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Another dead battery. What's the favorite charger/maintainer of the board?


opticsguy

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However, unless I had a charging station which monitors each battery, I still would not put a single charger on multiple batteries unless I was there to monitor them, whether parallel or series.

If you are using a constant voltage charging method, then physics laws themselves act as a limit, so you don't need anything more than a fused circuit.

 

Anyways, anyone remember those old chargers on NiCad batteries that said it took a whole whopping 8-10 hours to charge? Then remember those new chargers that came out that promised 1-2 hours of charging? The old chargers used constant voltage, and it took a long time for the end of cycle to charge. The new chargers used automatic circuitry to monitor the charging process, so therefore they could use higher voltages than normal towards the end of the charge cycle, so they could keep pushing more amps.

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Here are the main things to remember about Life batteries.  They are happy when charged to at least 13.8V and are at risk of damage above 15.2V so almost any Pb charge terminate voltage is fine.  They are fully depleted, however, below 12.7V  and if you let them dwell below that low voltage state, they can quickly de-plate and be damaged.   Since some 'smart' charger for Pb let the voltage droop as low as 12V before restarting a charge cycle, you want to be very careful about which external charger you use.  Also, if you have an anemic Reg/Rect like mine was, then can end up with a never-really-charged battery which means almost no time if the coils or RR drops out and problems starting if the plane has sat for any length of time.  But they won't catch fire under virtually any circumstance. 

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Here are the main things to remember about Life batteries.  They are happy when charged to at least 13.8V and are at risk of damage above 15.2V so almost any Pb charge terminate voltage is fine.  They are fully depleted, however, below 12.7V  and if you let them dwell below that low voltage state, they can quickly de-plate and be damaged.   Since some 'smart' charger for Pb let the voltage droop as low as 12V before restarting a charge cycle, you want to be very careful about which external charger you use.  Also, if you have an anemic Reg/Rect like mine was, then can end up with a never-really-charged battery which means almost no time if the coils or RR drops out and problems starting if the plane has sat for any length of time.  But they won't catch fire under virtually any circumstance. 

 

As I understand, you can "shock" batteries back to life with a voltage double that of rated when done for a short time (a few minutes), but eventually the plate damage will outweigh the benefit.

 

Here's a neat little thing: http://batteryminders.com/prints/aviation/aircraft-battery-trials-concorde-sealed-wins.pdf

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That would indeed be a shock, but batteries are almost constant voltage so trying to double voltage would need something like thousands of Amps for typical Pb or Life battery and would be fatal, probably for the person trying to charge the thing as well.  There is much talk about using pulsed high current to effect desulphation of Pb batteries but look close and you will see that most battery manufacturers do not recommend the treatment.  Mostly that's because there are lots of reasons a battery can die, slow sulphation is only one and trying to pulse charge/ desulphate can cause leaking and outgassing if that was not the root problem.

 

In any case, there is no such failure mode to LiFe batteries.  If they are dead, then you would want to trickle charge them to try to bring them back, preferably with a balancing charger.  High currents are the worst thing you can do to a deeply depleted LiFe battery

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Oh hey. I just realized "LiFe" is the chemical composition. I was confused, wondering what a "life" battery is, then you wrote "LiFe" and I realized you meant Lithium Iron Phosphate.

 

Also, why would you need thousands of amps? Just put a 24v charger for a minute so when it's discharged. As long as you don't have some crazy charger that CAN push thousands of amps, it should help break up the sulfidation enough to use a normal deep cycling charger. I've brought back batteries that smart chargers were refusing to charge this way, and then did a couple deep cycles. It doesn't bring it back to 100%, but it's gotten extra life out of the batteries for me.

 

Finally, I was only referring to lead acid batteries. I don't know enough about LiFe batteries, I wouldn't use this method on anything except a lead-acid battery.

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What happens when you put the 24V charger on it is that the thing will current limit as its voltage collapses down to the 12V battery level.  And yes, that will desulphate a Pb battery although pulses (followed by high discharge pulses) are supposed to work better.

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What happens when you put the 24V charger on it is that the thing will current limit as its voltage collapses down to the 12V battery level.  And yes, that will desulphate a Pb battery although pulses (followed by high discharge pulses) are supposed to work better.

 

Negative, I didn't use a smart charger for the short burst, it's an old constant voltage charger (REALLY hard to come by nowadays). It doesn't have the ability to push a load of amps, so I wasn't worried about overloading the battery.

 

Note, this isn't an aviation battery that I am talking about, by the way.

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It's amazing how fast the 912 will crank with a charged battery.

 

I took the old battery home (11.8V) and did a regenerate charge with my CTEK 7002.  That charger follows Odyssey's recovery charge method.  I'll be darned if it isn't showing 12.9V after being off the charger for a day.  It may be better then the "new" battery I got from Amazon which had a "March 2013" build date and only had 12.5V out of the box (I charged it before switching batteries).

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That cannot be answered without knowing the temperature. Battery voltage is directly related.

 

In general, at around 68 degrees Fahrenheit, If the charge is below 11.7, it must be charged immediately, this is when sulfidation begins in lead acid batteries.

 

The following reference says 2.29 volts per cell is the recommended charge float voltage at 68 degrees, and I will assume there are 6 cells. Chanik on this forum said these batteries like to hold a voltage around 13.2 volts, which is right in range with what I know about lead acid batteries (12.8 to 14 volts is typical).

 

http://www.jantechups.com/userfiles/files/Battery/Enersys/VRLA/PowerSafe%20SBS/USSBSIS0060208PowerSafeSBSInstructionSheet.pdf

 

I just got the NOCO Genius 1100 battery charger from NC Bill here on this forum, and I am very impressed. It had an AGM mode (sbs 8 batteries are absorbed glass mat batteries, so they have a little different charge characteristics). It quickly identified my old battery as shot (we knew this), and the new one that just arrived in the mail is good.

 

 

Here's a good refresher on lead acid batteries: http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

 

And here is AGM batteries (like the SBS 8): http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

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