Just installed my 2nd user enginer 4 kwh kit.

MIGHT WANT TO HOLD OFF ON THAT FOR A MINUTE.
Nothing against Paciffic ev, or Orion, if anything the MD teck sounds like a direct replacement and supposedly it works well too, not sure what it will cost you thou, I think what Sush has been doing is great, and it appears to have good results too, I don't own one so I can not comment much but one thing that I'm not too comfortable with, I believe it uses the same logic as the old Enginer BMS ( which is nothing but a lithium fry cooker ) difference is they set up a timer where the balancing cycle only kicks in every other week, and apparently that is enough to keep the pack in check.
I personally have an issue with that logic, just a preference I guess, I think it was a bad idea to begin with and there's no sense in polishing a turd, that's not to say it won't work, Sush is one of very few, actually the only one I know of involved with MDtech ( Enginer ), that tried and came up with a solution, so in that aspect plug and play considering your 220v mains, it's probably your best bet.
I have the same issue on my hands, I recently acquired a good used pack, and there is no way in hell I am plugging it in on the current setup, I chose to scratch everything and start over, it is too soon to say but I am working on a BMS alternative, if you are patient I'll update this thread with my results soon. It wont be plug and play, but I believe it to be better, due to a totally different logic, the right one in my opinion, but it's not ready yet, so I'll hold off on my comments till I see it working on my kit,

I do have a question for the forum thou, by what means does the original BMS16D terminate the discharge?
I believe there is a 2 wire connector between it and the converter, and I know this much that once LVC is hit the discharge is terminated, but if I am not mistaking the pack is plugged into the converter directly, so I am assuming the bms shorts the 2 wires to signal end of discharge, because I read that you can run the kit without the bms,
I am trying to figure out how the bms interfaces with the converter, so I can wire up my new BMS to do the same, does anybody know about this, I could not find any info so far

 

sounds interesting.

i have had a response from Sush already, and MD tech seems to have a new improved version of the BMS.
i may well buy one and really keep a very close eye on it and see how it performs.

my current batteries are pretty much toast too, so i have no problem in testing it on them.
i will need new batteries in the very near future, so if the BMS from MD tech isn't very good, all i will have lost is some $$.

i will keep my eyes on this thread and see what you come up with.

thanks again.

Jason

 

Typically it is only one or two cells that are damaged in a Verion 4 Enginer battery pack which uses the RFE battery cells encased in two separate metal boxes. You may only need to replace one cell. Because all 16 cells are connected in series, one overcharged cell reduces the overall pack capacity. Although the RFE cells are a real cow to replace.

 

yeah, my kit uses the RFE batteries in the two metal boxes.

i have not attempted to open the boxes, as i suspect they contain pouch type cells.
not something i could replace myself. i have already found a local supplier of batteries and gotten a quote.

got my quote from sush at plughybrid too.

$424 for the new BMS and all the interconnects and the screen. not including freight.
the MD tech BMS has different sockets on it, and sush has the required leads to connect it to the enginer kit and batteries.

jason

 

couple of things, the boxes are not so bad to service, 2007blueprius's's Library | Photobucket I tore mine to pieces, lighting is not the greatest in my kitchen but you'll get the idea.
on mine the #1 and #2 are toast, 3,4,5, not far behind, lord knows what kind of capacity in the rest., that's pretty much what the current system does.
as for testing the md tech bms on your current pack, I don't think it would make a difference, if the cells are that far gone, charge is still terminated as soon as first cell hits lvc, there is no charge controller for that mater, I think what sush done different is balancing every 2 weeks, but it's the same old way, bottom balance, that is the logic I don't care much for, it appears to work if you start with a good pack, it can keep them in check, but if yours have 2 -3 years of abuse on it , it won't make a difference, so bottom line don't be surprised if Sush's BMS wont make a diference, no BMS would make any difference at this point.
at the same time I believe RFE cells may be of some degree inferior quality, as in not as consistent, so they propb tend to go out of balance on their own, combine that with a bad BMS ............... puffffffffff.
one thought to consider is a different kind of batteries, I was on a budget so RFE had to do, I got as set that supposedly did not have much use, and I plugged it in once, just to try it, and it behave well.
As for my BMS I am almost done, problem is I am not too good with electronics, I ran some tests this morning before going to work and I messed up somewhere, just placed an order for a few parts I still needed and I guess, I have a few days to figure out where did I screw up, I hope I'll be charging sometimes next weekend.
I guess if you are afraid to open up the rfe packages, your best bet is to go with Sush's BMS, or any other for that matter ( I don't know much about them ) and a new (to you), good pack, than again they are toast already, what can you possibly do to make it worse, that's how I look at it.

 

i have been in contact with the local supplier / installer of these kits, and they tell me that they are now using different batteries. something called LNE ? with a claimed life of 5000 cycles to 80%.....

i think the biggest problem with the kit i have, is that i brought the car from a second hand car dealer, and the car sat on his lot for over 90 days, with very little to no battery maintenance, and the BMS was left connected to the pack.

that's what sent the pack off the cliff.

so my hope is that with these new batteries, and a new BMS (with careful manual balance monitoring) that i should have a system that works as advertised. i don't mind manually checking the balance of the pack once a every few days, and if required, i have the ability to use my high power 8S balance charger from my RC cars to balance charge the packs.

the packs have a standard JST-XH type balance tap on them, so hooking them up to a good RC charger is a very simple task. i have 2 RC chargers that can charge 8S packs at up to 40A and balance current is up to 1A per cell. they balance at the top of the charge cycle. i can manually set the cell voltages at say 3.550V per cell, and it will keep going until all cells are at that level. even if some cells get there sooner, the charger will bring the others in line, while not overcharging the others.

the price i got the car for, was cheap enough that i can spend a little on getting the parts required.
i will still watch this thread with interest to see your BMS.

Jason.

 

now I dont know much about the RC chargers but that is the right Ideea, It's pretty much what I am working on ( made a bit of encouraging progress tonite ) heck, if they are that powerfull and you allready have them than scratch the original charger bms, and off you go, on the discharge side the converter will kick off at 47v I think, if charged right and a decent quality cell pack you should be ok, guess you could still use the original bms as a cute real time display and lvc cut off, I'm now actually more curious about your RC setup, I thought about it but I did not think I could find something that powerfull, and most comercial bms's are rated at what? 70ma?, 120 if you're lucky and spend a lot of $, I never checked on the Orion, or Paciffic ev, sushes too for that mater, but in my eyes 70 ma will do exactly didly squat on 80 ah cells charged at say 15 amp, hook up youd chargers and give it a go, that's your best bet I recon, cheapest too, ( you allready have them
as for the batery sitting in the lot, that's not it, how these systems work is charge it till the first one puffs, discharge it till the first one cliff dives, and they sold it as plug and play, now imagine your average housewife that bought into the kit, and now picture her as the previous owner, guess what happened to your pack now, I joined the party a little too late and I read many threads regarding, but batery management, one popular hack was the cell log way but all that does is lower HVC, raise LVC levels, still no charge controll you no one sees a problem, keep cooking the cells and wonder why, now the manual balancing is not for me, I'll do it every now and again if I must, butevery couple days? I'd rather walk

 

i have just piad for some new batteries, and should be getting the new BMS paid for soon too.

the RC chargers i have are revolectrix cellpro powerlab8 chargers (i have 2) and they run from a mains DC power supply at 24V 42A, so i can charge at up to 20A per charger as they both share the power-supply. if i had a better supply, i could charge at 40A per charger. the supply is a Meanwell SE1000-24. not the cheapest things to buy, but they have lots of grunt for running modern highly demanding RC chargers.

each charger can charge up to 8S packs and up to 36AH capacity, so assuming im never 100% flat,
they should be able to do the job of balancing the packs if and when it becomes necessary.

the cells i have ordered are 40AH 3.2V cells (32 of them) so i intend to buddy cell them and run them as 2x 8S2P strings, and then series them before the converter to give me the 48V that's required.

i will use the new BMS and very closely monitor it, and balance charge using the RC gear if it becomes needed.
i will use the new BMS as the LVC during use, and closely monitor the charging process.

if i do have to do a full balance charge once a week, it's no big deal for me.
hopefully that will not become necessary. but as you said, i have most of the equipment already.
all i need to make up is a charger to Anderson connector. the batteries will have standardized 8S JST-XH type balance taps on them already, so they will plug straight into the RC chargers.

if i was going to go the RC charging setup route, i would buy a Meanwell RSP 1500-27 supply and an icharger 4010 duo, and make up a permanent enclosure to keep in the car. that way i don't have to take the charger out when i want to use it for my RC cars and boats etc.

the MW RSP 1500-27 can run to 56A 27V and the icharger can charge at up to 2000W per Chanel (it's a dual Chanel charger) i may well end up going with that setup. time will tell.

keep us updated with the progress on your BMS design.

i will update when i get he batteries and the BMS.

Jason.

 

I think it is much more important to charge all cells even every time than LVC, the converter has a 47v per pack LVC, in theory if all your cells are evenly matched and fully charged everytime, no one cell will ever hit LVC before the entire pack, individual cell LVC is more like a second degree of protection, as the pack ages and some cells may build up more internal resistance than others, or at least that is how I understood it, the enginer kit actually relies on individual cell LVC and HVC dis/charging, I don't see that as a proper way to go about it,
also keep in mind, the balance leads thickness, I'm now waiting on some parts, but in the mean time, I will be upgrading the original RFE leads, I am not sure those dinky ones can handle 1 amp bleed current, even the JST connectors, they look more like read only hardware, no current, I'm thinking 12 awg household extension cord wires, I'll be sure to post some pics when done, but all in all I would be more confortable charging with your RC chargers, just use the existing bms as an LVC protection, I believe the MD teck is set at 2.5v as well for that aspect is no different than what you have already, I don't know what the new pack is costing you but I would not have the original charger/bms setup anywhere near it, just my take on it, pretty much what you are describing I am tying to accomplish with this BMS of mine, it's more like a charge controller if anything, I honestly believe that if you start with a full balanced pack everytime it will go a long way, it's how it should be.

 

i hear you. im paying top dollar for those 32 new cells, and i am not going to plug them into the existing BMS.

supposedly the MD tech BMS has LVC set at 2.8V per cell, so it should be easier on the cells than the enginer one ever was. my biggest problem is now it looks like i may need a new converter too.... nothing wrong with the existing unit, but it may not plug into the MD tech BMS.....

as for the balance tap wires, they can and do handle 1A fine. been using them om my big ebike packs for a couple years with my 12S lipo powered bike, and there's no signs of trouble yet. i certainly wouldn't push more than 1A though.

also, been in talks via email with Sushil and the new BMS is supposed to be a really big improvement.

from my most recent email " The MD-Tech balancing trigger is beautiful thing to see in action. BMS accuracy is 0.002V balancing is triggered at a Hi to Lo cell delta of 0.020V bringing the delta to 0.010V"

if MD tech are offering a 2 year warranty on kits sold now, they must be confident that the new BMS is not going to kill cells.

i sent Sushil some pictures of my converter and im now waiting to see if it will work with the new BMS.

glyndwr,

the power supply isn't being used as the charger, it is simply feeding the RC chargers power.
they have a display that shows how much current is being drawn from the supply, as well as how much current is being fed into the batteries, and i can say with some confidence that the one i have certainly does not run at maximum load 100% of the time.

ive been using it for a few years now, and no trouble yet.
can't say that's the same for all of them though. only the one i have....(SE1000-24)

im really hoping i can make it work with the new BMS, as at this stage i will have just about replaced the entire kit...

Jason

 

2007blueprius, how are you progressing on the BMS idea ?

i have not a great hope that the MD tech BMS will work with my current converter.
Sushil advised i may need to buy a new one

i don't want to do that, because the current one is working.

i am still investigating BMS options. i never did hear from Pacific EV. funny way to do business.
ignore potential customer emails.....

seems their BMS would be ideal for me, but it also seems it will not work with 240V.
if it's just a mains relay controlling the charger, it would seem a fairly easy thing to swap out a relay rated for 240V...

the other option i have (not one i want to go with) is to use the MD tech BMS to charge and as a monitor,
but then MANUALLY turn the system off if a cell hits LVC.

im keen to hear about your solution.....

Jason.

 

that's kinda what i think i will have to end up doing....the cell logger route.

unless 2007blueprius can get the zephyr up and working.... (i found the thread on the ES, where im also a member)

if i could get the zephyr charge controller working with my new cells in place, that would be perfect.
but it's way beyond my skill level to build such a thing

Jason

 

If you get cellogs, it it worth the extra few bucks to get ones that will record data.

That way you can go back and review how the batteries act under load in real world conditions. Sometimes just looking at resting voltage does not give you enough info.

 

thought i would post an update now that i know what i am going to be doing.

the local supplier / installer of these kits has been next to useless.
also, im not having much luck with the MD tech BMS, so what i have decided to do is basically start over.

all i will be keeping is the DC-DC converter.
i will be replacing the batteries, BMS and charger from a OZ based EV parts supplier.

it will not be a cheap exercise, but the end result will be worth it im certain.
i will be running 32x 40AH Calb cells in a 16s2p configuration, with the EV parts shop's own design BMS, and a TCCH 16S 25A charger.

their BMS uses distributed cell modules to protect the cells, and it uses coulomb counting, along with pack voltage to determine SOC. it also has a built in relay capable of switching 80A at 48V, so it should be able to switch the DC-DC on and off no problems. it also has a charger interface, so it can turn the charger on and off.

i will be ordering the parts this week.
they should arrive in a week or 2 (they are coming from the other side of the country)
i am aiming for a january install.

pictures and progress reports will follow.

thanks to everyone here that helped me reach this decision.

Jason

 

Jason,
That sounds like a good plan.
Calbs are easy to configure and easily swapped.
And just about anything is better than some of the previous BMS options.

 

the total cost will be around $4,000 AU installed. not cheap, but i am using quality components, with decent battery management in place, so hopefully this will last many many years.

the install will happen in the first 2 weeks of January.
i will update (or start a new thread) when the install happens, and i will post results also.

the converter in the car now outputs around 15A at maximum, and drops off as the traction pack voltage rises.
i have the 5000W badged converter. it's probably more like 4000W though....
draw on the pack is reported as around 75A at maximum too.


Jason