Emergency Battery 12oz.

[seastar]

Thanks Steve
Now I don't need to tip the seat (I hate that awkward job) to test the harness with an ohmmeter.
Bill

[bgillen]

In some earlier posts on this thread (#13-16) there was some discussion about lithium batteries and fire hazard that really got my attention. (Someone suggested keeping the jump start battery within reach in flight so you can toss it out the window if it started smoking!) The recommended jumper battery, the Micro-Start XP-3, seems like a great product, so I got one, along with the separate harness kit. It's a light, compact kit that looks likes it's perfect for carrying with in the CC that I'll be picking up in a couple of weeks. I also chatted with an acquaintance who is a research chemist specializing in batteries. I thought I'd pass along what I gleaned from the conversation about lithium batteries and fire hazard. In short, the fire issue is "real", but only in certain circumstances; namely over-charging the battery pack when recharging. Don't do it! And absolutely never ever try to recharge a frozen battery pack. Those are circumstances where problems might arise--for example, a battery pack left on charge for days on end in a hanger. Not good, especially a cold hanger. So, don't overcharge and don't try to recharge a battery pack that may be frozen and you will have avoided 99.9% (or thereabouts) of the risk of fire.

I also had a brief conversation with the Micro-Start folks about the harnesses--the one that comes with the power supply kit has clamps on the end of the harness, versus the harness sold separately that has round terminal fittings more likely to be left attached to the starter battery and plugged into the jumper power supply when needed. The former has small rectangular boxes in line on both the red and black wires. The latter has only a diode on the red wire--no rectangular boxes. I wondered why? Was I giving up something when using the latter? The response from Micro-Start was that the harness with clamps has, in addition to the diode found on the separately-sold harness, reverse polarity protection (the rectangular boxes) not deemed necessary with the separately-sold harness. That sounds plausible to me. Someone is a lot more likely to put the clamps on the wrong post than to put the round terminals on the wrong post and leave them that way.

Bottom line: I'm reassured on all counts and almost looking forward to my first depleted starter battery so I can use this neat little kit, along with the separate harness that I will have previously installed and left dangling from under the front seat!

[stroutmail]

EARTH X EMERGENCY JUMP PACK CHARGER is Lithium Iron which I read as being safer than other Lithium Iron. The EarthX is also available at Aircraft Spruce. It has a optional jumper adaptor that allows the same cable/disconnect to be used for maintenance charger.

The Micro Start XP3 does not mention Lithium Iron, so most times when manufacturer does not say, it is a Lithium Ion.

My little battery (Sport Cub SN 28) starts engine OK when fully charged and cold, but alternator only charges above around 1200 RPM, so pattern work and long taxi-ing at idle or 1000 RPM, battery voltage falls to 12.5 and sometimes struggles to start when hot.

The jumper battery seems like an alternative to the battery box mod.

Is there any factory advice on the cable/disconnect quick connector being permanently installed in a S-LSA???

[David H]

Stroutmail,

The Lithium battery issue is complex, evolving and improving.

To clarify: Lithium iron, is a form of a lithium ion battery. In general, the lithium iron batteries have been shown to be better for aircraft purposes than other lithium ion options.

The big advantage of the EarthX jump pack is that it is, as you mentioned, lithium iron. Most others in this form factor are lithium cobalt (like our smart phone batteries). These can often be found for $50-$60 (Costco). However, the money saved may very well not be worth it when you need your jump battery to start you when your main battery is low on charge. When cold, lithium ion batteries high amperage output falls off dramatically - especially lithium cobalt. Also, Lithium iron batteries are less prone to thermal runaway.

I purchased an EarthX jump pack to carry as a back up and wired my plane with the harness to connect the jump pack to either of my two batteries. I set this up as a two battery system (one main and one aux).

Hope this helps,

David


IMG_6649.jpg

[stroutmail]

David..looks like you have plenty of battery aboard! And a nice setup. I have little fear of Lithium Iron..stored energy whether gasoline, battery acid, or lithium all have potential dangers that must be managed.

Thanks for feedback.

I assume you are E-LSA or EAB. I am still wondering about the "harness" for S-LSA that requires factory approval for "mods".