Flat battery considerations

[Nev]

My plan is to use the aircraft for overnight trips off-piste, and I got to wondering what I’ll do in the event of a flat battery, particularly if off airport. My Bearhawk has a single EarthX battery, and I went with a firewall engine compartment mounting, (rightly or wrongly).

Who has had a flat battery, and how did you resolve it ?

I’ve spoken to a few local guys about it, some carry a power cell, some have a GPU plug on the aircraft, some hand-prop their plane etc. Obviously it’s less of an issue with a dual battery setup.

If I go with a power cell, I need to be able to connect jumper cables or a plug somehow. Having the battery under a seat would have made this easy, but there were other considerations. I don’t like the idea of having a cowl open during start.

Thoughts appreciated.

[zkelley2]

Relocate the battery to the cabin side of the firewall. If you used the earthX mount, you can just flip it around into the same holes. Carry something like an XP-10.

[jaredyates]

I carry the earthx jump starting battery pack. I haven't used it on the airplane yet, but have used them often in the cars, where I also carry them.

[JimParker256]

Ditto for me. That EarthX jump start is amazing. I've even used it to start the diesel engine in my heavy duty truck! Weighs next to nothing. I keep one in the plane, and one in my wife's car at all times.

Note that EarthX doesn't recommend starting anything over about 400 HP with it... so I was definitely a "test pilot" in that event.

[PaulSA]

Having a power pack with the EarthX isn't going to help. You may get started but the battery won't charge with the aircraft alternator. You need to recharge with the dedicated Optimate (or similar) charger which will reset the BMS.

[jaredyates]

I believe this is a misunderstanding, more below.

[Nev]

Having a power pack with the EarthX isn't going to help. You may get started but the battery won't charge with the aircraft alternator. You need to recharge with the dedicated Optimate (or similar) charger which will reset the BMS.

Paul is this what happens if the EarthX gets too low ?
I guess at least it’ll get started so I can fly home, and the alternator will power avionics etc.

My plan at this stage is to mount a Piper style GPU plug inside the cabin on the firewall, close to the battery location. Then I’ll use THIS to plug in and connect leads to. Probably a bit of overkill and I don’t see myself carrying all this gear with me all the time.

It should also give me somewhere handy to connect charging leads off the Optimate charger to if needed.

[PaulSA]

Yes. If the battery runs flat, the BMS shuts it off before it gets permanently damaged. One advantage over a lead acid, but you do need the dedicated charger to reset everythng correctly.

[jaredyates]

See below, needing a special charger during anormal bms protection event is not a consensus.

[zkelley2]

Having a power pack with the EarthX isn't going to help. You may get started but the battery won't charge with the aircraft alternator. You need to recharge with the dedicated Optimate (or similar) charger which will reset the BMS.

This is not really true. EarthX has a procedure. And a jump pack will work to do it.

https://earthxbatteries.com/our-batt...ttery-charging

[JimParker256]

ZKelley2 beat me to it... LOL

[PaulSA]

Are you saying that if the battery is flat (ie the BMS has disconnected it), you can connect a jump battery or power pack to reset it and start the engine and then it is OK to charge the EarthX from its depleted state via the aircraft alternator? Doesn't sound right .....

[jaredyates]

If the battery is reset per their procedure of paralleling a jump pack, and the engine is cranked, then I would have no reservations about using the alternator to recharge it the rest of the way. If the pack voltage falls below 10.5v, that indicates there is something else wrong, other than just a low voltage state, and it would not be prudent to force it.

[zkelley2]

Yes you can. It's right in their procedure on their website.
Follow that(all of it) and you're good. It would be prudent to print that and have in on board as a dead battery jump procedure should internet not be available.

[Nev]

Are you saying that if the battery is flat (ie the BMS has disconnected it), you can connect a jump battery or power pack to reset it and start the engine and then it is OK to charge the EarthX from its depleted state via the aircraft alternator? Doesn't sound right .....

My understanding is that the BMS cuts out to protect from damage. The older EarthX batteries won’t reset their BMS when disconnected, but if you remove the battery, connect a jump pack, and connect to an Optimate or equivalent charger it’ll kinda “defibrillate” it and can be charged with the Optimate.

[jaredyates]

I don't think it is anything special like defribulation as much as just beinging the voltage up enough to crank the engine and not have the BMS kicking in to protect the battery. If we are talking about a master-left-on while camping scenario, what battery product is going to behave in a more optimal way? In this scenario, I think using a jump pack along with the bms protection is going to get me out of the woods faster and easier than any of the other options.

[JimParker256]

To add to Jared's comment... There are guys on the SuperCub and BackCountryPilots forums who have NO electrical system at all, but have a starter, and use an EarthX jump pack to start their engines all the time. And there's at least one guy who uses one to power his radios as well. I PM'ed him to ask how often he recharges the jump pack (wondering how he gets away with this in the back country since he goes camping a lot), and he said his lasts at least a week, starting the engine every day and flying for roughly an hour or so (with radios on). Don't know if I would trust it quite that much, but...

[schu]

I've jump started and also hand propped an airplane. The hand prop was here: (https://www.google.com/maps/@61.3349.../data=!3m1!1e3) so I think that counts as remote. Anyway, my bearhawk might be pretty difficult to prop given that I'm using fuel injection and don't have a way to prime without the boost pump.

95% of the time when I have a flat battery it's because I left the master on, and the other 5% is alternator failure. Having a alternator failure alarm on an EFIS or a light on the dash fixes that, and for leaving the master on, I think some sort of a buzzer might be useful. An oil pressure switch wired to hold open a relay that has a buzzer on it connected to master would only buzz when the engine is off and the master is on.

I'll probably carry a jump box, but can't honestly think of a scenario where I would need one outside of the two issues (and their possible solutions) noted above

[schu]

Right, or the beacon....

[Nev]

We always left the beacon turned on at a previous job for this reason. Seemed to work well.

[AKKen07]

I like that Idea - wiring the lights to the batt. The last time a battery crapped out on me (due to carburetor problems - figure that one out!) It was on the beach of an uninhabited island in Prince William Sound. Hand propping saved the day. As a result of that experience (and because hand propping a 3 blade composite prop on a 6 cylinder engine scares me) I will have two redundant batteries in my plane, with the backup acting as a brownout battery during normal ops. That will also give me more than enough range with an alternator failure, allow for battery rotations per Bob Knuckols, etc.

[schu]

Another solution that might work (not sure about lithium batteries) is a little solar panel.

https://www.amazon.com/Upgraded-Waterproof-Battery-Charger-Maintainer/dp/B08K2T4RPH/ref=psdc_2236628011_t1_B07Y5TKMZ4?th=1

If you put that on the top of the cowl and connected to the battery, it should in theory charge a PC680 from 50% to full in 8 hours, which isn't bad for a 3lb solar panel.

[AKKen07]

As long as time of day and weather cooperate...

[EarthX Lithium Batteries]

Hello, this is Kathy Nicoson, Sales Director from EarthX, and we were requested to chime in here for clarification which we are happy to do.

In the event your battery has been fully discharged, which is similar to your gas tank being empty, it must be "refilled" or "charged" . It is important to note WHY your battery is empty first. If you have a bad cell, or you have not used or charged your battery for a very long time (typical time for this would be about a year if you don't have a parasitic draw) and it discharged to the point of not being able to hold a charge anymore, your voltage will drop and not be able to maintain a healthy voltage (above 13.2V). You do not want to jump start a defective battery, lead acid or lithium.

However, if you know why the battery is discharged, as in you left your master on, then it can be recharged a multitude of ways. The best way, if possible, is to use a plug in the wall charger. If your battery is within the past 5 years of age, if you disconnect the negative battery cable, this will automatically reset the battery and any charger that does not charge above 14.6V can be used.

If you are unable to use a charger, then you can use a jump pack or the old school traditional way of jumping a battery from one battery to another with jumper cables, to reconnect the BMS and add the needed cranking power to turn your engine over and then your alternator charging system can recharge the battery. I would recommend taking perhaps 15 minutes where the voltage is at 13.9V-14.6V before take off to give the charging system time to start charging the battery but if a bear is on your tail, you certainly can take off immediately.

We do have a brand new jump pack that is 12V or 24V, and can jump start just about anything from Diesel trucks to a 550 Continental engine. We also have quick connect cables that can be permanently attached to your battery that is 2 or 4 feet in length for easy access and is designed to work with the jump pack.

I hope this helps. The manual at www.earthxbatteries.com is 30+ pages long and we do try and address questions or concerns there and we do provide a lot of information on our website if you are wanting to be more familiar with the EarthX brand. Thank you!

[AKKen07]

Thanks for the information!

[JimParker256]

I thought I had seen those quick connect cables on your site... That's what I'd like to put in my plane. Guess I need to order a set!

[Nev]

Having a alternator failure alarm on an EFIS or a light on the dash fixes that, and for leaving the master on, I think some sort of a buzzer might be useful. An oil pressure switch wired to hold open a relay that has a buzzer on it connected to master would only buzz when the engine is off and the master is on.

Excellent ideas Schu.

[alaskabearhawk]

Hey All...

Just FYI about EarthX batteries that I think all should know. I bought a new EarthX ETX900 four years ago at the trade show in Anchorage. I also bought the fancy Optimate charger that is specifically for that type of battery. I'm putting my instrument panel together and I thought I should get the battery charged up and use it to power things up. I connected the charger, it went through its diagnostics and...nothing. I unplugged the charger to reset and tried again. Nothing. I measured the voltage of the battery and it was .208. I called EarthX to see if the battery could be rescued, but Kathy at EarthX declared it dead. Over time the battery will self-discharge to the point of being junk.

I had the mistaken impression when I bought the battery that it had circuitry to keep it from self-discharging. It is true that if you leave a master switch on the internal circuitry is supposed to disconnect the battery so it doesn't drop below a certain level and cause damage. But, brand new and sitting on a shelf, minding it's own business, the battery will also become unusable. Just so it's clear I'm not blaming EarthX. It is my fault. But, had I known I would have charged it periodically. Now it's just more money out the window. I'm not so sure that I'll get another. I might just declare victory and advance in a different direction...i.e. go with a PC680. YMMV

[schu]

As I understand it the BMS both prevents over discharge from being abused, but also itself draws some power. This means that you should be able to immediately recover an overdischarged battery, but also it sitting on the shelf for years will kill it.

I have a PC680 on the shelf for my cessna, and a ETX900 for the bearhawk, the ETX is waaaaaay lighter and will probably spin the prop much faster. Given that a PC680 left on the shelf for 4 years would also kill it, I'd go for another ETX.

schu

[Utah-Jay]

So is the ETX900 the battery of choice?

[Mark Goldberg]

The moral of the story is to keep it charged. About 11 lbs of weight different between the ETX and the PCA680.

[AKKen07]

I think so! I have 2 of them and even with the extra cables they weigh less than a typical equivalent.