More on batteries

I had the same reaction to that video.. it was a folly to begin with. He took one for the team to prove it though I guess.

I've had a similar run with AGMs under bonnet and went back to a cheaper calcium flooded battery for under bonnet about 8 months ago.
Makes you realise how superior AGMs performance is but too expensive to replace every 2 years.

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Well, I warned him but he did not seem to take my advice.
No battery is happy to be located in a hot location. Even flooded lead-acid are happier if not heated.
So, our friend has spat the dummy on the benefits of lithium by being unwilling to allocate a little space in the rear of his vehicle. His choice of course, but in my mind…. pitiful!

Interesting to watch, my DCS extreme has been under the bonnet in the Prado for 4 years and still test as new. Will be intersting to see how long it lasts for. As an aside never got longer than 4 years out of any aux under the bonnet the way I use them so the DCS is doing well.

I'll be watching this thread with interest!

My scenario - LC VDJ200 / twin 130Ah DCS under the bonnet connected in parallel with LVD to ancillary loads / 100Ah VoltX slim in the rear charged via 20A DCDC from the DCS's under the bonnet.

With this system I no longer need to worry about SOC or carry solar panels with me to top up batteries if parked up for a couple of days. Previously I could only get 2ys from either lead acid or AGM's under the bonnet, by this stage capacity was very low & batteries had bulged.

DCS's under the bonnet have now been in service 22mths, 38kkm. Plenty of outback travel in this time, NSW, SA, QLD, Simmo etc.

The DCS App also displays individual cell voltage and to date when charge each cell is within 0.01V of its group, suggesting they are balancing well.

This chemistry degrades quicker at high & low voltages, thus I don't run alternator voltage boost diode with the DCS's as the system has ample capacity without needing to be fully charged, I just place a Victon charger on the DCS's 1 or 2 times a year and take it to full charge to reset the SOC calc. in the BMS.

Whats the simplest way to do a load test?

Regards
Fabio

Smart way of testing

I ran a capacity test on my 100Ah under-bonnet DCS Lithium. It's been under bonnet for over 18 months. At a discharge rate of 5A it took close to 20 hours to extract 97.25Ah. So no sign of any heat-induced loss of capacity. Which is not a surprise, as in my currently model Prado 150, the DCS does not get hot when driving.

I could have extracted bit more, but I opted to stop when the bluetooth switched off at 11.3V . I wasn't intending to go that low, but in light of Leigh's experience I though I may have had a chance to get to 100Ah. However I thought it prudent to stop when the voltage started falling too rapidly. I probably should have stopped a bit sooner.

But wait ... there's more! The SoC reported in the app was nonsense. For each 5Ah extracted, the SoC only declined 1% or 1Ah. This was a consistent discrepancy. So by the end it was just above 80%. Once the bluetooth reappeared when I started to recharge, it had fallen to 0%. Moreover there was implausibly low growth of the SoC as I started to charge - the SoC was climbing much more slowly than the input current suggested that it should. I had this exact same experience when I recently accidentally flattened it. The SoC was very slow to climb, but once it got to around 20% it suddenly jumped to 100%. This suggests a 1:5 ratio between changes in the app and reality. Which makes a mockery of the DCS claim (on their website) that the SoC is highly accurate.

From this I conclude that my recent experience of an accidental flat battery was not due to a heat-induced loss of capacity, because there wasn't any. I now think that the appliances I was using were actually drawing a lot more of the battery's capacity over time than I had led to believe from the displayed SoC, and thus the real SoC was a lot lower than displayed in the app, and eventually fell to too low a level.

As it stands, I'm going to have to install a shunt, as I need an accurate measure of SoC.

First off my battery is older than I thought, it was installed on the 4/12/2019 so is nearly 4 years old.

Battery is a DCS extreme. The battery is located in the right hand battery position under the bonnet and is charged directly off the alternator via a VSR.

Nominal battery capacity is 80Ah, it tested 81Ah when new out of the box and now tests 79Ah with a terminal voltage of 11.5V. So in 4 years it has lost about 2 Ah compared to out of the box but when tested new it was in summer so the temperature would have been warmer a lot warmer.

Car has travelled 37000Kms since then mostly pulling a 1750Kg camper and a good deal of the Kms off road. Battery has mainly been used to supply a 40Ltr waceo used as a freezer, has on a couple of occassions run a drill connected to a 1500W inverter and the battery also powers radio's HF etc and winch though I have only used the winch to pull over a few trees.

Battery is coping with the under bonnet temperatures and has outlasted all other lead acids I have had in that position.

Briste,

I watched a video of the app on the DCS website, it implies it measures Ah in and out even if it only displays it as "SOC". The one in the video seems to track the Ah in and out ok. Are you sure the battery Ah capacity has been correctly entered into the App?

With regards to the original video, I can't see anyware on the DCS website where it indicates capacity loss under bonnet will only be around 1% a year that the presenter quoted. DCS warranty states:

"The battery will be determined to be defective if it fails to deliver less than 70% of it’s rated capacity during the warranty period when installed inside engine bays or engine compartments." Warranty period is 3 years for under bonnet so 10% per year.

They also state in the installation instructions, at least they did in mine not to overtighten the battery hold down clamps. If clamps are tightened to the point where it deforms the case then the warranty will be void. I noticed that one of the battery cases in the video was badly deformed, have no idea why they would have tightened the hold down clamps to that point unless they did fit properly and if that was the case why wouldn't you modify the lamps to suit? I wonder if that was the one that was done to 50% capacity?

From all of the discussions on this “post”, perhaps it should be renamed “Battery Wars” :-)

Macca.

I use a somewhat esoteric but reliable way to determine if my batteries are still providing adequate power after some extensive use.
It goes like this….. 1) Open fridge and remove a beer. 2) open beer and take a good sip. 3) Consider if the beer is cold enough for my desires. 4) If answer is yes then both the fridge and the battery pass judgement. 5) continue to sip remaining beer and marvel at the wonder of the science that can keep it at close to zero degrees Celsius and within my reach. Otherwise known as "All is Good With the World". Ahhhhhhhhhh.

When you are finished with your meticulous scientific battery testing wander over and sample some of my chilled refreshment.