60cx / 60csx And Lithium Batteries

[+YuccaPatrol]

I don't use lithium batteries, but there seems to be some confusion/outrage over the fact that the new X units can't handle fresh lithium batteries. Garmin states that these units are designed for alkaline and NiMH batteries on page 2 of the manual, but suggests lithium batteries for use in below freezing weather on page 91 because alkaline (and I assume NiMH) batteries lose capacity at lower temps.

 

Concerning lithium batteries:

 

What voltage to they produce when below freezing? I assume that they do experience some level of decreased capacity at lower temps, and this might be enough for new lithiums to be acceptable for the X units.

 

Maybe someone should put a 60CSX and some lithiums in the freezer and see what happens? Will the unit accept and power up using fresh frozen lithium batteries?

Edited April 20, 2006 by YuccaPatrol

[ImpalaBob]

If your 2 batteries are 3.4 volts total or above they will probably trip the overvoltage circuit and the unit will not work. Note ... this value may vary between units because of the varying value ranges of the components that make up this particular circuit. I wouldn't put it in the freezer as you might damage the Liquid Crystal Display among other things! Putting frozen batteries in the unit will introduce moisture issues .... and electronics do not like moisture!!!!! ImpalaBob

Edited April 21, 2006 by ImpalaBob

[+YuccaPatrol]

oops. duplicate post

Edited April 21, 2006 by YuccaPatrol

[+YuccaPatrol]

bob,

 

Garmin's specifications state the unit will work between 5' and 158'F.

 

My suggestion was to put the batteries in the unit and place the unit with batteries in the freezer to get it below freezing but still within operating temperature specifications.

 

Damaging the liquid crystal display or introducing moisture is no more likely in the freezer than it is when someone uses their GPSr during the winter.

 

But if someone wanted to heed your warnings which are not based on the reported specifications offered by Garmin, they could also simply freeze some lithium batteries and measure the voltage with a meter.

 

What I am trying to get at here is to determine what the voltage is for frozen lithium batteries. Alkaline and NiMH batteries have decreased voltage at low temps, which is why Garmin suggests lithium batteries below freezing. I suspect that the lithium battery voltage drops when frozen enough that the unit will not reject them, therefore confirming that Garmin's manual and specifications are not a pack of lies as has been suggested in other threads.

Edited April 21, 2006 by YuccaPatrol

[ImpalaBob]

Since I am a hardware circuits engineer .... and layout circuits for a living ... I can assure you that moisture and your unit are not compatable! The Garmin specs are fine if you take into consideration that the unit produces heat while operating. I would not try freezing my GPS ... and yes there are many LCD screens in autos that sit out in freezing conditions! The important thing is that an overvoltage circuit exists .... and each chip has a voltage operating range. You could get a selection of chips that worked fine at 3.4 volts or a selection that goes into overvoltage protection at 3.2 volts. CHEAP CHIPS have a big range swing.

 

It would make no sense to have a bleeder circuit to suck the voltage to a uesable level as that would just be a waste of that extra voltage. You might as well bleed off some voltage using a flashlight and keep measuring until the lithiums work. You can start the unit in diagnostic mode (hold ENTER and power it up)and the screen will give you the current voltage .... do so at your own risk .... but I've done it with mine many times to see the current voltage level on my 60C.

 

I use PowerMax NiMH 2500 mahr rechargeables in mine. Good luck ImpalaBob

[+YuccaPatrol]

Thanks Bob. Certainly moisture is harmful to electronics, but I can't see how a sealed unit is going to be significantly harmed by being chilled temporarily under conditions that would be very normal in the field during the cold months.

 

But to answer my own question, I contacted Energizer and was referred to some techinical information showing the voltage of an AA lithium battery at various temps. It looks like these will produce 1.5 volts or less when below freezing, so using them as specified by Garmin should not be a problem.

 

Edited April 21, 2006 by YuccaPatrol

[+team fuzzybunny]

So I guess my only question is this. Why is it that my 60csx will run perfectly fine on the 4.5v coming from the usb port on my computer or the 12v coming from cigarette lighter in my car for that matter? It seems to me that the 3.4v from fresh non-frozen lithiums would be o.k. I'm sure there is some simple answer to this but I was just wondering.

[indygpser]

I just don't understand the discussion about not being able to use lithium batteries in the 60CSx. Sure, the lithium batteries may perform a little longer in cold weather; however, I have used NiMh batteries in cold weather with good results. I'm not trying to flame anyone, but some people just need to get over it...lithium batteries are old technology...plain and simple.

[+YuccaPatrol]

Well, I agree with you indygpser . .. I don't use lithiums since they are very expensive and I get great performance from NiMH.

 

I started this thread because there has been a lot of discussion/frustration in other threads concerning the fact that these units are not designed to work with lithiums even though Garmin suggests their use in extreme cold conditions.

 

So I think that the final answer is that lithiums will work at cold temps because their voltage output will be decreased below the threshold for the over-voltage circuit. Above freezing, they won't work until they have been drained somewhat.

Edited April 21, 2006 by YuccaPatrol

[kb9nvh]

Their must be a regulator in there to convert external volages to what the gps wants to see. You normally want to avoid putting battery voltage through a regulator since the regulator will steal about 0.2 to 0.7 volts right off the top.

 

So I guess my only question is this. Why is it that my 60csx will run perfectly fine on the 4.5v coming from the usb port on my computer or the 12v coming from cigarette lighter in my car for that matter? It seems to me that the 3.4v from fresh non-frozen lithiums would be o.k. I'm sure there is some simple answer to this but I was just wondering.

 

 

Lithium anode batteries are the NEW technology and researchers are trying hard to find ways around thier limitation since they have such a high energy density.

 

I just don't understand the discussion about not being able to use lithium batteries in the 60CSx. Sure, the lithium batteries may perform a little longer in cold weather; however, I have used NiMh batteries in cold weather with good results. I'm not trying to flame anyone, but some people just need to get over it...lithium batteries are old technology...plain and simple.

[kb9nvh]

FYI

 

NiMH data sheet

http://data.energizer.com/PDFs/nh15-2500.pdf

 

Lithium data sheet:

http://data.energizer.com/PDFs/l91.pdf

[ImpalaBob]

So I guess my only question is this. Why is it that my 60csx will run perfectly fine on the 4.5v coming from the usb port on my computer or the 12v coming from cigarette lighter in my car for that matter? It seems to me that the 3.4v from fresh non-frozen lithiums would be o.k. I'm sure there is some simple answer to this but I was just wondering.

 

All 3 are different circuits with their own internal voltage converters. If the USB circuit senses overvoltage it will suspend the system and lock-up the computer until it is unplugged. I actually diagnosed this problem on a remanufactured unit Garmin sent me .... as it hung my system as soon as it was plugged in to USB.

 

Garmin sent me a new unit and some free Garmin cases for my time and trouble .... very nice of them! ImpalaBob