Re: Safety for Jab alternator

Jay Scheevel

The batteries that I have (EarthX) include a BMS module that will do a hard break if the voltage or current gets out of bounds and also serve to balance the charging per cell. These batteries actually have 2 BMS circuits per battery for redundancy. Nevertheless, I built sealed battery metal boxes vented to the exterior of the aircraft just in case.




From: <> On Behalf Of Pete Twissell
Sent: Tuesday, May 04, 2021 1:09 PM
Subject: Re: [JabCamit] Safety for Jab alternator


If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.

Lead acid batteries are quite resilient and will simply gas if over charged.

Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.

Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.

The last thing any of us want is a lithium fire.



On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:

Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.

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