A high power full pack balancer cycler

[retepsnikrep]

A high power complete cycler may well be an option now if you have a high power bench charger and discharger. And it might actually be possible to use the OEM BCM to do the monitoring and the BCM interceptor or a variation of it to do the controlling by looking at the BATTSCI data bytes.

So you have a pack on the bench with control boards and bcm/mcm fitted as normal, you attach the high power charger/discharger to the grid charger points on the ima board along with a 350ma final balance grid charger. You plug the BCM device into the BCM which powers the BCM so it can do the monitoring. The BCM device watches the BATTSCI signals and controls the chargers/discharger/fans etc as appropriate. A nice little display could show us the BCM data, current, voltage, temp etc which is all now available.

I like this idea and will have a look into it.

I have a 3kw charger which can output 15-18A at reqd voltage. And a discharger can be made using a 220v/110v immersion heater and a bucket of water.

Another project looms

[Mike Dabrowski 2000]

On the Insight pack, Rons system of cycling on a subpack by subpack level assures that each subpack gets fully cycled and the AH capacity and self discharge of each can be determined as a measure of cell condition.

Doing the whole pack as far as I can see will stop the discharge at the first subpack to reach empty so the better cells are not getting fully cycled. The BATTSCI as far as I know does not report the individual tap voltages, so IMHO true balancing cannot take place without a way to safely fully discharge all 20 subpacks?

I am pursuing a similar project for the Prius packs,with the goal of being able to use the packs for PHEV booster packs,while using the built in CAN communication to fully monitor the charge and discharge.
The Prius BCM can show the voltage on each 12 cells, (tap points), as well as delta V between taps, overall SOC, temp, and many other parameters.

[retepsnikrep]

I agree initially during cycling the lowest subpack will stop the discharge, but I don't see that as a major issue because after a few cycles hopefully the weaker cells will have started to come back up in capacity so the discharges will lengthen progressively as the cycles continue. I agree it's not ideal but it's a lot less bother for me with only a couple of connections to make and not so much dissasembly. I just haven't got time to do the full pack cycling at the individual subpack level routinely. If I can speed up the process for me then great. It's just another option.

I look forward to your Can results.

[E27006]

A high power complete cycler may well be an option now if you have a high power bench charger and discharger. And it might actually be possible to use the OEM BCM to do the monitoring and the BCM interceptor or a variation of it to do the controlling by looking at the BATTSCI data bytes.

So you have a pack on the bench with control boards and bcm/mcm fitted as normal, you attach the high power charger/discharger to the grid charger points on the ima board along with a 350ma final balance grid charger. You plug the BCM device into the BCM which powers the BCM so it can do the monitoring. The BCM device watches the BATTSCI signals and controls the chargers/discharger/fans etc as appropriate. A nice little display could show us the BCM data, current, voltage, temp etc which is all now available.

I like this idea and will have a look into it.

I have a 3kw charger which can output 15-18A at reqd voltage. And a discharger can be made using a 220v/110v immersion heater and a bucket of water



This is brillant incisive thinking! Utilising of the Cars technical resources.


We could charge on the Bench or with the pack still in the Car too

Do you think the BCM could be powered independently by a seperate supply ( eg relay in the loom )?
The BCM interceptor could read and monitor the 12 byte digital messages on Battsci for PTC temperature, pack voltage etc and run the show as required.

Those 350mA CC supplies from Meanwell work out at £45, I found an IC the L200 Current/Voltage regulator up to 2Amps which cost less than £4.

The data/app notes are in the link, fig 26 in the notes show a high output voltage constant current circuit.


Link:

http://www.st.com/stonline/products/...re/ds/1318.pdf

[Mike Dabrowski 2000]

E27006,
The regulator is a good find, and could do the job, we need to consider the cost of the isolated AC to DC power supply required to power it as a charger, and it needs to put in a safe box.


The meanwell starts to look like a better deal if you consider all of that, and it has a wider output voltage swing while maintaining the CC.

[retepsnikrep]

I bought 10 of the 350ma cc supplies in one go and they were about £15.00 or something each i think. I actually need to order 3 more if you want one malcolm I'll add an extra one.

I have mentioned and built an IMA cycler in another thread which does the charging up/down using the ima motor/engine and all the in car resources. It's a very specialised cut down IMA control unit which basically forces assist and regen for several full battery cycles. It needs more work but could be interesting.

The on the bench high power pack cycler is more intruiging and useful for me, I don't think that's an in car option as the battry will have to come out anyway to make some decent connections for the high current charger/discharger. No 1/4" spade connectors for this project!

Plus once the cycler has done it's stuff the battery may then have to come apart for more testing or cell replacement. I don't see it as a project for the masses at all either. Ron, Mike and you Malcom could be the only one's interested in a pcb.

My 236,000 mile test car has P1449 issues and i can't be bothered taking the battery out and cycling it at the moment so i use the grid charger to keep it going, and am planning on a cheapo lithium upgrade instead. Probably using either headway or lifebatt 8ah cells.

I don't think the L200 reg is an option we need an isolated supply and the meanwell ones work very well.

[E27006]

If they are abt £15 then they must have been overcharged. I paid £47 including delivery.

Their Sales Office is located in Aldershot.

If Meanwell supplies are only £15 each then the L200 is clearly a non runner .

I wired my pack for in-situ balancing, 4 wireson the Junction board in total, also for two of the sticks ran wires off each end to external points to facilitate Robitronics cycling, the wires were soldered in place to the stick bolts and testing the joints they are very strong

Yes please, I'd like a spare supply