2004 Chevy 190P, 3 110AH AGM's, 300W Solar. Replaced the isolator with a Blue Sea 7622 AGR(Automatic Charging Relay), upgraded the main 12v feeder line between the engine compartment and the house electronics with 2/0 cable. Ammeters on the alternator and on the feeder cable from chassies to house.
From memory (NOT trustworthy in the least), on our last trip the chasies seemed to use 40A or so. The alternator put out a max of 100A, but that was only for seconds before it ramped down. The alternator seemed to settle down around 60A. I can get better numbers if it would help.
I am considering upgrading my stock alternator. The changes I made still don't allow the batteries to charge, say, from 92% to 98% over a two hour drive. I'm not ready for a second alternator - which winds up being expensive by the time you are done
Solar usually takes care of normal traveling - 1 or 3 nights camping then a few hour drive. If we don't have enough sun to keep the batteries topped up, I'd like them to charge close to 100% on the drive. We rarely stay where there is AC power.
Can anyone reccomend a specific alternator? Something that will put out more juice and is able to run cooler?
Thanks! Steve
We can recommend alternators for sure, but the alternator is not the issue in the situation you list. AGMs take a long time to do the last 20% of charging to full, as much as 5-6 hours or more, so what you are seeing is totally normal. AGMs can be charged at about .4C, or about 130 amps, without them getting to hot, even though they may want to accept more than that (so good to limit amps to them). The problem is that they will only accept charge that fast up to about 70-80% full, and after that the acceptance drops very quickly to barely anything by the time they are full. Lifelines, for instance, want .5%C to be at full which would be only 1.6 amps at end of charge.
We all have been down this road, and you are in a perfect position to handle it, I think. You have 300 watts of solar, so you just let the solar finish the charge once it get down to a level the solar can cover. Many of us do that, including us. We have 440ah of AGM in an 07 190P with 300 watts solar.
You have enough battery to accept 130 amps for quite a while, and have adequate wiring in place, so you could probably benefit from a larger alternator if you often have to recover from deep discharges below 50% SOC. Your Chevy is a 2004, so you have options the same as we did, as you have an alternator that has an internal regulator and is not chassis computer controlled. You can put in a bigger alternator in the stock place, but the 130 amps plus running the van is going to be quite a bit for even a high output unit, any you would need to limit the amps to the coach. You can put in a separate standalone alternator with a Balmar regulator on it and use the Balmar to turn it down to 50% so a 270 amp alternator would put out about 135 to the coach only and leave the stock alternator to run the chassis. You could also replace both alternators with high output ones and run them parallel, you would need to match them to each other and control both off a Balmar at 50% turndown. Using two stock 145 Chevy alternators in parallel and needing a 130 amps plus 25-50 to run the van would also work out pretty close to what you need. Depending on how you do it, having the Blue Sea relay with the manual override switch to shut off might be a good idea.
We have probably the only, or one of the only, big parallel systems with 530 amps of total alternator power. We have a now unavailable Ample Power regulator that lets me set two levels of turndown off a switch and control absorption or float stage from a switch. I am currently set at 120 and 180 amps on our 440 amp hours. We used to have it at max, so 180 and 280 amps, but never used the 280 amps so make it lower and easier on all the parts. I think I have used the 180 amps once or twice only. We usually use 50 or so Ah per day, so even 120 amps gives us a day's power in a trip to a trialhead or dump station.
If you do decide to use the solar to top off your AGMs, you will need to make sure you can keep it in absorption voltage to do it. We have a Blue Sky controller that allows us to set it up have long absorption times and not go to float until it hits the very low final amps to the batteries, so when the engine goes off it is still in absorption and carries on. Most controllers will go to float by voltage when the engine is running and not do very well topping off.
There are several threads on our system on this forum from 5 or so years ago when I put it together. For the way we use the van, it has been exactly what we need, and without a generator.
