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Discussion Starter #1
Hona Fit EV batteries from Greentec Auto
3 packs, 72 cells
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Green electrical tape to hopefully protect from shorting the batteries. This photo is just trying to see where they fit with foam blocks.

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I determined things would be easier if I had some extra room.


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This gets you about 2 exra inches.

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Early mockup of supports. For some reason I didn't realize the forward bolts for the stock battery lined up with the ones on the bar.

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Later I switched the layout. This is another mockup.
 

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Engine-Off-Coast
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Discussion Starter #2 (Edited)
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Building an aluminum frame like this is pretty hard. Especially since I don't have a drill press. Advice to anyone who follows this --see the smaller ¾" square tube, don't put that there. If you use it put it further towards the rear of the car or better yet just use a ⅛" x ¾" strip held in by L brackets. This one is too thick and poorly positioned so it blocks the ability to put both BCM and MCM under the batteries. There's space for one computer, but not both, so I will probably move it or replace it.

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This is enough to support and bolt in the back two packs. Another 1 inch tube should be put along the front-side (front of car) to support the other side of the LTO packs.


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This gets you to here. Notice the sideways pack is not able to be supoorted yet.

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Putting short sideways bars like the one seen above will give it something to rest on. I only did this for the left side, I might do it also for the right side if I get access to a TIG welder. The little one that's there in the photo uses a factory bolt hole on the 1 inch rail that's already in the car.

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Oh I also cleaned up the hole. It has black tubing stuff slit down the middle and zip tied to the opening edges. I could have gone a little bit further to the right with the opening, but this here was barely enough.
 

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Discussion Starter #3
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I ran into trouble with the junction board, this is where I am stuck right now. Above photo shows that I was trying to copy what @jime did with his junction board. I've got this wire for example going to the aluminum bus bar but I pushed it in a bit away from the battery side of the opening. This one worked out really well.


But the next photo...

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... shows I had trouble bending the bus bar for the positive terminal. The metal fatigued and broke.

So I have some questions about current sensors!

  • This is a hall effect sensor right?
  • I am guessing the conductor carrying current through the centre of the sensor has to be positioned exactly in the centre of it for it to get an accurate reading, is that right?
  • Does the conductor material matter?
  • I am fortunate that I have 2 extra junction boards, so I can pull another bus bar off one of them, but would it be possible to just put one of my big green current carrying wires (as seen in top photo of this post) through the sensor, or would the reading be miscalibrated?
Also, now I am afraid of damaging another bus bar, so I am not sure what to do with regards to bending a replacement for this one away from the hole it ends in. Anyone have ideas on that?
 

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Nice progress and pics :)

1) Yes hall effect sensor.
2) Conductor does not have to be in dead center.
3) Conductor material does not matter.
4) Yes you can put your big wire through it.
 

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Discussion Starter #5
Wow thanks for the fast reply Peter, that's great news, I'll probably just put the wire right through there then.

Another question... in the photo with the green wire, the two terminals that are unpopulated go to the circuit breaker + giant fuse. Am I correct to assume it does NOT matter which of those two gets the positive side and which gets the negative side of a couple wires in series from two of the sub packs?
 

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I strongly recommend keep the polarity the same as OEM.

1) The circuit breaker may have magnetic blowouts which are polarity sensitive.
2) Same as OEM means standardisation and less room for confusion later if you or someone else works on your car.

Note depending on your configuration and proposed BMS be careful where you put your pack break.

If you are using the BCM fooler? then it's not super critical but IMO try and split the pack in a similar fashion to the oem. 50/50 60/40 or whatever for safety.
 

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Discussion Starter #7
Okay, I'll keep it the same.

I haven't got the BCM fooler and interceptor in the mail yet. I might just build a fooler using resistors I have laying around and give the one I bought to a friend who may do an LTO conversion down the road.

I think I have to split it 66/33 which isn't the best, but I'll be putting some extra fuses in series, the same ones @Atheos used, so there will be 3 fuses total plus the circuit breaker.
 

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I would not add extra fuses. The OEM fuse is perfectly sufficient and well specced.

Extras will add more connections, failure points and resistance to the current path.

You could easily remove the connecting busbar from your central pack and have a 50/50 split.
 

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View attachment 83078

I ran into trouble with the junction board, this is where I am stuck right now. Above photo shows that I was trying to copy what @jime did with his junction board. I've got this wire for example going to the aluminum bus bar but I pushed it in a bit away from the battery side of the opening. This one worked out really well.
Good on you. You made the leap!

Yeah, that pack positive bus bar is very difficult to reshape, and Peter is certainly right that there are other ways around that. I had to eliminate one of the pack "middle" bus bars just because I could find no way to reshape it. I just rebent the cable terminal end and ran it through the hole to the other side.

You can gain about a 1/4" of space if you take a hacksaw and cut those circular parts of the junction board down to the base level, but given your layout you may not actually need the space. You can also gain lots of space on the left by moving the junction board way over. The danger is the ground potential dc-dc cover. You can clean up the brackets on the side of it, and use 1/16 thickness of some decent insulation board.

Peter has given you lots of good info. Please continue to post pictures and questions. And hurray for you :)
 

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Discussion Starter #11
Thanks everyone!

Here's what I ended up with for the junction board.

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I hope this looks okay. I don't like how that wire has to snake a lot but I tried to make the curves wide to put less stress on it.

Where the wires cross on the back there is a little bit of slack there, and a couple pieces of electrical tape as a buffer, but if it looks unsafe I can figure something else out.
 

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I'm late to the party, but as for your aluminum frame you could use aluminum brazing rod. I just discovered the stuff myself, and it's really easy to use and strong when done right.


If you can solder you can use this stuff. It's the same skill. Just using a propane torch.

FWIW, I have had aluminum that I couldn't heat well enough with one torch and had to use 2 torches. Aluminum really wicks away the heat and FAST!
 

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I think the cables crossing will be ok. You could use a wire tie around them where they cross to stabilize them and prevent chafing. Actually you are only looking at half of the battery voltage between the two, so the dual layers of wire insulation should be more than adequate. Maybe the fuse is in that half and would blow anyway? I think you positive wire is fine.
 

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Discussion Starter #14
Okay no photos right now, but I got everything hooked up and running. But I haven't got everything put back together properly because I don't have a permanent mounting solution for the BCM and MCM. Right now I still have that ¾" bar underneath the back two packs which is unfortunately placed and prevents me from getting BOTH computers under the packs. I can go in there and reposition it, but before I do that has anyone had success putting the computers underneath the tom mix bar in front of the IPU case? The BCM fooler can just have its leads extended back there somehow.

Regarding the junction board I have a foam block separating it from the DC/DC Converter, but maybe I can replace the foam with coroplast. Things are tight there. On the battery side of the junction board I have a thinner piece of foam and some coroplast keeping the fuse and negative leads away from the batteries.

Battery terminals -- anyone know a good terminal cover? Right now I've just got them covered in electrical tape again.

Driving:
I've never driven an Insight with a properly working battery before, so this was a new experience for me. I have OBDIIC&C so I was able to watch some things.

Voltage started at 165 (the packs were 55 each before installation) and then pretty quickly went down to about 161-163. I saw 40 amps assist and 40 amps regen at different times. I don't think voltage dropped below 160. I was trying to keep it charged though. I'm not sure like a good driving style to maintain the life of the battery pack. Voltage for example, is there a window I should aim for? Or am I overthinking things?

I don't have the thermistors set up properly, so the temp they gave was just cabin temp, but after driving for 45 minutes each of the batteries still felt cool to the touch.
 

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Fantastic! You're a inspiration.

Sam
 

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Lookin GOOD. I new you could do it. Now for the FUN part. TESTING.

Willie
 

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What a brilliant solution to connecting the cable-ends to the junction board. Can't wait to see your pics.
 

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Wow, you are quick;)
Okay no photos right now, but I got everything hooked up and running. But I haven't got everything put back together properly because I don't have a permanent mounting solution for the BCM and MCM. Right now I still have that ¾" bar underneath the back two packs which is unfortunately placed and prevents me from getting BOTH computers under the packs. I can go in there and reposition it, but before I do that has anyone had success putting the computers underneath the tom mix bar in front of the IPU case? The BCM fooler can just have its leads extended back there somehow.
Yes, there is room to mount the BCM/MCM under the tom mix bar. I made those measurements and experimented a bit with that myself. There is a thread somewhere. I personally feel that is better than putting them under the batteries because of future access. I attached them to the bulkhead, but that is also awkward. I think a thin hanger bracket attached to the bar itself is best. You want to drop them down about 4 inches from the bar so you gain a bit more room and don't have them rattling against the bulkhead. I take it you don't have room to set them on top of the batteries?

Regarding the junction board I have a foam block separating it from the DC/DC Converter, but maybe I can replace the foam with coroplast. Things are tight there. On the battery side of the junction board I have a thinner piece of foam and some coroplast keeping the fuse and negative leads away from the batteries.
Sheet ABS is cheap on eBay. If you eliminate the brackets on the dc-dc cover, you could just use some 3m double sided automotive trim tape to attach a sheet to the dc-dc.

Battery terminals -- anyone know a good terminal cover? Right now I've just got them covered in electrical tape again.
Look at thread here:
https://www.insightcentral.net/threads/lto-lithium-battery-conversion-thread.112370/page-26#post-1410839

posts #506&507. You will have to use an Xacto knife to cut some rubber away on the backside, because they are made for smaller terminals. There may be a larger cover which fits better?

Voltage started at 165 (the packs were 55 each before installation) and then pretty quickly went down to about 161-163. I saw 40 amps assist and 40 amps regen at different times. I don't think voltage dropped below 160. I was trying to keep it charged though. I'm not sure like a good driving style to maintain the life of the battery pack. Voltage for example, is there a window I should aim for? Or am I overthinking things?
No, not overthinking it at all. The 72 cell conversion doesn't stay adequately charged IMO. Somewhere in my conversion thread, Peter recommended adding a 1% resistor of about 10K in the pos. side of the fooler and at some other critical point. iirc, he was talking about two ganged potentiometers at the time, but later judged that not precise enough to be trouble free. I still haven't made the mod myself. Unfortunately, he says it will throw off the C&C reading of the pack voltage. I just grid charge mine every 6 mo or so. IMO, without BMS you want to confine cell range to 2.5>2V/cell. That works out to be a pack range of 180V>144V. The car will not regen above 176V, so don't panic like I did.

We are still learning how to manage the LTO packs. There are still some loose ends;)
 

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You were very quick. I'm doing it a step at a time, removing pack, do some work, putting back, etc.
How did you 'mount' the junction board? Does the DC-DC cooling system have access to the outside vent? What was your solution?
 

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Natalya, take a look at this thread:


Post #21. The bulkhead did fit with the BCM/MCM mounted in that location on the bulkhead, but getting access is difficult. I think it would work better if one made a bracket out of thin aluminum and somehow mounted it directly to the tom mix bar. Then, access would be available by simply removing the bulkhead. Good luck with it :)
 
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