North Australian FISH FINDER forums

Been a while since I was on FFF and there's been a few techo changes in some of the equipment.

Probably the most significant is the development in lithium battery technology.

Like anything to do with batteries, confusion can be widespread.

In the case of lithium batteries, early technology seemed to invite people with a suicide wish to embrace lithiums due to "thermal runaway" when charging and resulting fire/explosion.

Confusion within industry players' terminology didn't help either. Just like that with lead acid batteries.

here's something that might assist anybody contemplating changing to lithium.

There's also a link to a manufactuer's site explaining (pretty well) the dangers of charging a lithium battery straight from a o/b alternator. https://www.victronenergy.com/blog/2019 ... g-lithium/

On the Victron Enery link is a informative video about lihium charging and alternators.

Having recently switched to lithium (12 months ago) in my boat (and car) I found this interesting and good information . I ended up settling on BCDC 25A charger to limit the current from my Yamaha 35A alternator. After watching that Victron Energy link I am glad I have set it up the way I did. I use both Victron and Redarc stuff and very happy with both. Have seen and heard some nasty stories about some of the cheap stuff on the market.

Glad u found the info of use.

You'd already taken the plunge so I guess the info was reassuring.

For anybody thinking about lithiums, be aware that it'll probably be the same suppliers who spread so much confusion about lead acid types who'll be selling lithiums. The saving grace is that the tricky bits thrown up by lithiums are a lot less than than the confusion thrown up by lead acid technology.

You might say that there are fewer tricky bits to confuse average Joe Battery retailers (who in turn confuse their customers). The newer breed of younger guys involved in lithium technology seem to be a lot more switched on than the traditional retailers.

However, the main thing to look out for is the charging arrangements/alternators. Be aware that some of these suppliers/manufacturers/retailers still think ordinary standard alternators are OK with lithiums.

For larger boats with 24,36 or 48v electric o/boards, the savings in weight alone are very significant compared with lead acid types.

On that XL sheet, it works out how long approx your lithium battery will stay above 80% depth of discharge. U just need to put entries (current draw of whatever u use in the boat) into the yellow squares.

Yell out if u want the actual live XL calculator.

I was considering getting a Lithium starter battery for the car when the time comes to replace the Optima yellowtop that I have at the moment. I assume that the BMS in the newer generation Lithium batteries are compatible with the smart alternators in current vehicals?

My advice is never to assume anything about what may sound logical particularly with anything electrical.

Modern vehicles since about 2016 are usually fitted with "variable voltage alternators" which are designed to improve emission standards. As a lead acid battery charges, the vehicle computer (CPU) varies the alternator voltage to reduce the engine load thus improving efficieny.

If that's what u mean by a "smart alternator" then I wouldn't consider a straight lead acid starter battery swap for a lithium starter battery as in your interests.

A lithium BMS (battery mangement system which is internal in the battery) manages the battery NOT the alternator.

II'd be looking at a dc/dc charger on the output of the alternator to charge a lithium starting battery safely.

Some terminology for dc/dc chargers is "regulators". Essentially a "regulator" for that instance will include a dc/dc charger as well as performing other functions. Loose use of inadequate or non-specific terminology has caused almost as much grief as assumptions.

Don't just take anybody's word (including mine). Go check out some responses from 3 potential suppliers.

I should mention I haven't used lithium for cranking in either boat or car. Kept the old faithful lead acids for that job. Everything after the cranking batteries is lithium controlled by DCDC chargers and monitoring. 240/12V plug in charging at home.

Ditto here. A 100 ahr lithium for the electric with separate 240v charger and a l/a for cranking.

Charging lithium not as fast as I expected but still heaps faster than l/a. The older 120ahr electric l/a took a long time to charge as its discharge was much greater.

U using 12v or 24v (mebbe 36)? I thought u had a fair sized boat hence the question.

I've stuck with 12V as my boat's only 4.9m. 200ah house battery (fridge and electronics) and 100ah dedicated for the minn kota. Plenty of power for overnight trips but I take a small 1kVA genset for the bigger trips.

ronje wrote: Sun Mar 17, 2024 11:35 am Ditto here. A 100 ahr lithium for the electric with separate 240v charger and a l/a for cranking.

Charging lithium not as fast as I expected but still heaps faster than l/a. The older 120ahr electric l/a took a long time to charge as its discharge was much greater.

U using 12v or 24v (mebbe 36)? I thought u had a fair sized boat hence the question.

Hey Ronje, how many amps are charging the lithium with? Does it fully charge overnight?. Was thinking about changing to lithium from my AGM.

Sullo
I'm using a lithium 240v charger @17 amps. Can get higher amperage chargers if you wish. Usually charges in 6 hrs so o/night no trouble.

Remember that you don't need a lithium of same Ahrs to do the same job as a lead acid (which is what an AGM actually is).

1/3 of the weight as well.

Weight advantage really good for qwners of larger boats with 24 and 36v systems plus because as u go up in voltage, the current draw is less.

example: 48 ahr = 4 amps @ 12v but it also equals 48 ahr = 2 amps @ 24v. Less amps for same job so the ahr capacity need is also reduced even further.

Question " will I change to lithium"? should really be " why haven't I changed to lithium"?

Because of the weight reduction we should start seeing 24V electrics in smaller boats. THEY'LL hold position in run-off or tidal run.

I've had lithium for a few years now. It takes 3 days hard fishing to run them flat on my 24v minn kota.
I've bought a victron 12-24 for long trips but I'm afraid of damaging my alternator (30A on a Yamaha F80BET) so I'm too chicken to hook it up. I can't see any way of manually limiting the amps I want it to draw and the video above makes me think it will try and draw too much. The unit I have (orion 12-24 10A) is mentioned in the video as an upcoming product but doesn't say if it alone is suitable to avoid this issue. I know Richie off this forum has a flash new setup with something sophisticated in it to mitigate the risk to the alternator and rectifier

Do you have yr alternator running to both yr starting battery AND to the Orion dc-dc converter? If so, what type is the starting battery?

The two things about lithium BMS harming alternators are overheating and "load dumping". If BMS suddenly disconnects the battery while the alternator is supplying significant current, voltage spikes will usually occur and the alternator will be sorely tested. Its not a case of the alternator harming the BMS. Its the other way around.

What happens with the introduction of new technology like lithium is that users don't know enough to ask the right questions. It took me a while and I worked in a similar industry. Hence a lot of confusion ensues and the one thing that the lead acid industry clearly showed over years was that retailers were some of the most common spreaders of confusion.

I asked about the type of starter battery 'cos a lead acid starter battery in parallel acts as a "buffer" for the alternator. It "smooths out/absorbs" the effects of any variations coming from the lithium via the BMS (like load dumping).

Orion dc-dc charger is a brand sold by Victron. I don't know if Victron makes 'em or if its one they endorse. It may be that the Victron charger is an Orion. If its got a lithium profile output then it should be ok.

Best advice is to talk to Victron and not the local dealer.

At least you're adopting a "be sure" approach.

I have found a couple of manufacturer's who sell Lithium starter batteries. They both say that the BMS systems will handle the smart alternators.
Will look into them further when the time comes to replace mine.

Sullo

Sorry. I misled u. Its a 240v/20A lithium charger that I've got.