Bongo Fury

Hi

I have an leisure battery fitted but after driving back for 100 miles I notice this morning the battery is almost flat with just the fridge being on all night. How can I test if it is receiving charge?

As I understand the system that once the car battery is fully chaged, which it is, the charge is diverted to the leisure battery.

Also if you are on site with an electric hook up would this normally top up the leisure battery?

Derek

Hollis wrote:Hi

I have an leisure battery fitted but after driving back for 100 miles I notice this morning the battery is almost flat with just the fridge being on all night. How can I test if it is receiving charge?

Stick a multi-meter across the terminals, set to measure Volts-DC. The voltage should be 11.5-12.5 ish with the engine off. This should rise to 13.8-14.5 with the engine running.

Hollis wrote:Also if you are on site with an electric hook up would this normally top up the leisure battery?

Simple answer is "it depends". If you have a PMS panel, then they can be set to charge from hook-up, it it's a model with a built-in charger. My self-build has a 12v DC PSU/Charger which charges the L/B and runs the 12v systems when on hook up. Not all systems are equal though. Do you have a wiring diagram, or model details of what you have installed?

Yes that's what you would expect: Charging from alternator whilst on the move and charging from EHU via some control unit when plugged in.
If the battery isn't charging when on the move then things to check are the;
Two fuses close to each battery that link the batteries via the split charge relay, these tend to be in-line fuse holders,
Split Charge relay itself - there are two types of relay Voltage sensitive which operate when the voltage on the S/B rises above a set point, and switched via ignition switch.

Checking to see if there is charge charging going on is best done by measuring the voltage across the L/B, at rest it should be about 12.6 volts when fully charged, or down to around 11 volts if discharged. When the Split Charge Relay operates then you should see the voltage rise to the same as across the S/B when the engine is running that will be about 13.6-14.4 volts.

Hi

Ploblem solved. Tested as you said and no change with the engine running. Checked the fuses and one was blown. Replaced this fuse and now it is reading higher with the engine running. Many thanks.

Derek

If one fuse blew then its worth replacing BOTH of them as they will have both been very hot and one just went before the other (usually by milliseconds) so you may find that the other one will blow at a lower current next time!