Silicon Dioxide Batteries

[tpbrady]

Murray,

I use a Sterling Power Alternator to Battery Charger that works well for the AGM's. I thought they were going dead 3 years ago due to abuse and a strange wiring arrangement by the PO. I since fixed the wiring and added the Sterling product which I use with a stock Delco Alternator. The AGM's are now 7 years old and seem to be doing well. I am looking at new batteries in a couple of years so am watching the LFP's and then you brought up the Silicon batteries. What I can't get my arms around is charging LFPs from the alternator. Most of the batteries I have looked at specify a max continuous charge of 100A or so and a preferred charge of 50A. I am not quite sure how to charge a bank of 2 8D equivalent 200AH LFPs from a 200A stock alternator.

Tom

 

[MurrayM]

Murray,

I use a Sterling Power Alternator to Battery Charger that works well for the AGM's. I thought they were going dead 3 years ago due to abuse and a strange wiring arrangement by the PO. I since fixed the wiring and added the Sterling product which I use with a stock Delco Alternator. The AGM's are now 7 years old and seem to be doing well. I am looking at new batteries in a couple of years so am watching the LFP's and then you brought up the Silicon batteries. What I can't get my arms around is charging LFPs from the alternator. Most of the batteries I have looked at specify a max continuous charge of 100A or so and a preferred charge of 50A. I am not quite sure how to charge a bank of 2 8D equivalent 200AH LFPs from a 200A stock alternator.

Tom

Hi Tom,

Does the Sterling Alt to Batt charger work as advertised...does it really charge batteries faster? Also, do you notice it shutting down if/when the alternator gets too hot?

So many ways to skin a cat!

 

[tpbrady]

Murray

The Sterling works the way they say. I haven’t had any cases of the alt shutting down. The highest charge current I have seen is around 130 amps when SOC was showing 85% on 900 AH bank.

Tom

 

[bglad]

Battery with built-in BMS

Without considering costs this outfit makes their batteries with the BMS built-in. Essentially plug and play. I came across a user last year who had three of the 8D size format and he had no complaints. Only $10,000 or so for the three...

https://relionbattery.com/

LiFePo4 batteries have a legitimate claim when it comes to cost vs longevity, but how much (in a ballpark percentage of the whole) does a battery management system add to the cost?

I have an internally regulated alternator, so even changing to AGM would get expensive after a new alternator and some sort of charge controller.

 

[twistedtree]

Murray,

I use a Sterling Power Alternator to Battery Charger that works well for the AGM's. I thought they were going dead 3 years ago due to abuse and a strange wiring arrangement by the PO. I since fixed the wiring and added the Sterling product which I use with a stock Delco Alternator. The AGM's are now 7 years old and seem to be doing well. I am looking at new batteries in a couple of years so am watching the LFP's and then you brought up the Silicon batteries. What I can't get my arms around is charging LFPs from the alternator. Most of the batteries I have looked at specify a max continuous charge of 100A or so and a preferred charge of 50A. I am not quite sure how to charge a bank of 2 8D equivalent 200AH LFPs from a 200A stock alternator.

Tom

The charge rate is per-battery, so multiply times the number of batteries in parallel. Typical charge rate guidance is .25C to .5C, aka 1/4 to 1/2 of the Ah capacity (C) of the bank. So a 400Ah bank, which would be two 200Ah batteries in parallel, could be charged at up to 200A (.5C)

 

[Delfin]

Murray,

I use a Sterling Power Alternator to Battery Charger that works well for the AGM's. I thought they were going dead 3 years ago due to abuse and a strange wiring arrangement by the PO. I since fixed the wiring and added the Sterling product which I use with a stock Delco Alternator. The AGM's are now 7 years old and seem to be doing well. I am looking at new batteries in a couple of years so am watching the LFP's and then you brought up the Silicon batteries. What I can't get my arms around is charging LFPs from the alternator. Most of the batteries I have looked at specify a max continuous charge of 100A or so and a preferred charge of 50A. I am not quite sure how to charge a bank of 2 8D equivalent 200AH LFPs from a 200A stock alternator.

Tom

If you have a two bank setup - starter/house - charging LFPs is not very complicated. And, even if you have a single bank and are happy to, and have the ability to float the LFPs at 13.3 - 13.4 volts for a 12 v bank, you can do fine.

I made no changes to my setup after installing them a couple of years ago other than I added 3 x Sterling chargers so I could charge at .3 C when on the hook and running the genset, and changing settings on the Balmar regulator. Not sure, but I assume the Sterling charger will allow changes to bulk voltages, absorption duration, etc. With 400 Ah (I think that is what you are saying you would have), your 200 amp alternator should be detuned to around 150 amps or so, and that would put you in what I think is the sweet spot for my LFPs of around .3C.

 

[DDW]

"Recharge immediately after use" can`t be taken literally, if it was the battery would have to constantly under charge.

This is the recommendation for most lead acid chemistries, as they sulfate quickly if left for any period of time in a partial state of charge. The fact that they print this on the case suggests the same concern for SiO2.

The weak point of LFP at this time is the care and feeding needed: they want to be stored in a partial state of charge, and that is not so easily done. With LA batteries in intermittent use (like most boats) you just return to the marina, plug them in, a proper charger brings them to a float state while you walk away. LFP on the other hand, should be run down to 40 - 60% before leaving them. Then when you return next month you are starting the weekend with partially discharged batteries. Currently, that makes LFP a better fit for live aboard on the hook use where they have many advantages, vs. weekend use stored in a marina, or marina live aboard.

The carbon foam batteries seem to have nearly the same life kept in float or partial state of charge - that's why people are paying more for them. No one seems to know on SiO2.