Should I replace my planes battery?

[danny_galaga]

I'm embarrassed to say that I've been building my plane so long that I now doubt the reliability of the battery. So the battery is at least four years old now, and I've charged it maybe two or three times.

 

Thing is, it's in a pretty dumb location. Once I put the instrument panel on, it will be a real pain to get to. It's a pain now, but at least with the panel off I can see what I'm doing. Once the panel is on, the panel will probably never be coming off again. 

 

So, the battery is 'new' in so much as it hasn't done any work,but it's over four years old. Should I just play it safe and get a new new battery?

[Old Koreelah]

Probably a good time to find a better location, so you can more easily replace it.

Another aspect: are you sure where your plane’s Centre of Gravity is? After you finish the build, you may need to relocate heavy items like the battery, toolkit, tiedowns, etc.

 

What sort of battery? Many of us adopted LiFePO4 long ago, saving weight and increasing longevity. As long as your charging system is compatible, a Lithium battery fills the bill.

[old man emu]

1 minute ago, Old Koreelah said:

Are you sure where your plane’s Centre of Gravity is?

Batteries are the handiest things for adjusting CofG. Aircraft with tractor configurations often have their battery box at the rear of the fuselage to generate a Moment to offset the engine's Moment. That would help solve your access problem. The only downside is the cost of the extra length of power cable you'll need to run from the battery to the bus bar.

 

As for the continued serviceability of your current battery, I put a new, wet cell battery in my bike in September 2020. Circumstances have prevented my using the bike more than a 100 kms since then. The battery is still quite OK. The usual reason that any battery gives up the ghost is depletion of the chemicals it contains to provide electrons. If the battery has been sitting there, not losing electrons, the level of chemicals won't have changed much. Some of the slippery little devils will have jumped off the +ve terminal into the atmosphere, but there will still be plenty staying inside the box.

[RFguy]

What type of battery is it and what is the terminal voltage ?? If it has not been below 10.5V for any sustained period (weeks) , its probably fine.
 

a footnote- those deciding on battery location, consider heavy FRP non conductive cover over the terminals- consider what might happen in an accident and have say, an aluminium  panel or member squash onto the battery terminals. Now you have a fire.  I have seen MANY experimental aircraft have this flaw (in my opinion) , and some factory 24- aircraft.

Edited March 4, 2023 by RFguy

[facthunter]

Make it easy to get at if you can. I was removing one from the rear of a C-172 in my younger days and my metal watchband got red hot very  quickly.  Have a lifting strap on it.  Nev

[danny_galaga]

Guys, I've taken too long already. I've decided to not deviate from the kit. I just need to get it in the air. 

 

It is in fact a wet cell. I'll be at the hangar next week. I'll check the voltage and put him on charge.

 

You'd think I'd be able to tell YOU guys about batteries since I used to be an auto sparky 😄 But we'd basically put sulfuric acid in dry charged batteries and charge and install. Wouldn't really know what happens to the battery after that. If someone came in with a dicky battery, wed throw a carbon pile tester on it and check the charging etc.

 

Good call on terminal protection though Rd guy . The one good thing about the location is that the terminals can't touch anything else in a crash. If they could, the plane would be so crumpled I'd be dead anyway, and the resultant fire will kill two burns with one stone with a cremation 😄

Edited March 5, 2023 by danny_galaga

[facthunter]

Any VH plane I've owned had the usual aero type Lead acid battery where IF they are left flat they sulphate up. The only way to test those batteries is under load or a short fast charge from 3/4 charged to see if they will TAKE/ accept the high charge rate . It only has to be momentary. It's a good indication of capacity/condition.. Letting them dry out is not helpful but sometimes adding water (only) distilled and putting them through a few charge /discharge cycles will bring them back.. A good battery will show NO whiteness and the plates are a dark chocolate colour and light grey.  Dropping one will likely break some of the plates where they are bridged at the top.  Nev

[onetrack]

Every lead acid battery that is not being used should be charged every 3-4 mths, to prevent sulphation. But I've had a great deal of success with the Infinitum battery de-sulphator, which pulses the charge current and which reverses sulphation.

They're not an expensive device and you can either mount them with a battery installation, or keep it loose and move it from battery to battery. I keep mine loose and move it around, using it every time I charge a spare battery.

Since I've owned the Infinitum de-sulphator, I have thrown out less than half the batteries I used to. I've got a Yuasa battery that's well over 10 years old in my tractor crane, and it still keeps going with a regular dose from the de-sulphator.

 

Unfortunately, it appears the Infinitum company has folded up, and I can't find them for sale any more. This is likely due to the fact that there's been a huge onslaught of Chinese de-sulphators, and nearly all current model battery chargers now have a de-sulphating mode included in their design and selected charging cycles.

 

The first thing I do is check the flat or low condition battery voltage. If it's below about 12V, the battery is usually sulphated. Good batteries need to hang around 12.6V, or a little more.

 

Edited March 5, 2023 by onetrack

[danny_galaga]

Oh this is a sealed type so it won't have dried out. Has to be sealed because it sits on an angle in the Bushcat behind the instrument panel. In the nynja which the Bushcat is based off, it sits very handily on the floor. 

I might bitch about the location but as a sparky, I can see that this results in probably the shortest run for the starter cables, saving weight and giving more oomph. I'll never need to move it for C of G because I had to upgrade the empennage. This can only add to a rearward C of G in my mind.

 

I might have to add a brick or two under the cowling if anything 😄

Edited March 5, 2023 by danny_galaga

[kgwilson]

In that case if there is any space forward of the firewall, that is the best place for it. A simple fibreglass box attached to the firewall, foam padding on all sides with a top bungee strap to stop it moving. Best position for all heavy cables Solenoid, starter, engine earth, regulator, main fuse etc. Another good idea is to install an Anderson plug on the fuselage close to the battery so that you can easily jump start from any other vehicle if the battery is to flat to turn the engine over. This my battery installation on the firewall. The battery is 6KGs

Edited March 5, 2023 by kgwilson

[spacesailor]

'' 😄 But we'd basically put sulfuric acid in dry charged batteries and charge and install. ''

Dany I have some 6V, batteries that are dry charged .

But they do seem to be 'DRY' as in no electrolyte at all,  only forty ( yes 40  ) years old .

To throw or Not to throw ! , Now , That is a question .

spacesailor

[kgwilson]

My battery was nearly 5 years old by the time I got the aircraft flying. I just stuck it on trickle charge every couple of months. It wasn't regular as I'd forget but it still lasted about 4 years or more once flying.

[old man emu]

5 hours ago, kgwilson said:

A simple fibreglass box attached to the firewall,

If you can't fibreglass, go to a vehicle dismantler and pull one out of a car.

[danny_galaga]

10 hours ago, old man emu said:

If you can't fibreglass, go to a vehicle dismantler and pull one out of a car.

This is a motorcycle battery. I can fibreglass. I'm not modifying the kit, I need this done.

[Blueadventures]

Charge it up and take to battery shop and have properly load tested. Not good to finally finish kit and be doing early flights and find battery us. Then have to change it out which sounds an involved process.  I recon better than 50/50 chance still good.  Look forward to hearing you have flown your bird. Cheers.

Edited March 5, 2023 by Blueadventures

[facthunter]

See how long it holds a charge.  A good battery will hold for weeks. Discharging tells you something is not right. It's an aeroplane, remember and you can't just pull over and park.  The battery should not get hot either. Once an AGM battery has been hot, it's finished.   Nev

[spacesailor]

Ambiant tempreture of ' tin shed ' in summer would hit ,very close to 50°C .

I know that as I recorded a fifty in my Sydney ' tin ' garage,  later, I painted a part of the roof white , it dropped a degree or two .

AND, a Lot of my AGM batteries died  !.

And , I do mean , close to  dozen sitting as weights on the ' dinghy shed .

No more AGM BATTERIES for me . Wet / Flooded . 

Today's ambiant temps wil be 38° ish , & when I open my ' tinshed ' garage,  I'll check that temp above my work-bench .

spacesailor

[skippydiesel]

19 hours ago, kgwilson said:

I....................................... This my battery installation on the firewall. The battery is 6KGs........................

 

19 hours ago, kgwilson said:

........... a top bungee strap to stop it moving...........

...........install an Anderson plug............

 

Nice neat install.

 

That seems about right for an excellent Rotax start battery - I have used SSB batteries to very good effect for many years. Lead Acid/Absorbed Matt/Gel type motorcycle batterie's have been going up in CCA's and down in weight. The last I purchased, for my Zephyr , was (I think)  SSB VB16L-B CCA 385 - AH (20hr) 19- Weight 6.5kg - spun the 912 ULS almost as well as combustion.

 

Personally I don't like bungees in this sort of application - much prefer a  strap of almost any tightening system .

 

Be careful of your commonly available Anderson plug - it will literally fall apart, if inadvertently sprayed with hydrocarbon (petrol etc). There are chemical resistant versions, unfortunately I was unable to find any, when I did my search/purchase.

[RFguy]

And , a fully charged , unloaded  (but not on the charger) 12V lead acid AGM battery at 50 deg C would read about 12.15V 

where as at 25 deg C would read 12.6V

 

Any attempt to charge it  at high temperature, with a non temperature compensated charger would very much overcharge it

[kgwilson]

I recently did my BFR. Got the aircraft out & the battery was dead & instructor waiting. I could not jump start it, wouldn't even turn over so I went to the local battery shop & asked for a replacement for what I brought in. I got a Ritar RT12220 22 AH general purpose battery designed for UPS/EPS high discharge and recharge use with a 6-8 year design life in float service for $130.00. Weighs 5.6KGs. Spins the 3300A over flat out. I have no idea how long it will last but it was better to part with $130.00 at the time than pay for a BFR twice. There is no quoted CCA value but it states the monthly self discharge rate is less than 3% at 25 deg C.

Edited March 6, 2023 by kgwilson

[onetrack]

It will be interesting to see how the Ritar RT12220 performs as a starting battery. AGM batteries are not generally recommended as starting/automotive type batteries, due to their style of construction limiting high and rapid discharge rates.

I see where the battery has a maximum discharge rate of 220A for 5 secs. No mention of the maximum discharge rate for say, 15-20 seconds of cranking. Have you checked to see what the starter draws when cranking?

Did you also see where the specifications state a maximum charge rate for the battery of 6.6A? Have you checked you alternators amperage input to the battery when the engine is running?

Most automotive-style alternators put out fairly high charge rates after starting, to rapidly replenish the major battery drawdown due to starting.

[spacesailor]

'' Ambient temperature of ' tin shed ' ''

Sydney, outside air temp 38 & Inside closed all day Garage ! .

Just touching that 40 degree's.

Cooler than I expected my half painted roof must be working . Plus I now have ' foliage ' on the sunny side wall  .

spacesailor

[kgwilson]

1 hour ago, onetrack said:

It will be interesting to see how the Ritar RT12220 performs as a starting battery. AGM batteries are not generally recommended as starting/automotive type batteries, due to their style of construction limiting high and rapid discharge rates.

I see where the battery has a maximum discharge rate of 220A for 5 secs. No mention of the maximum discharge rate for say, 15-20 seconds of cranking. Have you checked to see what the starter draws when cranking?

Did you also see where the specifications state a maximum charge rate for the battery of 6.6A? Have you checked you alternators amperage input to the battery when the engine is running?

Most automotive-style alternators put out fairly high charge rates after starting, to rapidly replenish the major battery drawdown due to starting.

I have not checked any of the issues you mention. All I wanted was a battery at the time and it was all they had. The $130.00 was cheaper than getting the instructor back. If it dies I will let this forum know. The alternator has a maximum output of 17Amps but I don't know what the rectifier/regulator allows to the battery but my guess is more than 6.6 amps after starting to replenish the capacity lost in starting.

 

Most RA aircraft and motorbikes use AGM batteries & they seem to perform well in starting situations. 

[RFguy]

Starter pulls about 150A at 10V for a 3300  with good compressions. at oil and engine cold @ 18 degC.

[facthunter]

Good AGM batteries seem fine in the motorbike situation. But I emphasise if they've EVER been hot they are finished.  The aviation type lead acid have "no spill when inverted" filler caps and are heavy and good quality and high CCA. That covers turbulence not just aerobatics. Secure for 10G. It's the last thing you want to have falling around .Nev