![]() Fire up the engine, and amp flow from the factory solenoid’s previous maximum of thirty amps now reads fifty-something. DC amps from the house battery to inverter/floodlight was upper forties. House battery drained to about 12.2V, not connected to start battery, engine not running. The next experiment was with a 2000 watt inverter connected to the house battery, with a 120vac, 500 watt floodlight load. ![]() I can see why sometimes links get replaced by fuses. Try to feed a too-hungry battery or accessory load, possibly poof, and you’re hoping to make it somewhere on battery power alone. When they heat up, they become resistors. ![]() Go dig around the web and find out what current those fuse links can pass for how long before blowing. Let’s hear it for the 14.8v, 130 amp alternator and the amp flow limiting wiring!ĪLL of that 130 amp alternator’s possible output flows through two #12 gauge grayish fusible link wires, also in the diagram below. When using the original factory supplied small yellow wire feed through the solenoid, the initial charge current is slightly less than thirty amps, and drops to about sixteen amps in short order as battery voltage/internal resistance rises and possibly the yellow wire heats up. My 100 amp hour AGM will accept amps in the mid-upper forties connected to a 14.8vdc source with heavy cables when down about 12.2vdc, but that charge current goes down fairly rapidly to the thirties. Whatever system is used, device amp ratings or voltages mean little if the amps aren’t flowing. That importance of measuring amps is mentioned more in older threads, but not so much recently in the DC to DC charging/solenoid/isolator debates. Without knowing actual DC charging amps, everything else is speculation. My biggest mistake was not measuring actual current flow to the house battery when maximum charging was needed as step #1. That 130 amp alternator suddenly seemed much smaller. It seems the Ford designers deliberately undersized the yellow wire for resistance to limit current flow and the fuse made sure it didn’t rise above 60 amps maximum. 6VDC measured from battery to battery was actually due to resistance from the fuse box source to the solenoid on that small yellow wire instead of across the contacts. DC voltage measured directly across the solenoid’s contacts at maximum charging read. I “won” a 1994 EVTM (wiring) manual and discovered the yellow wire on the solenoid was fed from a hot all the time 60 amp fuse “T” in the engine fuse panel. The other side has the red #4 headed to the house battery. I finally noticed the smallish (no larger than #10) yellow wire on the main contact right side. The continuous duty solenoid is hidden underneath the start battery’s box, accessible by removing the headlamp and looking through a fist-sized hole behind it. That made it seem the solenoid’s contacts were iffy, causing a resistance, reduced amp flow and power loss. Happy, lucky me until noticing that when the house battery needed full charge, the voltage measured from start to house battery positive posts was. I installed a toggle switch to turn off the solenoid when desired. I later found out why the batteries aren’t connected in START. Solenoid energized except in OFF and START. Batteries up front on both sides, connected with a #4 copper wire. ![]() The voltage reduces magically to about 14.0 when both batteries are charged and everything’s heated up. I purchased a 1994 Econoline with a factory installed simple solenoid-connected system that seemed to be the fifty dollar special, and a 130 amp alternator that maxed out at 14.8vdc. The values below are from over three years ago, old man memory, might not jive mathematically, and are meant for system operation rather than specifics. This is not for the highly technically skilled posters who’ve advanced way beyond my needs and experience, and surely needs editing. I’m not a Legitimate ExPo Guy, and basically interested in keeping a 12v fridge running with a simple system. Using the alternator for charging an auxiliary battery with a solenoid/isolator OR a DC-DC booster can really tax the alternator. Installing the 50 dollar special does not guarantee high current/amps house battery charging from the alternator even if it has the required high voltage. You don’t know how many charging amps are flowing unless you measure it. If you have the higher voltage, you have amps flowing or you don’t. If you don’t, either boost the alternator’s charging voltage somehow or use other charging systems with the required higher voltage. Either you have a charging system with a high enough voltage or you don’t. The 50 dollar dual-battery thread is golden, and great for simple auxiliary battery charging, but It pays to know what you have to begin with.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |