On board DC to DC charging Lithiums

[disorderly]

I see that now I know when I looked into it a couple of years back they didn't

So do you know how much charge would go into 2 x 125 amp LiFePO$ batteries via a trollbridge (assume a 40amp alternator) ?

Chris

From what Trollbridge told me.....25amps per hour divided by 2 for the first 30 minutes then 18 amps divided by 2 thereafter (in my case with 36v it was divide by 3)......hardly worth it unless you spend hours trolling between bottom bashing..

[Lovey80]

From what Trollbridge told me.....25amps per hour divided by 2 for the first 30 minutes then 18 amps divided by 2 thereafter (in my case with 36v it was divide by 3)......hardly worth it unless you spend hours trolling between bottom bashing..

Are you sure that wasn't Sterling? Those are the figures they state as the sterling down rates after a while due to temp.

I saw Yandina reply to a few threads on THT. They claimed up to 100amps but on 70amp (output) alternators you could expect 60 amps across the Trollbridge to the batteries. So there is some loss there converting to 24/36v as you would expect.

[NAGG]

Are you sure that wasn't Sterling? Those are the figures they state as the sterling down rates after a while due to temp.

I saw Yandina reply to a few threads on THT. They claimed up to 100amps but on 70amp (output) alternators you could expect 60 amps across the Trollbridge to the batteries. So there is some loss there converting to 24/36v as you would expect.

So based on a big outboard (225hp +) ... 70amp alternator you are talking 30amps / hr ( twin batteries for a 24 vlt leccy)
With my Suzuki with a 40 amp alternator - I can expect half that (there abouts) ...... say 15amps / battery ....... which would be next to useless for me .

Chris

[NAGG]

Maybe this could be an option from Victron - Orion-Tr12/12-30(360W) Apparently they can be hooked up in parallel to increase output

Maybe someone with a good electrical background can comment

Chris

[Lovey80]

So based on a big outboard (225hp +) ... 70amp alternator you are talking 30amps / hr ( twin batteries for a 24 vlt leccy)
With my Suzuki with a 40 amp alternator - I can expect half that (there abouts) ...... say 15amps / battery ....... which would be next to useless for me .

Chris

What Suzuki are you running?

Maybe this could be an option from Victron - Orion-Tr12/12-30(360W) Apparently they can be hooked up in parallel to increase output

Maybe someone with a good electrical background can comment

This wouldn't help your situation though would it?

[disorderly]

Are you sure that wasn't Sterling? Those are the figures they state as the sterling down rates after a while due to temp.

I saw Yandina reply to a few threads on THT. They claimed up to 100amps but on 70amp (output) alternators you could expect 60 amps across the Trollbridge to the batteries. So there is some loss there converting to 24/36v as you would expect.

It was 18 months ago, that I had some conversations with a Trollbridge guy, so i may be wrong...

But I thought is was basically half or a third of the original amperage into each battery if you had 24 or 36v...

Whatever it was it was more then enough to convince me that it was not worth it for my my types of usage ...

[Greg P]

Not running Litiums - still on AGM but I have been running the Sterling Pro Charge B (1224) for a few years without too many issue but am just about to actually change out to a Minn Kota DC to DC charger. Something to consider with the Sterling is the fact you are charging 2 x 12v batteries collectively as 24V which is not normally a problem unless you have a troublesome cell which then impacts your overall charge level. Would be the same for Litium but assume with the inbuilt BMS you would get an idea if a cell was on the fritz. I am going with the Minn Kota MK-2DC (2 bank) for the ability to charge both batteries individually as 12v rather than both @ 24v.

[NAGG]

What Suzuki are you running?



This wouldn't help your situation though would it?[/COLOR]

140 DF

I'm not sure if the Victron would help ....... but if you ran 2 in parallel .... it may - from my understanding that would be 30amps / battery

Chris

[Lovey80]

140 DF

I'm not sure if the Victron would help ....... but if you ran 2 in parallel .... it may - from my understanding that would be 30amps / battery

Chris

if your DF140 is producing 40amps and has say 30Amps available for charging, adding an extra charger won’t help. 30amps is the most that will go into the bank no matter what way you send it there.

[fishtragic]

Thanks for the input everyone, sorry I haven't replied, been jumping through some medical hoops. Lovey, it's a 225xca Yammy, 70A output and you are correct in that I am trying to put some DC/DC charge back into the 3 x 12v lithiums after crank batt. top up while on extended trips. I don't really expect to keep up with MK use, more to extend the time I get from spot locking. Anyway I have the charger now so I'll fit it and give it a go. From what I can gather from the tech. specs it is as simple as plug and play. Hope so, I don't speak electricity.

[Lovey80]

I hope you report back on how it all goes.