Lithium batteries and alternator protection.
The six 6 volt lead-acid house batteries in my class A DP have gone bad. I am looking to replace them with 6 Battleborn 100Ah 12v LiFePO batteries. Eventually I will be adding solar. I am not look...
Forum Discussion
Tom/Barb wrote:Our dc to dc charger is rated at 40a. Unless our lifepo4 cells are in the the last 5-10 min. of the charge cycle, it's always producing a constant, consistent 40a of charge current. We obtain 40a of charge current charging from 0 to near 100% SOC under all conditions. The converter in our camper, which is rated at 45a, operates just like our 40a dc to dc charger. Unless the lifepo4 is in the last 5-10 min. of the charge cycle, the converter is producing its rated 45a of charge current.BFL13 wrote:why would you mention Renogly when we are taking about Victron equipment?Tom/Barb wrote:We have had several threads about this. A recent one that might explain your set-up was that a "30A" DC-DC means output for a Renogy, but it could mean input for another brand.BFL13 wrote:the fallacy of your theory is Alternators don't always operate at peek power/voltage/potential
If the DC-DC is charging the house batts with 30 amps at 14.2v , that is 426 watts output..
The 30 Amp DCtoDC Charger is a limit, not a constant amperage.
In any case, input is higher in watts than output. If the input limit is 30A then at 13.2v that is 396 watts. Charger efficiency of 95% (being very generous) means output is 376 watts.
376/14.2 = 26.5 amps charging from the charger minus any wiring loss to the house batts for amps to the house batts
DC to DC chargers won't charge to 30 amps at all times, they will vary the amperage rate to 0 amps when the battery is fully charged.
I believe my system will never show 30 amps, because we never have seen 30 AMP charge rate in 2 years even the batteries are low .
we left Quartzite Az after 2 days on batteries and our batteries were topped up in 3 hours with out exceeding 20 amp charge rate.
I only know what I see on our system, other manufacturers may differ so don't confuse the issue.
You appear to have a 30a dc to dc charger that produces no more than 20a of charge current. One has to wonder what the 30a rating is for.
When a charging device has a given current rating, most would expect it to provide that rated current in the form of actual charge current. When it doesn't, then a clarification or explanation of the rating would certainly be helpful.
