โJun-22-2021 11:13 AM
โJun-27-2021 09:37 AM
StirCrazy wrote:You mentioned in a previous post you wanted to keep your voltage drop down to less than 1%. 1% for our install (23 ft.) would have required 4/0 cable. We're experiencing a ~2.5% voltage drop using 2 gauge cable (~10% overall conversion loss w/40a Renogy). For our install, 2 gauge provided us max. bang for the buck (cost, installation hassle, voltage drop, etc). If our install had required a ~30 ft. cable run, like many 5r/TT installs require, we'd probably bumped up to a 1 gauge cable to keep our conversion loss at <=10%.
thats what I wanted to see. do you think there would be any benifit of going larger than 2ga or do you think at that point its not worth the extra money?
Steve
โJun-27-2021 08:11 AM
โJun-27-2021 07:24 AM
otrfun wrote:
Took these current/voltage readings right after we installed a 40a Renogy dc to dc charger in our truck camper (truck has a 220a alternator). Used ~23 ft. of 2 gauge cable to fabricate the positive run from the TV battery to the Renogy located in our truck camper (via several 175a Anderson-type connectors). Used approx. 5 ft of 2 gauge for the negative run (truck frame just below the truck bed to the Renogy in the truck camper). Remaining negative run (from the truck's battery to the front of the truck bed) was via the truck's frame and OEM negative cabling. All readings are approx.
1. 14.1v 43.5a measured where the 2 gauge cable terminated at the TV battery terminal (alternator online)
2. 13.8v 42.2a at the Renogy's input terminal
3. 40a at Renogy output terminal (current remained steady at approx. 40a while charging LifePo4 battery from 15% SOC to ~97% SOC)
4. 39.8a at LifePo4 battery terminal (~10 ft run of 2/0 cable from the Renogy to the LifePo4 battery; voltage drop <.1v)
You can drop these current readings by 50% if you want to get a rough idea of how a 20a Renogy would have performed (installed on our TC and truck). This would be based on using one cable size larger than what Renogy recommends for the 20a Renogy for our install. Renogy recommended 4 gauge for our 40a Renogy install; we used 2 gauge.
โJun-27-2021 07:20 AM
BFL13 wrote:
You can install yours and see what you get. The owner's manual says input amps will be 50% more than output amps at max amps, so expect 60 when yours is doing 40. It does say the unit will "perform better" with less voltage drop on the input side. It does not say that better performance will mean fewer amps.
BFL13 wrote:
There is also heat. The unit's fan comes on. Some watts are involved there.
BFL13 wrote:
A lesson learned was to by-pass the 7-pin connectors for both pos and neg. Those connectors work for the signal lights but sure have high R for the 12v charging wire pins. If we still had the 5er, I would look at that even with no Renogy involved, where 7-pin charging is so lame.
โJun-27-2021 07:03 AM
pianotuna wrote:Bypassing the dc to dc charger when you need a really quick, fast charge would be nice option to have.
. . .
Now if someone would connect bypassing the Renogy....and compare that to Ren in, Ren out.
โJun-27-2021 06:39 AM
โJun-27-2021 06:05 AM
โJun-26-2021 08:47 AM
โJun-26-2021 07:56 AM
โJun-26-2021 06:48 AM
โJun-26-2021 05:59 AM
BFL13 wrote:
Input voltage was 10.42, now it is 11.28v. No change in output no way to know the draw (assumed still 30 amps)
โJun-25-2021 02:58 PM
CA Traveler wrote:
It is for sure that larer wire reduces voltage loss and reduces power for a given amps. The resulting power for the output (with device losses) is available at the output with different amps and voltage.
โJun-25-2021 02:28 PM
โJun-25-2021 02:14 PM
โJun-25-2021 01:54 PM