Bushnell Bear Grylls SolarWrap Mini

[GPSGuided]

Just came across this on Outdoor Gear Lab - Bushnell Bear Grylls SolarWrap Mini.
http://www.outdoorgearlab.com/Solar-Cha ... rWrap-Mini

Looked extremely compact and rolls up into a small roll. 5V 1A output, built-in Li battery and one USB port.
Found a place offering A$77 delivered to the door.

Any reason why this is not a good choice charging USB phone, GPS battery? Not sure if it's possible to charge NiMH AA batteries off it.

[Samma3l]

Just did a quick bit of research on it. It has a 2200mah power reserve which is pretty good for the reported weight (110g). A comparable charger I was looking at is a Freeloader Pico (800mah, 50g). This would make one Solarwrap Mini ideal over 2 Picos in terms of power storage alone.

This is definitely something I would look as using to charge a phone if I was out for a week or longer, especially as you could take it out pre-charged and top it up during the day.

The only problem I see with it is how to attach it to a pack to maximise sun exposure while walking. It has a single grommet to hang from but one bump and it could twist. Also vertical may not be the best position to collect full sun. This is not a huge issue, just something to work out. Do you know where they are available to buy?

[GPSGuided]

Thanks Samma3I for your input.

I looked around and all the eBay sellers are from the US with rather ridiculous P&H. Then found this supposedly local web seller for around $77.
http://www.fishpond.com.au/Sports_Outdo ... 9757101006

Never heard of this site before though. I would do some due diligence before committing to an order.

Otherwise I just watched a Youtube video on it and the whole panel is completely flexible. As such, I don't think it'd be hard to rig something to rest it on top of a pack.

Considering here...

[Mark F]

It looks like a nice unit but I suspect there is an error in the specs having looked at the link provided and the Bushnell site. The solar panel is not a 5 watt panel (as claimed on the Sports Outdoor site), it is less than 2 watts. The output of the unit is 5 watts (5v x 1 amp). The battery takes 10 hours to charge by solar (Bushnell web site) so the battery (2200mAh) is charging at 220mA + an allowance. If it was a 5 watt panel the battery would charge in about 3 hours.

The reason I picked this up is that I have been playing around with a flexible solar charger system and flexible cells are somewhat less efficient per unit area than rigid cells but much lighter. The stated dimensions of the unit is 4.3" x 18.5" and it looks like this is the total size, not the solar panel size. Based on the cells I have looked at this area would deliver around 2 watts maximum. This means that with care you could recharge the battery every 2 to 3 days of sunny weather. You need to decide whether this will meet your power requirements. It most probably will if you are doing shorter trips when all the gadgets start out fully charged but may not if you are out for a week or longer.

The system I have been playing with is a Powerfilm USB + AA solar charger which charges AA or AAA batteries (with adaptors) and uses them as the power vault in the system. If the sun fails you can charge USB items using AA batteries. It works with my USB charged Petzl Core battery, Steripen Freedom and Android phone as well as AA batteries in my Etrex 30.
http://store.sundancesolar.com/powerfilm-usb-aa-solar-charger/

[GPSGuided]

Thanks Mark for the detective work. Yes, not expecting this to be a fancy unit and I always apply a discount on specs with "dodgy" vendors. After a trip where my GPS's battery ran flat without alternate backup, I figured something small and light may be worthwhile. I like the link you provided too as it has AA recharging facility built-in. Ummm... Starting on an incremental price-feature hike again.

[madmacca]

It looks like a nice unit but I suspect there is an error in the specs having looked at the link provided and the Bushnell site. The solar panel is not a 5 watt panel (as claimed on the Sports Outdoor site), it is less than 2 watts. The output of the unit is 5 watts (5v x 1 amp). The battery takes 10 hours to charge by solar (Bushnell web site) so the battery (2200mAh) is charging at 220mA + an allowance. If it was a 5 watt panel the battery would charge in about 3 hours.

Mark,

I don't share your pessimism. Lithium batteries (like most other rechargeables) have a charging curve, and the last 10% takes a lot longer than say, getting from 50% to 60% charge.

lithium_charger.gif (4.16 KiB) Viewed 19953 times

Batteries are spec'd according to their delivered charge - a 2200 mAh might deliver 2200 mAh, but it will take much more than 2200 mAh to charge it. USB charging is typically at 1 A, and the Bushnell site says 4 hours to charge via USB (implying 4000 mAh to charge the 2200 mAh battery). 5W may well be the nominal panel rating (midday sun at the equator), but the difference between 4 H and 10 H charging is probably due to non-optimal conditions (cloud/haze, sun not directly overhead, etc). It probably would take 10 H to fully charge in normal conditions. But it may well serve to keep your device and the solar unit battery half charged on an extended trip.

[Mark F]

I was not trying to "knock" the unit but drawing attention to the apparent confusion on the web site between the power output from the battery (5 watts) and the power output from the solar cells (unstated on the Bushnell site). I estimate around 2 watts based on my own experiences with flexible solar cells. Check the mAh ratings and panel size for the flexible solar cells on the Sundance site and the size of the Bushnell unit. I have never seen a solar panel supplier quote a charge time based on "normal" conditions, only perfect conditions. As a rough check the ratio between charge times is 10 hours/4 hours = 2.5 which is the same as the ratio between 5 watts/2 watts = 2.5.

The 1C charge rate for the battery is 2200 mAh so is not matched by the USB charger or the solar cells. This suggests the full output from both sources is used to charge the cells throughout the charging cycle.

The real issue in choosing any charger is "Does your system capture enough power to maintain your power requirements for the duration of your trip?" It would most probably work for my power requirements other than my need to recharge AA and AAA batteries.

[madmacca]

I was not trying to "knock" the unit but drawing attention to the apparent confusion on the web site between the power output from the battery (5 watts) and the power output from the solar cells (unstated on the Bushnell site). I estimate around 2 watts based on my own experiences with flexible solar cells.

Ahh, I get what you mean

The real issue in choosing any charger is "Does your system capture enough power to maintain your power requirements for the duration of your trip?" It would most probably work for my power requirements other than my need to recharge AA and AAA batteries.

Yes, it raises an interesting question. Does the optimal design of solar charging system put the weight into a larger panel and a smaller battery, but where a lot of the power generated by the panel goes into the charging the final 10% of the battery capacity? Or is a larger battery (fully charged via USB when you start) and a smaller panel for opportunistic top-ups the better weight trade-off?

[doogs]

I just bought one of these to play with over the summer. I'll try to remember to put something up here after a few trips

[photohiker]

http://www.fishpond.com.au/Sports_Outdo ... 9757101006

Never heard of this site before though.

I can vouch for Fishpond. They source all over the place but I've never had a problem. Delivery varies depending on where the goods ship from and if the item is available. Bought plenty of books and DVDs BRays from them.

[GPSGuided]

Thanks Doogs and Photohiker.

I too ordered a unit when the fluctuating price was good (but suspect it's even better in the last day or two). As PH commented, they obviously had to source the item from somewhere and took them quite a while before they shipped the order. Hoping to receive it in another week's time. My first venture into solar panels and will look forward to the "experiment".

[GPSGuided]

Ok, Fishpond has come up with the goods and the unit was received today. Shipping is not fast but it's here. Pretty neat on first impression.

[Onestepmore]

http://www.fishpond.com.au/Sports_Outdo ... 9757101006

Never heard of this site before though.

I can vouch for Fishpond. They source all over the place but I've never had a problem. Delivery varies depending on where the goods ship from and if the item is available. Bought plenty of books and DVDs BRays from them.

Ditto. I have ordered heaps of books and things from Fishpond. If it is soourced from the USA delivery times are longer than from the UK. For most books there is no postage fee.

Some feedback on the unit would be great after you've used it a few times
I have a SolarMonkey Adventurer but the flexible panel on this looks compact and it's lighter.

[GPSGuided]

Some feedback on the unit would be great after you've used it a few times
I have a SolarMonkey Adventurer but the flexible panel on this looks compact and it's lighter.

Hi OSM, I have not forgotten. The unit has been sitting on my desk waiting for real life usage. Otherwise I have connected it to my iPhone and Garmin GPS (Oregon 650) units and can see both units accepting charging from the SolarWrap Mini. I have also fully charged the SolarWrap Mini using wall power over a few hours and saw the indicator light moving from red to green (fully charged). Have not had a chance to observe the internal battery being fully charged by the solar panel due to a lack of opportunity. Being a red or green indicator, it does not provide indication of charge progress. Supposedly, red means it's charging. At the same time, I can understand how increasing electronic display sophistication will also chew up power. Otherwise the unit feels decently solid. The flexible solar panel felt durable enough and the final bit of the solar strip has a velcro surface, allowing it to stay tightly wrapped on the roll. Although the soft plastic caps cover the USB ports on both ends and provide a level of moisture protection, for the general nature of this kind of device, I wouldn't want to use it in the rain. The caps are more good enough as a dirt/dust seal. Given the unit is locked together with 2 phillips head screws on each end cap, I wondered how easy it would be to replace the internal Li-ion battery in due course? One that I suspect is possible if one tried.

Will come back with more when I've had a chance to fully drain the internal battery and try to charge it up by solar energy alone.

[ricadam]

Any update to this, I found this the other day and am really interested in it to charge my phone while im out as well as my GPS watch

[Watertank]

I bought a goal zero guide plus 10 with solar recharging kit. It is robust. It differs from the Bushnell device in that the batteries are not part of the solar panel. This means that batteries can be taken out of GPS's etc and head torches and recharged - and the battery kit also supports recharging other devices by usb. I haven't used it extensively but the construction is robust and the design is good.

[Mutley]

Bought the bg solar unit a few months ago. The battery is quick to charge from a USB charger and when the built in battery is fully juiced, it will add about 45 percent charge to my iphone 4. Solar performance is disappointing but really not unexpected in hindsight. I had the panels in full sun for 8 hours, horizontally on my balcony, on a clear 25 degree day. (perfect conditions, which would be rarely experienced hiking) After this time I plugged in the iphone. It added 15 percent charge to the phone. So it may take 3 days of full sun, to fully charge the inbuilt battery. This time would lengthen if walking in shaded conditions. But hey, it weighs bugger all and if it hangs on the back of your pack for a week, then gives you half an iphone charge, it may come in handy. If you charge the battery before leaving, that's a full phone charge in a 5 day walk, provided there is 50 - 75 % sunshine. However, I can carry 4 AA batteries which will also give my phone half a charge. Would I buy this again ? Probably not.
A