I hear what you are saying about the "help" part of the Surepower. Here are all the symptoms. If the rig sits for let's sayBlue~Go wrote: ↑March 27th, 2021, 1:56 pmOkay so it is draining your house batteries not the start battery? That's a different scenario than I was envisioning at first (good sleuthing, BobW!).Baja Bilo wrote: ↑March 27th, 2021, 1:32 pm It has had this problem since I purchased it. It's not a problem if I start it everyday or
have it plugged into shore power. I think the previous owner may have dealt with the
problem and never got it solved. When I was driving it home the coach low battery
alarm went off. It has 2 new coach batteries in it.
This is one of the main functions of a "separator" (aka combiner aka isolator). When either bank drops below a set voltage (for Blue Sea, 12.76), the connection opens so current can't flow between them. Some combiners are bi-directional, so charge power could go either way (1315 for example), while others are uni-directional so power can only go one way, which is typically from start bank to house bank (to charge while driving).Baja Bilo wrote: ↑March 27th, 2021, 1:32 pm Not knowing much about RV's I started poking around in the engine bay and found that the cable from the coach
batteries wasn't hooked up to the vehicle battery which meant the coach batteries weren't getting charged from the alternator. I'm wondering if the reason the cable wasn't hooked up was because the coach was draining the vehicle batteries.
Your mechanic may be a crack diagnostician, and totally on top of it. He'd be the exception in my experience. many "regular" mechanics would probably have no idea how an RV is wired (a boat electrician would have a better chance). So while he may be fantastic, if it were me I'd not assume that.
Can you just clarify one more time what the symptom(s) are?
1) Which battery is running down, start or house? Or both?
2) Are you saying this was happening even when the cable connecting start and house banks was not connected at all? If yes, then which bank was running down, start or house?
3) When does this happen? While driving only? While parked only? Both?
There is one other little "gotcha" on the Surepower, which is that many of them have "start helper." What this does is (sneakily, without telling you) if your start battery is too weak to start the vehicle, it combines your house bank with your start bank to help start the vehicle BUT NEVER TELLS YOU. So you could have a dead or weak start battery for eons and never know it. Since a diesel takes a lot of oomph to start, if this had happened and then you drove away, maybe a cascade starts and then your house bank trips the low voltage warning?
The above scenario may not apply, but if you want to explore this further it would be great if you could elaborate on the answers to the questions above.
BG
2 days between starting. The vehicle batteries don't have enough juice to crank the engine enough to start it. When I turn
on the key to cycle the glow plugs the vehicle volt meter will show maybe 11 volts, then there is a click and the voltage
meter jumps up and there is enough juice to start the vehicle. That indicates the start helper you mentioned. Other times
if it won't start I'll push the boost button and it will start. So my highly uneducated opinion is telling my that the vehicle
batteries are draining first and if the rig sits long enough the house batteries follow. If it sits for over 3 days there isn't
enough juice to start the rig. The house batteries were replaced last July, the vehicle battery on the frame rail was replaced
last June, and they installed a new battery in the engine compartment this week. All batteries have been charged to full and load
tested then left over night and by the next day the vehicle batteries have drained about 30%. This shop specializes in automotive
electrics but I hear your thoughts on the difference between automotive and RV electrics. The weather is getting nice here in Idaho
and I want to use the rig but don't want to get stuck somewhere. If I go to a camp spot with shore power I'll be fine, but I'd like to
go to some out of the way spots also. How about the generator, does the starter on it get power from the house or the vehicle
batteries? I don't claim to be an ace mechanic but I kind of know some of the basics. I was a floor covering installer for 30 years
then switched trades when I was almost 50 and worked as an electrician for 10 years. I would never claim to know everything about
electrical issues home or vehicle. They are both a never ending learning process. Thanks for your input, Steve.