Garmin GPSMAP 66 battery pack

[+The Wyners]

I am loath to buy Garmin's expensive and lower capacity  rechargable battery pack and would prefer to use the better Eneloops for recharging via USB.

I realize that there is  microswitch which is triggered by the case of the expensive Garmin pack to start the recharging  but this as far as I can see can be  replicated by using a small thin strip of plastic between the two Eneloops  to trigger the switch . Does anyone do this out there , does it work ?. Thanks all

[+ecanderson]

Yes, it's been done, and it works.  There's an old thread somewhere in that regard.  Garmin's understandable concern was avoiding attempts to recharge cells that aren't designed to be recharged, and would pose a safety hazard.  They couldn't possibly trust users to use only rechargable cells, so the work-around is necessary.

 

[+dprovan]

I came from DeLormes which allow discriminant recharging in the unit, so I considered what you're talking about when it was clear the Garmin batteries were priced to gouge. But the "safety" switch and other stern words made me think they'd void the warranty in a heartbeat if I recharged anything but their battery. It seemed like a bad idea to risk my warranty since I saw a lot of Garmins being returned for replacement when I first got mine. (Turns out my 66st has been quite reliable, so I didn't need the warranty after all.) So I just charge my batteries externally. Not bad, especially since it's trivial to open the battery bay. (It takes a more effort to unscrew the latch and get to the batteries on a DeLorme.) I do miss not being able to charge the unit by plugging it in while I'm driving, but other than that it hasn't been as big a deal as I thought it would be. In fact, I'm not entirely sure it would be less effort to have to deal with the jury rigged plastic strip to defeat the Garmin battery ID switch unless you never swap out the batteries.

[+Atlas Cached]

Please see FAQ 51 at GPSrChive > GPSMAP 66

[+mikeD]

I was involved with that old thread 2/3 years ago

I made a “cassette” which worked fine from shrink tubing with a small pice of wood crafted to fit the arcs of the batteries and  create pressure on the switch

 it worked ok

 when i first had my 66 I had an issue with the battery charger internally not “ topping out”. It kept on charging. 

 the 66 got changed  

 since then for 18 months i just use Eneloops loose. No cassette

 why

 the internal charger takes 6/8 Hours  So slow!!

 With a modern NiMh charger it will do them in an hour Or so

 I also have a USB charger which does them in 40 mins. They get hot  though But work OK

 so with 4 batteries , 2 on 2 off , I am always ok

this is a link to the Latest version of the charger

https://www.amazon.co.uk/dp/B079N8NQGY

 

there is another version slightly cheaper perhaps not as fast  which would be OK

https://www.amazon.co.uk/dp/B07CYWC8N4
 

both by EBL

Edited July 3, 2020 by robertlipe
removed referral code from amazon product links

[+Atlas Cached]

For those who are not aware, the amount of time taken to charge your GPSr batteries is directly proportional to their expected lifetime.

 

Shorter charge times = shorter lifetime.

 

Longer charge times = longer lifetime.

 

The GPSMAP 66 series can provide a full day of use on a single charge when used 'efficiently and responsibly'.

 

Even when using my Garmin GPSr  for a long day of intense operation, I may connect a USB power source during 'breaks' to top off the battery if necessary.

 

Connecting the GPSMAP 66 to a USB power source to charge the batteries overnight after a full day of use is non-consequential for most users, and extends battery life considerably.

[+Atlas Cached]

5 hours ago, mikeD said:

 the internal charger takes 6/8 Hours  So slow!!

 With a modern NiMh charger it will do them in an hour Or so

 

You correlation of 'faster charge times' with 'modern devices' is like comparing apples with oranges.

[+luvvinbird]

I have several Garmin GPSr's that can be recharged with the batteries in the device. Three units are still under warranty so I decided to use the Garmin battery packs on those three, but then decided to outfit the others also. For me, it's peace of mind knowing that I'm using and charging what Garmin is recommending. Also, I was concerned that there might be moisture leakage through the back cover due to a "thicker" battery, as a result of being elevated ever so slightly when using a plastic "shim" to defeat the switch. That was reported here in these forums. Finally, I like charging them in my car as the majority of my geocaching consists of driving from one cache to another and at day's end I can plug in. Needless to say, I carry spare Eneloops and still have a few plastic shims, lol. I paid $24.95 CDN ($18.95 US) for the battery packs at GPSCity.

[+ecanderson]

8 hours ago, Atlas Cached said:

For those who are not aware, the amount of time taken to charge your GPSr batteries is directly proportional to their expected lifetime.

 

Shorter charge times = shorter lifetime.

 

Longer charge times = longer lifetime.

Uh, no on that.  

Long charge times (low current) can cause a miss of the -dV point, which is critical in getting the optimum charge, along with the corresponding temperature change, which the better chargers detect as well.  Let's assume a 2200mAh cell.  (A a charge current of 220mA, or 1/10 of that, is referred to as 0.1C).  Many slow chargers provide 200mAh charge capability, which is even less than 0.1C.  NiMH really shouldn't be charged at anything less than 0.3C for assured detection.  If you have 2200mAh cells, I would recommend using no less than the 500mA setting commonly available on a Maha or La Crosse chargers.  You'll find articles on this topic in many places - some consumer, and some engineering based.  Many sources refer to 1/3C as being a sweet spot for a decent charge without reducing the charge cycles of the cell.  For a 2200mAh cell, that would be most closely the 700mAh setting some chargers provide.  It's what I use on my La Crosse.

 

The high end is set, as much as anything, by cell temperature.  A good charger will detect rising cell temperature properly and avoid trouble, but starting at a reasonable charge current is also important. 

 

In any case, it's important, if you care about power and life, to use a good charger that properly detects the charge curve of the battery and stops it at a good point.  MANY consumer units can't really do it.

 

 

[+Atlas Cached]

    

10 hours ago, ecanderson said:

Uh, no on that.  

Long charge times (low current) can cause a miss of the -dV point, which is critical in getting the optimum charge, along with the corresponding temperature change, which the better chargers detect as well.

 

You are arguing about the quality of the charger here, not the charge time. A quality charger always trumps a cheap charger.

 

In the post I was responding to, the user suggested only 'modern' chargers can charge batteries in an hour or less:

 

On 7/1/2020 at 5:47 AM, mikeD said:

the internal charger takes 6/8 Hours  So slow!!

 With a modern NiMh charger it will do them in an hour Or so

 I also have a USB charger which does them in 40 mins. They get hot  though But work OK

 

2500 mAh is a common capacity for many popular NiMH AA batteries.

 

To charge these batteries fully in an hour would require an average 2500 mA charge rate during that time span, which is not going to be healthy for the battery.

 

To charge the same batteries in 40 minutes would require an average mA charge rate of nearly 3800 mA. Ludicrous! 

 

So, Yes.

 

As a general rule of thumb, using quality charging equipment, and all other things being equal, longer charge times will result in longer battery life, and vice versa.

 

Yes on that.

 

10 hours ago, ecanderson said:

In any case, it's important, if you care about power and life, to use a good charger that properly detects the charge curve of the battery and stops it at a good point.  MANY consumer units can't really do it.

 

I would actually suggest 'most consumer units' do not do this.  Probably less than 10%.

 

Both Maha and La Crosse brand chargers are excellent choices, but even then, not all units are equal.

 

[+ecanderson]

1 minute ago, Atlas Cached said:

 2500 mAh is a common capacity for many popular NiMH AA batteries.

 

To charge these batteries fully in an hour would require an average 2500 mA charge rate during that time span, which is not going to be healthy for the battery.

 

To charge the same batteries in 40 minutes would require an average mA charge rate of nearly 3800 mA. Ludicrous! 

 

So, Yes.

 

As a general rule of thumb, using quality charging equipment, and all other things being equal, longer charge times will result in longer battery life, and vice versa.

 

Yes on that.

 

 

I would actually suggest 'most consumer units' do not do this.  Probably less than 10%.

 

Both Maha and La Crosse brand chargers are excellent choices, but even then, not all units are equal.

 

The 'popular' cell here seems to be the Eneloop, which most typically seem to come in 2200mAh sizes.

 

Yes, a 1 hour charge is a bad plan.  That would be a 1C charge.  Even shorter is worse!  I agree.

 

My comment was to explain that 'low and slow', which even the better chargers offer (e.g., my LaCrosse with its 200mA default), is NOT a good idea for a couple of different reasons.  Bumping these up to 700mA is, OTOH, a much better charge rate for a 2200mAh cell.  So while I fully agree that these fast (40 minutes!  Yikes!) chargers will inevitably shorten the useful charge cycles for a cell, I do not agree that "longer charge times" is a universally good idea.  There's a limit at BOTH ends of the spectrum that should be observed for best results.

 

Regardless of the capacity, it is a good idea to multiply the NiMH cell capacity by 0.33 and find on the charger the closest charge rate to that number that is available.  So for a 2500mAh cell, it's closer to 833mA, but there's usually no setting of that value available.  At best, the good chargers will usually give you 700mA or 1000mA.  Obviously, on the cheaper consumer chargers, there's no ability to set anything, so you (unfortunately) get what you get.

 

 

[+ecanderson]

10 minutes ago, Atlas Cached said:

 I would actually suggest 'most consumer units' do not do this.  Probably less than 10%.

Agreed.  If the charger does not at a minimum provide for setting the charge current, it's probably not going to do a very good job.

You would at first think that one that just pumped out 700mA would be OK ... until you realize that they also have mechanically separate AAA contacts wired in parallel with the AA contacts, and that these cheaper chargers have NO way of knowing what you've inserted, so must inevitably use a current that is either bad for AAA capacities or AA capacities.  Not good.

[_Art_]

It is stated in the manual (p2) that charging a non-Garmin battery pack can damage the device and void the warranty... 

but it beats me how they’d ever know unless the batteries actually leaked or something.

 

[+Hynz]

I have an Oregon 600, no original battery pack but occasionally I use the plastic-card-trick to charge my Eneloops. It works OK.

Question: When using the original battery pack does the Oregon stop charging when full and does the blinking display then stop moving?

Using Eneloops with plastic card so far I never saw the display stop moving.

 

I also have the gut feeling that charging the two batteries (obviously with the same current in serial) is quite a strain for the batteries (Oregon can get quite warm) and the charged batteries rarely last as long as being charged with a modern charger.

[+Atlas Cached]

2 hours ago, Hynz said:

I also have the gut feeling that charging the two batteries (obviously with the same current in serial) is quite a strain for the batteries (Oregon can get quite warm) and the charged batteries rarely last as long as being charged with a modern charger.

 

I remember calling tech support over this very issue, and they said it was 'normal'. 

 

My Oregon 6x0 battery pack also can get very warm to the touch while charging, so much so that I would remove the cover when charging overnight.

 

My observation has been that my Oregon 7x0 units and GPSMAP 66 do not get anywhere near as warm during charging, so I suspect they have made improvements in this area with newer models.

 

May be time to do some FLIR testing....

[+ecanderson]

If anyone is interested in measuring, the highest temp that should be allowed on NiMH to assure a reasonably long life should NEVER regularly exceed 113F (45C) -- or ever, if possible.

 

[+Hynz]

23 hours ago, Atlas Cached said:

My Oregon 6x0 battery pack also can get very warm to the touch while charging,

Could you please tell if the blinking/moving charging logo indicates when the battery pack is fully charged.

Is it different between 6x0, 7x0, 66?

[+Atlas Cached]

1 hour ago, Hynz said:

Could you please tell if the blinking/moving charging logo indicates when the battery pack is fully charged.

Is it different between 6x0, 7x0, 66?

 

That information (and much more) is available at GPSrChive > Oregon 6x0 > Operation > Power Sources > Battery Display.

[+Atlas Cached]

On 7/7/2020 at 9:07 AM, ecanderson said:

If anyone is interested in measuring, the highest temp that should be allowed on NiMH to assure a reasonably long life should NEVER regularly exceed 113F (45C) -- or ever, if possible.

 

 

You mean like this?

 

Oregon 6x0 with Amazon Basics NiMH AA:

 

 

113°F was the maximum temperature recorded over a period of several hours. Most of the time, the max temperature was closer to 100°F.

 

 

Edited July 8, 2020 by Atlas Cached

[+ecanderson]

Love it!  Was that a twin cell pack in a Garmin unit, at max temp?  If so, they're following the guidelines ... just ... to achieve fastest legit charge.

 

[+Atlas Cached]

Updated previous post with device/battery info.

 

I have been watching an Oregon 7x0 and Oregon 6x0 most of the day, and they both top out at 113°F - usually lower, never higher.

[Liviticus]

My experience with the batteries in my  Garmin gpsmap 66st is mixed.  I began using name brand rechargeables and then charging them externally. They would only last about a day. I switched to brand name non rechargeable Lithium batteries and they lasted for multiple days, but very expensive. I then bought the Garmin brand battery pack. They also last about a day. However I do like having the option to plug in the gps through USB in my vehicle and charging the unit in route to the next cache.  After all is said and done, I like being able to charge the Garmin battery pack in my vehicle but if I were out in an isolated area away from civilization where I REALLY relied on the GPS, I would have back up lithium batteries in my pocket.