DC to DC Chargers September 20, 2024, 10:47:52 am A question for the electrical wizards: I’ve been reading the Escapees Magazine series on RV Solar the last several months and the final article is regarding DC to DC chargers which allow charging the batteries while driving. My understanding is the newer LD’s, such as our 2017, charge the batteries while driving. Is that through use of a DC to DC charger or some other method?
Re: DC to DC Chargers Reply #1 – September 20, 2024, 02:38:01 pm Not sure what qualifies as a 'newer' LD, but there has been some mechanism for charging the house batteries using the engine alternator for years. There is a companion article with diagrams from the owners manual that describes what LD used in 2004 and before (not sure how much before), and what was used in 2005 + (not sure if it changed again in more recent years).The Lazy Daze Companion: Search results for isolatorIt would be a very primitive DC to DC charger, sending current through a one way passage from the engine alternator to the house batteries. I'm not sure how well the stock isolator/exciter works with Lithium batteries, but I'd like to know. My impression is that what is marketed now as DC to DC chargers are a bit more sophisticated. Rich
Re: DC to DC Chargers Reply #2 – September 20, 2024, 03:26:39 pm Greg,LD placed a magnetic solenoid under the engine coolant reservoir tank above the left wheel well. It connects the coach and engine batteries when the engine is running. The engine alternator charges the coach batteries then. It disconnects when the engine is off. For the coach batteries charger (the coach power converter and the solar panels) to charge the engine battery when the engine is off I added a Trik-L-Start (or Amp-L-Start if it is still made) that bypasses disconnected solenoid and sends charging/maintaining power to the engine battery. I attached the unit to the top of the wheel well by the solenoid. (See photo) The wiring connections were attached to the solenoid post.I made this modification to both my 2010 LD and 2021 LD and never had any problem with the system. LSL Products TRIK-L-START 5 Amp Starting Battery ChargerCall me if you have any questions,Mike C
Re: DC to DC Chargers Reply #3 – September 20, 2024, 04:17:44 pm Quote from: Mike Coachman - September 20, 2024, 03:26:39 pmI made this modification to both my 2010 LD and 2021 LD and never had any problem with the system. LSL Products TRIK-L-START 5 Amp Starting Battery ChargerNote the Trik-L-Start (and Amp-L-Start) devices are no longer available. The gentleman who designed and produced them passed away, I think a year or so ago. 1 Likes
Re: DC to DC Chargers Reply #4 – September 21, 2024, 09:59:46 am Thanks, Rich. I'll take a look at that Companion article. Michelle, thanks for the reminder that the company went out of business.Mike, it's all coming back to me. I actually installed the Trik-L-Start three years ago based on some conversations we had in this thread:Storing an LDPlease recall that I'm an electrical dummy and excuse my ignorance. So, if I did a lithium battery upgrade, would the Trik-L_Start need to be disconnected? Is there any value in adding a DC-DC charger?
Re: DC to DC Chargers Reply #5 – September 21, 2024, 11:29:38 am Quote from: HiLola - September 21, 2024, 09:59:46 amPlease recall that I'm an electrical dummy and excuse my ignorance. So, if I did a lithium battery upgrade, would the Trik-L_Start need to be disconnected? Is there any value in adding a DC-DC charger?Greg, since your rig uses a relay to connect the coach and chassis batteries together while driving, a dc-dc charger would be wise. Older rigs like ours use a diode isolator after the alternator, which seems to work well without additional equipment.Steve
Re: DC to DC Chargers Reply #6 – September 21, 2024, 12:08:17 pm Quote from: Steve - September 21, 2024, 11:29:38 amGreg, since your rig uses a relay to connect the coach and chassis batteries together while driving, a dc-dc charger would be wise. Older rigs like ours use a diode isolator after the alternator, which seems to work well without additional equipment.SteveWhen I converted to a 12V, 200AH Renogy LFP battery, I replaced my old inverter/charger with a Xantrex inverter/charger that could charge the coach battery at 80 amps. Since it was so quick and easy to charge with the generator, I decided the cost and complexity of a DC-DC charger to charge while driving had very limited value. I disconnected the solenoid coil to avoid any possibility of damage to the alternator from charging the lithium coach battery. That worked out well for a year, in part because I have 400w of solar power (it can also charge while driving Recently, at Larry's suggestion, I determined the alternator would not harm itself charging the coach battery, so I reconnected the solenoid. I now have chassis engine charging while driving with no additional cost or complexity. An advantage of using the chassis engine for charging is it can run and charge when the gas tank level is lower that 1/4 tank - not that I suggest you make routine use of that feature. 1 Likes
Re: DC to DC Chargers Reply #7 – September 21, 2024, 12:38:24 pm The Amp-L-Start does the inverse of the what was described for the DC-DC charger: it properly charges the lead-acid chassis starting battery from the house batteries. Use Search (under the tiny house icon) to find the thorough discussions of all of this.
Re: DC to DC Chargers Reply #8 – September 21, 2024, 01:23:14 pm Greg, you are OK to keep the Trik l Start in place as it suits your needs. Nothing else is needed.
Re: DC to DC Chargers Reply #9 – September 21, 2024, 02:24:58 pm Hi Greg; My Trik-L-Start didn't provide enough power to supply my power point (Ford dash) needs from the chassis battery, while parked. The Amp-L-Start needed a wire back from the dash area to prevent a feedback loop. My Amp-L-Start was also too large to fit in the space I had planned on near the LiF batteries. I removed the diode isolator also. RVTito (many online video's, knowledgeable, good presentation) had a $22 solar controller https://www.youtube.com/watch?v=exQSsTiclOo that he hooked up to his LiF batteries. The controller thought the Lithiums were a '24' solar panel, and would charge the 12v. lead acid battery at up to a 20 Amp rate, to a lead acid standard profile. Small waterproof, informative lights, (and inexpensive). It has been working well. Amazon again: Amazon.com : HUINE 20A 12V 24V Auto IP68 Waterproof PWM Solar Charge... (the 'output' to feed from the battery when the 'sun' isn't shining isn't used, since it isn't really being used that way). RonB As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.