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rgleason · 17-12-2018, 20:51

Quote:

Originally Posted by john61ct

Each cell needs to be load tested separately, you don't do a whole bank at once.

And no need to use the 20-hour rate with LFP, Peukert is not significant, .3C even .5C rate should be fine with robust wiring.

Believe I already suggested you look at the iCharger 4010-Duo, apparently controls discharging up to 200W or 70A, but has a steep learning curve, just now working my way through the main support thread. . .

But adjusting the load manually should be do-able, just tedious sitting there watching the ammeter, maybe checking every 20min or so accurate enough for our purposes?

A DIY project with Arduino or rPi might be fun. . .

Thanks John. "...load test each cell separately" You must mean each battery.

I have the SG200 connected to two T105 in series 12vdc, and was seeing how that worked too.

I suppose the SG200 could be connected to a single 5vdc T105 which would mean I could use my little 15a inverter without having to stop, but I really should find a better way.

icharger is good but too much $. Checking is too tedious and error prone.

I need to follow up with some of the circuit projects.

john61ct · 18-12-2018, 04:35

I doubt that there are automated dischargers of sufficient capacity for less.

Yes manual load testing is tedious, that's why people usually pay others or just don't bother.

Yes I meant breaking banks to test the lowest, denominator component batteries. On my LFP those are 3.2V cells, with lead can be 2-, 3-, 4-, 6- or even 12-volt batteries.

I don't know the relevance of the SoC meter here, unless your load testing is to verify the accuracy of its SoH reading across the bank as a whole?

Doesn't work at lower voltages right?

It needs a stable learning period right?

Note I came across references to "standard light bulb racks" to use as resistance dumps with variable loads in the RC battery and endless sphere forums. Discharge testing seems pretty routine over there, just realize LFP is rare compared to other different voltage lithiums.

Seems many hobbyists once they have a DIY design that works, publish the schematic or even make the devices for others for not too much.

john61ct · 18-12-2018, 18:48

Here's a discharger lots of positive reviews from the electrickery geeks

https://www.amazon.com/Battery-Capac.../dp/B078W3Q27C

cheaper via alibaba of course

john61ct · 20-12-2018, 10:24

vdo I came across

https://youtu.be/hkoPMT67s0U

rgleason · 20-12-2018, 18:28

Quote:

Originally Posted by john61ct

Here's a discharger lots of positive reviews from the electrickery geeks

https://www.amazon.com/Battery-Capac.../dp/B078W3Q27C

cheaper via alibaba of course

Looks pretty good. $119.00

Capacity test: 10Ah, the resolution of 0.001Ah; 10Ah-100Ah, the resolution of 0.01Ah; above 100Ah, the resolution of 0.1Ah
Dischage power: max 200W, it should be controlled within 90% for a long time working
Connection: four-wire detection, voltage and current channel separate wiring, to ensure measurement accuracy

Thanks.

rgleason · 20-12-2018, 19:04

Thanks John,

$13, wish it could be used for FLA, AGM etc.

150w/12.8 = 11.718 amps ...which is pretty close to the 11.25 that I need and IMO it is better to be oversized by 25% for various reasons, heat, being to close to the max values, etc.

Couldn't two of these be used together, each set at 5.63 amps, if only they would work with FLA.

Why wouldn't they work?

Quote:

Originally Posted by john61ct

vdo I came across

https://youtu.be/hkoPMT67s0U

Cellmeter 8 Review and Walkthrough

**newhaul** · 20-12-2018, 19:46

Unless you are doing the ah testing for hire who actually needs that .01ah capacity
For personal testing and setting of onboard meters testing to nearest ah would be more than plenty.