too much charger?

[mlydon]

I accidentally fried the Freedom 10 installed on my boat trying to run a shopvac....

So I spotted a CF member selling a freedom 25 near me and snapped it up, thinking a straightforward swapout was in order.

However, it seems that you shouldn't charge flooded batteries over 15-20% of capacity, and the '25 puts out 130 amps, vs my 400ah bank.

Have I shafted myself? Do I need to go out and get a 50-60amp charger? There doesn't seem to be any way to limit or dial-down the charge rate on the freedom 25.

I figure I either need to get a 60 amp charger or buy some firefly batteries which can take an incredible rate of charge, BUT they're never available and cost a lot of money, plus require odd charge settings which a xantrex freedom probably can't do.

Am I overthinking things? Are their any tricks to a Freedom 25 I'm unaware of? My usual experience is that the current going into batteries, very quickly drops below what the alternator or charge CAN do. On the other hand, I don't want to blow myself up.....

TIA,

Matt

[motion30]

the charger will only put out with the batteries can accept. the larger charger will be fine

[john61ct]

With lead batteries their high resistance self-regulates current accepted, as long as voltage is well capped.

In fact most quality AGM makers recommend at least .2C rate, Odyssey even specs .4C (160A!) as the **minimum** charge rate for longevity.

With all sealed batteries you need to ensure Absorb charge doesn't go on too long, but most sources drop to Float too early rather than late.

FLA are pretty indestructible just keep water up.

When going to LFP, all this changes, then you need to be aware when current limiting at the source is important.

[noelex 77]

As Moton30 and John have indicated the larger charger will be fine.

[a64pilot]

You can’t have too big a charger, in my opinion a bigger charger is good for several reasons.
1. It’s my belief that many electronics if not run at their max output, run cooler and will last longer.
2. Don’t forget about house loads, if you have a 10 amp house load, that comes off the top of the charger, reducing charge capacity by 10 amps or whatever the house load is.
3. Bigger can reduce time to charge by a little, not as much as you might think because banks limit what they can accept, but it will charge a little quicker, time dependent on depth of discharge.