lawrosa wrote:
BFL good read from 2008....lol
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/22180733/srt/pa/pging/1/page/15.cfm
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/22180733/srt/pa/pging/1/page/15.cfmIn the above blurb from WFCO they are confusing Boost and Absorption this time. The "preset" drop out for deemed "full" is actually when it drops out of the absorption stage of the battery.
Most chargers do that around the 97% SOC point and let the battery complete the recharge during the subsequent Float. It is not a WFCO fault. Absorption can go to infinity unless you cut it off somewhere.
What WFCO says is that their 14.4 Boost will run for 4 hours or less if it hits the preset. During that four hours, the battery does Bulk and Absorption. If the absorption gets the amps tapered down to the preset, the converter stops its Boost at 14.4 and drops to 13.6.
The problem with the WFCO is getting it to trigger its Boost at 14.4 with that 13.2v trigger. It is all about that initial spike in voltage once the charger gets on the battery. If the spike stays below 13.2v, it will go into Boost.
That means the battery and wiring from it to the WFCO must have low R, which means the battery must be low R and the wiring be low R. The spike also relates to the size of the battery bank in AH (bigger means lower R and vv) wrt to the initial charging amps. Higher percentage of amps to AH means a higher spike.
So to keep that spike from going over 13.2 you should not hit the smaller bank with a bigger amp WFCO. You also need short fat wiring and no loose connections to keep the R down that the WFCO "sees"
That is why time2roll advises to use a 35 amp WFCO on a small battery bank instead of your 55 amper, because when the small bank is down to 50% and so needs a recharge, the 35 amper might not spike the batts above 13.2, whereas the 55 amper will. Especially if the wiring is long and thin. Note--that "might" work--it all depends on the total set up.
I don't blame the WFCO as such, but the way it works is not suitable for most RVs where you just can't get that spike to be under the magic 13.2 trigger.
