Battery refurbish in process - IMAX B6
#51
09-14-2011, 04:19 AM
Re: Battery refurbish in process - IMAX B6
Reagle,
Thank you. I'd like to say that I "fixed" the pack but I don't really know that I did. The fact is, I expected to find a couple of bad "sticks" of batteries in that junkyard pack, but I didn't. All I wound up doing is cycling the sticks a few times and putting it back together. I think the pack was good to begin with. So I just plain lucked out.
Had I found a stick or two and had to weld a couple together to repair it, then we'd really know if what I did was a real success or not. For now, this writeup really just serves to show how it could be done. I wish I could say it was more.
The balance charger I built did seem to make a difference when I used it. I've only taken the time to use it a couple of times. This was before this pack rebuild. I think I'd have used it more but never got around to putting the connector on the end. :-P I'll get some pictures up of the charger for those that are interested.
Thanks again!
Ross
Thank you. I'd like to say that I "fixed" the pack but I don't really know that I did. The fact is, I expected to find a couple of bad "sticks" of batteries in that junkyard pack, but I didn't. All I wound up doing is cycling the sticks a few times and putting it back together. I think the pack was good to begin with. So I just plain lucked out.
Had I found a stick or two and had to weld a couple together to repair it, then we'd really know if what I did was a real success or not. For now, this writeup really just serves to show how it could be done. I wish I could say it was more.
The balance charger I built did seem to make a difference when I used it. I've only taken the time to use it a couple of times. This was before this pack rebuild. I think I'd have used it more but never got around to putting the connector on the end. :-P I'll get some pictures up of the charger for those that are interested.
Thanks again!
Ross
Last edited by rossfree; 09-30-2011 at 03:45 PM.
#52
09-14-2011, 04:31 AM
Re: Battery refurbish in process - IMAX B6
Hi Regal,
Neither pack was very dusty. I never cleaned anything. I blew a light coating of dust off of one but that was all. No air-flow problems here.
No there aren't any fuses in the wires I attached to the pack. Just the two diodes. The diodes are power diodes and beefy with a breakdown voltage much higher than the pack voltages but I didn't put fuses in and probably should have. The trickle charger is limited to about 350ma of current so I could have used bell wire to do the job. I opted for rugged 12ga wire with a layer of spiral wrap for extra protection. That's actually why I don't have a connector on the end... nothing I had fit the dad-gum wire I picked! :-P
I admit, a fuse on each wire would be a nice level of safety... I'd place them up near the pack connections. Maybe I'll change out the wire to something more reasonable and while I'm at it, stick in some fuses. Maybe I'll also win the megabucks. I'm a procrastinator so this one might not get done. :-)
Thank you for your comments! You too Harold!
Ross
Neither pack was very dusty. I never cleaned anything. I blew a light coating of dust off of one but that was all. No air-flow problems here.
No there aren't any fuses in the wires I attached to the pack. Just the two diodes. The diodes are power diodes and beefy with a breakdown voltage much higher than the pack voltages but I didn't put fuses in and probably should have. The trickle charger is limited to about 350ma of current so I could have used bell wire to do the job. I opted for rugged 12ga wire with a layer of spiral wrap for extra protection. That's actually why I don't have a connector on the end... nothing I had fit the dad-gum wire I picked! :-P
I admit, a fuse on each wire would be a nice level of safety... I'd place them up near the pack connections. Maybe I'll change out the wire to something more reasonable and while I'm at it, stick in some fuses. Maybe I'll also win the megabucks. I'm a procrastinator so this one might not get done. :-)
Thank you for your comments! You too Harold!
Ross
Last edited by rossfree; 10-31-2011 at 06:41 AM. Reason: corrected trickle charger current from 50ma to 350ma
#54
09-17-2011, 06:45 AM
Re: Battery refurbish in process - IMAX B6
Ross:
Your addition of the 2 wires with diodes has piqued my interest (for long term battery health).
I'll not touch my IMA system until it if off warranty, which based on my driving habits will be in about 14 months (at 130,000 kms).
Then, I would like to become familiar enough with your set-up and with your experiences with same to hook something up as well...
Assume I know nothing about electronics, recharging, etc. Sounds like if one can 'trickle charge' the IMA battery when the car if 'off', one can add life to a used IMA battery.
First, to confirm where you connected your upgrade, I attached some shots out of the shop manual to clarify for myself:
The 3rd shot I have circled what I believe you have connected to.
The diodes, or one way gates if you will.....do both 'gates' allow flow only to go from the charger to the IMA connectors? Again, I'm out of my depth on this one (perhaps a circuit diagram would clear things up?).
If one were to buy the units you used, could you identify them from this site please: http://ca.mouser.com/Search/Default.aspx
Since one will trickle charge a 158V Ni-MH battery with your upgrade, what sort of charger will you use?
Sorry for all the questions on a minor sidebar to you main project, but having the ability to 'balance' a used Ni-MH battery whilst it remains in the car (i.e. trickle charge over night, use car in day, etc) really sounds exciting.
Thanks
Mike
I also have a picture of a couple of wires in my hand with red electrical tape over the ends. This is an external connection I made to the battery pack that allows me to trickle charge the battery from a charger I built. It's a very slowwww charge that should not hurt the battery pack but allows me to do a full charge and hopefully balance the pack. More on that later.
I'll not touch my IMA system until it if off warranty, which based on my driving habits will be in about 14 months (at 130,000 kms).
Then, I would like to become familiar enough with your set-up and with your experiences with same to hook something up as well...
I have a couple of shots of the cable I made to charge the pack. It's wrapped in spiral wire-wrap for an extra layer of safety. The closeup shows the connection to the battery terminals. These terminals have full pack voltage even with the car key off. It allows me to trickle charge the pack. Also note the bulges in the shrink wrap next to the connections. I have two diodes in series with the connections. Diodes are like one way check-valves for electricity. They allow electricity to flow in one direction and not the other. As long as I feed a higher voltage into the pack than the pack voltage itself, I can push electrons (current) through the diodes. But the pack can't push current through the other way. That keeps the other ends of the wires safe (I wrapped them in electrical tape anyway) I intend to get a connector for the loose end. Someday.
First, to confirm where you connected your upgrade, I attached some shots out of the shop manual to clarify for myself:
The 3rd shot I have circled what I believe you have connected to.
No there aren't any fuses in the wires I attached to the pack. Just the two diodes. The diodes are power diodes and beefy with a breakdown voltage much higher than the pack voltages but I didn't put fuses in and probably should have. The trickle charger is limited to about 50ma of current so I could have used bell wire to do the job. I opted for rugged 12ga wire with a layer of spiral wrap for extra protection. That's actually why I don't have a connector on the end... nothing I had fit the dad-gum wire I picked! :-P
If one were to buy the units you used, could you identify them from this site please: http://ca.mouser.com/Search/Default.aspx
Since one will trickle charge a 158V Ni-MH battery with your upgrade, what sort of charger will you use?
Sorry for all the questions on a minor sidebar to you main project, but having the ability to 'balance' a used Ni-MH battery whilst it remains in the car (i.e. trickle charge over night, use car in day, etc) really sounds exciting.
Thanks
Mike
#55
09-17-2011, 09:24 AM
Re: Battery refurbish in process - IMAX B6
Hi Navguy,
There is a good deal of information on trickle charging these packs out there. I admit that I am still a greenhorn when it comes to charging batteries. The best explanation I can give it that as a pack is used, charged and discharged, some batteries within the pack charge and discharge at different rates and over time they become somewhat unbalanced. When they are unbalanced they do not perform as well and your vehicle performance suffers.
Trickle charging slowly charges the batteries in the pack. As each battery reaches capacity, it begins to heat up. Batteries don't like heat and overheating shortens battery life. When you are charging a single battery in a typical household charger, the temperature is carefully monitored and the charger knows to stop charging. When you charge a pack, it is impossible to monitor the temperature of all 132 batteries. By trickle charging you minimize the heating condition in the battery as it reaches capacity. In this way, batteries that take longer to reach capacity can be given extra time to do so.
A typical charge period for a pack on a trickle charger is 24 - 36 hours. Some people power the fan in the pack to keep it cool while they charge. I don't really think that's necessary unless you live some place where it's already hot to begin with. I live in the Northeast and it's pretty cool here.
The charger is made by connecting several power supplies in series. Mine is made with three 48 volt dc power supplies and one 350ma constant current power supply (3 - 36 volt dc). Each power supply in series adds together to create a voltage supply of 147 to 180 vdc. The constant current supply will adjust it's voltage automatically to provide a constant current of 350 miliamps. If you read my posts earlier, you will remember that voltage is like pressure. The constant current supply raises it's "pressure" until it can push 350ma of current through the battery pack. Neat!
I think I spent about $150 building the charger. There really is nothing to it. I'll take pictures soon and list all of the parts I used. I bought everything from Digikey.
I think trickle charging about once a month is a good plan. Anything more often may be over doing it and might not be so good for the pack.
Thanks for your comments on the post.
Regards,
Ross
There is a good deal of information on trickle charging these packs out there. I admit that I am still a greenhorn when it comes to charging batteries. The best explanation I can give it that as a pack is used, charged and discharged, some batteries within the pack charge and discharge at different rates and over time they become somewhat unbalanced. When they are unbalanced they do not perform as well and your vehicle performance suffers.
Trickle charging slowly charges the batteries in the pack. As each battery reaches capacity, it begins to heat up. Batteries don't like heat and overheating shortens battery life. When you are charging a single battery in a typical household charger, the temperature is carefully monitored and the charger knows to stop charging. When you charge a pack, it is impossible to monitor the temperature of all 132 batteries. By trickle charging you minimize the heating condition in the battery as it reaches capacity. In this way, batteries that take longer to reach capacity can be given extra time to do so.
A typical charge period for a pack on a trickle charger is 24 - 36 hours. Some people power the fan in the pack to keep it cool while they charge. I don't really think that's necessary unless you live some place where it's already hot to begin with. I live in the Northeast and it's pretty cool here.
The charger is made by connecting several power supplies in series. Mine is made with three 48 volt dc power supplies and one 350ma constant current power supply (3 - 36 volt dc). Each power supply in series adds together to create a voltage supply of 147 to 180 vdc. The constant current supply will adjust it's voltage automatically to provide a constant current of 350 miliamps. If you read my posts earlier, you will remember that voltage is like pressure. The constant current supply raises it's "pressure" until it can push 350ma of current through the battery pack. Neat!
I think I spent about $150 building the charger. There really is nothing to it. I'll take pictures soon and list all of the parts I used. I bought everything from Digikey.
I think trickle charging about once a month is a good plan. Anything more often may be over doing it and might not be so good for the pack.
Thanks for your comments on the post.
Regards,
Ross
Last edited by rossfree; 09-19-2011 at 07:08 PM.
#56
09-17-2011, 10:35 AM
Re: Battery refurbish in process - IMAX B6
Ross
OK, I'll check it out.
Thanks for the logical explanation as to what a trickle charger can do for my battery pack. I suspect "the" software upgrade done to my '07 may induce a 'trickle charge' more of the time when I drive the car to address the very phenomena you describe.
Please and thank you.
Cheers
Mike
There is a good deal of information on trickle charging these packs out there.
Thanks for the logical explanation as to what a trickle charger can do for my battery pack. I suspect "the" software upgrade done to my '07 may induce a 'trickle charge' more of the time when I drive the car to address the very phenomena you describe.
I think I spent about $150 building the charger. There really is nothing to it. I'll take pictures soon and list all of the parts I used. I bought everything from Digikey.
Cheers
Mike
#57
10-02-2011, 06:02 PM
Re: Battery refurbish in process - IMAX B6
Quick update on this project:
The recals are all but gone! It's my wife's car and I drive it mostly on weekends but I haven't seen a recal in a long time! The car is peppy and with minimal effort I can get nice milage in the 44 to 46mpg range. For fun, I reset the mpg and odometer and took it for a 30 mile spin (looking for my cell phone). I didn't hyper mile, I just watched the mpg feedback on the dash and did what I could to keep it high. I got 52mpg for my efforts. So, with a little attention and minimal effort, you can get nice gas milage from this vehicle. That makes me happy.
When my wife drives she gets 37mpg. :-)
It's so nice not to see recals!
Happy Motoring!
Ross
The recals are all but gone! It's my wife's car and I drive it mostly on weekends but I haven't seen a recal in a long time! The car is peppy and with minimal effort I can get nice milage in the 44 to 46mpg range. For fun, I reset the mpg and odometer and took it for a 30 mile spin (looking for my cell phone). I didn't hyper mile, I just watched the mpg feedback on the dash and did what I could to keep it high. I got 52mpg for my efforts. So, with a little attention and minimal effort, you can get nice gas milage from this vehicle. That makes me happy.
When my wife drives she gets 37mpg. :-)
It's so nice not to see recals!
Happy Motoring!
Ross
#59
10-03-2011, 04:32 AM
Re: Battery refurbish in process - IMAX B6
Hi Regal,
Ya know, the jury just isn't in yet on that. I cycled all of the batteries from my old pack. I had a few that came in on the low side... around 5100 or 5200 (5300 to 5400 MAH considered being good). The rest seemed fine.
But... what is missing in these measurements is how LONG they hold a charge. NIMH batteries have a higher self-discharge than many chemistries. That said, they still do a descent job of holding a charge, but over a period of days or weeks, their loss of charge can be considered significant.
As I was connecting these old batteries I noticed that several had very little charge to begin with and some had a descent charge. It was noticable though I had no way of gaging the difference with the method I was using to cycle the batteries.
I cant' just measure the voltage of the batteries with a VOM. They really need to be reasonably loaded to do that. I suppose I could hook them all up, trickle charge the pack for a couple of days, then wait a week, put a load on the entire pack, and measure the voltage on each double stick of cells. That might give me some good numbers worth sharing. I could take readings every day over a couple of weeks. That should give us some real data.
Let me think about this... a plan is formulating! :-)
Ross
Ya know, the jury just isn't in yet on that. I cycled all of the batteries from my old pack. I had a few that came in on the low side... around 5100 or 5200 (5300 to 5400 MAH considered being good). The rest seemed fine.
But... what is missing in these measurements is how LONG they hold a charge. NIMH batteries have a higher self-discharge than many chemistries. That said, they still do a descent job of holding a charge, but over a period of days or weeks, their loss of charge can be considered significant.
As I was connecting these old batteries I noticed that several had very little charge to begin with and some had a descent charge. It was noticable though I had no way of gaging the difference with the method I was using to cycle the batteries.
I cant' just measure the voltage of the batteries with a VOM. They really need to be reasonably loaded to do that. I suppose I could hook them all up, trickle charge the pack for a couple of days, then wait a week, put a load on the entire pack, and measure the voltage on each double stick of cells. That might give me some good numbers worth sharing. I could take readings every day over a couple of weeks. That should give us some real data.
Let me think about this... a plan is formulating! :-)
Ross
#60
10-04-2011, 09:04 AM
Re: Battery refurbish in process - IMAX B6
Thanks for all the great info Ross. This is very helpful to the DIY crown that wants to take risks and hopefully rewarded with being able to service their own battery
I just replaced my original 06 battery high miles with an 08 battery with low miles + slow charged it to balance the cells. So far its a great success and I have improved mileage and got rid of the 3-4 daily re-cals.
However I'm not sure what to do with my old battery pack. I'm really curious if it was just one bad cell that was causing the re-cals. The pack is reading 169 volts right now so it can hold a voltage, but I'm curious what each individual pack has, and the capacity. I would need to buy the imax to test
I just replaced my original 06 battery high miles with an 08 battery with low miles + slow charged it to balance the cells. So far its a great success and I have improved mileage and got rid of the 3-4 daily re-cals.
However I'm not sure what to do with my old battery pack. I'm really curious if it was just one bad cell that was causing the re-cals. The pack is reading 169 volts right now so it can hold a voltage, but I'm curious what each individual pack has, and the capacity. I would need to buy the imax to test
