#BATTERY TENDER AGM FREE#
Maintenance free flooded batteries are similar but prefer voltages upto 15 and amperages to taper to nearly zero. when a 100 amp hour capacity AGM battery accepts 0.5 amps or less, when held at 14.4 to 14.7v range at 77f battery temperature, only then can it be considered truly fully charged. The lower the average state of charge, and the higher the average battery temperature, the faster it degrades/ loses capacity and cranking amperage ability.Īn AGM can only be positively determined to be truly fully charged, when the amperage it accepts at a higher voltage, tapers to a prescribed level.
Anything less than this ideal is detrimental to the battery. Ideally the lead acid battery is always fully charged and kept cool. This collective ignorance drives up battery prices for all of us, and wastes resources.
#BATTERY TENDER AGM FULL#
Your vehicle's voltage regulator, wherever it is located, whether inside ECM or internal to alternator or on firewall( rare nowadays) is NOT going to hold the battery at this voltage for that long, even if you were to drive that long, so saying the best way to achieve a fully charged battery is a long drive, is incorrect, and helps contribute to batterycide, and collective ignorance of what a lead acid battery needs to remain healthy for as long as possible.ĭetermining a true full charge is easy with an Ammeter or a hydrometer or both, but no one ever does it, instead assuming that a battery which can still start an engine is fully charged or nearly so. The lesser the voltage( electrical pressure) they are held at the longer it takes to fully charge them, and less than healthy batteries might never be able to reach full charge at voltages less than the mid 14 range. Less than healthy batteries take longer, and in some cases significantly longer before they reach full charge. It also assumes the battery is still relatively healthy.
Getting an 80% charged battery to 100% charged, takes no LESS than 3.5 hours, and this assumes the battery is held in the mid 14 volt range for that 3.5 hours. The closer the battery is to full charge, the slower it charges. Lesser sun angles will be worse.ĪLL lead acid batteries take a lot of time to complete a true full charge. Immediately after, At the same exact angle behind the windshield, I measured 43 watts and this tapered to 37 watts as the panel heated up 15 minutes later.Īny solar panel charger/maintainer behind the windshield needs to reduce the potential expected wattage by ~50% over its claimed rating, and this is at noon at 32 north. On top of the windshield near noon I measured 87 watts into my depleted battery through a MPPT solar controller. I have a 100 watt 'flexible' Sunpower solar panel which can fit behind my windshield, without any shadows from the wipers.