PR Battery Pack Maintenance

[mikeh99]

I have found my PR battery pack does not maintain it's charge very long. Does anyone know how to overcome this. Except for the occasional camping trip it is only used during power outages. I'm afraid if I leave it plugged in it will kill the battery like in a laptop.

[PaulaO2]

Does it have a built in "trickle" charger? If so, then it should be fine.

If not, or if you don't know, then just get in the habit of plugging it in for a day each month.

[archangle]

Is it a lead acid/Gel cell/AGM type battery? Have you got a model name or link. The one I'm familiar with is.

Even "trickle" chargers may eat a battery over a period of months of constant charge.

What you need is a charger specifically designed for 24/7 connection to the battery. These are often called "float" chargers.

What does Respironics say in terms of using the charger that came with the battery?

Unfortunately, there's a lot of bad information or missing information in the battery and battery charger world. Some chargers that aren't true "float" chargers are marketed as if they are. Some chargers that are designed to be float chargers may not reliably go into float mode and may eat your battery.

One thing you can do is buy a weekly electrical timer. I bought one made by Woods at Walmart. You plug it into an outlet and set some little tabs on it. The dial goes around once per week and will come on for the time period you set the tabs to. You can set it to come on, for instance, 12 hours one day a week. This way, your charger has less time to slowly eat away your battery.

You also need to realize that rechargeable batteries do die over time no matter what you do.

There are some tricks and special chargers that will "revive" batteries if certain problems occur, but they're very iffy. Also, the battery may go bad again pretty quickly even if "revived."

How old is your battery? How has it been maintained? Have you run it down many times? Has it ever sat a long time without charging? Has it ever sat for a long time while discharged?

[mikeh99]

I actually tried the one month routine but it seems to discharge in that time. PR documentation is almost nonexistent so I'm not sure what kind of charger it comes with. It does have an LED: amber for low, green for charged. Last time I needed it I only got maybe 20 minutes.

[PaulaO2]

Float! That's the word I was looking for. Brains would be a wonderful thing if I ever used it.

The wall timer sounds like a good idea.

[archangle]

I actually tried the one month routine but it seems to discharge in that time. PR documentation is almost nonexistent so I'm not sure what kind of charger it comes with. It does have an LED: amber for low, green for charged. Last time I needed it I only got maybe 20 minutes.

Was it fully charged just before you used it and got 20 minutes?

I was suggesting weekly, but if it's discharging significantly during a month, that probably means it's dying on you.

If it's the black bag thing I'm thinking of, open it up and look at the battery inside. Post a picture of the labeling on the battery if possible. You can probably find a replacement battery for a lot less than a new battery pack.

Be careful in case there's some sort of leakage and/or corrosion on the battery.

Or for that matter, you can probably just buy a car jumper battery pack for a lot less money that will work just as well as the Respironics battery pack.

One thing you might try if it you can figure out how to do it. Try hooking it up to a standard car battery charger, but put the charger on its lowest current level like 2 Amps. Get it fully charged that way, and try again. Sometimes those slow chargers will sort of get into a "confused" mode and not fully charge the battery.

[SuperSleeper]

For charging of 12 volt batteries using grid power, I use a BatteryMINDer Charger/Maintainer/Desulfater. Google it or you can get them on Amazon. Mine works flawlessly and it desulfates my lead-acid deep cycles also. Trickle charges up to where it's supposed to be, then desulfates also after that.

I paid about $35 for mine on Amazon a couple years ago, they appear to sell now for around $37 or so.

On 2 of my very old (6 years at least) 12-volt marine deep cycle batteries, standard trickle and auto chargers couldn't bring them back, but this desulfator actually brought them back to life after sitting on this charger constantly for 2 weeks.

[archangle]

For charging of 12 volt batteries using grid power, I use a BatteryMINDer Charger/Maintainer/Desulfater. Google it or you can get them on Amazon.

I would be very careful to NOT hook this charger to a battery that is connected to a CPAP machine. Disconnect the BatteryMINDer from the battery before connecting the CPAP to the battery. (Disconnect, not just unplug from the wall.)

The BatteryMINDer sends high frequency pulses to the battery to try to break down sulfate crystals on the plate. I can't find the specs right now, but I think the pulses were around 1.4 MHz at about 1 amp. I would be concerned about what these pulses might do to electronic devices connected to the battery. I'll have to see if I can find the manual that came with mine, but I think it listed the frequency involved.

The BatteryMINDer may put these pulses out even when the charger is unplugged. The desulfation circuit runs off the battery if necessary.

It's a good idea to disconnect the charger from the battery before connecting to the CPAP with any charger, but the BatteryMINDer is especially important to do this with.

Once the BatteryMINDer is disconnected from the battery, the battery will be fine to connect to the CPAP machine.

[archangle]

I found the quote.

"VDC Electronics, Inc. has created a simple method of generating the required resonant frequency (3.26 megahertz pulse) to breakdown the lead sulphate crystals, allowing the molecules to return to the battery’s electrolyte. By creating a waveform with required 3.26 MHz frequency, coupled with a very fast rise time and a high amplitude pulse, more energy is developed to breakdown sulphation than by any other method believed to exist. On February 6, 2001 this unique approach was granted a US Patent."

3.26 MHz and "high amplitude pulse" don't sound like something I want going into my CPAP power supply.

[SuperSleeper]

Yep, right Arch... forgot to mention that.

I NEVER attach any grid-attached battery charger to a battery that is also attached physically to my CPAP machine at the same time.

For that matter, as far as grid-connected AC to DC chargers, I don't charge any of my deep cycles while they're also attached to any electrical appliance, not just CPAP. My DC only solar power charge controller is the only exception to that rule, but mostly because it's designed for use while also receiving the (relatively small) charge coming off the panels during the day, so the risk is mitigated somewhat, and the risk of voltage spikes and surges on an off-grid solar panel system is quite small.

My solar charge controller also also has a desulfation mode, but it has circuitry that can sense when there's any load on the batteries-- and it will not go into desulfation mode during that time.