Topping / Charging with 300mA Ebay-LED-powe-supply

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Frolle
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Mentioned in a thread earlier I found cheap power supplies on Ebay to lift a "to discharged" battery to a level where the bulult in one can kick in.

I have now tested on a Vectrix with a broken built-in-charger.

I did put two of those in series (30-90V 300mA):
30-90v.jpg

I have about +20°C in the garage and the pack held 120V when connecting the chargers.

Now after (about) six days I can read 141V, and the pack shows +27°C.

24h x 6d x 130V x 0,3A = 5,6kWh went in to the pack.

Obviously the pack started to develop some heat, and I have no active cooling. But the top of the battery housing is dismounted.

Future plan is to use two of those chargers to equalize the pack over weekends, or when the temperature allows it without active cooling.

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ofx210p
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

Thats very interesting - can you post more about the part number / specs of the LED power supply

Cheers

Chris

Frolle
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

Search Ebay for "30-90v" and you find it.

Did more tests:

Have not used the bike since previous charge to 141V & +27°C.

When connecting chargers/supplies:
139V +17°C

12h later I interrupted at:
142V +22°C

Power added to pack: 0,5 kWh.

So I assume the pack is 100% charged since the pack starts developing heat (no active cooling).
Could probably be connected forever if the fans where spinning.

I also realize lower charging current means lower target Voltage, since those 300mA will probably never be able to rise the voltage to 154V.

I assume I now have a fully equalized pack...? Please comment!

Mik
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

24h x 6.5 x 0.3A = 46.8Ah

The battery should be full and equalised, but it loses a substantial percentage of it's charge in the first day due to self-discharge.

It will also take about 3-5 full cycles to regain it's capacity and "Ooohhmpfff".

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CO2
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

I think to cell nimh full, we need more than 100%....

Mik
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

CO2 wrote:

I think to cell nimh full, we need more than 100%....

24h x 6.5 x 0.3A = 46.8Ah

46.8 Ah / 30Ah (nominal) = 1.56 = 156% full

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CO2
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

Mik wrote:
CO2 wrote:

I think to cell nimh full, we need more than 100%....

24h x 6.5 x 0.3A = 46.8Ah

46.8 Ah / 30Ah (nominal) = 1.56 = 156% full

I was thinking about 140%...do you think 1,56v is sure?

Mik
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

CO2 wrote:
Mik wrote:
CO2 wrote:

I think to cell nimh full, we need more than 100%....

24h x 6.5 x 0.3A = 46.8Ah

46.8 Ah / 30Ah (nominal) = 1.56 = 156% full

I was thinking about 140%...do you think 1,56v is sure?

156% is more than 140%, so yes.

But, with very slow charge rates (0.3A = C/100) the charging is less efficient, so it might not be full. However, when the battery is warming up, it should be full.

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CO2
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Re: Topping / Charging with 300mA Ebay-LED-powe-supply

What is warming for you? 25.ºC in cell when we have 20.ºc exterior?

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