Lithium batteries. - Page 2

Wrinkledpants · 07-10-2016, 12:04 PM

I have an email out to Lithionics to see what they recommend for a whole-house setup (from alternator on back). Seems some of the warranties from various battery manufacturers require a lithium-based charger. That seems like a no-brainer in my book, and they don't appear to be drastically more expensive. I'll be reaching out to each of the companies I've linked to get their feedback on what setup they feel is ideal for something like an SMB. Will keep this thread updated as we go.

arctictraveller · 07-10-2016, 01:39 PM

[QUOTE=Wrinkledpants;178953] Seems some of the warranties from various battery manufacturers require a lithium-based charger. QUOTE]

It's this requirement that I'm most interested in, and how you devise a charge system that meets the requirements of both your house battery and start battery.

Wrinkledpants · 07-10-2016, 02:22 PM

What, specifically, are you interested in? AFAIK - the Sprinter manages the charging of the starter battery, and the lithium is wired up outside of this circuit. The lithium BMS would supply a bulk charge to what it believes is full voltage (less than alternator output), and then shut off the current. Maybe it's different on the Ford vans, but I don't think the the house battery charger would handle the starter battery.

rob_gendreau · 07-10-2016, 03:54 PM

I dunno. I love lithium battery tech, but it's still a bit too complex and expensive. They do seem to have the safety down better, though, so you don't end up going up in flames like a cheap hoverboard. And I assume they are suitably shock resistant for hard use in vehicles. I've had individual lithium cells fail too often, but maybe I just notice more cuz of their cost.

And that brings up service. Make sure the system is such that when you're in Podunkville you can drop in any old battery and be good to go, since you are relying on just one power source, and a rather inefficient one at that.

I went without propane, but I use portable propane for cooking and heating. It just isn't built in. And I've got 10 year old AGMs that are still going strong, with solar (and a portable gennie if I need it for some trips).

And I'm kinda curious; going more than 12v for the stove, right, 36v? Some kinda big ole inverter to do 240 to the stove? I have to admit that in my decades of boating and RVing I've never encountered an electric stove that didn't require shore power.

Wowbagger · 07-10-2016, 04:06 PM

Which Sportsmobile site are you working with? If the Austin site, you can ask them about the build they did for me - I did all the legwork on the LiFePO4 battery install, but I left them with full information on the parts and sources.

I set up 300Ah of 24V (7200W-h total), using batteries and a controller from Elite Power Solutions (www.elitepowersolutions.com). For the kinds of power levels you are wanting I think you will find cells + a controller to be cheaper than the integrated solutions - I paid about $600 per 12V 100Ah battery.

I went with a 24V system to support a 4kW inverter - if you go for a 2kW system you can go 12V, use a battery isolator and your engine's alternator to charge from the engine. I was hoping to run 2 alternators, with the second being 24V, but while I was in the initial planning stages it looked like that wouldn't be a problem, but when the build was done, all the folks doing second alternator sets decided they wouldn't support the Promaster diesel, so I had to go with a 12V to 24V converter to charge my batteries. Since you are going with a Sprinter, you might be able to get a second alternator at 24V.

I mounted the batteries under the rig, with heat-tape in the box to keep them warm if it is cold. Since it's only an issue when charging, I can run the heat tape only when I will be charging, either from shore power or from the inverter.

arctictraveller · 07-10-2016, 05:35 PM

Quote:

Originally Posted by Wrinkledpants

What, specifically, are you interested in? AFAIK - the Sprinter manages the charging of the starter battery, and the lithium is wired up outside of this circuit. The lithium BMS would supply a bulk charge to what it believes is full voltage (less than alternator output), and then shut off the current. Maybe it's different on the Ford vans, but I don't think the the house battery charger would handle the starter battery.

I'm not sure what your saying here, but as you know, lithium batteries require a very different charge profile than say lead acid. Your stock alternator of what ever size has a regulator that is most likely set for lead acid. If that alternator is your only source of recharge voltage outside of shore power, there will need to be a second regulator just for the lithium's. If the alternator senses that the start battery is fully charged (normally in just a few minutes) it will cut back the charge voltage and current. How is that current then increased to charge the lithium, and how do you then prevent overcharging the lead acid start battery? I'd love to see a wiring diagram that shows the connections. You mention the house battery charger, but that's 110v right? How does that play into charging at idle without shore power?

Wrinkledpants · 07-10-2016, 07:11 PM

Quote:

Originally Posted by Wowbagger

Which Sportsmobile site are you working with? If the Austin site, you can ask them about the build they did for me - I did all the legwork on the LiFePO4 battery install, but I left them with full information on the parts and sources.

I set up 300Ah of 24V (7200W-h total), using batteries and a controller from Elite Power Solutions (www.elitepowersolutions.com). For the kinds of power levels you are wanting I think you will find cells + a controller to be cheaper than the integrated solutions - I paid about $600 per 12V 100Ah battery.

I went with a 24V system to support a 4kW inverter - if you go for a 2kW system you can go 12V, use a battery isolator and your engine's alternator to charge from the engine. I was hoping to run 2 alternators, with the second being 24V, but while I was in the initial planning stages it looked like that wouldn't be a problem, but when the build was done, all the folks doing second alternator sets decided they wouldn't support the Promaster diesel, so I had to go with a 12V to 24V converter to charge my batteries. Since you are going with a Sprinter, you might be able to get a second alternator at 24V.

I mounted the batteries under the rig, with heat-tape in the box to keep them warm if it is cold. Since it's only an issue when charging, I can run the heat tape only when I will be charging, either from shore power or from the inverter.

The induction stove will run fine off the 2Kw inverter. What would you need 4kw for? It'll be Fresno doing the install.

Are you controlling the electric tape yourself? I'm hoping to avoid having to manually turn on a heating element as I'd like for solar to do the charging during the day (when available), and we won't be in the van during that time. Hence the reason we're thinking of mounting inside the van. Or, outside the van but with forced air blowing heated air from the interior in some type of custom insulated box.

Wrinkledpants · 07-10-2016, 07:14 PM

Quote:

Originally Posted by arctictraveller

I'm not sure what your saying here, but as you know, lithium batteries require a very different charge profile than say lead acid. Your stock alternator of what ever size has a regulator that is most likely set for lead acid. If that alternator is your only source of recharge voltage outside of shore power, there will need to be a second regulator just for the lithium's. If the alternator senses that the start battery is fully charged (normally in just a few minutes) it will cut back the charge voltage and current. How is that current then increased to charge the lithium, and how do you then prevent overcharging the lead acid start battery? I'd love to see a wiring diagram that shows the connections. You mention the house battery charger, but that's 110v right? How does that play into charging at idle without shore power?

Isn't that what the lithium charger will be doing? You can charge lithium batteries with an AGM charger as long as you can control the voltages during the 3 different stages. I think the main difference is that you're doing a bulk charge for the whole cycle, and the float charge is quite a bit lower (or zero). But - again - this isn't my forte.

Wowbagger · 07-10-2016, 07:23 PM

4kW so that I can run oven and A/C at the same time without any issues. I have the heat tape on a breaker, and switch it on as needed that way (ditto with the backup electric water heater for the Espar - turn it on only when on shore power).

arctictraveller · 07-10-2016, 07:33 PM

Quote:

Originally Posted by Wrinkledpants

Isn't that what the lithium charger will be doing? You can charge lithium batteries with an AGM charger as long as you can control the voltages during the 3 different stages. I think the main difference is that you're doing a bulk charge for the whole cycle, and the float charge is quite a bit lower (or zero). But - again - this isn't my forte.

When you say "charger" I think of a shore powered battery charger. When unplugged, you control your charge parameters with the "voltage regulator" installed in the alternator, or an external one that senses the battery voltage and adjusts the field voltage of the alternator to meet the needed charge parameters. As the battery voltage comes up, the regulator reduces the field voltage there by reducing current and voltage from the alternator. If you adjust said regulator for lithiums, the lead acid start battery will get the same charge parameters. I'm sure there is a way to do this, but I don't know enough to determine what hardware allows charging different chemistry type batteries with one charge source. Or, perhaps you could use an AGM for starting too, but don't they also have a different charge profile than lithium? Perhaps close enough is close enough though.