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[richardistone]

Hello

My first post! I've scanned through the content on here - fantastic, loads of info! Despite reading lots on the subject, can you please confirm my suspicions regarding the battery I received with an eBay purchase - sealed lead acid batteries are a whole new ball game for me having only experienced NiCad and NiMH AA cells in the past.

It's a Yuasa 6v 1.2Ah sealed lead acid battery, no idea how old, when it was last charged or how well it's been looked after in the past. It came with a "JP Automatic Charger", this says it's for 6v lead acid battery and charges at a rate of 500ma. I calculate therefore that a full charge should take 2.4hours.

When I first received the boat I popped the battery on charge for about an hour (had not calculated the charge time at that point), installed it on the boat and had everything working fine out of the water.

The test tank at home was available last night having been used for it's alternative (intended?) purpose so I connected everything up. The rudder servo worked fine but I could not get the prop to turn in either direction, I lifted the boat from the water and still could not get any prop movement. Knowing that the battery could need a full charge I set it up for charging noting the time was just after 8pm. The LED lit on the charger and I thought all was well, however when I popped back to check on it an hour later the charging LED had gone out. I'll try it in the test tank again this evening but fear that the battery may have already lost it's charge, does it sound like I've got a duff battery?

Thanks in advance

Richard Stone

[Tug-Kenny RIP]

A voltage meter on the terminals will tell you everything you need to know. First test the battery by itself then when under load with the motor.

regards

ken

[andrewh]

Hi, Richard

As ken says a voltmeter will tell you what is going on.  Do you have one? 

If not how about a bulb from a car or similar - preferably somethoing like a sidelight bulb.  This will light at 6V, but not very brightly so it tells you if you have voltage there

Does it light if you connect it across the battery?  No? then battery possibly dead, so give it a charge and try again
Any light?
Yuasa are in the very top line of lead batteries - but even they can die if stored discharged or frozen

do you have any Nicads at about 6V?  (4 or 5 cells)  if so suggest you try them in the boat (in the DFTF) to check you don't have a seized or sticky mottor or prop shaft.

please let us know how you get on
andrew

[richardistone]

Thanks for your suggestions, will try again this evening.

I do have a digital multimeter so no problems there.

Can put together a NiMH pack if necessary.

What is DFTF (I suspect it's a "clever" abbreviation for a bath?)

Thanks

Richard

[Martin (Admin)]

DTTF = Domestic Test Tank Facility ???

[richardistone]

OK, back at home we find...

Battery before connecting up - 5.4v
Battery connected to boat wiring - 4.2v
With motor running in air - 3.0v
Disconnected from boat - 5.2v
On charge - 7.3v

Will check voltage again once the charger light goes off

Motor is a MFA/Como RE360 with a spring coupling to the prop shaft, ESC is a M sonik 3

[richardistone]

After about 45 minutes the charge light on the charger is already off. Having disconnected the charger the battery now reports 6.4v

[john s 2]

6.4v sounds better.i suggest that you check the voltage again after a few hrs, as a freshly charged battery can show a higher voltage when just charged.Unless your boat is small its unlikely that a small capacity battery will last long.What size is your boat?Also what motor and prop are you running?This infro will help the lads advise further. John

[richardistone]

It's about 2 hours since the battery came off charge. It's just been sitting there not connected to anything, voltage now shows 6.0v

Boat is 500mm long, displacement hulll with 40mm three bladed plastic prop.

Thanks again for all your help.

[john s 2]

Does sound a bit on the low side.I know its 6v but would expect a higher voltage say about 6.4 after standing and fully charged.John.

[richardistone]

This morning it's reading 5.8v. Sounds terminal to me! Think it's time to go for hybrid NiMH AA's, I use them in some of my trains so am used to their characteristics.

Thanks for all the advice.

Richard

[tony23]

Through experience in the past I have found sealed battery's a nightmare they must be regularly checked for capacity if left for a period as once there left low for too long you will not recover them to hold a charge I'm just going through the same process with a new boat I just purchased. Try here for another battery http://www.batterymasters.co.uk/Product-Yuasa-NP1.2-6,-6V-1.2Ah-Sealed-Lead-Acid-Battery-(L(mm)-W(mm)-H(mm)-97-25-54.51)_1743.aspx I went to Maplins for my battery's to find them selling a cheap Maplin branded battery twice the price I bought a Yuasa battery for.  

[Timo2]

Hi all

           Batteries :-   Top info on all batteries to be found  at     http://batteryuniversity.com/about/

           To buy batteries go to the best at    http://www.component-shop.co.uk/    ( in the UK )

  Hope is will help

  Timo2     

P.S.  6v - 1.2amp sounds like a alarm box battery ? Long life ,low output .

[richardistone]

Thanks again for your replies. I really think though that I'm not going to get on well with sealed lead acid batteries.

Browsing the Maplin website earlier, I can get 4 hybrid AA cells of 2100mAh rating for £6.99 (they're on promotion). OK it's going to cost a little more to get the actual batteries I need, but there is a shop in town so no delivery costs AND these cells will hold their charge for up to 12 months and can be used in high drain devices, plus I've got a good charger already.

Richard

[richardistone]

Had our first sail this afternoon, having spent a little time on the wiring loom and ballast and changing over to a 2.4GHz radio. It went well, now need to work on the detailing!