[spdas]

Aloha, I can see a need for a charger that can go say 2v to 10vdc in 0.1v increments and have adjustable Amperage. Something for the bench but can also be taken out to the car to even up a cell or two.

What do you suggest that is accurate and inexpensive?

Would this work?

http://cgi.ebay.com/BK-Precision-16...533?pt=LH_DefaultDomain_0&hash=item2eb2b38ac5

thanks Francis

 

[GizmoEV]

Francis, That would work but you might be happier if you had one with a digital display. I've seen some go for less than the $100 being asked for on that one.

 

[spdas]

Aloha, advice taken. It would be hard to get a precise voltage with analog gauges. I was buying a 30v 5 amp then decided to find a 10a and finally bought this 20amp model for $209.00, (especially for lithium)

http://www.mastechpowersupply.com/d...-voltage-over-current-protection/prod_71.html

 

[GizmoEV]

That looks like a nice one. Remember to use a good volt meter to know what the terminal voltage on the battery is. There will always be some voltage drop over a wire with current flowing through it so the meter on the power supply will read a little higher while charging. As the current drops it will eventually match up.

 

[spdas]

Ok, it is the first time I am charging the TS 400ah and things seem strange to me. The battery started at 3.29v and for 4 hours @20amp the voltage has risen to (at charger 3.57v) and (at battery 3.37) with #8 wire leads. Resting for 10 minutes the battery voltage is 3.35

Question: is there that much capacity between 3.29 and 3.35 that needs 4+ hours at 20amps (80ah)?

I read in other posts people charging to 3.7~3.9v.... seems at my rate I would have to forget about the charger overnite to even get that high. Or where is the "plateau" that will cause very little amperage to ramp up the voltage very fast?

Yes i know 400ah is a LARGE bucket!

thanks Francis

 

[GizmoEV]

Question: is there that much capacity between 3.29 and 3.35 that needs 4+ hours at 20amps (80ah)?

In short, yes! I put 66Ah in a 100Ah cell starting at 3.30V and ending at 3.451V with an ending current of 476mA. These voltages are measured at the cell terminal. Then, I continued charging from 3.451V up to 3.65V and only got 1Ah in with an ending current of 420mA. So, don't assume you are a long way from filling the cell and walk away without a way to turn off the charger when a cell reaches 3.65V or less. I only charge my cells to just under 3.5V because there is so little energy above 3.45V.

HTH,

 

[spdas]

In short, yes! I put 66Ah in a 100Ah cell starting at 3.30V and ending at 3.451V with an ending current of 476mA. These voltages are measured at the cell terminal. Then, I continued charging from 3.451V up to 3.65V and only got 1Ah in with an ending current of 420mA. So, don't assume you are a long way from filling the cell and walk away without a way to turn off the charger when a cell reaches 3.65V or less. I only charge my cells to just under 3.5V because there is so little energy above 3.45V.

HTH,

I am testing another 400ah ts that I previously tested and ran down to 2.6v. It has been on charge @ 20.4Amps for 18 hours.

1: Now the charger is putting out 3.60V and at Battery 3.39v @20.4amps. I don't see any fast voltage escalation yet and keeping a watchful eye as I want to get an idea where the top is, so I can avoid it later.

2: You state your amperage at the end of your charge is about 1/2 amp. ??? My charger is not throttling down yet.
CORRECTION UPDATE: I figured out how to set the voltage limiting amps

I am still a bit befuddled with guys and even you charging 3.451+ (seems like it will take 10 more hours at this rate, so there MUST as you said before a very sharp plateau very soon, that if u do not watch will run away on you.
CORRECTION UPDATE I witnessed the voltage go up quite quickly after 3.5v, even with a 400ah TS and only 20amps, not runaway, but I imagine could be with more current or a 100ah cell.

Francis

 

[GizmoEV]

My Zivan NG1 charging my 200Ah 20 cell pack at ~15A up to about 69V and then starts to ramp back on the current ending at 69.7V 15-20 minutes later with less than 300mA and then the charger shuts off. I have not hooked up a volt meter at the charger output to see how much voltage difference there is in the leads but it really doesn't matter since the voltage difference will diminish as the current does.

These are truly different than any other chemistry battery. Now you are seeing why charging to 3.50vpc is plenty.