Chuggs
RVF Supporter
- Joined
- Nov 3, 2019
- Messages
- 422
- RV Year
- 2016
- RV Make
- Newmar
- RV Model
- Ventana 4037
- RV Length
- 40’
- TOW/TOAD
- Jeep JKU
If you watch the dash, there is a yellow light which illuminates when you first turn the key. Diesels will have glow plugs or grid heaters. So, depending on temperature they may run a little or a lot. They put a nice draw in the batteries. Then you hit the starter...and that puts a huge drain in the batteries. So, the dash unit reads the battery voltage after start as LOW. They will recover, and when the alternator gets spinnin, you’ll probably see the dash voltage near 15v.
The 12.8v chassis reading, I am assuming on the digilevel display? That is pretty indicative of a chassis battery getting no charge...and has been resting. When you measured 13.6 at the chassis battery, it is telling you something different now. A charge is getting to them. If you have engine running...alternator —- if you don’t have engine running and the shore power is connected...you are sharing the Inverter Charger with the chassis thru the bi-directional relay. As a matter of fact...although not proof positive...but a high likelihood exists...if you look at the digilevel and both the House and Chassis are reading the identical voltage...mmmm the bi-directional relay has closed and both banks are joined and sharing a charge source.
The engine warmup and engine starter are probably why you are getting the swinging voltage for the chassis, engine lift pump for pressurizing diesel fuel to the rails. There is a good reason we have two group 31 starting batteries with 1000 Cold cranking Amps. The diesel sucks power for startup. Then a 240A alternator to replenish and keep things powered. There is a long wire run from the rear to the dash...the stuff in the back is going to hoard the voltage...but as long as your engine fires up without hesitation, and the chassis voltage recovers quickly after start up...you are doing okay!
The 12.8v chassis reading, I am assuming on the digilevel display? That is pretty indicative of a chassis battery getting no charge...and has been resting. When you measured 13.6 at the chassis battery, it is telling you something different now. A charge is getting to them. If you have engine running...alternator —- if you don’t have engine running and the shore power is connected...you are sharing the Inverter Charger with the chassis thru the bi-directional relay. As a matter of fact...although not proof positive...but a high likelihood exists...if you look at the digilevel and both the House and Chassis are reading the identical voltage...mmmm the bi-directional relay has closed and both banks are joined and sharing a charge source.
The engine warmup and engine starter are probably why you are getting the swinging voltage for the chassis, engine lift pump for pressurizing diesel fuel to the rails. There is a good reason we have two group 31 starting batteries with 1000 Cold cranking Amps. The diesel sucks power for startup. Then a 240A alternator to replenish and keep things powered. There is a long wire run from the rear to the dash...the stuff in the back is going to hoard the voltage...but as long as your engine fires up without hesitation, and the chassis voltage recovers quickly after start up...you are doing okay!
