Backup power on power recliner

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Re: Backup power on power recliner

Postby flagman1776 » 27 Sep 2017, 16:25

The transformer is indeed very heavy like a lead brick. There's a small door to the (2) 9v "backup batteries" in the bottom of the transformer case. I opened the case proper once and I was surprised, it is indeed full.
The power out to the chair is a very small 2 pin plug on one end... it's deceptive... I didn't even realize it was a plug. The wiring is hidden under the chair...
The 110vAC power in is a common US 3 pin cord from the opposite end.
I left the backup battery access door off to connect my present multi-AA backups to that wiring... I have them stashed under the transformer now.
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Re: Backup power on power recliner

Postby flagman1776 » 08 Oct 2017, 19:32

Now that I have resolved the issue with the defective cell holder... discussed separately here: viewtopic.php?f=2&t=7334

I have installed the (2) "12v DC" back up packs. I realize they are only feeding into the transformer's backup feed through tiny wires... acceptable for short emergency use. But it does work & more reasonable speed... if you need to get up, you need to get up. Typically a bathroom trip at 3AM.
Better batteries would be nice & I'll monitor the lifespan of the disposeable ones.
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Re: Backup power on power recliner

Postby Burgerman » 08 Oct 2017, 19:41

The real problem is that if you pull half an amp from those dry batteries the voltage falls from 1.55 to about .7 of a volt. They have a high resistance. They are hopeless at higher amps.

If you were to substitute those for a set of eneloops, which have much lower resistance, your voltage will not collapse, the chair will work more reliably and faster, and some are good in standby for many years. So recharge every 6 months.
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Re: Backup power on power recliner

Postby flagman1776 » 31 Oct 2017, 18:59

the power is out. my AA cell backup in not working. So I can't recline to sleep. *&^%$#!
I'm at McDonald's on a ratty old laptop... I power sag? never has decent power. I think I need a ups. I suspect the way the 2 oem 9v transistor batteries is, is just a piece of crap.
I tried the cheap way & it's just not what I need.
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Re: Backup power on power recliner

Postby Burgerman » 31 Oct 2017, 20:13

Yep...
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Re: Backup power on power recliner

Postby Burgerman » 31 Oct 2017, 20:15

The real problem is that if you pull half an amp from those dry batteries the voltage falls from 1.55 to about .7 of a volt. They have a high resistance. They are hopeless at higher amps.

If you were to substitute those for a set of eneloops, which have much lower resistance, your voltage will not collapse, the chair will work more reliably and faster, and some are good in standby for many years. So recharge every 6 months.


:argument banghead banghead banghead hanged
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Re: Backup power on power recliner

Postby flagman1776 » 02 Nov 2017, 18:43

I really suspect the tiny wires used for the OEM 9V transistor batteries are throttling any power I apply. Yes, AA cells are limited but they must have many times the power of the OEM batteries.
If the power fails during the night... how much draw is there while the controls are powered up but no motor draw? I didn't act on it but a possible solution was suggested, to switch off the back up power when not needed for hours at a time. The first use was slow but adequate. After that not.

There are AC > DC > AC > DC ineffiencies in a UPS but... when I'm on generator, it can recharge for another night of use...
I'd like to know if others who posted UP SIZED their UPC... & how much... which are really intended just to protect a light load like a computer for a short period.
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Re: Backup power on power recliner

Postby Burgerman » 02 Nov 2017, 19:00

I really suspect the tiny wires used for the OEM 9V transistor batteries are throttling any power I apply.


If they throttle it by 2 percent then they will smoke. And by 5% they will melt. That 9v battery is designed only to lower things. Not raise them. My bed has one down, but not up!

Yes, AA cells are limited but they must have many times the power of the OEM batteries.

Define "power"?
If the power fails during the night... how much draw is there while the controls are powered up but no motor draw? I didn't act on it but a possible solution was suggested, to switch off the back up power when not needed for hours at a time. The first use was slow but adequate. After that not.


Non if its just switches. A low level if its got electronics/leds etc. Or a screen.

There are AC > DC > AC > DC ineffiencies in a UPS but... when I'm on generator, it can recharge for another night of use...
I'd like to know if others who posted UP SIZED their UPC... & how much... which are really intended just to protect a light load like a computer for a short period.


Many computers have a 350 to 1200 watt power supply. And take many times as much power as your chair. They have 20, 30, or 40A available on the 12V rail, and more on the 5V rails. You will be drawing a few amps, only for a short time. But you need a battery that is low enough impedance to do this! AA cells will not do it. Enerloop are 3 times better than mose cheap rechargable AAs, and massively better than non rechargable alkalines etc.
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Re: Backup power on power recliner

Postby flagman1776 » 02 Nov 2017, 20:49

Interesting points.
The wires didn't melt. Each pack started at 12+ volts & is now at 11.5v. The cells I used are Rayovac Alk.
What's up, what's down? The chair back reclines and leg support lifts.
At rest the seat has a pronounced back tilt (not to mention I have a 1" shim under the front for more leg lift I need to counter leg swelling (and additional foam cushion added to the leg area).
So to get out of it, I need ro "raise" the seat at least until it's level or preferably a bit of lift.
There's only dumb switches. No lights, no screens.

It does have the brick heavy power supply described by another previously.

I'm reluctant to buy the enerloop... install them in the cheap holders... risk them being inadequate too.
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Re: Backup power on power recliner

Postby flagman1776 » 05 Nov 2017, 15:36

I have been trying to research backup power for medical devises... that approach is "just make it bigger". Really doesn't seem sensible for my application.

The enlarged power packs I assembled worked, initially. What I didn't do, was install a cut off switch... so the drain eventually ran the batteries down. Heck, it wouldn't need to be powered up, except in an outage!
I HAD moved the transformer to the shelf, though it's on my weak side. Can I reach it? I'll see. Maybe more work needs to be done to the access point. If I install a DPST switch, the batteries should be good when I need them. In that case, a KISS backup system looks better & better. In that case I'd be inclined to upgrade the cells.
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Re: Backup power on power recliner

Postby flagman1776 » 06 Nov 2017, 03:17

In the fully reclined position, I can't reach the transformer on the shelf "beside me". As the chair reclines, it moves back. It looks like it will interfere with other furnature if moved forward though I'll need to verify it. There is already a makeshift extension of he shelf... Some moving of the chair, improving of the shelf extension... My thought is to attach a switch to the transformer & the batteries under it.
Progress but baby steps.
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Re: Backup power on power recliner

Postby ex-Gooserider » 07 Nov 2017, 01:10

The problem that happens with many UPS's (not all) is that they will run a load until their battery dies, but will NOT start a load if they weren't on when the power failed, or if the load got plugged in after the power failed... So it doesn't work to have one sitting on the shelf charged but not plugged in until the power fails...

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Re: Backup power on power recliner

Postby flagman1776 » 17 Nov 2017, 21:19

I thought the 16 Alkaline cells were still in good shape... and 14 of 16 were when I tested again. 2 were very weak & were disposed of while I use the rest up in general use.
I have bought a set of the Evolope cells but I'm convinced that there needs to be an on/off switch on the back up packs. It's easy enough to interupt the wires with a toggle switch. Positioning so I can reach it when reclined is more complicated.
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Re: Backup power on power recliner

Postby Burgerman » 17 Nov 2017, 22:39

I'm convinced that there needs to be an on/off switch on the back up packs.


Why dont you measure it?
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Re: Backup power on power recliner

Postby flagman1776 » 18 Nov 2017, 04:05

Measure what? The draw when the line is off? I wonder if it's different when the line is switched off VS when the line has no output but it stiill connected. Might the transformer be backfeeding the house? Shouldn't be but with these low budget transformers... I just don't trust them. For a $2 switch...
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Re: Backup power on power recliner

Postby Burgerman » 18 Nov 2017, 11:59

Measure the draw when idle. Measure it when idle and the wall power is gone too. If its super low or non existent then thats not the problem. No info? Thats called guessing. It doesent help.
Might the transformer be backfeeding the house?

no...
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Re: Backup power on power recliner

Postby ex-Gooserider » 21 Nov 2017, 03:39

A transformer can't make AC out of DC, so it can't be backfeeding the house. But you may have a leaky cap or other resistance in the circuit that will act as a drain on the battery pack...

What you have is a transformer that turns the 110VAC current coming out of the wall to some lower but still AC voltage. That lower voltage gets passed through a diode or possibly a rectifier bridge (just multiple diodes) which gives you very 'noisy' DC. Typically this then goes through some circuitry that filters out the noise and then sends the DC on to the rest of the chair.

To see what is going on, get an AMP meter (ammeter) or a meter with an amps scale, and wire it in SERIES with the battery pack. If using a meter with several scales, start on the 10A scale, and switch to lower scales as long as you don't get a reading.... DO NOT try operating the chair when on the battery pack with the meter set to a low scale!

You should see ZERO amps flowing with the AC power ON, either when just sitting or when operating the chair.

When the AC power is OFF, you should ideally see zero when the chair is just sitting. More than one or two milliAmps is a possible problem. You will see power draw when cycling the chair (If you don't, there is a problem with your wiring....)

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Re: Backup power on power recliner

Postby flagman1776 » 22 Nov 2017, 20:12

Thanks. Yes, I'll dig out my clip leads & test. I am running the new cells through the charger, just to be sure. I found that not only had 2 new alk cells failed prematurely... I found evidence of leagage where I had the removed cells sitting on my desk... and when I turned a cell holders over, one space had evidence of leakage! Modern cells have become so good... this was really unexpected.
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Re: Backup power on power recliner

Postby flagman1776 » 27 Sep 2018, 22:19

We had a line of intense thunderstorms last night as we were getting ready for bed. They were loud & close. They seemed to be gone & I settled in to watch TV until I fell asleep in my power lift chair.
I woke up suddenly, about 12:30AM... to a dark house. The power was out. It wasn't an emergency... yet... but next time I needed the bathroom it would be. I keep the lift chair transformer on the edge of a book shelf at my elbow. Since I don't trust the chair not to eat my back up batteries, I keep the (2) 8 packs of AA rechargeables separately. I was able to retrieve the back up packs, plug them in & right myself... the chair seemed to be struggling the last bit of travel...
I left the chair in a position I could get out of & disconnected the back up packs again. I did call the power company to report the outage. I keep it on speed dial...
I'm not satisfied with this arrangement. Better than nothing but doesn't inspire me with confidence.
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Re: Backup power on power recliner

Postby Burgerman » 27 Sep 2018, 22:32

Your electrical system wouldnt fill me with confidence either. In the last 22 years since my accident, we had just one power outage (ignoring a handful of flickering brownouts that caused my PC to restart). Lasted over an hour. Under 2. And everyone went mad and complained like crazy. Half the town was off. I looked from above with the quadcopter and it was dark for about 2 miles.

You can see like this at night. http://www.wheelchairdriver.com/gopro/dark.mp4
Theres even some fireworks in there somewhere. The straight line is the seafront about 2 miles away.
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Re: Backup power on power recliner

Postby flagman1776 » 27 Sep 2018, 23:22

We're a lot less civilized than you are. More spread out & rural. If the outages are brief, they're of not consequence... if you know. Prolonged outages are very different.
I need a better back up for my sleeping location.
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Re: Backup power on power recliner

Postby Burgerman » 28 Sep 2018, 03:56

You have an auto leccy start generator presumably? Today these things are pretty cheap. Kick in in seconds.

Dont know about less civilised. But definitely more spread out which is likely what causes the outages.

Plug and play, brand new. Theres cheaper, and smaller, but this is ok for a whole house unless you go mad!
https://www.ebay.com/itm/Super-silent-g ... 59123caea1
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Re: Backup power on power recliner

Postby flagman1776 » 28 Sep 2018, 16:10

I am recharging all my AA cells for my back up. It's what I have for now.

A friend has a propane powered backup generator... it cost a heck of a lot more than the imported diesel gen set. No, my generator is only a 6500 Honda, manual elect start.

My ramp construction & bath remodel comes before a new gen set.
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Re: Backup power on power recliner

Postby Burgerman » 28 Sep 2018, 19:36

A friend has a propane powered backup generator... it cost a heck of a lot more than the imported diesel gen set. No, my generator is only a 6500 Honda, manual elect start.


That will leave you stuck in your seat. Cant you rig it for full auto start on power loss? Then no need for AA cells.

I saw a freind with an almost identical one to this running. https://www.ebay.com/itm/Super-silent-g ... 59123caea1

They are pretty quiet. tarts in around 6 seconds after power out. Although super silent is claimed it is not what I would call it! You wouldnt want one in your living room. You likely wouldnt hear it in a garage at all.
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Re: Backup power on power recliner

Postby flagman1776 » 29 Sep 2018, 17:30

I'm feeling really stupid right now. The AA cells I bought a Westinghouse 2000 (Eveloop replacements). They are only 1.2 volts each! I don't know what I was thinking when I bought them. The (2) 8 AA cell battery holders give about 9.2 volts, same as the inadquate (2) 9V transistor batteries OEM backup.
This is certainly not what I was aiming for. The motor is rated 29V... Sooo, I guess my next move is to shop for different cell holders. 12 AA cells? 14 AA cells? each. It happens I HAVE enough of these Westinghouse cells.
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Re: Backup power on power recliner

Postby Burgerman » 29 Sep 2018, 17:58

The eneloop cells are designed to be charged and then can sit a year and still work. Low self discharge. And they can provide high current with low voltage drop compared to their size. And fully charged will be around 1.4V.

Those westinghouse cells are unknown 2000mA claimed basic cheap cells. They are not low self discharge, and probably dead after a couple of weeks sat doing nothing. And are likely high impedance meaning say 14v fully charged and about 5 to 7V under load. As such they are no replacement for the eneloop, even if you were to use 30 of them.

Also are you supplying power to charge these from that wall brick? If so you will likely murder them. They dont need continual power. You need to charge them at constant current, about 1 to 1.4A until the point where voltage starts to drop by 5 to 6mV and stop!

You have to know what is going on, and measure things.
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Re: Backup power on power recliner

Postby flagman1776 » 29 Sep 2018, 18:44

The chair's backup batteries set up is (2) disposable 9V transistor batteries. So no maintenance charging from the transformer.
My add on backup is sat there disconnected... I have to plug it into the back of the transformer to activate. Not the easiest, especially by flashlight but I did it.
I didn't check the voltage of the used cells before recharging. That would have been enlightening. The unused cells from the same (6 month old) batch are 1.29V. Never been charged by me.
Maybe I should run an attended test. Shut off the power strip & use the backup to rescue myself. THEN check the battery condition. The Westinghouse cells may be alright. The "slowing down" IS when the chair starts to lift which takes more POWER. It may not be a battery failure at all. Battery power can never compare to unlimited supply.
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Re: Backup power on power recliner

Postby Burgerman » 29 Sep 2018, 19:23

You need to test battery voltage AS YOU USE THEM. On load. Those cells may be crap.

Also you need to charge every 4 weeks for normal AAs. ENERLOOP are special, with low self discharge around 10x better than normal nickel based batteries. So when disconnected they are good for a year.
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Re: Backup power on power recliner

Postby flagman1776 » 29 Sep 2018, 21:19

The Westinghouse Ni-Mh 2000mAh are suggested to charge with the Eveloop charger. I think they are a simple knockoff.

The cells I ran the test with... have higher voltage (1.36V)... than the never charged ones (1.29v). I couldn't test the volts under load without rewiring & I was anxious get started.
I didn't check new charged cell voltage before I tested. I expected outcome of less than the 1.29V of an unused cell. I'll charge some others to get a fresh charged voltage. I don't think I can blame the cells.

It was slow... the lift is never fast... but it did Rescue me.
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Re: Backup power on power recliner

Postby Burgerman » 30 Sep 2018, 01:20

The Westinghouse Ni-Mh 2000mAh are suggested to charge with the Eveloop charger. I think they are a simple knockoff.

Absolutely not. And ALL rechargable nickel based AA cells can be charged with the enerloop charger.. Those cells are rubbish.

The cells I ran the test with... have higher voltage (1.36V)... than the never charged ones (1.29v). I couldn't test the volts under load without rewiring & I was anxious get started.

The voltage of an UNLOADED cell tells you nothing useful.
If you test an Enerloop under load it might drop from say 1.5V to 1.3V under load. The Westinghouse cell MIGHT do the same. But it also is far more likely to be like the vast majority of cheap AA cells, and higher impedance. So under load may even go lower than 1V. The only way to know is to measure it.

I didn't check new charged cell voltage before I tested. I expected outcome of less than the 1.29V of an unused cell. I'll charge some others to get a fresh charged voltage. I don't think I can blame the cells.

Unloaded voltage of AA cells doesent tell you much. The only thing that matters when in a heavy discharge situation such as runnig a motor to lft a human is resistance/impedance. And the only cells that seem to have any reasonable performance here are the enerloop ones. The rest MIGHT be OK but you dont know without testing. Most are crap!

It was slow... the lift is never fast... but it did Rescue me.

If the cells are high impedance/resistance then it will be slow! Or inadequate altogether.
If the cells are partly discharged, then the resistance gets higher and so even slower! And those cells are NOT designed to stay charged. Most nickel metel type cells have very high self discharge rates.

All of this is why I suggested enerloop cells to begin with.
And theres no way on earth those 2x 9v batteries could ever have worked.

WIKIPEDIA

Self-discharge
NiMH cells had a somewhat higher self-discharge rate. The self-discharge is 5–20% on the first day and stabilizes around 0.5–4% per day at room temperature.

Low self-discharge
The low self-discharge nickel metal hydride battery (LSD NiMH) has a significantly lower rate of self-discharge. The innovation was introduced in 2005 by Sanyo, under their Eneloop brand. By using an improved electrode separator and improved positive electrode, manufacturers claim the cells retain 70–85% of their capacity when stored one year at 20 °C (68 °F). They are otherwise similar to other NiMH batteries and can be charged in typical NiMH chargers. These cells are marketed as "hybrid", "ready-to-use" or "pre-charged" rechargeables.

Separators keep the two electrodes apart to slow electrical discharge while allowing the transport of ionic charge carriers that close the circuit during the passage of current. High-quality separators are critical for battery performance.
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