105 Nimh cells in pack

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Sugarstorm
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Last seen: 4 years 2 months ago
Joined: Wednesday, February 22, 2012 - 09:37
Points: 49
105 Nimh cells in pack

Hi you all,

My V is now at 64.200kms and the current pack has 42.000kms. And it shows...
The range is down to 30-50 kms, depending on the throtle usage.
I have access to Nimh cells and I thought that if you can shunt a dead cell and leave 101 working, why can't you place, let's say, 3 extra cells in the pack and bring the total to 105?
Has anyone tried it before? Is there enough space for them on top of the front row?
105*1.4v=147v, wich is what my charger asks the bike everyday.
But at the end of a charge, as soon as I disconnect the charger, the voltage drops to 141/142v and after a few meters is down to 138/139v.
Would the voltage hold better with 105 cells?
Wouldn't the 105 cells be safer both at high and low voltage limits?
Would the charger work OK?
My ride to work is 30 kms, and I have a big climb at the end of the return. In the climb the voltage drops easily to values under 120v under load, and I don't like to stress the pack each and everyday. But it happens.
This might be a cheap and easy fix. If it works.
Let the discussion begin!

Vectrixuwe
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Last seen: 4 years 11 months ago
Joined: Thursday, January 3, 2013 - 10:51
Points: 31
Re: 105 Nimh cells in pack

Hi Sugar, at normaly your V. need 5 cells more. The peak of the charger is 159 Volt. With 107 cells you can switch of all limits from the charger. That is the best for the NiMh, the riding and the range. So you can ride 50 km with more than 138 V. Normaly the voltage is 150v, 107*1,4. when charging it goes from 152 to 159, so every cell has 1,4 to 1,49 Volt.
Have a good ride
Uwe

Mik
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Last seen: 5 years 8 months ago
Joined: Tuesday, December 11, 2007 - 15:27
Points: 3739
Re: 105 Nimh cells in pack

I think it is a bad idea, because cells will reverse when the MC allows the usual low voltage cutoffs to occur.

Less cells in pack will cause overcharging.

More cells in pack will cause over-discharging.

Mik

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Todd
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Last seen: 8 years 1 month ago
Joined: Wednesday, March 24, 2010 - 00:04
Points: 64
Re: 105 Nimh cells in pack

Sugar,

I was getting low voltage and reduced range as well. Upon disassembling the pack I found 4 dead cells. Not low, dead.

I replaced the 4 dead cells along with any cells that showed bulging. Range went up from about 20km to 35km. An improvement but I was expecting better. I have since bought and RC charger and started using it to test sub-pack capacity.

Before thinking of adding to your pack I would check to make sure you don't have a few "bad apples".

VECTRIX_MOBILE
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Last seen: 8 years 1 month ago
Joined: Friday, October 18, 2013 - 06:38
Points: 2
Re: 105 Nimh cells in pack

I just installed a pack of 50 Ah. I did a driving test and this is the result:

TOTAL RUN 126 km as follow
36 km highway at 85kmh
69 km statal way between 60kmh and 70 kmh
21 km city street between 30kmh and 50 kmh

total battery charge of 5,1 kwh in 5 hours
Total cost (Italy) 2,1 €
cost per KM 0,008€ !!!!

Rob_mobile

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