Starting a big diesel with lifepo4

[Fuss]

Thanks again for all the replies, yes the Winston 90A is a good idea. At the moment I’m leaning towards 4 x 100a calb 3.2v cells, with a small bms, maybe 50a or even less for charging. Also I will add the ability to switch off the charging so I can keep the SOC around 50% , (well at least not 100%). Starting would bypass the bms completely. The start batteries only start and run the instrument panel so the battery does not really get cycled. I will make a second battery the same for redundancy.

[CaptainRivet]

Originally Posted by Fuss

Thanks again for all the replies, yes the Winston 90A is a good idea. At the moment I’m leaning towards 4 x 100a calb 3.2v cells, with a small bms, maybe 50a or even less for charging. Also I will add the ability to switch off the charging so I can keep the SOC around 50% , (well at least not 100%). Starting would bypass the bms completely. The start batteries only start and run the instrument panel so the battery does not really get cycled. I will make a second battery the same for redundancy.

A much better idea then LFP which can safely deliver 2C max. (expensive Winston) and 4C peak I highly suggest to look at LTO. Using a LifePo4 for starter application needs tricks eg some have small supercapacitors inside which get charged by the LFP and deliver that peak. LFP used as starters have a short life 300-500cycles unless you stay in their 2C or 4C peak rating, means a 90AH Winston can do 360A.
LTO can deliver 10C const and 20C max, they are the best starter chemistry available and even better they life 30 years + so change once and forget about them.
Get 6 or 12 cells of Yinglong 40AH and make a 1p6S or 2p6S bank out of them and put an active balancer. No BMS needed.
Was in the car stereo competition crowd for years and we tested that all out…a 40AH 1p6S LTO pack is handling my buddies 7lV8 corvette plus a 2500W competition stereo system since 4 years, no other battery chemistry made it more then 6 month in his car before, his nick was „battery slaughter“ till the LTO went in….

What wholybee wrote about the voltage sag is important too but don‘ forget the startup surge of the starter in the first 30ms…that’s killing a LifePo4 with 4C peak…unless it’s a very big bank. And that’s the next point regarding BMS, can the BMS handle that surge peak without getting fried…most have mosfets which don‘t like surge peaks at all….

Another solution use your big LFP house bank >400AH also as starter and have 2 leads just as backup charged via a DC2DC starter.
With the LFP house monitored by BMS you have a much better security and knowledge about state of your battery then before with lead and you really just need a backup in case LFP has defect. Due to charge efficiency you can also charge it quickly if getting too low.
Means run everything of your min >400AH LFP house like windlass, starter, even bowtruster (if it makes sense because of the long cable run…the only exception) and have a lead as backup in case of a LFP switch off.
There is no need for a dedicated starter anymore with LFP house.
In a catamaran you just simply have in 1 hull the >400AH LFP house/starter/windlass bank and in the other hull an LTO starter/backup bank (ultimate solution) or simple lead acid…then I would use cheap hybrid lead you ran refill that can act as starter and service. As Alternative a Optima yellow but for that money you can get the LTO right away.

The >400AH is important because most LFP cells can only do 1C constant and 2C peak and eg you have air in diesel lines and need to run starter longer you exceed the peak times, means you need to use the continuous rating of your LFP not peak. Sure if you have a very small 1 cylinder engine then starter is smaller.
I simply calculate starter watt rating x2/10= minimum house bank size. So a 2000W starter can be handled savoy by a 400AH house bank.

[ranger58sb]

Originally Posted by Fuss

To start my motor, I need paralleled 2x 12v 750 cca batteries.
Has anyone changed to lifepo4 to start a big diesel?

Why? What advantage(s) do you envision from LiFePO4 batteries in a starter situation?

-Chris

[SOLAR SUPPORT]

I think it is necessary to take advantage of the side benefits of the Lifepo4 battery investment. At least I got away with buying kitchen gas. 🙂 I feel that the time to renew the LA starter battery with a capacity of 70Ah is approaching.

That is why I am thinking of running my VP D1-30 engine with 400Ah capacity Lifepo4 service batteries. Total BMS capacity of Lifepo4 batteries is 200A. PeakCurrent capacity total 800A@10Sec. Lifepo4 batteries have 2x125A mega fuses.

I'm trying to understand if the excessive current that passes over the mega fuses for a very short time will burn them. I found a chart with an internet search for mega fuses. According to this graph, they can pass high currents for 0.1-0.5 seconds without burning up to 6-4 times their capacity.

After canceling the cable from the battery isolator in the engine room to the LA starting battery, I'm thinking of connecting the + cable from the service battery terminal of the battery isolator to the starter motor. This issue will be finalized after examining the starter motor cable connections on the engine.

[CaptainRivet]

Originally Posted by SOLAR SUPPORT

I think it is necessary to take advantage of the side benefits of the Lifepo4 battery investment. At least I got away with buying kitchen gas. �� I feel that the time to renew the LA starter battery with a capacity of 70Ah is approaching.

That is why I am thinking of running my VP D1-30 engine with 400Ah capacity Lifepo4 service batteries. Total BMS capacity of Lifepo4 batteries is 200A. PeakCurrent capacity total 800A@10Sec. Lifepo4 batteries have 2x125A mega fuses.

I'm trying to understand if the excessive current that passes over the mega fuses for a very short time will burn them. I found a chart with an internet search for mega fuses. According to this graph, they can pass high currents for 0.1-0.5 seconds without burning up to 6-4 times their capacity.

After canceling the cable from the battery isolator in the engine room to the LA starting battery, I'm thinking of connecting the + cable from the service battery terminal of the battery isolator to the starter motor. This issue will be finalized after examining the starter motor cable connections on the engine.

The first question is do the most likely present mosfets in the internal BMS survive that? If that 10sec/800A rating is correct then answer will be yes, if not what is the correct rating…well only solution here is try it and be prepared to cut the drop ins open to replace BMS.

The Megafuse won‘t blow if you have a 2kw starter but if you operate the starter longer because you eg have air in the diesel lines then they will get very hot and eg could melt the surrounding cables…Megafuses are bad as main fuses, they have very high resistance=heating up quickly and the fuses itself have very limited cooling function means they heat up the surroundings to cool down.
I would use NH0 fuses in GG (means general use cable protection) which also saves you the turn off switch as you can simply pull the fuse insert with a tool. They are made to operate at max speced rating continuously so 125A in your case but blow when you need it. You get them very cheap at the web or commercial electric stores as they are widely used in power grid and commercial applications. Also used ones on ebay work fine…I have NH3 in 630A as main fuse :-) which I bought used on ebay as these big boys are expensive. No moving mechanical parts, so as long as current goes through they are good. Connection is silver plated Cooper, best that’s available. If they are dirty just use silver polish like for your silver cutlery.

[CaptainRivet]

Originally Posted by ranger58sb

Why? What advantage(s) do you envision from LiFePO4 batteries in a starter situation?

-Chris

Use your house bank and just have the starter one as general backup.
LifePo4 has a very low resistance means the voltage drop/sag and current delivery is much better then any lead chemistry can supply.
Means the voltage and current at the starter is much higher, You will immediately realize that…starter spins effortless and that extends the lifespan of the starter significantly as the coils sees/get less amps and therefor less wear. The first that breaks on a starter is the magnetic switch, 2nd is burned through coils.
Same applies to the anchor windlass and even more as you operate it longer

[goboatingnow]

correct the Lithium bttery makes an excellent starter better then any lead

[Phil_Fr17]

Originally Posted by CaptainRivet

A much better idea then LFP which can safely deliver 2C max. (expensive Winston) and 4C peak I highly suggest to look at LTO. Using a LifePo4 for starter application needs tricks eg some have small supercapacitors inside which get charged by the LFP and deliver that peak. LFP used as starters have a short life 300-500cycles unless you stay in their 2C or 4C peak rating, means a 90AH Winston can do 360A.
LTO can deliver 10C const and 20C max, they are the best starter chemistry available and even better they life 30 years + so change once and forget about them.
Get 6 or 12 cells of Yinglong 40AH and make a 1p6S or 2p6S bank out of them and put an active balancer. No BMS needed.

+1 to you, I've had forgotten this chemistry and I agree that LTO battery can be a very good choice for cranking big diesel engine.

[CaptainRivet]

Originally Posted by Fuss

Thanks again for all the replies, yes the Winston 90A is a good idea. At the moment I’m leaning towards 4 x 100a calb 3.2v cells, with a small bms, maybe 50a or even less for charging. Also I will add the ability to switch off the charging so I can keep the SOC around 50% , (well at least not 100%). Starting would bypass the bms completely. The start batteries only start and run the instrument panel so the battery does not really get cycled. I will make a second battery the same for redundancy.

Very bad ideas and combo.
1st Calb are excellent cells for storage use, not high C use.They can do 1C and 2C peak max.
2nd bypassing BMS while drawing high current is a noGo
3rd keeping SOC at 50% when drawing high C, your bank will be out of balance after 3 starts…and dead soon.
If then use a BMS that carries no current like Electrodacus. But your Calbs won‘t have a long life, I can promise you that.
At capacities around 100AH the LTO are the only chemistry that can really survive here.

[Ballsnall]

Originally Posted by Fuss

To start my motor, I need paralleled 2x 12v 750 cca batteries.
Has anyone changed to lifepo4 to start a big diesel?

Lot of effort just to go from 2 batteries to 1.
Charge profile, alternator protection etc.

[SOLAR SUPPORT]

Originally Posted by Ballsnall

Lot of effort just to go from 2 batteries to 1.
Charge profile, alternator protection etc.

It only makes sense if an external regulator designed for the alternator is used when charging the Lifepo4 service battery bank, or if the Alternator is operated by externally controlling the operating temperature and charge voltage level using other methods.

If you have LA service batteries charged with the same alternator, plugging the fabricated alternator and new LFP starter battery into the old LA battery connectors and using them directly is also an option. You must use battery isolator.

[goboatingnow]

Originally Posted by SOLAR SUPPORT

It only makes sense if an external regulator designed for the alternator is used when charging the Lifepo4 service battery bank, or if the Alternator is operated by externally controlling the operating temperature and charge voltage level using other methods.

If you have LA service batteries charged with the same alternator, plugging the fabricated alternator and new LFP starter battery into the old LA battery connectors and using them directly is also an option. You must use battery isolator.

Most standard alternator settings can be used to charge LFP. The primary issue is the over loading issue

[ranger58sb]

Originally Posted by ranger58sb

Why? What advantage(s) do you envision from LiFePO4 batteries in a starter situation?

Originally Posted by CaptainRivet

Use your house bank and just have the starter one as general backup.
LifePo4 has a very low resistance means the voltage drop/sag and current delivery is much better then any lead chemistry can supply.
Means the voltage and current at the starter is much higher, You will immediately realize that…starter spins effortless and that extends the lifespan of the starter significantly as the coils sees/get less amps and therefor less wear. The first that breaks on a starter is the magnetic switch, 2nd is burned through coils.
Same applies to the anchor windlass and even more as you operate it longer

Originally Posted by Ballsnall

Lot of effort just to go from 2 batteries to 1.
Charge profile, alternator protection etc.

And extra cost, too, I think?

Seems like maybe a technical improvement (if folks agree on that) -- where "good enough" and "relatively cheap" would be fine ???

Following because: our main batteries -- two pairs of 8Ds, 24VDC systems -- function as both starter (900 hp diesels) and house.

I've not ever had a starter go south. (Knock wood, of course.)

Nor a windlass motor. (Ditto.)

-Chris

[CaptainRivet]

Originally Posted by mqbenedict

I have a Universal 4 cylinder 36 hp. I had no trouble starting it by attaching one of these to the battery posts. Not a huge engine.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I keep it on board just for that purpose and was happy to have it as a last resort recently.

Good luck,
Mark

As handy as this starter pack is you have a fire hazard on board as these packs are LI-ion chemistry…the chemistry that catches fire and get thermal runaways.

[Fuss]

Originally Posted by CaptainRivet

Very bad ideas and combo.
1st Calb are excellent cells for storage use, not high C use.They can do 1C and 2C peak max.
2nd bypassing BMS while drawing high current is a noGo
3rd keeping SOC at 50% when drawing high C, your bank will be out of balance after 3 starts…and dead soon.
If then use a BMS that carries no current like Electrodacus. But your Calbs won‘t have a long life, I can promise you that.
At capacities around 100AH the LTO are the only chemistry that can really survive here.

Thanks again for the very good input.
Ok, then if capacities of around 100AH the LTO are the only chemistry then I have some comments....


This then means that all these drop in Lifepo4 Starter batteries do not work long term ...for example Dakota 60ah 1400cca Lifepo4 will also not have a long life.


The LTO Yinlong 40AH provide a peak discharge of 400AH says the spec, so 12 in 2p6s is 800AH max, which is a long way from 1400 as the Dakota above have for specs. So the LTO equivalent would be 24 in 4p6s costing around 1500€ and taking quite a bit of space.


So maybe I should look at some solutions that make my 12v start batteries similar to my 24v Lifepo4 280ah house batteries.


I could for example make a 12v 280ah start battery from the same cell type as the house bank. The advantage would be that they are not as stressed as 100AH cells (as they are 280AH) but then comes the next uncertainty...these 280AH cells have no peak discharge specs and for long life they are supposed to be charged and discharged at around 0.5c. So would they really be better than the calb solution that you say will not work or would they be better than the Winston 90AH solution that some people say should be ok?