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Powertank woes ! Advice and wisdom please.

Telescope40

By Telescope40
in Discussions - Mounts

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Telescope40

Telescope40

Posted
Posted

Hi All. Bit of a tale and look]ng for some wise words. Apologies if this seems to ramble on abit.

Recently bought a CG5 GT mount from fellow SGL er. Must clarify that I know the mount is in FULL working order.

Knew that my standard SW 7 ah powertank was not going to have enuf poke to run it nicely. ( it does however run my LX90 with seemingly no issues on 12v's - hey ho).

Purchased one of these babys from maplins http://www.maplin.co...ompressor-49038. Thort i was being smart as bought the 17 ah model. ( 7 ah model is available too). A bit more juice for my money.

Got home, charged up as per instructions and the following happens. 2 scenarios.

1 - After a "full" charge ? The power gauge starts with about 13.2 volts showing. I do not use for 3 to 4 days and the reading falls away- down to around the 12 volt mark. Plug in the CG5 GT. Start alignment process and as soon as I hit goto the first alignment star - the mount stalls as if due to lack of power, just like the mount does when my SW 7ah powertank is attached to the CG5.

2 - Plug into mount immediately after a "full" charge ? Power gauge shows about 13.2 volts again - I run the alignment procedure and all looks good. Mount goes where I expect it to and I'm a happy bunny.

I then switch off the mount. Reset to home position and run the alignment process again. Once again, as the mount attempts to slew to the first alignment star, the mount stalls again as in scenario 1. Not a happy bunny.

I know scenario 2 would not happen normally " in the field" but if i knocked the mount I may need to reset the mount for goto. Also if the charger slowly loses charge over a matter of days, I will need to have it plugged in on a permanent basis just on the off chance the persistant cloud decides to clear for a nite, over my house. Plus, cannot see what use the jump start option for the car will be if the darn thing is losing power. Again will need to keep plugged in and charged up " just in case".

Really thinking I may have bought a "dud" charger from Maplins and looking to take back to " swop" for the same but new charger. Does this sound logical chaps /chapesses. These tests have been run indoors only.

I'm sure I may have missed salient points of my operating procedures. I will add updates as and when I think of em. Any wise words appreciated.

Regards as always John

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Telescope40

Telescope40

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Hi Guys. Appreciate the info. Think a trip back to maplins is due. i've copped for a Dud.

Just to clarify. Am I correct in thinking that I could use this powertank tonite for 2 to 3 hours, not charge it back up, and use next weekend again for another 2 to 3 hours without ant issues due to lack of charge period in betwwen sessions ??

Regards John

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pete_l

pete_l

Posted
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You may have got one that was returned by someone else and was accidentally put back into general stock. However, these units don't have a very good reputation and the little charger that I got with mine (although this was several years ago, things might have changed) was not a good match for the battery.

One thing that's worth knowing. The true capacity of a Lead-Acid battery depends a great deal on the amount of Lead in the cells. Lead is very heavy and a reputable (like this one) 17Ah battery will weigh over 6kg as a result - though note the price, they're expensive for a reason. I'd check the weight of any power pack you're thinking of buying. There's not much scope for the miracle of miniaturisation here :wink2: so if the size and weight are too far off ... well, draw your own conclusions.

Am I correct in thinking that I could use this powertank tonite for 2 to 3 hours, not charge it back up, and use next weekend again for another 2 to 3 hours without ant issues due to lack of charge period in betwwen sessions ??
With a good quality battery, it should hold its charge. I top mine up every 6 months or so if they're not in use and they hardly need any more juice at all.
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Islander

Islander

Posted
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Hi Guys. Appreciate the info. Think a trip back to maplins is due. i've copped for a Dud.

Just to clarify. Am I correct in thinking that I could use this powertank tonite for 2 to 3 hours, not charge it back up, and use next weekend again for another 2 to 3 hours without ant issues due to lack of charge period in betwwen sessions ??

Regards John

That will depend on the load that you have on the battery. If it's just the mount then you should be able to do that but don't let the charge drop too far otherwise you'll damage the battery. If you're using dew heaters and other accessories then recharge after every session. :)

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nightfisher

nightfisher

Posted
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Sorry to jump on this thread, just a quick question, i have bought a 26amp sealed unit to power my HEQ5 syntrek, should i charge it with a standard car battery charger, or a little 12v trickle job, the one like you recharge a cordless drill with?

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steppenwolf

steppenwolf

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Posted
should i charge it with a standard car battery charger, or a little 12v trickle job, the one like you recharge a cordless drill with?

I know that it means additional expense but I'd really recommend that you buy a conditioner like this one. I have two of these and have found them fantastic for keeping my 12v astronomy and specialist car batteries in perfect condition.

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StuW

StuW

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I can only comment on my own usage and it's never run dry yet and my sessions usually last about 3 - 4 hours. I must point out that most of that is tracking not slewing which would make a difference.

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steppenwolf

steppenwolf

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Stu's Maplin Unit looks pretty fair but heed this comment from the Maplin website:-

Please note: This product requires full charging for approximately 40 hours prior to first use. It is recommended that the battery charge level is regularly checked, and if required, top-up charges are administered in between uses to keep the spiral wound battery in optimum condition.

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J_M_Franklin

J_M_Franklin

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I would never buy one of those "Power Tank" products, they have cheap batteries in them and they are not designed for slow discharge, they are designed for instant drain scenarios caused by the jump starting of a high power starter motor on a vehicle engine.

When I go off with the scope in the Land Rover I use a couple of Optima Yellow top batteries mounted on a fold up sack truck, I have a set of connections permanently mounted on this so I can use croc clips to connect a power lead for the scope, and I have a power take off to run an inverter for the laptop. To ensure that these batteries are fully charged I use a conditioning charger as I have mounted in my Land Rover, namely a CTEK unit, see here.., The batteries are here. I also have a solar cell attached to the units to ensure they are always charged in case the Missus or the kids unplug the supply to the charger..cell is here

These batteries also act as emergency backups for flat car batteries or in the unlikely event those on the Land Rover die.(The Land Rover has twin Optima Red Tops)

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StuW

StuW

Posted
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J_M_Franklin You can't argue with the number of people using Jump Starters. For the same amount of money as your yellow tops which are 55ah, you can get a 1000ah leisure battery and a decent charger!

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Islander

Islander

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The jump starters are fine as long as you're careful to maintain the charge on the battery. Of course they aren't going to perform as well as a high capacity leisure battery but they do represent excellent value for money, provide a self contained unit with connectors, meters, etc. and, of course, can be used to start a vehicle with a flat battery too. :)

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J_M_Franklin

J_M_Franklin

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J_M_Franklin You can't argue with the number of people using Jump Starters. For the same amount of money as your yellow tops which are 55ah, you can get a 1000ah leisure battery and a decent charger!

No argument from me on that point, it's horses for courses and each to their own. I use my batteries for multiple purposes and I use my pack for jump starting various vehicles from cars to 44T Tractor Units (as I can flip a link and use them on 24V) as I used to partake in 4x4 rescue in a big way but this last 12 months have not due to work commitments.

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kirkster501

kirkster501

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I have two of these powertanks and they work great for me. The golden rule is that they must be charged after every use *without fail* - they must never be left sitting half charged for any length of time. They should be "topped up" every week even if they are not used just to keep them exercised properly. Also, you need a proper Optimate charger or something akin to that. The Maplin supplied charger is a piece of junk.

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steppenwolf

steppenwolf

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Absolutely agree that for 'our' purposes, a leisure battery is by far the best choice but the convenience of a standard 17Ah battery pack (carefully maintained - and that is vital) is compelling. Leisure batteries of this capacity don't appear to be available. My first (Maplin) jump-starter was considerably better than later units supplied by the same company and mine lasted for five years with careful maintenance and I am about to replace the battery itself with one of these which will be placed inside the original jump starter.

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J_M_Franklin

J_M_Franklin

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BY the way Stu....it's the quality of the battery. A cheap leisure battery uses Lead Acid technology and this is adversely impacted by cold weather, the Optima do not use Lead Acid, they are AGM, and are capable of working at their full capacity in very low temperatures. Also I should point out that the Yellow top has a reserve at full charge of 120ah...I agree they are vastly more expensive...but then they also last for years, my Yellow Tops are more than 6 years old and still hold a full charge...and they hold onto that charge for several months before the batteries would struggle to start a truck engine....

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Telescope40

Telescope40

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Thats guys fpr all the comments. Didnt know about the 40 hour charging note from Maplins. Thus could be the issue. The instructions only note a 15 to 20 hour charge and this is all i have done.

Got options now and some knowledge.

Regards as always John

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AlistairHowie

AlistairHowie

Posted
Posted

Just another thought ... have you considered a LiFePO4 battery like this ... http://www.deben.com/golf-batteries/golf-18-hole-16ah-lifepo4.html I know, I know, £200 is a ridiculous amount to spend on a battery, but you can read all the advantages yourself. It'll outlast two lead acid batteries, you'll get about 2000 cycles, it weighs about a quarter of a SLA, can't be damaged through over discharge and it'll provide you with a nice flat discharge curve of 12.5V all the way through until near the end where it will drop rapidly before shutting down to protect itself. If you compare the cost with a good quality SLA and decent battery conditioning charger, perhaps the price isn't so bad after all.

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Spanishfly

Spanishfly

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Am I correct in thinking that I could use this powertank tonite for 2 to 3 hours, not charge it back up, and use next weekend again for another 2 to 3 hours without ant issues due to lack of charge period in betwwen sessions ??

Yes - you should. Lead-acid batteries just left standing will normally lose 1% of their charge per day.

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