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IPS 191 Lhotz Battery Upgrade


Slaughthammer

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As I mentioned earlier, and always raising interest, I am currently upgrading my IPS 191 "Lhotz" 340 Wh with an additional 16s pack of 18650 cells. So here is some documentary about this mod, so anyone can consider if it's worth it.

Some details: I use Samsung SDI INR18650-30Q cells, as they are available quite cheap around here and had some good tests, beeing able to output 20A cont. while beeing rated by Samsung for 15A. However, turns out that even at 20A this cell can compete with the infamous LG HG2. Rated at 3 Ah this gives me 3*3,7*16=177,6 Wh additional capacity, making my Lhotz a roughly 520 Wh wheel! As these 30Qs have an internal resistance of only 18 mOhms, as opposed to 35 mOhms of the stock Panasonics IPS uses, this should nearly half the voltage drop under load, giving me either further additional range, or at the same range less limitations due to low voltage.

Well not gonna bore you any longer with this, here are the pics. First, starting point:

Foto-0348.jpg

Foto-0352.jpgFoto-0350.jpg

(the beeper was moved up prior to taking this photo, otherwise this is how the internals looked)

How do we get 16 18650s in there? First idea:

SAM_1253.jpgSAM_1255.jpg

Fits comfortably in there, but wiring would be a real mess. So I came up with this:SAM_1258.jpg

Nice and thight, and all the cells relatively compact together. I will not document on how to build the actual packs from the cells, this has been documente often enough on the internet I you want to do this, just keep in mind there is no space at disposal, just make those packs as tight and small as possible.

Packs assembled and test fitted in:SAM_1284.jpg

As you will have guessed, I will hook the new pack to the BMS of the wheel, thus all the thin white cables. In the bottom left corner you can see the connectors and how I dasy chained them, so i can plug both batteries to the BMS. I will do the same with the XT60 connector, so I don't have to touch any of the origianl wiring, besindes some relocation. Thus I can always extract my additional battery without much fuzz. As the packs are positioned tight against the metal controlboard box, I added an extra rub protection cardboard layer inside the shrinkwrap of the packs. But there won't be much rubbing here, it's a really thight fit!

I should further mention that the sprew posts in the places where the new battery sits need to be removed.

Left to do: finish the connections, fix all the wires in place, fasten the batteries,

 

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I would be interested how you "hook" this new 16s system to the existing BMS....and hope that that BMS can cope with an additional 16 cells?!

if you are not sure about that question  Chris from 1Radwerkstatt about that....as you are the first to try that as far as I know

no offense meant here, but the BMS is designed to deal with a certain amount of voltage for balancing...a16s2p system....I don't know if it can automatically handle 1/3 more?

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Balancing gets easier the more parallel cells you have, as differences tend to even each other out. And even if they don't, balancing will just take longer, as voltages stay exacly the same, only capacity is increased.

As for how i hook it ups, its quite easy. Just put all the balancing wires in parallel to the main battery. Thus each single new cell is paralleled to the two cells already there. Electrically this is just one single 16s3p pack, seperation is just physical. Of course I will monitor balancing in the future and if the BMS can't handle it, I can still charge and balance each batterypack iniviually. But I don't expect any problems. I will post some pics of the wiring later on.

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Good Job then!

i got the idea, that for example one "circle" Is monitoring 2 cells and get them to a full charge of 8,4 volt...or balance them to that ....

when now not 8,4, but 12,6 for 3 cells is the right amount of what has to be there in the end....I would have guess that at least a firmware upgrade of the BMS is needed....

but in the end you will see what happends ;-)

like is said, not meant as offense...more than an "take attention"....

chris @1RadWerkstatt? Can you give as an insight?

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16 minutes ago, KingSong69 said:

i got the idea, that for example one "circle" Is monitoring 2 cells and get them to a full charge of 8,4 volt...or balance them to that ....

when now not 8,4, but 12,6 for 3 cells is the right amount of what has to be there in the end....I would have guess that at least a firmware upgrade of the BMS is needed....

Thats totally not how lithium battery packs work... I suggest you do your own research if you're interessted in the matter :)

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I'm calling this Mod finished now, wheel is back together and everything is working just fine.

SAM_1300 (2).jpg

Complete batterypack with all connectors.

SAM_1301.jpg

Detailshot on connectors. I put one male and female of each on there so I can dasy chain the two batterypacks.

SAM_1303.jpg

Everything back in the wheel, but now arranged properly and everything glued down. I thought what works for IPS will work for me, gatherd the hotglue gun and hotsnotted everything down until nothing will move too much.

SAM_1304.jpgSAM_1306.jpg

further details of wiring. Quite a spagetti monster. I really hope i don't have to replace the tire anytime soon...

Range test must wait until the ice has molten from the roads. Checking forecast... maybe end of next week.

Aftermath: This mod cost me around 150€, the wheel gets a little under a kilogramm heavier. The connectors for the balancing wires were a PITA to find anywhere (had to ship them from china) and are called JST 2.5 SM connectors, needed in 7 and 11 pin variant. (took me quite a bit of researching just finding out how those things are called). If you want to do this mod as well, be kind on your nerves and get a proper crimping tool for those connectors, and use no larger than 0,3mm² silicone insulated wire. Of course, for the main leads you need something like 2,5mm², but if you can't figure that out yourself, you should probably not mess around with EUC internals. And be warned, if any of those connections break, it might cause a faceplant, or even worse, burn down your house!

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2 hours ago, Slaughthammer said:

I'm calling this Mod finished now, wheel is back together and everything is working just fine.

SAM_1300 (2).jpg

Complete batterypack with all connectors.

SAM_1301.jpg

Detailshot on connectors. I put one male and female of each on there so I can dasy chain the two batterypacks.

SAM_1303.jpg

Everything back in the wheel, but now arranged properly and everything glued down. I thought what works for IPS will work for me, gatherd the hotglue gun and hotsnotted everything down until nothing will move too much.

SAM_1304.jpgSAM_1306.jpg

further details of wiring. Quite a spagetti monster. I really hope i don't have to replace the tire anytime soon...

Range test must wait until the ice has molten from the roads. Checking forecast... maybe end of next week.

Aftermath: This mod cost me around 150€, the wheel gets a little under a kilogramm heavier. The connectors for the balancing wires were a PITA to find anywhere (had to ship them from china) and are called JST 2.5 SM connectores, needed in 7 and 11 pin variant. (took me quite a bit of researching just finding out how those things are called). If you want to do this mot as well, be kind on your nerves and get a proper crimping tool for those connectors, and use no larger than 0,3mm² silicone insulated wire. Of course, for the main leads you need something like 2,5mm², but if you can't figure that out yourself, you should probably not mess around with EUC internals. And be warned, if any of those connections break, it might cause a faceplant, or even worse, burn down your house!

Great job, but please do check it carefully and again and again, make sure everything is ok.

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12 hours ago, rayna903 said:

Great job, but please do check it carefully and again and again, make sure everything is ok.

Be assured that I double- and tipplechecked everything thoroughly before anything was plugged in. I understand the dangers caused by wrongly wired lithium batteries, and I don't want to burn down my house ;)

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  • 3 weeks later...

So, finally the weather was reasonably nice, so i could do some range testing. Conditions: partly sunny wheather, ~5 kn of wind, 7°C. The landscape around here is rather flat, with some slight waves, elevation differences around 20 m. cruising speed was mostly around 20 km/h. Rider weight with clothes: ~85kg. Tire pressure 3,5 bar. I took notes during the ride of distance and battery status. All readings taken immediately after dismounting if not stated otherwise. Summary:

Rangetest.thumb.PNG.6b11028d56441de98b3a2f756cc295d6.PNG

Some comments on the measuring points and distances travelled:

  • 5,93 km: starting of with a long flat incline, 3 km, then mostly flat. Mosly paved bikeways, some gravel trials. Last 1,5 km going through a town.
  • 8,03 km: mostly slow driving around town, many pedestrians
  • 11,52 km: nice level cruising on mostly asphalt bikeways. No wind.
  • 14,73 km: some rougher trials, some inclines and declines. Went groceries shopping, so after this stop my backpack was ~4 kg heavier. Second voltage reading after shopping, roughly 20 min.
  • 17,08 km: Undervoltage alarm kicked in. Luckily by then I had reached the top of the "wave" in the landscape. Also the wind hat turned and picked up, so I had some headwind. Again, some better and some rougher trials, even grass and a little mud now and then.
  • 19,87 km: Back home. During the decline the battery recoverd to 35%. The rest was mostly level, and less wind than before. Still some juice left, so I will call this 20 km range.
  • 23,65 km: some hours later I wanted to find out how much juice there actually was left in the battery. So I rode around the streets until the low voltage warning kicked in again. I rode more agressive than before, many corners, hard acceleration etc.

I am pretty statisfied with this outcome. 23+ km of 20 kph cruising is what I hoped for, but more than I dared to expect. Before the battery extension I could do about 12-13 km of 20 kph cruising. So my assumptions at the beginning regarding less voltage drop due to more cells in parallel and especially cells with lower internal resistance seems not to be entirely wrong. I checked the balancing now, after discharging, and the cells are all within a 10 mV span, so I'd call that rather good. At least that's how it was before I added the batteries. The rearranged wires seem to like their new places, none has moved anywhere it shouldn't have.

Here is an impression of the rougher trials. The wheel handles this perfectly.

 

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@Slaughthammer, nice set of data, appreciated. Am I getting the numbers correct that you get a 20km range out of a nominal 520Wh battery? Does that reflect the efficiency of the Lhotz reasonably well? It would be 26Wh/km or 3.8km/100Wh for a single battery charge.

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I didn't squeeze the battery until it's completely empty. As I don't have a charge doctor right here, I can't measure exactly, how much energy I used. By now, the Battery has recovered to 3,61V/cell, so there's definately plenty of juice left. However, the BMS won't allow to discharge below 3,4V/cell. The cells are rated for discharge to 2,5V. I'd guess that I used no more than 400 Wh, so that would make it more like 20 Wh/km for cruising around 20 kph.

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  • 3 months later...

I'm doing this exact same mod right now, as all the parts have finally arrived. A quick question though to Slaughthammer:

The balancing connectors also have one black and two red wires. I measure 0V between the black and the main negative (thick black), as well as 0V between both reds and the main positive (thick red). Just making sure, are they just doubles for the main + and -?

I can't figure out why they are there, as the BMS gets the main + and - as well.

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Wondered about that too. But then I realised that all ballancing connectors I came across are made this way and stopped bothering.

I think between the two red wires there might be some sort of PTC as a means of temerature controlling for the battery. If they are not connected the battery won't charge. I only connected one of them to my additional battery as not to sabbotage what ever protection there might be.

My wheel still runs fine with this mod, it has done more than 300 km since the mod.

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Thanks for posting @Slaughthammer, very interesting. I accidentally killed my LHOTZ a month or so ago and have just finished repairing it. Today was the first real ride after putting it all back together so i was a little nervous for the first my or so, just in case my workmanship wasn't quite good enough. 

IPS sent me a new control board and a new battery but inevitably in the year and a bit since mine was made the connectors and design of some bits have changed so I wasn't able to hook up the lighting control board but other than that all is working fine. It did occur to me when i had it all in bits that there was space in the shell for more batteries. I wondered if you could get two 340 packs side by side but there isn't quite enough room and the cable management as they come over the top of the housing to the control board side would be tight. 

 

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3 hours ago, nute said:

I wondered if you could get two 340 packs side by side

Early on I built extended wooden leg supports for my Lhotz reminicent of an IPS "Tank" 121.

IMG_1152.JPG

My wild idea now was to modify the actual case to be the support, and to fit another additional 16 cells and the cabling in the created space. That would total almost 700Wh (16s4p).

Maybe later, now I can't wait to get just the "Slaughthammer mod" up and running. Almost done, I just barely run out of the spaghetti.

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On 5/22/2017 at 11:29 PM, Slaughthammer said:

And yes, it's astonishing how quickly the wires are used up...

I only could source a slightly thicker one locally, but got it to fit.

Having a problem though. The new battery is connected, original is not, as it is of a different charge. Connected the charger, but it only blinks red and immediately turns to green. So it won't charge.

I'm suspecting the last pin on the 11-pin connector we talked about earlier. I guess it is needed for the charge to happen. I think I'll jumper it just to charge the voltages identical, then connect the original battery as well.

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5 minutes ago, mrelwood said:

 

I'm suspecting the last pin on the 11-pin connector we talked about earlier. I guess it is needed for the charge to happen. I think I'll jumper it just to charge the voltages identical, then connect the original battery as well.

You're suspecting correctly, and that's exactly what I did. The voltage difference between the packs should be below 0,5V when you connect them.

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Yes, that was it! I made a female connector with just a jumper wire between the last pins, and connected it where the original battery will be connected. The new battery now charges via the Lhotz BMS!

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10 minutes ago, Slaughthammer said:

You're suspecting correctly, and that's exactly what I did. The voltage difference between the packs should be below 0,5V when you connect them.

Thanks! I was aiming a bit closer, but it might be difficult. Very good to know.

Should I connect the balancing connectors before the main power connector?

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I'd connect the XT60s first, as they are better capable of handling  the currents. At 0,5 V difference, balancing current beween the packs should not exceed 1A. In that case it really doesn't matter what's connected first, but if something goes wrong... Or maybe it's better to connect tha balancing wires first, because if something goes wrong, those tiny wires will act as a fuse?

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