Smart Guard 2 LIPO tester.

[Vikki]

I got three more Turnigy batteries and 2 charged perfectly but one was enough out of balance on two cells (out of 6) that by the time it was getting closeish the timeout occured. there was 0.2V in it. Sigh.

So I got one of these: Smart Guard 2 Lithium Battery Checker and Discharger | Midland Helicopters Ltd

It's great. It tells you total voltage and voltage of individual cells and tells you what you have left in the battery. Great for using on site to see if you need to increase or decrease flying time a little (or a lot). If you leave it alone for 5 seconds it will start to balance the battery.

It does this one cell at a time by gently discharging each cell down to a fixed voltage. Yep, a 6s takes all night. But! I should be able to put my battery on charge now and see if it charges properly this time.

I know my charger can discharge but the extra functions made this a good gadget for me

[Mark_T]

... and tells you what you have left in the battery. Great for using on site to see if you need to increase or decrease flying time a little (or a lot).

They are handy for sure, but take care with the % remaining function, it is only taking the voltage reading and using a generic table to estimate the result it gives.

So it is not going to be accurate for specific packs, especially genuine high C packs that are better able to hold voltage for longer, where it will show a higher remaining % than there really is.

The best approach is still to check what you put back into a pack rather than rely on this sort of measurement, but if you compare the two you can see how close it is as an estimate and then use it for easier relative comparisons.

[Vikki]

Thanks, Mark. I was planning on doing that. Neat little device, though. I usually have an elastic band on a charged battery and take it off when I put the battery in the heli. I have, on occasion, got them confused and put the tired one back in (usually after being distracted by something). Oh, dear, flight time is short

I know I've confused them but had no way to tell and with a 50-50 chance of picking the right one, well... Careful as one might be, it will happen at some point that a full one will be confused with a pooped one Love it

[nobbycopter]

These are good for marking your batteries, lots that I know use them, just put an order in for some as I've just bought 2 more batts for the 500

http://www.fast-lad.co.uk/store/char...r-p-19229.html

[Mark_T]

I'm with Vikki on this one, nothing quite so reassuring as seeing the right voltage for a charged pack on a tester or meter

I know these physical indicators work well for a lot of people, but for sure I'll slip up at some point so I always test before use.

[Vikki]

Nice looking thing there, Nobby, but it's a more sophisticated elastic band (except they don't vanish in the bag and get lost). Yep, look real nice. What do you do? Touch it or slide something? Can they be accidently changed from one state to the other? I might get some to replace my elaccy bands and use the Smart Guard as final proof. Simply because my batteries share a bag and it's easier to pull out a marked good one.

[chrissy]

i think if you got lipos a smart guard tester is a must

[cjcj1949]

1-8S Lipo Battery Low Voltage Tester Buzzer Alarm on eBay!

So many reasons to use these. Set to 3.7V for new batteries and 3.6V for old. Or anything else. Takes account of simple mistakes and allows for changes in flying style and temperature and changes in consumption due to a tight belt or a motor starting to seize. I think on load volts is more useful than the 80% rule, but there is no hard information as far as I know. I use a timer and an alarm.

[tomatwalden]

+1 on the Smart guard tester. It was only after I got one that I realised that the balance charger that came with my Blade 450 RTF helis was randomly undercharging one cell. Off the back of this (and for other reasons), I upgraded to a proper iCharger unit ...

For use out in the field, there's nothing better than doing a quick voltage check before you plug a lipo into the heli. Elastic bands etc. may work for some, but for me, it just takes a moment distraction for that to all go wrong ...

[Vikki]

When I get my batteries with a new heli I start at 4 minutes and increase the time according to how much got put back in the battery. I calculate the 80% point and work to that. If the battery has an 80% point of 1760 and I put 1200 back in for 4 minutes I divide 1200 by 4 to see how many get sucked out for a minute and dived 1760 by that to get actual minutes. I don't go straight to that. If it says 6 minutes then I will go 5:30 and re-check.

I peridoically check later on with the older batteries too. As they get used I've found that the amount drawn gets less and I can squeeze a little more time out of them. I assume this is the battery running in, so to speak.

[highlightshadow]

Only thing i didn't like about the SmartGuard2 (but i now understand why and how another tester wouldn't have helped) was using one with LiFe batteries since they hold voltage through most of the discharge.

Wish they would show the IR value also

[Vikki]

I did look at a 7-in-1 meter that showed IR but the price put me off at this time. Mostly because of the case I ordered and the trailer for my bike/trike. etc.

[nobbycopter]

Nice looking thing there, Nobby, but it's a more sophisticated elastic band (except they don't vanish in the bag and get lost). Yep, look real nice. What do you do? Touch it or slide something? Can they be accidently changed from one state to the other? I might get some to replace my elaccy bands and use the Smart Guard as final proof. Simply because my batteries share a bag and it's easier to pull out a marked good one.

You simply slide it across so yes it's a glorified elastic band lol....but as they stick on the LIPO you shouldn't lose it and they won't perish over time, or be used to wrap together loose objects to stop them getting lost, or even as emergency hair bands...but I wouldn't know about the last as I don't have much hair left these days

I use a Watt meter/LIPO checker/Balancer thingy to double check my batteries like you do Vikki...all mechanical methods rely on the grey matter functioning correctly and remembering to change the marker over. I'd like to think it was the excitement of flying that usually means I forget which battery I've already used but I suspect that it's the getting older and more forgetful that's really the culprit

[Mark_T]

Wish they would show the IR value also

IR (or ESR) isn't a static measurement on a lipo unfortunately so it takes a bit more capability than they typically build in to these devices.

[Bronek]

1-8S Lipo Battery Low Voltage Tester Buzzer Alarm on eBay!

So many reasons to use these. Set to 3.7V for new batteries and 3.6V for old. Or anything else.

Yup I use this one, permanently attached to the heli. I also attach balancing connector before attaching ESC. I normally fly until alert, not using the timer at all.