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IPS 191 Lhotz Battery Upgrade


Slaughthammer
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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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Edited by Slaughthammer
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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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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...

@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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Update: just finished another 3,75 km of cruising around on the same charge, until under voltage alarm kicked in again. I was cruisig harder than earlier today, lots of turns, hard acceleration etc.

Added these results in the previous post

Edited by Slaughthammer
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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.

Edited by mrelwood
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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.

Edited by Slaughthammer
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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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