dnmun
1 PW
i thought you were going to have 42S for cell count. i see no reason you cannot get a solution from bestechpower. for a lot less money.
Finally bought one
- Thread starter yopappamon
- Start date
yopappamon
10 kW
dnmun said:
You are probably right. I think it will be 48s. I didn't see where to purchase on their site. Where did you buy?
MitchJi
10 MW
Hi,
For a manual LVC alarm you could use Cell Logs like this:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=37121&#p539682
I didn't know that it has any "charger circuits". Doesn't it consist solely of cell level HVC and LVC?yopappamon said:
For a manual LVC alarm you could use Cell Logs like this:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=37121&#p539682
If you use the mini BMS 4S boards you don't need to mount a module on the cell, and you could connect them to the existing BMS connectors:yopappamon said:
dnmun said:
It will probably work. Sounds like the best solution, if you can make it work (please let us know if you do!).fechter said:
yopappamon
10 kW
Yeah, the circuitry on the left is the charger cut off. The right is the cell monitoring.
I've seen the cell log boards, but I wanted the high end balancing circuits.
I didn't know that MiniBMS had boards like that. The thing I don't like about their controller is it doesn't know the difference between lvc and hvc. And at $12 per cell, more expensive.
I've seen the cell log boards, but I wanted the high end balancing circuits.
I didn't know that MiniBMS had boards like that. The thing I don't like about their controller is it doesn't know the difference between lvc and hvc. And at $12 per cell, more expensive.
MitchJi
10 MW
Hi,
Excellent Volt Pack thread here (long - 19 pages):
http://www.diyelectriccar.com/forums/showthread.php/2012-chevy-volt-battery-93101.html
Including this post:
http://www.diyelectriccar.com/forums/showpost.php?p=379925&postcount=128
I was not disagreeing with your choice, just trying to supply additional information.yopappamon said:
Excellent Volt Pack thread here (long - 19 pages):
http://www.diyelectriccar.com/forums/showthread.php/2012-chevy-volt-battery-93101.html
Including this post:
http://www.diyelectriccar.com/forums/showpost.php?p=379925&postcount=128
yopappamon
10 kW
I understand, Mitch,I didn't take it badly. I appreciate the input and welcome critiques. I've learned a lot from the discussions.
Janzicek is Josh Anzicek. By sheer coincedence he lives 25 miles from me. He came to my house and helped me get my controller reprogrammed. He gave me a huge volume of test data from his cells.
I need to ask him if its OK to share the data here.
Going to try to drive to work to tomorrow.
Janzicek is Josh Anzicek. By sheer coincedence he lives 25 miles from me. He came to my house and helped me get my controller reprogrammed. He gave me a huge volume of test data from his cells.
I need to ask him if its OK to share the data here.
Going to try to drive to work to tomorrow.
yopappamon
10 kW
Drove to work this morning.
16 miles, 15 AH. Head lights on, normal driving. Never touched the brake, the regen is powerful enough to stop me quick enough. Started at just over 200 volts, ended at about 192 volts. 55mph takes about 1.1ah per mile, maybe a little less. Recover some of that when stopping. 35mph probably around 0.7-0.8ah per mile. Overall around 0.94 AH/mile. Cells were around 4.17v at start, around 4v after.
Charging back up at work now. Not totally sure my range, so not pushing it until I know for sure.
16 miles, 15 AH. Head lights on, normal driving. Never touched the brake, the regen is powerful enough to stop me quick enough. Started at just over 200 volts, ended at about 192 volts. 55mph takes about 1.1ah per mile, maybe a little less. Recover some of that when stopping. 35mph probably around 0.7-0.8ah per mile. Overall around 0.94 AH/mile. Cells were around 4.17v at start, around 4v after.
Charging back up at work now. Not totally sure my range, so not pushing it until I know for sure.
oatnet
1 MW
Nice job! Now you need a CA in there so you can get a figure for watt-hours. 
Starting voltage seems high if you care about pack longevity - you will get more range out of the pack that way but for how long?yopappamon said:
The LEAF for example only charges to 4.10v at "100%", 80% is around 4.01V and once you get down to around 3.5V you're pretty close to empty. Car shuts down at 3.0V.
I believe that the Volt charges to about 390V at full and discharges to around 330V at empty - or about 4.06V / cell when full and 3.44V / cell when empty.
yopappamon
10 kW
That is a very good point. With that I mind, I watched the system as it charged tonight. There is a 9ah difference between 4.06v and 4.17v. That's 20% of the pack. FRom what I've heard, the Volt cells have a lot of capacity near the top of the charge. This test supports that. I have some charging curves from Josh, I'll look at them tomorrow and see if his pack is the same.
I only charged to 4.1v tonight. About 3.7ah below 4.17v.
I really need to test the cells capacity so I can better manage my charge and range.
I only charged to 4.1v tonight. About 3.7ah below 4.17v.
I really need to test the cells capacity so I can better manage my charge and range.
dnmun
1 PW
since you have no BMS to protect the pack the biggest risk you have is over discharging one of the cells. charging to full voltage does not kill the cells but leaving it at full charge especially in hot hot weather shortens cycle life.
The CellLog board looks cool, but not suitable for keeping connected to the pack all the time. They run hot and don't discharge the cells evenly.
The units from Bestech Power can probably be used to simply drive a relay or optocoupler to drive an alarm. Daisy chaining more than one may require a little relay board or some other kind of interface that handles the voltage differential. There may be ways to daisy-chain them directly without relays or optos. One downside is you are limited to fixed voltages and have to take what they offer. I don't think you can change the voltage settings.
The units from Bestech Power can probably be used to simply drive a relay or optocoupler to drive an alarm. Daisy chaining more than one may require a little relay board or some other kind of interface that handles the voltage differential. There may be ways to daisy-chain them directly without relays or optos. One downside is you are limited to fixed voltages and have to take what they offer. I don't think you can change the voltage settings.
yopappamon
10 kW
Excellent point as well, dnmun. I only top charge at home and it sets over night. Might be best to charge a little higher until I get the BMS.
yopappamon
10 kW
Separated the long set. Some M6 threaded rod to put it back as two sets.
dnmun
1 PW
you should be able to make flanges for your cooling channels by using some plexiglas plate and then using a threaded tubing adapter screwed into the surface, make gaskets or fit O rings and use those threaded bosses above and below for the screws to hold it on.
i keep thinking that the solution might be using two 24S packs in series and use two different 24S chargers charging through their individual BMS. this is where you could use two of the power boards on the lower BMS, maybe even 3 if you needed that much current, and then use all the balancing boards from the BMS the power board is removed from.
4 of the D131 balance boards give you about 360mA balancing current and about 480A on the output, assuming the current would be balanced between the power boards during discharge. four means two balancing boards on each 24S section.
for the output just bypass the mosfets on the upper pack, and use the output mosfet on that upper section to drive an led that could be used to signal hitting the LVC on the upper pack. put that led on the dashboard to monitor.
since this is not a situation i would expect the controller to be left on and drain down the battery i don't see risk in losing control over the LVC on the upper section. but i would retain the control for shorts on the output so that protection would remain intact for the battery.
i am now a big believer in using the cellogs too, for cell level monitoring. so you should be using them and if you go over to richard's hack thread on the cellogs you will see otmar's depletion mode mosfet hack for the 8S source of power to the voltage regulator, and that allows the cellogs to be used without draining the first 6 cells only.
that would get you to a functional monitoring and control system for the pack until something better comes along. the balancing is so crucial, getting the balancing current up is so important for these large packs to get them to balance quickly.
i keep thinking that the solution might be using two 24S packs in series and use two different 24S chargers charging through their individual BMS. this is where you could use two of the power boards on the lower BMS, maybe even 3 if you needed that much current, and then use all the balancing boards from the BMS the power board is removed from.
4 of the D131 balance boards give you about 360mA balancing current and about 480A on the output, assuming the current would be balanced between the power boards during discharge. four means two balancing boards on each 24S section.
for the output just bypass the mosfets on the upper pack, and use the output mosfet on that upper section to drive an led that could be used to signal hitting the LVC on the upper pack. put that led on the dashboard to monitor.
since this is not a situation i would expect the controller to be left on and drain down the battery i don't see risk in losing control over the LVC on the upper section. but i would retain the control for shorts on the output so that protection would remain intact for the battery.
i am now a big believer in using the cellogs too, for cell level monitoring. so you should be using them and if you go over to richard's hack thread on the cellogs you will see otmar's depletion mode mosfet hack for the 8S source of power to the voltage regulator, and that allows the cellogs to be used without draining the first 6 cells only.
that would get you to a functional monitoring and control system for the pack until something better comes along. the balancing is so crucial, getting the balancing current up is so important for these large packs to get them to balance quickly.
MitchJi
10 MW
Hi,
Are those plates, or something similar on all of the exposed sub-packs on the original pack?
Because if they are, it looks like those plates on the end might be used to compress the modules, to prevent the pouches from puffing?
yopappamon said:
Are those plates, or something similar on all of the exposed sub-packs on the original pack?
Because if they are, it looks like those plates on the end might be used to compress the modules, to prevent the pouches from puffing?
He is planning to use two 48S packs in series.dnmum said:
dnmun
1 PW
i saw the 200V and he had said 48S so that was what i thought he was gonna do. but the principal is the same. just need 4 of the 24S chargers, use 4 of the 24S lipo D131 for balancing and charging the 4 24S packs. or consider using the D170 instead.
yopappamon
10 kW
MitchJi said:
Yes, you can see the black plate in the picture in the back.
Been driving for two weeks. Really like this little car.
I'm getting 140 MPGe. 280 if you factor the my work is paying for half my charges.
yopappamon
10 kW
The ladies love a guy with an electric car!
Got all the groups rearranged in 24 cell groups.
Got all the groups rearranged in 24 cell groups.
yopappamon
10 kW
Got the two groups I've been driving with ready to turn on their side. Used metal shipping banding to wrap up the top. The one didn't have the original metal band as I reduced the size. Ran the banding through 1" aluminum tube (which I wrapped with electrical tape) and 1/4" rubber to build the top out so it will lay flat on their side. Upright the trunk top will not fit back n, the cells are too high.
yopappamon
10 kW
Just did a capacity test. Started at 4.16v down to 3.53v and got 38.87ah. This lines up with the test data I got for Josh on his pack. He tested his from 4.25v down to 2.7v and got 44.4ah.
So I think my pack is close to the rated 45ah.
30ah should get me to work and back if I for some reason couldn't charge at work.
Should have a useful range of around 40-45 miles. 80-90 miles when I get the other two groups put in.
Ran the AC while testing to increase the load, blows nice and cold.
So I think my pack is close to the rated 45ah.
30ah should get me to work and back if I for some reason couldn't charge at work.
Should have a useful range of around 40-45 miles. 80-90 miles when I get the other two groups put in.
Ran the AC while testing to increase the load, blows nice and cold.
yopappamon
10 kW
About 4.5 hours to recharge on 230v 15 amps
Are you planning to use the cooling passages on the battery?
yopappamon
10 kW
fechter said:
No, I have no plans for cooling. At most, I might put a fan on the openings. The data I've seen, I shouldn't have a heat problem on what I'm drawing.
dnmun
1 PW
the volt also uses a heater for the coolant around the cells to keep the cells warm enuff in winter that they can be used. charging frozen cells is not good. it seems easy enuff to have a low pressure coolant loop and worth the effort versus risks. that could affect balancing too if the ends are a different temperature from the middle.
Similar threads
