This subject has come up before with @Drover explaining what he could not do, and how he got around the problem. At a recent caravan park stay, I came across the same problem but this time I had the time to document exactly what does happen. It will be of interest to anyone who has a BMpro 35 fitted in their van.
Firstly, van in question was a 2018 Jayco Penguin owned by a young lady who had the van (pre-owned) for approximately 8 months. Van bought with no battery or removed by previous owner. New owner wanted to go off grid occasionally, so battery needed. Went to local auto store for info and purchase. First mistake!! In response to her request for a suitable heavy duty battery, the auto store was happy to sell her something without knowing anything about how/where it was to be used. Got sold a 103ah heavy duty wet cell (the flooded type) with removable filling caps. Would probably start a truck but not the type you want bubbling and charging away releasing lots of hydrogen under your bed with a gas stove nearby. She was very concerned when I explained what she had, and was going to change to an AGM, but that was the least of this person's lack of knowledge.
She had a couple of trips on and off grid before Christmas and on the last trip travelled for over 4 hours before putting van into her storage shed. The 4 hour drive would surely recharge the battery from her modern SUV. Second mistake. As set out on another post, this is far from correct as modern alternators do not charge aux batteries properly, if anything at all!!
The van was not connected to power for over 14 weeks!! On the the evening of departure to Poona the power was connected "to get the fridge cooling and recharge the battery" before driving approx 4 hours to park. Third mistake! First night at park on powered site connected to grid, 12 volt lighting lasted only 10 minutes before going off. Lady used emergency switching on BMpro to finish up for the night. Second night, and no 12 volt power available even though connected to grid for more than 36 hours!! Sought my help as I have an earlier2013 model.
So at 7.45am, arrived with multi- meter and clamp meter. Oh oh! A BMpro 35. @Drover's post started to ring bellls of warning!! Tested battery - just 10.30 volts open circuit!! And the LVD had been activated, so no 12 volt loads until 12.8 volts had been reached by external battery charging. Warned owner that recovering a flooded battery from that low may not be possible. All 12 volt switches OFF and battery switch OFF, disconnected neg lead and hooked up charger in situ. Just happened to have my 12 volt 15A 7 stage "smart" charger with me to charge up battery on Son in Law's kayak. Took more than 30 minutes to complete de-sulphation cycle and move on to "soft start". Charging voltage struggling to get over 11.5 volts. An hour later, came back from fishing (no fish) and checked progress. Now into "bulk" charge stage and inputting 13.3 amps, battery electrolyte starting to bubble furiously. After lunch, another check, still in "bulk" charge but voltage up to 12.65 and current now down to 8.8 amps. Worth a try to see if BMpro will carry load and start its own charging, but no go!! @Drover was right.!!
Left it until nearly dark before checking again at 5.30 pm. Lady owner now really worried whether she would have 12 volt lighting that evening. Readings gave hope. Charging voltage now up to 14.35 volts and current down to 4.3 amps and in "absorption" stage. Time for test... turned off charger, voltage dropped to 13.65 volts, connected battery cable, turned battery switch to ON, .....and waited.....turned on a couple of 12 volt lights....... eureka!! They came on, voltage dropped approx .3 volt and held. Now the real test......... connected van to grid (and BMpro ) ...........and bingo, voltage slowly rose confirming that unit was capable of charging battery again. Lady advised to use as much 12 volt power as she wanted that night and I would check again in the morning.
Next morning, battery voltage steady on 12.65 volts and appeared to be slowly rising as day went on. A 6 pack of great cider and a box of quality chocolates gratefully accepted. Lady stayed another night with all lights burning before departing hopefully better educated and much, much wiser about battery management systems especially BMpro 35.
WARNING: If you let the van battery drop below 10.5 volts or lower, and the Low Voltage Disconnect is activated, you are in a world of trouble as the BMpro 35 will not charge the battery. And until battery voltage exceeds 12.8 volts, you are without ANY 12 volt power from the battery. Only option is to charge battery with battery charger , which will be a real problem if off grid even if you just happen to have a charger. You then have to wait until voltage is higher than 12.8 volts before re-connection to battery for 12 volt loads can occur. Could be a BIG problem!!! Obvious need to have a volt meter connected across terminals (and monitor reading) at all times unless you have peripherals that go with the unit.
For those of us who have the superseded Setec Series II or III, we may be behind in technology, but we are ahead in practicality. The Setec does not charge as high, (only 10A verses 15A) but the 0.7 amp trickle current is ALWAYS available. It may take all night to get sufficient voltage into a really low battery to get Setec to start charging at 10 amps and to re-connect battery to loads (only have to get to approx 11.5 volts if careful), but so much better IMHO to have some way to increase voltage albeit very slowly. Even solar could do this and you would not be in the dark until re-connected.
Sometimes I wonder if the BMpro 35 is progress!!! Thanks for reading this "fresh from the field" experience. @Drover , you started this!!!
Firstly, van in question was a 2018 Jayco Penguin owned by a young lady who had the van (pre-owned) for approximately 8 months. Van bought with no battery or removed by previous owner. New owner wanted to go off grid occasionally, so battery needed. Went to local auto store for info and purchase. First mistake!! In response to her request for a suitable heavy duty battery, the auto store was happy to sell her something without knowing anything about how/where it was to be used. Got sold a 103ah heavy duty wet cell (the flooded type) with removable filling caps. Would probably start a truck but not the type you want bubbling and charging away releasing lots of hydrogen under your bed with a gas stove nearby. She was very concerned when I explained what she had, and was going to change to an AGM, but that was the least of this person's lack of knowledge.
She had a couple of trips on and off grid before Christmas and on the last trip travelled for over 4 hours before putting van into her storage shed. The 4 hour drive would surely recharge the battery from her modern SUV. Second mistake. As set out on another post, this is far from correct as modern alternators do not charge aux batteries properly, if anything at all!!
The van was not connected to power for over 14 weeks!! On the the evening of departure to Poona the power was connected "to get the fridge cooling and recharge the battery" before driving approx 4 hours to park. Third mistake! First night at park on powered site connected to grid, 12 volt lighting lasted only 10 minutes before going off. Lady used emergency switching on BMpro to finish up for the night. Second night, and no 12 volt power available even though connected to grid for more than 36 hours!! Sought my help as I have an earlier2013 model.
So at 7.45am, arrived with multi- meter and clamp meter. Oh oh! A BMpro 35. @Drover's post started to ring bellls of warning!! Tested battery - just 10.30 volts open circuit!! And the LVD had been activated, so no 12 volt loads until 12.8 volts had been reached by external battery charging. Warned owner that recovering a flooded battery from that low may not be possible. All 12 volt switches OFF and battery switch OFF, disconnected neg lead and hooked up charger in situ. Just happened to have my 12 volt 15A 7 stage "smart" charger with me to charge up battery on Son in Law's kayak. Took more than 30 minutes to complete de-sulphation cycle and move on to "soft start". Charging voltage struggling to get over 11.5 volts. An hour later, came back from fishing (no fish) and checked progress. Now into "bulk" charge stage and inputting 13.3 amps, battery electrolyte starting to bubble furiously. After lunch, another check, still in "bulk" charge but voltage up to 12.65 and current now down to 8.8 amps. Worth a try to see if BMpro will carry load and start its own charging, but no go!! @Drover was right.!!
Left it until nearly dark before checking again at 5.30 pm. Lady owner now really worried whether she would have 12 volt lighting that evening. Readings gave hope. Charging voltage now up to 14.35 volts and current down to 4.3 amps and in "absorption" stage. Time for test... turned off charger, voltage dropped to 13.65 volts, connected battery cable, turned battery switch to ON, .....and waited.....turned on a couple of 12 volt lights....... eureka!! They came on, voltage dropped approx .3 volt and held. Now the real test......... connected van to grid (and BMpro ) ...........and bingo, voltage slowly rose confirming that unit was capable of charging battery again. Lady advised to use as much 12 volt power as she wanted that night and I would check again in the morning.
Next morning, battery voltage steady on 12.65 volts and appeared to be slowly rising as day went on. A 6 pack of great cider and a box of quality chocolates gratefully accepted. Lady stayed another night with all lights burning before departing hopefully better educated and much, much wiser about battery management systems especially BMpro 35.
WARNING: If you let the van battery drop below 10.5 volts or lower, and the Low Voltage Disconnect is activated, you are in a world of trouble as the BMpro 35 will not charge the battery. And until battery voltage exceeds 12.8 volts, you are without ANY 12 volt power from the battery. Only option is to charge battery with battery charger , which will be a real problem if off grid even if you just happen to have a charger. You then have to wait until voltage is higher than 12.8 volts before re-connection to battery for 12 volt loads can occur. Could be a BIG problem!!! Obvious need to have a volt meter connected across terminals (and monitor reading) at all times unless you have peripherals that go with the unit.
For those of us who have the superseded Setec Series II or III, we may be behind in technology, but we are ahead in practicality. The Setec does not charge as high, (only 10A verses 15A) but the 0.7 amp trickle current is ALWAYS available. It may take all night to get sufficient voltage into a really low battery to get Setec to start charging at 10 amps and to re-connect battery to loads (only have to get to approx 11.5 volts if careful), but so much better IMHO to have some way to increase voltage albeit very slowly. Even solar could do this and you would not be in the dark until re-connected.
Sometimes I wonder if the BMpro 35 is progress!!! Thanks for reading this "fresh from the field" experience. @Drover , you started this!!!
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