Anyone Use LTO for a Starting Battery?

[Dedou]

The voltage regulator on the outboard has a chance of malfunctioning but you can use a 9a DC to DC to charge the LTO's also. Once the LTO is charge up from the alternator it should be 14.4v and no more will flow or voltage rise if the regulator is working properly.

Do you mean ALT->DCDC->LTO ? I thought the charger only works in one direction. What about starting current peak, can dcdc handle that?

 

[jah]

Do you mean ALT->DCDC->LTO ? I thought the charger only works in one direction. What about starting current peak, can dcdc handle that?

Don't overcomplicate things, use the DC-DC to charge the lifepo4, and connect the LTO directly to the alternator, it only gets a peak for a few seconds and the own alternator is limiting its output to the max in its limits.
When the lifepo4 will be full, still the alternator will have the LTO as a buffer, when the LTO will reach the alternator output voltage, it will provide only the current the engine requires

 

[Dedou]

Don't overcomplicate things, use the DC-DC to charge the lifepo4, and connect the LTO directly to the alternator, it only gets a peak for a few seconds and the own alternator is limiting its output to the max in its limits.
When the lifepo4 will be full, still the alternator will have the LTO as a buffer, when the LTO will reach the alternator output voltage, it will provide only the current the engine requires

Like my original plan?:

Hi, I am planning to install the next configuration.

Boat Outboard (18A charge) -> 35Ah 6s LTO-Battery to start -> 9A DC-DC Charger - > 160Ah 4s Lifepo4 Battery.

LTO only works for startup, LFP for electronics. The question is, what happens when both batteries are full? DC-DC protects the outboard alternator by limiting the charging current, when the LFP is full and BMS shuts down, LTO protects the alternator from load dump, but what happens then? when both batteries are full? The current drops to 0A, so the voltage goes up? The LTO max voltage is 16.8v i.e. it does handle it but does the outboard voltage regulator or something else break down?

 

[jah]

Like my original plan?:

I apologize, I was confused because the replies

Don't worry about the rest of the elements, they are designed to work with the voltage the alternator provides to the lead-acid battery that is the same you will have when the LTO will be full and the BMS open.

I have done what you are planning in a Ford Transit, and it works ok, I have reviewed it even from the own vehicle scan, and the alternator tries to supply the voltage it is designed for, initially 15,2v, which means lots of amps, my alternator is 220A, setting that voltage means about 150A.
In a few seconds, it lows the voltage to 13,7v and then only provides the amps to compensate the load from the engine.

 

[bgflyguy]

I wanted to give a 5 or 6? Month update.

I have been running without a balancer in place and hit around 40mv difference between cells. Since I'm not going above 14.5v that's probably somewhat substantial? Anyway, I haven't had any issues, so I plugged in the balancers and we are back on track. I'll try to check back in after a few more months running this way.

 

[bgflyguy]