What about using lithium for starting

[John Simmons]

I am in the midst of replacing my 800Ah 12V AGM house sell bank with 40 of the fortune 100AH Cells. 10 cells as a parallel set, then each set in series For a total of 1000 Ah at 12V. The BMS I am using will be the Electrodaucus because I did not want to chance having the power suddenly die if the BMS craps out, which is the case if you use a FET based BMS. I am a live aboard, and all of my charging systems can be reprogrammed for Lithium including the Balmar regulator. Charging and battery monitoring is all done and taken care of, no worries there.

The idea of going completely to all fortune cells for a separate start bank rather than the gel/agm cell sounds Very attractive.

Start loads would be either the 6.5kW northern lights 3 cylinder diesel, or the 59hp Volvo diesel. Neither of these are big motors. The starters are TINY, we are not talking about a 500 hp Detroit Diesel. I was wondering if it might make sense to make a starting battery bank out of 8 other fortune cells, 12 V 200 Ah, but this time NO BMS. I have all remote meters and can switch charging sources from alternator, solar, or generator. Is there ANY reason not to use the lithium batteries for starting?

I have read that a normal car start motor is around 1 hp, so that makes it 746 watts, let’s say 1 kW. At 12 volts that is only Amps, and for only a few seconds.

Am i missing something? The 8 cell fortune bank should not have a problem at all with that.

Thanks in advance for any feedback.

John

 

[Craig]

The fortunes have a 10C discharge rate for a few seconds so I do not see why it would not work well.

 

[greyghost]

John, what @Craig said.

Like you, I am replacing a large house bank of batteries with Fortune cells, most likely 60Ah cells in a 3P4S configuration of discreet 180Ah 12V batteries wired in parallel, each with their own FET based BMS and BT monitoring. I figure this will give me reasonable insight into cell behavior so that, in the event one cell acts up, I can locate it within its own discreet battery and down to its local group of three parallel cells. This way, if one BMS or Cell fails, I can isolate the offending battery from the remaining house batteries, continue cruising, and replace the offending BMS or cell at my leisure without bringing the entire house bank down to do so.

Are you concerned that your single 10P4S bank might have to be taken off line to swap out a bad cell?

Cheers,
Doug

 

[JoeHam]

Found this today:

Blue Sea Systems Engine Starting Standards - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Best info I have found on starting loads. Seems like LFP should handle it.

That first quarter second is impressive though!

 

[bostonbuzz]

I'm doing this, but having some trouble with balancing my cells (I'm a noob). I went with an external relay BMS and am using the Bluesea magnetic latching relays that use no power at either open or closed, and can be manually set to open in an emergency. Photos here: https://diysolarforum.com/threads/discussion-cases-for-aluminum-cells.5407/post-77266

I have 4x 280ah cells, rated to only 1c, so 280amps to start my 19hp 3 cylinder diesel in the sailboat. a 1kw starter motor can easily produce double/triple the amps. As you see in the link above, the inrush current is significant. My cells don't have a rating for "peak" for a few seconds, but I'm sure it's higher than 1C for under 1s.

Lithium should be way better than LA for starting, and I think people using a combined LS/LIFEPO4 systems are not going to be doing it for much longer. It mostly makes sense now when the alternator is dumb and other charging sources aren't set up, along with having a 1/2/all switch on boats. Also having many "black boxes" of electronics between you and some dinosaur juice is not ideal, hence the manually operable solenoids.

 

[Fish Freak]

There are a LOT of people using off-the-shelf LifePO4 batteries for starting petrol engines. Some using them in cars, but I've read about many doing it in boats with a variety of outboard and inboard motors. I've done a little survey on another forum about boating, bbcboards dot net, under the General forum, and then under Electrical/wiring/trolling motor threads, plus there's a lot of info you can get about it on this forum.

I'm finding that most of the pre-made LifePO4 assembling companies like Ionic, Battleborn, etc., are only using a bms with a 100a continuous rating, yet they have the ability to provide a quick starting burst, for 3-4 seconds before the bms cuts it, no problem, of 200a to 250a. Doesn't sound like much but apparently amps from lithium tech cells are very different than CCA's for engine starting. These engines they're starting all call for MCC's of well over 1,000a, and my forum surveys show MOST are very happy with their results.

I talked to a few China lithium engineers via Ali and the best I got from them is that if you try starting petrol engines with LifePO4 batteries that aren't big enough, you stress them out and shorten their lives. For instance, a 12v 100Ah LifePO4 battery spec sheet shows it can handle a 2C discharge of 200a. Try to pull 300a or 400a from that and it'll do it, but the core, it's gonna get hot and life expectancy will go down. The engineer suggested that if I was trying to draw 350a for starting a ICE, make your crank battery from at least 150Ah prismatics, and that'll easily handle a 2C burst of 300a.

Now, there is one common problem that I've seen these guys run into with lithium starting batteries: High Voltage Disconnect. These savvy boaters will charge all their lithiums the night before going boating to 100% full. Then they'll hit the water, and 15 min into their first run their 60 to 120a alternator will push that battery to it's high-voltage limit and trigger a HVD event! What happens next is all their nav electronics connected to that crank battery shut down at full speed. The engine keeps running because the alternator provides enough amps to do so. They've got to stop their boat, wait 5 minutes for the bms' auto reset to kick in, and then run extra items like all the bilge and livewell pumps dry all day to keep from repeating the HVD cutoff. That's tough on pumps too...

So my conclusion is I'm building a crank battery with some reserve size, like my target WAS a 120Ah 12v battery, but now I'm planning a 150Ah target. Then with the bluetooth app on the bms like Will's pick, I'll set a charging cap voltage that'll put me at about 75% charged when it cuts off from my overnight A/C charging at home. When I hit the launch ramp, I'll raise the charging cap voltage to 85% or 90%, and the HVD point should never be reached.

The alternative plan would be to get a separate port bms, run the engine on the charge lead and the nav electronics on the load lead so if you hit a HVD, your nav electronics would still have power. NOTE: I'm ASSUMING that with a separate port bms, in a HVD the bms cuts the charge port and not the load port but this could be incorrect, or different depending on the mfg or design of the bms. I have NOT bench tested this idea and that's why I'm going with Plan A above first. In this alternative plan, for peace of mind I'd run a Sterling Alternator protection device so if you hit a HVD, you wouldn't smoke your alt's diode.

 

[bostonbuzz]

The alternative plan would be to get a separate port bms, run the engine on the charge lead and the nav electronics on the load lead so if you hit a HVD, your nav electronics would still have power. NOTE: I'm ASSUMING that with a separate port bms, in a HVD the bms cuts the charge port and not the load port but this could be incorrect, or different depending on the mfg or design of the bms. I have NOT bench tested this idea and that's why I'm going with Plan A above first. In this alternative plan, for peace of mind I'd run a Sterling Alternator protection device so if you hit a HVD, you wouldn't smoke your alt's diode.
[/QUOTE]

That is what I have built. Separate port, chargery BMS, bluesea latching relays. The alternator issue you talked about I did not imagine because even dumb alternators only charge to 14.2v. Over temp on the alternator is the problem I’m worried about, so I’m regulating the existing one with a balmar Mx-614. (Haven’t some that yet) a disconnect would be bad (likely from imbalanced cells) so a sterling alternator protector is required ($75).

 

[Fish Freak]

That is what I have built. Separate port, chargery BMS, bluesea latching relays. The alternator issue you talked about I did not imagine because even dumb alternators only charge to 14.2v. Over temp on the alternator is the problem I’m worried about, so I’m regulating the existing one with a balmar Mx-614. (Haven’t some that yet) a disconnect would be bad (likely from imbalanced cells) so a sterling alternator protector is required ($75).

I was thinking it's the amps that don't have anywhere to go when the BMS cuts the charges port that kills an alternator, but you're right, there's also the lack of charge resistance on lithium batteries that makes the alt think it's got a big load when it doesn't, and could get hot, and that's the other problem with lithium crank batteries. I would really like to hear what that Balmar MC-614(?) is doing for you, I see it somehow regulates based on alternator temperature but doesn't appear to have a temp probe? Only works with an externally regulated alternator, right?

 

[Dauntless]

Balmar regulators do have temp probes, but you must add them.
One of the few things LA do so well is as a starting battery. Why use a $1000 battery to replace a $90 one?

 

[Fish Freak]

Balmar regulators do have temp probes, but you must add them.
One of the few things LA do so well is as a starting battery. Why use a $1000 battery to replace a $90 one?

Three reasons I'll replace LA AGM with LifePO4:
_ Weight: critical in my application
_ Power: twice that of LA
_ Price: The large Odyssey or Northstate Pure Lead AGM's i prefer are about $400 give or take. Very dependable, reliable, and 77 lbs. I will be DIY'ing a 150ah LifePO4 and the cells, case and BMS put me right around the same price but the lifespan is 'said' to be many times greater.

I don't know yet, pencil-pushing now, I haven't done this yet, but it seems very do-able, the benefits appear to far outweigh the drawbacks. Since I can repair the battery if the bms dies, a cell dies, or if tech improves, I will keep the same battery for the rest of my boat's life. I run 4 batteries so changing to lith tech will be like rolling a dead body off the back deck of the boat, and that will get me close to my goal of 80 mph speeds. That's my REAL motivation! Lol, silly, yea but I guess those are reasons 4 and 5...?

I would never even buy a $90 dime store battery because they're an acid/electrolyte mess, cannot produce enough CCA's to crank my motor AND run accessories for a day. Can you tell me your talking points @Dauntless ?

 

[Andrew77]

Nice informative thread.

 

[Zil]

Many marine systems use a lead acid battery to protect the alternator from voltage transient in case the lithium BMS suddenly opens.

 

[Danny]

I think I will always have a $100 Costco Group 27 to start my Yanmar 3gm27 motor. There is a lot that can go wrong with BMS / relays etc that can cause your engine not to start when you are close to the rocks. I can start my motor with both lithium and SLA but the SLA is my insurance policy in case the Lithium systems fall over. Expect you lithium to not work.

 

[John Simmons]

Lead acid starting batteries are cheap in first world countries. Try buying one in Panama, the price is 3x for the same battery as in the USA, and there is no such thing as Cosco. If I was in the USA which is the land of everything, then I also would keep the hybrid lead acid and for starting, and the lithium for House loads.

There is another reason I want to go Lithium. The lead acid batterries seem to be super reliable for about three to four years. After that, they are a problem waiting to happen.

One or my dock mates here in Panama just bought two 1000 CCA batteries. They paid 600 dollars.

 

[John Simmons]

I also am using the Electrodaucus BMS, so there are no fets or relays to shut the battery down. Electrodaucus does not control the battery, it controls the loads or charging sources which to me was a clear advantage.

No power electronics to get hot, just monitor the cells, the overall battery, and if the voltage goes too high, either shut off the field current to the alternator, turn off the battery charger or the solar charge controller. The battery always stays in the circuit, only the supplies and loads are disabled. A far more elegant solution than removing the battery from the system.

 

[toms]

A small LiFePO4 cell in parallel with a supercapacitor is the best starting battery combination.

 

[Danny]

I also am using the Electrodaucus BMS, so there are no fets or relays to shut the battery down. Electrodaucus does not control the battery, it controls the loads or charging sources which to me was a clear advantage.

No power electronics to get hot, just monitor the cells, the overall battery, and if the voltage goes too high, either shut off the field current to the alternator, turn off the battery charger or the solar charge controller. The battery always stays in the circuit, only the supplies and loads are disabled. A far more elegant solution than removing the battery from the system.

With sbms0 you can decide to keep your battery always connected on shut your charge /discharge sources down and I will have a auto battery switch that will shut off my house bank as a backup fail safe for house. I’m just afraid of depending on a home built battery pack to start my engine until I have more experience at sea with this LiFePO4 technology. I also like being able to quickly source a starting battery at Costco and the warranty is excellent. I don’t think I really trust my DIY design with my life until I had a few more years of experience.

 

[John Simmons]

The batteries are in. I am temporarily keeping the lead acid starting battery I bought in Colombia a year ago. When it dies, I will decide at that time what to do.

Currently I have two banks of LiFePho4 batteries in parallel, one 1000Ah, and the second 200Ah. They are shorted together for 1200Ah. Each bank has a balancer on it

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The 1000Ah side also has the Electrodaucus BMS controlling things. Here are a couple of pictures. There is still a lot to do, as far as programming up the Balmar alternator, the Samlex Inverter, the MorningStar MPPT controller, and runnning control wires for the Electrodaucus to shut things down. Still, at least the batteries are in, and the boat looks less like a disaster than before.

Two pictures are before installation of the panels to hold the batteries down. The third shows the end result, and just for fun I threw in a couple of the disaster I have been living in for over two weeks.