And apparently Grand Design never got the memo.
This is related to a couple of existing posts, but thought I'd add my experience with our 2021 imagine XLS 22mle. We've had it a couple of years and I noticed that the stock charging inverter does a really slow job of charging of the batteries. I have 2x 6v golf cart batts in series . It's not a huge problem when plugged in, but is a pain when off grid and relying on generator for charging. Looking through some of the historical posts here I've noticed that many people with battery issues are recommended to just go to LiFePo4 batteries for faster charging among other benefits. I'm not against the advice, but if you think you're going to fix a stock setup with a simple battery swap, think again.
I can't speak for any other models or brands, but my trailer is set up with 8 awg wiring for the battery main wiring. I was amazed when I saw this (for lack of a better word that doesn't involve a 4 letter word). I estimated that the main power cable has about a 35' run when it heads back into no man's land to the power switch, and arrives at the charger inverter toward the back of the trailer. So out and back, that's approximately a 70' run.
The company installs a 55A charger and expects it to charge the battery. Using a wire size calculator (I like the Blue Sea circuit wizard online, as I'm a boat guy and have done a bit of marine electrical work), if you plug in the numbers, the recommended wire size for that distance and 55 amps would be around 2/0 wiring. The voltage drop using 8 awg will be close to 25%!
So I did a little test. I have a battery monitor shunt installed at my batteries and ran them down below 75% state of charge so I could see just what the charger sent to the batteries. At the start of charging it only put out 16 A. Within several minutes the charge dropped to around 8 A and stayed there for the duration.
So what happened? My theory. First, there's no way it could ever send 55A to the batteries with that small gauge wire. Second, due to the resistance, when charging, the charger is seeing a much higher voltage than the battery and it goes into a variable current mode very early. In essence, it behaves no better than a 10A trickle charger.
The fix? Either replace all the wiring (huge job), move the charger inverter to a location near the battery (another big job) or just install a second good quality smart charger right near the battery (my solution). I plan on putting a Victron 30 A charger in the pass through and plugging it into the existing 120 v outlet there. Currently waiting to see if there's any kind of black Fri. deal coming up, but not holding my breath.
Most owners just plug their trailers in all the time at camgrounds, so they'll likely never notice this charging problem. Lead acid batteries should be charged up to an absorption voltage and held in that phase for a while when charging. It affects longevity of the battery when they aren't. This will never happen with the stock setup, at least on my trailer, as I've never seen battery voltage over about 13.8 v. Hope this bit of info may be helpful to someone else.
This is related to a couple of existing posts, but thought I'd add my experience with our 2021 imagine XLS 22mle. We've had it a couple of years and I noticed that the stock charging inverter does a really slow job of charging of the batteries. I have 2x 6v golf cart batts in series . It's not a huge problem when plugged in, but is a pain when off grid and relying on generator for charging. Looking through some of the historical posts here I've noticed that many people with battery issues are recommended to just go to LiFePo4 batteries for faster charging among other benefits. I'm not against the advice, but if you think you're going to fix a stock setup with a simple battery swap, think again.
I can't speak for any other models or brands, but my trailer is set up with 8 awg wiring for the battery main wiring. I was amazed when I saw this (for lack of a better word that doesn't involve a 4 letter word). I estimated that the main power cable has about a 35' run when it heads back into no man's land to the power switch, and arrives at the charger inverter toward the back of the trailer. So out and back, that's approximately a 70' run.
The company installs a 55A charger and expects it to charge the battery. Using a wire size calculator (I like the Blue Sea circuit wizard online, as I'm a boat guy and have done a bit of marine electrical work), if you plug in the numbers, the recommended wire size for that distance and 55 amps would be around 2/0 wiring. The voltage drop using 8 awg will be close to 25%!
So I did a little test. I have a battery monitor shunt installed at my batteries and ran them down below 75% state of charge so I could see just what the charger sent to the batteries. At the start of charging it only put out 16 A. Within several minutes the charge dropped to around 8 A and stayed there for the duration.
So what happened? My theory. First, there's no way it could ever send 55A to the batteries with that small gauge wire. Second, due to the resistance, when charging, the charger is seeing a much higher voltage than the battery and it goes into a variable current mode very early. In essence, it behaves no better than a 10A trickle charger.
The fix? Either replace all the wiring (huge job), move the charger inverter to a location near the battery (another big job) or just install a second good quality smart charger right near the battery (my solution). I plan on putting a Victron 30 A charger in the pass through and plugging it into the existing 120 v outlet there. Currently waiting to see if there's any kind of black Fri. deal coming up, but not holding my breath.
Most owners just plug their trailers in all the time at camgrounds, so they'll likely never notice this charging problem. Lead acid batteries should be charged up to an absorption voltage and held in that phase for a while when charging. It affects longevity of the battery when they aren't. This will never happen with the stock setup, at least on my trailer, as I've never seen battery voltage over about 13.8 v. Hope this bit of info may be helpful to someone else.
Last edited: