Infinitum Desulfator Review
There are countless desulfator schematics on the internet and I had built two before with no success in their claims. The circuits are the typical 555 oscillator and mosfet-inductor-capacitor boost circuitry that produces high current, high voltage, short duration spikes. It does what the circuitry is designed to do (produces spikes) but it never did what was intented to do (restore batteries).
There are lots of online ads in sites and social media about commercial desulfators and lots of positive reviews but mostly posted on their pages. But I have not seen a direct comparison or even measurements with readings taken on a battery analyzer (internal resistance and CCA).
My old C&D Tech DCS batteries used for my solar setup are approaching 3 years and their age is showing so I thought, let's try it here. So, I decided to bite the bullet and see for myself. I bought one for about US$52. When I received it, it feels solid and heavy. It appears to be potted, so no teardown pics without destroying it.
Local seller says 1 week of desulfating and we should see positive results! I received my unit around 10 Sept 2016 and attached it to the batteries and the measurements were taken right before attaching it and a while ago after taking the "after" readings (23 Sep 2016, a little under 2 weeks).
Here it is attached.
The readings are written with a sharpie on the batteries.
First, Internal resistance.
The start reading is 5.11mOhm. After is 5.88mOhm. Lower is better.
Wait, what? It increased?
Now, for the CCA rating.
The start reading is 518CCA. After is 450CCA. Higher is better.
Aaaand, it decreased.
So, this battery got worse.
For curiosity's sake, last year's reading was 808CCA.
Now, the weaker battery's internal resistance.
The start reading is 33.88mOhm. After is 58.45mOhm.
Now, for the CCA rating.
The start reading is 78.2CCA. After is 45.33CCA.
Yup, there is a trend here. This battery also got worse.
Last year's reading was 798CCA.
It may be the batteries are nearing end of life since one of them has started to buldge so I stopped the test for now.
So, what does it really do, electrically? I decided to take measurements to find out.
Here is the test setup. A big capacitor is used in place of a battery. In the negative line, a 200A 75mV shunt is placed in series so we can measure the pulse current. Power is supplied via a bench supply to the capacitor terminals.
For the test, I chose 12.5V as the testing voltage.
Below 11.5V, red LED is on and the circuit is doing nothing, consuming 14mA.
Between 11.5V and 12.3V, no LEDs are on and it consumes 15mA still doing nothing.
Above 12.3V, the green LED turns on and the circuit starts pulsing, consuming 21mA.
The blue trace is the voltage across the shunt. At 200A it would produce 75mV so it would mean that at 114mV peak it is producing 304amps peak!!! That is pretty huge with only a 12.5V and consuming only 21mA. Changing the supply voltage does not seem to change the current much.
The pulses are also occurring at a rate of 1.1kHz which is similar to the 555 circuits on the internet but the ones I have built in the past did not produce this much current, maybe about 100A tops.
The 304A peak spikes are measured at 52ns wide. Very short but very high peak current.
With the 15,000uF capacitor, I was measuring a delta V of about 11.2V so that means it has a resistance (ESR plus short 12ga interconnects and maybe some inductance) of about 37mOhm.
It does what other desulfators do but better, such that it consumes so little current but produces a very high peak current so it seems to have good efficiency and has that going for it. It does not seem to have helped my batteries. Maybe there are other factors that could affect the results, if the batts are salvageable (mine could have been beyond saving so, who knows). Conclusion will be open for now until I try it on other types of batteries and see if it would have an effect. I will update this page when I have new results.
22 Oct 2016:
Here is a C&D Tech Hi Rate Max UPS AGM battery that has become weak.
Test started at 9/23 with ESR readings of 9.01mOhm, at 10/01, it was 8.58mOhm. At 10/22 it was 9.09mOhm.
Now for the CCA readings.
Test started at 9/23 with 293CCA, at 10/01, it was 308CCA. At 10/22 it was 291CCA.
Still no bueno.
All this time, there is a charger connected to it 24/7 set to 13.8V and the battery was consuming about 130mA (including the desulfator connected)
I had been contacted by Infinitum several times as I seem to not have much luck while there are lots of reviews posted by them that are positive.
There are, however, in some forum I saw that also had the same luck as me.
Third time's the charm? Let's try it in my car which has the same AGM battery installed March 2015 but still running OK-ish.
Test started at 10/22 with ESR of 3.41mOhm.
When I bought the battery as used, it read 1100+CCA. Now, it is down to 775CCA.
Let's see how this one fares with the desulfator in place.
Stuck on the side and leave this running for a few weeks.
17 Apr 2017:
Almost 6 months later, and the car is used several times a week.
Still no help. CCA reading still dropped. from first install of about 800CCA, it is now at 584CCA. Internal resistance also increased from initial reading of 3.41mOhm and went up to 4.5mOhm (not shown).
So I guess I can probably say this does not have an (or have little) effect on AGM batteries. I will still test it on flooded lead acid when I get the chance and maybe it would be more effective on those.
30 May 2017:
I had the desulfator connected to the AGM battery for 8 months and now it failed. It could barely start the car and the voltage is always low, charging it does not help as it just gets really hot.
CCA dropped from 1100 when I first installed it in the car, 800 when I installed the desulfator and now it is just a little over 200.
Internal resistance is also really high. The sides of the battery has also bulged a bit so that is the end of it.
Since the AGM battery already failed, I went back to the flooded lead acid type. This is the same type that I previously used and it lasted about 2 years without a desulfator.
I still have the Infinitum connected so we shall see if this will have an effect on extending the battery useable lifetime.
It is still pretty low as the battery has just been freshly installed and it is a dry-charged battery. It will need a few charge/discharge cycles to "break in" and hopefully improve.
Internal resistance is 8.8mOhm.
After charging overnight, CCA increased to 446.
And internal resistance dropped to 5.93mOhm
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