Redarc 40 amp DC to DC Charger issue

StirCrazy wrote:
ya I was thinking that with the dc to dc charger you don't need an isolater as it basicly is one, if its off there is no passthrough if its on then you get charging. the reason I want to be able to manualy turn it off is more to take strain off the altanator when it isn't nessasary. so I would be treating my dc to dc charger as an emergency power sourse only. so if it has been cloudy and I am getting a lousy charge from the panels I can turn it on while I am driving to help out and so on..

Steve

What size alternator? What size dc to dc charger do you use, or plan to use? It should be safe to leave a 20a dc to dc charger on full-time in most smaller vehicles. Most of the Renogys have a half-power mode. You could use a 40a unit in 20a mode for now. If you upgrade to a vehicle with a larger alternator in the future, you could switch back to 40a. Or, you might find your current vehicle will handle 40a just fine. Bottom line, it gives you some choice, flexibility.

We don't use our 40a Renogy for backup/emergency power. It gets extremely hard use during the summer when we're on the road. Use our 200ah lifepo4 to power our truck camper a/c when we take breaks. It only takes our a/c about 5-10 min to make the TC noticeable cooler---plus, no generator setup/startup or rumble. Once back on the road the dc to dc charger goes to work. Usually stop for a break after 1.5 - 2.0 hours of driving, which is about the time the dc to dc charger needs to top-off the lifepo4 again. On any given summer travel day the Renogy gets a *lot* of use---as much as 6 hours at max current. The lifepo4 works hard, too---after 9 mo. already approaching 40 cycles.