Asking for advice here! I’m installing a Victron smart battery monitor and was checking out my battery situation - I have 2 AGM 6v batteries in series. I have a Freedom HF charger/inverter. Voltage reads always 13.4+. But turns out they were installed by PO 2012! Would you recommend keeping with the AGM or going with Lithium. And looks like Lithium comes in 12v so I could go one 12v 230ah but if I get the lithium, I couldn’t use the existing Freedom HF charger/inverter…. Can anyone recommend a battery charger for the above example! Suggestions welcome.
you can still use your Freedom HF, as long as you set it for flooded, see table from the manual:
I assume you are talking about LifePo4 batteries, which are less power dense but much safer than other lithium chemistries. Charging regime for these batteries is 14.2-14.6V bulk, with a float voltage of 13.6. I have a solar charger for a 200Ahr system and can set all voltages, but my previous setup had a charger set for flooded and it worked just fine. It will top out at about 90 odd percent at the slightly lower float voltage but that is no bad thing anyway.
I would recommend lithium, price has dropped considerably and they will last for 1000s of cycles whatever you do with them, i.e. even discharging to cutout, which I have done quite a few times on my small domestic solar system, I use to power my wood boiler. I also have lithium on my F21, solar charged again, with a flooded solar charger. I now have the comms unit to change out the voltages but have never bothered.
Perfect - I was t sure whether the flooded toggles settings would work with lithium. Sounds good to me and huge thanks!
Plan is to use the Freedom HF toggled to Flooded. Put in 2 12v 200ah lithium batteries in parallel to achieve 12v 400ah….let you know how it goes. And a Victron smart monitor.
….and all depends on the blasted footprint - I have limited room and the lithium battery is larger ( although lighter) than the AGM’s.
I replaced an 8D AGM with a 300AH (Redodo) Lithium and use the AGM setting to charge with. No problems for past two years. I expect I don’t get 100% of possible charge but it is much better than the AGM in terms of total usable power. I also added a temperature sensor on the alternator to cut charge current in half when alternator is too hot and it usually cuts in when motoring at low rpm in morning field or anchorages.
Question- I bought 2 12v 100 AH lithium batteries - will connect in parallel for 12v 200AH. Didn’t read the fine print of course - LiTime.com says do not use the batteries for start! We’ll, I use the one bank for start and house - they say the BMS will not handle a start on my yanmar 3gm30f motor - opinion here appreciated - I’d rather not the bother of adding a start battery and could we’ll go back to the AGM!
It depends on the specification of the battery and the requirement from the starter motor. Lead acid will generally provide high current and as the current increases the voltage will drop, limiting any damage to the battery. A CCA rating will tell you what it is capable of (cold cranking amps), usually 500+ for a diesel engine of any size. Lithium batteries on the other hand will pretty much deliver all their Amps at once and this will not do the battery any good. Cells are rated in S values, which is the current it can safely provide. A 1S battery cell of 10Ahrs will give 10amps of continuous current safely. So you need to look at the specs of your battery. It will either be an S value or a continuous current rating, as to avoid damage, the BMS will limit the current draw. Typically LifePo4 batteries have a 1S continuous current rating in their BMS, so 100A for one of your batteries or 200A if you start from the pair in parallel, in both cases probably not enough but check the specs.
With my 300 AH Li battery, 200A BMS I easily started my 3gm30F in 40 degree temperatures after sitting all winter. Cranking for about 20-30 seconds. I carry a “backup 12v AGM” just in case but have never needed to use it.
I appreciated all the inputs- good stuff . Well I bought 2 300 ah li batteries online- again not reading the fine print - company told me not to use the batteries for start- so I returned them! Bought 2 AGM same as my originals and installed them and all perfect….also added the victron battery monitor- I can see how many A and W each component adds to the system and how much my solar is adding - I like that - hoped my footprint was bigger for the lithium so I could add a start battery - down the road perhaps…. Thanks!