thanx🤝 your explanation was very helpful especially in understanding why the 14.4v and 13.8v actually mean on those batteries for charging and how to determine the charging current  👍 super helpful

Excellent video, thanks.

Excellent. Thanks

your recommended voltage is wrong and the charger cant tell the type of battery. However for recovering dead batteries, you want a higher charge voltage. You start with a high voltage, as high as the PSU allows, then once it starts taking it current you change the max voltage to slightly higher than normal.


the recommended voltages are as follows:
wet: 14.7V
gel: 14.4V (some gel battery manufacturers that make the ones you used for this video print a spec on the side, the initial max charge current, and the charge voltage.).
AGM: 15.2V

i add a tiny bit more volts. like 0.1V for recovering dead batteries. If the environment is hot, reduce the voltage a little bit during normal charging.

You also want to keep the battery in charge voltage longer if you are recovering it. During recovery it takes very long to charge, takes a lot of energy and releases heat in desulphating some hard lead sulphate. The float voltage differs between battery types too.

You can add battery water to a gel battery, it comes sealed but it has a place to unseal, just lift the cap. So you can turn a gel battery into a wet battery but its too easy to overfill.

I have the same little charger. If yours is exactly the same, Under the sticker  there should be a potentiometer you can adjust to change the cut off voltage, the voltage where it goes into maintenance mode.

👍

Cool man

Excellent. I usually charge lead-acid batteries with a constant current/voltage source. In the first stage, I charge at the recommended voltage of 14.4V to 14.8V, depending on what the manufacturer recommends, but I usually leave it at a maximum of 10% of the nominal current, or even less, for large-capacity batteries. Then, when I notice a low current consumption, I move on to the float stage, which varies between 13.4 to 13.7V, depending on the manufacturer. I always choose a slow charge in order to maintain the maximum battery life. In situations where I have not used the batteries for some time, every three months, I try to maintain the float charge for a maximum of 0.1C, 12 hours or more, the time that I notice a low current consumption, of 100mA or 50mA, depending on the battery capacity. And this charger does most likely te same, but with more current, to 1.5A limit.

I believe your tiny charger is charging with amperage limitations, so it's just doing the best it can and appropriate for small capacity 12V PB batteries only.

Victron have a default setting of 4% of the AH for lead acid, they call it tail current. So, 0.28A would be about right for 7AH. Nice Tutorial.

Car batery manufacturers such as Baner, Exide, Yuasa, Varta, recomends no more than 0,1C charging current. For example 75Ah battery can be charged with 7.5A current max. 12-15 h is normal charging time.

I have a car battery smart charger 1.5 amp, when my car battery 65AH 600CCA fully charged the float mode activated and the reading is 0.536 Amp current and 13.53 dc volts reading, now my question is does the battery degrade (hurt) because of the 0.536 Amp current??? 0.536 amp current is not changing after 8 hours of float mode, then i unplug the battery charger.

I don't think car altnators have a current limit.  So if you sit listening to some music, and knock some charge off of the battery, and start your car, it's gonna dump a lot of amps into the battery, right?  So that 0.3C factor would be out the window.  And that happens ALOT.  SO what gies?  Also, I recall a lm317 data sheet showing a lead acid charge circuit with two lm317s.  One set up as a voltage reg at 13.8 volts - set up to feed into a second one set up as a current limit.

would be really interesting to see how those MOTOPOWER chargers on amazon compare to the one in this video.

Two questions please:

1) At the start of the video, the charger is plugged in and in default mode - if the two leads touched together what would happen?

2) You say the battery can stay charging in Float mode indefinitely - will any degradation occur long term over months or years? Or is this healthy for the battery?

thank you

I don’t see a video on your site for using Lithium Chargers for LiFePO4 type of battery and I would like your input. Different chemistry of Lead Acid and Lithium to take into account when charging.

The SLA charging video’s were excellent especially since you were using ‘Smaller’ size batteries and not the big automotive style. You also were explaining the science of charging Lead Acid style batteries.

The Powertank device for powering a telescope which I mentioned in a previous posting to you, is currently a SLA 12v 7AH sizes. It appears there are LiFePO4 options in both 12v-7AH and 10AH battery sizes that should fit in the battery compartment and provide much better run time performance if converted. The Powertank you have to disassemble it to remove the old battery and is quite a process. Other’s have mentioned on conversion a different charger would be needed due to the monitor circuitry inside the Powertank is for SLA and will not give proper charge or discharge information on the series of indicator lights. I suppose the power curve difference of Lithium and Lead acid. The Powertank has outside post’s that could be used to attach an external charger.

The chemistry for LiFePO4 is totally different from SLA and charging would be different as well.

What amperage of charger for this ‘smaller’ type of LiFePO4 should I be looking at purchasing?

Would be a great additional video should you decide it is worth your time in producing

Thank you for your time and expertise!

How have you got this rig connected? It's not clear to me.

Thanks for this excellent video. Are you at liberty to share the make and model of the 12v charger you demonstrated?

I will pose this issue to get your take.
I found out the SLA battery has F1 connector wires inside my Celestron Power Tank and I believe I would like to go LiFePO4 battery which has F2 connectors.
Will it be ‘Safe’ to use a F2 to F1 Adapter for this Lithium type of battery?
I have found SLA battery’s doing such but Nothing on Lithium.
Thank You!

Hi, just watched your vid and very interesting it was. Thank you. A question though if I may. I'm looking for a 12v dc supply for a 'Chinese' diesel heater for my workshop. The heater requires a 'cooling-down' period that makes use of its own internal fan but if there's a power cut (ie the fan is stopped) there is a likelihood that the heater's motherboard will be overheated and fail.

To counter this it seems that many have fitted a 12v battery which would not only provide the main working power but also backup power in a situation where a mains failure occurs. I thought I'd read that they had also fitted a permanent charger (as in your vid) BUT surely this would cause an issue when mains power exists as (as shown in your vid) even if the battery was fully charged the charger would still be providing some 13+ volts into the heater......or have I misconstrued something? Would the 12v heater be able to sustain 13+ volts do you think? Any info would be appreciated.