BirdDog Posted October 28 Posted October 28 Hello All, So my Bristell is in need of a new battery, and the one in the machine is Lithium. The company that makes the battery still makes them, but now they come with a BMS, and they have advised not to use the new battery with the BMS in the Aircraft. I have done a bit of searching around the Internet, and have mixed information. I see EarthX have batteries with BMS but seem to be aimed at the aviation market. I have no room to install a standard Lead Acid, plus the knock on effects of the change to CoG etc. So I need to come up with a solution. I would love your opinions? Cheers John
Blueadventures Posted October 29 Posted October 29 A start would be what the Australian Agent and the factory recommend. 1
BirdDog Posted October 29 Author Posted October 29 Yep! Done that, and as expected, the advice was to find a battery that fit. I would not really expect the sales agent to have any further information, to be honest!
sfGnome Posted October 29 Posted October 29 From an electrical & fire safety point of view, absolutely yes, you should have a BMS on lithium batteries. However... The Ducatti regulator that is standard on Rotax engines (I'm assuming that yours is a Rotax) does not play nicely with a non-existent battery. As far as I could tell, most of the alternative regulators had similar issues (though the CARMO regulator given its design type might not be troubled - you'd have to ask them). The only one that I found that expressly stated that it was designed to continue working in the absence of a battery was the B&C PMR1D. It's a bit more expensive, and, as always, shipping from the US is a bomb. However, for that and other reasons, I figured that in my specific configuration, it was worth the money. 1
Blueadventures Posted October 29 Posted October 29 10 minutes ago, BirdDog said: Yep! Done that, and as expected, the advice was to find a battery that fit. I would not really expect the sales agent to have any further information, to be honest! Agree, absolutely piss poor not to assist regarding suitable replacement battery. Have you sent an email to the factory? If no reply, I'd email and phone RAAus tech for any assistance / advice they can give. I reckon the factory will be able to provide an answer even check with UK agent as they should be a good help. 1
BirdDog Posted October 29 Author Posted October 29 Thanks sfGnome. That's what I am reading too - and yes it is a Rotax with the Ducatti regulator. That said, I am surprised it can handle a lithium battery without a BMS, as voltages are not the same with a lead acid. I have had no issues with this current battery, but it is now getting long in the tooth, and should ideally be swapped out.
BirdDog Posted October 29 Author Posted October 29 Just now, Blueadventures said: Agree, absolutely piss poor not to assist regarding suitable replacement battery. Have you sent an email to the factory? If no reply, I'd email and phone RAAus tech for any assistance / advice they can give. I reckon the factory will be able to provide an answer even check with UK agent as they should be a good help. I don't think it's piss poor - just not their issue really - but the factory yes. I guess it would be interesting to see what they are fitting to new aircraft.
Blueadventures Posted October 29 Posted October 29 (edited) 6 minutes ago, BirdDog said: I don't think it's piss poor - just not their issue really - but the factory yes. I guess it would be interesting to see what they are fitting to new aircraft. The agent may not have an answer for you today but should chase down an answer for you as other owners will also be in need of a replacement battery in the future that's the support I give to people; hence my remark 'PP'. Hope you get a satisfactory answer and look forward to hearing what it is. Edited October 29 by Blueadventures
skippydiesel Posted October 29 Posted October 29 I have an Earth X ETX 900 battery. Great cranking power! Ducati VR packed it in at about 150hrs Hobbs. Replaced with Carmo CARR5115 MOSFIT Ducati had a dedicated fresh air cooling vent - carked it quit suddenly (no warning) Have yet to pull it apart to find out why. Carmo had six things going for it; Current best technology. No requirement for a Capacitor (left mine in-situ but not connected) LiPo compatible Low heat generation Australian agent/availabity Dutch manufacturer answered all my questions fully and promptly Price, less than half the cost of the B&C. Price similar to other MOSFET units on market. Only done about 30 hrs with the Carmo - so far no complaints😈 1
FlyBoy1960 Posted October 29 Posted October 29 Take a note from the eBike industry. You are not allowed to sell, or import one of these lithium batteries without an approved BMS system. The Guy in the shop was telling me there are recently introduced fines in place of $235,000 and or up to 10 years in jail for anyone selling these in New South Wales. I read from this that you absolutely need to have a BMS 4 1
Moneybox Posted October 29 Posted October 29 In my opinion the BMS is the problem for aviation use. I've not had the experience with lithium in the plane but I have 4x100 AH batteries in our motorhome. The output may be great, they accept fast charge but may disconnect with fast discharge. In the case of small electrical short circuit that may be a faulty device or worn wire might in usual circumstances blow a fuse or trigger a circuit breaker. With a BMS in your lithium battery it can take control and shut off all battery power. Then reconnection cannot be achieved without first removing any current draw. Of course it may be as simple as flicking off the master but still the BMS takes its time deciding to reconnect, time you don't have when suspended in air a long way from the fast approaching earth. For me it's a risk I can easily avoid by installing a good quality AGM battery. 1
skippydiesel Posted October 29 Posted October 29 Your Rotax ignition is independent of your battery circuit ie a battery/charge system failure will not make you eat dirt. Further , the cautious aviator will have fitted a back up battery system, to keep the avionics functioning for a significant period after main system has failed.😈 1
BurnieM Posted October 29 Posted October 29 (edited) A lot of LSAs have a COG a little aft of ideal. Would it not be a good idea to have a (firewall forward mounted) heavier AGM battery ? Yes, Rotaxes only need the battery to start and do not require one to run. Edited October 29 by BurnieM 1
skippydiesel Posted October 29 Posted October 29 29 minutes ago, BurnieM said: A lot of LSAs have a COG a little aft of ideal. Would it not be a good idea to have a (firewall forward mounted) heavier AGM battery ? To determine this a weight & balance assessment should be done. If the aircraft was designed/fitted out with a heavy lead acid battery, replacing it with lightweight LifePo4 may have a dramatic effect on W&B. This is something that should not be guessed at, taken lightly - proper measurement is the way to go. If space allowed, extra LifePo4 could be fitted & may come close to the weight of a single lead acid - need to check out the relative specifications.- example; Earth X, ETX 900, LifePo4, 400 CCA 2.2kg SSB Motorcycle AGM battery, 405 CCA, 6.72kg 😈
RFguy Posted October 29 Posted October 29 I would NOT put a battery in to an aircraft that is capable of disconnecting itself if it doesnt like what it sees no way also, many charging systems rely on having a battery there as not to put alot of rubbish and spikes and unfiltered charge onto the system bus.... it's a filter. Yes, some installs have a capacitor, but that capacitor has a hard hot life in the engine bay and wears out in no time, and additionaly, the capacitor is about 1/4 of what's required without a battery 2 1
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