries require a very specific type of charging profile that isn't reflected in that approch. There's also mention of some poor unfortunate who lost an eye when their hybrid pack blew up (presumably while uncovered and they were working on it). My guess would be that rapid charging, as shown in Jose's video, was a likely culprit, but that's just my guess.

This is an over simplification, but different battery chemistries require different charging profiles, so if you're new to all of this, I'd also suggest that you spend a little time reading before you break out the soldering iron. This can help:

Learn About Batteries - Battery University

One of several cautionary images that I keep front of mind when working with any electricity is that of an instructor I encountered at an electronics training school eons ago when I first left the military. The fellow was teaching because he was tired of the rigors of high voltage field work, and one fine day he gave a lecture demo on the dangers of handling capacitors.

The short version is that while cavalierly illustrating the wrong way to handle caps, he accidentally discharged one that I believe had come out of a heart defibrillator, the very definition of what makes DC potentially fatal. His accident was initiated by an arc rather than physical contact, and the discharge found earth by jumping to his non-insulated screw driver, traveling up his arm, down the right side of his body, and down his right leg, before ultimately blowing a hole in the toe of his shoe and finding the metal kick plate of the counter in front of him. He survived, but barely, and I quit the class that day, deciding that demolition work was safer.

Another is that I recall a recent interview with Adam Savage, of Myth Buster fame, who had declined being Tased during one of their Fun with Tasers episodes. Of all of the crazy crap that those folks did, this was one of only two stunts that he refused to participate in. The reason? It only takes milliseconds at about 7 milliamps, to potentially interrupt your heart beat (and the Taser they tested ran frightfully close to that limit), so I look upon my hybrid batteries (stored energy that should ALWAYS be considered as hot) with the same level of respect that I give high voltage AC, which I have also unfortunately witnessed two people killed by in the workplace.

Don't mean to go all preachy, but while reading more than a few queries across this wonderful forum, I am constantly struck by the realty that there are a lot of members attempting to work on their hybrids who know even less than I about high voltage current, and that scares me, hence this commentary.

I buy and work on a lot of hybrids that previous owners have done all sorts of idiotic stuff to before deciding to get rid of them, so I remain vigilant that even with proper PPE's, there is no accounting for the actions of the latest and greatest improved idiot. I've also read of more than one instance where a hybrid pack had somehow energized the vehicle body, so even though the batteries are well protected, I always check when servicing, and make disconnecting the hybrid pack the very first thing. Another prudent practice is to work with one hand not give electrical current a path to ground that might pass through your heart.

Also worth mentioning, especially for folks who kinda know a little about batteries, but not necessarily a lot (like myself - but I'm still learning) is that our older tech NiMH batteries have an alkaloid electrolyte rather than the more common acidic one found in lead acid batteries. The result is that if you do get burned by effluent, treat with a mild acid, like white vinegar or boric acid as soon as possible (I keep white vinegar in an eye-wash station in my shop, just in case). Also be mindful that when it contacts aluminum, hydrogen gas is emitted, and that's the stuff that made the cover of Led Zepplin II so memorable.

Ignoring hazard & risk assessment can easily outstrip anything we save in DIY.

Battery Risks: (any of them can kill or maim)

Thermal
Chemical
Shock
Arc Flash

Okay, sermon over.

 

Can any one suggest similar HV charger for 2007 camry?

 

I think what you need is adding more of such MEANWELL sort of power supplies or whatever brand you want, serially, to output loke 300VDC, seeing that the camry pack comprises of 34 modules in total.
There is nothing special about the Camry, or even a Highlander hybrid, which i do work on on a regular.

 

Hey, I'm new to all of this battery stuff and I got some questions. At this moment I have a grid charger from Maxx volts for 2004-2009 Prius, my question is, is there any difference between this charger and a charger for 3rd generation? I mean both of them have the same voltage output and the same amount of modules (expect the amount of wires for fan) I'm asking this because I got both of them and only now I realized they're basically the same. Another question is, what do you think about discharger in this video?

I've been looking to do something like this but not sure. The author is basically using a 600w lump to discharge the battery. Also what do you think about Venice Hybrid Tech in general? I heard some bad rumors about them. Last question is, I got Toyota Camry Hybrid 2008 and I want to try charge/discharge cycles to restore the battery (it's failing, SoC of 24%, *freeze time date) I need a discharger for this purpose but don't want to spend another 400$ to buy a new one, any ideas where I can get one for cheap? (maybe I could build one, just not sure if I can, my skills is not good enough). So I planned to use the Maxx volts charger even if it's not for Camry and to buy or to build a discharger so I can do reconditioning without taking battery off. Thank you in advance and sorry for my stupid questions.

 

Thank you for clarifying some things for me! So, either way it's a grid charger for a whole pack or a hobby charger for induvial modules.

I didn't see the discharger in the video because you didn't give a time stamp on where it is and I looked for it and it was no where to be found... But supposedly a low amp discharge of 1/3 of an amp gets the best results and higher amp discharges are less efficient. What you really want is a machine that optimizes the amp load based on remaining capacity so it gets done perfectly.​

starts at 2.59. It's not a discharger but rather a wire connections to positive and negative terminals on a hybrid battery, that's connected to the 600-Watt Halogen light which works as discharger.

What you really want is a machine that optimizes the amp load based on remaining capacity so it gets done perfectly.​

Where can I find machine like that?

 

I think they all came from the same design. I bought the grid charger from Venice Hybrid Tech for $300, don't want to shell out $400+ on the Prolong or Maxx stuff. I just want a quick way to grid charge my cheap Prius and bring it to life, I could assemble that grid charger for less than $300 (maybe around $100) but it will take me a while to source out the parts and I want something cheap and tested. I talked to the guy "Raj" and he's very knowledgeable about the HV batteries. I was able to revive my Prius and recently my friend's Prius was also revived with their grid charger (replaced 4 bad modules) Here's what inside of it..

The voltmeter is powered by 9v battery and there's no cooling fan. Tons of ways to revive the HV battery, it's just that their approach is simple.. you could take the complicated approach but it takes time and money.

 

Will this charger also perform the.discharging? What wiring harness should one purchase to go along with this?

Thank you!

 

Hi! I see this charger has a 200v 1 amp option for $199 and 300v 1 amp option for $299 as of today. For prius the 300v is needed correct?

 

I personally have a Maxx volts charger, so I not sure about this one, but the nominal voltage of prius hv battery is 7.2*28=201.6v, since you have to 'overcharge' the battery at slow current of 350mA (or less) for at least 16 hours the voltage would go up to 230-240v. So, for the prius you need more than 200v.

Btw, what are you planning to do? A top balancing or reconditioning?

 

Ah thank you for confirming. I'm thinking a reconditioning. Why do you ask?

 

If you're going to do the reconditioning, you may need to build a light bulb discharger. I suppose you can also use the power supply (but that's only 1A).
Here is a link to Hybrid Automotive on how to perform the discharge cycles - Light Bulb Discharger User Guide – Hybrid Automotive