Lead Acid to LiFePo4 in a Vehicle

[DezMan]

I’m trying to get familiar with the solar config before I spend too much money on an off-grid system.

For starters, I have a 2002 Bombardier Sea Doo Boat. I want to convert the two existing batteries, 1) to start the motor and 2) the accessory battery, to LiFePo4.

Is this all I need?
https://www.victronenergy.com/media...tml#UUID-3e81b633-d489-3af2-8b7d-54c1624783b5

And do I connect my Boat's ignition switch to the remote input?

Eventually I want to connect a solar panel that will keep the battery maintained while it’s parked on land.

 

[sunshine_eggo]

I’m trying to get familiar with the solar config before I spend too much money on an off-grid system.

For starters, I have a 2002 Bombardier Sea Doo Boat. I want to convert the two existing batteries, 1) to start the motor and 2) the accessory battery, to LiFePo4.

Is this all I need?
https://www.victronenergy.com/media...tml#UUID-3e81b633-d489-3af2-8b7d-54c1624783b5

And do I connect my Boat's ignition switch to the remote input?

Eventually I want to connect a solar panel that will keep the battery maintained while it’s parked on land.

The biggest issue with using LFP for starter batteries is that the surge current of the starter motor is too high, and it will cause the BMS to enter either short-circuit or over-current protection mode.

You are using a battery that can handle the starter motor current?

 

[mikefitz]

2002 Bombardier Sea Doo Boat

The available DC power generated be the engine generator may not be enough to drive the DC to DC charger.
More information is needed, engine power and maximum DC amps developed, engine model.
Existing batteries, starter and auxiliary, what Ah? How is the existing accessory battery charged?
From info I have, the starter battery is 18Ah, a motorcycle battery, is this correct?

 

[DezMan]

The biggest issue with using LFP for starter batteries is that the surge current of the starter motor is too high, and it will cause the BMS to enter either short-circuit or over-current protection mode.

You are using a battery that can handle the starter motor current?

That’s a great question. I have not purchased either battery yet. I’m glad I asked as I didn’t even consider this fact. Thank you!

This is from my manual:
Recommended: Exide R-24-130, 12 V, 25 A•h (130 minutes reserve) or R-24-160 (160 minutes) or equivalent.
Battery posts: On top. Round taper type.
Battery maximum allowed size: 285 mm (11-1/4 in) long x 190 mm (7-1/2 in) wide x 238 mm (9-3/8 in) high.

 

[DezMan]

The available DC power generated be the engine generator may not be enough to drive the DC to DC charger.
More information is needed, engine power and maximum DC amps developed, engine model.
Existing batteries, starter and auxiliary, what Ah? How is the existing accessory battery charged?
From info I have, the starter battery is 18Ah, a motorcycle battery, is this correct?

No.

This is from my manual:
Recommended: Exide R-24-130, 12 V, 25 A•h (130 minutes reserve) or R-24-160 (160 minutes) or equivalent.
Battery posts: On top. Round taper type.
Battery maximum allowed size: 285 mm (11-1/4 in) long x 190 mm (7-1/2 in) wide x 238 mm (9-3/8 in) high.

That’s a great question. I have not purchased either battery yet. I’m glad I asked as I didn’t even consider this fact. Thank you!

This is from my manual:
Recommended: Exide R-24-130, 12 V, 25 A•h (130 minutes reserve) or R-24-160 (160 minutes) or equivalent.
Battery posts: On top. Round taper type.
Battery maximum allowed size: 285 mm (11-1/4 in) long x 190 mm (7-1/2 in) wide x 238 mm (9-3/8 in) high.

 

[Rocketman]

If you just want to convert the accessories battery to Lithium - then yes the Victron DC to Dc charger will do a good job - as long as your alternator is large enough to drive it. (30amps or 50amps - depending on the model selected - note the 30 amp one run very warm/hot - I have heard the 50a one does not run hot). You can keep Lead for the starter and Lithium for the accessories- that is basically what I have for my MotorHome.

Now if you want to replace the starter battery with a lithium - there are more considerations (probably more than I list).

What is the exact voltage of the charging current from the alternator at idle and at power?
Is it a good voltage match for the battery or too high?

Is the alternator a smart alternator - or will it keep high voltage to the battery the whole time it is running?

If the BMS trips while running (from cells getting out of balance and one runs high), will that blow your diodes in the alternator? Or the engine computer? Do you need an alternator protection device?

Will the battery BMS have enough amps to start the motor? - Locked Rotor Amps to start turning.

Proceed carefully and find out the reasons why not many vehicles have lithium starting batteries - if you can overcome or minimize the reasons why it’s not usually done - go for it -

And report back!

 

[mikefitz]

alternator is large enough to drive it.

It may not be an standard alternator. The exact model of boat is not known, 'sea doo' covers a range from jet ski to small speed boat. All use a water jet propulsion system with small engines, some with a 300 watt magneto generator,

 

[DezMan]

If you just want to convert the accessories battery to Lithium - then yes the Victron DC to Dc charger will do a good job - as long as your alternator is large enough to drive it. (30amps or 50amps - depending on the model selected - note the 30 amp one run very warm/hot - I have heard the 50a one does not run hot). You can keep Lead for the starter and Lithium for the accessories- that is basically what I have for my MotorHome.

Now if you want to replace the starter battery with a lithium - there are more considerations (probably more than I list).

What is the exact voltage of the charging current from the alternator at idle and at power?
Is it a good voltage match for the battery or too high?

Is the alternator a smart alternator - or will it keep high voltage to the battery the whole time it is running?

If the BMS trips while running (from cells getting out of balance and one runs high), will that blow your diodes in the alternator? Or the engine computer? Do you need an alternator protection device?

Will the battery BMS have enough amps to start the motor? - Locked Rotor Amps to start turning.

Proceed carefully and find out the reasons why not many vehicles have lithium starting batteries - if you can overcome or minimize the reasons why it’s not usually done - go for it -

And report back!

You’re Rocketman?!
Any relation to “Little Rocketman”?!

That’s for the tips. I think I’m going to stay away from the starter battery, at least for now.

But am I not up against the same challenge with the accessory battery’s compatibility with the alternator?

 

[Rocketman]

No relation…

As long as there is a dc-dc charger between the two - and the alternator is large enough to drive the dc-dc charger - then you should be good.