95D190P Engine Battery Charging

[blackbourn3704]

Does the engine battery get charged from shore power? Mine does not (not now anyway)

[Rlum]

Usually not. The isolator separates the chassis battery from house battery. House battery is charged from the converter designed for them. You can design a system where the chassis battery can be charged from shore power. I believe such devices/ systems can be purchased over the counter?

[booster]

Originally Posted by Rlum

Usually not. The isolator separates the chassis battery from house battery. House battery is charged from the converter designed for them. You can design a system where the chassis battery can be charged from shore power. I believe such devices/ systems can be purchased over the counter?

If you want to charge in both directions and still separate when not charging, you just need to replace the diode isolator with a relay style automatic charge relay/separator. Lots of folks have done that upgrade.

[Rlum]

Originally Posted by booster

If you want to charge in both directions and still separate when not charging, you just need to replace the diode isolator with a relay style automatic charge relay/separator. Lots of folks have done that upgrade.

I have a Sure Power 1314-200 Uni Directional Battery Separator- 12 volt. What relay style automatic charge relay/separator would work best? Chassis battery is AGM and house battery is lithium.

Thanks

[booster]

Originally Posted by Rlum

I have a Sure Power 1314-200 Uni Directional Battery Separator- 12 volt. What relay style automatic charge relay/separator would work best? Chassis battery is AGM and house battery is lithium.

Thanks

With mixed batteries like that, I don't really know if you should do bi-directional relay or not because of the voltage of the lithium battery will hold the separator closed and drain the lithium charging the starting battery, possibly at very high amperage.


Most with a mixed system like that would have a B to B charger in the circuit to isolate the lithium and some of the B to B chargers do have an out put to charge the starting battery, I think.


Just tying them together without the diodes probably wouldn't be a good choice unless you add a B to B and then you lose the bi-directionality anyway. AFAIK, you could just remove the isolator if you put in a B to B charger.

[Rlum]

Originally Posted by booster

With mixed batteries like that, I don't really know if you should do bi-directional relay or not because of the voltage of the lithium battery will hold the separator closed and drain the lithium charging the starting battery, possibly at very high amperage.


Most with a mixed system like that would have a B to B charger in the circuit to isolate the lithium and some of the B to B chargers do have an out put to charge the starting battery, I think.


Just tying them together without the diodes probably wouldn't be a good choice unless you add a B to B and then you lose the bi-directionality anyway. AFAIK, you could just remove the isolator if you put in a B to B charger.

Thanks for the information. I have a solar controller and dedicated 100watt panel to trickle charge the chassis battery. I was looking a way to reduce to a single charging source?

[booster]

Originally Posted by Rlum

Thanks for the information. I have a solar controller and dedicated 100watt panel to trickle charge the chassis battery. I was looking a way to reduce to a single charging source?

Single source for the lithium coach battery? If so, unless you plug in every day, the engine charging is about the only way to single source it.


The engine is not going to give good lithium control of charging though, so much better to put in the B to B and if you are OK with only engine charging, shut off the shore charger completely and make sure the solar isn't connected to the coach batteries.


If it is a bit lithium bank, maybe over 300ah or so, you probably would be best off to install a second dedicated alternator for the shore charging, or upsize the factory one a bunch and use a big B to B charger.

[Rlum]

Originally Posted by booster

Single source for the lithium coach battery? If so, unless you plug in every day, the engine charging is about the only way to single source it.


The engine is not going to give good lithium control of charging though, so much better to put in the B to B and if you are OK with only engine charging, shut off the shore charger completely and make sure the solar isn't connected to the coach batteries.


If it is a bit lithium bank, maybe over 300ah or so, you probably would be best off to install a second dedicated alternator for the shore charging, or upsize the factory one a bunch and use a big B to B charger.

I use the engine and solar for the chassis battery. The house battery is charged primarily by generator and solar. Occasionally shore power. Very seldom is the engine alternator involved with the house battery. I have a cut off switch which disconnects both systems. If the house battery is very low, I will run the generator while driving. It does a great job charging the house lithium.

[blackbourn3704]

Originally Posted by Rlum

Usually not. The isolator separates the chassis battery from house battery. House battery is charged from the converter designed for them. You can design a system where the chassis battery can be charged from shore power. I believe such devices/ systems can be purchased over the counter?

Not normally a problem, but the wife had been sick for a few months and I thought shore power was charging both coach & engine batteries. There is a tiny cabinet under the 3rd seat accessible when the door beside it is open. It has an ac outlet too. Just right size for a small trickle charger and run a wire up to the engine battery. Just leave it plugged in, presto simple shore power charger.

[booster]

Originally Posted by Rlum

I use the engine and solar for the chassis battery. The house battery is charged primarily by generator and solar. Occasionally shore power. Very seldom is the engine alternator involved with the house battery. I have a cut off switch which disconnects both systems. If the house battery is very low, I will run the generator while driving. It does a great job charging the house lithium.

Do you have a selector switch on the solar output so it can't be connected to the starting and coach battery at the same time, or maybe two isolated outputs from the solar charger? You will be constantly running current to the starter from the coach batteries if they are connected without some blocking diodes or such.


How much coach battery capacity to you have? Shore chargers off the generator normally have relatively low output.

[Rlum]

Originally Posted by booster

Do you have a selector switch on the solar output so it can't be connected to the starting and coach battery at the same time, or maybe two isolated outputs from the solar charger? You will be constantly running current to the starter from the coach batteries if they are connected without some blocking diodes or such.


How much coach battery capacity to you have? Shore chargers off the generator normally have relatively low output.

I have a totally isolated solar panel and controller set up for just the chassis battery. It works very well since my van is usually stored in sunny southern California.

House battery bank is quite large. 800Ah. I usually do not run them past a 200 to 300 ah unless using for AC. The charger/inverter puts about 80-90 amps/hr back into the bank. I like this because the generator is constantly being used. Saves having to exercise it. Also it is the new Onan 2800i which is very quiet and vibrates much less. Much better than the previous Onan which came with van.

[avanti]

the Trik-l-Start line of products used to provide a very clean way to interface the house to the chassis battery to keep the latter charged. Sadly, though, it was apparently a one-man company, and he passed away taking the business with him.

I really want to do the equivalent with my new rig, but it is especially tricky because I have a 24V house system. So far, I can't see a better alternative than a small Victron 24-12 charger, which is a bit pricy. I will probably eventually break down and buy one.

[Anachr0n]

The previous owner of my ‘98 Dodge Popular ran a set of wires from the starter battery to the cabin through the dog house with a quick connect tucked behind the carpet. When he was plugged into shore power he’d just plug in a trickle charger into one of the AC outlets and connect it to the starter battery. He kept the charger and I use my van year round so haven’t needed to keep the starter topped up.

[TomF]

I have considered the possibility of a dead starter battery, and I think I could jump the house battery to the start battery at the isolator diode. The reality, however, is that this seems to be a moot point. In 17 years running my 1997 RT, I have never had an issue with the start battery. Mainly, I think that this is because I have a strict rule that the start battery is never used for anything but starting the van. Once the engine is shut off, the stereo and cabin lights are not used, ever, thus, no issues starting the van.