Tracer Lithium Polymer Batteries - Beware

[GuillermoBarrancos]

Derek. Something like an Astrozap powered dew shield will consume about 1A per hour on max power setting, but considerably less than that in normal use ... say. 0.5A per hour. A CPC tracking will consume very little power as well, so all of these batteries are comfortably going to give you a night time's viewing. Obviously, the larger the better, but the good thing about them compared to SLA is that you can discharge them all the way down without damaging them

I just stumbled on this topic, but feel I had to chime in here.

It is "never" recommended to fully discharge any battery! Not even Li-Po batteries! The only difference is that Li-Po batteries won't instantly die at full discharge, but they do get damaged and their lifespan's will be significantly reduced when completely discharging them often!

It's always best practice to discharge batteries no further down to 15-20% or so, before recharching them again.

Li-Po batteries will give you the best performance when following this practice.

[FLO]

I just stumbled on this topic, but feel I had to chime in here.

It is "never" recommended to fully discharge any battery! Not even Li-Po batteries! The only difference is that Li-Po batteries won't instantly die at full discharge, but they do get damaged and their lifespan's will be significantly reduced when completely discharging them often!

Fortunately the Tracer Lithium Polymer battery packs being discussed in this thread have integrated protection against over charge and discharge. You cannot fully discharge one  

HTH, 

Steve

[GuillermoBarrancos]

Fortunately the Tracer Lithium Polymer battery packs being discussed in this thread have integrated protection against over charge and discharge. You cannot fully discharge one

HTH, 

Steve

Didn't know that. That's a great feature! I knew about overcharge protection, but not that they would have discharge protection as well. But as these batteries have a Premium price, I guess it's expected! But great nonetheless. Seriously going to consider one myself now in near future.

PS. Which they would build discharge protections by standard in all devices really. Especially mobile Phones With non-interchangeble batteries.

[keithatrochdale]

I also must add to this that there is a minimum voltage discharge level that each cell must not pass; if you do it will be difficult to charge, if it ever does and the capacity will be severely reduced. You must also watch for swelling of the cell in this case and dispose of them carefully as they can self combust and as the combustion generates oxygen water is no good, cover them in sand and let them burn. There have been a number of car fires due to charging them in the car and the normal safety advice is to charge them outside.

Another point I must make is that LiPos do not like cold temperatures and their useful capacity is greatly reduced; hence the bigger 22Ah ones will be ok but the little 7Ah ones won't. I cannot remember off hand what the reduction in useful capacity is, but it is near 50%.

They are not dangerous, but must be handled with care and operated with the suppliers guidance.

I run one of my 6v mounts off a pair of 4000MAh cells or 4Ah (with a low voltage warning) that I bought off e-bay, they work well during the day, but in the cold of night they don't last so long - but they cost me less than £10 off e-bay. I will buy another couple of packs and use them in parallel one day. That should give me 12000MAh or 12Ah which should be good; this new pack would described as 7.4v 12 Ah in 2S 3P configuration (2 in series and 3 in Parallel).

[Sp@ce_d]

Talking of swelling batteries. Been through 4 of them in Macbooks over the years.. not funny.

+1 for the 22Ah

[Astral Enigma]

I have been hovering over the "Add to Order" button on one of these for a couple of weeks and am re-assured by this thread, despite the OP's seemingly unusual experience.

I have a CPC1100 and plan to buy a powered dew shield. What I am unsure of is how many hours I could expect to get out of the 8, 10 or 22 aH versions of the power pack with that set-up.

Does anyone with experience of using these have the answer?

Thanks

Derek

Pretty much exactly the same question and thought process as I've been having! I bought a mains supply as an interim measure whilst thinking about the (large) expense of a LiPo battery - then found some scare stories, then Steve's comments that FLO are happy that there isn't a fundamental problem.

I have a Celestron AVX mount with 9.25" tube and am trying to figure out how many hours of use I'd get with a 8Ah, 10aH, 14aH supply etc - currently not running anything else BUT obviously may wish to in the future. Typically if I get two hours of vaguely clear sky it's a good night! The FLO site says output is fairly flat, so in theory shouldn't need to keepo loads in reserve just to keep the output amperage right, so do i need (can I justify?) more than 8Ah? I'll get a bigger one if there's a good case, but otherwise the extra can go towards something else. I'm assuming (perhaps incorrectly) that most power is drained whilst slewing, with less whilst it's just tracking, and slewing is infrequent.

Anyone got an experience/thoughts?

[hobsey]

Pretty much exactly the same question and thought process as I've been having! I bought a mains supply as an interim measure whilst thinking about the (large) expense of a LiPo battery - then found some scare stories, then Steve's comments that FLO are happy that there isn't a fundamental problem.

I have a Celestron AVX mount with 9.25" tube and am trying to figure out how many hours of use I'd get with a 8Ah, 10aH, 14aH supply etc - currently not running anything else BUT obviously may wish to in the future. Typically if I get two hours of vaguely clear sky it's a good night! The FLO site says output is fairly flat, so in theory shouldn't need to keepo loads in reserve just to keep the output amperage right, so do i need (can I justify?) more than 8Ah? I'll get a bigger one if there's a good case, but otherwise the extra can go towards something else. I'm assuming (perhaps incorrectly) that most power is drained whilst slewing, with less whilst it's just tracking, and slewing is infrequent.

Anyone got an experience/thoughts?

This is a very good question as I have been looking at these recently and keep changing my mind on which one to get.

[lensman57]

Pretty much exactly the same question and thought process as I've been having! I bought a mains supply as an interim measure whilst thinking about the (large) expense of a LiPo battery - then found some scare stories, then Steve's comments that FLO are happy that there isn't a fundamental problem.

I have a Celestron AVX mount with 9.25" tube and am trying to figure out how many hours of use I'd get with a 8Ah, 10aH, 14aH supply etc - currently not running anything else BUT obviously may wish to in the future. Typically if I get two hours of vaguely clear sky it's a good night! The FLO site says output is fairly flat, so in theory shouldn't need to keepo loads in reserve just to keep the output amperage right, so do i need (can I justify?) more than 8Ah? I'll get a bigger one if there's a good case, but otherwise the extra can go towards something else. I'm assuming (perhaps incorrectly) that most power is drained whilst slewing, with less whilst it's just tracking, and slewing is infrequent.

Anyone got an experience/thoughts?

Hi,

I bought the tracer 22 A/H in the end and a Lucas 22 A/H Golf Cart battery, the Tracer was £209 and the Lucas £31.00. The Tracer powered the HEQ5 pro and two Dew heaters on one ocassion and over a 4.5 hours use it still showed all the 3  Green LEDs, same with powering an Atik 428EXC @- 20c and two Heater strips.The Lucas powered 3 Dew strips on one ocassion for about 4 hours and on recharge the power indicator showed 50%. I am not going to recommend one over the other  but the information is there so you  make the decision. In my opinion  the more capacity the better and safer. The performance may or maynot vary in a cold winter night.

A.G

[D4N]

Yep that's a problem I get with anything battery powered, -20 is normal here in the winter. Lovely crisp skies but batteries really struggle.

Sent from my iPhone using Tapatalk

[Baffa]

My NEQ6 is very sensitive to low voltage, if it drops below 12v my gotos are starting to go crazy. It's a shame, I would love to get one of these batteries.

Sent from Xperia Z1 using Tapatalk.

[Astral Enigma]

I've gone ahead and bought the 14Ah version and so far used it for two evenings - about five hours in total - running an AVX mount with 9.25" SCT first night and Nexstar SE6 the second. No problems at all and it's still showing 75-100% remaining. 

Compared with running off the mains it's just so convenient - not much bigger than a small tub of butter, no cables, nothing to trip over or worry about knocking over, little weight. Yes it's quite a lot of money but so far is doing the job well, and compared with some of the other 'extras' it's just as important that the mount works, and I've got capacity in hand for if I need it... at least that's what I persuaded myself!

[DrRobin]

Hi,

Most power problems relate to one of two things, inability to supply the current (leads to a volt drop) or excessive noise (results from a badly smoothed power supply).

Noise is not normally an issue with a battery (unless you have a bad connection), but it can be on a mains power supply depending on the regulation, smoothing and technology used.  A linear psu is the smoothest thing out there, providing it has enough capacitors on the output, but a switch mode can also be quite good these days.

Most mounts and cameras etc have their own power regulator, so they take in nominal 12V and regulate it down to say 5V or 3V for the electronics with the motors been driven straight from the 12V.  Different regulators in different mounts and cameras are more susceptible to variations in voltage and I can easily see that an input of 9V is going to cause problems in some equipment when it is expecting 12V nominal.

The voltage also has to be measured under load, not open circuit and really at the input socket on the mount, not on the battery terminals.  Depending on the wire thickness, the length and how good the connections are, you could easily loose a volt or two on a cable, especially if the mount was pulling 1A or more.

The second issue is how fast the PSU/battery can supply the power or react to changes in power and this is down to the stored capacity, the Effective Series Resistance (ESR), the inductance in the system and the battery or PSU control electronics.  A mount will draw pulses of current, it might average out to 1A or 1.5A, but it might only be there for a few milliseconds and if your PSU can't supply these pulses of current without dropping the supply voltage then you are going to have problems, which might include erratic behavior or resets.

The good news is nearly all batteries/battery types have very low noise, are very smooth, have low ESR and inductance and can usually supply short peak currents with no volt drop, so it is unlikely to be a battery problem, but could be a battery power management issue or more likely a poor connection or cable that is either too thin or too long.

If the battery has a circuit to stop it been over-discharged, it is possible that this circuit is 'clipping' (limiting) the peak currents which is resulting in volt drops at the mount.  If this was the case then other users would see the same problem if using the same battery with the same/similar mount.

There might be some variance in the susceptibility between mounts of the same model to reduced voltage, either through current peaks or through low or weak charge/poor connections or a cable that is too thin, but again someone else would have seen this.

I would try a new cable, as short as possible with a thick cross sectional area and as few connectors as possible.  All because a cable works on a certain battery where the head voltage is higher or it's ability to provide short duration large peaks of current doesn't mean it will work fine on another battery with different characteristics.

Robin

[Davey-T]

Just to add my 2d to this thread, my Meade LX200 is very fussy about the power supply and I run it on it's own separate mains power supply in the obs'y, it doesn't like sharing 

I think this is more a "feature" of the electronics design rather than a power supply problem.

On the other hand I have a Tracer 40AH  battery for my portable set up which runs mount, cameras, laptop etc all night long in winter without breaking into a sweat, would highly recommend them.

Dave

[Lee_P]

The 22Ah LiPo (http://www.firstlightoptics.com/batteries-powerpacks/tracer-12v-22ah-lithium-polymer-battery-pack.html) comes with a cigarette lighter socket adapter -- can anyone clarify if this has a single socket for just the mount, or multiple sockets for other accessories as well? (A bit like this: http://www.firstlightoptics.com/astronomy-cables-leads-accessories/4-way-cigarette-lighter-adaptor.html)

[Astral Enigma]

I've got the 14Ah Tracer and it has one output, but the nice people at FLO will sell you an adapter to take up to four for under a tenner (from memory). I bought that too, but haven't yet used it. Indeed the LiPo is still on it's first charge still showing 75-100% after about ten nights out of a couple of hours each time.

[Lee_P]

Is this the adapter you mean? http://www.firstlightoptics.com/astronomy-cables-leads-accessories/4-way-cigarette-lighter-adaptor.html

Does it plug straight into the LiPo?

[Luke]

The 22Ah LiPo (http://www.firstlightoptics.com/batteries-powerpacks/tracer-12v-22ah-lithium-polymer-battery-pack.html) comes with a cigarette lighter socket adapter -- can anyone clarify if this has a single socket for just the mount, or multiple sockets for other accessories as well? (A bit like this: http://www.firstlightoptics.com/astronomy-cables-leads-accessories/4-way-cigarette-lighter-adaptor.html)

My 22Ah, from FLO (which I got last year, I think) has a single socket. I guess there are plenty of splitters around? I don't need a splitter at the moment as I only power my dob with it, though maybe I'll need one if I get a dew heater strip for the dob.

[Astral Enigma]

Is this the adapter you mean? http://www.firstlightoptics.com/astronomy-cables-leads-accessories/4-way-cigarette-lighter-adaptor.html

Does it plug straight into the LiPo?

Looks like it, and that's what they told me - certainly looks like it will do the trick!