Which B2B?

If I had 200Ah of Lithium my feelings are to charge through 2 X 30 Amp Tr-Smarts. This would limit charge current to around 60 A max, with the option to turn one off if needed (not sure why I'd need to!).

The thought of having the alternator current limit due to temperature sends shivers through my spine, call me old fashioned. The only thing I've built that would current limit on temperature was a heater circuit to stabilise oscillators in radios!
 
Like you said there is the is the option of adding 2 b2bAs lithium can take
wildebus said:
what do you mean? 30a can =60a ?
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lithium charges 2x as quick as lead acid, so on this assumption, a 30A charger thatt takes 1 hour from a to b for lead acid would take half hour on lithium
 
landoboguy said:
Like you said there is the is the option of adding 2 b2bAs lithium can take

lithium charges 2x as quick as lead acid, so on this assumption, a 30A charger thatt takes 1 hour from a to b for lead acid would take half hour on lithium
Click to expand...
nope. That is not how it works.
Just because a Lithium battery might be able to take twice as much current in say as a Lead Battery of the same capacity doesnt mean it can double the current from a charger! you dont get 60A from a 30A charger because you have lithium.

if you have 30A charger, it can put upto 30A into the battery. If the Lead Acid Battery bank can accept 30A, it gets 30A, just the same as a Lithium Battery would get also get 30A.
IF you had a 30A charger and your lead acid battery bank could only handle a 15A charge, in THAT case you might get twice the charge in - but only because the 30A charger is wasted on that lead acid bank and you have bought the wrong charger.
If I changed my Batteries from Lead Carbon to Lithium , I wouldn't get twice as much charge into the battery from my 60A B2B, it would be exactly* the same (in the main Bulk charging mode**).


*Now a different thing on charging difference ... A lithium battery can convert more of the input current into a charge as it is more efficient, so in THAT respect, more of the 30A from a 30A charger gets converted into a useful charge on Lithium compared to Lead Acid (but the difference doesn;t add up to double the efficiency. generally about 10% difference)
** Also, when the battery gets at the top end of the charge, a Lead Acid battery will take in less and less current to complete the charge whereas a Lithium will use it all until full - so in THAT respect, the charger utilization is better.
 
Thanks Wildebus, Ive queried this with the battery manufacturer and reply is below? . Note Its based on time I assume, so a 30a charger putting 30 a into lead takes one hour, the same 30a into a lithium, half an hour. But I see what you are saying that it doesnt equate to exactly that, there is some trade off.

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The B2B should be based on the alternator size more than the battery.

I would recommend starting with one of these. You can always add another later if you find you really need more.

Lithium charges 2x as quick as lead acid. So it’s the equivalent of charging lead acid at 60 amps time

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landoboguy said:
Thanks Wildebus, Ive queried this with the battery manufacturer and reply is below? . Note Its based on time I assume, so a 30a charger putting 30 a into lead takes one hour, the same 30a into a lithium, half an hour. But I see what you are saying that it doesnt equate to exactly that, there is some trade off.

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The B2B should be based on the alternator size more than the battery.

I would recommend starting with one of these. You can always add another later if you find you really need more.

Lithium charges 2x as quick as lead acid. So it’s the equivalent of charging lead acid at 60 amps time

-------------------------
Click to expand...
Well, all I can say is that advice from the battery manufacturer is rather confusing (and makes little sense to me how it is worded)
 
Yes, Im in a bit of a quandry, Ive emailed back and as xsilvergs says, adding another is possible if required.
My daily usage can be quite different depending on where i am and what job Im doing, but with the solar and the victron b2b should keep me going for a while to get some real world tests.
thanks for replies.
 
Didn't realise you can double up on B2B's, will bear that in mind. May be obvious but you do need to run the engine or travel with a B2B, not always what you want as a full timer. In that respect a second B2B may not be best for me but will see.
 
landoboguy said:
Thanks Wildebus, Ive queried this with the battery manufacturer and reply is below? . Note Its based on time I assume, so a 30a charger putting 30 a into lead takes one hour, the same 30a into a lithium, half an hour. But I see what you are saying that it doesnt equate to exactly that, there is some trade off.

-----------------------
The B2B should be based on the alternator size more than the battery.

I would recommend starting with one of these. You can always add another later if you find you really need more.

Lithium charges 2x as quick as lead acid. So it’s the equivalent of charging lead acid at 60 amps time

-------------------------
Click to expand...
I want lithium based Beer, because every time I order a half pint I'm going to get given a Pint. :)
 
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