<span class="highlight">Battery</span> update
Submitted: Friday, Nov 24, 2023 at 11:02
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qldcamper
As I have mentioned before I have gone back to a sealed flooded accessory
battery because the AGMs were struggling under bonnet.
For a while now i have been a bit concerned at the rate the voltage dropped off so seeing it was in the 11th month of its 12 month warranty I decided to do a capacity
test.
Using a headlight bulb that drew 4.5 amps I plotted the voltage every hour and was going to run it down to 10.5 volts which is where the
battery companies
test them to.
It was going reasonably dropping pretty
well linear and at 10 hours was at 11.5 volts but at the 11th had dropped below 9.5, so a little under 50ah from a 100 ah
battery.
I spoke with the manager of the company I got the
battery from as I still have my trading account with them and he agreed that was very poor indeed and didnt have a problem replacing it.
I was running short on time when I fitted the new
battery and forgot that my waeco loses its memory when disconnected and turned itself on at a setting of minus 22, I noticed it some 20 hours later and it had reached minus21 so I assume it had been running constantly for that time and the voltage was still 11.5 with the compressor running, not the sort of thing I would recomend doing to a new
battery but at 3.5 amps I thought that was pretty good and confirmed just how sad the first one was.
Reply By: RMD - Friday, Nov 24, 2023 at 15:49
Friday, Nov 24, 2023 at 15:49
QLD
Is your charge amount and voltage as it should be for an AGM, If from alternator it may not be sufficiently high enough to attain proper charge. Does the alternator deliver it's full or near full amp output. With a diode blown in alternator it will be around 1/3 charge flow but will get to near full voltage sort of.
Are your AGM's used under bonnet getting fried with heat, maybe some cooling or insulation may help.
Most people bolt batteries down with clamps and therefore deliver all road shocks and vibes to the
battery in the bay. Using a shock absorbing pad underneath and also under clamping, it might prolong life too. I always use such a pad and the
battery while restrained can always float so to speak.
It might not be the
battery at fault!
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Follow Up By: qldcamper - Friday, Nov 24, 2023 at 16:43
Friday, Nov 24, 2023 at 16:43
Thanks for the
feedback RMD.
I feel that it was the heat that was the culprit as all charging was tailored for AGM.
The flooded
battery that recently failed was set to Redarcs recomended setting for calcium batteries, I don't think vibration played much of a part in its failure as that
battery never saw any corrugations and it was protected from direct heat, but vibration could have played a part in the demise of the two AGMs, but that was the reason I changed to AGM, supposedly more robust.
I think the failed flooded calcium was just a dud from the start as it never held more than 12.7v over night but the replacement holds 13.3v, but it only let me down once in the 11 months but only had light use.
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Follow Up By: Member - Bigfish - Sunday, Nov 26, 2023 at 10:12
Sunday, Nov 26, 2023 at 10:12
The lead acid
battery holding 13.3 is a furphy. It is only a surface charge and will disappear once something is connected to the
battery. Your
battery is fully charged to 100% at 12.7 volts...anything else is , as I said, surface charge and thus irrelevant. Calcium batteries also require a much higher voltage than AGM or lead acid batteries. I believe 14.8 volts is the normal requirement to get 100% state of charge.
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Follow Up By: qldcamper - Sunday, Nov 26, 2023 at 13:15
Sunday, Nov 26, 2023 at 13:15
Thanks big fish, but you seem to have missed the point of the post.
It was meant to demonstrate how a basically faulty
battery can still perform
well enough to appear to be serviceable.
It was not intended to argue the physics of batteries with people that have little more knowlege about batteries than what they have read on the internet forums mostly written by people with about the same experience as themselves.
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Follow Up By: Batt's - Sunday, Nov 26, 2023 at 22:57
Sunday, Nov 26, 2023 at 22:57
I wouldn't say the calcium
battery holding more than 12.7v is a furphy.
Mine held a very similar amount of volts according to the voltmeter as my agm batteries did this was for over 5yrs till it died. It was a Supercharge Allrounder that was used for the starter
battery and also ran a Waeco CDF11 console fridge which was used quite a lot and the voltage was usually any where from 12.7v to 12.9v the next morning after running the fridge from memory around 2 or 3 deg. I had a 110amp fixed solar panel feeding it when parked in the sun. Before I fitted the solar panel the
battery volts sat around 12.7 then around 13.0v to 13.1v which it would hold overnight when the fridge was off. I've talked to people about it before on here and as a
test I have even turned the headlights on for a bit to drain this surface voltage when the sun went down and still had the previous voltage mentioned in the following morning. While some people have their doubts I know I was able to run my fridge for longer.
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