Dwight Lindsey Posted August 12, 2023 Share Posted August 12, 2023 I have installed 3 200 amp Lithium Ion Phosphate house batteries and I'd like to charge them from the alternator. I've purchased a Renogy DC-DC charger, but I'm having trouble with the installation. Per the manual, I need to provide D+ voltage from the alternator. So far I haven't found the D+ output on the alternator. I cleaned the alternator enough to see that it's a Leece-Nevile, but that plate does not give it's model number. The alternator seems physically longer than the Leece Neville pictures I see online. Anyone know exactly which Leece Neville I have on my 05 Monaco Knight? Any hints on how to find the D+ terminal or wire? The space around the alternator is crowded with the starter motor and cables. I suspect the wire I need is on the top of the alternator, where I can't see it. I do wonder if there's another place I can get ignition voltage, maybe in the front run bay? At this point I'd rather run a wire from the front run bay than deal with the alternator. Any help would be appreciated. Dwight Link to comment Share on other sites More sharing options...
Mark B Posted August 12, 2023 Share Posted August 12, 2023 (edited) That D+ is just from the chassis battery side of the charging system. The DC to DC just regulates the amp draw from the alternator so it doesn’t overheat. I had one of those on my fifth wheel before I got my coach. Now I’m using a Victron DC to DC to charge my lithium batteries as I drive. You can connect it anywhere as long as the wire size is able to handle the amperage on either side of your charger. Also I believe the renogey has a charging trigger wire so that it only charges while the engine is running. The Victron is auto sensing. Edited August 12, 2023 by Mark B Link to comment Share on other sites More sharing options...
Rocketman3 Posted August 12, 2023 Share Posted August 12, 2023 I installed my Victron Dc-Dc charger in my rear run bay - I had both engine voltage and house voltage there. In big 4/0 cables - so it was a natural place for me to place it. Good Luck Link to comment Share on other sites More sharing options...
Ivylog Posted August 12, 2023 Share Posted August 12, 2023 I had my doubts about needing a dc-dc limiter. I’ve found my 08 Navigator’s alternator doesn’t overcharge or overheat charging my 800AH of Lithiums. Installed a remote temp sensor on the alternator and it stays the same as the terms of the top radiator hose. Link to comment Share on other sites More sharing options...
Dwight Lindsey Posted August 12, 2023 Author Share Posted August 12, 2023 What's wanted for D+ is essentially "ignition key on". Connecting this to the chassis battery would leave the charging circuit on at all times, which we don't want for fear of running down the chassis batteries. I would like a better understanding of my Leece Neville alternator but I'm already sure that the connection I need there is not easily accessible to me . . . so I'd like an ignition key on signal from the front run bay. I don't have a rear run bay . . . Dwight Link to comment Share on other sites More sharing options...
Dwight Lindsey Posted August 12, 2023 Author Share Posted August 12, 2023 OK, I think I'm on a path here. In my front run bay, on the inside of the main board box, the fuses are labeled: Here's what that looks like on the board: What I think happens is that when the ignition is on, the Ignition Relay (there are two of them) puts power to the fuses in the Ignition 1 and Ignition 2 fuse areas. Fuses 21, 23 and 24 are spares. Why there are fuses in those locations is puzzling. There are empty positions on the connector, that appear to confirm that those fuse positions are spares. I think what I need to do is get a wire into the connector, which I assume is a Molex Connector, at one of the empty sockets on the Molex, and fuse it correctly for the wire. Then run that wire back to the battery bay where I intend to install the Renogy DC-DC charger. Anyone know exactly that that MOLEX connector is? Comments? Dwight Dwight Link to comment Share on other sites More sharing options...
TomV48 Posted August 12, 2023 Share Posted August 12, 2023 2 hours ago, Dwight Lindsey said: What's wanted for D+ is essentially "ignition key on". Connecting this to the chassis battery would leave the charging circuit on at all times, which we don't want for fear of running down the chassis batteries. I would like a better understanding of my Leece Neville alternator but I'm already sure that the connection I need there is not easily accessible to me . . . so I'd like an ignition key on signal from the front run bay. I don't have a rear run bay . . . Dwight I have a full time 200 amp relay in my battery compartment that cross feeds chassis to house batteries. It activates from the boost button but also from an ignition 12 volt only from the IRD, ignition relay delay and comes on about 15 min after the engine starts, giving the chassis batteries a chance to recover. It probably would have been okay to charge my 600 amp lithium Bank directly from it but out of an abundance of caution I put in a 40 amp DC to DC Renogy. I took that IRD, 12 volt line and used it for the d+(if that's what it is called and I don't remember from when I installed it). I some times (often) get an error fault light. Renogy engineer had no solution so I have a breaker on both the chassis and coach batteries. Before we roll, I check. If there is an error/fault I shut both breakers off, turn em back on and all is well. Link to comment Share on other sites More sharing options...
PTTech Posted February 16 Share Posted February 16 On 8/12/2023 at 1:26 PM, Ivylog said: I had my doubts about needing a dc-dc limiter. I’ve found my 08 Navigator’s alternator doesn’t overcharge or overheat charging my 800AH of Lithiums. Installed a remote temp sensor on the alternator and it stays the same as the terms of the top radiator hose. What did you use for a remote temp sensor? Are you still running without the dc-dc charger? Link to comment Share on other sites More sharing options...
Ivylog Posted February 16 Share Posted February 16 2 hours ago, PTTech said: What did you use for a remote temp sensor? Are you still running without the dc-dc charger? Dual emote grill temp sensors… one on alternator and other on top radiator hose. Yes, still no DC-DC and I don’t disable the BigBoy. Link to comment Share on other sites More sharing options...
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