Capt Jon
Observer
Diplostrat taught some electrical classes at Expo East, and I learned enough to understand (sorta) why my system wasn't working, but didn't get far enough in the time allowed to get very far into solutions . . . . It's progress to know what you don't know, right?
I was using a Nat. Luna power pack with an Optima Group 31 Yellow top in Dubai to run a National Luna fridge (Weekender 50). On almost every trip, the fridge would be screeching its low battery alarm 7-8 hours after I shut off the truck at night. (late model 70 series LC). (Fridge was packed cold and chilled overnight in the house before leaving, ambient temps usually in the 70-90F range at night. Fridge was usually set to -1* C, no travel cover, but plenty of ventilation. I worry about the sufficency of the insulation no the fridge because the outside was always very cold to the touch). My goal is to run the same fridge on short camping trips in the US, not that unusual I would think. Hopefully at a little lower ambient temps.
After listening to Fred's excellent presentation, my theory is that two things may have been hurting me:
(1) I simply never got the battery topped up due to the combination of low Toyota-specific charging voltages and the fact that my 30-minute commute was simply never long enough for the battery to spend enough time in the absorption phase of the charge cycle. So I was essentially never getting the battery over 80% charged. (optima G31 = 75AH, 80% of that is 60AH, and 50% of that is 30AH. But, even in Dubai, I am having a hard time believing the fridge was pulling 30AH in 7-8 hours).
and (2) I think the battery alarm on the fridge is much more conservative than I am. While I appreciate a conservative approach, I am willing to deplete the battery a little further than the Engineers at NL. I don't mind replacing the battery at 3 years instead of 5-6 if it gets me what I need.
The question becomes what to do about it?
I am back in Atlanta, and in another Landcruiser. I don't know, but expect that my 1990 FJ62 is not going to charge any better than my 2015 76-series did. My commute is actually shorter than it was in Dubai, so I am not likely to get much improvement there.
Things I am considering:
Dual batteries - Blue Sea ACR to keep them separate when not being charged. The NL box will still be around for horse shows, but won't live in the truck. So I can plug it into a charger between trips. A higher-capacity G31 battery - something in the 100AH range.
Pigtail - Fred mentioned a plug in pigtail that tricks the Toyota voltage regulator into giving a little higher charging voltage.
Solar?????? - I want something to top up the batteries during the week, and don't think I will be on the road enough, but then again maybe I will? A 30-minute commute is five hours of charging a week, plus whatever good I do on the drive back from camping trips. Shouldn't the charging be cumulative?
I am not stationary enough to need solar that keep up with a fridge for days at a time. I just want to get the battery topped up during the week so I am good for the next trip. Am I going to have to install a permanent panel on the truck? Am I better off just plugging it in at night? How is the rest of the world dealing with this?
If I am at a slightly higher voltage, will that be sufficient to keep an aux battery healthy and up to full charge?
Battery Charger at the house - Is my 40-year old Sears battery charger going to take care of topping up the batteries, or have I entered a world where that's suddenly not good enough?
I would love some advice/comments from the good folks here, but admit that I may not be able to tell the difference between the experts and the internet commandos.
I was using a Nat. Luna power pack with an Optima Group 31 Yellow top in Dubai to run a National Luna fridge (Weekender 50). On almost every trip, the fridge would be screeching its low battery alarm 7-8 hours after I shut off the truck at night. (late model 70 series LC). (Fridge was packed cold and chilled overnight in the house before leaving, ambient temps usually in the 70-90F range at night. Fridge was usually set to -1* C, no travel cover, but plenty of ventilation. I worry about the sufficency of the insulation no the fridge because the outside was always very cold to the touch). My goal is to run the same fridge on short camping trips in the US, not that unusual I would think. Hopefully at a little lower ambient temps.
After listening to Fred's excellent presentation, my theory is that two things may have been hurting me:
(1) I simply never got the battery topped up due to the combination of low Toyota-specific charging voltages and the fact that my 30-minute commute was simply never long enough for the battery to spend enough time in the absorption phase of the charge cycle. So I was essentially never getting the battery over 80% charged. (optima G31 = 75AH, 80% of that is 60AH, and 50% of that is 30AH. But, even in Dubai, I am having a hard time believing the fridge was pulling 30AH in 7-8 hours).
and (2) I think the battery alarm on the fridge is much more conservative than I am. While I appreciate a conservative approach, I am willing to deplete the battery a little further than the Engineers at NL. I don't mind replacing the battery at 3 years instead of 5-6 if it gets me what I need.
The question becomes what to do about it?
I am back in Atlanta, and in another Landcruiser. I don't know, but expect that my 1990 FJ62 is not going to charge any better than my 2015 76-series did. My commute is actually shorter than it was in Dubai, so I am not likely to get much improvement there.
Things I am considering:
Dual batteries - Blue Sea ACR to keep them separate when not being charged. The NL box will still be around for horse shows, but won't live in the truck. So I can plug it into a charger between trips. A higher-capacity G31 battery - something in the 100AH range.
Pigtail - Fred mentioned a plug in pigtail that tricks the Toyota voltage regulator into giving a little higher charging voltage.
Solar?????? - I want something to top up the batteries during the week, and don't think I will be on the road enough, but then again maybe I will? A 30-minute commute is five hours of charging a week, plus whatever good I do on the drive back from camping trips. Shouldn't the charging be cumulative?
I am not stationary enough to need solar that keep up with a fridge for days at a time. I just want to get the battery topped up during the week so I am good for the next trip. Am I going to have to install a permanent panel on the truck? Am I better off just plugging it in at night? How is the rest of the world dealing with this?
If I am at a slightly higher voltage, will that be sufficient to keep an aux battery healthy and up to full charge?
Battery Charger at the house - Is my 40-year old Sears battery charger going to take care of topping up the batteries, or have I entered a world where that's suddenly not good enough?
I would love some advice/comments from the good folks here, but admit that I may not be able to tell the difference between the experts and the internet commandos.