48v 11.6AH Battery high voltage Cut-off

Kisho

Just Joined
Feb 19, 2018
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25
London
Hi All,

My first post in this forum!!! My name is Kisho and nice to e-meet you all!! Hope you are doing great!!!

I am having trouble with my e-bike battery. The power completely cuts out under a medium-high load. The LCD goes error 006 (low voltage error) and an off/on is required to get going again. The cut out happens very fast around 450w (on LCD). The bike has been going well for about 6 years and has had a controller upgrade to Greentime 500w-600w 30Amp - 48V - 12 MOSFET controller with LCD (had for 7 Months).

Specs: Greentime 30Amp - 48V - 12 MOSFET 500-600w Wiring Controller, Brushless 500W motor (motor wires upgraded), Yosepower 48v 11.6AH Battery (had for 2 years) Battery Link for information.

So, I have 3 other batteries all of the similar specs but from different providers (2x eclipse bikes, 1x eBay) which are about 3 years old now but still strong to handle the full load from the motor without cutting out (but I take them gently now as they are around 80% capacity). But so far states that the motor, controller are running fine (still checked either way to make sure).

So, after 2 attempts of full charge and the battery cutting out while riding, I decided to do a battery test with a constant 75w being drawn out to find the LVC which was around 46-47v. From that, I decided to disassemble the battery to see if any wires or connectors may raise the issue but they all seem to be fine (one image looks like a cell leak but I believe it from the adhesive foam padding). Measured voltage pack directly from the battery which was 54.06v and same on the discharge port that matched.


tired getting measurement of each cell but I think it balances out in series due to the metal plates, but I measured across all the pins on the BMS which the results were as below:
  • 4.17
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.16
  • 4.13

Sorry for the long thread but I hope to clarify all the checks I've done and hope I could hear some advice from you soon :)

many thanks
Kisho
 

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vfr400

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Jun 12, 2011
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Those cells are only rated at 2.75A continuous, which is 11A continuous for you whole 13S4P pack. With a 30A controller, you've been over-loading them. so they've worn out quicker than normal and they've become saggy. For a 30A controller, you should get a battery with cells that can give at least 7.5A continuous.

When you plan an ebike system, you need to make sure that the motor, controller and battery all have suitable current ratings.
 

Kisho

Just Joined
Feb 19, 2018
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25
London
Thanks for the reply, So my Previous controller had a blown Mosfet that had a spec of 48v/500w 22amps max current that I believe was perfectly suitable for the battery as kept going for 1.4 years until I upgraded the controller only making this battery last for 6 months.

I also have another Ebike build rated 48v/500w at 23amps max current controller with a 500w motor and also cuts out on the same battery on a full charge. Could this mean the battery pack is just destroyed or BMS might be faulty even though the voltage readings directly from the battery and BMS output matches
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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When batteries become worn out, they sag more and more, i.e. the voltage reduces when you use a lot of power. eventually the sag gets so bad that you hit the low voltage cut-off (LVC) whenever you demand maximum power. Uffectively, that reduces the range that you can get from it. The further you go in your journey, the lower the base voltage, and the more likely is the sag to hit the LVC. You can still use the battery as long as you work it with less current. With a KT controller, you can turn down the current in the settings.

The harder you use your battery, the quicker it'll wear out, though some types of cell are designed for more current than others. You should always be mindful of what cells you have . Yours would have been fine at 15 amps, above that, they'll work. I don't think there's a boarder for how far you can go as long as you don't go over the BMS limit, but it's sure to be a rule that the further you go, the quicker your battery is going to get worn out, and I think that when you go over the 8 amps per cell maximum, they're not going to last very long at all.

Batteries don't last forever regardless of what you do, except maybe if you take it off the bike and keep it in a fridge at 3.6v per cell. Use the opportunity to get a better one if you can afford it. every year, they improve about 10%, so today's batteries should be 77% better than the one you bought 6 years ago.
 
Last edited:

Nealh

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Aug 7, 2014
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The battery is knackered for high power use.
The 29e cells are past their best and are only useful on low power use now.

I have two 29e battery packs in the same state. I over amped them with too much current and they lost capacity, on high power they are useless but are ok on PAS 1. At a mere 2.6a draw they are useful for abut 40 miles but up the current/pas level then they are only good for half that in PAS 2 and even less in PAS 3.
Simply put any 29e cell in 4p or 5p configuration needs to be used carefully with current, that said they are still a very good cell with high capacity retention if used properly.

As in #1 the balance is good barring the last group, voltage though doesn't mean the cells capacity is likewise. Just because voltage is good it doesn't take into account any ageing of the cells, if one was able to capacity test the cells then the IR would show up as being high at probably more then 75/80 ohms per cell. An indication of ageing.
I have some cells (various) at 75 - 125 ohms which are only good for flash lights, if I'm lucky I might get about 1 hours use before the light power noticeably fades.
 
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Kisho

Just Joined
Feb 19, 2018
4
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25
London
Thanks for the info both, and yes as to how you describe the PAS I'm achieving similar results also. Okay, I'll look into investing in a new battery around the end of January. Just deciding between Yose Power 20AH or EM3ev 48v 17.5AH (which costs more but seems to have a better manufacturing quality).

Yose Power 20AH
EM3ev 17.5AH

Checking from the specs, I believe both products are suitable for my e-bike system setup?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
19,995
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Em3ev is China/HK, vat and other duty will likely be added now as you will be the sole importer after tomorrow and might be a good test case for new trading rules.
The Yose batteries give scant details of cell brand.

Look to see what ebikebatteries.co.uk have and also enerpower in Germany.
 

Kisho

Just Joined
Feb 19, 2018
4
0
25
London
Thanks! I'll have a look around the different batteries and think about what would be the best choice for me by the end of January. I'll pop back with the results I've chosen hopefully then.
 

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